PHIL 101 SUNY at Stony Brook The Great Conversation Book Ch 18 Discussion

PHIL 101 SUNY at Stony Brook The Great Conversation Book Ch 18 Discussion

Stony Brook The Great Conversation Book Ch 18




You will need to answer the following question concisely and simply. You may bullet point your answer if you like.

1. Contrast the world-picture we get from Galileo and Hobbes with that of Aristotle and medieval thinkers with respect to a description of the universe. (page 415 from the text)


2. Contrast the world-picture we get from Galileo and Hobbes with that of Aristotle and medieval thinkers with respect to the place of values in the world. (page 415 from the text)

3. Describe what Hobbes calls “the state of nature” and explain why it has the character it does have. (page 416 from the text)


4. How does Hobbes think we can have gotten, or can get, beyond the state of nature? (page 416 from the text)

5. What makes Hobbes think that a “social contract” will require the “coercive power” of a state? (page 416 from the text)

6. How does Locke’s notion of a state of nature differ from Hobbes’ notion? (page 427 from the text)

7. What are the “inconveniences” in a state of nature that lead to the formation of a government? (page 427 from the text)

8. Why can’t Locke adopt Hobbes’ view of an absolute sovereignty as the solution for these problems? (page 427 from the text)


9. What is the origin of private property, according to Locke? (page 427 from the text)

10. What sort of government does Locke recommend? (page 427 from the text)


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me, I’ll write those images off as empty illusions.
Talking with myself and looking more deeply into
myself, I’ll try gradually to come to know myself
better. I am a thinking thing—a thing that doubts,
affirms, denies, understands a few things, is ignorant of many things, wills, and refuses. I also sense
and have mental images. For, as I’ve noted, even
though the things of which I have sensations or
mental images may not exist outside me, I’m certain that the modifications of thought called sensations and mental images exist in me insofar as they
are just modifications of thought.
That’s a summary of all that I really know—
or, at any rate, of all that I’ve so far noticed that I
know. I now will examine more carefully whether
there are other things in me that I have not yet
discovered. I’m certain that I am a thinking thing.
Then don’t I know what’s needed for me to be certain of other things? In this first knowledge, there
is nothing but a clear and distinct grasp of what I
affirm, and this grasp surely would not suffice to
make me certain if it could ever happen that something I grasped so clearly and distinctly was false.
Accordingly, I seem to be able to establish the general rule that whatever I clearly and distinctly grasp
is true.
But, in the past, I’ve accepted as completely
obvious and certain many thoughts that I later
found to be dubious. What were these thoughts
about? The earth, the sky, the stars, and other objects of sense. But what did I clearly grasp about
these objects? Only that ideas or thoughts of them
appeared in my mind. Even now, I don’t deny that
these ideas occur in me. But there was something
else that I used to affirm—something that I used to
believe myself to grasp clearly but did not really
grasp at all: I affirmed that there were things besides me, that the ideas in me came from these
things, and that the ideas perfectly resembled these
things. Either I erred here, or I reached a true judgment that wasn’t justified by the strength of my
But what follows? When I considered very
simple and easy points of arithmetic or geometry—
such as that two and three together make five—
didn’t I see them clearly enough to affirm their
truth? My only reason for judging that I ought to
Now we can understand why Descartes introduces the wax example. If even here knowledge
cannot be found in sensation, but only in a “purely
mental inspection,” then we should recognize that
knowledge of what we are must also be approached
in this way. Our tendency to think of ourselves as
what we can sense of ourselves—these hands, this
head, these eyes—is considerably undermined.
Indeed, I must know myself “much more truly and
certainly” even than the wax.
There follows a remarkable conclusion: “I
can’t grasp anything more easily or plainly than my
mind.” (What would Freud have said to that?)
Q13. What qualities, then, belong to the wax
essentially? (Look again at the basic principles of
Descartes’ physics on pp. 361–362.)
Q14. Why is our imagination incapable of grasping
these qualities of the wax? By what faculty do
we grasp it?
Q15. How does the wax example help to cure our
habitual inclination to trust the senses?
Q16. How does our language tend to mislead us?
Meditation III: On God’s Existence
I will now close my eyes, plug my ears, and withdraw all my senses. I will rid my thoughts of the
images of physical objects—or, since that’s beyond
Both inferences seem to be correct. What reason is there
to prefer Bridget’s formulation?
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errors that I find in my judgments is that of assuming
that the ideas in me have a similarity or conformity
to things outside me. For, if I were to regard ideas
merely as modifications of thought, they could not
really provide me with any opportunity for error.
Of my ideas, some seem to me to be innate,
others acquired, and others produced by me. The
ideas by which I understand reality, truth, and
thought seem to have come from my own nature.
Those ideas by which I hear a noise, see the sun, or
feel the fire I formerly judged to come from things
outside me. And the ideas of sirens, hippogriffs,
and so on I have formed in myself. Or maybe I can
take all of my ideas to be acquired, all innate, or all
created by me: I do not yet clearly see where my
ideas come from.
For the moment, the central question is about
the ideas that I view as derived from objects existing outside me. What reason is there for thinking
that these ideas resemble the objects? I seem to
have been taught this by nature. Besides, I find
that these ideas are independent of my will and
hence of me—for they often appear when I do
not want them to do so. For example, I now feel
heat whether I want to or not, and I therefore
take the idea or sensation of heat to come from
something distinct from me: the heat of the fire
by which I am now sitting. And the obvious thing
to think is that a thing sends me its own likeness,
not something else.
I will now see whether these reasons are good
enough. When I say that nature teaches me something, I mean just that I have a spontaneous impulse
to believe it, not that the light of nature reveals the
thing’s truth to me. There is an important difference. When the light of nature reveals something
to me (such as that my thinking implies my existing) that thing is completely beyond doubt, since
there is no faculty as reliable as the light of nature
by means of which I could learn that the thing is not
true. But, as for my natural impulses, I have often
judged them to have led me astray in choices about
what’s good, and I don’t see why I should regard
them as any more reliable on matters concerning
truth and falsehood.
Next, while my sensory ideas may not depend
on my will, it doesn’t follow that they come from
doubt these things was the thought that my Godgiven nature might deceive me even about what
seems most obvious. Whenever I conceive of an allpowerful God, I’m compelled to admit that, if He
wants, He can make it the case that I err even about
what I take my mind’s eye to see most clearly. But,
when I turn to the things that I believe myself to
grasp very clearly, I’m so convinced by them that
I spontaneously burst forth saying, “Whoever may
deceive me, he will never bring it about that I am
nothing while I think that I am something, or that
I have never been when it is now true that I am,
or that two plus three is either more or less than
five, or that something else in which I recognize an
obvious inconsistency is true.” And, since I have no
reason for thinking that God is a deceiver—indeed
since I don’t yet know whether God exists—the
grounds for doubt that rest on the supposition that
God deceives are very weak and “metaphysical.”
Still, to rid myself of these grounds, I ought to ask
as soon as possible whether there is a God and, if
so, whether He can be a deceiver. For it seems
that, until I know these two things, I can never be
completely certain of anything else.
The structure of my project seems to require,
however, that I first categorize my thoughts and
ask in which of them truth and falsity really reside.
Some of my thoughts are like images of things, and
only these can properly be called ideas. I have an
idea, for example, when I think of a man, of a chimera, of heaven, of an angel, or of God. But other
thoughts have other properties: while I always apprehend something as the object of my thought
when I will, fear, affirm, or deny, these thoughts
also include a component in addition to the likeness
of that thing. Some of these components are called
volitions or emotions; others, judgments.
Now, viewed in themselves and without regard
to other things, ideas cannot really be false. If
I imagine a chimera and a goat, it is just as true that
I imagine the chimera as that I imagine the goat.
And I needn’t worry about falsehoods in volitions
or emotions. If I have a perverse desire for something, or if I want something that doesn’t exist, it’s
still true that I want that thing. All that remains,
then, are my judgments; it’s here that I must be
careful not to err. And the first and foremost of the
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something cannot come from nothing and that
what is more perfect—that is, has more reality
in it—cannot come from what is less perfect or
has less reality. This obviously holds, not just for
those effects whose reality is actual or formal, but
also for ideas, whose reality we regard as merely
subjective. For example, it’s impossible for a nonexistent stone to come into existence unless it’s
produced by something containing, either formally
or eminently, everything in the stone. Similarly,
heat can only be induced in something that’s not
already hot by something having at least the same
degree of perfection as heat. Also, it’s impossible
for the idea of heat or of stone to be in me unless it’s
been put there by a cause having at least as much
reality as I conceive of in the heat or the stone.
For, although the cause doesn’t transmit any of its
actual or formal reality to the idea, we shouldn’t
infer that it can be less real than the idea; all that
we can infer is that by its nature the idea doesn’t
require any formal reality except what it derives
from my thought, of which it is a modification.
Yet, as the idea contains one particular subjective
reality rather than another, it must get this reality
from a cause having at least as much formal reality
as the idea has subjective reality. For, if we suppose that an idea has something in it that wasn’t
in its cause, we must suppose that it got this thing
from nothing. However imperfect the existence
of something that exists subjectively in the understanding through an idea, it obviously is something,
and it therefore cannot come from nothing.
And, although the reality that I’m considering
in my ideas is just subjective, I ought not to suspect
that it can fail to be in an idea’s cause formally—that
it’s enough for it to be there subjectively. For, just
as the subjective existence of my ideas belongs to
the ideas in virtue of their nature, the formal existence of the ideas’ causes belongs to those causes—
or, at least, to the first and foremost of them—in
virtue of the causes’ nature. Although one idea may
arise from another, this can’t go back to infinity;
we must eventually arrive at a primary idea whose
cause is an “archetype” containing formally all the
reality that the idea contains subjectively. Hence,
the light of nature makes it clear to me that the
ideas in me are like images that may well fall short
outside me. While the natural impulses of which I
just spoke are in me, they seem to conflict with my
will. Similarly, I may have in me an as yet undiscovered ability to produce the ideas that seem to
come from outside me—in the way that I used to
think that ideas came to me in dreams.
Finally, even if some of my ideas do come from
things distinct from me, it doesn’t follow that
they are likenesses of these things. Indeed, it often
seems to me that an idea differs greatly from its
cause. For example, I find in myself two different
ideas of the sun. One, which I “take in” through the
senses and which I ought therefore to view as a typical acquired idea, makes the sun look very small
to me. The other, which I derive from astronomical reasoning (that is, which I make, perhaps by
composing it from innate ideas), pictures the sun as
many times larger than the earth. It clearly cannot
be that both of these are accurate likenesses of a
sun that exists outside me, and reason convinces
me that the one least like the sun is the one that
seems to arise most directly from it.
All that I’ve said shows that, until now, my
belief that there are things outside me that send
their ideas or images to me (perhaps through my
senses) has rested on blind impulse rather than certain judgment.
Still, it seems to me that there may be a way
of telling whether my ideas come from things that
exist outside me. Insofar as the ideas of things are
just modifications of thought, I find no inequality among them; all seem to arise from me in the
same way. But, insofar as different ideas present
different things to me, there obviously are great
differences among them. The ideas of substances
are unquestionably greater—or have more “subjective reality”—than those of modifications or accidents. Similarly, the idea by which I understand
the supreme God—eternal, infinite, omniscient,
omnipotent, and creator of all things other than
Himself—has more subjective reality in it than the
ideas of finite substances.
Now, the light of nature reveals that there is
at least as much in a complete efficient cause as in
its effect. For where could an effect get its reality if not from its cause? And how could a cause
give something unless it had it? It follows both that
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it were a thing. For example, the ideas that I have
of coldness and heat are so unclear and indistinct
that I can’t tell from them whether coldness is just
the absence of heat, or heat just the absence of
coldness, or both are real qualities, or neither is.
And, since every idea is “of something,” the idea
that presents coldness to me as something real and
positive could justifiably be called false if coldness
were just the absence of heat. And the same holds
true for other ideas of this sort.
For such ideas, I need not posit a creator distinct from me. I know by the light of nature that,
if one of these ideas is false—that is, if it doesn’t
present a real thing—it comes from nothing—that
is, the only cause of its being in me is a deficiency
of my nature, which clearly is imperfect. If one of
these ideas is true, however, I still see no reason
why I couldn’t have produced it myself—for these
ideas present so little reality to me that I can’t even
distinguish it from nothing.
Of the things that are clear and distinct in my
ideas of physical objects, it seems that I may have
borrowed some—such as substance, duration, and
number—from my idea of myself. I think of the
stone as a substance—that is, as something that
can exist on its own—just as I think of myself as
a substance. Although I conceive of myself as a
thinking and unextended thing and of the stone as
an extended and unthinking thing so that the two
conceptions are quite different, they are the same
in that they both seem to be of substances. And,
when I grasp that I exist now while remembering
that I existed in the past, or when I count my various thoughts, I get the idea of duration or number,
which I can then apply to other things. The other
components of my ideas of physical objects—
extension, shape, place, and motion—can’t be in
me formally, since I’m just a thinking thing. But,
as these things are just modes of substance, and as
I am a substance, it seems that they may be in me
All that’s left is my idea of God. Is there something in this idea of God that couldn’t have come
from me? By “God” I mean a substance that’s
infinite, independent, supremely intelligent, and
supremely powerful—the thing from which I and
everything else that may exist derive our existence.
of the things from which they derive, but cannot
contain anything greater or more perfect.
The more time and care I take in studying this,
the more clearly and distinctly I know it to be true.
But what follows from it? If I can be sure that the
subjective reality of one of my ideas is so great
that it isn’t in me either formally or eminently and
hence that I cannot be the cause of that idea, I can
infer that I am not alone in the world—that there
exists something else that is the cause of the idea.
But, if I can find no such idea in me, I will have no
argument at all for the existence of anything other
than me—for, having diligently searched for such
an argument, I have yet to find one.
Of my ideas—besides my idea of myself, about
which there can be no problem here—one presents God, others inanimate physical objects, others
angels, others animals, and still others men like me.
As to my idea of other men, of animals, and of
angels, it’s easy to see that—even if the world contained no men but me, no animals, and no angels—
I could have composed these ideas from those that
I have of myself, of physical objects, and of God.
And, as to my ideas of physical objects, it seems
that nothing in them is so great that it couldn’t have
come from me. For, if I analyze my ideas of physical objects carefully, taking them one by one as I
did yesterday when examining my idea of the piece
of wax, I notice that there is very little in them
that I grasp clearly and distinctly. What I do grasp
clearly and distinctly in these ideas is size (which
is extension in length, breadth, and depth), shape
(which arises from extension’s limits), position
(which the differently shaped things have relative
to one another), and motion (which is just change
of position). To these I can add substance, duration, and number. But my thoughts of other things
in physical objects (such as light and color, sound,
odor, taste, heat and cold, and tactile qualities) are
so confused and obscure that I can’t say whether
they are true or false—whether my ideas of these
things are of something or of nothing. Although,
as I noted earlier, that which is properly called
falsehood—namely, formal falsehood—can only be
found in judgments, we can still find falsehood of
another sort—namely, material falsehood—in an
idea when it presents what is not a thing as though
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But maybe I am greater than I have assumed;
maybe all the perfections that I attributed to God
are in me potentially, still unreal and unactualized. I
have already seen my knowledge gradually increase,
and I don’t see anything to prevent its becoming
greater and greater to infinity. Nor do I see why,
by means of such increased knowledge, I couldn’t
get all the rest of God’s perfections. Finally, if the
potential for these perfections is in me, I don’t see
why that potential couldn’t account for the production of the ideas of these perfections in me.
None of this is possible. First, while it’s true
that my knowledge gradually increases and that I
have many as yet unactualized potentialities, none
of this fits with my idea of God, in whom absolutely
nothing is potential; indeed, the gradual increase in
my knowledge shows that I am imperfect. Besides,
I see that, even if my knowledge were continually to become greater and greater, it would never
become actually infinite, since it would never
become so great as to be unable to increase. But
I judge God to be actually infinite so that nothing
can be added to his perfection. Finally, I see that an
idea’s subjective being must be produced, not by
mere potentiality (which, strictly speaking, is nothing), but by what is actual or formal.
When I pay attention to these things, the light
of nature makes all of them obvious. But, when
I attend less carefully and the images of sensible
things blind my mind’s eye, it’s not easy for me to
remember why the idea of an entity more perfect
than I am must come from an entity that really is
more perfect. That’s why I’ll go on to ask whether
I, who have the idea of a perfect entity, could exist
if no such entity existed.
From what might I derive my existence if not
from God? Either from myself, or from my parents, or from something else less perfect than
God—for nothing more perfect than God, or even
as perfect as Him, can be thought of or imagined.
But, if I derived my existence from myself, I
wouldn’t doubt, or want, or lack anything. I would
have given myself every perfection of which I have
an idea, and thus I myself would be God. And I
shouldn’t think that it might be harder to give
myself what I lack than what I already have. On
the contrary, it would obviously be much harder
The more I consider these attributes, the less it
seems that they could have come from me alone.
So I must conclude that God necessarily exists.
While I may have the idea of substance in me by
virtue of my being a substance, I who am finite would
not have the idea of infinite substance in me unless it
came from a substance that really was infinite.
And I shouldn’t think that, rather than having
a true idea of infinity, I grasp it merely as the absence of limits—in the way that I grasp rest as the
absence of motion and darkness as the absence of
light. On the contrary, it’s clear to me that there
is more reality in an infinite than in a finite substance and hence that my grasp of the infinite must
somehow be prior to my grasp of the finite—my
understanding of God prior to my understanding
of myself. For how could I understand that I doubt
and desire, that I am deficient and imperfect, if I
didn’t have the idea of something more perfect to
use as a standard of comparison?
And, unlike the ideas of hot and cold which I just
discussed, the idea of God cannot be said to be materially false and hence to come from nothing. On
the contrary, since the idea of God is completely
clear and distinct and contains more subjective reality than any other idea, no idea is truer per se and
none less open to the suspicion of falsity. The idea
of a supremely perfect and infinite entity is, I maintain, completely true. For, while I may be able to
suppose that there is no such entity, I can’t even
suppose (as I did about the idea of coldness) that my
idea of God fails to show me something real. This
idea is maximally clear and distinct, for it contains
everything that I grasp clearly and distinctly, everything real and true, everything with any perfection.
It doesn’t matter that I can’t fully comprehend the
infinite—that there are innumerable things in God
which I can’t comprehend fully or even reach with
thought. Because of the nature of the infinite, I who
am finite cannot comprehend it. It’s enough that I
think about the infinite and judge that, if I grasp
something clearly and distinctly and know it to
have some perfection, it’s present either formally
or eminently—perhaps along with innumerable
other things of which I am ignorant—in God. If I
do this, then of all my ideas the idea of God will be
most true and most clear and distinct.
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ask whether this thing gets its existence from itself
or from something else. If it gets its existence from
itself, it’s obvious from what I’ve said that it must
be God—for it would have the power to exist on
its own and hence the power actually to give itself
every perfection of which it has an idea, including
every perfection that I conceive of in God. But, if
my cause gets its existence from some other thing,
we can go on to ask whether this other thing gets its
existence from itself or from something else. Eventually, we will come to the ultimate cause, which
will be God.
It’s clear enough that there can’t be an infinite
regress here—especially since I am concerned, not
so much with the cause that originally produced
me, as with the one that preserves me at the present moment.
And I can’t suppose that several partial causes
combined to make me or that I get the ideas of the
various perfections that I attribute to God from different causes so that, while each of these perfections can
be found somewhere in the universe, there is no God
in whom they all come together. On the contrary,
one of the chief perfections that I understand God to
have is unity, simplicity, inseparability from everything in Him. Surely the idea of the unity of all God’s
perfections can only have been put in me by a cause
that gives me the ideas of all the other perfections—
for nothing could make me aware of the unbreakable
connection of God’s perfections unless it made me
aware of what those perfections are.
Finally, even if everything that I used to believe
about my parents is true, it’s clear that they don’t
preserve me. Insofar as I am a thinking thing, they
did not even take part in creating me. They simply
formed the matter in which I used to think that
I (that is, my mind, which is all I am now taking
myself to be) resided. There can therefore be no
problem about my parents. And I am driven to this
conclusion: The fact that I exist and have an idea in
me of a perfect entity—that is, God—conclusively
entails that God does in fact exist.
All that’s left is to explain how I have gotten my
idea of God from Him. I have not taken it in through
my senses; it has never come to me unexpectedly
as the ideas of sensible things do when those things
affect (or seem to affect) my external organs of
for me, a thinking thing or substance, to emerge
from nothing than for me to give myself knowledge of the many things of which I am ignorant,
which is just an attribute of substance. But surely,
if I had given myself that which is harder to get, I
wouldn’t have denied myself complete knowledge,
which would have been easier to get. Indeed, I
wouldn’t have denied myself any of the perfections
that I grasp in the idea of God. None of these perfections seems harder to get than existence. But,
if I had given myself everything that I now have,
these perfections would have seemed harder to get
than existence if they were harder to get—for in
creating myself I would have discovered the limits
of my power.
I can’t avoid the force of this argument by supposing that, since I’ve always existed as I do now,
there’s no point in looking for my creator. Since
my lifetime can be divided into innumerable parts
each of which is independent of the others, the fact
that I existed a little while ago does not entail that
I exist now, unless a cause “recreates” me—or, in
other words, preserves me—at this moment. For,
when we attend to the nature of time, it’s obvious that exactly the same power and action are required to preserve a thing at each moment through
which it endures as would be required to create
it anew if it had never existed. Hence, one of the
things revealed by the light of nature is that preservation and creation differ only in the way we think
of them.
I ought to ask myself, then, whether I have the
power to ensure that I, who now am, will exist
in a little while. Since I am nothing but a thinking thing—or, at any rate, since I am now focusing
on the part of me that thinks—I would surely be
aware of this power if it were in me. But I find no
such power. And from this I clearly see that there
is an entity distinct from me on whom I depend.
But maybe this entity isn’t God. Maybe I am the
product of my parents or of some other cause less
perfect than God. No. As I’ve said, there must be
at least as much in a cause as in its effect. Hence,
since I am a thinking thing with the idea of God
in me, my cause, whatever it may be, must be a
thinking thing having in it the idea of every perfection that I attribute to God. And we can go on to
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Commentary and Questions
In the first paragraphs, Descartes resolves to
explore more carefully his own mind. But then
what alternative does he have, now that he has
resolved to consider everything else “as empty
A momentous step is taken: He solves (or at
least he thinks he solves) the problem of the criterion! Here are the steps.
1. He is certain that he exists as a thinking
2. He asks himself, What is it about this proposition that accounts for my certainty that it is true?
3. He answers, The fact that I grasp it so clearly
and distinctly that I perceive it could not possibly be false.
4. He concludes, Let this then be a general principle (a criterion): Whatever I grasp with like clarity and distinctness must also be true.
He then reviews (yet again) the things he had
at one time thought were true and reminds himself
that no matter how sure he feels about them, he
can’t be absolutely certain.
Q17. Why does he feel a need to inquire about the
existence and nature of God?
Descartes now tries to make clear a crucial
distinction between ideas on the one hand and
volitions, emotions, and judgments on the other
(pp. 376–377). This distinction is embedded in an
inventory of the varied contents of the mind (which
is all that we can so far be certain of). You will find
a schematic representation of that inventory in the
following diagram.
sense. Nor have I made the idea myself; I can’t subtract from it or add to it. The only other possibility is
that the idea is innate in me, like my idea of myself.
It’s not at all surprising that in creating me God
put this idea into me, impressing it on His work
like a craftsman’s mark (which needn’t be distinct
from the work itself). The very fact that it was God
who created me confirms that I have somehow
been made in His image or likeness and that I grasp
this likeness, which contains the idea of God, in the
same way that I grasp myself. Thus, when I turn my
mind’s eye on myself, I understand, not just that I
am an incomplete and dependent thing which constantly strives for bigger and better things, but also
that He on whom I depend has all these things in
Himself as infinite reality rather than just as vague
potentiality and hence that He must be God. The
whole argument comes down to this: I know that
I could not exist with my present nature—that
is, that I could not exist with the idea of God in
me—unless there really were a God. This must be
the very God whose idea is in me, the thing having
all of the perfections that I can’t fully comprehend
but can somehow reach with thought, who clearly
cannot have any defects. From this, it’s obvious
that He can’t deceive—for, as the natural light reveals, fraud and deception arise from defect.
But before examining this more carefully and
investigating its consequences, I want to dwell
for a moment in the contemplation of God, to
ponder His attributes, to see and admire and adore
the beauty of His boundless light, insofar as my
clouded insight allows. As I have faith that the supreme happiness of the next life consists wholly of
the contemplation of divine greatness, I now find
that contemplation of the same sort, though less
perfect, affords the greatest joy available in this life.
Contents of the mind
Ideas Ideas in action
Produced Judgments Volitions Emotions
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when you form an image of a giraffe in your mind,
that image also has formal reality—that is, it actually exists as an image in your mind. So any idea actually present in a mind is formally real. This means
that (if there are giraffes) both the idea of a giraffe
(when being thought) and the giraffe you are thinking of are formally real. They are distinct realities,
but related: The one represents the other.
What you are thinking about when you entertain an idea has subjective reality, reality “for you.”
Thus, when you think about giraffes and angels,
they have both formal and subjective reality. The
objects of some ideas, though, have only subjective
reality: the tooth fairy, for instance, or unicorns.
These, of course, are examples of ideas “produced
by us.” But if we look carefully, we can see that they
have not been invented out of nothing. The idea of
a unicorn comes from the ideas of a horse and a
single horn. And (though Descartes has not proved
it yet) it may be that horses and horns are formally
real. Already he remarks (p. 377) that although
one idea may be derived from others, this cannot
go on to infinity: There must eventually be a cause
for these ideas; and the reality of that cause must
be more than “merely subjective.” If this were not
so, we would have gotten something “from nothing.” And the light of nature assures us that this is
impossible. There is an old Latin saying: ex nihilo
nihil fit, or “from nothing, nothing comes.”
Descartes does not, of course, make these distinctions for their own sake. There is a problem he
is trying to solve: Given that I can be certain that
I exist (together with all my ideas), can I be certain
of the formal existence of anything else? Although
thoroughgoing skepticism may have been refuted
(we do know something in the cogito), we have not
got beyond solipsism. Solipsism is a view that each
of you (if there is anyone out there!) must state for
yourself in this way: “I am the only thing that actually (formally) exists; everything else is only subjectively real.”
Another step in solving that problem is to note
that there are degrees of reality: some things have
more reality than others. This is the cardinal principle of the Great Chain of Being.* Descartes gives
*See pp. 271–272.
Q18. What is the key difference between ideas and
Q19. What is the key difference between judgments
on the one hand and volitions and emotions on
the other?
Q20. What question arises with respect to the ideas
that seem to be acquired from outside myself?
Q21. What (provisional) examples does Descartes
give of each class of ideas?
We need to comment on the notion of innate
ideas. In calling them “innate,” Descartes does not
mean to imply that they are to be found in babies
and mentally defective adults, as some of his critics suppose. He merely means that there are some
ideas we would have even if nothing existed but
ourselves. These ideas do not require external
causes for their existence in us; every developed
rational mind will possess them from its own resources. Thus, the idea of a thing can originate with
the cogito, which gives me the certainty that I exist
as a thing that thinks—even if nothing else exists.
Perhaps my idea of an antelope is caused in me only
by seeing antelopes in a zoo (though this remains to
be proved). But we would have the ideas of thing,
thought, and truth in any case.
Q22. Why do you think Descartes believes that the
ideas of truth and thought are innate?
Q23. Why is he inclined to believe that some ideas do
originate from objects outside himself? He gives
two reasons (p. 377).
Q24. Are these two reasons conclusive?
Q25. What is the difference between being taught “by
nature” and being taught “by the light of nature”?
(See p. 376.) What is the light of nature?
We come now to a point of terminology. Descartes distinguishes subjective reality on the one
hand from formal and eminent reality on the
other. If we are going to understand Descartes’ argument, we must be clear about how he uses these
terms and keep his use firmly in mind.
It is easier to begin with formal reality. Something has formal reality if it is, in our terms, actual
or existing. If there really are giraffes and angels,
then giraffes and angels have formal reality. You
also, because you exist, have formal reality. And
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7. So there must be a formal reality that is an
infinitely perfect substance.
8. So God exists.
Q29. Is this argument valid?
Q30. Are there premises in the argument that are less
than certainly true?
Meditation III contains two separate arguments
for God’s existence. The first one, which we have
now examined, begins with the fact that each of
us has an idea of God. The second one begins (on
p. 379) with the fact that I exist. The argument
then addresses whether I could exist if God does
not. It is an argument by exclusion; it considers
the other plausible candidates for the cause of my
existence and shows in each case that it won’t do.
Note that both arguments are causal arguments.
The first inquires about the cause of my idea of
God and the second about the cause of my existence.
Both make use of the causal principle Descartes has
Let us sketch the principal steps in this argument.
1. I exist.
2. There must be a cause for my existence.
3. The cause must be one of the following:
(a) myself, (b) my always having existed, (c)
my parents, (d) something else less perfect than
God, or (e) God.
4. Not (a), or I would have given myself perfections I now lack—because creating the properties of a substance is not as hard as creating the
substance itself.
5. Not (b), because my existing now does not
follow from my having existed in the past.
6. Not (c), for this leads to an infinite regress.
7. Not (d), for this couldn’t account for the unity
of the idea of God that I have.
8. So (e), and God exists.
Q31. Is there a weak point in this argument? Is there
more than one?
Q32. Why does Descartes think his idea of God must
be innate?
Q33. Explain why Descartes says we cannot
“comprehend” God but can “reach” him in
two examples, framed in terms of subjective reality
(p. 377), though the same is true for formal reality
as well.
Q26. Why does the idea of substance contain more
subjective reality than that of modification or
accident? (Think of a fender and the dent in it.)*
Q27. Why does the idea of infinite substance have
more subjective reality than that of finite
On the basis of these distinctions, Descartes
formulates a causal principle: There must be at least
as much reality in the cause as there is in the effect.
A cause is said to be formally real when it has the
same degree of reality as the effect it produces; it
is said to be eminently real when it has even more
reality than its effect.
Q28. What examples does Descartes offer to illustrate
this causal principle?
Once more Descartes canvases the various
kinds of ideas he finds in himself as a thinking thing.
He is looking for some idea of which he himself
could not possibly be the cause. Such an idea must
have a cause (since nothing comes from nothing). If
(1) he is not the cause and (2) there is a cause, then
(3) he knows that he is not alone in the universe.
Something else exists!
Descartes thinks his meditations to this point
give him the materials with which to prove that God
exists. Let us see what the argument looks like:
1. I have an idea of an infinitely perfect substance.
2. Such an idea must have a cause.
3. Ex nihilo nihil fit.
4. So the cause of an idea must have at least as
much formal reality as there is subjective reality
in the idea.
5. Though I am a substance, I am not infinitely
6. So I could not be the cause of this idea.
*We owe this nice example to Ronald Rubin, the translator of these Meditations.
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In the first place, I know that it’s impossible
for Him ever to deceive me. Wherever there is
fraud and deception, there is imperfection, and,
while the ability to deceive may seem a sign of
cunning or power, the desire to deceive reveals
malice or weakness and hence is inconsistent with
God’s nature.
Next, I find in myself an ability to judge which,
like everything else in me, I’ve gotten from God.
Since He doesn’t want to deceive me, He certainly
hasn’t given me an ability which will lead me wrong
when properly used.
There can be no doubt about this—except that
it may seem to imply that I don’t err at all. For,
if I’ve gotten everything in me from God and He
hasn’t given me the ability to err, it doesn’t seem
possible for me ever to err. Thus, as long as I think
only of God and devote all my attention to Him,
I can’t find any cause for error and falsity. When
I turn my attention back to myself, however, I find
that I can make innumerable errors. In looking for
the cause of these errors, I find before me, not just
the real and positive idea of God, but also the negative idea of “nothingness”—the idea of that which
is completely devoid of perfection. I find that I am
“intermediate” between God and nothingness, between the supreme entity and nonentity. Insofar
as I am the creation of the supreme entity, there’s
nothing in me to account for my being deceived or
led into error, but, insofar as I somehow participate in nothingness or the nonentity—that is, insofar as I am distinct from the supreme entity itself
and lack many things—it’s not surprising that I go
wrong. I thus understand that, in itself, error is a
lack, rather than a real thing dependent on God.
Hence, I understand that I can err without God’s
having given me a special ability to do so. Rather,
I fall into error because my God-given ability to
judge the truth is not infinite.
But there’s still something to be explained.
Error is not just an absence, but a deprivation—
the lack of knowledge that somehow ought to be in
me. But, when I attend to God’s nature, it seems
impossible that He’s given me an ability that is an
imperfect thing of its kind—an ability lacking a
perfection that it ought to have. The greater the
craftsman’s skill, the more perfect his product.
thought. (Compare touching an elephant and
wrapping your arms around it.)*
At the end of the third meditation, Descartes
feels he has achieved his aim. He now knows that
he is not alone. In addition to himself, there is
at least one other being—a substance infinite in
intelligence and power and perfect in every way.
This latter fact will prove to be of very great
significance, for Descartes will use it to defeat
the hypothesis of the evil demon; a perfect being
could not be a deceiver. Thus he thinks he can
overcome the deepest ground for skepticism
about knowledge of the external world. But that
is a line of argument pursued in the remaining
Meditation IV: On Truth and Falsity
In the last few days, I’ve gotten used to drawing
my mind away from my senses. I’ve carefully noted
that I really grasp very little about physical objects,
that I know much more about the human mind,
and that I know even more about God. Thus, I
no longer find it hard to turn my thoughts away
from things of which I can have mental images and
toward things completely separate from matter,
which I can only understand. Indeed, I have a much
more distinct idea of the human mind, insofar as it
is just a thinking thing that isn’t extended in length,
breadth, or depth and doesn’t share anything else
with physical objects, than I have of physical objects. And, when I note that I doubt or that I am
incomplete and dependent, I have a clear and distinct idea of a complete and independent entity:
God. From the fact that this idea is in me and that I
who have the idea exist, I can clearly infer both that
God exists and that I am completely dependent on
Him for my existence from moment to moment.
This is so obvious that I’m sure that people can’t
know anything more evidently or certainly. And it
now seems to me that, from the contemplation of
the true God in whom are hidden all treasures of
knowledge and wisdom, there is a way to derive
knowledge of other things.
* Compare the similar thought by Aquinas, p. 324.
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Nor can I complain about the scope or perfection of my God-given freedom of will—for I find
that my will doesn’t seem to me to be restricted in
any way. Indeed, it seems well worth noting that
nothing in me other than my will is so great and
perfect that it couldn’t conceivably be bigger or
better. If I think about my ability to understand, for
example, I realize that it is very small and restricted
and I immediately form the idea of something much
greater—indeed, of something supremely perfect
and infinite. And, from the fact that I can form the
idea of this thing, I infer that it is present in God’s
nature. Similarly, if I consider my other abilities,
like the abilities to remember and to imagine,
I clearly see that they all are weak and limited in
me, but boundless in God. My will or freedom of
choice is the only thing I find to be so great in me
that I can’t conceive of anything greater. In fact,
it’s largely for this reason that I regard myself as
an image or likeness of God. God’s will is incomparably greater than mine, of course, in virtue of
the associated knowledge and power that make it
stronger and more effective, and also in virtue of all
its greater range of objects. Yet, viewed in itself as
a will, God’s will seems no greater than mine. For
having a will just amounts to being able either to
do or not to do (affirm or deny, seek or avoid)—
or, better, to being inclined to affirm or deny, seek
or shun what the understanding offers, without any
sense of being driven by external forces. To be free,
I don’t need to be inclined towards both alternatives. On the contrary, the more I lean towards one
alternative—either because I understand the truth
or goodness in it, or because God has so arranged
my deepest thoughts—the more freely I choose
it. Neither divine grace nor knowledge of nature
ever diminishes my freedom; they increase and
strengthen it. But the indifference that I experience
when no consideration impels me towards one alternative over another is freedom of the lowest sort,
whose presence reveals a defect or an absence of
knowledge rather than a perfection. For, if I always
knew what was good or true, I wouldn’t ever deliberate about what to do or choose, and thus, though
completely free, I would never be indifferent.
From this I see that my God-given ability to
will is not itself the cause of my errors—for my
Then how can the supreme creator of all things
have made something that isn’t absolutely perfect?
There’s no doubt that God could have made me so
that I never err and that He always wants what’s
best. Then is it better for me to err than not to err?
When I pay more careful attention, I realize
that I shouldn’t be surprised at God’s doing things
that I can’t explain. I shouldn’t doubt His existence
just because I find that I sometimes can’t understand why or how He has made something. I know
that my nature is weak and limited and that God’s
is limitless, incomprehensible, and infinite, and,
from this, I can infer that He can do innumerable
things whose reasons are unknown to me. On this
ground alone, I regard the common practice of explaining things in terms of their purposes to be useless in physics: it would be foolhardy of me to think
that I can discover God’s purposes.
It also seems to me that, when asking whether
God’s works are perfect, I ought to look at all of
them together, not at one in isolation. For something that seems imperfect when viewed alone
might seem completely perfect when regarded as
having a place in the world. Of course, since calling everything into doubt, I haven’t established that
anything exists besides me and God. But, when I
consider God’s immense power, I can’t deny that
He has made—or, in any case, that He could have
made—many other things, and I must therefore
view myself as having a place in a universe.
Next, turning to myself and investigating the
nature of my errors (which are all that show me to be
imperfect), I notice that these errors depend on two
concurrent causes: my ability to know and my ability to choose freely—that is, my understanding and
my will. But, with my understanding, I just grasp
the ideas about which I form judgments, and error
therefore cannot properly be said to arise from the
understanding itself. While there may be innumerable things of which I have no idea, I can’t say that
I am deprived of these ideas, but only that I happen
to lack them—for I don’t have any reason to think
that God ought to have given me a greater ability to
know than He has. And, while I understand God
to be a supremely skilled craftsman, I don’t go on
to think that He ought to endow each of his works
with all the perfections that He can put in the others.
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right and am not deceived. But, if I either affirm
or deny in a case of this sort, I misuse my freedom of choice. If I affirm what is false, I clearly
err, and, if I stumble onto the truth, I’m still
blameworthy since the light of nature reveals that
a perception of the understanding should always
precede a decision of the will. In these misuses
of freedom of choice lies the deprivation that accounts for error. And this deprivation, I maintain, lies in the working of the will insofar as it
comes from me—not in my God-given ability to
will, or even in the will’s operation insofar as it
derives from Him.
I have no reason to complain that God hasn’t
given me a more perfect understanding or a greater
natural light than He has. It’s in the nature of a
finite understanding that there are many things it
can’t understand, and it’s in the nature of created
understanding that it’s finite. Indeed, I ought to
be grateful to Him who owes me absolutely nothing for what He has bestowed, rather than taking
myself to be deprived or robbed of what God
hasn’t given me.
And I have no reason to complain about God’s
having given me a will whose scope is greater than
my understanding’s. The will is like a unity made
of inseparable parts; its nature apparently will not
allow anything to be taken away from it. And,
really, the wider the scope of my will, the more
grateful I ought to be to Him who gave it to me.
Finally, I ought not to complain that God concurs in bringing about the acts of will and judgment in which I err. Insofar as these acts derive
from God, they are completely true and good,
and I am more perfect with the ability to perform
these acts than I would be without it. And, the
deprivation that is the real ground of falsity and
error doesn’t need God’s concurrence, since it’s
not a thing. When we regard God as its cause, we
should say that it is an absence rather than a deprivation. For it clearly is no imperfection in God
that He has given me the freedom to assent or not
to assent to things of which He hasn’t given me a
clear and distinct grasp. Rather, it is undoubtedly
an imperfection in me that I misuse this freedom
by passing judgment on things that I don’t properly understand. I see, of course, that God could
will is great, a perfect thing of its kind. Neither is
my power of understanding the cause of my errors;
whenever I understand something, I understand it
correctly and without the possibility of error, since
my understanding comes from God. What then is
the source of my errors? It is just that, while my
will has a broader scope than my understanding, I
don’t keep it within the same bounds, but extend
it to that which I don’t understand. Being indifferent to these things, my will is easily led away from
truth and goodness, and thus I am led into error
and sin.
For example, I’ve asked for the last few days
whether anything exists in the world, and I’ve
noted that, from the fact that I ask this, it follows
that I exist. I couldn’t fail to judge that which I so
clearly understood to be true. This wasn’t because
