14 Descartes, Meditations VIa (AT
VII 71-80; cf. Discourse IV, AT VI 39-40) But now that
I am starting to gain a better understanding of myself and of tha author of my being, I do not, in fact, believe that I
should rashly accept all those things I appear to possess from my senses,
but, at the same time, [I do not think] I should call everything into doubt. — Meditations VI (AT VII 77-78) The first half of Meditations VI is devoted to
demonstrating two things: that bodies must exist in space outside of us, and
that the mind is distinct from the body (prior to Meditations VI, it has only been argued that we know our minds
better than our bodies, not that the thing in us that thinks cannot possibly
be a body). The second of these points
is established in the process of establishing the first. Descartes offered
three different arguments to prove that bodies must exist in space outside of
us: the first is supposed to establish the possibility of the existence of an external world by appeal to
what we clearly and distinctly perceive through the intellect; the second to
establish its probability by appeal
to what we picture in imagination, and the third to give us certainty of its existence by appeal
to what is given to us through the senses.
In the process of giving the second of these arguments, Descartes
introduced a principle that is central to his reasons for claiming that the
mind is distinct from the body, the principle that
whatever can be perceived separately can exist separately. This principle is explicitly articulated
and applied to establish the distinction of the mind from the body over the
course of the third argument. Thus,
the third argument ends up both demonstrating the existence of material
things and demonstrating that thinking things are radically different from
material things. Sandwiched in between
the second and third arguments is a review of what Descartes originally
believed about the nature of body, of his reasons for coming to doubt these
beliefs, and of what he was in a position to believe as of the close of Meditations V. It is tempting to skip over this review, both
because one assumes it will merely repeat points that have already been made
and because it is an irritating interruption to a chain of arguments. But the review makes many new points that
become important over the second half of Meditations
VI. These notes begin with a
consideration of that review before passing on to the three arguments. QUESTIONS ON THE
1. What sorts
of material things can at least possibly exist?
2. How does
imagination differ from understanding?
3. Why is imagination
not part of my essence?
4. Why is it
not without reason that people think that they sense bodies existing in space
outside of them rather than sense only their own thoughts?
5. What sort of things are taught to us by nature?
6. What
allowed Descartes to claim that the fact that I experience a pain in a
certain part of my body is not enough to prove that that part exists?
7. Why should
the fact that I can clearly and distinctly understand one thing without the
other entail that they are really different from one another?
8. Explain the
nature of the relation that Descartes supposed to hold between himself and
his powers of sensing and imagining.
9. Why would
God be a deceiver if my ideas of extended bodies were not caused by extended
bodies? A REVIEW Over the first part of
Meditations V, Descartes had
considered what we clearly and distinctly perceive in our ideas of
bodies. He had there reached the
conclusion that the ideas of extension could not be materially false, but
must be something positive and real.
But this is not to say that extended things must exist, or that if
they do they would have to be modified (cut up into numerous moving or
resting parts of different shapes and sizes) in exactly the ways that are
presented in our ideas. So it does not
bring us very far. It is natural to
ask whether some other means of obtaining knowledge might not put us in a
position to say something more.
Descartes accordingly proposed to take a second look at what we know
about body by means of the senses, and consider what reasons we originally
had for accepting those beliefs, what reasons we have for questioning those
beliefs, and what we should now think given what we have learned about
ourselves, God and the sciences of simple natures. Though it is billed as a “review,” this
second look brings many more things to light than were identified in Meditations I, and for that reason
alone it merits careful scrutiny. a. “First of all, I will review in my mind the
things I previously believed to be true, because I perceived them with my
senses, along with the reasons for those beliefs.” The principal things Descartes identified
as perceived by the senses are:
i. I have (or
even am in totality) an extended and shaped body
ii. This body
is surrounded by other extended and shaped bodies that can affect it for
better or worse
iii. My
sensations of pleasure and pain are indications of which bodies are affecting
me for better or worse
iv. I also
experience sensations of hunger, thirst, appetites of other sorts, and
passions such as fear or anger. These
feelings both inform me of disorders in my body and incline me what to do to
relieve that disorder
v. My
sensations of hardness, heat, and other tactile qualities, as well as of
light, colour, smell, taste, and sound, while sensed as my own personal and immediate
ideas, proceed from other bodies that differ from one another in virtue of
these different sensations they cause in me
vi. External
objects resemble the sensations they bring about in me
vii. There are
no ideas in my intellect which did not originate from sensory experience In recounting the
reasons that led Descartes to believe these things, it is best to begin with
item (v). Descartes identified three
reasons for thinking that my sensations are caused by other bodies. One is that they occur independently of my
will, so that I cannot make them go way in the presence of particular bodies,
or make them come about in the absence of those bodies. When I hear annoying music coming from the
next apartment, I cannot make it go away by an act of will. When I want to taste chocolate, I cannot
bring the sensation about by an act of will.