a force outside me compelled me to believe, but
because an intense light in my understanding produced a strong inclination of my will. And, to the
extent that I wasn’t indifferent, I believed spontaneously and freely. However, while I now know
that I exist insofar as I am a thinking thing, I notice
in myself an idea of what it is to be a physical object
and I come to wonder whether the thinking nature
that’s in me—or, rather, that is me—differs from
this bodily nature or is identical to it. Nothing
occurs to my reason (I am supposing) to convince
me of one alternative rather than the other. Accordingly, I am completely indifferent to affirming
either view, to denying either view, and even to
suspending judgment.
And indifference of this sort is not limited to
things of which the understanding is completely ignorant. It extends to everything about which the
will deliberates in the absence of a sufficiently clear
understanding. For, however strong the force with
which plausible conjectures draw me towards one
alternative, the knowledge that they are conjectures rather than assertions backed by certain and
indubitable arguments is enough to push my assent
the other way. The past few days have provided
me with ample experience of this—for I am now
supposing each of my former beliefs to be false just
because I’ve found a way to call them into doubt.
If I suspend judgment when I don’t clearly
and distinctly grasp what’s true, I obviously do
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Commentary and Questions
Note the transitional character of the first paragraph. Descartes sums up the argument so far, expresses his confidence that God’s existence is more
certain than anything else (except the cogito), and
looks forward to further progress.
Q34. Is Descartes’ assertion (p. 384) that deception
is an evidence of weakness rather than power
plausible? Explain your answer.
Before God’s existence was proved, it was unclear whether any of our beliefs were true. Now
there is a new puzzle: How can any of them be
false? (Do you see why this puzzle arises?) So Descartes has to provide an explanation of the obvious
fact that we can and do make mistakes.
For the basic framework he depends again on
the idea of the Great Chain of Being. He finds that
he is an “intermediate” between God and nothingness, having less reality than God, whose perfection
excludes error, but more reality than sheer nonbeing. Error, in any case, is not a positive reality; it
is only a defect, as weakness is only the absence of
strength and cold the absence of heat. So it should
not be too surprising that Descartes, and we, too,
should be susceptible to error.
Two points he makes in passing are worth
1. Why did God create me so that I could make
mistakes? I don’t know, he says, but if I could
see the world as God sees it, it is quite possible
that I would judge it to be for the best.*
Q35. How does recognizing that you are only a part of
a larger whole help answer this question?
* Here is one expression of that attitude expressed in
Leibniz and other later writers to the effect that “this is the
best of all possible worlds.” It is this optimism that Voltaire caricatures so savagely in Candide. These reflections
of Descartes form part of a project known as theodicy—the
justification of the ways of God to man. For another attempt
at theodicy, see Hegel (pp. 516–519). You might also review
the Stoic notion that evil does not exist in the world, only in
our perception of it (p. 243).
easily have brought it about that, while I remain
free and limited in knowledge, I never err: He
could have implanted in me a clear and distinct understanding of everything about which I was ever
going to make a choice, or He could have indelibly impressed on my memory that I must never
pass judgment on something that I don’t clearly
and distinctly understand. And I also understand
that, regarded in isolation from everything else,
I would have been more perfect if God had made
me so that I never err. But I can’t deny that, because some things are immune to error while
others are not, the universe is more perfect than
it would have been if all its parts were alike. And I
have no right to complain about God’s wanting me
to hold a place in the world other than the greatest
and most perfect.
Besides, if I can’t avoid error by having a clear
grasp of every matter on which I make a choice, I
can avoid it in the other way, which only requires
remembering that I must not pass judgment on
matters whose truth isn’t apparent. For, although
I find myself too weak to fix my attention permanently on this single thought, I can—by careful and
frequent meditation—ensure that I call it to mind
whenever it’s needed and thus that I acquire the
habit of avoiding error.
Since the first and foremost perfection of man
lies in avoiding error, I’ve profited from today’s
meditation, in which I’ve investigated the cause
of error and falsity. Clearly, the only possible
cause of error is the one I have described. When
I limit my will’s range of judgment to the things
presented clearly and distinctly to my understanding, I obviously cannot err—for everything that
I clearly and distinctly grasp is something and
hence must come, not from nothing, but from
God—God, I say, who is supremely perfect and
who cannot possibly deceive. Therefore, what I
clearly and distinctly grasp is unquestionably true.
Today, then, I have learned what to avoid in order
not to err and also what to do to reach the truth.
I surely will reach the truth if I just attend to the
things that I understand perfectly and distinguish
them from those that I grasp more obscurely and
confusedly. And that’s what I’ll take care to do
from now on.
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In addition to having a thorough knowledge of
extension in general, I grasp innumerable particulars about things like shape, number, and motion,
when I pay careful attention. The truth of these
particulars is so obvious and so consonant with
my nature that, when I first think of one of these
things, I seem not so much to be learning something novel as to be remembering something that I
already knew—or noticing for the first time something that had long been in me without my having
turned my mind’s eye toward it.
What’s important here, I think, is that I find
in myself innumerable ideas of things which,
though they may not exist outside me, can’t be
said to be nothing. While I have some control
over my thoughts of these things, I do not make
the things up: they have their own real and immutable natures. Suppose, for example, that I have a
mental image of a triangle. While it may be that
no figure of this sort does exist or ever has existed
outside my thought, the figure has a fixed nature
(essence or form), immutable and eternal, which
hasn’t been produced by me and isn’t dependent
on my mind. The proof is that I can demonstrate
various propositions about the triangle, such as that
its angles equal two right angles and that its greatest side subtends its greatest angle. Even though
I didn’t think of these propositions at all when I
first imagined the triangle, I now clearly see their
truth whether I want to or not, and it follows that I
didn’t make them up.
It isn’t relevant that, having seen triangular
physical objects, I may have gotten the idea of the
triangle from external objects through my organs
of sense. For I can think of innumerable other
figures whose ideas I could not conceivably have
gotten through my senses, and I can demonstrate
facts about these other figures just as I can about
the triangle. Since I know these facts clearly, they
must be true, and they therefore must be something rather than nothing. For it’s obvious that everything true is something, and, as I have shown,
everything that I know clearly and distinctly is true.
But, even if I hadn’t shown this, the nature of my
mind would have made it impossible for me to
withhold my assent from these things, at least when
I clearly and distinctly grasped them. As I recall,
2. Among the many things we do not know are
God’s purposes. It follows that Aristotelian final
causes—the what for—are not appropriate in
the explanations given by physics. Thus Descartes
buttresses the mechanistic character of his (and
the modern world’s) scientific work. We can
come to know how things happen, but not why.
A more detailed analysis of error can be given.
It depends on the distinction between entertaining a
belief, or having it in mind (which is the function of
the understanding), and assenting to that belief,
or accepting it (which is the function of the will).
Q36. How does this distinction between
understanding and will explain the possibility of
Q37. In what way is the will more perfect than the
Q38. Can God be blamed for our errors?
Q39. How can we avoid error?
Meditation V: On the Essence
of Material Objects and More
on God’s Existence
Many questions remain about God’s attributes and
the nature of my self or mind. I may return to these
questions later. But now, having found what to do
and what to avoid in order to attain truth, I regard
nothing as more pressing than to work my way out
of the doubts that I raised the other day and to see
whether I can find anything certain about material
But, before asking whether any such objects
exist outside me, I ought to consider the ideas of
these objects as they exist in my thoughts and see
which are clear and which confused.
I have a distinct mental image of the quantity
that philosophers commonly call continuous. That
is, I have a distinct mental image of the extension of
this quantity—or rather of the quantified thing—in
length, breadth, and depth. I can distinguish various parts of this thing. I can ascribe various sizes,
shapes, places, and motions to these parts and various durations to the motions.
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separated from one another. But, from the fact that
I can’t think of God without existence, it follows
that existence is inseparable from Him and hence
that He really exists. It’s not that my thoughts
make it so or impose a necessity on things. On
the contrary, it’s the fact that God does exist that
necessitates my thinking of Him as I do. For I am
not free to think of God without existence—of
the supremely perfect being without supreme
perfection—as I am free to think of a horse with or
without wings.
Now someone might say this: “If I take God to
have all perfections, and if I take existence to be a
perfection, I must take God to exist, but I needn’t
accept the premise that God has all perfections.
Similarly, if I accept the premise that every quadrilateral can be inscribed in a circle, I’m forced to the
patently false view that every rhombus can be inscribed in a circle, but I need not accept the premise.” But this should not be said. For, while it’s not
necessary that the idea of God occurs to me, it is
necessary that, whenever I think of the primary and
supreme entity and bring the idea of Him out of
my mind’s “treasury,” I attribute all perfections to
Him, even if I don’t enumerate them or consider
them individually. And this necessity ensures that,
when I do notice that existence is a perfection, I
can rightly conclude that the primary and supreme
being exists. Similarly, while it’s not necessary
that I ever imagine a triangle, it is necessary that,
when I do choose to consider a rectilinear figure
having exactly three angles, I attribute to it properties from which I can rightly infer that its angles
are no more than two right angles, perhaps without noticing that I am doing so. But, when I consider which shapes can be inscribed in the circle,
there’s absolutely no necessity for my thinking that
all quadrilaterals are among them. Indeed, I can’t
even think that all quadrilaterals are among them,
since I’ve resolved to accept only what I clearly and
distinctly understand. Thus my false suppositions
differ greatly from the true ideas implanted in me,
the first and foremost of which is my idea of God.
In many ways, I see that this idea is not a figment of
my thought, but the image of a real and immutable
nature. For one thing, God is the only thing that I
can think of whose existence belongs to its essence.
even when I clung most tightly to objects of sense,
I regarded truths about shape and number—truths
of arithmetic, geometry, and pure mathematics—
as more certain than any others.
But, if anything whose idea I can draw from my
thought must in fact have everything that I clearly
and distinctly grasp it to have, can’t I derive from
this a proof of God’s existence? Surely, I find the
idea of God, a supremely perfect being, in me no
less clearly than I find the ideas of figures and numbers. And I understand as clearly and distinctly that
eternal existence belongs to His nature as that the
things which I demonstrate of a figure or number
belong to the nature of the figure or number. Accordingly, even if what I have thought up in the
past few days hasn’t been entirely true, I ought to
be at least as certain of God’s existence as I used to
be of the truths of pure mathematics.
At first, this reasoning may seem unclear and
fallacious. Since I’m accustomed to distinguishing
existence from essence in other cases, I find it easy
to convince myself that I can separate God’s existence from His essence and hence that I can think
of God as nonexistent. But, when I pay more careful attention, it’s clear that I can no more separate
God’s existence from His essence than a triangle’s
angles equaling two right angles from the essence
of the triangle, or the idea of a valley from the idea
of a mountain. It’s no less impossible to think that
God (the supremely perfect being) lacks existence
(a perfection) than to think that a mountain lacks
a valley.
Well, suppose that I can’t think of God without existence, just as I can’t think of a mountain
without a valley. From the fact that I can think of
a mountain with a valley, it doesn’t follow that a
mountain exists in the world. Similarly, from the
fact that I can think of God as existing, it doesn’t
seem to follow that He exists. For my thought
doesn’t impose any necessity on things. It may be
that, just as I can imagine a winged horse when no
such horse exists, I can ascribe existence to God
when no God exists.
No, there is a fallacy here. From the fact that
I can’t think of a mountain without a valley it follows, not that the mountain and valley exist, but
only that whether they exist or not they can’t be
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angles: I can’t fail to believe this as long as I pay
attention to its demonstration. But, if I were ignorant of God, I might come to doubt its truth as
soon as my mind’s eye turned away from its demonstration, even if I recalled having once grasped
it clearly. For I could convince myself that I’ve
been so constructed by nature that I sometimes err
about what I believe myself to grasp most plainly—
especially if I remember that, having taken many
things to be true and certain, I had later found
grounds on which to judge them false.
But now I grasp that God exists, and I understand both that everything else depends on Him
and that He’s not a deceiver. From this, I infer
that everything I clearly and distinctly grasp must
be true. Even if I no longer pay attention to the
grounds on which I judged God to exist, my recollection that I once clearly and distinctly knew Him
to exist ensures that no contrary ground can be
produced to push me towards doubt. About God’s
existence, I have true and certain knowledge. And I
have such knowledge, not just about this one thing,
but about everything else that I remember having
proven, like the theorems of geometry. For what
can now be said against my believing these things?
That I am so constructed that I always err? But I
now know that I can’t err about what I clearly understand. That much of what I took to be true and
certain I later found to be false? But I didn’t grasp
any of these things clearly and distinctly; ignorant
of the true standard of truth, I based my belief on
grounds that I later found to be unsound. Then
what can be said? What about the objection (which
I recently used against myself) that I may be dreaming and that the things I’m now experiencing may
be as unreal as those that occur to me in sleep? No,
even this is irrelevant. For, even if I am dreaming,
everything that is evident to my understanding
must be true.
Thus I plainly see that the certainty and truth
of all my knowledge derives from one thing: my
thought of the true God. Before I knew Him, I
couldn’t know anything else perfectly. But now I
can plainly and certainly know innumerable things,
not only about God and other mental beings, but
also about the nature of physical objects, insofar as
it is the subject-matter of pure mathematics.
For another thing, I can’t conceive of there being
two or more such Gods, and, having supposed that
one God now exists, I see that He has necessarily
existed from all eternity and will continue to exist
into eternity. And I also perceive many other things
in God that I can’t diminish or alter.
But, whatever proof I offer, it always comes
back to the fact that I am only convinced of what
I grasp clearly and distinctly. Of the things that I
grasp in this way, some are obvious to everyone.
Some are discovered only by those who examine
things more closely and search more carefully,
but, once these things have been discovered, they
are regarded as no less certain than the others.
That the square on the hypotenuse of a right triangle equals the sum of the squares on the other
sides is not as readily apparent as that the hypotenuse subtends the greatest angle, but, once it
has been seen, it is believed just as firmly. And,
when I’m not overwhelmed by prejudices and
my thoughts aren’t besieged by images of sensible
things, there surely is nothing that I know earlier
or more easily than facts about God. For what is
more self-evident than there is a supreme entity—
that God, the only thing whose existence belongs
to His essence, exists?
While I need to pay careful attention in order
to grasp this, I’m now as certain of it as of anything
that seems most certain. In addition, I now see that
the certainty of everything else so depends on it
that, if I weren’t certain of it, I couldn’t know anything perfectly.
Of course, my nature is such that, when I grasp
something clearly and distinctly, I can’t fail to
believe it. But my nature is also such that I can’t
permanently fix my attention on a single thing so
as always to grasp it clearly, and memories of previous judgments often come to me when I am no
longer attending to the grounds on which I originally made them. Accordingly, if I were ignorant
of God, arguments could be produced that would
easily overthrow my opinions, and I therefore
would have unstable and changing opinions rather
than true and certain knowledge. For example,
when I consider the nature of the triangle, it seems
plain to me—steeped as I am in the principles of
geometry—that its three angles equal two right
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and discover that the answer is yes. With respect
to these geometrical properties, there are truths.*
And these, remember, are the very properties that
determine the essence of material things.
Since the idea of a material thing is the idea of
something extended, and since extended things can
be treated geometrically, it follows that the idea of
a material thing is clear and distinct. Material substances have an essence or nature that would make
a science of them a possibility—if only we could be
assured that they exist. And we know that such a
science is a possibility merely from an examination
of their ideas. So, provided we can discover a proof
that some formal reality corresponds to the subjective reality of our ideas of material things, we can
have a science of material things. In this way, then,
he hopes to give a metaphysical foundation to his
mechanistic physics.
The discovery that certain ideas have a nature or
essence of their own, quite independent of our inventions, also supplies Descartes with material for a third
proof of God’s existence.† If we simply pay close attention to what is necessarily involved in our idea of
what God is (his essence or nature), we can discover,
Descartes argues, that God is (that he exists). God’s
existence is included in his essence. Notice that,
unlike the first two arguments, this is not a causal
proof. In its bare essentials, it looks like this:
1. God, by definition, is a being of infinite
2. Existence is a perfection (that is, no being could
be perfect that lacked it).
3. So God exists.
Commentary and Questions
This brief meditation is a transition to the more important sixth meditation. Though Descartes says at
the beginning that he wants to investigate whether
we can know anything about material things (so far,
only God and the soul are known), he doesn’t solve
that problem here. But he does take a significant
step toward its solution. Along the way, he discovers a third proof that God exists.
Again we find the typical Cartesian strategy
at work. He wants to know whether material
things exist independent of himself. How can
he proceed? He can’t just look to see because he
has put the testimony of the senses in doubt. So
he must consider more carefully the idea of material things, which is all that is available to him. And
again he finds that some of these ideas are confused
and obscure, while others are clear and distinct.
The latter are those of extension, duration, and
movement—the qualities that can be treated geometrically or mathematically. Material things, if
there are any, are essentially extended volumes.*
Once we are clear about their essence, it makes
sense to inquire about their existence; and that is the
subject of Meditation VI.
Note that these mathematical ideas are not
just imaginary inventions. You cannot put them
together any way you like, as you can construct
fantastic creatures by combining heads, bodies,
and hides at will. You may not yet know whether
there are any triangular things outside yurself, but
the idea of a triangle “can’t be said to be nothing”
(p. 388). It has a nature that is “immutable and eternal.” This nature does not depend on me.
The point can be put in this way. Suppose you
imagine a creature with wings covered with scales,
a long furry tail, six legs, and an elephantlike nose
covered with spikes. Then someone asks you, does
this creature have claws? You will have to invent the
answer. You cannot discover it. But if you imagine a triangle and someone asks you whether the
interior angles equal two right angles, you do not
have to invent an answer. You could investigate
*Review the discussion of the bit of wax in Meditation II
and on p. 375.
*Socrates thinks that we can never be taught anything
other than what we in some sense already know; what we
call “learning” is in fact just remembering. (See p. 169.)
Descartes alludes to this doctrine here; in discovering the
properties of a triangle you are “noticing for the first time
something that had long been in [you] without [your] having
turned [your] mind’s eye towards it.” Descartes is not, however, committed to the Socratic doctrine of the preexistence
of the soul as an explanation of this phenomenon, since he
thinks God’s creation of a soul possessing certain innate ideas
will suffice. †This proof is a version of the ontological argument first
worked out by Anselm of Canterbury in the eleventh century. See Chapter 15.
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When I want to think of a chiliagon, I understand
that it is a figure with a thousand sides as well as
I understand that a triangle is a figure with three,
but I can’t imagine its sides or “look” at them as
though they were present. Being accustomed to
using images when I think about physical objects, I
may confusedly picture some figure to myself, but
this figure obviously is not a chiliagon—for it in
no way differs from what I present to myself when
thinking about a myriagon or any other many sided
figure, and it doesn’t help me to discern the properties that distinguish chiliagons from other polygons. If it’s a pentagon that is in question, I can
understand its shape, as I can that of the chiliagon,
without the aid of mental images. But I can also
get a mental image of the pentagon by directing
my mind’s eye to its five lines and to the area that
they bound. And it’s obvious to me that getting
this mental image requires a special mental effort
different from that needed for understanding—a
special effort which clearly reveals the difference
between having a mental image and having a pure
It also seems to me that my power of having
mental images, being distinct from my power of
understanding, is not essential to my self or, in
other words, to my mind—for, if I were to lose
this ability, I would surely remain the same thing
that I now am. And it seems to follow that this
ability depends on something distinct from me.
If we suppose that there is a body so associated
with my mind that the mind can “look into” it at
will, it’s easy to understand how my mind might
get mental images of physical objects by means
of my body. If there were such a body, the mode
of thinking that we call imagination would differ
from pure understanding in only one way: when
the mind understood something, it would turn
“inward” and view an idea that it found in itself,
but, when it had mental images, it would turn to
the body and look at something there which resembled an idea that it had understood by itself
or had grasped by sense. As I’ve said, then, it’s
easy to see how I get mental images, if we supposed that my body exists. And, since I don’t have
in mind any other equally plausible explanation
of my ability to have mental images, I conjecture
Q40. Is the argument valid?
Q41. Can the premises be questioned?
This last proof of God’s existence allows Descartes to lay to rest a final worry that has been tormenting him. You really cannot help believing,
he suggests, that your clear and distinct thoughts
are true—while you are thinking them. But later
you may not be so sure! You may then think you
were dreaming what earlier seemed so certain. But
now this worry can be dealt with. And Meditation V
closes on a note of reassurance.
Q42. How are the dream and demon worries finally
disposed of?
Q43. Can an atheist do science? (See the last
Meditation VI: On the Existence
of Material Objects and the Real
Distinction of Mind from Body
It remains for me to examine whether material
objects exist. Insofar as they are the subject of
pure mathematics, I now know at least that they
can exist, because I grasp them clearly and distinctly. For God can undoubtedly make whatever
I can grasp in this way, and I never judge that
something is impossible for Him to make unless
there would be a contradiction in my grasping the
thing distinctly. Also, the fact that I find myself
having mental images when I turn my attention to
physical objects seems to imply that these objects
really do exist. For, when I pay careful attention
to what it is to have a mental image, it seems to
me that it’s just the application of my power of
thought to a certain body which is immediately
present to it and which must therefore exist.
To clarify this, I’ll examine the difference between having a mental image and having a pure
understanding. When I have a mental image of a
triangle, for example, I don’t just understand that
it is a figure bounded by three lines; I also “look at”
the lines as though they were present to my mind’s
eye. And this is what I call having a mental image.
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thought—physical objects from which the ideas
came. For I found that these ideas came to me independently of my desires so that, however much
I tried, I couldn’t sense an object when it wasn’t
present to an organ of sense or fail to sense one
when it was present. And, since the ideas that
I grasped by sense were much livelier, more explicit, and (in their own way) more distinct than
those I deliberately created or found impressed in
my memory, it seemed that these ideas could not
have come from me and thus that they came from
something else. Having no conception of these
things other than that suggested by my sensory
ideas, I could only think that the things resembled
the ideas. Indeed, since I remembered using my
senses before my reason, since I found the ideas
that I created in myself to be less explicit than those
grasped by sense, and since I found the ideas that I
created to be composed largely of those that I had
grasped by sense, I easily convinced myself that I
didn’t understand anything at all unless I had first
sensed it.
I also had some reason for supposing that
a certain physical object, which I viewed as belonging to me in a special way, was related to
me more closely than any other. I couldn’t be
separated from it as I could from other physical objects; I felt all of my emotions and desires
in it and because of it; and I was aware of pains
and pleasant feelings in it but in nothing else. I
didn’t know why sadness goes with the sensation
of pain or why joy goes with sensory stimulation. I didn’t know why the stomach twitchings
that I call hunger warn me that I need to eat or
why dryness in my throat warns me that I need
to drink. Seeing no connection between stomach
twitchings and the desire to eat or between the
sensation of a pain-producing thing and the consequent awareness of sadness, I could only say that
I had been taught the connection by nature. And
nature seems also to have taught me everything
else that I knew about the objects of sensation—
for I convinced myself that the sensations came to
me in a certain way before having found grounds
on which to prove that they did.
But, since then, many experiences have shaken
my faith in the senses. Towers that seemed round
that physical objects probably do exist. But this
conjecture is only probable. Despite my careful and thorough investigation, the distinct idea
of bodily nature that I get from mental images
does not seem to have anything in it from which
the conclusion that physical objects exist validly
Besides having a mental image of the bodily
nature that is the subject-matter of pure mathematics, I have mental images of things which are
not so distinct—things like colors, sounds, flavors,
and pains. But I seem to grasp these things better
by sense, from which they seem to come (with the
aid of memory) to the understanding. Thus, to
deal with these things more fully, I must examine
the senses and see whether there is anything in the
mode of awareness that I call sensation from which
I can draw a conclusive argument for the existence
of physical objects.
First, I’ll remind myself of the things that I
believed really to be as I perceived them and of
the grounds for my belief. Next, I’ll set out the
grounds on which I later called this belief into
doubt. And, finally, I’ll consider what I ought to
think now.
To begin with, I sensed that I had a head, hands,
feet, and the other members that make up a human
body. I viewed this body as part, or maybe even as
all, of me. I sensed that it was influenced by other
physical objects whose effects could be either
beneficial or harmful. I judged these effects to be
beneficial to the extent that I felt pleasant sensations and harmful to the extent that I felt pain.
And, in addition to sensations of pain and pleasure,
I sensed hunger, thirst, and other such desires—
and also bodily inclinations towards cheerfulness, sadness, and other emotions. Outside me,
I sensed, not just extension, shape, and motion,
but also hardness, hotness, and other qualities detected by touch. I also sensed light, color, odor,
taste, and sound—qualities by whose variation
I distinguished such things as the sky, earth, and
sea from one another.
In view of these ideas of qualities (which presented themselves to my thought and were all that
I really sensed directly), I had some reason for
believing that I sensed objects distinct from my
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separately.) Accordingly, from the fact that I have
gained knowledge of my existence without noticing anything about my nature or essence except
that I am a thinking thing, I can rightly conclude
that my essence consists solely in the fact that I
am a thinking thing. It’s possible (or, as I will say
later, it’s certain) that I have a body which is very
tightly bound to me. But, on the one hand, I have a
clear and distinct idea of myself insofar as I am just
a thinking and unextended thing, and, on the other
hand, I have a distinct idea of my body insofar as it
is just an extended and unthinking thing. It’s certain, then, that I am really distinct from my body
and can exist without it.
In addition, I find in myself abilities for special modes of awareness, like the abilities to have
mental images and to sense. I can clearly and distinctly conceive of my whole self as something
that lacks these abilities, but I can’t conceive of
the abilities’ existing without me, or without an
understanding substance in which to reside. Since
the conception of these abilities includes the conception of something that understands, I see that
these abilities are distinct from me in the way that a
thing’s properties are distinct from the thing itself.
I recognize other abilities in me, like the ability
to move around and to assume various postures.
These abilities can’t be understood to exist apart
from a substance in which they reside any more
than the abilities to imagine and sense, and they
therefore cannot exist without such a substance.
But it’s obvious that, if these abilities do exist, the
substance in which they reside must be a body or
extended substance rather than an understanding
one—for the clear and distinct conceptions of these
abilities contain extension but not understanding.
There is also in me, however, a passive ability
to sense—to receive and recognize ideas of sensible
things. But, I wouldn’t be able to put this ability to
use if there weren’t, either in me or in something
else, an active power to produce or make sensory
ideas. Since this active power doesn’t presuppose
understanding, and since it often produces ideas in
me without my cooperation and even against my
will, it cannot exist in me. Therefore, this power
must exist in a substance distinct from me. And,
for reasons that I’ve noted, this substance must
from a distance sometimes looked square from
close up, and huge statues on pediments sometimes
didn’t look big when seen from the ground. In innumerable such cases, I found the judgments of the
external senses to be wrong. And the same holds
for the internal senses. What is felt more inwardly
than pain? Yet I had heard that people with amputated arms and legs sometimes seem to feel pain
in the missing limb, and it therefore didn’t seem
perfectly certain to me that the limb in which I feel
a pain is always the one that hurts. And, to these
grounds for doubt, I’ve recently added two that
are very general: First, since I didn’t believe myself
to sense anything while awake that I couldn’t also
take myself to sense in a dream, and since I didn’t
believe that what I sense in sleep comes from objects outside me, I didn’t see why I should believe
what I sense while awake comes from such objects.
Second, since I didn’t yet know my creator (or,
rather, since I supposed that I didn’t know Him),
I saw nothing to rule out my having been so designed by nature that I’m deceived even in what
seems most obviously true to me.
And I could easily refute the reasoning by which
I convinced myself of the reality of sensible things.
Since my nature seemed to impel me toward many
things that my reason rejected, I didn’t believe
that I ought to have much faith in nature’s teachings. And, while my will didn’t control my sense
perceptions, I didn’t believe it to follow that these
perceptions came from outside me, since I thought
that the ability to produce these ideas might be in
me without my being aware of it.
Now that I’ve begun to know myself and my
creator better, I still believe that I oughtn’t blindly
to accept everything that I seem to get from the
senses. Yet I no longer believe that I ought to call
it all into doubt.
In the first place, I know that everything that I
clearly and distinctly understand can be made by
God to be exactly as I understand it. The fact that
I can clearly and distinctly understand one thing
apart from another is therefore enough to make
me certain that it is distinct from the other, since
the things could be separated by God if not by
something else. (I judge the things to be distinct
regardless of the power needed to make them exist
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Through sensations like pain, hunger, and
thirst, nature also teaches me that I am not present
in my body in the way that a sailor is present in his
ship. Rather, I am very tightly bound to my body
and so “mixed up” with it that we form a single
thing. If this weren’t so, I—who am just a thinking thing—wouldn’t feel pain when my body was
injured; I would perceive the injury by pure understanding in the way that a sailor sees the leaks in
his ship with his eyes. And, when my body needed
food or drink, I would explicitly understand that
the need existed without having the confused
sensations of hunger and thirst. For the sensations of thirst, hunger, and pain are just confused
modifications of thought arising from the union and
“mixture” of mind and body.
Also, nature teaches me that there are other
physical objects around my body—some that
I ought to seek and others that I ought to avoid.
From the fact that I sense things like colors, sound,
odors, flavors, temperatures, and hardnesses, I correctly infer that sense perceptions come from physical objects that vary as widely (though perhaps not
in the same way) as the perceptions do. And, from
the fact that some of these perceptions are pleasant
while others are unpleasant, I infer with certainty
that my body—or, rather, my whole self which
consists of a body and a mind—can be benefited
and harmed by the physical objects around it.
There are many other things that I seem to
have been taught by nature but that I have really
accepted out of a habit of thoughtless judgment.
These things may well be false. Among them are
the judgments that a space is empty if nothing in
it happens to affect my senses; that a hot physical
object has something in it resembling my idea of
heat; that a white or green thing has in it the same
whiteness or greenness that I sense; that a bitter or
sweet thing has in it the same flavor that I taste; that
stars, towers, and other physical objects have the
same size and shape that they present to my senses;
and so on.
If I am to avoid accepting what is indistinct
in these cases, I must more carefully explain my
use of the phrase “taught by nature.” In particular, I should say that I am now using the term
“nature” in a narrower sense than when I took it
contain, either formally or eminently, all the reality that is contained subjectively in the ideas that
the power produces. Either this substance is a physical object (a thing of bodily nature that contains
formally the reality that the idea contains subjectively), or it is God or one of His creations that is
higher than a physical object (something that contains this reality eminently). But, since God isn’t a
deceiver, it’s completely obvious that He doesn’t
send these ideas to me directly or by means of a
creation that contains their reality eminently rather
than formally. For, since He has not given me any
ability to recognize that these ideas are sent by Him
or by creations other than physical objects, and
since He has given me a strong inclination to believe that the ideas come from physical objects, I
see no way to avoid the conclusion that He deceives
me if the ideas are sent to me by anything other
than physical objects. It follows that physical objects exist. These objects may not exist exactly as I
comprehend them by sense; in many ways, sensory
comprehension is obscure and confused. But these
objects must at least have in them everything that
I clearly and distinctly understand them to have—
every general property within the scope of pure
But what about particular properties, such
as the size and shape of the sun? And what about
things that I understand less clearly than mathematical properties, like light, sound, and pain?
These are open to doubt. But, since God isn’t a
deceiver, and since I therefore have the God-given
ability to correct any falsity that may be in my beliefs, I have high hopes of finding the truth about
even these things. There is undoubtedly some
truth in everything I have been taught by nature—
for, when I use the term “nature” in its general
sense, I refer to God Himself or to the order that
He has established in the created world, and, when
I apply the term specifically to my nature, I refer to
the collection of everything that God has given me.
Nature teaches me nothing more explicitly,
however, than that I have a body which is hurt
when I feel pain, which needs food or drink when
I experience hunger or thirst, and so on. Accordingly, I ought not to doubt that there is some truth
to this.
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I’ve already explained how it can be that, despite God’s goodness, my judgments can be false.
But a new difficulty arises here—one having to
do with the things that nature presents to me as
desirable or undesirable and also with the errors
that I seem to have found in my internal sensations. One of these errors seems to be committed, for example, when a man is fooled by some
food’s pleasant taste into eating poison hidden in
that food. But surely, in this case, what the man’s
nature impels him to eat is the good tasting food,
not the poison of which he knows nothing. We
can draw no conclusion except that his nature isn’t
omniscient, and this conclusion isn’t surprising.
Since a man is a limited thing, he can only have
limited perfections.
Still, we often err in cases in which nature
does impel us. This happens, for example, when
sick people want food or drink that would quickly
harm them. To say that these people err as a result
of the corruption of their nature does not solve the
problem—for a sick man is no less a creation of
God than a well one, and it seems as absurd to suppose that God has given him a deceptive nature.
A clock made of wheels and weights follows the
natural laws just as precisely when it is poorly
made and inaccurate as when it does everything
that its maker wants. Thus, if I regard a human
body as a machine made up of bones, nerves, muscles, veins, blood, and skin such that even without
a mind it would do just what it does now (except
for things that require a mind because they are
controlled by the will), it’s easy to see that what
happens to a sick man is no less “natural” than what
happens to a well one. For instance, if a body suffers from dropsy, it has a dry throat of the sort
that regularly brings the sensation of thirst to the
mind, the dryness disposes the nerves and other
organs to drink, and the drinking makes the illness
worse. But this is just as natural as when a similar
dryness of throat moves a person who is perfectly
healthy to take a drink that is beneficial. Bearing in
mind my conception of a clock’s use, I might say
that an inaccurate clock departs from its nature,
and, similarly, viewing the machine of the human
body as designed for its usual motions, I can say
that it drifts away from its nature if it has a dry
to refer to the whole complex of what God has
given me. This complex includes much having to
do with my mind alone (such as my grasp of the
fact that what is done cannot be undone and of
the rest of what I know by the light of nature)
which does not bear on what I am now saying.
And the complex also includes much having to
do with my body alone (such as its tendency to
go downward) with which I am not dealing now.
I’m now using the term “nature” to refer only to
what God has given me insofar as I am a composite of mind and body. It is this nature that teaches
me to avoid that which occasions painful sensations, to seek that which occasions pleasant sensations, and so on. But this nature seems not to
teach me to draw conclusions about external objects from sense perceptions without first having
examined the matter with my understanding—
for true knowledge of external things seems to
belong to the mind alone, not to the composite
of mind and body.
Thus, while a star has no more effect on my
eye than a flame, this does not really produce a
positive inclination to believe that the star is as
small as the flame; for my youthful judgment about
the size of the flame, I had no real grounds. And,
while I feel heat when I approach a fire and pain
when I draw nearer, I have absolutely no reason
for believing that something in the fire resembles
the heat, just as I have no reason for believing that
something in the fire resembles the pain; I only
have reason for believing that there is something
or other in the fire that produces the feelings of
heat and pain. And, although there may be nothing
in a given region of space that affects my senses, it
doesn’t follow that there aren’t any physical objects in that space. Rather I now see that, on these
matters and others, I used to pervert the natural
order of things. For, while nature has given sense
perceptions to my mind for the sole purpose of
indicating what is beneficial and what harmful to
the composite of which my mind is a part, and
while the perceptions are sufficiently clear and
distinct for that purpose, I used these perceptions
as standards for identifying the essence of physical
objects—an essence which they only reveal obscurely and confusedly.
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it presents the same thing to the mind, regardless
of what is happening in the rest of the body (as is
shown by innumerable experiments that I need not
review here).
In addition, I notice that the nature of body is
such that, if a first part can be moved by a second
that is far away, the first part can be moved in
exactly the same way by something between
the first and second without the second part’s
being affected. For example, if A, B, C, and D
are points on a cord, and if the first point (A)
can be moved in a certain way by a pull on the
last point (D), then A can be moved in the same
way by a pull on one of the middle points (B or
C) without D’s being moved. Similarly, science
teaches me that, when my foot hurts, the sensation of pain is produced by nerves distributed
throughout the foot which extend like cords
from there to the brain. When pulled in the foot,
these nerves pull the central parts of the brain to
which they are attached, moving those parts in
ways designated by nature to present the mind
with the sensation of a pain “in the foot.” But,
since these nerves pass through the shins, thighs,
hips, back, and neck on their way from foot to
brain, it can happen that their being touched in
the middle, rather than at the end of the foot,
produces the same motion in the brain as when
the foot is hurt and, hence, that the mind feels
the same pain “in the foot.” And the point holds
for other sensations as well.
Finally, I notice that, since only one sensation
can be produced by a given motion of the part of
the brain that directly affects the mind, the best
conceivable sensation for it to produce is the one
that is most often useful for the maintenance of
the healthy man. Experience teaches that all the
sensations put in us by nature are of this sort and
therefore that everything in our sensations testifies
to God’s power and goodness. For example, when
the nerves in the foot are moved with unusual
violence, the motion is communicated through
the middle of the spine to the center of the brain,
where it signals the mind to sense a pain “in the
foot.” This urges the mind to view the pain’s
cause as harmful to the foot and to do what it can
to remove that cause. Of course, God could have
throat when drinking will not help to maintain it.
I should note, however, that the sense in which I
am now using the term “nature” differs from that
in which I used it before. For, as I have just used
the term “nature,” the nature of a man (or clock)
is something that depends on my thinking of the
difference between a sick and a well man (or of
the difference between a poorly made and a wellmade clock)—something regarded as extrinsic to
the things. But, when I used “nature” before, I referred to something which is in things and which
therefore has some reality.
It may be that we just offer an extrinsic description of a body suffering from dropsy when, noting
that it has a dry throat but doesn’t need to drink,
we say that its nature is corrupted. Still, the description is not purely extrinsic when we say that
a composite or union of mind and body has a corrupted nature. There is a real fault in the composite’s nature, for it is thirsty when drinking would
be harmful. It therefore remains to be asked why
God’s goodness doesn’t prevent this nature’s being
To begin the answer, I’ll note that mind differs importantly from body in that body is by its
nature divisible while mind is indivisible. When I
think about my mind—or, in other words, about
myself insofar as I am just a thinking thing—I can’t
distinguish any parts in me; I understand myself
to be a single, unified thing. Although my whole
mind seems united to my whole body, I know that
cutting off a foot, arm, or other limb would not
take anything away from my mind. The abilities to
will, sense, understand, and so on can’t be called
parts, since it’s one and the same mind that wills,
senses, and understands. On the other hand,
whenever I think of a physical or extended thing,
I can mentally divide it, and I therefore understand that the object is divisible. This single fact
would be enough to teach me that my mind and
body are distinct, if I hadn’t already learned that
in another way.
Next, I notice that the mind isn’t directly affected by all parts of the body, but only by the
brain—or maybe just by the small part of the
brain containing the so-called “common sense.”
Whenever this part of the brain is in a given state,
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what the senses daily show me is unreal. I should
reject the exaggerated doubts of the past few days
as ridiculous. This is especially true of the chief
ground for these doubts—namely, my inability
to distinguish dreaming from being awake. For I
now notice that dreaming and being awake are importantly different: the events in dreams are not
linked by memory to the rest of my life like those
that happen while I am awake. If, while I’m awake,
someone were suddenly to appear and then immediately to disappear without my seeing where he
came from or went to (as happens in dreams), I
would justifiably judge that he was not a real man
but a ghost—or, better an apparition created in
my brain. But, if I distinctly observe something’s
source, its place, and the time at which I learn
about it, and if I grasp an unbroken connection
between it and the rest of my life, I’m quite sure
that it is something in my waking life rather than
in a dream. And I ought not to have the slightest
doubt about the reality of such things if I have examined them with all my senses, my memory, and
my understanding without finding any conflicting
evidence. For, from the fact that God is not a deceiver, it follows that I am not deceived in any
case of this sort. Since the need to act does not
always allow time for such a careful examination,
however, we must admit the likelihood of men’s
erring about particular things and acknowledge
the weakness of our nature.
Commentary and Questions
We now know what the essence of material things
is: To be such a thing is to be extended in space
in three dimensions, to have shape and size, to
endure, and to be movable and changeable in these
dimensions. This is what a material thing would
be—if there were any. At last we face the haunting
question: Are there any?
The first thing to note is that they can exist.
Q44. What is Descartes’ reason for thinking this?
If, moreover, we examine our images of material things, it seems that the imagination produces
these images by turning “to the body” and looking
so designed man’s nature that the same motion of
the brain presented something else to the mind,
like the motion in the brain, or the motion in the
foot, or a motion somewhere between the brain
and foot. But no alternative to the way things are
would be as conducive to the maintenance of the
body. Similarly, when we need drink, the throat
becomes dry, the dryness moves the nerves of the
throat thereby moving the center of the brain, and
the brain’s movements cause the sensation of thirst
in the mind. It’s the sensation of thirst that is produced, because no information about our condition is more useful to us than that we need to get
something to drink in order to remain healthy.
And the same is true in other cases.
This makes it completely obvious that, despite God’s immense goodness, the nature of man
(whom we now view as a composite of mind and
body) cannot fail to be deceptive. For, if something produces the movement usually associated
with an injured foot in the nerve running from
foot to brain or in the brain itself rather than in
the foot, a pain is felt as if “in the foot.” Here
the senses are deceived by their nature. Since this
motion in the brain must always bring the same
sensation to mind, and since the motion’s cause
is something hurting the foot more often than
something elsewhere, it’s in accordance with
reason that the motion always presents the mind
a pain in the foot rather than elsewhere. And, if
dryness of the throat arises, not (as usual) from
drink’s being conducive to the body’s health, but
(as happens in dropsy) from some other cause,
it’s much better that we are deceived on this occasion than that we are generally deceived when
our bodies are sound. And the same holds for
other cases.
In addition to helping me to be aware of
the errors to which my nature is subject, these
reflections help me readily to correct or avoid
these errors. I know that sensory indications of
what is good for my body are more often true than
false; I can almost always examine a given thing
with several senses; and I can also use my memory
(which connects the present to the past) and my
understanding (which has now examined all the
causes of error). Hence, I need no longer fear that
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of material things, which he arrived at in the fifth
Here, in outline, is his proof for the distinctness
of soul from body.
1. God can create anything that I can clearly and
distinctly conceive—there being no impossibility in it.
2. If God can create one thing independent of another, the first thing is distinct from the second.
3. I have a clear and distinct idea of my essence as
a thinking thing.
4. So God can create a thinking thing (a soul) independent of a body.
5. I also have a clear and distinct idea of my body
as an extended thing—its essence.
6. So God can create a body independent of a soul.
7. So my soul is a reality distinct from my body.
8. So I, as a thinking thing (soul), can exist without my body.
Q46. How sound is this argument? What are the weak
points, if any?
Q47. Is there a tension between the conclusion of this
argument and Descartes’ assertion (p. 395) that
you are not in your body the way a sailor is in
his ship?*
Descartes’ proof for the reality of material things
goes roughly like this:
1. I have a “strong inclination” to believe in the
reality of the material (extended) things that I
seem to sense. (To put it another way, their independent reality seems to be one of the things
I am “taught by nature.”)
2. God must have created me with this inclination.
3. If material things do not exist independently,
then God is a deceiver.
4. But God is not a deceiver.
5. So material things exist with those properties I
conceive to be essential to them.
Q48. Evaluate the soundness of this argument.
“at something there” (p. 392). It is as though a
representation of a triangle were physically stored
in the body (or brain); and imagination is looking
not at a real triangular thing, but at that stored
representation. Because we can undoubtedly
form mental images, it certainly seems as though
some material things exist—namely, our bodies.
But to make this clearer, Descartes draws a
sharp distinction between imagining something
and conceiving it.
Q45. How does the example comparing the triangle
with the chiliagon help to clarify this distinction?
(See p. 392.)
We still have no proof, of course, that there are
any bodies. But again, progress has been made; for
we now have an account of how one of the faculties
of the mind works—on the assumption that there
really are bodies. If we can find a proof of this assumption, it will “fit” with what we know about
our mental capacities.
Descartes now turns from imagining to sensing.
On pages 393–394, he reviews again his reasons
for confidence in the senses and then his reasons
for doubt.* At the end of this review he concludes
again that what he is taught “by nature” does not
deserve much credence.
However, the situation is now very different
from that of the first meditation. For now he knows
that God exists and is not a deceiver. And in short
order Descartes offers proofs that the soul is distinct from the body and that material things exist.
Both of these depend on clear ideas of the essence
*In the course of this review he paraphrases one of the
basic principles of Thomas Aquinas, who derives it from Aristotle: There is no idea in the intellect, which was not previously in the senses. This is, for instance, the foundation for
Aquinas’s rejection of the ontological argument (see p. 319).
Descartes allows that this principle is superficially plausible,
but in the light of his skeptical doubts he considers it naive.
Not only do we know that we have ideas before we know
we have senses, we know that some of these ideas must be
innate—that is, they could not plausibly be derived from
sensible experience. Such are the ideas of thing, thought,
truth, and God.
*Compare the use that Aquinas makes of this same
image, p. 327.
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Let us sum up several key features of his thought
and then indicate where certain problems crop up.
A New Ideal for Knowledge
One commentator says of the Cartesian revolution
that it “stands for the substitution of free inquiry for
submission to authority, for the rejection of Faith
without reason for faith in reason, and the replacement of Faith by Demonstration.”6
Though Descartes is far from trying to reject religious belief
(indeed, he thinks he can rationally justify its two
most important parts, God and the soul), in the end
everything comes down to what the rational mind
finds clear and distinct enough to be indubitable.
Nothing else will be accepted, regardless of its antiquity or traditional claims to authority. We each
contain within ourselves the criterion for truth and
knowledge. This radical individualism is qualified
only by the conviction that rationality is the same
for every individual (just as mathematics is the same
for all). No longer can we put the responsibility for
deciding what to believe on someone else, whether
priest, pope, or king. It lies squarely on each of us.
Moreover, the ideal for such belief is the clarity and certainty of mathematics. Probability or
plausibility is not enough. Being vaguely right is not
enough. The habits of thought developed in us by
nature are not enough. By analysis we can resolve
problems into their simple elements; by intuition
we can see their truth; and by demonstration we can
move to necessary consequences. Knowledge has the
structure of an axiomatic system. All this is possible.
Anything less is unacceptable. To be faithful to this
ideal is to free oneself from error and to attain truth.
In all this Descartes deserves his reputation as
Prince of the Rationalists.* The ultimate court of
appeal is reason—the light of nature. We ought
to rely on intellect rather than sense, on intuition
and deduction rather than imagination; “for true
At this point, Descartes has, he thinks, defeated
both skepticism and solipsism. He has delineated
the basic structure of reality: God, souls, and material things. Reality, then, is composed of infinite
substance and two kinds of finite substances—
thinking and extended. The bridge has been built.
Knowledge has been shown to be possible. Physics
has been supplied with a foundation in metaphysics. And all this with a certainty that rivals that of
The rest of Meditation VI attends to a few details
that are left.
Q49. Compare what Descartes says on p. 395
with Galileo’s view of “secondary qualities”
(pp. 356–357).
Q50. If the senses present external things in such an
inadequate way, what use are they?
Q51. How are we to account for certain errors the
senses seem to lead us to—such as the pain in an
amputated limb or the desire of a person with
dropsy (edema) to drink?
Q52. What is the final disposition of the problem
arising from dreams?
What Has Descartes Done?
It is possible to argue whether Descartes is the last
of the medievals or the first of the moderns. Like
most such arguments about transitional figures,
there is truth on both sides. But that both philosophy and our general view of the world have
been different ever since is indisputable. Descartes
develops a philosophy that reflects the newly developing sciences and, in turn, gives them a legitimacy they otherwise lack. A measure of his lasting
influence is the fact that a significant part of philosophy since World War I has been devoted to showing that he was crucially wrong about some basic
things (which would not be worth doing unless his
influence was still powerfully felt).* Descartes is
our ancestor.
*Among the critics are C. S. Peirce, Martin Heidegger,
Ludwig Wittgenstein, Willard Quine, Richard Rorty, and
Daniel Dennett. See the chapters on their philosophies.
*Though (almost) all philosophers try to reach their
conclusions rationally, a rationalist is one who emphasizes
the exclusive role of reason in the formation of knowledge.
For one of Descartes’ most distinguished predecessors in this
tradition, see the discussion of the pre-Socratic thinker, Parmenides, in Chapter 2.
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The Place of Humans in the World of Nature
Descartes is intent on legitimizing the new science.
But what place is there for us in the universe of the
new physics? Could we, too, be mere cogs in this
universal machine? We assume that we have purposes and act to realize certain values. But where is
there room for purposes and values in this mechanistic world? Is our assumption just an illusion?
We assume that we can make a difference in the
outcome of physical processes. But if the world is a
closed mechanism, how can this be? We experience
ourselves as conscious beings, aware of ourselves
and the world around us. But can a machine be conscious? These are very contemporary questions, the
sort cognitive science aims to sort out and solve.
All these questions force themselves on us once
we take Descartes’ vision of the universe seriously.
Descartes is not unaware of them. His basic strategy
for dealing with them consists in the radical split
that he makes between mind and body. Bodies, he
holds, are parts of the mechanical universe; minds
are not. Physics can deal with the body, but not
with the mind. We know that we are not merely
automata because (1) we can use language, and (2)
we are flexible and adaptable in a way no machine
could be; reason, Descartes says, “is a universal instrument which can be used in all kinds of situations.” It is quite possible, he says, that we could
construct a machine that utters words—even one
that utters words corresponding to movements of
its body. But it is not possible, he thinks, for a machine to “give an appropriately meaningful answer
to whatever is said in its presence, as the dullest of
men can do” (DM 6.56–57, p. 120).*
But merely dividing mind from body does not
completely solve the problem. The question arises,
How are they related?
The Mind and the Body
Descartes concludes that the mind and the body are
distinct substances, so independent of each other
that either could exist without the other. They are,
*This, of course, is precisely the aim of research on
artificial intelligence. Will it be successful? Descartes bets
knowledge of external things seems to belong to
the mind alone, not the composite of mind and
body” (p. 396).
A New Vision of Reality
Descartes’ metaphysics completes the worldview
that was emerging already in the work of Copernicus, Kepler, and Galileo. Our world is a giant
mechanism, not unlike a clock (see Descartes’ analogy on p. 396). It was created by God, but now it
runs on the principles of mechanics, and our science is mechanistic in principle. The entire material universe, including the human body, is just a
complex machine. The world has become a secular
world. What happens can be explained and predicted without reference to any purposes or intentions of the creator. We are, we might say, worlds
away from the intrinsically purposive, inherently
value-laden, God-directed world of the medievals.
Dante now begins to look like a fairy tale or, at
best, a moral allegory with no literal truth value at
all. It is, perhaps, no great surprise that the Meditations ends up on the index of forbidden books.
There are, to be sure, human minds or souls,
and they are not caught up in the mechanism of the
material world. They are, in fact, radically free.
Even God does not have more freedom than a soul
(see Meditation IV). But as we’ll see, this disparity
between soul and body is not so much the solution
to a problem as it is a problem in itself.
Great as Descartes’ achievement is, he bequeaths to
his successors a legacy of unsolved problems. There
are those who refuse to accept his radical beginning
point and remain true to a more traditional approach, usually Aristotelian. But his methodological
doubt has been powerfully persuasive to many, and
the continued progress of physics seems to be evidence that his basic view of the world is correct. For
the next 150 years, Cartesianism, together with its
variants, will be the dominating philosophy on the
European continent. As we’ll see, different assumptions are at work in Britain, but even here the Cartesian spirit of independence is pervasive. Still, there
are nagging worries. Let us note three of them.
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and one of Descartes’ lasting legacies is a philosophical puzzle about how it is possible. But it is
safe to say that a philosophy that does not solve the
mind–body problem cannot be considered entirely
God and the Problem of Skepticism
As we have seen, Descartes takes skepticism very
seriously. He pushes skeptical arguments about as
far as they can be pushed, and he thinks that in the
cogito he has found the key to overcoming skepticism. But even if we grant that each of us knows,
by virtue of the cogito, that we exist, knowledge
of the world depends on the fact that God is not a
deceiver. And that depends on the proofs for the
existence of God.
What if those proofs are faulty? Then I am back
again in solipsism, without a guarantee that anything
exists beyond myself. Are the proofs—or at least
one of them—satisfactory? Descartes is quite clear
that everything depends on that question; “the certainty and truth of all my knowledge derives from
one thing: my thought of the true God” (p. 390).
He is sure that the proofs are as secure as the theorems of geometry. But is he right about that?
The Preeminence of
In earlier philosophies there are many problems—
the one and the many, the nature of reality, explaining change, the soul, the existence of God—and
the problem of knowledge is just one among the
rest. Descartes’ radical skepticism changes that.
After Descartes and until very recent times, most
philosophers have regarded epistemological problems as foundational. Among these problems of
knowledge, the problem about knowing the external world is the sharpest and most dangerous.
Can we know anything at all beyond the contents
of our minds? Unless this skeptical question can be
satisfactorily answered, nothing else can be done.
Epistemology is, for better or worse, the heart of
philosophy for the next several hundred years.
These are problems that Descartes’ successors wrestle with, as we’ll see. Next, however,
we want to look at a figure who is often neglected
moreover, of a radically different character. Still,
he says, mind and body are so intimately related as
to form “a single unified thing” (p. 397). But how
can you be two things and yet one single thing?
Descartes gives no explanation.
“What is matter?—Never mind.
What is mind?—No matter.”
Furthermore, the mind must be able to affect
the body. When you decide to eat an ice cream
cone, your body obeys its commands. But as
some of Descartes’ contemporaries pointed out to
him, it is at best unclear how this is possible on
his view, since he posits an immaterial mind that
is completely distinct from the mechanistic world
of extended things. The diplomat and philosopher
Princess Elisabeth of Bohemia puts the problem
pointedly in a letter to Descartes. She cannot comprehend, she writes,
the idea through which we must judge how the soul
(nonextended and immaterial) can move the body;
nor why [we should sooner believe] that a body can
be pushed by some immaterial thing, than the demonstration of a contrary truth (which [Descartes]
promises in [his] physics) should confirm us in the
opinion of its impossibility. . . . I nevertheless have
never been able to conceive of such an immaterial
thing as anything other than a negation of matter
which cannot have any communication with it.7
Not only has Descartes failed to explain this obvious
phenomenon, Elisabeth suggests, but also his views
seem to imply that the phenomenon is impossible.
The problem runs the other way, too. For just
as the mind can move the body, so events affecting the body can affect the mind, as when you stub
your toe or light reflects from this book into your
eye, leading you to perceive the words on the page.
How can an alteration in the shape or position of
certain material particles cause us to feel pain or
think of Cleveland? Descartes seems to have no
clear answer to these questions.
The view that the mind and body have a two-way
causal interaction is known as interactionism,
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ex nihilo nihil fit
material things
1. Quoted in S. V. Keeling, Descartes (London: Oxford
University Press, 1968).
2. Quotations from René Descartes’ Discourse on the
Method of Rightly Conducting One’s Reason and Seeking
the Truth in the Sciences, in The Philosophical Writings
of Descartes, ed. John Cottingham, Robert Stoothoff,
and Dugald Murdoch (Cambridge: Cambridge
University Press, 1985), are cited in the text
using the abbreviation DM. References are to part
numbers and page numbers in the classic French
edition, followed by page numbers in this edition.
3. Quotations from René Descartes, The Principles of
Philosophy, in The Philosophical Works of Descartes,
vol. 1, ed. Elisabeth S. Haldane and G. R. T. Ross
(n.p.: Dover, 1955), are cited in the text using
the abbreviation PP. References are to the classic
French edition, followed by the page numbers in
this edition.
4. Quoted by Martin Heidegger in The Way Back into
the Ground of Metaphysics, reprinted in Existentialism
from Dostoevsky to Sartre, ed. Walter Kaufmann
(New York: Merchant Books, 1957).
5. Trans. Ronald Rubin, Meditations on First Philosophy
(Claremont, CA: Areté Press, 1986).
6. Keeling, Descartes, 252.
7. Trans. Lisa Shapiro, The Correspondence between
Princess Elisabeth of Bohemia and René Descartes
(Chicago: University of Chicago Press, 2007), 68.
in the history of modern philosophy: Thomas
Hobbes. Hobbes is more interesting to us than to
previous generations, perhaps, because he presents
an alternative response to the new science. Some
recent thought about the mind—that associated
with artificial intelligence—can be regarded as a
struggle to replace the paradigm of Descartes with
that of Hobbes.
Descartes argues that there is no way you could
tell that your ideas about the external world were
correct unless there were a nondeceptive God to
guarantee their basic rightness. Can you think of
any way you might be able to know there is a world
corresponding to your ideas? Try to construct a
view that provides this reassurance without depending on God.
rules of method
clear and distinct
first philosophy
evil demon
representational theory
thinking thing
innate ideas
light of nature
subjective reality
formal reality
eminent reality
mel70610_ch18_404-437.indd 404 07/09/18 04:33 PM
Materialism and the Beginnings of Empiricism
Descartes offered a dramatic new beginning
in philosophy. Besides sweeping away old
rubbish and legitimating the new science,
Descartes’ work seemed a breath of fresh air in its
clarity and apparent simplicity. But—there were
those nagging problems. If mind and body are as
distinct as Descartes claims, how do they communicate? Does the will really escape the causal
net? Do we really have all those innate ideas? Are
Descartes’ proofs for God’s existence really proofs?
And if not, can we escape skepticism about the external world?
Across the English Channel, British thinkers
read Descartes with interest, but they were not entirely convinced. In this chapter, we look at three
of these philosophers, examining their response
to the challenges of Cartesian thought: Thomas
Hobbes, who refuses to exclude human beings
from the new scientific principles; John Locke,
who is determined to trace all our ideas to their
source in experience; and George Berkeley, who
tries to apply empiricist principles more consistently than Locke does. A consideration of these
three will prepare us for that most radical of empiricists in the next chapter: David Hume.
Thomas Hobbes: Catching Persons
in the Net of the New Science
For various reasons, Descartes stops short of supposing that his geometrical mechanics can account
for everything. The most obvious exceptions are
mental activities: thinking, imagining, doubting,
feeling, and willing. Because Descartes believes it
is beyond question that each of us is first and foremost a thinking thing—and as free in our decisions
as God himself—there can be no Cartesian physics
of human beings. As thinkers, we escape the web of
mechanical causality.*
*For Descartes’ reasons, see his argument for the
distinctness of mind and body in Meditation VI. He is also
convinced that our minds, being rational, are infinitely adaptable. This, he thinks, distinguishes us from any conceivable
automaton, no matter how cleverly designed. See p. 401.
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But are Descartes’ reasons for thinking so
really conclusive? What would happen if we tried
to understand human beings as systems of matter
in motion, completely enclosed in the natural
world described by mechanical physics? Thomas
Hobbes (1588–1679) makes the experiment. We
will not survey the whole of Hobbes’ philosophy,
but it will prove useful to bring into our sense of
the great conversation what he has to say about
human beings—our place in the world and our life
together. So we focus our attention on his views
about mind and morals.
Hobbes accepts without reservation the new
physics of the nonhuman world. Let us review
some of the salient features of this new science
and contrast them with the older, Aristotelian
• Whereas for Aristotle and his medieval disciples,
motion is development toward some fulfilling
goal (a change from potentiality to actuality),
for the new science, motion is simply a body’s
change of place in a neutral geometrical space.
• Galileo substitutes the distinction between
accelerated motion and constant motion for the
Aristotelian distinction between motion and
rest. For Galileo, rest is simply a limiting case
of motion. In no sense is rest the culmination or
fulfillment or goal of a motion.
• Motion is the normal state of things; it does not
require explanation, as in the medieval view.
Only changes in motion (in direction or rate)
need to be explained, and they are explained in
terms of other motions.
• Therefore, there is no natural center to the
universe where things “rest.” Since something
in motion continues in a straight line to infinity
unless interfered with, the universe is conceived
to be infinite rather than finite, and there are no
privileged places in it.
• Scientific explanation can no longer mention the final causes of things—those essences
toward which development has been thought
to strive. In the geometrical world of Galileo
and Descartes, all explanation is in terms of
contact, of some prior impetus or push. It is as if
the rich Aristotelian world with its four causes
is stripped down to only the “efficient cause.”
Purposiveness is eliminated from the physical
In his comments on the Meditations, Hobbes
claims to be unconvinced by Descartes’ arguments
concerning the independence of the mind from the
body. For all Descartes has said, Hobbes thinks,
the thing that thinks may just as well be a physical body! Indeed, Hobbes is convinced that “the
subject of all activities can be conceived only after
a corporeal fashion.”1
If so, then the mind cannot
be thought of as a thing independent of the body.
It becomes just one of the ways that bodies of a
certain sort function.† Can this claim be plausible?
Hobbes is as convinced as Descartes that method is
the key to progress. He calls his method—which he
claims to have learned from Galileo and his friend
William Harvey (who discovered the circulation
of the blood)—the method of resolution and
composition. The first stage, resolution, consists
in the analysis of complex wholes into simple elements. It resembles Descartes’ second rule.‡ In
the second stage, the elements are reassembled, or
composed again into a whole. This is analogous to
Descartes’ third rule. When we have both resolved
and composed the complex whole we began with,
we understand it better than we did before we applied the method. Both Galileo and Harvey offer
impressive examples of successes attained by this
*Compare Hobbes in this respect to the Greek atomists
(“The World,” in Chapter 2). You might also like to remind
yourself of Plato’s critique of this kind of nonpurposive explanation, pp. 160–161.
†Hobbes, like nearly all the moderns, is a great opponent
of Aristotle. And yet this conclusion is basically Aristotelian.
(See p. 206.) Likewise, his account of how we gain knowledge
about the world is Aristotelian in spirit, if not in detail. In
more than one way, Hobbes must be counted a “critical Aristotelian.” Descartes, by contrast, clearly stands in the Plato–
Augustine tradition. The principal difference between Hobbes
and Aristotle is the former’s repudiation of final causes, of
potentiality, and of the essences that make them work. This
difference transforms everything it touches.
‡See p. 362.
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method. Galileo uses it to understand and predict
the trajectory of cannonballs and other projectiles.
Harvey uses it to understand and explain the circulation of blood in the human body.
We will see Hobbes trying to use these methods
to understand both mind and society. His aim is to
analyze human beings into their simplest elements—
which he takes to be bits of matter in motion—and
then understand a community of persons in terms of
the way these elements interact. Hobbes aspires to
be the Galileo or the Harvey of the human world.
He is convinced that a scientific understanding of
human nature will be both a contribution to knowledge and a practical benefit. If we could but organize
society on the basis of truths about ourselves, rather
than on the basis of ignorance and superstition, we
could avoid conflict and live together in peace.
Minds and Motives
Life, says Hobbes,
is but a motion of limbs, the beginning whereof is
in some principle part within; why may we not say,
that all automata (engines that move themselves by
springs and wheels as doth a watch) have an artificial
life? For what is the heart, but a spring; and the
nerves, but so many strings, and the joints, but so
many wheels, giving motion to the whole body,
such as was intended by the artificer? (L, 129)2
The distinction, in other words, between living
and nonliving things is not to be found in a soul, or
a life principle, or in anything nonmaterial. Living
things are just those things that move because they
have a source of motion within them. They are not
in principle different from automata or robots that
we ourselves might make. In fact, we could say
that robots are alive, too; their life is artificially created, but it is life nonetheless. The internal motions
causing the movements of automata are, in principle, no different from the heart, nerves, and joints
of the human body. Living things, whether natural
or artificial, are just matter in motion.
In a way, Descartes does not yet disagree. For
he thinks that animals are just “machines”; and animals are undoubtedly alive. But what about the life
of the mind? What of thought and feeling? What of
desire, imagination, and memory? Can these too
be plausibly considered just matter in motion? We
have seen Descartes’ negative answer. Can Hobbes
make a positive answer plausible?
Let us begin with thinking. What are thoughts?
They are everyone a representation or appearance, of
some quality or other accident of a body without us,
which is commonly called an object. (L, 131)
Note that Hobbes expresses no doubt that there
are indeed bodies—objects—independent of ourselves. He seems simply not to take the Cartesian
reasons for doubting seriously.* Descartes, notoriously, thinks there is a serious problem here—that
all our experience might be just as it is while nothing at all corresponds to it in the world beyond our
minds. That there are bodies, Descartes holds, is
something that needs to be proved. Hobbes offers
no proofs. It is as though he thinks it beyond question. Of course our thoughts represent bodies. Of
course bodies really exist. To be sure, we are sometimes mistaken about them, but these mistakes give
us no reason to withhold belief in external things
altogether. In fact, if it were not for those objects,
we would not have any thoughts at all!
The original of them all is that which we call sense,
for there is no conception in a man’s mind which
hath not first, totally or by parts, been begotten
upon the organs of sense. The rest are derived from
that original. (L, 131)
The source of all our thoughts is to be found in
sensation.† And sensation is an effect in us of the
action of those external bodies on our eyes, ears,
nose, skin, and tongue. Motions are communicated
to our sense organs from these bodies; these motions set up other motions in the sense organs; and
these motions are in turn propagated by the nerves
“inwards to the brain and heart.” We take the
*Here again Hobbes stands to Descartes as Aristotle to
Plato. See p. 183.
†For all Hobbes’ tirades against Aristotle, this is a very
Aristotelian view. It is the dead opposite of Descartes’ belief
in innate ideas (see p. 382). It means that he can have no
tolerance for Descartes’ first proof for the existence of God.
Compare Thomas Aquinas’ rejection of the ontological argument of Saint Anselm on essentially similar Aristotelian
grounds (see p. 319).
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us that are pressed, are they anything else but divers
motions; for motion produceth nothing but motion.
But their appearance to us is fancy. (L, 131)
It will pay us to consider this passage carefully,
for it contains a crucial ambiguity. On the one hand,
Hobbes says that sensations are themselves nothing but motion; “for motion produceth nothing but
motion.” If we take that seriously, then Hobbes is
what we call a materialist. The entire life of the
mind is nothing more than matter in motion. For
sensations are motions, and all the rest is built up
out of sensations. There are no distinctive mental
disturbance inside us to be a representation of the
object from which the motions originated. Here,
then, are the origins of our experiences of colors,
sounds, tastes, smells, hardness and softness, and
so on. These experiences we call sensations, or, to
use Hobbes’ seventeenth-century term, “fancy.”
But what of these experiences themselves? Can
the smell of a rose really be “resolved” into motions? Here is what Hobbes says. In the objects that
cause them, these qualities are
but so many several motions of the matter, by
which it presseth our organs diversely. Neither in
While women were generally excluded from
formal education in early modern Europe,
some educated themselves and published their
own works of philosophy. Some, such as Anne
Conway and Mary Astell, published their works
anonymously. The poet, playwright, and scientist
Margaret Cavendish (1623–1673) was one of the
few who published under her own name, producing
philosophical treatises, a book of philosophical letters, and a philosophically significant science fiction
novel. She personally knew Descartes, Hobbes, and
other intellectual luminaries of her time.
Cavendish shares Hobbes’ commitment to
materialism, writing,
Nature is material, or corporeal, and so are
all her Creatures, and whatsoever is not material is no part of Nature, neither doth it belong any ways to Nature.3
But, setting herself against Hobbes and the dominant Western tradition as a whole, she offers a
novel way to navigate between Cartesian dualism
and the Hobbesian view of the world as a purely
mechanistic assemblage of atoms. She argues that
all material things are composed of three types
of matter—inanimate, sensitive, and rational—
blended together in every particle of the natural
world. Inanimate matter cannot move itself, but
is moved by self-moving sensitive matter; sensitive matter, in turn, takes direction from rational
matter. Such a view is superior to Descartes’, she
thinks, because his dualistic view cannot explain
how immaterial mind moves material bodies. It is
superior to Hobbes’, she thinks, because it avoids
the unsavory and, to many, implausible implication
that mind is nothing more than a particularly complicated mechanism composed of lifeless atoms.
On this basis, Cavendish also develops alternative theories of causation and perception. Bodies do
not cause other bodies to move by imparting motion
to them. Rather, self-moving matter perceives the
motions of bodies around it and at least usually
responds to those motions in particular ways. For
instance, when you throw a ball, the animate matter
in the ball perceives the motion of your hand and
responds by moving itself in the direction that your
hand is traveling. Perception works similarly: as the
ball flies through the air, the sensitive matter in the
air perceives its motion and communicates a pattern
to the sensitive matter in your eyes, which moves
itself to form a sensory impression of the ball.
Cavendish’s philosophical work was mostly
ignored in the seventeenth century, but she anticipates positions and arguments developed by other
early modern philosophers and discusses issues relevant to twentieth- and twenty-first-century philosophy of mind. Her unusual brand of materialism
demonstrates that Hobbes’ mechanistic view of the
world was not the only way to respond to the rise
of the new science.
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to Descartes, for whom mind is a radically different
kind of substance from body. Descartes, then, is a
metaphysical dualist, and Hobbes is a monist. For
Hobbes, there is only one kind of finite substance.
Sensations, the “original” of thought, are motions. But this poses a problem. Paraphrasing Galileo’s laws of inertia, Hobbes admits that “when a
body is once in motion, it moveth, unless something else hinder it, eternally” (L, 133). Why is it,
then, that sensations do not remain with us? The
answer is that in a way they do—but in a diminished way only. For new sensations are ever pouring in on us; and by these succeeding motions the
previous ones are weakened. This “decaying sense,”
as Hobbes calls it (L, 133), is imagination and
When an image (the decayed motion left by
a sensation) is combined with a sign, he says, we
have understanding. And this is common to
both humans and the higher animals. For instance,
a dog who comes when his master whistles gives
evidence that he understands what is wanted of
him. The whistle is a sign connected in this case
to tendencies to act. Hobbes, unlike Descartes, is
quite content to speak of a dog as thinking this or
that. The difference between the dog and ourselves
is not absolute (that we have a soul, which the dog
completely lacks) but is a matter of degree.
Because all thinking originates in sensation,
we cannot think of something we have not experienced. We can combine sense elements in novel
ways to produce purely imaginative thoughts of
unicorns or centaurs. But things that are neither
sensed nor invented on the basis of sensations are
inconceivable. This has an important consequence:
We can have, Hobbes says, no positive thought of
God. “Whatsoever we imagine,” he says, “is finite.
Therefore there is no idea or conception of anything we call infinite” (L, 140). We do, of course,
have words for God; we can call him a “being of
infinite perfection”—as Descartes does. But these
terms do not really function to describe God;
rather, says Hobbes, they are signs of our intention
to honor him.
Hobbes groups our thoughts into two classes:
unregulated (as when we daydream) and regulated
thoughts. The first kind may seem to follow each
qualities at all. Mind is just matter that is moved in
distinctive ways.
On the other hand, Hobbes says of these motions that “their appearance to us is fancy.” Now if
it is not the motions themselves that constitute the
sensations, but their appearance to us, then the sensations must be distinct from the motions. Under
this interpretation Hobbes is not a materialist at
all; he is what we call an epiphenomenalist. An
epiphenomenalist thinks there are unique mental
qualities, that they are causally dependent on physical states, but that they do not in turn affect the
physical world. They more or less ride piggyback
on the physical, but they have no physical effects.
Is Hobbes a materialist or an epiphenomenalist about the mind? It is probably impossible to
decide. He talks both ways, perhaps because he is
simply unaware of the distinction. His intentions,
however, are fairly clear. He wants to be a materialist, to resolve everything—including all aspects
of mental life—into matter in motion. Let us consider him, therefore, to be a materialist about the
mind. In this way, he stands in dramatic opposition
“The light of human minds is perspicuous words . . .;
reason is the pace, increase of science, the way and the
benefit of mankind, the end.”
–Thomas Hobbes
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find ourselves “entangled” in them like the bird in
the lime twigs.* In an often quoted phrase, Hobbes
tells us that
words are wise men’s counters, they do but reckon
by them; but they are the money of fools, that value
them by the authority of an Aristotle, a Cicero, or a
Thomas. (L, 143)
Only a “fool” thinks that we can buy truth with
the words of some authority. A “wise man” realizes that they are only signs that, if properly used
to “reckon” with, may possibly yield us a science.
“When ideas fail, words come in very handy.”
Johann Wolfgang von Goethe (1749–1832)
We use words to reason, to think rationally
about some matter. What is reasoning? Hobbes
has a view of reasoning that some artificial intelligence researchers these days look back to as
prophetic. Reasoning, he tells us, is “nothing but
reckoning, that is adding and subtracting, of the consequences of general names agreed upon for the marking and signifying of our thoughts” (L, 133–134).
As the cognitive scientist nowadays says, reasoning
is computation.
Whether we reason about the theoretical
consequences of some geometrical axiom, about
means to attain a certain end, or about the practical
consequences of some course of action, these regulated thoughts are governed by desire. We wouldn’t
bother if we didn’t want to find out the answer.
So the motivation behind all our rational thinking
is passion. Hobbes must now ask, Can these desires and wants, these likes and dislikes, themselves
be accounted for in terms of the metaphysics of
*Compare to the Confucian doctrine of the rectification
of names (p. 225).
†What is at stake here is whether purpose and intention can be given a mechanistic explanation. We have seen
that Plato and, following him, Aristotle, think not. For this
reason, Aristotle believes we need to ask about final causes in
addition to the other three kinds. This question is still hotly
other in a wholly random way, but on careful observation, Hobbes tells us, we can see that their
order mirrors a prior order of sense experiences.
The appearance of randomness comes from the variety of our experiences. If at one time we see Mary
with John and then again with Peter, the thought of
Mary may be accompanied by either that of John
or that of Peter. But it will be associated in some
way dependent on earlier experiences. In trying to
find a pattern to unregulated thoughts, Hobbes is
making a suggestion that will be developed into the
doctrine of the association of ideas.*
More interesting, however, are regulated
thoughts. These do not even have an appearance
of randomness but exhibit a definite order. One
thing Hobbes has in mind is the kind of thinking that
looks for means to attain some goal, as when a student considers which classes take to complete her
degree. Another kind of regulated thought consists
in inquiry about the consequences of taking a certain
action, as when a student considers what her life will
be like if she changes her curriculum from history to
engineering. In regulated thought about the world,
we are always searching for either causes or effects.
Such a hunt for causes is usually carried out
in words, which are useful both as aids to memory
and as signs representing our thoughts to others.
Hobbes recognizes the benefits we derive from
having such objective signs of our inner thoughts,
but he also warns us about the errors into which
they can easily trap us.
Seeing then the truth consisteth in the right ordering of names in our affirmations, a man that seeketh
precise truth had need to remember what every
name he uses stands for, and to place it accordingly,
or else he will find himself entangled in words, as a
bird in lime twigs, the more he struggles the more
belimed. (L, 142)
The cure for these evils of confusion is to be
found in definition, to which Hobbes attributes the
success of geometry, “the only science that it hath
pleased God hitherto to bestow on mankind” (L,
142). Words need to be carefully defined, lest we
*See the use to which David Hume puts this notion,
Chapter 19.
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The idea that in a “commonwealth,” or state,
good and evil are not relative to individuals is one
we will explore shortly. But in what Hobbes calls
a “state of nature,” where there is no government, good and evil strictly depend on the individual. If an individual desires X, she judges X to be
good; if he dislikes Y, he considers Y evil. And from
those judgments there is (in the state of nature) no
This analysis is an important step in Hobbes’
materialistic program. Goodness is not a Platonic
Form or an unanalyzable property that some things
have. Everything is just body and motion. But some
(living) bodies are related in certain ways to other
bodies in such a way that the former bodies utter
the words “That is good” about those latter bodies.
They do so when the latter produce motions in the
former that are pleasurable.
What is pleasure? Pleasure, Hobbes tells us,
is just “a corroboration of vital motion, and a help
thereunto,” while pains are a “hindering and troubling [of] the motion vital” (L, 150). Feeling good,
in other words, is just having all our normal bodily
processes working smoothly; the more active and
untroubled they are, the better we feel—and what
we all want is to feel good.
“Pleasure is Nature’s test, her sign of approval.”
Oscar Wilde (1854–1900)
It seems, then, that regulated thoughts are regulated by desire, that desire is always for the good,
and that “good” is our name for whatever produces
pleasure. The end point of a train of regulated
thoughts is some action on our part—an action we
think will gain us some good. These actions, when
caused by thoughtful desires in this way, are called
At this point, Hobbes meets a natural objection. It is not, someone might claim, desire that
causes voluntary action; it is will. And willpower
*Compare the doctrine of Protagoras, the Sophist, who
said, “Of all things, the measure is man” (p. 62).
We have seen that living things are distinguished from nonliving things by having the origins of some of their motions within them. Hobbes
must now give a more careful account of this. He
distinguishes two sorts of motions peculiar to animals: vital and voluntary motions. Vital motions
are such things as the circulation of the blood, the
pumping of the heart, breathing, and digestion.
Voluntary motions, by contrast, are those for
which the cause is to be found in some imagination. John imagines how pleasant it would be to go
with Jane to the movies; he walks out of his way
in the hope that their paths will cross. It is clear
that if imagination itself is nothing but the diminished motions of sense, voluntary motions such as
walking in a certain direction have their origin in
internal motions.
These small, perhaps infinitesimally small beginnings of motion Hobbes calls endeavor. Endeavor can either be toward something (in which
case it is called desire) or away from something
(which is called aversion). In desire and aversion
we find the sources of all human action.
Desire and aversion allow Hobbes to introduce
certain value notions. What we desire, he says, we
call good; what we wish to avoid we call evil.
And these value distinctions are invariably founded
on pleasure and pain, respectively: What gives us
pleasure we call good; what causes pain we call
evil.* It is important to realize that good and evil
are not thought to attach absolutely to things. They
are not properties that things have independent of
our relation to them. The words “good” and “evil,”
Hobbes tells us,
are ever used with relation to the person that useth
them; there being nothing simply and absolutely so;
nor any common rule of good and evil to be taken
from the nature of the objects themselves; but from
the person of the man, where there is no commonwealth; or, in a commonwealth, from the person
that representeth it; or from an arbitrator or judge,
whom men disagreeing shall by consent set up, and
make his sentence the rule thereof. (L, 150)
*It is clear that Hobbes is a hedonist. See Epicurus,
p. 236.
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continual prospering, is that men call felicity; I mean
the felicity of this life. For there is no such thing as
perpetual tranquility of mind, while we live here;
because life itself is but motion, and can never be
without desire, nor without fear, no more than
without sense. (L, 155)
In this life there can be no resting, no “tranquility.” No sooner has one desire been fulfilled than
another takes its place. The reason Hobbes gives
for this is that life itself is nothing but motion. So
there is a perpetual striving for the satisfaction of
desires; when this is successful over some period
of time, we say that during that period a person is
All of us desire this felicity, Hobbes says. But it
is easy to see that if we are not to be mere pawns
of fortune, we must also control access to it; that
is, we must be guaranteed the power to satisfy whatever desires we may happen to have.
I put for a general inclination of all mankind, a
perpetual and restless desire of power after power,
that ceaseth only in death. And the cause of this, is
not always that a man hopes for a more intensive
delight, than he has already attained to; or that he
cannot be content with a moderate power: but because he cannot assure the power and means to live
well, which he hath present, without the acquisition
of more. (L, 158–159)
This kind of power is, of course, a relative
matter. In a world of limited resources, if I gain
more power to guarantee the satisfaction of my desires, I often diminish your power to satisfy your
desires. In seeking to assure my own felicity,
I threaten yours. So we are naturally competitors.
I seek my good. You seek yours. And we each seek
to increase our own power to ensure that we at
least do not lose those goods we now have.†
can override our desires. I desperately want another slice of that dark, rich chocolate cake, but I
exercise my will and say, “Thank you, but no.” Can
Hobbes deal with this common experience?
He does so by asking what we mean by “will.”
It cannot be anything else, he thinks, than “the last
appetite in deliberating” (L, 154). Will, then, is a
desire. I do desire that slice of cake, but I also have
desires that run counter to that desire: I want not to
look piggish; I want not to gain too much weight.
On this occasion, these latter desires outweigh the
former; they dictate my action, and so they are
what we call my will. Will is nothing but effective
desire. Since we have already seen that Hobbes believes desire and aversion can be given an analysis
in terms of matter in motion, there is no need (as
Descartes thinks) to bring in nonmaterial factors to
explain the origin of voluntary actions.*
Our voluntary actions, then, are governed in the
last analysis by passion—by our desires and aversions,
our loves and hates. And since the good we seek and
the evil we try to avoid are rooted in our own pleasures and pains, action is always egoistic. It is my own
good that I seek, if Hobbes is right—not yours. As
Hobbes puts it, “of the voluntary acts of every man,
the object is some good to himself” (L, 165).
Moreover, we seek such good continually. It
is not enough to act once for our own pleasure;
the next moment demands other acts that have the
same end. Happiness—or felicity, as Hobbes calls
it—is just a life filled with the satisfaction of our
Continual success in obtaining those things which
a man from time to time desireth, that is to say,
*It is clear that Hobbes is a determinist—that is, one
who thinks that for every event, including all human actions,
there is a set of sufficient conditions guaranteeing its occurrence. All actions are caused; and the causes of these causes
themselves have causes. This poses a problem, of course:
the problem of freedom of the will. We saw that Descartes,
who is not a materialist, can hold that our decisions escape