The second reason is that the ideas received from the senses have a
kind of vivacity that is not possessed by those same ideas when wilfully
recalled in the memory or wilfully conjured up in imagination. Remembered pain and imagined pain does not
hurt the way sensed pain hurts. Both
of these considerations led Descartes to conclude that his sensations did not
proceed from himself. The third reason
is only mentioned later, and is mentioned as one that preceded the other
two. It is that we are led to think
this way in advance of any reasoning by an instinct or natural impulse. We had to deal with the world as children,
before we developed any sophisticated reasoning capacities. At that point, we could not stand in awe of
our sensations, wondering what to do next about pains or pleasures or hunger
or thirst. We needed to think that
there is something outside of us that is causing pain, for example, and
impulsively withdraw from that thing.
Those instincts served us rather well. Whereas item (v) has
these three reasons in its favour, item (vi) has only the third. Apart from that, it is merely a counsel of
ignorance. Since we receive different
sensations under different circumstances, and since we have reason to think
the sensations are caused by objects other than ourselves, there must be
differences in the objects present in different circumstances that account
for our different sensations. But we
have no idea what those differences may be.
In our ignorance, we adopt the plausible hypothesis that the objects
are something like our sensations, and that is why they give us those
sensations. But as plausible (i.e.,
tempting) as this hypothesis is, there is no justification for it. It is merely a stop-gap for our
ignorance. What induces us to propose
and accept it is really a natural impulse or instinct. Item (vii) results
from the fact that we grew up using our senses before we developed our
intellectual capacities. As a consequence,
most of our ideas were first obtained from the senses, and as the ideas we
later form independently of the use of the senses do not have the vivacity
characteristic of sensory ideas and most of them include copies of ideas
originally obtained from the senses, it is easy to leap to the conclusion
that all our ideas are obtained from sensory experience. Let’s now return to
items (i) and (ii). I see and touch my
own body as I see and touch other bodies.
So from the perspective of these senses, it would appear as just one
object among others but for one thing: I see and touch all other bodies from
the perspective point occupied by my body.
Moreover, when objects hurt my body, the pain stays in my body when I
move away from them, rather than staying in the other objects. Likewise, I cannot satisfy my hunger or
thirst by feeding or watering other bodies.
These experiences and others like them lead me to identify my body as one
that specially belongs to me. But I have no
experiences or reasons that lead me to items (iii) and (iv). In many if not most cases I don’t know what
it is about painful bodies that is doing damage to my body or what form that
damage takes. I just know that it
hurts and I feel natural inclination to pull away. Likewise, I can’t identify anything that
connects the feeling of thirst with the impulse to drink water, and yet the
feeling naturally inclines me to want to engage in that action. To sum up, there are
two main reasons for the sensory beliefs that have been itemized. The original reason is a natural
impulse. But some of the beliefs have
further reasons grounded in the character of our sensory experiences: their
independence from our will, their special kind of vivacity, and the fact that
some of them get carried around with me or my body wherever I go whereas
others seem to remain behind in objects outside of my body. b. “The I will also assess the reasons why I later
called them into doubt.” Descartes’s statement of reasons for doubting sensory
beliefs gives pride of place to the fact that my senses occasionally deceive
me. Subsequent sense experiences show
me that earlier sense experiences misrepresented the objects, or at least
leave me uncertain which sensory experiences are the accurate ones. This reason is the one given first and it
is discussed in most detail. The
dreaming argument is mentioned only later as one of two “general
considerations,” the other being that I might be constituted in such a way
that I would make mistakes even in matters that I consider most true. However, this second “general
consideration” has already been abandoned (Descartes mentioned in passing
that it rests on considerations that he only assumed were valid). Given the way it is lumped in with an
argument that has already been discredited, and only mentioned without any
detailed consideration, one gets the impression that the dreaming argument
has lost force in Descartes’s eyes. Of particular interest is a new
consideration that makes its first appearance here. This is the “phantom limb” argument. People who have had an amputation will
report feeling pain in the limb that no longer exists. This is a striking phenomenon that shows
that pains may only exist in the mind, not where they appear to be, at
locations in body parts. They may not,
therefore, signify that there is some sort of disorder in a body part. For in this case there is no part to be
disordered. Expanding on this
consideration would lead us to infer that there is no sensory experience that
is adequate to convince us that we have a body. In addition for
reviewing his reasons for rejecting sensory beliefs, Descartes took a second
look at his reasons for accepting sensory beliefs. The principal reason, that these beliefs
arise from a natural impulse or instinct, is one he rejected on the ground
that nature pushes us to accept many things that reason opposes, for instance
that the sun orbits around the earth.