this universal determinism that holds for the material world;
even God, Descartes says, is not more free than we are.
Hobbes cannot think so. He has a solution to this problem,
but because the same solution is more elegantly set out by
Hume, we consider it in the next chapter. If you want a preview, see “Rescuing Human Freedom” in Chapter 19.
*Contrast this notion of happiness to the rather different
hedonistic doctrine of the Epicureans (pp. 236–240).
†If this seems unrealistic to you as a model of relations
among individuals, consider political and economic rivalries
among nations. As we will see, Hobbes has an explanation of
how we have gotten beyond this competitive situation on the
individual level. It is instructive to compare this picture of
restless competitiveness to Augustine’s two cities,
pp. 286–287.
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the earth; no navigation, nor use of the commodities that may be imported by sea; no commodious
building; no instruments of moving and removing,
such things as require much force; no knowledge of
the face of the earth; no account of time; no arts;
no letters; no society; and which is worst of all,
continual fear, and danger of violent death; and the
life of man, solitary, poor, nasty, brutish, and short.
(L, 161)
Solitary, poor, nasty, brutish—and short! Such is our
life in a state of nature.*
Let us remind ourselves of what Hobbes
claims to be doing here. He is trying to use the
same method on human nature and society that
*Compare to Xunzi’s views about the result of our natural
desires, untamed by social rules. See pp. 230–231.
Although there are natural differences in our
power, we are equal enough in natural gifts that
each of us has reason to fear the other. As Hobbes
says, even “the weakest has strength enough to kill
the strongest” (L, 159), whether by force, stealth,
or collusion with others. Because of this equality,
the egoistic desire for happiness—plus the need to
be assured of it by a continual increase of power—
leads human beings to be enemies. So our natural
condition (i.e., before any artificial arrangements
or agreements among us) is one of war of “every
man against every man.” Even when we are not actually fighting one another, the threat of conflict
always looms over us. In such a condition, Hobbes
there is no place for industry, because the fruit
thereof is uncertain; and consequently no culture of
Although Francis Bacon (1561–1626) was both
a jurist and a statesman (rising as high as lord
high chancellor in the England of James I), he was
most passionately interested in reforming intellectual life and creating a new kind of science. His
principal philosophical works are The Advancement of
Learning (1605) and Novum Organum (1620).
Bacon believed that old habits had to change;
it was a bad mistake to look to the authorities of
the past because nearly everything about the natural world remained to be discovered. Traditional
philosophers, he said, are like spiders, spinning
out intricate conceptions from their own insides.
Alchemists and other early investigators were like
ants, scurrying about collecting facts without any
organized method. We should rather follow the
example of the bees; let scientists cooperate in
acquiring data, offering interpretations, conducting
experiments, and drawing judicious conclusions.
Bacon identified four “idols” that, he said, have
hindered the advance of knowledge: (1) idols of the
tribe—tendencies resident in human nature itself,
such as imagining that the senses give us a direct
picture of their objects or imagining there is more
order in experience than we actually find; (2) idols
of the den—people’s inclination to interpret experiences according to their private dispositions or
favorite theories; (3) idols of the marketplace—
language that subverts communication through
ambiguities in words or in names that are assumed
to name something but actually do not; and (4) idols
of the theater—the dogmas of traditional philosophy, which portray the universe no more accurately
than stage plays portray everyday life.
How can we counter these tendencies to revere
the past and idolize the wrong things? Bacon recommended a method of careful experimentation and
induction. Supporting a theory by simple enumeration of positive instances, however, is not good
enough. We must look particularly, he said, for
negative instances—especially if the theory is one
we are fond of—and for variations in the degrees of
presence and absence of factors so that we can find
correlations between them.
Nature, Bacon told us, can be commanded
only by obeying her; by submitting to nature’s own
ways through carefully designed experiments, we
can gain knowledge. Knowledge, he said, is power.
And the result of a reformed science will be mastery
of nature, leading to a higher quality of human life.
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The Natural Foundation of
Moral Rules
Hobbes has “resolved” human society into its elements. Let us see how he thinks it can be “composed” back again into a whole. If Hobbes succeeds
in this stage, we will have an explanation of the
human world, including its ethical and political
aspect, in purely mechanistic terms.
In the state of nature, human beings are governed by their egoistic passions, their endeavor to
ensure their own happiness. This leads to the “war
of everyone against everyone,” a deadly competition for the power to guarantee for each person
what he considers good. How can this “state of
nature” be overcome? Partly, Hobbes says, by passion itself and partly by reason.
One of the strongest passions is the fear of death.
It is this fear, together with the desire for happiness, that motivates us to find a way to end the state
of nature. We must remember that in the state of
nature there are no rights and wrongs, no goods and
bads, except where an individual thinks there are.
We each take as much as we have power to take
and keep. An individual’s liberty extends as far as his
power. But if a person in this state of nature realizes
how unsatisfactory this condition is, he will see that
it is a precept, or general rule of reason, that every
man ought to endeavor peace, as far as he has hope
of obtaining it; and when he cannot obtain it, that
he may seek and use all helps and advantages of war.
The first branch of which rule containeth the first
and fundamental law of nature; which is, to seek
peace and follow it. The second, the sum of the
right of nature; which is, by all means we can, to
defend ourselves. (L, 163)
Hobbes speaks here of a right of nature and of a
law of nature. What can he mean? In a universe
composed merely of matter in motion, how can
there be rights and laws in nature? Hasn’t Hobbes
already denied that there is any right or wrong in
this condition?
If we interpret Hobbes sympathetically, it seems
that a law of nature must simply be an expression of
the way things go. Jones, who by nature seeks his own
happiness and fears death, is worried about his
future. This is just how it is. In reasoning about his
Galileo and Harvey use on the nonhuman world.
He resolves human beings into their component
elements—the motions characteristic of living
things—and finds this competitive and restless
striving to be the result.
This analysis is supported, he believes, by observation. Hobbes lived during extremely troubled
times in England.* There was a long struggle between
king and Parliament over the right to make laws and
to collect taxes. This struggle reflected a broader
quarrel between the old nobility and the established
Church of England on the one hand and the rising
middle classes and religious dissenters of a more radical Protestant sort on the other. Those on each side,
in Hobbes’ view, were trying to preserve against the
other side the means of their own happiness.
The outcome was a protracted and bloody civil
war, the execution of King Charles I, a period of
government without a king under the protectorate
of Oliver Cromwell, and finally the Restoration of
the monarchy under Charles II (to whom Hobbes
had been a tutor in mathematics). The “state of
nature” into which Hobbes resolves human society
was very nearly the actual state of affairs in England
during a good part of Hobbes’ life. Hobbes did not
conjure the war of all against all from nowhere; he
saw it—or something like it—with his own eyes.
Still, Hobbes does not intend his account of the
state of nature to describe society at all times and
places. Nor is it supposed to describe society at
some time in the distant past. It is intended to picture the results of an analytical decomposition of
human society into its elements. Left to their own
devices, the theory says, individuals will always act
egoistically for their own good, and the inevitable
consequence is a state of war—each of us fearing
our neighbor and striving to extend our sphere of
control at our neighbor’s expense. This is the result
of the resolution phase of Hobbes’ method.
We now need to look at the composition phase,
where the elements are put back together again.
And here we focus primarily on Hobbes’ view of
the ethical consequences.
*For the English Civil War, see “English Civil
War,” Wikipedia,
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others as we are willing to allow with respect to
ourselves. There should be—to end the state of
war—a mutual limiting of rights, as far as this is of
mutual benefit to each. (Note that Hobbes does not
suppose that anyone would do this altruistically or
out of sheer goodwill. The motivation throughout
is hedonistic and egoistic.)
This agreement to limit one’s claims has the
flavor of a contract. And, indeed, Hobbes’ view
is one version of a social contract theory,* but
you can see that there is a difficulty at this point.
Suppose Jones and Smith, in a state of nature, each
agree to limit their own liberty to the extent that
the other does as well. What reason does each one
have to trust the other to keep his promise? Is there
anything to keep Smith from violating the contract
if he thinks it is in his interest to do so and calculates that he can get away with it? It seems not.
Hence, in a state of nature, contracts and promises
are useless. They are just words! This is a serious
problem. It looks as if you cannot get here from
there—that is, to a moral community from a state
of nature. Can Hobbes solve this problem?
What is necessary to make the contract operative, Hobbes says, is “a common power set
over them both, with right and force sufficient to
compel performance” (L, 167). Only when punishment threatens can Jones trust Smith to keep her
promise. For only then will it clearly be in Smith’s
self-interest not to break it. There is, then, a necessity for
some coercive power, to compel men equally to
the performance of their covenants . . . and such
power there is none before the erection of a commonwealth. (L, 168)
*The idea of a contract or agreement as the basis for
society is taken up by a number of other political thinkers:
Spinoza, Rousseau, and—most important for the founding of
the American Republic—John Locke (see the following section). They differ about the powers such a contract bestows
on a government, about whether such a contract could or
could not be revoked, and about the grounds on which a citizen might withdraw allegiance. Nonetheless, social contract
theories generally stress both the rights of individuals and the
necessity of consent as the basis of legitimate government.
Thus, they are both a reflection of and an influence on the
individualism of the times.
situation, Jones sees that replacing war with peace
would relieve his fear of death; and if he didn’t have
to be so afraid of his neighbors, he could more satisfactorily fill his own life with “felicity.” The rule
to “seek peace” is a rule that an egoistic but rational
creature such as Jones will inevitably—naturally—
come upon. He will reason that if he is going to
have any chance of a good life, he has to get beyond
this state of war. A law of nature for Hobbes
is simply a rule of prudence that results from the
shrewd calculation of a scared human being.
A right of nature must have a similar foundation. In the state of nature there are no “rights” in
the usual sense. If, in a state of nature, someone
injures me, I cannot complain that my “rights” have
been infringed. But precisely because there are no
rules, I am at liberty to use whatever means I can
muster to preserve my life and happiness. Hobbes
uses the term “right” to refer to this liberty everyone has in the state of nature. So Jones having
the “right” to defend himself is simply the fact that
there are no rules that curtail his tendency to preserve his life and happiness. If, however, Jones (and
everyone else) exercises this liberty without limit,
the results will be a war of all against all.
This suggests to the rational person that some
of the liberty we have in the state of nature must be
given up. To give it up entirely, however, would
make no sense at all; if Jones gave up the liberty of
defending himself altogether, he would become the
prey of everyone—and an egoistic agent could not
rationally allow that. So this “right” of self-defense
remains something that Jones will always retain.
We have, then, one right and one law, which
Hobbes uses as the foundation for a series of deductions. Once we have these, others “follow”
in almost geometrical fashion. For instance, the
second law, Hobbes tells us, is
that a man be willing, when others are so too, as far
forth as peace and defense of himself he shall think
it necessary, to lay down this right to all things; and
be contented with so much liberty against other
men, as he would allow other men against himself.
(L, 163–164)
Each of us, according to this second law, should
be content with as much liberty with respect to
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You might think that this is a rather extreme position, but remember that Hobbes’ analysis of human
beings leads to a rather extreme view of the problem: the war of all against all. For extreme situations,
extreme solutions may be required. In any case, we
have here an example of a worldview built on the
foundations of the new science, a view that includes
human beings, together with their mental and moral
life. Let us summarize a few of the main points:
• Sensation, thought, motivation, and voluntary
action are all analyzed in terms of matter in
• All events, including human actions, are subject
to the same laws of motion that Galileo has
• Only egoistic desires are recognized as motivators, so all actions are performed for the welfare of the agent.
• If you peel off the veneer of civilization, you are
left with individuals in conflict.
• This conflict can be resolved on the basis of the
very passions that produce it, provided people
reason well about their individual long-term
• Morality and law are simply the best means
available, the only means to stave off imminent
death and the possible loss of felicity. Being
moral and law-abiding is no more than a smart
strategy for self-preservation.
• Unless these rules are enforced by a powerful
ruler, everything will collapse again into the
state of nature.
It is a stark vision that Hobbes gives us. He
thinks that acceptance of modern science forces
that view upon us. Is that correct, or are there less
forbidding alternatives?
1. Contrast the world-picture we get from the
Galileo–Descartes–Hobbes gang with that of
Aristotle and his medieval followers with respect to
• a description of the universe;
• what needs explaining;
• kinds of explanation desired; and
• the place of values in the world.
2. How does Hobbes try to explain thinking? Compare
his views, if you can, with recent work in artificial
This is the rationale for that “great Leviathan,”
that “artificial man,” that “mortal god,” the state.
It is the state, together with the power of enforcement that we agree to give it, that gets us beyond
the state of nature. Only in such a community can
moral and legal rules exist and structure our lives.
The great danger in any community, Hobbes
believes, is that it might fall back again into the state
of nature, where everyone thinks he or she has the
right to be judge of everything. So a state cannot
allow individuals to follow their own consciences,
to decide for themselves what is good and evil. The
sovereign established by the contract, whether
king or governing assembly, must be absolute; its
word must be law. The sovereign declares what is
good, what is evil—and even what those terms shall
mean. Lacking this absolute power in the sovereign,
we stare chaos and civil war in the face again.
In setting up a government for the purpose of
escaping the dangers of the state of nature, then,
we are bound to treat its actions as our own. So
once a sovereign power is established, there can
be no right of rebellion against it, for it cannot be
right to rebel against ourselves. Nor can any subject claim that the sovereign power has acted unjustly, no matter what it does, for whatever it does
is done by the citizens themselves who established
it. Moreover, because the sovereign is not a party
to the contract, but is established by it, it follows
that the sovereign cannot violate the contract.
A government may do bad things, Hobbes allows,
but it can never be accused of injustice.
Because the aim of government is to secure a
condition of peace among the citizens, it must have
all the powers that are necessary to this end. And
because individual actions are governed by opinions, the sovereign must have the power to determine which opinions and doctrines may be taught
in the state. Finally, the sovereign power must be
one and undivided. Hobbes thought one lesson
of the civil war was that power divided between
king and Parliament made conflict inevitable. So a
unified sovereign must have the power to make the
law, to judge cases according to the law, and to
administer the application of law. Otherwise, the
whole point of establishing a government by limiting individual natural rights would be lost.
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certainly a subject, even for its nobleness, worth
our labour to inquire into. . . .
If by this inquiry into the nature of the understanding, I can discover the powers thereof; how far they
reach; to what things they are in any degree proportionate; and where they fail us, I suppose it may be
of use to prevail with the busy mind of man to be
more cautious in meddling with things exceeding
its comprehension; to stop when it is at the utmost
extent of its tether; and to sit down in a quiet ignorance of those things which, upon examination,
are found to be beyond the reach of our capacities.
(Essay, Intro, 1, 3; vol. 1, pp. 25–28)4
You can see that Locke intends to recommend a
certain modesty with respect to our capacity for
knowledge. Moreover, he thinks that circumscribing the scope of our understanding will be
a very useful thing to do; he is not writing just to
satisfy curiosity on this score, but to mitigate the
quarrels—religious, political, or what have you—
leading even to wars, that arise when men believe
they have certainty about things that are actually
beyond our powers to know.
3. How are good and evil explained by Hobbes?
Compare with the view of Augustine (e.g.,
pp. 270–274.).
4. How do Hobbes and Descartes differ on the nature
of the will? Relate this to the metaphysics of each
5. Describe what Hobbes calls “the state of nature,”
and explain why it has the character it does have.
6. How does Hobbes think we can have gotten, or can
get, beyond the state of nature?
7. What makes Hobbes think that a “social contract”
will require the “coercive power” of a state?
John Locke: Looking to Experience
Although a clear implication of Cartesian method is
that “first” philosophy is really epistemology, Descartes’ own meditations are still in the metaphysical
mode. Hobbes, too, is primarily a metaphysician—
the metaphysician of matter in motion, in contrast
to Descartes’ dualism. The credit (or blame) for
taking seriously the idea that theory-of-knowledge
issues must come first in philosophical thought
belongs to the English philosopher John Locke
(1632–1704). With Locke the lesson is drawn:
Unless we are clear about our capacities for gaining
knowledge, we are likely to waste our time in controversies over matters that are beyond our grasp
and end in confusion. Understanding how our kind
of mind works and whence its contents come has to
be the first order of business. So he writes, over a
period of years, the famous Essay Concerning Human
Understanding. This long and complex treatise, in
four books, is usually thought to mark the proper
beginning of empiricism in philosophy.* Locke
begins the Essay with these words:
Since it is the understanding that sets man above the
rest of sensible beings, and gives him all the advantage and dominion which he has over them; it is
*There are, of course, forerunners of the empirical
trend. Francis Bacon is a distinguished empiricist (see the
Sketch on p. 412) and Hobbes also, to some extent. There is
an immense amount of detail in Locke’s long and rambling
Essay, much of it having only historical interest. We will
focus our attention on those parts that have made a lasting
impact on the great conversation.
“It is ambition enough to be employed as an underlabourer in clearing the ground a little, and removing
some of the rubbish which lies in the way to knowledge.”
–John Locke
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ideas: —How comes it to be furnished? Whence
comes it by that vast store which the busy and
boundless fancy of man has painted on it with an
almost endless variety? Whence has it all the materials of reason and knowledge? To this I answer,
in one word, from EXPERIENCE. In that all our
knowledge is founded; and from that it ultimately
derives itself. (Essay, II, I, 2; vol. 1, pp. 121–122)
There are two sources of such experience.
On the one hand, there is the experience of external objects via our senses; this is the first and
greatest source of ideas. Locke calls this source
sensation. Here we get the ideas of yellow, hot,
cold, hard, soft, bitter, sweet, and so on. On the
other hand, we can reflect internally on how our
minds work, garnering ideas of mental operations.
Locke calls this source reflection. From reflection
we get the ideas of perceiving, thinking, doubting,
believing, reasoning, knowing, willing, and so on.
These two sources supply the raw materials for all
our knowledge.
The understanding seems to me not to have the
least glimmering of any ideas which it doth not
receive from one of these two. External objects
furnish the mind with the ideas of sensible qualities,
which are all those different perceptions they produce
in us; and the mind furnishes the understanding with
ideas of its own operations. (Essay, II, I, 5; vol. 1,
p. 124)
It is worth noting that Locke takes for granted,
as Hobbes also does but Descartes does not, that
there are “external objects” supplying us with ideas
of themselves.* This supposition sits uneasily with
other parts of Locke’s view, and Berkeley (later in
this chapter) and Hume (Chapter 19) exploit this
Ideas can be classified as either simple or complex. A simple idea is one that, “being in itself
uncompounded, contains in it nothing but one uniform appearance, or conception in the mind” (Essay, II,
II, 1; vol. 1, p. 145). What might seem to be a
How shall he proceed? He states his purpose
more precisely in these words:
to inquire into the original, certainty, and extent of
human knowledge. (Essay, Intro, 2; vol. 1, p. 26)
He says that he will use a “historical, plain method”
in this investigation. By this, he means that he will
try to trace our ideas to their origin, using no more
esoteric technique than directing our attention to
what should be obvious to any careful inquirer. So
we find him again and again asking us to look and
see whether we agree with what he finds.
He notes in the introduction that he will use the
word “idea” in a very broad sense: for “whatsoever is the object of the understanding when a man
thinks” (Essay, Intro, 8; vol. 1, p. 32). He means
to include everything from sensations of red and
warm, through the contents of memory and imagination, to abstract ideas of a circle or an animal species, and even to our idea of God. That there are
such ideas in our minds, Locke says, we all admit.
The first question is this: How do they get there?
Origin of Ideas
Book I of the Essay is devoted to destroying one
possible answer: that ideas, any or all of them, are
innate. Locke’s argument is that if there are innate
ideas, they must be universally held in all minds.
Perhaps the most plausible cases are trivialities such
as “Whatever is, is.” But Locke argues that (1) not
even such ideas are universal (e.g., they are not
present in the minds of children or idiots), and (2)
universality would prove innateness only if there
were no other way such ideas could be acquired.*
Locke is convinced that there is another way, and
to that he turns in Book II, the longest and most
influential book of the Essay.
If the mind is not innately supplied with ideas,
where do they come from?
Let us then suppose the mind to be, as we say,
white paper, void of all characters, without any
*Locke is attacking a very crude version of innate ideas;
it is not clear that it applies to Descartes’ version of innateness as an idea that a thinking being would possess even if
nothing else but that being existed. See p. 382.
*Locke does offer some arguments on behalf of this assumption much later in the Essay (see Book IV, Chapter XI),
but they seem to be no stronger than the arguments Descartes destroys in Meditation I.
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but only as modifications of a substance. Locke
strives to show that our ideas of space, time, and
infinity are modes, built by adding simple ideas to
simple ideas.
Relations are of many kinds and are very important in our knowledge. Examples are knowing that
one thing occurs before another, that this is next to
that, that a causes b, that x is identical with y, and
that two numbers added make a third number. But
because Locke’s discussion of the general nature of
relations is both complex and confused, we pass it
by—though we will examine what he says about
certain relations, such as are involved in our idea
of personal identity and in our knowledge of things
external to us.
Of more lasting significance is what Locke has
to say about substances. The notion of substance, as
we have seen, plays a significant role in philosophical thought from the time of Aristotle onward. In
that tradition, a substance is a composite of form
(making it the kind of thing it is) and matter (which
makes it the particular instance of that kind of
thing). Substances have properties, some of which
are essential to its nature—the properties that
make it what it is—and some are incidental. But in
trying to trace our idea of substance back to simple
ideas, Locke finds nothing, either in sensation or
in reflection, that answers to this Aristotelian
notion of substance. Instead, he says, we find only
the properties of the substance—its color, for instance, or its shape and hardness. We simply posit
the existence of the substance as the substratum
in which those properties inhere, as the thing that
has these properties. And we name particular substances, such as gold, for the distinctive collection
of properties it has: yellowness, hardness, malleability, and so on.
Not all of those properties, Locke says, are of
the same kind.
For, to speak truly, yellowness is not actually in
gold, but is a power in gold to produce that idea
in us by our eyes, when placed in a due light: and
the heat, which we cannot leave out of our ideas
of the sun, is no more really in the sun, than the
white colour it introduces into wax. These are both
equally powers in the sun, operating, by the motion
and figure of its sensible parts, so on a man, as to
single experience may be composed of several
simple ideas; touching a piece of ice, for instance,
produces not one idea but the two distinguishable
ideas of cold and hard. Simple ideas are the elements
of all our thinking.
When the understanding is once stored with these
simple ideas, it has the power to repeat, compare,
and unite them, even to an almost infinite variety,
and so can make at pleasure new complex ideas. But
it is not in the power of the most exalted wit, or
enlarged understanding, by any quickness or variety
of thought, to invent or frame one new simple idea
in the mind, not taken in by the ways before mentioned. (Essay, II, II, 2; vol. 1, p. 145)
“Nothing ever becomes real till it is
John Keats (1795–1821)
Even with respect to simple ideas, however, the
mind carries on certain operations. For instance,
(1) we can distinguish one clearly from another;
(2) we can compare them, noting their likenesses
and differences; (3) we can put them together in various ways; (4) we can name them; and most important, (5) we can frame abstract ideas. How do we
do that? Locke gives this example. Seeing the same
color today, in chalk or snow, which we yesterday observed in milk, we consider that appearance
alone (disregarding the crumbly nature, the coldness, or the liquidity it is associated with) and give
it the name whiteness. We abstract the color from
the other qualities by paying selective attention to
it, neglecting its surroundings. That is the way,
Locke says, “universals, whether ideas or terms,
are made” (Essay, II, XI, 9; vol. 1, p. 207). It is
this power to abstract that distinguishes us from the
other animals. All of these powers are known to us
by reflection on the operations of our own minds.
We come now to complex ideas, which can
be classified under three heads, Locke tells us:
modes, relations, and substances. There is a long
and complicated chapter on our ideas of modes
(what the medievals called “accidents” or “incidental properties”). These do not exist on their own,
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So Locke comes to agree with Descartes—and to
disagree with Hobbes—in believing that there are
minds and bodies and that they are radically different kinds of things.
In sum, although we have clear ideas of some
of the primary qualities of both bodies and souls
(for instance, solidity on the one hand and thinking
on the other), the substance of each is unknown to
us—and is bound to remain so.
For whensoever we would proceed beyond these
simple ideas we have from sensation and reflection,
and dive further into the nature of things, we fall
presently into darkness and obscurity, perplexedness and difficulties, and can discover nothing further but our own blindness and ignorance. (Essay,
II, XXIII, 32; vol. 1, p. 418)
Idea of Personal Identity
Still, Locke holds that there are such immaterial
substances as souls. But if we know substances,
including souls, through their properties, can we
count a thing as the same thing if its properties
change? This question becomes more pressing
when we apply it to our selves. I, in my maturity,
possess very different qualities from those I had at
ten years old. What is it that makes me the same
person throughout? Is this the rule: same person,
same soul? That had been the traditional answer,
at least in the West, but Locke gives a different
answer, which has had great influence.
Locke argues that it turns out to be completely
irrelevant whether the soul substance present in
me at age ten is the same soul substance I now
have. In keeping with his determination to trace all
our ideas to experience, Locke asks, What is it that
gives me the idea of myself at all? and he answers,
For, since consciousness always accompanies thinking, and it is that which makes every one to be what
he calls self, . . . as far as this consciousness can be
extended backwards to any past action or thought,
so far reaches the identity of that person. (Essay, II,
XXVII, 11; vol. 1, p. 449)
If I were not conscious of myself, I would be
no more a self than a stone is. Then if I ask what
makes the self I now am identical with the self I was
make him have the idea of heat; and so on wax, as
to make it capable to produce in a man the idea of
white. (Essay, II, XXIII, 10; vol. 1, pp. 400–401)
From this, we see that Locke accepts that division of qualities into primary and secondary that we
first met in Galileo.* The properties that are actually
in gold are its extension, shape, motion, and impenetrability. These are gold’s primary qualities,
the qualities it really has.
Properly speaking, however, gold is not yellow;
that color is not one of its primary qualities, does
not belong to it as it is—apart from us. Gold does
have a secondary quality: the power to produce
yellow sensations in creatures such as ourselves.
The idea is that the primary qualities of gold, when
joined with the primary qualities of light, of the
eye, and of the nervous system of a human being,
bring about (somehow) an experience of color. But
we would be mistaken to read that sensation back
into the substance itself.
Idea of the Soul
Substances, then, can be known to exist as the causes
of the ideas they produce in us. But this means,
Locke holds, that we have just as good an idea of
spiritual substance as of material. Just as we frame
the idea of a material substance from the ideas of
sensation, so from ideas of reflection,
we are able to frame the complex idea of an immaterial
spirit. And thus . . . we have as clear a perception
and notion of immaterial substances as we have of
material. . . . The one is as clear and distinct an
idea as the other. . . . For whilst I know, by seeing
or hearing &c., that there is some corporeal being
without me, the object of that sensation, I do more
certainly know, that there is some spiritual being
within me that sees and hears. (Essay, II, XXIII, 15;
vol. 1, pp. 406–407)
What applies in the one case applies in the
other, however. In neither case do we have any
knowledge of what such a substance is in itself. We
know only that there must be such a substance to
serve as the substratum for physical properties in
the one case and mental properties in the other.
*See pp. 357–358.
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We own up to our present actions as ours because we are conscious of doing them. We own
up to having done past actions on exactly the same
grounds. Locke thinks it is “probable” that one and
the same consciousness is always attached to the
same soul, but personal identity has a psychological
rather than a metaphysical basis.*
Language and Essence
Book III of the Essay has to do with words.† It is in
words, by and large, that we express our knowledge, so an examination of the “origins, extent, and
certainty” of our knowledge ought to clarify how
language works. According to Locke, words are
necessary for “sociable” creatures such as ourselves,
language being “the great instrument and common
tie of society” (Essay, III, I, 1; vol. 2, p. 3). Their
principal function is to stand as signs for ideas.
The comfort and advantage of society not being to
be had without communication of thoughts, it was
necessary that man should find out some external
sensible signs, whereof those invisible ideas, which
his thoughts are made up of, might be made known
to others. . . . The use, then, of words, is to be sensible marks of ideas; and the ideas they stand for are
their proper and immediate signification. (Essay, III,
II, 1; vol. 2, pp. 8–9)
Words, then, “in their primary or immediate
signification, stand for nothing but the ideas in the
mind of him that uses them” (Essay, III, II, 2; vol. 2,
p. 9). And the aim of speaking is to make hearers
understand these ideas by awakening similar ideas
in them. The connection between a word and the
idea it stands for is arbitrary. The word “black” no
more resembles my idea of black than the word
*In recent decades the concept of personal identity has
been given extended consideration, often in terms of science
fiction examples. The work of Bernard Williams, Derek
Parfit, and Peter Unger makes clear the philosophers’ debt to
Locke. You might look at the delightful little book by John
Perry, A Dialogue on Immortality and Personal Identity (Indianapolis, IN: Hackett, 1978).
†Here is another way in which Locke is a forerunner
of things to come; much twentieth-century philosophy
was preoccupied with linguistic matters. See, for instance,
Chapter 26, on the thought of Ludwig Wittgenstein.
yesterday, the answer has to be in conformity with
this. I must be conscious of that self—remember
having the experiences of yesterday’s self.
Personal identity, then, cannot consist in
sameness of substance. For all we know, it might
be that a succession of soul substances could constitute a self, provided each were connected to the
last by memories of what was thought and done in
it.* To take the contrary view, if a single substance
were “wholly stripped of all consciousness of its
past existence . . . beyond the power of ever retrieving it again,” that would constitute the end of
one person and the beginning of another (Essay, II,
XXVII, 14; vol. 1, p. 455).
In the movie All of Me, Lily Tomlin wakes up
in the body of Steve Martin. In fact, she shares that
body with him. What is it that accounts for Tomlin
still being Tomlin, for her continued identity—
even in a new body? Is it that her substantial soul
has moved over? Locke says we could not know
that, and it is irrelevant in any case. What makes
her remain herself is the memory of her past life
and the continuity of her interests, passions, and
goals—in short, her consciousness.
Locke gives us this example. Consider your
little finger and suppose that it gets cut off.
Upon separation of this little finger, should this consciousness go along with the little finger, and leave
the rest of the body, it is evident the little finger
would be the person, the same person; and self
would then have nothing to do with the rest of the
body. (Essay, II, XXVII, 17; vol. 1, p. 459)
Locke remarks that “person” is a forensic term,
the sort of term that appears in courts of law. It
has to do with what we can be held responsible for,
praised and blamed for, rewarded and punished for.
If Locke is right about personal identity, my person
extends itself beyond present existence to what is
past, only by consciousness,—whereby it becomes
concerned and accountable; owns and imputes to
itself past actions, just upon the same ground and
for the same reason as it does the present. (Essay, II,
XXVII, 26; vol. 1, p. 467)
*Compare this line of thought to the Buddhist doctrine
of anātman (pp. 41–45).
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of a raven is as particular a thing as any individual
raven. The way it differs is this: I use it to represent this raven and that raven—and indeed all the
ravens there are or could be.
It is true that nature produces things that are
similar to each other: ravens, for example. And it is
even true, Locke admits, that a particular raven has
a real essence, meaning by that those elements
that are the ultimate foundation of the qualities
we are aware of through our senses. But such real
essences of things are completely unknown to us.
Whatever it is in a given substance that causes our
simple ideas of black, feathered, and winged is forever beyond our ken.
Moreover, though the things we call ravens are
undeniably similar to each other, there is nothing
that all ravens have that forces this similarity: no
form or essence that determines the existence or
coexistence of those qualities. Locke cites natural
variations in individuals as evidence of this. Nature
produces “monsters” of various kinds, deformed
individuals without what we normally take to be
properties essential to a kind. If we just pay attention to our experience, it seems clear that any
property of a thing, no matter how “essential” we
deem it, may, in a given instance, be lacking. How
could that happen if nature were arranged in species where each particular instance of the species
were determined to be the kind of thing it is by a
universal form?
We do, of course, have abstract ideas and
words, and they do present essences to us. But
these are what Locke calls nominal essences. As
the word suggests, nominal essences are attached
to names. Nominal essences, while not entirely arbitrary, are our own creations; they are not read off
directly from nature itself. We do not consider the
ultimate constitution of things in forming our ideas
of essences because we cannot. Nor do we consider
substantial forms, since those are mere inventions
of the philosophers. What we do consider are the
sensible qualities of things—those clusters of qualities that seem to hang together with some regularity
and get a name.
And if this be so, it is plain that our distinct species are
nothing but distinct complex ideas, with distinct names
annexed to them. It is true every substance that exists
“schwarz” does. But if hearing one of these words
brings an idea into my mind that is similar to the
idea in the speaker’s mind, the word has done its
job. Locke takes pains to deny that words stand
directly for things in the world. It is not entirely
wrong to think this, he says, but precisely put, words
represent such things only indirectly, by representing ideas, which in turn stand for these things.
Again we pass by much of the detail in Locke’s
discussion. Let us look, though, at what Locke has
to say about words for essences. As we have seen,
knowledge in the Aristotelian tradition is knowledge of substance and principally of the form of a
substance that is its essence. Such knowledge tells
us what it is to be a thing of a certain kind. Essences
determine kinds of things: horses, clouds, tides,
memories, thefts, and so on.
Now our ideas for kinds of things are, as Locke
has told us, formed by abstraction, and we understand how that works. We consider a theft, say, and
ignore everything that makes it this particular theft;
we are then left with the general idea of theft. And
general words represent general ideas. Most of our
words—proper names aside—are general in this
sense and represent abstract ideas.
But where in the world do we find essences or
It is plain, by what has been said, that general and
universal belong not to the real existence of things;
but are the inventions and creatures of the understanding, made by it for its own use, and concern
only signs, whether words or ideas. Words are general . . . when used for signs of general ideas, and
so are applicable indifferently to many particular
things; and ideas are general when they are set up as
the representatives of many particular things. (Essay,
III, III, 11; vol. 2, pp. 21–22)
This is a conclusion of considerable importance. If Locke is right, the whole tradition stemming from Plato and Aristotle has been mistaken
in thinking of universality as a feature of reality—
whether in the Platonic heaven of Forms or in
Aristotelian real essences embedded in things. Everything is particular. Universality is to be found
only in the way certain particular things (mental
ideas and words) function. Ideas and words are universal in their use, but not in their nature. My idea
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Since the mind, in all its thoughts and reasonings,
hath no other immediate object but its own ideas,
which it alone does or can contemplate, it is evident
that our knowledge is only conversant about them.
Knowledge then seems to me to be nothing but
the perception of the connexion of and agreement, or disagreement and repugnancy of any of our ideas. In this
alone it consists. (Essay, IV, I, 1; vol. 2, p. 167)
We can have knowledge no further than we
have ideas. (Essay, IV, III, 1; vol. 2, p. 190)*
This might not seem to be a very promising beginning. Surely, you want to say, we want to know
more than how our ideas are related to each other.
We want to know about reality, the world—what
there actually is! In fact, Locke himself states such
an objection, but he thinks he can meet it. Let us
see how.
First we should note that he accepts that view
of knowledge common in the tradition from Plato
to Descartes—when we know, we have certainty.
“The highest probability amounts not to certainty,
without which there can be no true knowledge,”
Locke says (Essay, IV, III, 14; vol. 2, p. 203). This,
of course, sets the standard very high.† The higher
you set the standard, the fewer propositions will
pass muster, so we mustn’t be surprised when
Locke again and again laments the small extent of
our knowledge.
By the agreement and disagreement of ideas, he
means the way ideas are put together in propositions. There are many distinct ways this happens,
but let us focus on only one, that concerning real
existence. He has said that we can have no knowledge beyond our ideas, but here, apparently
without realizing it, he strikes a new note. He explains this kind of knowledge as “of actual real existence agreeing to any idea” (Essay, IV, I, 7; vol. 2,
p. 171). Now the existence of something that
“agrees to” one of our ideas cannot just be a matter
of the relations among ideas. Yet it is only with this
*See again the remark about “disaster” by John Searle,
footnote, p. 373.
†For a critique of this demand for certainty,
see C. S. Peirce, p. 597. See also Ludwig Wittgenstein,
pp. 645–649.
has its peculiar constitution, whereon depend those
sensible qualities and powers we observe in it; but
the ranking of things into species (which is nothing
but sorting them under several titles) is done by us
according to the ideas that we have of them: which,
though sufficient to distinguish them by names, . . .
yet if we suppose it to be done by their real internal
constitutions, . . . by real essences, . . . we shall be
liable to great mistakes. (Essay, III, VI, 13; vol. 2,
p. 69)
Nominal essences, then, are not “copied from
precise boundaries set by nature,” but are “made
by man with some liberty” (Essay, III, VI, 27; vol.
2, p. 77). They may be more or less carefully constructed, given our experience of things. And,
no doubt, they can be improved by more careful
observation. But they are one and all creatures of
their creator, not a simple mirror of reality.
This, then, in short, is the case: Nature makes many
particular things, which do agree one with another
in many sensible qualities, and probably too in their
internal frame and constitution: but it is not this
real essence that distinguishes them into species; it
is men who, taking occasion from the qualities they
find united in them . . . range them into sorts, in
order to their naming, for the convenience of comprehensive signs. (Essay, III, VI, 36; vol. 2, p. 86)
It is, then, Locke says, “evident that men make
sorts of things” (Essay, III, VI, 35; vol. 2, p. 85).
Nature produces particular beings in great abundance; many of them resemble each other. But “it
is nevertheless true, that the boundaries of the species, whereby men sort them, are made by men”
(Essay, III, VI, 37; vol. 2, p. 87). That science of the
real essences of things that Aristotle and his followers dreamed of is not possible.
The Extent of Knowledge
Locke told us in the beginning of the Essay that his
purpose was to determine the origins, the certainty,
and the extent of our knowledge. His method has
been to examine our understanding, getting clear
about the materials it has to work with and how
it operates with them. Now, in the fourth book of
the Essay, he is at last ready to address the questions
about knowledge directly. It begins this way:
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meditation? (3) Locke has told us that knowledge
requires certainty, but now he says that though
it is not as certain as intuition or demonstration,
the assurance of the senses amounts to knowledge
anyway. We will see other philosophers exploring
these problems.*
It is clear that Locke has accepted the main
themes in the representational theory of perception
and knowledge.† The mind is a storehouse of ideas.
These ideas are the immediate or direct objects of
our knowledge. We suppose them to be representations or signs of things beyond themselves. They
are such, we think, by virtue of their being produced in the mind by the causal powers of those
external things. So we can know “real existence”
indirectly, by virtue of the “correspondence” of our
ideas with those really existing items in the world
beyond the mind. This is a pattern of thought that
ever totters on the brink of skepticism—How
do you check the correspondence?—and we see
Locke struggling against drawing the skeptical conclusion.‡ He piles reason on inconclusive reason
for resisting the plunge, but it is not clear that anything will rescue him.
1. What is Locke’s aim in the Essay Concerning Human
2. What are Locke’s arguments against innate ideas?
3. What are the two sources of our ideas?
4. How do we get abstract ideas?
5. How do we come to have the idea of substance?
6. What can we know of substance?
7. What is the idea of a soul? How does it arise?
8. What is, and what is not, the origin of our idea of
personal identity?
9. Contrast real essences with nominal essences.
Why is it important to Locke to make this
10. How do we know real things existing outside our
*See especially Berkeley and David Hume, pp. 431 and
†Review the discussion of these themes in the chapter on
Descartes, pp. 372–373.
‡Compare the view of Aquinas, who does not make
ideas the objects of our mental acts, p. 330.
sort of agreement that Locke can meet that natural
objection to his principles that we noted previously.
What then can we know to “really” exist? Like
Descartes, Avicenna, and Augustine before him,
Locke believes we have a clear intuitive knowledge
of our own existence. This “we perceive . . . so
plainly and so certainly, that it neither needs nor is
capable of any proof. For nothing can be more evident to us than our own existence” (Essay, IV, IX,
3; vol. 2, pp. 304–305). We can know demonstratively that God exists. Locke rejects Descartes’ first
proof of God, which depends on an innate idea of
God in us, but he offers an argument based on our
own existence and the ex nihilo nihil fit principle:
From nothing, you get nothing.
The knowledge of other things we have by sensation. Other than ourselves and God, we can know
of the existence of any other thing
only when, by actual operating upon [us], it makes
itself perceived by [us]. For the having the idea of
anything in our mind, no more proves the existence
of that thing, than the picture of a man evidences his
being in the world, or the visions of a dream make
thereby a true history.
It is therefore the actual receiving of ideas from
without that gives us notice of the existence of other
things, and makes us know, that something doth
exist at that time without us, which causes that idea
in us. . . . And of this, the greatest assurance I can
possibly have . . . is the testimony of my eyes, . . .
whose testimony . . . I can no more doubt, whilst
I write this, that I see white and black, and that
something really exists that causes that sensation in
me, than that I write or move my hand. . . .
The notice we have by our senses of the existing
of things without us, though it be not altogether so
certain as our intuitive knowledge, or the deductions of our reason employed about the clear abstract ideas of our own minds; yet it is an assurance
that deserves the name of knowledge. (Essay, IV, XI,
1–3; vol. 2, pp. 325–327)
Several questions press themselves on us:
(1) If our knowledge does not reach further than
our ideas, as Locke insists, how do we know these
ideas are being received from something outside
ourselves? (2) Isn’t his confidence in the testimony
of the senses simply naive, given Descartes’ first
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as much as he can to preserve the rest of mankind.
(Gov’t, II, II, 6; pp. 119–120)
Locke realizes, of course, that not everyone will
conform to this natural law, even though it is present in their reason. So, like law under government,
it needs to be enforced. But who will do it where
there is no government? The answer is—everyone.
And that all men may be restrained from invading
others’ rights, and from doing hurt to one another,
and the law of Nature be observed, which willeth the
peace and preservation of all mankind, the execution
of the law of Nature is in that state put into every
man’s hands, whereby every one has a right to punish
the transgressors of that law to such a degree as may
hinder its violation. (Gov’t, II, II, 6; p. 120)
Violations of the natural law, together with this
universal right to punish violations of it, produce
the “inconveniences” men hope a government will
save them from. For in the state of nature, there is
no avoiding the situation where men will be judges
in their own cause; and we know that in such cases,
self-love will make men partial to themselves and their
friends; and, on the other side, ill-nature, passion, and
revenge will carry them too far in punishing others,
and hence nothing but confusion and disorder will
follow. (Gov’t, II, II, 13; p. 123)
It is to restrain the “partiality and violence of men”
that God instituted government, Locke says.
“No man is good enough to govern another
man without that other’s consent.”
Abraham Lincoln (1809–1865)
Obviously, however, there is a problem here.
For absolute rulers are men, too. What is there in
absolute sovereignty to restrain their partiality and
violence? So Hobbes’ solution won’t work; it won’t
solve the problem of partiality and violence but, at
best, will locate it at one very powerful point in a
community. What would work? Because men are
by nature all free, equal, and independent, no one
can be put out of this estate and subjected to the
political power of another without his own consent,
Of Representative Government
Locke’s influence extends far beyond his epistemology. In fact, he may be best known in America for
his political thought, which had a decisive impact on
Thomas Jefferson and the other founders of the United
States. Though trained as a physician, Locke was near
the centers of power in late seventeenth-century
England, serving in several official posts himself
and being a close friend and associate of Lord Shaftesbury, who rose to be Lord Chancellor. Because
of the intrigues of the time, he left England on
several occasions for his safety and lived for some
years in France and in Holland. He lived through
the “Glorious Revolution” of 1688, which brought
William and Mary to the English throne and established the rights of an independent Parliament. So
he had reason to be interested in political matters.
Like Hobbes, Locke begins his theory of government with speculations about a state of nature.
But unlike Hobbes, he doesn’t end up justifying an
absolute sovereign. Locke follows Thomas Aquinas
in thinking that even before government is instituted,
human beings, through their reason, have access to
the natural law.* So he does not see men in a state
of nature as mere calculating desire machines, the way
Hobbes does. In a natural state, humans have a
sense for justice and injustice, right and wrong, independent of any law declared by a sovereign. And
this makes a difference.
Locke does not discuss the contents of this
natural law to any great extent. It seems to be more
or less coextensive with the Golden Rule: Do unto
others as you would have them do unto you.
The state of Nature has a law of Nature to govern
it, which obliges every one, and reason, which is
that law, teaches all mankind who will but consult
it, that being all equal and independent, no one
ought to harm another in his life, health, liberty,
or possessions; for men being all the workmanship
of one omnipotent and infinitely wise Maker; . . .
they are made to last during His, not one another’s
pleasure. . . . Every one as he is bound to preserve
himself, . . . so by the like reason, when his own
preservation comes not in competition, ought he
*See the fuller discussion of natural law in the chapter on
Aquinas, pp. 332–333.
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Locke imagines that in a state of nature the
fruit on the trees, the water in the streams, and
the animals in the forest are common to all. What
could make part of that mine rather than yours?
Locke gives some examples. If you fill a bucket
with water from the common source and take it to
your dwelling, and if someone else then takes that
water rather than fetch some for himself or herself, that person has injured you and have done you
an injustice. Why? Because you have mixed your
labor with this water; and your labor belongs to
you. Anyone can fish in the ocean and bring back
a catch, but the catch then belongs to the one who
fishes, and whoever takes it away without permission does wrong.
He that is nourished by the acorns he picked up
under an oak, or the apples he gathered from the
trees in the wood, has certainly appropriated them
to himself. Nobody can deny but the nourishment is
his. I ask, then, when did they begin to be his? when
he digested? or when he ate? or when he boiled? or
when he brought them home? or when he picked
them up? And it is plain, if the first gathering made
them not his, nothing else could. That labour put a
distinction between them and common. That added
something to them more than Nature, the common
mother of all, had done, and so they became his
private right. (Gov’t, II, V, 27; p. 130)
Private property, then, antedates the institution of
government; it is not created by positive law, but
secured by it.*
What sort of government is it, then, that can
best protect life, health, liberty, and possessions?
To avoid the dangers of anarchy at the one extreme
and tyranny at the other, it must be a government
of limited powers. And to ensure that it resists the
temptation to make itself an exception to the laws
it passes for others, it must be responsible to the
people who established it. So Locke envisions a representative government with two powers: the legislative, to enact laws for the good of the whole, and
which is done by agreeing with other men, to join
and unite into a community for their comfortable,
safe, and peaceable living, one amongst another, in
a secure enjoyment of their properties. . . . When
any number of men have so consented to make one
community or government, they are thereby presently incorporated, and make one body politic,
wherein the majority have a right to act and conclude the rest. (Gov’t, II, VIII, 95; pp. 164–165)
“Man’s capacity for justice makes democracy
possible, but man’s inclination to injustice
makes democracy necessary.”
Reinhold Niebuhr (1892–1971)
Like Hobbes, Locke envisages a “contract” as
the basis for government. But Locke’s contract is
not made between the people with a sovereign; it
is a contract people make with each other. Each
agrees to give up the right to punish violations of
the natural law, provided the others do so too. And
each agrees to abide by majority rule. So they institute a government with political power, which
Locke defines as
a right of making laws, with penalties of death, and
consequently all less penalties for the regulating
and preserving of property, and of employing the
force of the community in the execution of such
laws, and in the defence of the commonwealth from
foreign injury, and all this only for the public good.
(Gov’t, II, I, 3; p. 118)
Note that Locke assumes that there is such a
thing as property before there is a government;
in fact, one of the chief functions of a government
is to guarantee persons security in the enjoyment
of their property.* But property entails rights; for
something to be your property means that you have
a right to its use and others do not. How could
there be such rights without government?
*It should be noted that Locke uses “property” in a broad
sense to include life and liberty, as well as possessions (see
Gov’t II, IX, 123; p. 180), but he definitely does mean to include possessions as things to which we have a natural right.
*This “labor theory of value” was adopted by the political
economist Adam Smith and used by Karl Marx in his critique
of capitalism. Marx, of course, does not agree that private
property is a natural right. See pp. 540–541.
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a Society of Men constituted only for the procuring, preserving, and advancing of their own Civil
Civil Interests I call Life, Liberty, Health, and
Indolency of Body; and the Possession of outward
things, such as Money, Lands, Houses, Furniture,
and the like.
It is the Duty of the Civil Magistrate, by the
impartial Execution of equal Laws, to secure unto
the People in general, and to every one of his Subjects in particular, the just Possession of these things
belonging to this Life. (Toleration, p. 26)
A church, on the other hand, is
a voluntary Society of Men, joining themselves together of their own accord, in order to the publick
worshipping of God, in such a manner as they judge
acceptable to him, and effectual to the Salvation of
their Souls. (Toleration, p. 28)
Locke argues that it is not the business of the
civil authorities to prescribe the way in which God
is to be worshipped; they have no wisdom in this
sphere. Nor is it appropriate for ecclesiastical authorities to try to gain worldly power. For this
reason the civil power is obliged to tolerate differences in the ways men seek to relate to God and
organize their worship.
Locke piles up a variety of arguments in favor
of religious toleration by the state. Here is an
influential one. It is said that religious dissenters
from the established church are dangerous to civil
order, that they breed sedition and rebellion. Historically, there was truth to this. But, Locke asks,
why is this? It is because they are adversely discriminated against by the civil authority that they are a
threat to that authority. Take away their oppression, and they will be as loyal as any other subjects.
It is not the diversity of Opinions, (which cannot
be avoided) but the refusal of Toleration to those
that are of different Opinions, (which might have
been granted) that has produced all the Bustles and
Wars, that have been in the Christian World, upon
account of Religion. (Toleration, p. 55)
If we in the West now take such toleration and religious liberty pretty much for granted, we owe a
debt of gratitude to Locke as much as to anyone
the executive, to enforce the laws and protect the
commonwealth against external enemies. It is most
important, however, not to think of these powers
as having the ultimate or supreme authority in a
community. They are established by the people for
certain ends, so they exist by the will of the people—
and only for so long as they serve those ends.
The legislative power, Locke says,
being only a fiduciary power to act for certain ends,
there remains still in the people a supreme power to
remove or alter the legislative, when they find the
legislative act contrary to the trust reposed in them.
For all power given with trust for the attaining an
end being limited by that end, whenever that end
is manifestly neglected or opposed, the trust must
necessarily be forfeited, and the power devolve
into the hands of those who gave it, who may place
it anew where they shall think best for their safety
and security. And thus the community perpetually
retains a supreme power of saving themselves from
the attempts and designs of anybody, even of their
legislators, whenever they shall be so foolish or so
wicked as to lay and carry on designs against the
liberties and properties of the subject. (Gov’t, II,
XIII, 149; p. 192)
It was thoughts like these that inspired the American revolutionaries in the late eighteenth century
and laid the foundations for the Constitution of the
United States of America.
Of Toleration
We conclude our brief consideration of Locke’s
thinking with a look at another influential view
of his, concerning religious toleration. In Locke’s
day, political struggles were entangled with religious quarrels. If the king was Roman Catholic, he
sought to enact privileges for Catholics and restrictions on Anglicans. If Parliament was dominated
by the Church of England, it decreed penalties on
dissenters—Baptists, Presbyterians, and Quakers.
Wars were fought over such issues. So while in
exile in Holland, Locke wrote A Letter Concerning
Toleration, which did more to change that situation
than anything else ever did.
He draws a distinction between the civil
commonwealth and a church. The commonwealth is
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1. Things exist independent of our perceiving that
they do.
2. Things have the qualities they seem to have:
The rose we see is really red, the sugar on our
tongue is really sweet, and the fire we approach
is really hot.
Surely he is right that before we study philosophy,
this is what we do think. Berkeley wants to defend
our natural belief in both these claims.
Let us try to get a sense for why he thinks they
need defending. According to Locke, material substances do exist independent of our perception
of them. Moreover, they have qualities of their
own—the primary qualities of extension, figure,
solidity, and motion. However, Locke insists that
the true nature of substance is unknowable. Berkeley asks, How does this differ from skepticism?
Furthermore, we have seen that Galileo, Descartes, and Locke deny the second principle and
hold that color, taste, and feeling are not in things
at all! They exist only in us, as a result of the action
1. How does Locke’s notion of a state of nature differ
from Hobbes’ notion?
2. What are the “inconveniences” in a state of nature
that lead to the formation of a government?
3. Why can’t Locke adopt Hobbes’ view of an absolute
sovereignty as the solution for these problems?
4. What is the origin of private property, according to
5. What sort of government does Locke recommend?
6. How does Locke distinguish the two spheres of
church and state?
7. Why should governments be tolerant of religious
George Berkeley: Ideas into Things
Born near Kilkenny, Ireland, George Berkeley
(1685–1753) became a cleric and later a bishop. At
the youthful age of fifteen, he entered Trinity College, Dublin, where he became acquainted with
the latest science of the day, including the work
of Isaac Newton, and with Locke’s Essay Concerning
Human Understanding. He had a decidedly negative
reaction to much in the Essay. He came to think that
the doctrines Locke taught were mistaken in their
fundamentals and pernicious in their effects. In
short, Berkeley thought Locke’s views led directly
to the errors of skepticism and the evils of atheism. By
his mid-twenties he had worked out a view that he
believed would save us from these two errors. It is
a view, moreover, that allows Berkeley to present
himself as a determined defender of common sense
against the meaningless jargon of the philosophers
and the unnecessary materialism of the scientists.*
Perhaps the best place to begin is with a characterization of common sense, as Berkeley understands it. Two principles characterize what we
might call commonsense realism about the world.5
*Not everyone agrees that Berkeley’s views are harmonious with commonsense views of the world. In some
respects they obviously are; in others, perhaps they are not.
You will have to make up your own mind. His philosophy
is set forth mainly in two small, clearly written books: The
Principles of Human Knowledge (1710) and the charming Three
Dialogues between Hylas and Philonous (1713).
“What do we perceive besides our own ideas or sensations?”
–George Berkeley
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there is no one particular colour wherein all men
partake. So likewise there is included stature, but
then it is neither tall stature, nor low stature, nor
yet middle stature, but something abstracted from
all three. (Principles, Intro, 9; p. 10)
What kind of idea can this be—with a color
that is no particular color and a height that is no
specific height? It seems to embody a contradiction.
Berkeley is certain he has no such ideas and asks us
to examine and see whether we do.*
Moreover, once you allow abstract ideas,
where do you stop? The idea of a material substance is clearly an abstract idea. It is constructed to
play the role of substratum for qualities that need
such support. Because such qualities are of widely
different kinds—inanimate, animal, and human,
for instance—the idea of a substance has to be the
idea of something neither animate nor inanimate,
neither human nor nonhuman—and yet all these
at once. Is it even possible that there should be such
ideas? Berkeley thinks not.
The idea of existence, too, is supposed to be an
abstract idea. So we think we have an idea that substances exist, even though substances lie beyond
all possible experiencing. We also suppose that we
have abstract ideas of the extension, motion, and
solidity of those substances. But these would have
to be ideas of an object having some size, but no
determinate size; moving at some speed, but no
specific speed; and so on. Do we have—could we
have—such ideas?
Berkeley actually quotes a passage from Locke
to illustrate his point that abstract ideas are impossible. Locke says,
*In asking ourselves this question, we must keep in mind
that Berkeley agrees with Locke that the origin of all our
ideas is in sensation or reflection. Whatever other ideas we
have are derived from that source as pale copies or images of
sensation. So we are being asked whether we have an image
of something colored, but without any particular color.
You probably have to confess that you do not. Whether
such images exhaust what we can properly mean by “ideas,”
however, is an important question. If they do not, perhaps
abstract ideas are not in such disrepute as Berkeley claims.
See Kant on the distinction between intuitions and concepts,
pp. 473–474.
of material things on our senses. According to
them, the rose is not literally red; in reality, it is
an uncolored extended substance with a power to
produce a sensation of red in us.
But this means that the accepted philosophical
view denies one of these two commonsense claims
and flirts with skepticism about the other. Furthermore, Berkeley thinks the arguments for that view
are a tissue of confusions. With respect to views
such as Locke’s, Berkeley comments, “We have
first raised a dust and then complain we cannot see”
(Principles, Intro, p. 8).6
Berkeley, then, sets himself to defend common
sense. But you will be surprised at the way he does it.
Abstract Ideas
At the root of the confusion into which Berkeley
believes modern philosophy has fallen is what he
calls “Abuse of Language.” In particular, philosophers have not understood how general terms
work. That we have words general in their meaning
is beyond doubt; most words are like that—tiger,
snow, woman, rainbow, planet, wood, word, and
so on. But in what does their universality consist?
Locke tells us that general words function as
names for abstract ideas. So the word “tiger” stands
not for this tiger or that one, or for the idea of this
or that particular tiger, but for the abstract idea of
a tiger. And we get the abstract idea of a tiger by
selective attention, focusing on only those features
of a thing that make it a tiger, or by noting what
particular tigers have in common.
To Berkeley, this is just nonsense. A “chief part
in rendering speculation intricate and perplexed,”
producing “innumerable errors and difficulties in
almost all parts of knowledge,” is
the opinion that the mind hath a power of framing
abstract ideas or notions of things. (Principles, Intro,
6; p. 9)
We are supposed to be able to look at Peter, James,
and John and abstract from them the idea of man.
But then, Berkeley notes, in this idea
there is included colour, because there is no man
but has some colour, but then it can be neither
white, nor black, nor any particular colour, because
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not appear to me that those notions are formed by
abstraction in the manner premised—universality, so
far as I can comprehend, not consisting in the absolute, positive nature or conception of anything, but
in the relation it bears to the particulars signified
or represented by it; by virtue whereof it is that
things, names, or notions, being in their own nature
particular, are rendered universal. (Principles, Intro,
15; pp. 15–16)
The word “tiger,” then, has a universal significance not because it stands for an abstract idea of
a tiger (there is no such idea), but because we use
those letters or sounds to refer indifferently to any
tiger at all. It is an abuse of language to think that
all words have to be names, like “Socrates,” and that
they must name ideas that are abstract. To think so
is just part of that dust we raise that makes it hard
for us to see.
Another part of the dust, closely connected to
abstract ideas, is Locke’s view that the sole function
of language is to communicate ideas from my mind
to yours—that it is a kind of code for transporting ideas across an otherwise incommunicable gap.
Berkeley says there are two things wrong with that.
First, even where words are names that stand for
ideas, it is not necessary that these ideas be brought
to mind on every occasion of their use.
Second, it is a mistake to think that language is
restricted to the function of communicating ideas.
There are other ends, as the raising of some passion,
the exciting to or deterring from an action, the
putting the mind in some particular disposition. . . .
Even proper names themselves do not seem always
spoken with a design to bring into our view the
ideas of those individuals that are supposed to be
marked by them. For example, when a schoolman tells me Aristotle hath said it, all I conceive he
means by it is to dispose me to embrace his opinion
with the deference and submission which custom
has annexed to that name. (Principles, Intro, 20;
pp. 19–20)
Language has multiple functions, then, the
communicating of ideas being just one. And even
when that is what I intend to do, I cannot communicate to you my abstract ideas because there
aren’t any. Words for them—including “material
substance”—are just meaningless noise.
when we nicely reflect upon them, we shall find
that general ideas are fictions and contrivances of the
mind, that carry difficulty with them, and do not so
easily offer themselves as we are apt to imagine. For
example, does it not require some pains and skill to
form the general idea of a triangle, . . . for it must
be neither oblique nor rectangle, neither equilateral, equicrural, nor scalenon; but all and none of
these at once. In effect, it is something imperfect,
that cannot exist; an idea wherein some parts of
several different and inconsistent ideas are put together. (Essay, IV, VII, 9; vol. 2, p. 274)
Berkeley could only wonder why Locke himself did
not jettison such a monster.
Berkeley does not, of course, deny that we
have general words. We may even have general
ideas, Berkeley says. But these are not abstract general ideas. Their generality lies in the way we use
them, not in their intrinsic nature. He gives an example. Suppose a math teacher is showing you how
to bisect a line using intersecting arcs. She draws a
line on the chalkboard. Then she takes a piece of
string with chalk attached to one end of it and cuts
two arcs, the first with the fixed point at one end of
the line and the second with the fixed point at the
other end. Then she takes a straightedge and connects the points of intersection in the arcs. Notice
that what you have in your perception of this performance is completely particular. It is an image of
one specific line and two arcs. But the point is completely general: This method will work for lines of
any length.
Suppose you ask, How do we know that the
method will work for lines of other lengths, since
you have only demonstrated it for a line of this
given length? Berkeley replies that we know it will
work for other lines because there is nothing in the
demonstration that depends on the length of this
line. The length is arbitrarily chosen, so it doesn’t
matter what it is. So it will work for any line at all.
The example shows how universality works
in our words and ideas. Nowhere do we need to
appeal to abstract ideas. Every word and every idea
can be as particular as that line.
It is, I know, a point much insisted on, that all
knowledge and demonstration are about universal
notions, to which I fully agree: but then it does
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from them, wherein they exist, or, which is the
same thing, whereby they are perceived—for the
existence of an idea consists in its being perceived.
(Principles, I, 2; p. 24)
Here we have Locke’s spiritual substance. Note that
Berkeley says we do not, strictly speaking, have an
idea of it, yet the mind or spirit or soul is so evident
to us at every moment that it cannot be doubted.
If ideas are what we have, spirit is what has them.
Berkeley sometimes says that though we do not
have an idea of it, we do have a notion of spirit.
So far, then, we have two kinds of items in our
inventory of reality: spirits and their ideas. Berkeley boldly claims that that’s all there is. Whatever
exists is either a mind or an idea in such a mind.
And Berkeley thinks he can show us that anything
else is strictly inconceivable—that is, involves a
But ask yourself: Is that what you commonsensically believe? We doubt it! Surely this violates
principle 1 (mentioned earlier) which says that
things exist independent of our minds. So it looks
like Berkeley violates common sense as clearly as
Locke does. If we are to understand Berkeley, we
have to solve this puzzle. We need to answer three
questions: (1) How is Berkeley’s view consistent
with common sense? (2) How does it defeat skepticism? and (3) How does it kill atheism?
The first point to note is that Berkeley insists
that ideas exist only as perceived. He thinks that this
will be evident to us if we just pay attention to what
we mean when we say something exists.
The table I write on I say exists, that is, I see and
feel it; and if I were out of my study I should say it
existed—meaning thereby that if I was in my study
I might perceive it, or that some other spirit actually does perceive it. There was an odour, that is, it
was smelt; there was a sound, that is, it was heard;
a colour or figure, and it was perceived by sight or
touch. This is all I can understand by these and the
like expressions. For as to what is said of the absolute existence of unthinking things without any relation to their being perceived, that is to me perfectly
unintelligible. Their esse is percipi, nor is it possible
they should have any existence out of the minds or
thinking things which perceive them. (Principles,
I, 3; p. 25)
He that knows he has no other than particular ideas,
will not puzzle himself in vain to find out and conceive the abstract idea annexed to any name. And he
that knows names do not always stand for ideas will
spare himself the labour of looking for ideas where
there are none to be had. (Principles, Intro, 24; p. 22)
In these reflections, Berkeley sounds quite contemporary, playing notes that help constitute familiar melodies in twentieth-century philosophy of
Ideas and Things
If the problem is abuse of words, the solution must
be a careful use of words. If the notion of abstract
ideas has led philosophers astray, we must adhere
strictly to nonabstract ideas. Berkeley does not see
this as jettisoning Locke’s whole approach. He endorses Locke’s empiricism, but thinks that Locke
did not stick to it rigorously enough. Berkeley is
determined to be more consistent.†
It is evident to anyone who takes a survey of the objects of human knowledge, that they are either ideas
actually imprinted on the senses; or else such as are
perceived by attending to the passions and operations of the mind; or lastly, ideas formed by help of
memory and imagination. (Principles, I, 1; p. 24)
Here we have Locke’s simple ideas of sensation and
reflection, together with complex ideas we put together as we like. Note that Berkeley also agrees
with Locke that these ideas are the objects of our
In addition to these ideas, however,
there is likewise something which knows or perceives them; and exercises divers operations, as
willing, imagining, remembering, about them. This
perceiving, active being is what I call mind, spirit,
soul, or myself. By which words I do not denote
any one of my ideas, but a thing entirely distinct
*See the discussion regarding analytic and ordinary
language philosophy in Chapter 26. See also the aims of phenomenology in Chapter 27, pp. 655–657.
†It is traditional to see Locke, Berkeley, and Hume as
three philosophers who more and more thoroughly apply
empiricist principles in philosophy. This is a bit too schematic to be wholly correct, but there is a lot of truth in it.
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by sense? and what do we perceive besides our own
ideas or sensations? and is it not plainly repugnant
that any one of these, or any combination of them,
should exist unperceived? (Principles, I, 4; p. 25)
What is the contradiction in thinking that sensible things exist unperceived? Let us set out the
argument, using the table as an example.
1. A table is a sensible thing.
2. Sensible things are perceived by sense.
3. Whatever is perceived by sense is a sensation.
4. No sensation can exist unperceived.
5. So, no table can exist unperceived.
6. So, to say that a table exists even when not perceived is to say, This table, which exists only as
perceived, exists unperceived.
And 6 is self-contradictory. Berkeley holds that it
is only because of the confused doctrine of abstract
ideas that we can separate existence from appearance in our experience.
You may still not be convinced. In particular, you
may balk at proposition 3 in the preceding argument.
You may say that you do perceive tables by means of
your senses, but what you perceive that way is not a
sensation—it is a thing. And Berkeley would want
to reply that you are partly right and partly wrong.
True, he says, it is indeed a thing you sense. That
part is right. But you are wrong if you assume that
a thing exists independent of perception. For what
do we mean by the term “thing”? If this is to be a
meaningful term, it must be filled out in terms of
experience. And what do we experience the table as?
Well, for one thing, we experience a table as
colored. But the philosophers have demonstrated
that neither color nor any other secondary quality
can exist independent of us. It is too variable, too
dependent on the light, the condition of the eyes,
and the proper functioning of the nervous system to
be a property of the thing. Berkeley presents a wellknown experiment in his dialogue. Hylas has been
arguing that heat is really present in fire, and Philonous (who usually speaks for Berkeley) replies,*
*The name “Hylas” comes from the Greek word for
matter, hyle. And “Philonous” obviously means lover of mind
or spirit. So Berkeley gives us in the dialogue a conversation
between a would-be materialist and a champion of the spirit.
This is an extremely important set of claims for
Berkeley. Let us make sure we understand what
he is saying. The first claim is that there is no abstract idea of existence, such as might be applied to
things beyond our experience like Locke’s material
substances. The existence (esse) of things consists
in their being perceived (percipi). For ideas, including simple sensations, to be is to be perceived.
To exist is to be experienced. (Actually, Berkeley
should say, and sometimes does say, that to be is
either to be an idea perceived or to be a perceiver of
ideas—a spirit.) The supposition that ideas might
exist on their own, apart from a knower, Berkeley
claims to be “unintelligible.”
The second thing to note is that Berkeley talks
about “the table I write on.” Now a table, we usually
think, is a thing, not an idea. But its inclusion here
is not, as you might suspect, a slip on his part. For
Berkeley, the table is also an idea—or rather, a complex of ideas presented to the various senses, sight and
touch predominantly. So the table as experienced has
its being only in being perceived. We will examine
Berkeley’s argument for this claim subsequently.
Third, note that Berkeley says of the table,
when it is not in my presence, that its existence
consists in its being either actually perceived by
another spirit or in a hypothetical condition such
as this: If you were in your study, then you would
perceive it. In fact, Berkeley thinks both halves of
this disjunction are the case. If your table actually
exists in your absence, then it is being perceived by
another spirit, and it is true that if you were there
in your study, you would perceive it. (This will
become clearer in a moment.)
But a table is a thing, we say. What can we
make of Berkeley’s claim that it is an idea? Here is
the argument:
It is indeed an opinion strangely prevailing amongst
men that houses, rivers, and in a word all sensible
objects, have an existence, natural or real, distinct
from their being perceived by the understanding.
But, with how great an assurance and acquiescence
soever this principle may be entertained in the
world, yet whoever shall find it in his heart to call
it in question may, if I mistake not, perceive it to
involve a manifest contradiction. For, what are the
forementioned objects but the things we perceive
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vary continuously in both size and shape. Wherever did you get the idea that the size of the paper
was something constant and unchanging, a given
absolute property of the paper? Not from any experience you ever had. All you know of the paper
is supplied by your experience; and nothing in that
experience testifies to such a permanent and immutable property. It must be that the idea you think
you have of the paper’s extension is an abstract idea.
But there are no abstract ideas, so you don’t really
have a proper idea of that at all! To talk about an
objective, mind-independent, absolute property
of extension is just meaningless jargon, an empty
abuse of words.
In this way Berkeley argues that the distinction
between secondary and primary qualities breaks
down. What is true of the former is true also of the
latter: They too have their being only in being perceived. But now we may begin to feel dizzy. What
has happened to our familiar world? It looks as
though all the everyday, stable, commonsense, dependable things we thought we were dealing with
have been dissolved into a giddy whirl, where nothing remains the same from moment to moment—a
chaos of changes. It looks as though the world has
been lost, and all we are left with is a flux of evershifting sensations.
But at this point, Berkeley, the defender of
common sense, comes back and says,
I do not argue against the existence of any one thing
that we can apprehend either by sense or reflection.
That the things I see with my eyes and touch with
my hand do exist, really exist, I make not the least
question. The only thing whose existence we deny
is that which philosophers call matter or corporeal
substance. And in doing of this there is no damage
done to the rest of mankind, who, I dare say, will
never miss it.
. . .
If any man thinks this detracts from the existence or reality of things, he is very far from understanding what hath been premised in the plainest
terms I could think of.
. . .
. . . if the word substance be taken in the vulgar
sense—for a combination of sensible qualities, such
as extension, solidity, weight, and the like—this we
PHIL.: Can any doctrine be true that necessarily leads a
man into an absurdity?
HYL.: Without doubt it cannot.
PHIL.: Is it not an absurdity to think that the same thing
should be at the same time both cold and warm?
HYL.: It is.
PHIL.: Suppose now one of your hands hot, and the
other cold, and that they are both at once put into
the same vessel of water, in an intermediate state;
will not the water seem cold to one hand, and
warm to the other?
HYL.: It will.
PHIL.: Ought we not therefore, by our principles, to
conclude it is really both cold and warm at the same
time, that is, according to your own concession, to
believe an absurdity?
HYL.: I confess it seems so.
PHIL.: Consequently, the principles themselves are
false, since you have granted that no true principle
leads to an absurdity.
—Dialogues, pp. 115–116
The principle proved false by this experiment is
that secondary qualities have an existence outside
the mind that perceives them. The same goes for all
such qualities, including the color of the table. For
secondary qualities, then, the tradition has it right:
To be is to be perceived.
But you, having learned of the distinction between secondary qualities and primary qualities,
now say, “That may be true of the color of the
table, but its size, its extension, its solidity—these
qualities it really has. These qualities may be represented by ideas in my mind, but their existence is
not percipi.” But Berkeley and his alter ego, Philonous, argue that whatever goes for odors, tastes,
colors, sounds, and textures goes also for the primary qualities of extension, solidity, and motion.
Let’s take the argument concerning extension as
illustrative. Take a piece of paper and lay it on the
desk before you. Then move around it, looking
at it from this angle, now that. Move away from
it, then close. Then very, very close. Pay careful
attention to your experience of what we call “the
paper.” Is there anything in that experience that
remains constant from one moment to the next?
No, the ideas or sensations you are provided with
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when I put my hand near a fire. With respect to my
sensations (which are, remember, the origin of all
my ideas) I am passive.
2. Moreover, ideas are inert. That is, they are
causally inactive. It is never the case that one idea
causes another idea to appear. What Berkeley has
in mind here is this: The sensation of water boiling
is not caused by the sensation of the kettle on the
fire. True, the one follows the other with regularity, according to the laws of nature. But this just
shows that the laws of nature are not causal laws.
They don’t tell us that x causes y; they just describe
the uniformities in our experience: Kettles left on
a fire long enough are followed by water boiling.
The connexion of ideas does not imply the relation of cause and effect, but only of a mark or sign
with the thing signified. The fire which I see is not
the cause of the pain I suffer upon my approaching it, but the mark that forewarns me of it. In like
manner the noise that I hear is not the effect of this
or that motion or collision of the ambient bodies,
but the sign thereof. (Principles, I, 65; p. 52)
Sensations and ideas, then, do not act. (Berkeley
takes this as an additional proof that a secondary
quality such as color could not be caused in us by
primary qualities such as extension and motion; no
such qualities are causes!)
3. Do we have any experience, then, of something with causal power? Yes, virtually every
moment of our lives. I stand, I sit, I raise my arm,
I walk, I write. In all these ways activity is evident—
the activity of the will. We have been thinking
almost exclusively of ideas or things (things being
just ideas that are connected in the right ways). And
the constant theme has been that their being consists
in their being perceived. But we must now turn our
attention to the perceivers of these ideas. Spirits
are not merely passive receivers of sensations; they
also have control over some of their ideas—and
even over some sensations. Not only can I decide
to recall the capital of Ohio and (usually) do so, but
also I can also decide to move my finger and (usually)
my finger moves. The finger—that combination of
ideas we call “a finger”—does not itself contain any
powers or causal energies; Berkeley takes it that he
has proved that. But my will does. True, I cannot
cannot be accused of taking away; but if it be taken
in a philosophic sense, for the support of accidents
or qualities without the mind, then indeed I acknowledge that we take it away, if one may be said
to take away that which never had any existence,
not even in the imagination. (Principles, I, 35, 36,
37; pp. 38–39)
Does the paper on your desk really exist? Yes,
says Berkeley. Of course. In fact, it exists with
all those qualities that it seems to have—just that
whiteness, that combination of shapes, that coolness to the touch, that flexibility, and so on that
you perceive it to have. The piece of paper is not
a mysterious something behind or beyond our experience of it but is itself just a combination of the
qualities we attribute to it. We call such a combination that is regularly ordered by the laws of nature
“a thing,” or “a substance,” and that’s the only sense
the term “thing” could meaningfully have for us.
This is the way Berkeley defends the second principle of common sense: that things have just the
properties they appear to have.
Still, we may have an uneasy feeling, expressed
clearly by a question Hylas asks in the dialogues:
“Can anything be plainer than that you are for
changing all things into ideas?” (Dialogues, III,
p. 188). But to this Philonous replies,
You mistake me. I am not for changing things into
ideas, but rather ideas into things; since those immediate objects of perception, which, according
to you, are only appearances of things, I take to be
the real things themselves. . . . In short, you do not
trust your senses, I do. (Dialogues, III, p. 188)
But we still may not be satisfied. How can
Berkeley avoid the charge that he destroys the
independent existence of things, making them
wholly relative to our perceiving of them? That is,
can he show that principle 1 (cited at the outset of
this section) is also true on his account—that things
do exist independent of our perceiving them? He
makes several points.
1. He echoes Descartes, Locke, and others in
observing that while I can, in my imagination, arrange ideas pretty much as I like, I cannot do that
with my senses. What I see when I open my eyes is
not in my control. I cannot decide not to feel heat
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necessarily by us. Since we are not in control of
the course of those ideas we call the world, and yet
they must exist in a spirit, it follows that there must
be a spirit in which these ideas exist and which produces them in us. So, Berkeley thinks, if we get
our epistemology and metaphysics straight, we are
presented with a new and extremely simple proof
for the existence of God.
You know your own existence as a spirit by
a kind of immediate intuition. You know your
friends’ existence only indirectly. That is, you observe in the course of your experience certain conjunctions of sensations, which act as a sign of the
presence of other finite spirits like yourself; to put
it colloquially, some of what you observe you take
to be behavior expressing other minds.
But, though there be some things which convince
us human agents are concerned in producing them,
yet it is evident to every one that those things which
are called the Works of Nature—that is, the far
greater part of the ideas or sensations perceived by
us—are not produced by, or dependent on, the
wills of men. There is therefore some other Spirit
that causes them; since it is repugnant that they
should subsist by themselves. . . . But, if we attentively consider the constant regularity, order,
and concatenation of natural things, the surprising
magnificence, beauty and perfection of the larger,
and the exquisite contrivance of the smaller parts of
the creation, together with the exact harmony and
correspondence of the whole . . . and at the same
time attend to the meaning and import of the attributes One, Eternal, Infinitely Wise, Good, and
Perfect, we shall clearly perceive that they belong
to the aforesaid Spirit, “who works all in all,” and
“by whom all things consist.” (Principles, I, 146,
pp. 139–140)
So we see how Berkeley means to support commonsense principle 1 as well as 2. Principle 1 says
that things have a reality independent of our perceiving them—and so they do. Theirs is not the reality of material substance, however, but the reality
of ideas perceived by an infinite Spirit. Given the
difficulties attaching to the idea of matter, together
with the apparent impossibility of explaining how
matter can cause ideas in us, this might seem like
a good trade. After all, we do have a clear notion,
decide what I will see when I open my eyes, but I
decide when to open them. Here, in spirit or mind,
which we know not by sense but by reflection, we
discover causal power. Philonous says,
How often must I repeat, that I know or am conscious of my own being; and that I myself am not
my ideas, but something else, a thinking, active
principle that perceives, knows, wills, and operates
about ideas? I know that I, one and the same self,
perceive both colours and sounds: that a colour
cannot perceive a sound, nor a sound a colour: that
I am therefore one individual principle, distinct
from colour and sound; and for the same reason,
from all other sensible things and inert ideas.
(Dialogues, III, p. 176)
I have no notion of any action distinct from
volition, neither can I conceive volition to be
anywhere but in a spirit; therefore, when I speak
of an active being, I am obliged to mean a spirit.
(Dialogues, III, pp. 182–183)
And now we are near the point where Berkeley
thinks that his way of looking at things refutes atheism. What makes atheism both possible and attractive, Berkeley holds, is the hypothesis of matter
or corporeal substance as the bearer of real existence. We do need to explain the regular, uniform
course that our sensations take, and matter seems
to provide an explanation. The reason we see what
we see, hear what we hear, and touch what we
touch is that there is an objectively existing, material world out there affecting us, producing these
sensations in our minds. But if it is matter that is
doing it, who needs God?
But we have seen that Berkeley has argued
that the abstract idea of a material substance independent of mind is a grotesque construction,
full of contradiction. And in any case, the qualities we are acquainted with in sensation are none
of them causes. So materialism is broken-backed as
an explanation for the course of our experience. It
cannot do the job it is supposed to do.
We do, however, need an account of why our experience is as regular and well-ordered as it is. For
a sensation to be is for it to be perceived—but not
George Berkeley: Ideas into Things 435
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You have probably noticed something that Hylas
also remarks about near the end of his dialogue
with Philonous. All along, it has been Philonous
who has been trotting out arguments characteristic
of the skeptics, showing again and again how anything we perceive is relative to the perception of
it—how it has no objective, absolute existence at
all. Then at the end, like a judo master, he turns
the tables, using the strength of the skeptical arguments against themselves to show that what, on
traditional principles, was merely appearance is in
fact the reality itself!
Skepticism, then, is refuted in virtue of the
fact that the things of our experience are actually
just as we perceive them to be. And atheism is refuted in virtue of these things having a necessary
dependence on God. Common sense is vindicated,
Berkeley believes, in both its main tenets. And
he considers himself to be altogether successful
in dispelling the dust that previous philosophers’
thoughts had raised, leaving us with a clear and coherent vision of things.
1. What two principles of common sense does
Berkeley hope to defend?
2. How does the distinction between primary and
secondary qualities undermine common sense?
3. Why does Berkeley think that abstract ideas are
4. How, according to Berkeley, do general words
and ideas work?
5. What’s wrong with the notion that language is for
the communication of ideas?
6. In what basic way does Berkeley agree with Locke,
despite his criticisms?
7. Explain the slogan that “esse is percipi.”
8. What does it mean, for Berkeley, that your bicycle
exists even when neither you nor any other person
is observing it?
9. What does he say we must mean when we use the
word “thing”?
10. What is the argument that shows that the existence
of primary qualities is percipi just as truly as is the
existence of secondary qualities?
11. What does it mean to say ideas are “inert”?
12. Where do we experience causal power?
13. Why does God need to be brought into the
Berkeley assures us, of an active mind or self, and
we do need an account of the regular course of
nature. The providential guidance of an Almighty
Spirit is near at hand to supply it.
We can perhaps sum up Berkeley’s argument
in this way:
1. The regular succession of changes in ideas must
be caused by either
a. the ideas themselves;
b. material substances;
c. some other finite Spirit, such as yourself; or
d. God.
2. Not a, for ideas, unlike spirits, are inert and
have no causal power.
3. Not b, since material substances are (necessarily) nonexistent.
4. Not c, because you and all other finite spirits are
largely passive with respect to this succession.
5. So d, and this succession is caused to be what it
is because it is perceived by an infinitely powerful Spirit, which (as Aquinas might say) we all
call God.
Thus we have an answer to an obvious question: If to be is to be perceived, what happens to
my desk when I’m not perceiving it? Does it jump
in and out of existence when I open and close my
eyes? No, of course not. It continues to exist in
both of those senses we distinguished earlier: the
hypothetical sense (If I were to open my eyes, then
I would perceive it) and the absolute sense (It is all
the while being perceived by God).
This feature of Berkeley’s thought has been memorialized in a pair of limericks.7
There was a young man who said, “God
Must think it exceedingly odd
If he finds that this tree
Continues to be
When there’s no one about in the Quad.”
Dear Sir:
Your astonishment’s odd;
I am always about in the Quad.
And that’s why the tree
Will continue to be,
Since observed by
Yours faithfully,
436 CHAPTER 18 Hobbes, Locke, and Berkeley: Materialism and the Beginnings of Empiricism
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simple idea
complex ideas
primary qualities
secondary quality
personal identity
real essence
nominal essences
natural law
common sense
abstract ideas
1. Quoted in Objections III with Replies in The
Philosophical Works of Descartes, vol. 2, ed. Elisabeth
S. Haldane and G. R. T. Ross (n.p.: Dover, 1955),
2. Quotations from Thomas Hobbes, Leviathan, or
The Matter, Form, and Power of a Commonwealth,
Ecclesiastical and Civil, in The English Philosophers
from Bacon to Mill, ed. Edwin A. Burtt (New York:
Modern Library, 1939), are cited in the text
using the abbreviation L. References are to page
3. Margaret Cavendish, Philosophical Letters, or
Modest Reflections upon Some Opinions in Natural