The further reason, that ideas of sense arise independently of my will
and have a special vivacity, is one he rejected on the ground that there may
be some other faculty in me that is responsible for producing these ideas
independently of recourse to the will.
We already know this from earlier meditations. We are being reminded of it because, as we
will see in what follows, he meant to draw these particular sceptical
considerations into question. The
first is no longer as solid as it once was given that it has been
demonstrated that God exists and is no deceiver. And the second falls afoul of a distinction
Descartes is about to draw between what is essential to me insofar as I am a
thinking being and what does not need to belong to me. c. “Finally I will consider what I ought to
believe about them now.”
Descartes closed this review by alerting us to the fact that his
sceptical conclusions would now need to be reassessed. There may be more to the reasons for
relying on sensory beliefs than he had allowed, even if we cannot
rehabilitate all of beliefs (i)-(vii) in their original form. “I do not, in fact, believe that I should
rashly accept all those things I appear to possess from my senses,” he wrote,
“but at the same time, [I do not think] I should call everything into doubt.” THE POSSIBILITY PROOF FROM UNDERSTANDING Descartes began by
observing that the existence of material things or bodies is at least
possible. This brief proof takes up
the first half of the first paragraph of Meditations
VI. Put more formally, and more
plainly, Descartes’s argument looks like this: 1. God can create anything that is not
impossible, absurd or contradictory (from the fact that God is all-powerful) 2. Nothing that can be clearly and distinctly
perceived could be impossible, absurd or contradictory (from Meditations IV). 3. Therefore, anything that can be clearly and
distinctly perceived could be created by God (from 1 and 2) 4. My ideas of bodies can be clearly and
distinctly perceived, at least insofar as they contain just what is described
by mathematics and geometry (i.e., extension, duration, motion and their
modes) (from Meditations V) Conclusion: It is at least possible that God could have
created extended, enduring, and movable bodies (from 3 and 4). Note that the fourth
premise of this argument limits the kind of bodies that we can know God to
have possibly created just to bodies that have the primary and real qualities
of size, shape, position, motion, and so on.
Sensible qualities like colour and solidity are not mentioned. This is a consequence of the possible
material falsity of our ideas of these qualities, discussed in Meditations III. If we are going to make claims about what
God might possibly have created, we have to be sure that what we have in mind
really is something, and not nothing.
But insofar as it is an open question whether sensible qualities are
ideas of real, positive things or confused perceptions of nothing at all, it
remains an open question whether there would be anything for God to create
answering to our ideas of sensible qualities.
Perhaps God just created minds that confusedly perceive nothing as if
it were sensible qualities (or, alternatively, perhaps God just created minds
that confusedly perceive the more primary and real qualities of extension and
its modes as if they were sensible qualities). Of course, it might
also have been the case that God just created minds that have ideas of the
primary and real qualities, without actually making objects that in any way
resemble those qualities. But it is at
least possible that God might have created something corresponding to these
ideas as well, whereas we cannot affirm this concerning sensible qualities. THE PROBABILITY PROOF FROM IMAGINATION The second proof is
somewhat stronger and establishes a probability rather than a mere
possibility of the existence of bodies. The proof proceeds by
remarking on the strange fact that we have such a thing as an imagination at
all. The imagination merely serves to
allow us to vividly picture some (but not all) of the things we can quite
well conceive with our intellects. In
other words, it is a redundant function.
This sudden talk of a separate faculty of imagination may seem
bewildering in light of Descartes’s claim, in Meditations II, that there is only one
cognitive faculty, the understanding, which images and senses as well as
understands. But even though Descartes
rejected the existence of three distinct faculties, he did think that the
understanding grasps two distinctly different kinds of ideas. Some ideas are literally like images or
pictures. They seem, as it were, to
take up space and to consist of spatially arrayed parts. Others are more like definitions or lists
of essential features that a thing must exhibit. They seem to be merely formulae in accord
with the things we can picture are made.
Thus, imaging or picturing a triangle is one thing, and grasping the
concept of a triangle or understanding what it means for something to be a
triangle is something else. Though
both the image and the judgment are thoughts grasped by the understanding,
Descartes often said that when the understanding has thoughts of the former
kind it has a special kind of thought and should be said to be imaging or
sensing, whereas when it has thoughts of the latter kind it understands in a
more proper and narrower sense (see, for instance, AT VII 78). Descartes illustrated
this point with examples of geometrical features. Triangles and pentagons may be imagined as
well as understood; that is, we can image or picture them, as well as simply
grasp the definition or list the conditions that have to be satisfied for
something to be a triangle or pentagon.