Philosophy Maintained by Several Famous and
Learned Authors of this Age, Expressed by Way of
Letters (London: s.n., 1664), 320–321. Available
online at
4. Quotations from Locke are cited as follows:
Essay: An Essay Concerning Human Understanding, ed.
Alexander Campbell Fraser (New York: Dover,
1959), by book, chapter, and section number,
followed by the volume and page number in this
Gov’t: Of Civil Government, Two Treatises (London:
J. M. Dent and Sons, 1924), cited by book,
chapter, and section number, followed by the
page number in this edition.
Toleration: A Letter Concerning Toleration (Indianapolis,
IN: Hackett, 1983).
5. We are indebted to A. C. Grayling, who frames
the puzzle of Berkeley’s commonsense claims in
14. How is skepticism defeated?
15. How is atheism defeated?
16. Sketch the argument by which Berkeley would
claim to be a defender of common sense.
1. Write a dialogue in which Descartes and
Hobbes (who were contemporaries and met at
least once) debate about the nature of human
2. Imagine that your soul left your body and went
to heaven, but your consciousness (including
your memories and your basic character traits)
remained here on earth in your body. Where
would you be? Why? (Or couldn’t you imagine
that? Why not?)
3. Berkeley says that a thing—your left running
shoe, for instance—is just a combination of
ideas. We doubt that you believe this. Try to
construct a critique of this claim that doesn’t
allow Berkeley an immediate comeback.
resolution and
regulated thoughts
vital motions
voluntary motions
state of nature
law of nature
right of nature
social contract
innate ideas
George Berkeley: Ideas into Things 437
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Principles, by book and section number, followed by
the page number in this edition
Dialogues, by page number in this edition
7. In Bertrand Russell’s History of Western Philosophy
(London: Allen and Unwin, 1946), 623; Russell
attributes it, or at least the first stanza, to Ronald Knox.
this way in his book Berkeley: The Central Arguments
(London: Duckworth, 1986).
6. Quotations from Berkeley are from George Berkeley:
Principles of Human Knowledge and Three Dialogues,
ed. Howard Robinson (Oxford: Oxford University
Press, 1996), cited as follows:
mel70610_ch19_438-464.indd 438 07/09/18 03:57 PM
Unmasking the Pretensions of Reason
he eighteenth century is often called the age
of enlightenment. Those who lived through
this period in Europe and some of its colonies felt they were making rapid progress toward
overthrowing superstition and arbitrary authority,
replacing ignorance with knowledge and blind obedience with freedom. It is an age of optimism. One
of the clearest expressions of this attitude is found
in a brief essay by Immanuel Kant (the subject of
our next chapter). Writing in 1784, Kant defines
what the age understands by “enlightenment.”
Enlightenment is man’s emergence from his self-imposed
immaturity. Immaturity is the inability to use one’s
understanding without guidance from another. This
immaturity is self-imposed when its cause lies not in
lack of understanding, but in lack of resolve and
courage to use it without guidance from another.
Sapere Aude! “Have courage to use your own understanding!”—that is the motto of enlightenment.1
This call to think for oneself, to have the courage to rely on one’s own abilities, is quite characteristic of European thinkers of the age. For Kant,
the lack of courage is “self-imposed.” Working
oneself out of this immaturity is difficult, Kant
says, but not impossible—as had been clearly
shown in the triumphs of the scientific revolution
from Copernicus to that most admired of thinkers, Isaac Newton (1642–1727). Newton’s unified
explanatory scheme for understanding both terrestrial and celestial movements symbolized what
human efforts could achieve—if only they could be
freed from the dead hand of the past. And thinkers
throughout the eighteenth century busy themselves
applying Newton’s methods to other subjects: to
the mind, to ethics, to religion, and to the state
of society.
Yet none of them would claim to have arrived
at the goal. Here again is Kant:
If it is now asked, “Do we presently live in an enlightened age?” the answer is, “No, but we do live in
an age of enlightenment.”2
The key word is “progress.” Newton showed that
progress is really possible. And the conviction spreads
that this progress can be extended indefinitely if only
we can muster the courage to do what Newton had
done in physics and astronomy. We were not yet
mature, but we were becoming mature.
How Newton Did It 439
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How Newton Did It
It is almost impossible to exaggerate Newton’s
impact on the imagination of the eighteenth century. As a towering symbol of scientific achievement, he can be compared only to Einstein in the
twentieth century. The astonished admiration his
work evoked is expressed in a couplet by Alexander Pope.
Nature and Nature’s laws lay hid in night;
God said, Let Newton be, and all was light.*
Everyone has some idea of Newton’s accomplishment, of how his theory of universal gravitation provides a mathematically accurate and
powerful tool for understanding not only the
motions of heavenly bodies but also such puzzling phenomena as the tides. We don’t go into
the details of this theory here, but every science
is developed on the basis of certain methods and
presuppositions that may properly be called philosophical. It is these philosophical underpinnings
that we must take note of, for they are crucially
important to the development of thought in the
eighteenth century—not least to the philosophy
of David Hume.
How had Newton been able to pull it off?
His methods are not greatly different from those
of Galileo and Hobbes. There are two stages (like
Hobbes’ resolution and composition), which he
calls analysis and synthesis. But there is a particular insistence in some of his pronouncements
that strikes a new note.
I frame no hypotheses; for whatever is not deduced
from the phenomena is to be called an hypothesis;
and hypotheses, whether metaphysical or physical,
whether of occult qualities or mechanical, have no
place in experimental philosophy.3
The key to doing science, he believes, is to
stay close to the phenomena rather than to frame
hypotheses. Newton’s long and persistent series
of experiments with the prism exemplifies this
* Epitaph intended for Sir Isaac Newton. John
Bartlett, Familiar Quotations, 14th ed. (Boston: Little,
Brown, 1968).
maxim. The fact that white light is not a simple
phenomenon (as it seems to naive sight) is disclosed
only by an immensely detailed series of investigations, which reveal its composition out of the many
simpler hues of the rainbow.
The explanations of his experiments are to be
“deduced from the phenomena.” This emphasis
on paying attention to the facts of experience is
Aristotelian in character, but in the modern era,
we can trace it back through John Locke to Francis Bacon. In Newton its fruitfulness pays off in
a way that had never been seen before. Newton
expresses a deep suspicion of principles not derived from a close experimental examination of
the sensible facts. We cannot begin with what
seems right to us. Hypotheses not arrived at by
way of careful analysis of the sensible facts are
arbitrary—no matter how intuitively convincing
they may seem. And Newton’s success is, to the
eighteenth-century thinker, proof that his methods are sound.
Note how different this is from the rationalism
of Descartes. Always the mathematician, Descartes
seeks to find starting points for science and philosophy that are intuitively certain, axioms that are
“so clear and distinct” that they cannot possibly be
doubted. He is confident that reason, the “light of
nature,” will certify some principles as both knowable and known. So the structure of wisdom, for
Descartes, is the structure of an axiomatic, geometrical system. Intuitive insight and deduction
from first principles will get you where you want
to go.
But for eighteenth-century thinkers inspired
by Newton, this smells too much of arbitrariness.
One man’s intuitive certainty, they suspect, is another man’s absurdity.* The only cure is to stick
closely to the facts. The rationalism of Descartes is
supplanted by the empiricism of Locke, Berkeley,
and David Hume.
* They feel confirmed in this suspicion by the example
of rationalist philosophy after Descartes. First-rate intellects such as Malebranche, Spinoza, and Leibniz developed
remarkably different philosophical systems on the basis of
supposedly “self-evident” truths.
440 CHAPTER 19 David Hume: Unmasking the Pretensions of Reason
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Born into an aristocratic French family, Émilie
du Châtelet (1706–1749) juggled many
identities during her short life: She was a learned
natural philosopher, a courtier in the palace of
King Louis XV, a member of Parisian high society, and the wife of an ambitious nobleman. She
was also an active participant in the Republic of
Letters, early modern Europe’s intellectual elite,
who shared and debated their ideas through correspondence and publications. Despite the demands
her social role placed on her, she embodied the
advice she set forth in her Discourse on Happiness “to
be resolute about what one wants to be and about
what one wants to do” (DH, 355).4
After studying
philosophy, physics, analytic geometry, and the
newly invented calculus, she published a number
of philosophical treatises and translated Newton’s
Principia Mathematica into French. Her Foundations
of Physics synthesizes Newtonian mechanics with
the ideas of the great German philosopher Leibniz
to set Newtonian science on firmer metaphysical
Du Châtelet grounds all human knowledge
on two basic principles. The first is Aristotle’s
principle of noncontradiction, which says that
something cannot be both true and false at the
same time. Something is impossible, du Châtelet
says, just in case it implies a contradiction. She
warns that many things that seem possible, such as
the largest prime number, are in fact impossible
on careful consideration and that many philosophers have blundered into mistakes by supposing that they have a clear idea of something that
turns out to be impossible. The second principle
is Leibniz’s principle of sufficient reason, which
says that there must be a sufficient reason to
explain why things are as they are.* According
to du Châtelet, the principle of noncontradiction
explains all necessary truths, because denying them
leads to contradiction, but if we want to establish some contingent truth, we need to identify
a sufficient reason that enables us to understand
why things are as they are and not some other
way. Furthermore, these reasons must actually
improve our understanding of the phenomenon.
Otherwise, it is just a meaningless way of claiming that there is some reason.
Acquiring knowledge of contingent facts, du
Châtelet argues, often requires framing hypotheses.
When certain things are used to explain what has
been observed, and though the truth of what has
been supposed is impossible to demonstrate, one
is making a hypothesis. (FP, 148)
Especially at the beginning of an inquiry,
there is often no way to proceed except by framing hypotheses. Doing science well, du Châtelet
says, involves testing those hypotheses against
observations and accepting hypotheses as probable only when they have been confirmed repeatedly and explain a wide range of observations.
This is how astronomy advanced from a primitive
understanding of the skies to Ptolemy’s system to
Copernicus and Kepler’s. Since it is on the basis
of Kepler’s system that Newton showed that the
laws of motion apply to the heavens, du Châtelet
argues, even Newton himself depended on others’
framing and testing of hypotheses. She objects that
whereas natural philosophers in Descartes’ day had
embraced unfounded hypotheses without testing them, building whole systems on “fables” or
“fictions,” thinkers in her own time had swung too
To Be the Newton of Human Nature 441
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far in the other direction by trying to do without hypotheses altogether. Those who refuse to
entertain hypotheses at all, she cautions, will seldom reach the truth.
The true causes of natural effects and of the
phenomena we observe are often so far from
the principles on which we can rely and the
experiments we can make that one is obliged
to be content with probable reasons to explain them. Thus, probabilities are not to be
rejected in the sciences, not only because
they are often of great practical use, but also
because they clear the path that leads to the
truth. (FP, 147)
* On Leibniz, see p. 478.
To Be the Newton
of Human Nature
David Hume (1711–1776) aspires to do for human
nature what Isaac Newton did for nonhuman
nature: to provide principles of explanation both
simple and comprehensive.5
There seem to be two
motivations. First, Hume shares with many other
Enlightenment intellectuals the project of debunking what they call “popular superstition.” By this
they usually mean the deliverances of religious
enthusiasm, together with the conviction of certainty that typically accompanies them.* (The era
of religious wars based on such certainties is still
fresh in their memory.) But they also mean whatever cannot be demonstrated on a basis of reason
and experience common to human beings. Hume’s
prose betrays his passion on this score. Remarking
on the obscurity, uncertainty, and error in most
philosophies, he pinpoints the cause:
They are not properly a science; but arise either
from the fruitless efforts of human vanity, which
would penetrate into subjects utterly inaccessible
to the understanding, or from the craft of popular
superstitions, which, being unable to defend themselves on fair ground, raise these entangling brambles to cover and protect their weakness. Chased
* “Enthusiasm” is the word eighteenth-century thinkers
use to describe ecstatic forms of religion involving the claim
that one is receiving revelations, visions, or “words” directly
from God. This form of religion is far from dead.
from the open country, these robbers fly into the
forest, and lie in wait to break in upon every unguarded avenue of the mind, and overwhelm it
with religious fears and prejudices. The stoutest
antagonist, if he remit his watch a moment, is oppressed. And many, through cowardice and folly,
open the gates to the enemies, and willingly receive
them with reverence and submission, as their legal
But is this a sufficient reason, why philosophers should desist from such researches, and
leave superstition still in possession of her retreat?
Is it not proper to draw an opposite conclusion, and perceive the necessity of carrying the
war into the most secret recesses of the enemy?
(HU, 91–92)6
The basic strategy in this war is to show what
the human understanding is (and is not) capable of.
And this is what a science of human nature should
give us. If we can show that “superstition” claims
to know what no one can possibly know, then we
undermine it in the most radical way.
“Superstition is the religion of feeble minds.”
Edmund Burke (1729–1797)
Hume’s second motivation is his conviction
that a science of human nature is, in a certain way,
fundamental. Because all our intellectual endeavors
are products of human understanding, an examination of that understanding should illumine them
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only by sticking close to the experimental facts; we
can hope to progress in understanding the mind
only if we do the same.
For to me it seems evident, that the essence of the
mind being equally unknown to us with that of external bodies, it must be equally impossible to form
any notion of its powers and qualities otherwise
than from careful and exact experiments, and the
observation of those particular effects, which result
from its different circumstances and situations. And
tho’ we must endeavour to render all our principles
as universal as possible, by tracing up our experiments to the utmost, and explaining all effects from
the simplest and fewest causes, ’tis still certain we
cannot go beyond experience; and any hypothesis,
that pretends to discover the ultimate original qualities of human nature, ought at first to be rejected as
presumptuous and chimerical. (T, Intro, p. 5)
The Newtonian tone is unmistakable. What,
then, are the data that scientists of human nature
all, even mathematics, natural philosophy, and religion. Such an inquiry will reveal how the mind
works, what materials it has to operate on, and how
knowledge in any area at all can be constructed.
Hume is aware that others before him have
formulated theories of the mind (or human understanding), but they have not satisfactorily settled
There is nothing which is not the subject of debate,
and in which men of learning are not of contrary
opinions. . . . Disputes are multiplied, as if every
thing was uncertain; and these disputes are managed
with the greatest warmth, as if every thing was certain. (T, Intro. p. 3)
Consider the wide disagreement between Descartes
and Hobbes, for instance. Descartes, as we have
seen, believes that the freedom and rationality of
our minds exempts them from the kind of causal
explanation provided for material bodies. A mind,
he concludes, is a thing completely distinct from a
body. Hobbes, however, includes the mind and all
its ideas and activities within the scope of a materialistic and deterministic science. “Mind,” for Hobbes,
is just a name for certain ways a human body operates. Who is right here?
From Hume’s point of view, neither one prevails. Hobbes simply assumes that our thoughts represent objects independent of our minds and that
whatever principles explain these objects will also
explain the mind. But surely Descartes has shown us
that this is something we should not assume. Whatever our experience “tells” us about reality, things
could actually be different. That is the lesson of
Descartes’ doubt. Hobbes’ assumption that sensations and thoughts generally represent realities accurately is nothing but a “hypothesis.” And, Hume
says (following Newton), we must avoid framing
hypotheses. Similarly, Descartes’ positive doctrine
of a separate mind-substance is just as “hypothetical” as that of Hobbes. It is derived from principles
that may seem intuitively obvious but have not been
“deduced from the phenomena.”
We do not have, Hume thinks, any insight into
the “essence” of either material bodies or minds, as
Hobbes and Descartes seem to assume. We have
made progress in understanding the physical world
“As the science of man is the only solid foundation for
the other sciences, so the only solid foundation we can
give to this science itself must be laid on experience and
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Hume thinks that we are all familiar with this
difference. There may be borderline cases such as a
terrifying dream, in which the ideas are very nearly
as lively as the actual impressions would be. But
on the whole, the distinction is familiar and clear.
One other important distinction must be observed:
that between simple and complex perceptions. The
impression you have when you slap the table is
simple; the impression you have when you hear
a melody is complex. Complex impressions and
ideas are built up from simple ones.
The next thing Hume notices is “the great resemblance betwixt our impressions and ideas”
(T, I, 1, 1, p. 8). It seems as though “all the perceptions of the mind are double, and appear both
as impressions and ideas” (T, I, 1, 1, p. 8). No, he
adds, this is not quite correct. For you have the
idea of a unicorn, but you have never experienced
a unicorn impression. (Ah, you say; but I have
seen a picture of a unicorn! True enough, but your
experience on that occasion did not constitute an
impression of a unicorn, but that of a unicorn picture. Your idea of a unicorn is not the idea of a
picture.) So you do have an idea that does not correspond to any impression; so not all our perceptions are “double.”
But a closer look, Hume thinks, will convince us
that although this principle does not hold for complex ideas, it does hold for all simple ideas. We
need not analyze the idea of a unicorn very far to
notice that it is made up of two simpler ideas: that
of a horse and that of a single horn. Impressions do
correspond to these simpler ideas, for we have all
seen horses and horns. So the revised principle is
that to every simple idea corresponds a simple impression that resembles it.
If impressions and simple ideas come in pairs
like this, so that there is a “constant conjunction”
between them, the next question is, Which comes
first? Hume again notes that in his experience, it is
always the impression that appears first; the idea
comes later.
To give a child an idea of scarlet or orange, of sweet
or bitter, I present the objects, or in other words,
convey to him these impressions; but proceed not
so absurdly, as to endeavour to produce the impressions by exciting the ideas. . . . We cannot form
must “observe” and from which they may draw
principles “as universal as possible”? Hume calls
them “perceptions,” by which he means all the
contents of our minds when we are awake and
alert.* Among perceptions are all the ideas of the
sciences, as well as ideas arbitrary and superstitious. Hume aims to draw a line between legitimate ideas and ideas that are confused, unfounded,
and nonsensical. The first thing to do is to inquire
about the origin of our ideas.
The Theory of Ideas
A science of human nature must concentrate on
what is peculiarly human. A person’s height,
weight, and shape are characteristics of a human
being, but these are properties shared with the nonhuman objects Newtonian science explains so well.
It is human ideas, feelings, and actions that require
special treatment. Ideas are particularly important
because they are involved in nearly all the activities
that are characteristically human. What are ideas,
and how do we come to have them?
Perceptions, Hume claims, can be divided into
two major classes: impressions and ideas.
The difference betwixt these consists in the degrees of force and liveliness with which they
strike upon the mind, and make their way into
our thought or consciousness. Those perceptions,
which enter with most force and violence, we may
name impressions; and under this name I comprehend
all our sensations, passions and emotions, as they
make their first appearance in the soul. By ideas
I mean the faint images of these in thinking and
reasoning. (T, I, 1, 1 p. 7)
You can get a vivid illustration of the difference between the two classes if you slap the table smartly
with your hand (the sound you hear is an impression) and then, a few seconds later, recall that
sound (the content of your memory is an idea).
*Here Hume shows that he, like Descartes (and Locke
and Berkeley, too), is committed to the basic principle of the
representational theory (pp. 372–373)—that what we know
first and best are our ideas. Unlike Descartes, as we will see,
Hume believes there are no legitimate inferences from ideas
to things.
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If you try and fail, then all you have are meaningless noises or nonsensical marks on paper.
Hume has here a powerful critical tool. It seems
innocent enough, but Hume makes radical use of
it. The rule is a corollary to Hume’s Newtonian
analysis of phenomena. It is a result of the theory
of ideas.
The Association of Ideas
The results so far constitute the stage of analysis. What we find, on paying close attention to
the contents of the human mind, are impressions
and ideas, the latter in complete dependence on
the former. Hume now proceeds to the stage of
synthesis: What are the principles that bind these
elements together to produce the rich mental life
characteristic of humans? Like Newton, he finds
that the great variety of phenomena can be explained by a few principles, surprisingly simple in
nature. These are principles of association, and
they correspond in the science of human nature to
universal gravitation in the purely physical realm.
It is evident that there is a principle of connexion
between the different thoughts or ideas of the mind,
and that, in their appearance to the memory or
imagination, they introduce each other with a certain degree of method and regularity. . . . Were the
loosest and freest conversation to be transcribed,
there would immediately be observed something,
which connected it in all its transitions. Or where
this is wanting, the person, who broke the thread of
discourse, might still inform you, that there had secretly resolved in his mind a succession of thought,
which had gradually led him from the subject of
conversation. (HU, 101)
You should be able to test whether this observation
is correct by observing your own trains of thought
or noting how one topic follows another in a conversation you are party to.
If Hume is right here, the next question is,
What are these principles of association?
To me, there appear to be only three principles of
connexion among ideas, namely Resemblance, Contiguity in time or place, and Cause or Effect.
That these principles serve to connect ideas will
not, I believe, be much doubted. A picture naturally
to ourselves a just idea of the taste of a pine-apple,
without having actually tasted it. (T, I, 1, 1, p. 9)
This suggests that there is a relation of dependence
between them; Hume concludes that every simple
idea has some simple impression as a causal antecedent. Every simple idea, in fact, is a copy of a preceding impression.* What is the origin of all our
ideas? The impressions of experience. The rule is
this: no impression, no idea.
This is an apparently simple principle, but
Hume warns us that taking it seriously will have
far-reaching consequences. It is, in fact, a rule of
procedure that Hume makes devastating use of.
All ideas, especially abstract ones, are naturally
faint and obscure: The mind has but a slender hold
of them: They are apt to be confounded with other
resembling ideas; and when we have often employed any term, though without a distinct meaning, we are apt to imagine it has a determinate idea,
annexed to it. On the contrary, all impressions,
that is, all sensations, either outward or inward,
are strong and vivid: The limits between them are
more exactly determined: Nor is it easy to fall into
any error or mistake with regard to them. When
we entertain, therefore, any suspicion, that a philosophical term is employed without any meaning or
idea (as is but too frequent), we need but enquire,
from what impression is that supposed idea derived? And
if it be impossible to assign any, this will serve to
confirm our suspicion. (HU, 99)
Every meaningful term (word), Hume tells us,
is associated with an idea. Some terms, however,
have no clear idea connected with them. We get
used to them and think they mean something, but
we are deceived. Hume in fact thinks this happens
all too frequently! How can we discover whether
a term really means something? Try to trace the
associated idea back to an impression. If you can, it
is a meaningful word that expresses a real idea.
*Compare Hobbes, p. 406, and Locke, p. 417. Hume’s
theory of the origin of ideas is similar, but without Hobbes’
mechanistic explanation and without the assumption that
external objects are the cause of our impressions. Hume
considers both these claims merely “hypotheses.” The perceptions of the mind are our data; beyond them we may not
safely go.
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One more distinction will set the stage.
All the objects of human reason or enquiry may naturally be divided into two kinds, to wit, Relations
of Ideas, and Matters of Fact. Of the first kind are
the sciences of Geometry, Algebra, and Arithmetic;
and in short, every affirmation, which is either intuitively or demonstratively certain. That the square
of the hypothenuse is equal to the square of the two sides,
is a proposition, which expresses a relation between
these figures. That three times five is equal to the half of
thirty, expresses a relation between these numbers.
Propositions of this kind are discoverable by the
mere operation of thought, without dependence on
what is anywhere existent in the universe. Though
there never were a circle or triangle in nature, the
truths, demonstrated by Euclid, would forever
retain their certainty and evidence.
Matters of fact, which are the second objects
of human reason, are not ascertained in the same
manner; nor is our evidence of their truth, however
great, of a like nature with the foregoing. The contrary of every matter of fact is still possible; because
it can never imply a contradiction, and is conceived
by the mind with the same facility and distinctness,
as if ever so conformable to reality. That the sun will
not rise to-morrow is no less intelligible a proposition, and implies no more contradiction, than the
affirmation, that it will rise. We should in vain,
therefore, attempt to demonstrate its falsehood.
Were it demonstratively false, it would imply a
contradiction, and could never be distinctly conceived by the mind. (HU, 108)
The contrast drawn in these paragraphs is
an important one. Let’s be sure we understand
it. Suppose that yesterday you had uttered two
A: Two plus three is not five.
B: The sun will not rise tomorrow.
The sun did rise this morning.* Thus, both
statements are false. But what Hume draws our attention to is that they are false in different ways. A is
false simply because of the way in which the ideas
“two,” “plus,” “three,” “five,” and “equals” are related to each other. To put them together as A does
*We feel safe saying this because if the sun had not risen
this morning, you almost certainly would not be reading this.
leads our thoughts to the original [Resemblance]:
The mention of one apartment in a building naturally introduces an enquiry or discourse concerning
the others [Contiguity]: And if we think of a wound,
we can scarcely forbear reflecting on the pain which
follows it [Cause and Effect]. (HU, 101–102)
There is some question about whether this list
of three principles is complete; Hume thinks it
probably is and invites you to try to find more if
you think otherwise. The world of ideas, then, is
governed by the “gentle force” of association. He
likens it to “a kind of ATTRACTION, which in the
mental world will be found to have as extraordinary effects as in the natural, and to shew itself in as
many and as various forms” (T, I, 1, 4, pp. 12, 14).
It is important to note that this “gentle force”
operates entirely without our consent, will, or
even consciousness of it. It is not something in our
control, any more than we can control the force of
gravity. If Hume is right, it just happens that this is
how the mind works. He does not think it possible
to go on to explain why the mind works the way
it does; explanation has to stop somewhere, and,
like Newton, he does not “frame hypotheses.” But
these principles, he thinks, can be “deduced from
the phenomena.”
1. Using the quotation from Immanuel Kant as a cue,
explain the notion of enlightenment.
2. Contrast rationalism, materialism, and empiricism
and relate each to Newton’s rule about not framing
3. How does Hume explain the origin of our ideas?
(Distinguish complex from simple ideas.)
4. What principles govern transitions from one idea or
impression to another?
Causation: The Very Idea
We now have the fundamental principles of
Hume’s science of human nature: an analysis into
the elements of the mind (impressions and ideas),
the relation between them (dependence), and the
principles that explain how ideas interact (association). We are now ready for the exciting part:
What happens when this science is applied?
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We don’t usually think so. We talk confidently
of things beyond the reach of our senses and
memory—of what’s going on in the next room or
on the moon, of what happened long before we
were born, of a whole world of objects that exist
(we think) quite independent of our minds, and
many of us think it sensible to talk of God and the
soul. All this is common sense, and yet it goes far
beyond the narrow bounds of Hume’s data. What
can we make of this? Or rather, what can Hume
make of it? He considers some examples:
• A man believes that his friend is in France. Why?
Because he has received a letter from his friend.
• You find a watch on a desert island and conclude that some human being had been there
before you.
• You hear a voice in the dark and conclude there
is another person in the room.
In each of these cases, where someone claims
to know something not present in his perceptions,
you will find that a connection is being made by the
relation of cause and effect. In each case a present
impression (reading the letter, seeing the watch,
hearing the voice) is associated with an idea (of the
friend’s being in France, of a person’s dropping the
watch, of someone speaking). The way we get beliefs about matters of fact beyond the present testimony of our senses and memory is by relying on
our sense of causal relations. The letter is an effect of
our friend’s having sent it; the watch was caused to
be there on the beach by another person; and voices
are produced by human beings. Or so we believe. It
is causation that allows us to reach out beyond the
limits of present sensation and memories.
All reasonings concerning matter of fact seem to
be founded on the relation of Cause and Effect. By
means of that relation alone we can go beyond the
evidence of our memory and senses. (HU, 109)
This seems like progress, though it is hardly
very new. Descartes, you will recall, escapes solipsism by a causal argument for the existence of
God. But Hume now presses these investigations
in a novel direction. How, he asks, do we arrive at
the knowledge of cause and effect?
The first part of his answer to this question is
a purely negative point. We do not, and cannot,
is not just to make a false statement; it is to utter a
contradiction, to say something that cannot even be
clearly conceived. As Hume puts it, we can know
it is false “by the mere operation of thought.” We
do not have to make any experiments or look to
our experience. The opposite of A can in turn be
known to be true, no matter what is “anywhere existent in the universe.”
However, we can clearly conceive B even
though it turned out to be false. It is not false because the ideas in it are related the way they are;
given the way they are related, it might have been
true. We can clearly conceive what that would
have been like: You woke up to total and continuing darkness. Whether B is true or false depends
on the facts, on what actually happened in nature.
And to determine its truth or falsity you needed to
do more than just think about it. You needed to
consult your experience. The falsity of B, Hume
says, cannot be demonstrated. Reason alone will not
suffice to convince us of matters of fact; here only
experience will do.
And he suggests one further difference between
them: About relations of ideas like A we can be certain, but with respect to propositions stating matters of fact, our evidence is never great enough to
amount to certainty.*
We need to remind ourselves once again that
Hume is committed to sticking to the phenomena:
the perceptions of the mind, its impressions, and
its ideas. These are the data that need explaining
in a science of human nature. But now it is obvious
that a question forces itself on us. Is that all we can
know about?
*Hume is here suggesting a revolutionary understanding
of the kind of knowledge we have in mathematics. A contrast
with Plato will be instructive. For Plato (see pp. 152–153),
mathematics is the clearest case of knowledge we have. Not
only is it certain and enduring, but also it is also the best
avenue into acquaintance with absolute reality, for its objects
are independent of the world of sensory experience—eternal
and unchanging Forms. Hume, however, suggests that mathematics is certain not because it introduces us to such realities, but simply because of how it relates ideas to one another.
Mathematics has no objects. This suggestion undermines the
entire Platonic picture of reality. It is further developed in
the twentieth century by Ludwig Wittgenstein and the logical
positivists. See pp. 626–627 and 634–635.
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Hume is searching for what, if anything, makes this
a rational thing to believe. Because this time could
be very different from all those past times, the argument is invalid and does not give us a good reason
to believe that the second ball will move. Can we
patch up the argument?
Suppose we add a premise to the argument.
1a. The future will (in the relevant respect) be like
the past.
Now the argument looks valid. Propositions
1a, 1, and 2 do indeed entail proposition 3. If we
know that 1a is true, then, in the light of our experience summed up in 1 and 2, it is rational to
believe that the second billiard ball will move when
struck by the first one. We could call proposition
1a the principle of the uniformity of nature.
But how do you know that proposition 1a is
true? Think about that a minute. How do you know
that the future will be like the past? It is surely not
contradictory to suppose that the way events hang
together might suddenly change; putting the kettle
on the fire after today could produce ice. So 1a is
not true because of the relation of the ideas in it.*
Whether 1a is true or false must surely be a matter
of fact. So if we know it, we must know it on the
basis of experience. What experience? If we look
back, we can see that the futures we were (at various points) looking forward to always resembled
the pasts we were (at those points) recalling. This
suggests an argument to support 1a.
1b. I have experienced many pairs of events that
have been constantly conjoined in the past.
1c. Each time I found that similar pairs of events
were conjoined in the future. Therefore,
1a. The future will (in these respects) be like the
But it is clear that this argument is no better
than the first one; we are trying to justify our general principle 1a in exactly the same way as we tried
to justify the expectation that the struck billiard
ball would move (proposition 3). If it didn’t work
the first time, it surely won’t work now. The fact
*You should review the discussion of the distinction
between relations of ideas and matters of fact, pp. 445–446.
arrive at such knowledge independent of experience, or a priori: Our knowledge of causality is
not a matter of the relations of ideas.
Consider two events that are related as cause
and effect. To use a typical eighteenth-century example, think about two balls on a billiard table: the
cue ball strikes the eight ball, causing the eight ball
to move. Suppose we know all about the cue ball—
its weight, its direction, its momentum—but have
never had any experience whatsoever of one thing
striking another. Could we predict what would
happen when the two balls meet? Not at all. For
all we would know, the cue ball might simply stop,
reverse its direction, pop straight up in the air, go
straight through, or turn into a chicken. Our belief
that the effect will be a movement of the second ball
is completely dependent on our having observed
that sort of thing on prior occasions. Without that
experience, we would be at a total loss.
No object ever discovers, by the qualities which
appear to the senses, either the causes which produced it, or the effects which will arise from it; nor
can our reason, unassisted by experience, ever draw
any inference concerning real existence and matter
of fact. . . . causes and effects are discoverable, not by
reason, but by experience. (HU, 110)
My expectation that the second ball will move
when struck is based entirely on past experience.
I have seen that sort of thing happen before. This
seems entirely reasonable: I make a prediction on
the basis of past experience. But if that prediction
is reasonable, we ought to be able to set out the
reason for it. Reasons can be given in arguments.
Let us try to make the argument explicit.
1. I have seen one ball strike another many times.
2. Each time, the ball that was struck has moved.
3. The struck ball will move this time.
If we look at the matter this way, however, it is
easy to see that proposition 3 does not follow from
propositions 1 and 2. It seems possible that this time,
something else could happen. To be sure, none of
us believes that anything else will happen, but it
is precisely this belief, the belief that the first one
causes the second to move, that needs explanation.
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be able to discover any thing farther. He would not,
at first, by any reasoning, be able to reach the idea
of cause and effect; since the particular powers, by
which all natural operations are performed, never
appear to the senses; nor is it reasonable to conclude, merely because one event, in one instance
precedes another, that therefore the one is the
cause, the other the effect. Their conjunction may
be arbitrary and casual. . . .
Suppose again, that he has acquired more experience, and has lived so long in the world as to have
observed similar objects or events to be constantly
conjoined together; what is the consequence of this
experience? He immediately infers the existence
of one object from the appearance of the other.
(HU, 120–121)
This seems plausible. But what is the difference
between the first and the second supposition? The
only difference is that in the first case the man lacks
sufficient experience to notice which events are
“constantly conjoined” with each other. But what
difference does this difference make? What allows
him in the second case to make inferences and have
expectations, when he cannot do that in the first
case? If it is not a matter of reasoning, then there
must be
some other principle, which determines him to
form such a conclusion. This principle is CUSTOM
or HABIT. (HU, 121)
Note carefully what Hume is saying. Our
belief that events are related by cause and effect is
a completely nonrational belief. We have no good
reason to think this. We cannot help but believe
in causation, but we believe in it by a kind of instinct built into human nature: When we experience the constant conjunction of events, we
form a habit of expecting the second when we
observe the first, and we believe the first causes
the second.*
Custom, then, is the great guide of human life.
It is that principle alone, which renders our experience useful to us, and makes us expect, for the
future, a similar train of events with those which
*Compare this to al-Ghazālī theory about causation
(pp. 307–308).
that past futures resembled past pasts is simply no
good reason to think that future futures will resemble their relevant pasts.
Yet we all think that is so, don’t we? Our practical behavior surely testifies to that belief; we
simply have no hesitation in walking about on the
third floor of a building, believing that it will support us now just as it always has in the past. We all
believe in the uniformity of nature. But why? For
what reason?
Let us review. Hume is inquiring into the foundation of ideas about things that go beyond the
contents of our present consciousness. These ideas
all depend on relations of cause and effect: They
are effects caused in us by impressions of some
kind. But what is the foundation of these causal inferences? It can only be experience. But now we
see that neither experience nor the relations of idea can
supply a good reason for believing that my friend is in
France, for that belief rests on the assumption that
the future will resemble the past, which cannot
itself be justified by appealing to experience or to
the relations of ideas.
And so we have the first part of Hume’s answer
to the question about what justifies us in believing
in so many things independent of our present experience: not any reason!
We must be careful here. Hume is not advising
us to give up such beliefs; he thinks we could not,
even if we wanted to. “Nature will always maintain
her rights,” he says, “and prevail in the end over
any abstract reasoning whatsoever” (HU, 120). The
fact that these beliefs do not rest on any rational
foundation is an important result in his science of
human nature, and, as we’ll see, its philosophical
consequences are dramatic. But he acknowledges
that we cannot really do without these beliefs. Our
survival depends on them.
If we allow that these beliefs about the world
are not rationally based, the next obvious question
is this: What is their foundation? Hume suggests a
thought experiment.
Suppose a person, though endowed with the strongest faculties of reason and reflection, to be brought
on a sudden into this world; he would, indeed, immediately observe a continual succession of objects,
and one event following another; but he would not
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between event A and event B, the more probable
we think it that a new experience of A will be followed by B. Again, note that for Hume this is not
the result of a rational calculation. We do not decide
to believe with a particular degree of assurance.
It just happens. That is how we are made.*
This might seem unsatisfactory, for the idea of
constant conjunction does not seem to exhaust the
notion of causality. When we say that X causes Y,
we don’t just mean that whenever X occurs Y also
occurs. We mean that if X occurs, Y must occur,
that X produces Y, that X has a certain power to bring
Y into being. In short, we think that in some sense
the connection between X and Y is a necessary
connection. This is part of what we mean by the
idea of a cause. We could express this idea in a
Hume now owes us an account of this latter aspect
of the idea.
How can he proceed? The idea of cause is one
of those metaphysical ideas we are all familiar with,
but whose exact meaning is obscure. Hume has already given us a rule to deal with these cases: Try
to trace the idea back to an impression. What happens if we try to do that?
Think again about the billiard balls on the table.
Try to describe with great care your exact experience when seeing the one strike the other. Isn’t
it your impression that the cue ball moves across
the table, it touches the eight ball, and the eight
ball moves? Is there anything else you observe?
In particular, do you observe the force that makes
the second ball move? Do you observe the necessary
connection between the two events? Hume is convinced that you do not.
have appeared in the past. Without the influence
of custom, we should be entirely ignorant of every
matter of fact, beyond what is immediately present
to the memory and senses. (HU, 122)
Hume is here turning upside down the major
theme of nearly all philosophy before him. Almost
everyone in the philosophical tradition has agreed
that a person has a right to believe something only
if a good reason can be given for it. This goes back
at least to Plato.* The major arguments among the
philosophers concern what can (and what cannot)
be adequately supported by reason. This commitment to the rationality of belief is most prominent,
of course, in a rationalist such as Descartes, who
determines to doubt everything that cannot be
certified by the “light of reason.” The skeptics, on
these same grounds, argue that virtually no belief
in matters of fact can be known because virtually
nothing can be shown to be reasonable. Hume
seems to agree that virtually no belief in matters of fact can be shown to be reasonable; is he,
then, a skeptic? We return to this question later in
this chapter.
For now, let us note his conclusion that almost
none of our most important beliefs (all of which
depend on the relation between cause and effect)
can be shown to be rational. We hold them simply
out of habit. Our tendency to form beliefs about
the external world is just a fact about us; this is the
way human nature works. Hume does not try to
explain why human nature functions this way—it
just does. We should not frame hypotheses!
There is a corollary, which Hume is quick to
draw. Sometimes a certain event is always conjoined with another event. But in other cases, one
event follows another only in some or most cases.
Water always boils when put on a hot fire, but it
only sometimes rains when it is cloudy. These facts
are the foundation of probabilistic expectations.
Our degree of belief corresponds to the degree of
connection that our experience reveals between
the two events. The more constant the conjunction
*Review Plato’s distinction of knowledge from opinion in terms of the former being “backed up by reasons”
(pp. 150–151).
*A qualification needs to be made here. While our
degree of confidence in our beliefs is usually governed by this
principle, there are exceptions. We can be misled by thinking that certain ideas have meaning when they do not. Or
we can generalize too soon on the basis of limited information. These mistakes lead to what Hume calls “superstition.”
Most superstitions are erroneous beliefs about causes and
effects. Think about the bad luck supposedly associated with
breaking a mirror or walking under a ladder.
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This puzzle, Hume thinks, can be solved.
To solve it, we have to go back to the fact that
exposure to constant conjunctions builds up an
associationistic habit of expecting one event on the
appearance of the other. This habit is the key to
understanding the full concept of a cause.
After a repetition of similar instances, the mind is
carried by habit, upon the appearance of one event,
to expect its usual attendant, and to believe that it
will exist. This connexion, therefore, which we feel
in the mind, this customary transition of the imagination from one object to its usual attendant, is the
sentiment or impression, from which we form the
idea of power or necessary connexion. (HU, 145)
As we have seen, there are two things that go
into the concept of a cause. One component is a
constant conjunction of events. Of that we have
experience, and on that basis Hume offers the following definition of a cause:
an object, followed by another, and where all the
objects, similar to the first, are followed by objects
similar to the second. (HU, 146)
Notice that this is a reduced, cautious definition of
“cause.” It is not a definition of the full notion of
cause, which includes the idea of a necessary connection between events. We cannot, Hume says,
“point out that circumstance in the cause, which
gives it a connexion with its effect. We have no
idea of this connection” (HU, 146).
But we do experience something relevant
to our belief in necessary connection. We cannot
help but feel that there is a connection. It is on the
basis of this kind of subjective experience that
we project a necessary connection into the relation
between objective events. And Hume gives us a
second definition of cause:
an object followed by another, and whose appearance always conveys the thought to that other.
(HU, 146)
Hume has done two things. (1) He has provided
an account of the basis on which we have the idea
of cause at all—the observed constant conjunctions between kinds of events. (2) He has given an
explanation of why we attribute a necessary connection to those pairs of events—even though such
We are never able, in a single instance, to discover
any power or necessary connexion; any quality
which binds the effect to the cause, and renders the
one an infallible consequence of the other. We only
find, that the one does actually, in fact, follow the
other. . . . Consequently, there is not, in any single,
particular instance of cause and effect, any thing
which can suggest the idea of power or necessary
connexion. (HU, 136)
Mental phenomena are no different. If you will
to move your hand, your hand moves. If you try
to picture your best friend’s face, you can do it.
But no matter how closely you inspect these operations, all you can observe is one thing being followed by another. You never get an impression of
the connection between them. All relations of cause
and effect must be learned from experience; and
experience can show us only “the frequent CONJUNCTION of objects, without being ever able
to comprehend any thing like CONNEXION between them” (HU, 141).
Where then do we get this second part of our
idea of cause? Is it one of those ideas that is simply
meaningless? Should we discard it or try to do
without it? That seems hardly possible. Yet a close
inspection of all the data seems to confirm Hume’s
Upon the whole, there appears not, throughout
all nature, any one instance of connexion, which is
conceivable by us. All events seem entirely loose
and separate. One event follows another; but we
can never observe any tie between them. They
seem conjoined, but never connected. And as we can
have no idea of any thing, which never appeared to
our outward sense or inward sentiment, the necessary conclusion seems to be, that we have no idea of
connexion or power at all, and that these words are
absolutely without any meaning, when employed
either in philosophical reasonings, or common life.
(HU, 144)
“All events seem entirely loose and separate.” And
the conclusion seems to be that we have no idea of
cause at all—because there is no corresponding
impression of necessary connections. But then it is
really puzzling why this idea should be so natural,
so pervasive, and so useful. It is an idea we all have,
and one we can hardly do without.
The Disappearing Self 451
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The Brahmanical philosophers in India identify the
self with ātman. Avicenna imagines that his Flying
Man could recognize the existence of his self.*
In modern times, Descartes follows Plato’s lead,
maintaining that the soul or mind is an immaterial
and immortal substance, Locke posits spiritual substances, and Berkeley argues that spirits and their
ideas make up the whole of reality.
Hume can hardly avoid dealing with this question, since he claims to be constructing a science
of human nature. The first thing we need to do,
to the extent possible, is to clarify the meaning
of the central term. What Plato called “soul” and
Descartes the “mind,” Hume names the “self.” A
self is supposedly a substance or thing, simple
(not composed of parts), and invariably the same
through time. It is the “home” for all our mental
states and activities, the “place” where these characteristics are “located.” (The terms in quotes are
used metaphorically.) Your self is what is supposed
to account for the fact that you are one and the
same person today as you were at the age of four,
even though nearly all your characteristics have
changed over the years. You are larger, stronger,
and smarter; you have different hopes and fears,
different thoughts and memories; your interests
and activities are remarkably different. Yet you are
the same self. Or so the story goes.†
It is clear what Hume will ask here. Remember
his rule: If a term is in any way obscure, or a subject of much controversy, try to trace it back to an
From what impression cou’d this idea be derived?
This question ’tis impossible to answer without a
manifest contradiction and absurdity; and yet ’tis
a question, which must necessarily be answer’d, if
we wou’d have the idea of self pass for clear and
intelligible. It must be some one impression, that
gives rise to every real idea. But self or person is
necessary connections are never experienced. The
full concept of a cause is a kind of fiction.* Necessary connections do not appear anywhere in
our experience, but we cannot help applying that
notion to observed events.
Remembering that we rely on cause and effect
for all our inferences to realities beyond present
consciousness, we now see that all such beliefs are
simply based on habit. We have no reason for belief
in an external world, in the reality of other persons, or even in past events. If knowledge is based
on reason, as the philosophical tradition has held,
there is precious little we can claim to know!
1. Contrast relations of ideas with matters of fact.
Give some examples of your own.
2. What is Hume’s argument for the conclusion that
causes and effects are discoverable not by reason
but by experience?
3. If our beliefs about causation are dependent on
experience, what experiences are of the relevant
4. How does Hume explain our judgments of
5. Granted that the idea of necessary connection is an
important part of our idea of a cause, how does
Hume account for that?
6. What part of our idea of causation is a fiction,
according to Hume? What part is not?
The Disappearing Self
Most philosophers in the Western tradition, along
with many in the Indian tradition, have taken human
beings to have an enduring self that is somehow distinct from the body. Plato argues that a person is
really a soul. Aristotle holds (with qualifications)
that the soul is a functional aspect of a living body.
*Hume does not apply the term “fiction” to his account
of causality; but he does use it when talking of (1) the identity of objects through time, (2) the existence of objects
independent of experience, and (3) personal identity in a
continuing self. Since the pattern of analysis is similar in
all these cases, we think it is justified to use the term here.
We are indebted to Matthew McKeon for additional clarity
on this topic.
*For Plato’s views, see p. pp. 168–170. For Aristotle’s,
see pp. 203–206. On ātman, see pp. 36–37. For Avicenna’s
views, see pp. 304–305.
†It would be helpful at this point to review what Locke
says about personal identity (pp. 419–420). Note that
he argues that my identity cannot consist in sameness of soul
or self, though he doesn’t find those terms meaningless.
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or shade, love or hatred, pain or pleasure. I never
can catch myself at any time without a perception,
and never can observe any thing but the perception.
When my perceptions are remov’d for any time, as
by a sound sleep; so long am I insensible of myself,
and may truly be said not to exist. And were all my
perceptions remov’d by death, and cou’d I neither
think, nor feel, nor see, nor love, nor hate after
the dissolution of my body, I shou’d be entirely annihilated, nor do I conceive what is farther requisite
to make me a perfect non-entity. If any one upon
serious and unprejudic’d reflexion, thinks he has
a different notion of himself, I must confess I can
reason no longer with him. All I can allow him is,
that he may be in the right as well as I, and that we
are essentially different in this particular. (T, I, 4,
6, p. 165)
Again, Hume tries to pay close attention to the
phenomena and tries not to frame hypotheses. If we
look inside ourselves, do we find an impression of
something simple, unchanging, and continuing? He
confesses that he can find no such impression, and
his suggestion that maybe you can, that maybe you
are “essentially different” in this regard, is surely
ironic. His claim is that none of us ever finds more
in ourselves than fleeting perceptions—ideas, sensations, feelings, and emotions.
“Since our inner experiences consist of
reproductions and combinations of sensory
impressions, the concept of a soul without a
body seems to me to be empty and devoid of
Albert Einstein (1879–1955)
So we have no reason to suppose that we are
selves, or minds, or souls, if we understand those
terms to refer to some simple substance that underlies all our particular perceptions. But what,
then, are we?
I may venture to affirm of the rest of mankind, that
they are nothing but a bundle or collection of different perceptions, which succeed each other with an
inconceivable rapidity, and are in a perpetual flux
and movement. . . . The mind is a kind of theatre,
not any one impression, but that to which our several impressions and ideas are suppos’d to have a
reference. If any impression gives rise to the idea of
self, that impression must continue invariably the
same, thro’ the whole course of our lives; since self
is suppos’d to exist after that manner. But there is
no impression constant and invariable. (T, I, 4, 6,
p. 164)
Let us be clear about the argument here. The
term “self” is supposed to represent an idea of
something that continues unchanged throughout
a person’s life. Since the idea is supposed to be a
simple one, there must be a simple impression that
is its “double.” But there is no such impression,
Hume claims, “constant and invariable” through
life. It follows, according to Hume’s rule, that we
have no such idea! The term is one of those meaningless noises that we wrongly suppose to mean something, when it really doesn’t.
This is a most radical way of undermining belief
in the soul or self. Some philosophers claim to
have such an idea and to be able to prove the self
really exists. Others claim to be able to prove that
it doesn’t exist. But Hume undercuts both sides;
they are just arguing about words, he holds, because neither side really knows what it is talking
about. Literally! There simply is no such idea as the
(supposed) idea of the self, so it doesn’t make sense
to affirm it or to deny it.
This claim, of course, rests on the theory of
ideas. It is only as strong as that theory is good. Is
that a good theory? This is an important question;
in later chapters, we meet other philosophers who
investigate this question.* But for now, let us explore in a bit more depth why Hume thinks there is
no impression that corresponds to the (supposed)
idea of the self. In a much-quoted passage, Hume
For my part, when I enter most intimately into
what I call myself, I always stumble on some particular perception or other, of heat or cold, light
*Kant, for instance, denies a key premise of the theory
of ideas: that all our ideas (Kant calls them “concepts”) arise
from impressions. Some of our concepts, Kant claims, do
not arise out of experience, though they may apply to experience. See pp. 473–474.
Rescuing Human Freedom 453
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thinking is to frame a hypothesis, to go beyond the
evidence available.7
If this criticism is correct, it
undermines Descartes’ dualistic metaphysics; we
cannot know that the mind is a substance distinct
from the body because we cannot know it is a substance at all! All we have is acquaintance with that
bundle of perceptions.
Rescuing Human Freedom
A science of human nature must also address
whether human actions are in some sense free.
The mechanistic physical theories of Galileo and
Newton give this question new urgency. As long as
the entire world is conceived in Aristotelian terms,
where a key mode of explanation is teleological,*
the question of freedom is not pressing. If everything
acts for the sake of some end, pursuing its good
in whatever way its nature allows, human actions
would fit the general pattern neatly. Humans have
more alternatives available than do petunias and
snails, and they make choices among the available
goods. But the pattern of explanation would be
common to all things.
Early modern science, however, has banished
explanation in terms of ends or goals; explanation
by prior causes is “in.” The model of the universe
is mechanical; the world is compared to a gigantic
clock. Stones do not fall in order to reach a goal, and
oak trees do not grow because of a striving to realize
the potentiality in them. Everything happens as it
must happen, according to laws that make no reference to any end, goal, or good.
Are human actions like this, as strictly determined by law and circumstance as the fall of the
stone? The view that human actions constitute
no exception to the universal rule of causal law is
known as determinism. The successes of modern
science give it plausibility. But it seems to clash
with a deeply held conviction that sometimes we
are free to choose, will, and act.
where several perceptions successively make their
appearance; pass, re-pass, glide away, and mingle in
an infinite variety of postures and situations. There
is properly no simplicity in it at any one time, nor
identity in different; whatever natural propensity we
may have to imagine that simplicity and identity.
The comparison of the theatre must not mislead
us. They are the successive perceptions only, that
constitute the mind; nor have we the most distant
notion of the place, where these scenes are represented, or of the materials, of which it is compos’d.
(T, I, 4, 6, p. 165)
Like the idea of cause, the idea of the self is a
fiction. As selves or minds, we are nothing but a
“bundle” of perceptions. Anything further is sheer,
unsupported hypothesis. We have not only no
reason to believe in a world of “external” things
independent of our minds, but also no reason to
believe in mind as a thing.*
In thinking of ourselves, Hume suggests, the
analogy of a theater is appropriate. In this theater,
an amazingly intricate play is being performed. The
players are just all those varied perceptions that
succeed each other, as Hume says, with “inconceivable rapidity.” But if we are to understand the
analogy correctly, we must think away the walls of
the theater, think away the stage, think away the
seats and even the audience. What is left is just the
performance of the play. Such a performance each
of us is.
How does this bundle theory of the self bear
on Descartes’ cogito, “I think, therefore I am”? Descartes takes this as something each of us knows with
certainty. And in answer to the question, “What,
then, am I?” he says, “I am a thing (a substance)
that thinks.” Hume is in effect saying that Descartes is going beyond what the phenomena reveal.
A twentieth-century Humean, Bertrand Russell,
puts it this way: The most that Descartes is entitled
to claim is that there is thinking going on. To claim
that there is a mind or self—a thing—doing the
*Compare the Buddhist doctrine of anātman or nonself (pp. 41–45). The psychologist and philosopher Alison
Gopnik speculates that Hume might have learned about
Buddhist philosophy through the Jesuit missionary Charles
Francois Dolu while both were living in La Flèche, France,
in the 1730s.
*An explanation is teleological if it makes essential reference to the realization of a goal or end state. Aristotle’s
discussion of “final causes” provides a good case study (see
pp. 195–197).
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all must admit that there are. He gives some examples (HU, 150, 151):
• Motives are regularly conjoined to actions:
Greed regularly leads to stealing, ambition to
the quest for power.
• If a foreigner acts in unexpected ways, there is
always a cause—some condition (education,
perhaps) that regularly produces this behavior.
• Where we are surprised by someone’s action,
a careful examination always turns up some
unknown condition that allows it to be fit again
into a regular pattern.
If all that we can possibly mean by “caused” is
that events are regularly connected, we should all
agree that human behavior is caused. Why do some
of us resist this conclusion? Because, Hume says,
men still entertain a strong propensity to believe,
that they penetrate farther into the powers of
nature, and perceive something like a necessary
connexion between the cause and the effect. When
again they turn their reflections towards the operations of their own minds, and feel no such connexion of the motive and the action; they are thence
apt to suppose, that there is a difference between
the effects, which result from material force, and
those which arise from thought and intelligence.
(HU, 156, 157)
But this is just a confusion! Causality on the side of
the objects observed is just regularity, and on the
side of the observer it is the generation of a habit
based on regularities. In neither case, material or
intelligent, is there any necessity observed. Human
actions are “caused” in exactly the same sense as
events in the material world.
What then of freedom or liberty?
It will not require many words to prove, that all
mankind have ever agreed in the doctrine of liberty
as well as in that of necessity, and that the whole
dispute, in this respect also, has been hitherto
merely verbal. For what is meant by liberty, when
applied to voluntary actions? We cannot surely
mean, that actions have so little connexion with
motives, inclinations, and circumstances, that one
does not follow with a certain degree of uniformity
from the other, and that one affords no inference
by which we can conclude the existence of the
other. . . . By liberty, then, we can only mean a
Descartes shows us one way to deal with this
problem: Make an exception for human beings!
Mechanical principles might govern material
bodies, but they can have no leverage on a nonmaterial mind. The will, Descartes says, is completely free. And by “free” he means “not governed
by causal laws.”
But Hume cannot take this way, for he is convinced we have no idea of a substantial self, so we
can have no reason to think such a nonmaterial
mind or soul exists. Hume’s solution to this puzzle
is quite different from Descartes’, and it is justly
famous. Its basic pattern is defended by numerous
philosophers (but not all) even today.
He begins by asserting that “all mankind” is of
the same opinion about this matter. Any controversy is simply due to “ambiguous expressions”
used to frame the problem. In other words, if we
can get our terms straight, we should be able to
settle the matter to everyone’s satisfaction. What
we need is a set of definitions for what Hume calls
“necessity” on the one hand and “liberty” on the
I hope, therefore, to make it appear, that all men
have ever agreed in the doctrine both of necessity
and of liberty, according to any reasonable sense,
which can be put on these terms; and that the
whole controversy has hitherto turned merely upon
words. (HU, 149)
We already know what Hume says about necessity. The idea of necessity is part of our idea of
a cause but is a kind of fiction. It arises not from
impressions, but from that habit our minds develop when confronted with regular conjunctions
between events. All we ever observe, when we believe that one event causes another, is the constant
conjunction of events of the first kind with events
of the second.
Are human actions caused? If we understand
this in what Hume thinks is the only possible way,
we are simply asking whether there are regularities
detectable in human behavior.* And he thinks we
*Look again at Hume’s two definitions of “cause” on
p. 450.
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1. What does Hume fail to find when—as he says—he
enters most intimately into what he calls himself?
2. What conclusions does Hume draw about the
nature of a “self”?
3. Explain how Hume thinks the necessity of actions (i.e.,
that they have causes) is compatible with the fact of
liberty in actions (i.e., that sometimes we act freely).
Is It Reasonable to Believe in God?
After doubting everything doubtable, Descartes
finds himself locked into solipsism—unless he
can demonstrate that he is not the only thing that
exists. The way he does this, you recall, is to try
to demonstrate the existence of God. He looks,
in other words, for a good reason to believe that
something other than his own mind exists. If he can
prove that God exists, he knows he is not alone;
and, God being what God is, he will have good
reason to trust at least what is clear and distinct
about other things as well. Thus everything hangs,
for Descartes, on whether it is reasonable to believe that there is a God.*
What does Hume say about this quest to show
that belief in God is more reasonable than disbelief?
We review briefly two of the arguments Descartes
presents, together with a Humean response to
each, and then we look at a rather different argument that was proving very popular in the atmosphere after Newton.
Descartes first argues that we can infer God’s
existence from the mere fact that we have an idea
of an infinite and perfect being. Claiming that
he himself cannot be the source of such an idea,
Descartes concludes that God himself must be its
cause.† Hume counters that
*Earlier thinkers, too, from Aristotle on, think they
can give good reasons for concluding that some ultimate perfection exists and is in one way or another responsible for all
other things. Review the proofs given by Augustine (p. 269),
Anselm (pp. 312–314), Avicenna (p. 323), and Aquinas
(pp. 302–304). The arguments of Descartes are in Meditations
III and V. †See Descartes’ argument in Meditations III,
pp. 378–379.
power of acting or not acting, according to the determinations of the will; that is, if we choose to remain at
rest, we may; if we choose to move, we also may.
Now this hypothetical liberty is universally allowed
to belong to everyone, who is not a prisoner and in
chains. (HU, 158–159)
Perhaps the most accessible way to understand
Hume’s point is to think of cases where a person is
said to be unfree. Hume’s example is that of a man in
chains. Isn’t such a man unfree precisely because he
cannot do what he wants to do? Even if he yearns to
walk away, wills to walk away, tries to walk away, he
will be unable to walk away. He is unfree because his
actions are constrained—against his will, as we say.
Suppose we remove his chains. Then he is free,
at liberty to do what he wants. And isn’t this the
very essence of freedom: to be able to do whatever
it is that you want or choose to do? We could put
this more formally in the following way:
A person P is free when the following condition is
satisfied: If P chooses to do action A, then P does A.
If this condition were not satisfied (if P should
choose to do A but be unable to do it), then P would
not be at liberty with respect to A.
Hume wants to reconcile our belief in causality with our belief in human freedom. We do not
have to choose between them. We can have both
modern science and human freedom. Newtonian
science and freedom would clash only if freedom
entailed exemption from causality. But causes are
simply regularities; and freedom is not an absence
of regularity, but the “hypothetical” power to do
something if we choose to do it. It is, in fact, a certain kind of regularity. It is the regularity of having
the actions we choose to do follow regularly upon
our choosing to do them.
There is no reason, then, in human liberty, to
deny that a science of human nature—a causal science of a Newtonian kind—is possible. And Newtonian, mechanistic science is no reason to deny or
doubt human freedom or to postulate a Cartesian
mind that eludes the basic laws of the universe.
Hume’s compatibilism, as it is sometimes called,
is an important part of a kind of naturalism, a
view that takes the human being to be a natural
fact, without remainder.
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Look round the world: Contemplate the whole
and every part of it: You will find it to be nothing
but one great machine, subdivided into an infinite
number of lesser machines, which again admit of
subdivisions to a degree beyond what human senses
and faculties can trace and explain. All these various machines, and even their most minute parts,
are adjusted to each other with an accuracy which
ravishes into admiration all men who have ever
contemplated them. The curious adapting of means
to ends, throughout all nature, resembles exactly,
though it much exceeds, the productions of human
contrivance; of human design, thought, wisdom,
and intelligence. Since therefore the effects resemble each other, we are led to infer, by all the
rules of analogy, that the causes also resemble, and
that the Author of Nature is somewhat similar to
the mind of man, though possessed of much larger
faculties, proportioned to the grandeur of the work
which he has executed. By this argument a posteriori,
and by this argument alone, do we prove at once
the existence of a Deity and his similarity to human
mind and intelligence. (D, II, 45)
Let us note several points about this argument.
It is an argument, Hume says, a posteriori; that
is, it depends in an essential way on experience.
Our experience of the world as an ordered and
harmonious whole provides one crucial premise;
our experience of how machines come into being
provides another. Note also that it is an argument
by analogy. Its structure looks like this (M = a machine; I = intelligence; W = the world):
1. M is the effect of I.
2. W is like M. Therefore,
3. W is the effect of something like I.
Finally, you should recognize that this, like Descartes’ first two arguments, is a causal argument.
Both the first premise and the conclusion deal with
causal relations.
Hume says many interesting things about this
argument, partly through his spokesmen in the dialogue. Here we are brief, simply listing a number
of the points he makes.
1. No argument from experience ever can establish a certainty. The most that experience can
yield is probability (since experience is always limited and cannot testify to what is beyond its limits).
the idea of God, as meaning an infinitely intelligent,
wise, and good Being, arises from reflecting on the
operations of our own mind, and augmenting, without limit, those qualities of goodness and wisdom.
(HU, 97–98)
By extrapolating from our internal impressions
of intelligence, goodness, and wisdom, we can get
the idea of a being that is perfectly intelligent and
completely good. And this is the idea of God.* This
undercuts Descartes’ argument.
Descartes’ third argument is, roughly, that because the idea of God as nonexistent is as absurd
as the idea of a mountain without a valley or a triangle with more than three sides, the mere fact that
we have the idea of God means that God exists.†
But this, Hume objects, is to illegitimately infer a
matter of fact from a mere relation of ideas. Perhaps
thinking of God entails thinking that he exists; but
that concerns only how those ideas are related to
each other, not whether God in fact exists. That is
a question that can only be settled by reference to
The most popular argument for God during
the Enlightenment, among common folk and intellectuals alike, does begin from experience. It can
be called the argument from design.‡ Newton
set the idea that the universe is a magnificently ordered arrangement on a firm scientific footing. The
image of a great machine, or clockwork, dominates eighteenth-century thought about the nature
of the world. And it suggests a powerful analogy.
Just as machines are the effects of intelligent design
and workmanship, so the universe is the work of a
master craftsman, supremely intelligent and wonderfully skilled. Machines don’t just happen and
neither does the world.
In a set of dialogues that Hume did not venture
to publish during his lifetime, one of the participants sets out this argument:
*Descartes foresees this line of argument and tries to
block it. Go back to Meditation III, p. 378–379, to see if you
think he is successful.
†See Descartes’ argument in Meditation V (p. 389) and
our discussion on pp. 391–392.
‡Compare the fifth way of Thomas Aquinas,
pp. 323–324. See also Berkeley, pp. 434–435.
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in certain respects and differences in others. How
do we know which are the similarities in this case
and which are the differences? Unless we have
some principled way to make this distinction, any
one of these conclusions is as justified as the one
theists wish to draw.
4. Finally, we have to ask what we can learn
from a single case. Here Hume applies his analysis
of the idea of causality to the case of the cause of
the world.
It is only when two species of objects are found to
be constantly conjoined, that we can infer the one
from the other; and were an effect presented, which
was entirely singular, and could not be comprehended under any known species, I do not see, that
we could form any conjecture or inference at all
concerning its cause. (HU, 198)
There is one respect in which this universe is
entirely unlike the clocks and automobiles and
iPhones of our experience: It is, in our experience, “entirely singular.” We can infer that the
cause of a new computer is some intelligent human
because we have had past experience of the constant conjunction of computers and intelligent
designers. We experience both the effects and the
causes. To apply this kind of analogical reasoning
to the universe, we would need past experience of
the making of worlds; and in each instance there
would have to have been a conjoined experience of
an intelligent being. On the basis of such a constant
conjunction, we could infer justly that this world,
too, is the effect of intelligence. But since the universe is, in our experience, “entirely singular,” we
can make no such inference. These, and more, are
the difficulties Hume finds in the design argument.
“I myself believe that the evidence for God
lies primarily in inner personal experiences.”
William James (1842–1910)
According to Hume’s principles, any causal
argument for God is subject to this last criticism.
But now we are in a position to see that our situation is much worse than we ever imagined.
So even if the argument is a good one (of its kind),
it does not give us more than a probability that the
“Author of Nature” is analogous to a human designer.
2. There is a sound principle to be observed in
all causal arguments: that “the cause must be proportioned to the effect.”
A body of ten ounces raised in any scale may serve
as a proof, that the counterbalancing weight exceeds
ten ounces; but can never afford a reason that it exceeds a hundred. . . . If the cause be known only by
the effect, we never ought to ascribe to it any qualities, beyond what are precisely requisite to produce
the effect. (HU, 190)
If we look around at the world, can we say that
it is perfectly good? That is hard to believe. If we
think of this proof as an attempt to demonstrate the
existence of God as he is traditionally conceived—
infinite in wisdom and goodness—it surely falls
short. For the proportion of goodness we are
justified in ascribing to the cause (God) cannot far
exceed the proportion of goodness (in the world)
that needs to be explained.
3. The analogy is supposed to exist between
the productions of intelligent human beings and
the world as an effect of a supremely intelligent designer. But a number of consequences follow if we
take the analogy seriously.
• Many people cooperate to make a machine;
by analogy, the world may have been created
through the cooperation of many gods.
• Wicked and mischievous people may create
technological marvels; by analogy, the creator(s)
of the world may be wicked and mischievous.
• Machines are made by mortals; by analogy, may
not the gods be mortal?
• The best clocks are a result of a long history of
slow improvements; by analogy,
Many worlds might have been botched and bungled,
throughout an eternity, ere this system was struck
out; much labor lost; many fruitless trials made; and
a slow but continued improvement carried on during
infinite ages in the art of world-making. (D, 36)
The point here is not that any of these possibilities is
likely but that analogies always have resemblances
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instructor. To be a philosophical skeptic is, in a man
of letters, the first and most essential step towards
being a sound, believing Christian. (D, XII, 130)
What can we make of this? Is Hume serious
here? Or, more important, is this a serious possibility, this combination of religious faith and philosophical skepticism? What would this be like?*
1. How, according to Hume, does the idea of God
originate? Compare Hume’s view to Descartes’
2. How does Hume use the notion of relations of
ideas to block the ontological arguments of Anselm
(pp. 312–314) and Descartes (Meditation V)?
3. State clearly the argument from design and sketch
several of Hume’s criticisms.
Understanding Morality
We often find ourselves making judgments like
this: “That was a bad thing Jones did,” “Smith is a
good person,” “Telling the truth is the right thing
to do,” and “Justice is a virtue.” You see twenty
dollars in an unattended backpack in the library;
no one is around, and you could pick it up; you
say to yourself, “That would be wrong,” and walk
away. Such moral judgments are very important to
us, both as evaluations of the actions of others and
as guides to our own behavior. They are no less
important to society. A science of human nature
ought to have something to say about this feature
of human life, so Hume tries to understand our
propensity to make judgments of this kind. As we
might anticipate by now, he puts his question this
way: Are these judgments founded in some way on
reason, or do they have some other origin?
Reason Is Not a Motivator
Nothing is more usual in philosophy, and even in
common life, than to talk of the combat of passion and reason, to give the preference to reason,
These reflections not only undercut causal arguments for God’s existence, but also undermine
causal arguments for the existence of anything at
all beyond our own impressions!* For causal judgments are always founded on the constant conjunction of pairs of events within our experience. To
judge that some extramental object is the cause of
a perception, we would need to be able to observe
a constant conjunction of that perception with its
extramental cause. But to do that we would need
to jump out of our own skins, observe the perception from outside, and compare it with the external
thing correlated with it. And that we cannot do.
If Hume is right about the origin of the concept
of causality within experience, we could never have
the evidence required to validate any claim about
external objects. All we can do is relate perceptions to perceptions. And if Descartes is right that
without good reason to believe in God we are caught
within the web of our own ideas, then solipsism
seems (rationally) inescapable†—a dismal and melancholy conclusion.
After reviewing these attempts to make belief
in God reasonable, it seems that we have so far
not found good reason to believe in God. Now we
must add that neither have we found good reason
to believe in the existence of a material world independent of our perceptions. We can think of this
as a radical consequence of the representational
theory (p. 372). Hume shows us that if we begin
from ideas in the mind, there is no way to build
that bridge to the world beyond.
This is not, however, Hume’s last word on the
subject of religion. In a passage that has puzzled
many commentators, one of Hume’s characters
goes on to say,
A person, seasoned with a just sense of the imperfections of natural reason, will fly to revealed
truth with the greatest avidity: While the haughty
dogmatist, persuaded that he can erect a complete
system of theology by the mere help of philosophy,
disdains any further aid and rejects this adventitious
*Here we see how—accepting the starting points of
Locke and Berkeley—Hume presses their empiricist principles to radical and (apparently) skeptical conclusions.
†Solipsism is explained on p. 382.
*Fideism, as this view is sometimes called, is explored
in the work of Søren Kierkegaard. See “The Religious,” in
Chapter 22.
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Perhaps to your second question, why he desires
health, he may also reply that it is necessary for the exercise
of his calling. If you ask why he is anxious on that head,
he will answer, because he desires to get money. If you
demand why? It is the instrument of pleasure, says he.
And beyond this it is an absurdity to ask for a reason.
It is impossible there can be a progress in infinitum;
and that one thing can always be a reason why another
is desired. Something must be desirable on its own
account, and because of its immediate accord or agreement with human sentiment and affection. (PM, 163)
Here we have reasoning about matters of fact;
it is a fact that exercise is conducive to health, that
health is required to pursue a profession successfully, and so on. But mere knowledge of these
matters of fact will not motivate action unless one
cares about the end to which they lead. And this
caring is not itself a matter of reason. It is a matter
of sentiment or passion. Hume draws this conclusion:
It appears evident that the ultimate ends of human
actions can never, in any case, be accounted for by
reason, but recommend themselves entirely to the sentiments and affections of mankind, without any dependence on the intellectual faculties. (PM, 162–163)
So reason alone can never motivate us to action.
But Hume goes even further; he claims that reason
can never oppose passion; only a passion can oppose
another passion. For example, as you contemplate
a roller coaster ride, fear fights with the desire for
thrills. Likewise, one rational proposition can be
opposed to another when they are contradictory.
But for reason to oppose passion, it would have to
be a motivator in itself, and Hume argues that it is
not. Reason, we might say, is inert.
We speak not strictly and philosophically when we
talk of the combat of passion and of reason. Reason
is, and ought only to be the slave of the passions,
and can never pretend to any other office than to
serve and obey them. (T, II, 3, 3, 266)
Reason can instruct us how to satisfy our desires, but it cannot tell us what desires to have.*
*You might think there is an obvious exception: Suppose
you had a desire to smoke cigarettes. Couldn’t reason tell
you that it would be better for you if you didn’t have that
desire? And wouldn’t this be a case of reason opposing
a desire you have? What would Hume say?
and to assert that men are only so far virtuous as
they conform themselves to its dictates. Every
rational creature, ’tis said, is oblig’d to regulate
his actions by reason; and if any other motive or
principle challenge the direction of his conduct,
he ought to oppose it, ’til it be entirely subdu’d,
or at least brought to a conformity with that superior principle. . . . In order to shew the fallacy
of all this philosophy, I shall endeavour to prove
first, that reason alone can never be a motive to
any action of the will; and secondly, that it can
never oppose passion in the direction of the will.
(T, II, 3, 3, p. 265)
Hume’s claim that “reason alone” can never
motivate any action has clear moral implications,
for moral considerations can be motivators. We
sometimes refrain from doing something simply
because we judge that it would be wrong. If reason
alone cannot motivate an action, it seems to follow
that morality cannot be a matter of reason alone.
But what does this mean, that reason alone
can neither motivate an action nor oppose passion (e.g., desire or inclination)? Recall Hume’s
claim that “all the objects of human reason or enquiry may naturally be divided into two kinds,
to wit, Relations of Ideas and Matters of Fact” (HU,
108). If reason is going to motivate action, it must
do so in one of these two ways. Let us examine
each possibility.
Consider adding up a sum, which Hume takes to
be a matter of the relations of ideas. Suppose you are
totaling up what you owe to my dentist, Dr. Payne.
Will this reasoning lead to any action? Not by itself,
says Hume. If you want to pay Payne what you owe
her, this reasoning will guide what you do: you will
pay her the total and not some other amount. But in
the absence of that (or another) want, the reasoning
alone will not produce an action. The motivator is
the want; and a want is what Hume calls a passion.
Consider next these examples:
Ask a man why he uses exercise; he will answer because
he desires to keep his health. If you then enquire why
he desires health, he will readily reply because sickness
is painful. If you push your enquiries further and
desire a reason why he hates pain, it is impossible he
can ever give any. This is an ultimate end, and is
never referred to any object.
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Take any action allow’d to be vicious: Wilful
murder, for instance. Examine it in all lights, and
see if you can find that matter of fact, or real existence, which you call vice. In whichever way you
take it, you find only certain passions, motives,
volitions and thoughts. There is no other matter
of fact in the case. The vice entirely escapes you,
as long as you consider the object. You can never
find it, till you turn your reflexion into your own
breast, and find a sentiment of disapprobation,
which arises in you, towards this action. Here is a
matter of fact; but ’tis the object of feeling, not of
reason. It lies in yourself, not in the object. So that
when you pronounce any action or character to be
vicious, you mean nothing, but that from the constitution of your nature you have a feeling or sentiment of blame from the contemplation of it. Vice
and virtue, therefore, may be compar’d to sounds,
colours, heat and cold, which, according to modern
philosophy, are not qualities in objects, but perceptions in the mind. (T, II, 3, 1, 301)
Compare this analysis to Hume’s discussion of
causation. When we observe carefully any instance
of a causal relation, we never observe the causing
itself. We attribute a causal connection between
two things because long habit of seeing them together creates a feeling in our minds of a necessary connection between them. Moral judgments,
Hume is saying, resemble judgments of causality.
Here, too, we project onto the facts an idea with
an origin that is simply a feeling in the mind. In this
case, the feelings are those of approval and disapproval, which we express in terms of the concepts
“right/good” and “wrong/bad.” No matter how
closely you examine the facts of any action, you will
never discover in them its goodness or badness. The
moral quality of the action is a matter of how the
author of the moral judgment feels about them.
In a famous passage that widely influences subsequent moral philosophy, Hume marks out clearly the
distinction between the facts on the one hand (expressible in purely descriptive language) and the value qualities of the facts on the other (expressible in evaluations).
In every system of morality, which I have hitherto
met with, I have always remark’d, that the author
Reason can only be the “slave” of the passions. In
a few dramatic sentences, Hume drives this point
Where a passion is neither founded on false suppositions, nor chuses means insufficient for the end, the
understanding can neither justify nor condemn it.
’Tis not contrary to reason to prefer the destruction
of the whole world to the scratching of my finger.
(T, II, 3, 3, 267)
Reason is motivationally impotent; it cannot
rule. Its role is that of a slave! The master says,
“I want that,” and it is the job of the slave to figure
out how it can be got. The slave deals with means.
Reason has an important place in action, since if we
calculate wrong or make a mistake about the facts,
we will be likely to miss our ends. But those ends
are dictated by the nonrational part of our nature,
the wants and desires, the passions and sentiments,
that are simply given with that nature. If you truly
prefer the destruction of the world to the scratching
of my finger, there is nothing irrational about that.
The Origins of Moral Judgment
What, then, of morality? If moral judgments are to
have any effect on actions, they cannot be purely
rational judgments. They must be the expression
of passions of some sort. This is just what Hume
Let us again consider the two classes of things
subject to reason. Could morality be simply a
matter of the relations between ideas? There is a
conceptual relation between the ideas of murder
and wrongness: All murder is wrong—because
what “murder” means is “wrongful killing.” But this
can hardly be all that is involved in morality because
morality is supposed to be applied to the facts.
Just pointing out that murder involves the idea of
wrongful killing is no help at all when we are asking
of a certain action, Is this murder? So morality, if
it is going to have any practical effects, cannot be
merely a matter of the relations between ideas.
Can morality be a matter of fact (the second
province of reason)?
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things in fact have. It would be wrong—objectively
wrong—to treat a child and a rock the same way.
For Hume there are no value-facts. Value has
its origin in valuing—in feelings of desire, aversion,
love, hate, and so on. Values are projections onto
the facts, all of which have the same value—that is,
none. This is not to say that we should stop making
value judgments. As with causal judgments, Hume
admits we neither could nor should try to make
our way through life without them, even though
he takes his science of human nature to show that
neither is founded on reason.
The foundation of morality is to be found,
rather, in sentiment—in feelings of approval and
disapproval. A scientific examination of morality
ought to do more than discover these foundations,
however. It ought also to reveal what kinds of things
we approve and disapprove and why. Hume has
many interesting things to say about this matter,
but we’ll be brief.
Hume claims that we tend to approve of those
things which are either agreeable or useful,
either to ourselves or to others. Agreeable things,
such as white sand on a warm beach, naturally elicit
our immediate approval. Useful things, such as a
visit to Dr. Payne, are means to some agreeable
end. Hume believes that we often feel a kind of
approval for things agreeable to others, as well as
to ourselves. If Hume is right, an egoistic account
of human motivation (such as that of Hobbes) is
inadequate.* A Hobbesian might claim, of course,
that when we approve of another’s enjoyment we
do so because such approval is a means to our own
pleasure. But Hume argues that this can’t be right.
The pleasure or satisfaction we feel on viewing another’s enjoyment is our approval of it, so it could
not possibly be that for the sake of which we approve. Furthermore, we make moral judgments
about figures in past history, where there is no
possible impact on our present or future interests.
These judgments, Hume concludes, are caused
not by self-interest but by sympathy, which he
proceeds for some time in the ordinary way of
reasoning, and establishes the being of a God, or
makes observations about human affairs; when of
a sudden I am surpriz’d to find, that instead of the
usual copulations of propositions, is, and is not, I
meet with no proposition that is not connected with
an ought, or ought not. This change is imperceptible;
but is, however, of the last consequence. For as this
ought or ought not, expresses some new relation or
affirmation, ’tis necessary that it shou’d be observ’d
and explain’d; and at the same time that a reason
should be given, for what seems altogether inconceivable, how this new relation can be a deduction
from others, which are entirely different from it.
But as authors do not commonly use this precaution,
I shall presume to recommend it to the readers;
and am persuaded, that this small attention wou’d
subvert all the vulgar [i.e., common] systems of
morality, and let us see, that the distinction of vice
and virtue is not founded merely on the relations of
objects, nor is perceiv’d by reason. (T, II, 3, 1, 302)
Hume is here pointing to what is often called the
fact/value gap, or the is/ought problem.*
Reason can tell us what the facts are, but it cannot
tell us how to value them. And from premises that
mention only the facts, no conclusions about value
may be derived.
A contrast with Augustine may help clarify
Hume’s claim. For Augustine and other believers
in the Great Chain of Being, everything that exists
has a value. Some things—those nearer to God
and farther from nothingness—have more value
than others.† That’s just a fact, Augustine believes.
There is value in things, and it is incumbent on us
to adjust our desires to the degree of value that
*Reflection should tell you that this problem, too, is a consequence of the change produced by the development and acceptance of modern science. Dante’s world contained no such
gap; he could find the “right way” by discovering the facts about
the universe. In general, where final causes are an intrinsic part
of the way things are, no such gap exists. For the ends of things
are part of their very being. When final causes are cast out,
however, values lose their rootedness in the way things are.
†Take another look at the diagram of the Great Chain on
p. 272. *Compare Hobbesian egoism, pp. 411–413.
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Let us review:
• The principles governing the way ideas succeed
each other are nonrational principles—those of
sheer mechanical association, analogous in their
function to the principle of gravitation.
• All knowledge of anything beyond our perceptions depends on the relation of cause and
effect, but our idea of causality is rooted in nonrational habits.
• We have no reason to believe in a substantial
self; any such belief is a fiction foisted on us by
detectable mistakes.
• We have no reason to believe in God.
• Our actions are governed by nonrational
• Our liberty in action is not a matter of reason
freeing us from the causal order, but simply a
matter of nothing standing in the way of following our passions.
• Moral judgments, too, are founded on nonrational sentiments that are simply a given part of
human nature.
In every area, Hume discovers the limits of
reason. There is no good reason to believe in an
objective causal order, in the existence of a material world independent of our perceptions, in God,
in a soul or self, or in objective moral values. These
certainly seem to be skeptical themes. Is Hume,
then, a skeptic?
He makes distinctions among several kinds of
skepticism. Let us examine two. There is Descartes’ type, which Hume calls “antecedent
skepticism” because it is supposed to come before
any beliefs are deemed acceptable. Against this
sort, he makes two points. First, you cannot really
bring yourself to doubt everything. You find yourself believing in the reality of the world whether
you want to or not. Second, if you could doubt
everything, there would be no way back to rational belief; to get back, you would have to use your
reasoning faculties, the competence of which is one
of the things you are doubting.* So Hume dismisses
*Hume seems to be saying that we must be content with
the things we are “taught by nature,” as Descartes would say.
See Meditation III. Is this criticism of Descartes correct? Compare also the critique of Descartes by C. S. Peirce, p. 597.
understands as the tendency for the perception
of another’s situation to excite feelings similar to
those the other person is feeling. This is why perceiving another person’s agreeable experience elicits feelings of approval in our own minds.
We will not follow the development of Hume’s
ideas about the particular virtues, but we should
note one aspect. His insistence that morality is not
founded on reason would seem to catapult him directly into moral relativism because feelings seem
so personal. What I approve, we may think, might
be quite different from what you approve. But the
insistence on sympathy as an original passion in
human nature—within every individual—works
toward a commonality in the moral sense of us all.
It does not make moral disagreements between
cultures or individuals impossible, but it is a pressure built into us all that explains the large agreement in moral judgment we in fact find.
1. Explain what Hume means when he says that reason
is the slave of the passions.
2. How does Hume explain our judgment that a
certain action is bad or wrong or vicious? In what
do we find the viciousness of a vicious action?
3. What keeps Hume from complete moral relativism?
Is Hume a Skeptic?
On topic after topic, Hume sets himself against
the majority tradition in the West. But just as
Galilean and Newtonian science had overthrown
traditional views about the nonhuman world, it
should be no surprise that applying the same methods to human nature should have the same result.
Aristotle had defined man as a rational animal;
ever since, the emphasis had been on the “rational” aspect. In deciding what to believe, what to
do, how to live, and how to judge, philosophers
had looked to reason. The prerogatives of reason
had lately been exalted in an extreme way by Descartes, who held that we shouldn’t accept anything
unless it was attested by rational insight or rational deduction. What Hume thinks he has shown
is that if this is the right rule, then there is virtually
nothing we should accept.
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than another. Where am I, or what? From what
causes do I derive my existence, and to what condition shall I return? Whose favor shall I court, and
whose anger must I dread? What beings surround
me? and on whom have I any influence, or who have
any influence on me? I am confounded with all these
questions, and begin to fancy myself in the most
deplorable condition imaginable, inviron’d with the
deepest darkness, and utterly depriv’d of the use of
every member and faculty. (T, I, 4, 7, 175)
Reason has no answer to these questions. Depressing indeed!
What is the solution?
Most fortunately it happens, that since reason is
incapable of dispelling these clouds, nature herself suffices to that purpose, and cures me of this
philosophical melancholy and delirium, either
by relaxing this bent of mind, or by some avocation, and lively impression of my senses, which
obliterate all these chimeras. I dine, I play a game
of back-gammon, I converse, and am merry with
my friends; and when after three or four hours’
amusement, I wou’d return to these speculations,
they appear so cold, and strain’d, and ridiculous,
that I cannot find in my heart to enter into them
any farther. (T, I, 4, 7, 175)
We need not worry, he assures us, that the results of
philosophical study will paralyze us by taking away
all our convictions. “Nature,” he says, “is always
too strong for principle” (HU, 207). Custom and
habit, those nonrational instincts that are placed in
our natures, will ensure that we don’t sit shivering
in terror at our lack of certainty.
But Hume does not mean that we should cease to
pursue philosophy. Indeed, his conviction that nothing is more useful than the science of human nature
remains untouched. Only such a science can free us
from the natural tendency toward dogmatism and
superstition that plagues human society. Recalling his
classification of all knowledge into the relation of ideas
and matters of experience, Hume ends his Enquiry
Concerning Human Understanding with these words:
When we run over libraries, persuaded of these
principles, what havoc must we make? If we take
in hand any volume of school metaphysics, for instance; let us ask, Does it contain any abstract reasoning concerning quantity or number? No. Does it contain
Cartesian “antecedent” skepticism as both unworkable and barren.
There is another kind of skepticism, however,
which Hume thinks is quite useful. This is not an
attempt to doubt everything in the futile hope of
gaining something impossible to doubt, but an attempt to keep in mind “the strange infirmities of
human understanding.”
The greater part of mankind are naturally apt
to be affirmative and dogmatical in their opinions. . . . But could such dogmatical reasoners
become sensible of the strange infirmities of
human understanding, even in its most perfect
state, and when most accurate and cautious in its
determinations; such a reflection would naturally
inspire them with more modesty and reserve, and
diminish their fond opinion of themselves, and
their prejudice against antagonists. . . . In general
there is a degree of doubt, and caution, and modesty, which, in all kinds of scrutiny and decision,
ought for ever to accompany a just reasoner. (HU,
This mitigated skepticism, Hume says, makes
for modesty and caution; it will “abate [the]
pride” (HU, 208) of those who are haughty and
obstinate. It will teach us the limitations of our
human capacities and encourage us to devote
our understanding, not to abstruse problems of
metaphysics and theology, but to the problems of
common life.
In sponsoring such modesty about our intellectual attainments, Hume reflects Enlightenment
worries about the consequences of dogmatic attachments to creeds that have only private backing.
And if reason is really as broken-backed as Hume
says, then dogmatic attachment to what appears rational is just as worrisome. One of the virtues of
his examination of human nature, he feels, is that it
makes such dogmatism impossible.
There might be an opposite worry, however.
Could the consistently skeptical conclusions of
Hume’s philosophy leave us paralyzed? Hume
himself reports, in an introspective moment, that
after pursuing his research for a while, he finds
ready to reject all belief and reasoning, and [to] look
upon no opinion even as more probable or likely
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any experimental reasoning concerning matter of fact and
existence? No. Commit it then to the flames: For
it can contain nothing but sophistry and illusion.
(HU, 211)
Hume represents a kind of crisis point in modern
philosophy. Can anyone build anything on the
rubble he leaves behind?
1. What sort of skepticism does Hume criticize? What
sort does he advocate?
2. What does Hume hope his philosophizing will
accomplish? Does it do that for you?
1. Both Descartes and Hume can be compared to
Robinson Crusoe. Each tries to construct “a
world” out of the resources available only to an
isolated individual. Sketch the similarities and
differences in their projects, noting the materials they have available and the tools with which
they work.
2. Does Hume’s view of human liberty leave
room for responsibility? Compare Descartes on
free will.
3. How would du Châtelet explain Hume’s
skeptical-sounding conclusions? What mistake
would she say he made? How do the differences
in their views on the foundations of human
knowledge account for their disagreement on
this point?
framing hypotheses
Émilie du Châtelet
Republic of Letters
complex ideas
simple ideas
relations of ideas
matters of fact
a priori
constant conjunction
necessary connection
argument from design
a posteriori
fact/value gap
is/ought problem
antecedent skepticism
mitigated skepticism
1. Immanuel Kant, “An Answer to the Question:
What Is Enlightenment?,” in Perpetual Peace and
Other Essays, trans. Ted Humphrey (Indianapolis,
IN: Hackett, 1983), 41.
2. Kant, “What Is Enlightenment?,” 44.
3. From Newton’s Principia Mathematica, General
Scholium to Book III, reproduced in John Herman
Randall, The Career of Philosophy (New York:
Columbia University Press, 1962), 1:579.
4. Quotations and page numbers from du Châtelet’s
works are from Émilie du Châtelet, Selected
Philosophy and Scientific Writings, ed. Judith P.
Zinsser, trans. Isabelle Bour and Judith P. Zinsser
(Chicago: University of Chicago Press, 2009).
Quotations from the Discourse on Happiness are
marked DH; those from Foundations of Physics are
marked FP.
5. We have benefited from the excellent study of
Hume by Barry Stroud: Hume (London: Routledge
and Kegan Paul, 1977).
6. References to Hume’s works are as follows:
HU: Enquiry Concerning Human Understanding, ed.
Tom L. Beauchamp (Oxford: Oxford University
Press, 1999).
D: Dialogues Concerning Natural Religion, in Principal
Writings on Religion, ed. J. C. A. Gaskin (Oxford:
Oxford University Press, 1993), cited by part and
page number.
T: A Treatise of Human Nature, ed. David Fate
Norton and Mary J. Norton (Oxford: Oxford
University Press, 2000). Citations are by book,
part, section, and page number.
PM: An Enquiry Concerning the Principles of Morals,
ed. Tom L. Beauchamp (Oxford: Oxford
University Press, 1998).
7. Bertrand Russell, A History of Western Philosophy
(New York: Simon and Schuster, 1945), 567.
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Rehabilitating Reason (Within Strict Limits)
David Hume had published A Treatise of
Human Nature at the youthful age of
twenty-three, whereas Immanuel Kant
(1724–1804) published the first of his major
works, The Critique of Pure Reason, in 1781, when
he was fifty-seven. He enters the great conversation rather late in life because it has taken him
some time to understand the devastating critique
of Hume, “that acute man.”
Since the beginning of metaphysics, . . . no event
has occurred which could have been more decisive
in respect of the fate of this science than the attack
which David Hume made on it. (P, 64)1
I freely admit: it was David Hume’s remark that
first, many years ago, interrupted my dogmatic
slumber and gave a completely different direction
to my enquiries. (P, 67)
Kant sets himself to solve what he calls “Hume’s problem”: whether the concept of cause is indeed objectively vacuous, a fiction that can be traced to a merely
subjective and instinctive habit of human nature. We
have seen the skeptical consequences Hume draws
from his analysis; these, we can imagine, are what
wake Kant from his “dogmatic slumber.”
Human thought seems naturally to recognize no
limits. It moves easily and without apparent strain
from bodies to souls, from life in this world to life
after death, from material things to God. One aspect
of Enlightenment thought is the acute consciousness
of how varied thoughts become when they move out
beyond the ground of experience—and yet how
certain most people feel about their own views. This
is the dogmatism (or superstition) that Hume tries
to debunk. Stimulated by Hume, Kant, too, feels
this is a problem. It is true that in mathematics we
have clear examples of knowledge independent of
experience. But it does not follow (as thinkers such
as Plato suppose) that we can extend this knowledge indefinitely in a realm beyond experience.
Kant uses a lovely image to make this point.*
*Plato believes that the nonsensible, purely intelligible
world of Forms is not only knowable but also more intelligible than the world of experience and more real, too. See
pp. 152–155.
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The light dove, cleaving the air in her free flight,
and feeling its resistance, might imagine that its
flight would be still easier in empty space. It was
thus that Plato left the world of the senses, as setting too narrow limits to the understanding, and
ventured out beyond it on the wings of the ideas,
in the empty space of the pure understanding. He
did not observe that with all his efforts he made no
advance—meeting no resistance that might, as it
were, serve as a support upon which he could take
a stand, to which he could apply his powers, and so
set his understanding in motion. (CPR, 47)
Could the dove fly even better in empty space?
No, it could not fly there at all; it absolutely depends on some “resistance” to fly. In the same way,
Kant suggests, human thought needs a medium
that supplies “resistance” to work properly. In a
resistance-free environment, everything is equally
possible (as long as formal contradiction is avoided),
and the conflicts of dogmatic believers (philosophical, religious, or political) are inevitable.
Kant is convinced that Hume is right to pinpoint
experience as the only medium within which reason
can legitimately do its work. But Kant doubts that
Hume has correctly understood experience. Why?
Because Hume’s analysis has an unacceptable consequence. We did not explicitly draw this consequence when discussing Hume (because he does
not draw it). But if Hume is right, Newtonian science itself is basically an irrational and unjustified
fiction.* Recall that for Hume all our knowledge
of matters of fact beyond present perception and
memory is founded on the relation of cause and
effect. And causes are nothing more than projections onto a supposed objective world from a feeling in the mind.
Kant is convinced that in Newtonian science
we do have rationally justified knowledge. And if
Hume’s examination of reason forces us to deny
that we have this knowledge, something must be
*You can see that Hume ends up exactly where
Descartes fears to be, with science indistinguishable from
a dream. To escape this fate, Descartes thinks you need to
prove the existence of a nondeceptive God. But by undermining such proofs, Hume finds himself unable to escape
from solipsism—except by joining a game of backgammon
and ignoring the problem.
wrong with Hume’s analysis. What we need, Kant
says, is a better critique of reason—a critique
that will lay out its structure, explain its relationship
to its objects, and delineate the limits within which it
can legitimately work. Hume thinks that we need
a science of human nature. Kant agrees, but he sets
out to do a better job of it than Hume did.
Awakened from his dogmatic slumber, recognizing that, like the dove, he can no longer try to
fly in empty space, Kant makes an absolutely revolutionary suggestion:
Hitherto it has been assumed that all our knowledge must conform to objects. But all attempts to
extend our knowledge of objects by establishing
something in regard to them a priori, by means of
concepts, have, on this assumption, ended in failure. We must therefore make trial whether we may
not have more success in the tasks of metaphysics,
if we suppose that objects must conform to our
knowledge. . . . We should then be proceeding
precisely on the lines of Copernicus’ primary hypothesis. Failing of satisfactory progress in explaining the movements of the heavenly bodies on the
supposition that they all revolved round the spectator, he tried whether he might not have better
success if he made the spectator to revolve and the
stars to remain at rest. A similar experiment can
be tried in metaphysics, as regards the intuition of
objects. (CPR, 22)
This requires some explanation. Nearly all previous philosophy (and science and common sense,
too) has made a very natural assumption—as natural as the assumption that the heavenly bodies revolve around us. But perhaps it is just as wrong.
What is that assumption? It is that we acquire
knowledge and truth when our thoughts “conform
to objects.” According to this assumption, objects
are there, quite determinately being whatever they
are, completely independent of our apprehension
of them. To know them our beliefs must be brought
to correspond to these independently existing things.
Aristotle’s classical definition of truth expresses this
assumption perfectly: to say of what is that it is, and
of what is not that it is not, is true.* The assumption
*See Aristotle’s discussion of this on p. 187.
Critique 467
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is a basic part of the representational theory of
knowledge and perception (p. 372).
But Hume has argued that you can’t think
about representation in this way. Ideas that have
their origin in experience (e.g., green, warm,
solid) can go no further than experience. And
ideas that don’t (e.g., cause) are mere illusions.
By using such concepts, we can know nothing at
all about objects. All this follows if (1) we are acquainted only with the ideas in our experience,
(2) objects are thought to exist independent of
our experience, and (3) knowledge requires that
we ascertain a correspondence between ideas and
But what if this assumption has it exactly
backward? What if, to be an object at all, a thing
has to conform to certain concepts? What if objects couldn’t exist unless they were related to
a rational mind, set in a context of rational concepts and principles? Think about the motion of
the planets in their zigzag course across the sky.
On the assumption that this motion is real, accurate understanding remains elusive. Copernicus denies this assumption and suggests that the
motion is only apparent. On this new assumption,
we are able to understand and predict the behavior of these objects.
Perhaps, Kant is suggesting, the same is true
in the world of the intellect. Perhaps the objects
of experience are (at least in part) the result of a
construction by the rational mind. If so, they have
no reality independent of that construction. Like
the apparent motions of the planets, the objects of
our experience are merely apparent, not independently real. If this is so, it may well be that concepts such as causation, which cannot be abstracted
from experience (the lesson of Hume), still apply
to experience, simply because objects that are not
structured by that concept are inconceivable. The
suggestion is that the rational mind has a certain
structure, and whatever is knowable by such a
mind must necessarily be known in terms of that
structure. This structure is not derived from the
*Montaigne compares the problem to that of a man who
does not know Socrates and is presented with a portrait of
him. How can he tell whether it resembles Socrates?
objects known; it is imposed on them—but not arbitrarily, because the very idea of an object not so
structured makes no sense.
This is Kant’s Copernican revolution in
philosophy. To the details of this novel way of
thinking we now turn.
If we are going to take seriously this possibility
that objects are partially constituted by the rational mind, we must examine how that constitution
takes place. We need to peer reflectively behind
the scenes and catch a glimpse of the productive machinery at work—at the processes involved
in knowing anything at all. A prior question, of
course, is whether we can know anything at all, but
Kant thinks that Newton’s science has definitely
settled that question. Assuming, then, that a rational mind can have some knowledge, we want to
ask, How does it manage that? We need to engage
in what Kant calls “critique.” A “critical” philosophy is not one that criticizes, in the carping, censorious way where “nothing is ever right.” Critique
is the attempt to get behind knowledge claims and
ask, What makes them possible?
The objects of human knowledge seem to fall
into four main classes. We can see what Kant is up
to if we frame a question with respect to each of
these classes.
1. How is mathematics possible?
2. How is natural science possible?
3. How is metaphysics possible?
4. How is morality possible?
These are, in Kant’s sense, “critical” questions.
We are not going to develop mathematics, physics, metaphysics, or morality. But in each case
we are going to look at the rational foundations
on which these disciplines rest. What is it, for instance, about human reason that makes it possible
to develop mathematics? What structure, capacities,
and concepts must reason have for it to be able to do
These are reflective questions, which together
constitute a critique of reason, a critical examination of the way a rational mind works. Kant also
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1. Epistemological
1a. A judgment is a priori when it can be
known to be true without any reference to
experience. “Seven plus five equals twelve”
is an example.
1b. A judgment is a posteriori when we
must appeal to experience to determine
its truth or falsity. For instance, “John
F. Kennedy was assassinated” cannot be
known independent of experience.
2. Semantic
2a. A judgment is analytic when its denial
yields a contradiction. Here is an example Kant gives: “All bodies are extended.”
This is analytic because the predicate
“extended” is already included as part
of the subject, “bodies.” To say that there
is some body that is not extended is, in
effect, to claim there can be some extended thing that is not extended. And
that is contradictory. If an analytic judgment is true, it is necessarily true. The
opposite of an analytic judgment is not
possible. Since it is analytic that every
father has a child, it is not even logically
possible that there should be a father
without a child. Thus, every father necessarily has a child.
2b. A judgment is synthetic when it does
more than simply explicate or analyze a
concept. Here are some examples: “Every
event has a cause,” “Air has weight,” and
“John F. Kennedy was assassinated.” Consider the first example. The concept having
a cause is not part of the concept being an
event. This is something Hume teaches us.*
So it is not contradictory, though it may
be false, to say of some event that it has
no cause. The opposite of every synthetic
judgement is possibly true.
*Recall Hume’s claim that “all events seem entirely
loose and separate.” Neither experience nor reason, he
claims, ever discloses that necessary “connexion” that might
link them inseparably together. See p. 450.
calls this kind of investigation transcendental.*
A transcendental inquiry reaches back into the activities of the mind and asks how it produces its
results. If this kind of investigation succeeds, we’ll
know what the powers of reason are—and what
they are not. We can, Kant thinks, determine the
limits of rational knowledge. And if we can determine both the capacities and the limitations of
human reason, we may be able to escape both of
those evils between which philosophy has so often
swung: dogmatism on the one hand and skepticism
on the other. From Kant’s point of view, these
extremes are well illustrated by Descartes and
Hume, respectively.
1. What is the problem with the representational theory
of knowledge and perception that Kant thinks can be
resolved by imitating Copernicus? How does a
“Copernican turn” help?
2. What does a critique of reason try to uncover? In
what sense will the answers be transcendental?
Because all our claims to know are expressed in the
form of judgments, the first task is to clarify the
different kinds of judgments there are. Hume had
divided our knowledge into relations of ideas and
matters of fact.† Kant agrees that this is roughly
right, but not precise enough. Hume’s distinction
runs together two quite different kinds of consideration. (1) There is an epistemological question involved: Does a bit of knowledge rest on experience
or not? (2) There is also a semantic question: How
do the meanings of the words we use to express
that knowledge relate to each other? Kant sorts
these matters out, and the result is a classification
of judgments into four groups rather than into
Hume’s two.
*The term “transcendental” must be carefully distinguished from the similar term “transcendent.” See p. 480.
†Hume’s discussion of these is found on pp. 445–446.
Judgments 469
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judgments (e.g., “The water in the tea kettle is
boiling”) to general laws (e.g., “Water always
boils at 100°C at sea level”).
• Synthetic a priori: This is a puzzling and controversial class of judgments. If we were to know
such a judgment as true, we would have to be
able to know it quite independent of experience. This means that if such a judgment is
true, it is true no matter what our experience
shows us. Even if the events of experience were
organized in a completely different way, a true
judgment of this kind would remain true. And
yet it is not true because it is analytic; its denial
expresses a logical possibility.
We can represent these types in a matrix:
“Every mother
has a child.”
A priori
A posteriori
“There is a
Waterloo in
both Iowa
and Wisconsin.”
There is something very odd about synthetic
a priori judgments. Consider a judgment that is
about experience. Suppose that it is synthetic, but
that we can know it a priori. Because it is synthetic,
its opposite is (from a logical point of view) a real
possibility. And yet we can know—without appealing to experience—that this possibility is never
realized! How can this be?
Kant believes that the solution to the dilemmas
of past philosophy lies precisely in the recognition
that we possess synthetic a priori judgments. It is
his Copernican revolution in philosophy that makes
this recognition possible. Think: On the assumption that objects are realities independent of our
knowing them, it would be crazy to suppose that
we could know them without experiencing them
in some way; our thoughts about them would be
one thing, the objects something quite different;
These two pairs can be put together to give us
four possibilities:
• Analytic a priori: “All bodies are extended.” This
is analytic, as we have seen, because “extended”
is part of the definition of “body.” It is a priori
because we don’t have to examine our experience of bodies to know it is true; all we need is
to understand the meanings of the terms “body”
and “extended.”
• Analytic a posteriori: This class seems empty; if
the test for analyticity is examining a judgment’s
denial for contradiction, it seems clear that we
do not also have to examine experience. Every
analytic judgment must be a priori.
• Synthetic a posteriori: Here belong most of our
judgments about experience, from particular
“Two things fill the mind with ever new and increasing
admiration and awe . . . the starry heavens above me
and the moral law within me.”
–Immanuel Kant
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constituted by synthetic a priori judgments. The
objects we encounter are—in part—constructions.
And these judgments are principles for the construction of objects.
Kant sometimes calls a priori judgments “pure.”
By this, he means that they are not “contaminated”
by experience. We can now restate his questions
with a transcendental twist:
1. How is pure mathematics possible?
2. How is pure natural science possible?
3. How is pure metaphysics possible?
4. How is pure morality possible?
Let’s examine his answers.
1. Can you give examples of your own for each of the
four types of judgment?
2. Explain the idea of a synthetic a priori judgment,
showing clearly both its semantic and its
epistemological aspects.
3. What makes a priori synthetic judgments puzzling?
Geometry, Mathematics, Space,
and Time
It would be useful to have a criterion by which we
could distinguish a priori knowledge from a posteriori knowledge. Kant suggests that there are two
tests we can use: necessity and universality.
Experience teaches us that a thing is so and so, but
not that it cannot be otherwise. First, then, if we
have a proposition which in being thought is thought
as necessary, it is an a priori judgment. . . . Secondly,
experience never confers on its judgments true or
strict, but only assumed and comparative universality, through induction. . . . Necessity and strict universality are thus sure criteria of a priori knowledge,
and are inseparable from one another. (CPR, 43–44)
As Hume has taught us, necessity cannot be discovered by means of experience; as far as experience
tells us, all events are “entirely loose and separate.”
Further, because experience is limited in extent,
it cannot guarantee that a proposition is universally true (i.e., true everywhere and at all times).
It follows that if we find a judgment that is either
and they could vary independently.* What could
possibly guarantee that things would match our
thoughts a priori? On the traditional correspondence assumption, then, a priori knowledge that is
synthetic would be impossible.
But suppose that objects are objects only because they are structured in certain ways by the
mind in the very act of knowing them. Then it is
plausible to think that there might be principles of
that structuring and that some of these principles
might be synthetic. And those principles could be
known a priori—independent of the objects they
are structuring. So if Kant’s Copernican revolution
makes sense, there will be a priori synthetic principles for every domain of objects.
Kant’s examples of such principles may surprise
you. He takes the following to be synthetic a priori:
• all the judgments of mathematics and geometry;
• in natural science, such judgments as “Every
event has a cause”;
• in metaphysics, “There is a God,” and “The soul
is a simple substance, distinct from the body”;
• in morality, the rule that we should not treat
others merely as means to our own ends.
This is not to say we know all these judgments or
that they are all true. That remains to be seen. But
if you examine them, you should be able to see that
they are all examples of judgments that would have
to be known a priori (i.e., not from experience), if
at all. And examination should also confirm, Kant
thinks, that they are all synthetic. None of them is
true simply in virtue of how the terms are related
to each other.
Kant wants to understand how mathematics,
natural science, metaphysics, and morality are possible. In the light of his Copernican revolution,
we can see that he is asking how the rational mind
structures its objects into the objects of mathematics, natural science, metaphysics, and morality.
Implicit in the foundations of all these disciplines,
Kant thinks, are some judgments that do not arise
out of experience but prescribe how the objects
of experience must be. All four of these areas are
*Compare Ockham’s reflections on God’s omnipotence,
pp. 336–337.
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mysterious or occult. By “intuition” Kant simply
means the presentation of some sensible object to
the mind, such as our five fingers. We must “add
successively” the units presented in the intuition:
We count, one finger at a time. Knowing that
seven plus five equals twelve is a process. We construct mathematics by inscribing it on a background
composed of objects or sets of objects.
But we need to understand these objects more
clearly. If mathematics were only about the objects
of experience, it could be neither necessary nor
universal. We might know that these five oranges
and those seven oranges happen to make twelve oranges. But we wouldn’t know that all such groups
of oranges (examined or not) make twelve and
must make twelve. If we know this with necessity
and universality (as we surely do), the objects that
justify mathematical truths must themselves be
known in a purely a priori manner. There must be
pure intuitions, forms of pure sensibility. But what
could they be?
Now space and time are the two intuitions on which
pure mathematics grounds all its cognitions and
judgements. . . . Geometry is grounded on the pure
intuition of space. Arithmetic forms its own concepts of numbers by successive addition of units in
time. (P, 90)
Think about space a moment. According to
our ordinary experience, space is filled with things.
But suppose you “think away” all these things—
all the household goods, the clothes, the houses,
the earth itself, sun, moon, and stars. Have you
thought away space? Kant thinks not. (Newton
would have agreed.) But you have “subtracted”
everything empirical—that is, everything that gives
particular content to our experience. All that is left
is a kind of container, a form or structure, in which
empirical things can be put. But, since you have
gotten rid of everything empirical, what is left is
pure. And it can be known a priori. Geometry is the
science of this pure intuition of space.*
*Kant is referring to Euclidean geometry, of course.
Various non-Euclidean geometries were discovered—or
constructed—in the nineteenth century.
necessarily true or universally true, we can be sure
that it does not have its justification in experience.
Such a judgment must be a priori.
Mathematical truths are both necessary and
universal. They are, therefore, clear examples of a
priori judgments. But are they analytic or synthetic?
One might indeed think at first that the proposition
7 + 5 + 12 is a merely analytic proposition, which
follows according to the principle of contradiction
from the concept of a sum of seven and five. But if
we look more closely, we find that the concept of
the sum of 7 and 5 contains nothing further than
the unification of the two numbers into a single
number, and in this we do not in the least think
what this single number may be which combines
the two . . . and though I may analyze my concept
of such a possible sum as long as I please, I shall
never find the twelve in it. We have to go outside
these concepts by resorting to the intuition which
corresponds to one of them, our five fingers for
instance . . . and thus add to the concept of seven,
one by one, the units of five given in intuition. . . .
Nor is any principle of pure geometry analytic.
That the straight line between two points is the
shortest is a synthetic proposition. My concept of
the straight contains nothing of magnitude but only
a quality. The concept of the shortest is therefore
wholly an addition, and cannot be drawn by any
analysis from the concept of the straight line. Intuition, by means of which alone the synthesis is possible, must therefore be called in here to help. (P, 74)
Hume suggests that the truths of mathematics
are simply matters of how ideas are related to each
other—that they are analytic and can be known
by appeal to the principle of contradiction. Kant
argues that this is not so. For “seven plus five equals
twelve” to be analytic, the concept “twelve” would
have to be included in the concept “seven plus five.”
But all that concept tells us, if Kant is right, is that
two numbers are being added. It does not, of itself,
tell us what the sum is.
What can tell us what the sum is? Only some
intuition, Kant says.* An intuition is not anything
*Kant is the ancestor of a school in the philosophy of
mathematics that still has distinguished adherents. The viewpoint is called “intuitionism” but might more accurately be
termed “constructivism.”
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Consequently I do indeed admit that there are
bodies outside us, i.e. things which, although
wholly unknown to us, i.e. as to what they may
be in themselves, we know through the representations which their influence on our sensibility
provides for us, and to which we give the name of
bodies. This word therefore merely means the appearance of that for us unknown but nonetheless
actual object. (P, 95)*
Just as space is the pure intuition that makes
geometry possible, time is the pure intuition that
makes mathematics possible. Geometrical figures
are constructed on the pure (spatial) intuition in
which external objects are experienced. Numbers
and their relations are constructed on the pure
(temporal) intuition in which any objects (including mental events) are experienced. An elementary
example of constructing in time is counting, where
we construct one number after another.
Kant has now answered his first question. Pure
geometry and mathematics are possible because
their objects—space and time—are not independent of the mind that knows them; space and time
are pure forms of sensible intuition. He has shown,
moreover, that geometry and mathematics essentially involve judgments that are synthetic (because
they are constructive) and a priori (because they
are necessary and universal).
Because experience is always in time—and in
space as well if it is of external objects—it is a product of contributions from two sides: the objective
and the subjective. Nowhere can we know things as
they are in themselves. It is not as Descartes thinks,
that we know things-in-themselves in a confused
and inadequate way that can be continually improved. We do not know them at all! Of the objects we do experience, we can know a priori just
what we ourselves, as rational minds, necessarily
supply in experiencing them.
*Note that this conclusion squares with Locke’s belief
about the unknowability of substance. Here, however, that
conviction is set in a much more rigorous framework and
is much more adequately argued for. See pp. 418–419 for
Locke on substance.
But what is the status of the intuition itself?
Could space simply be one more (rather abstract
and esoteric) object independent of our perception
of it? Kant doesn’t think so. And the reason is this:
The truths of geometry, like those of mathematics,
are necessary. If you ask, “How likely is it that any
given straight line is the shortest distance between
its end points?” you demonstrate that you haven’t
understood geometry! Moreover, that a straight
line in a plane is the shortest distance between two
points is something we know to be universally true.
If space were an object independent of our minds,
knowing this would be impossible. We would have
to say that this is true for all the spaces we have examined, but beyond that—who knows? Geometers do
not proceed in this manner. They neither make experiments concerning space nor suppose that unexamined space could have a different structure. Yet
geometry is the science of space. How can this be?
The explanation must be this: Space is not
something “out there” to be discovered; space is a
form of the mind itself. It is a pure intuition providing a “structure” into which all our more determinate perceptions must fit. When you handle an
apple, your experience is constituted on the one
hand by sensations (color, texture, weight, and so
on) and on the other hand by a structure into which
these sensations fit (the pure intuition of space).
The apple is not an object entirely independent
of our perception of it. Part of that perception is
constituted by the intuition of space, which we do
not abstract from the experience, but bring to the
This has an important consequence. We cannot
experience the apple as it is in itself, independent
of our perception of it. Why not? Because part of
what it is to be an apple is to be in space; and space
is an aspect of our experience that comes from the
side of the subject. So we know the apple as it appears to us, not the apple as it is in itself. What goes
for the apple goes for the entire world. We can
only know how things appear.
Things are given to us as objects of our senses
situated outside us, but of what they may be in
themselves we know nothing; we only know their
appearances, i.e. the representations which they
bring about in us when they affect our senses.
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object through these representations. . . . Through
the first an object is given to us, through the second
the object is thought. . . . Intuition and concepts
constitute, therefore, the elements of all our knowledge, so that neither concepts without an intuition
in some way corresponding to them, nor intuition
without concepts, can yield knowledge. Both may
be either pure or empirical. When they contain
sensation (which presupposes the actual presence
of the object), they are empirical. When there is no
mingling of sensation with the representation, they
are pure. (CPR, 92)
Kant’s general term for the contents of the
mind is representation. He is here telling us
that our representations can be of several different
kinds: pure or empirical, intuitive or conceptual.
In fact, this gives us a matrix of four possibilities;
let us set them out with some examples:
Space and
God, the soul
Cherry pie,
otter, water,
the sun,
Sensations of
red, warm,
hard, etc.
We have not determined whether all these representations actually represent something, but we
know that any concept that does represent something will do so in tandem with some intuition.
For “neither concepts without an intuition . . . nor
intuition without concepts, can yield knowledge.”
The dove cannot fly in empty space.
Kant has contrasted sensibility with understanding, intuitions with concepts. But he is also
convinced that they must work together.
To neither of these powers may a preference be
given over the other. Without sensibility no object
would be given to us, without understanding no
object would be thought. Thoughts without content
1. Explain why Kant thinks that mathematical and
geometrical propositions are both a priori and
2. What is Kant’s argument that space and time must
be “pure” or a priori forms of intuition?
3. How do Kant’s reflections on space and time lead to
the conclusion that we can know things only as they
appear to us, not as they are in themselves?
Common Sense, Science,
and the A Priori Categories
Pure mathematics does not exhaust our knowledge. We know many things in the course of our
ordinary life and through Newtonian science. What
is the application of Kant’s Copernican revolution
in these spheres? One implication is that whatever common sense and science may reveal, they
cannot penetrate the veil of our pure sensible intuitions, which structure all possible objects in space
and time. Our knowledge will concern how these
things appear to us, not how they are in themselves.
To deal with his second question, how pure
natural science is possible, Kant needs to clarify a
distinction between two powers of the mind. He
calls them sensibility and understanding. The
former is a passive power, the ability to receive impressions. The latter is an active power, the power to
construct a representation of objects using concepts.
A concept, Kant tells us, is a kind of rule for
operating on intuitions. In itself, it needn’t have
any sensuous content at all. To have a concept is
to have an ability. And in the use of concepts the
understanding is active, not passive. Think of the
concept viper. To possess this concept is to be able
to sort snakes into vipers and nonvipers. Having
the concept is not having an image or a Lockean
abstract idea in your mind, as the empiricists believed. To have the concept is to be able to use a
rule for dividing the snakish parts of our experience
into categories or classes of things. Kant says,
Our knowledge springs from two fundamental
sources of the mind; the first is the capacity of
receiving representations (receptivity for impressions), the second is the power of knowing an
474 CHAPTER 20 Immanuel Kant: Rehabilitating Reason (Within Strict Limits)
mel70610_ch20_465-495.indd 474 06/30/18 07:47 PM
the understanding brings something of its own to
experience. In neither dimension is the mind just
“white paper” on which experience writes, as Locke
claimed. It is this rich source of structure in our experience, this transcendental organizing power, that
Kant wants to uncover through his critique of reason.
The question then forces itself upon us: What
concepts do we have that apply to objects but are
not derived from them? We are searching for a set
of concepts we use necessarily in thinking of an
object. These will be a priori concepts. Kant calls
them categories because they will supply the
most general characteristics of things: the characteristics it takes to qualify as a thing or object at all.*
We discover these concepts through critical
philosophy, which is reflective or transcendental in
nature. So we need to reflect on our thinking, to
see whether there are some features of our thinking
about objects that must be present no matter what
the object is.
Let’s begin by asking, What is it to think of
an object, anyway? Consider the contrast between
these two judgments:
a: “It seems as if there is a heavy book before me.”
b: “The book before me is heavy.”
What is the difference? In a certain sense, they both
have the same content: book, heavy, before me.
Yet there is a crucial difference. B is a judgment
about an object, whereas A pulls back from making
a judgment about that object. A is a judgment, not
about the book, but about my perception; it has only
what Kant calls “subjective validity.” B, however,
is a judgment about the book. It is an “objective”
are empty, intuitions without concepts are blind. It
is, therefore, just as necessary to make our concepts
sensible, that is, to add the object to them in intuition, as to make our intuitions intelligible, that is, to
bring them under concepts. . . . The understanding
can intuit nothing, the senses can think nothing. Only
through their union can knowledge arise. (CPR, 93)
In addition to the pure intuitions that can be
known a priori (i.e., space and time), we have empirical intuitions—what Locke calls “sensations”
and Hume calls “impressions.” Kant thinks of sensations as the matter of sensible objects. We can illustrate by imagining a square cut out of wood. The
spatial properties of a square (four equal straight
lines, four right angles) can be known a priori,
quite independent of its color or texture. But it
can only be some particular square if it is either red
or some other color, either smooth or less than
smooth. Our sensations determine which it is.
They provide the “filling” or content for the purely
formal intuition of a square.*
Are concepts like this, too? Do we have pure
concepts, as well as empirical concepts? Well, suppose there were concepts that we necessarily made
use of whenever we thought of any object at all.
Remembering that necessity is one of the marks of
the a priori, we would have to conclude that we
have pure or a priori concepts. This is, in fact, just
what Kant thinks; he is convinced that we make
use of pure concepts all the time. In fact, these
concepts—these a priori rules—do for our understanding exactly what the pure intuitions of space
and time do for sensibility: They give it structure
and organization. They make it possible for us to experience objects and not just a chaos of impressions.
Just as there are empirical intuitions, there are
empirical concepts. Just as there are pure intuitions, there are pure concepts.† Like sensibility,
*The pattern of thought here should remind you of the
distinction between matter and form in Aristotle and Aquinas; sensation plays the role of matter, and concepts play the
role of form. Though there is a structural similarity, there is
a fundamental difference: In Kant both members of the pair
have their being only relative to a mind. In this Kant shows his
debt to Locke and his successors. And in this Kant is characteristically “modern.”
†Check the examples again in the preceding chart.
*You can see that Kant is embarked on a project similar
to that of Aristotle: to discover the characteristics of being
qua being. Aristotle also produces a set of categories, displaying the most general ways in which something (anything)
can be. (See p. 185.) Kant goes about the project in a roughly
similar way: He looks at the language in which we talk about
objects. Between Kant and Aristotle, however, there stands
the Kantian Copernican revolution—and that makes a tremendous difference. Kant’s “categories,” the universal and
necessary features of objects, originate in the structure of
thinking about those objects. They apply not to being as such,
but to being as it is knowable by rational minds such as ours—
that is, to appearance.
Common Sense, Science, and the A Priori Categories 475
mel70610_ch20_465-495.indd 475 06/30/18 07:47 PM
this by canvassing all the possible forms objective
judgments can take. And he thinks he can do that
because he assumes that logic (the science of the
forms of judgment) is a closed and finished science;
no essential changes, he observes, have occurred in
it since Aristotle.* For each possible form of judgment, he finds an a priori concept that we bring
to bear on sensations. In each case, the application of this concept produces an a priori characteristic of the objective world of our experience.
Kant identifies twelve such categories—twelve
general ways we know that any objective world
must be. The fact that the world of our experience must be structured in terms of substanceshaving-properties is just one of these ways.
The a priori concept of substance gets an opportunity, so to speak, to apply to experience because sensations come grouped together in various
ways in space. Considered just as sensations, my experience of what I call the book hangs together in
a certain way; the color, texture, shape, and so on
move together across my field of vision. If this were
not so, I could scarcely unify these sensations under
one concept and experience one object, the book.
In a similar way, sensations also appear successively
in time. This provides a foothold for another of the
categories: causation.
We have examined Hume’s powerful argument
that our idea of cause is not an empirical idea—that
it is not abstracted from our experience.† Because
it contains the notion of a necessary connection between cause and effect, Hume concludes that the
idea is a fiction, a kind of illusion produced in us by
custom. So we cannot really know that objects are
related to each other by cause and effect.
But what if there simply couldn’t be objects at
all unless they were set in causal relations with each
other? What if the concept of causation (like the
concept of substance) is a necessary aspect of any
world of objects? This is the possibility that Kant’s
Copernican revolution explores. If nothing could be
objective for us without appearing in a context of
*We now know that Kant’s list of the possible forms
of judgments is not, as he thinks, complete. Logic has gone
through a revolution since Kant’s time.
†Review this argument on pp. 447–451.
judgment; whether true or false, it makes a claim
that an object has a certain characteristic.
What makes this difference? It can’t be the
empirical concepts involved, because “book” and
“heavy” and “before me” are the same in A and B.
Nor can the difference be anything derived from my
experience in the two cases, since my experience
may be exactly the same in each. So the difference
must be an a priori one. It seems to be a difference
in the manner in which the judgments are made, or
in the form of the judgments. If we can isolate the
feature that distinguishes B from A, we will have
put our finger on the contribution the understanding
makes to our experience of an objective world.
In this case, Kant tells us, the distinguishing
feature is that in B we are thinking in terms of a
substance together with its properties. These
concepts are not derived from what is given in my
sensations (since the sensations are exactly the same
in A). These concepts are brought to the experience
by the understanding in the very form of thinking of
the book as an object. The book is a substance that
has the property of being heavy. But this means that
the concepts “substance” and “property” are a priori
concepts—and that is just what we are looking for.
The point is this: In thinking of an objective
world, thinking necessarily takes certain forms of
organization. One of these forms consists of a kind
of logical function or rule: Structure experience in
terms of substances having properties.* Unless thoughts
take this logical form, Kant says, a world of objects
simply cannot be conceived at all. Without the application of these a priori concepts, there can be
no objective world for common sense or science
to know. So a world of objects is, like the world
of sensible intuitions, a composite. There is an empirical aspect to it (expressed in empirical concepts
such as “book” and “heavy”). But there is also an a
priori aspect to it (expressed in nonempirical concepts such as “substance” and “property”). Experience of an objective world requires both.
Kant works out an entire system of such a
priori concepts or categories. He thinks he can do
*To see the importance of this rule, contrast it with the
way that Buddhist philosophers understand the world around
us. See p. 41.

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