We are aware by introspection that these two acts, getting an idea
that is a literal image or picture in the mind’s eye and judging about the
content, are very different acts and involve, as Descartes put it, different
“efforts” on the part of the mind. We are also aware that
imagination is redundant — that everything that can be imagined can be
understood, but not everything that can be understood can be imagined. A hundred- or thousand-sided figure, though
it may be very clearly and distinctly understood in all its aspects, cannot
be brought to an image — at least not any image adequate for us to
distinguish that figure from a 99- or 999-sided figure, or indeed from a
circle. (Any image of such a figure
would have to be “confused” in the technical sense of the term, though the
idea had of the same figure by the intellect would be “distinct.”) Our imaginations
therefore seem to be a kind of annex to our cognitive powers. We would still be able to think the same
things if we lacked them. This led
Descartes to claim that our imaginations are separable from us. They must be separable because we would
still exist as the same sorts of being with all the same abilities if we were
to lose them. So they cannot be part
of our essence, that is, part of what makes us what we are. They would seem to reside in something
distinct from us, to which we are merely contingently attached. There is an important
principle that is tacitly invoked here, the principle that if one thing is
conceivable apart from another (for example, if I as thinking being am
conceivable apart from any capacity to imagine),
then those two things must be at least logically separate. Even if in fact they are always encountered
together in experience, the one could in
principle exist without the other.
This is what, in the literature, is called the separability principle: Separability
principle: Whatever things can be conceived separately
from one another must be really distinct, and separable in principle from one
another. The separability
principle is the inverse of the principle concerning clear and distinct
perception operative in Meditations
IV, where it was claimed that if we clearly and distinctly perceive one idea,
and find another contained in it, then we must judge the two are
related. Here, if we clearly and
distinctly perceive one idea, and do not
find the other related to it, then we can judge that the two have nothing
to do with one another, so that God could create the one apart from one
another. Even if they in fact always
occur together in our experience, their conjunction is merely accidental or
coincidental. Some examples might
help to illustrate this claim. I can
think of an apple without having to think of redness. The apple is in this sense separable from
redness and could at least in principle exist apart from it, even though in
fact a lot of apples might be red. Or,
I can think of a city without thinking of it as having a police force. There might be no city without police but
it is at least conceivable that there might be one, and so it seems at least
possible that such a place might exist.
But I cannot conceive of an apple without conceiving of a fruit, or a
city that has fewer than two buildings.
These latter things cannot be conceived separately from one another
and Descartes took this as an indication that they might well not be able to
exist separately. But be that as it may, we can be sure that if one thing can
be conceived without having to think of another, then it must be essentially
distinct from the other (in the sense that the form or essence that makes
that thing what it is involves nothing that goes into the form or essence
that makes the other thing what it is), and so could exist apart from it. Descartes used this
principle to powerful effect in what follows. To return to the main
argument, having speculated that our imagistic ideas could well depend on
something distinct from us, to which we are merely contingently attached,
Descartes went on to ask what such a thing might be. The most characteristic feature of our
ideas of imagination is that they are pictures of things. They seem to take up space and to consist
of spatially arranged parts. Accordingly,
he speculated that perhaps there is something attached to us that is actually extended in space, like a little theatre
screen or a canvas on which pictures can be projected or painted. The intellect could then get two different
kinds of ideas, one that it receives when it turns to contemplate this canvas
or screen and the other when it merely judges about the ideas it finds within
itself. In the former case, the
pictures on the stage or screen would be the objects that the ideas in the
intellect are about (they would supply the objective reality for our ideas of
imagination). However, it is important
to stress that they would not be
those very ideas. The mind’s ideas,
whether they are imagistic ideas of imagination or sense, or whether they are
judgments of the understanding, exist only in the mind, which cannot be
affirmed to be extended (and will soon be proven to be unextended). The pictures on the extended, physical
organ that we might call the corporeal imagination are at best causes of a
particular kind of imagistic idea being created in the mind. The intellect would experience these
imagistic ideas in a very different way.
Rather than “judge” them as something it finds within itself, it would
“envisage” them as if they were present before it, and this would account for
the peculiar vivacity of imagined ideas as well as for our sense that they
are very different from the other ideas formed by the intellect and in a
sense the result the operation of a distinct knowing power. This theory may seem
too speculative, and Descartes himself did not presume to claim that we can
know for sure that this is what causes the intellect to have imagistic
ideas. But he did think the theory is
highly probable. The theory is in fact
just the theory of the operation of the imagination described by Aristotle in
De Anima III and accepted as dogma
by theorists of perception and knowledge for centuries. According to that theory, there is actually
a bodily organ, just like the eyes or ears, but located inside the body
somewhere, probably in the brain, that receives imprints or images from
external objects. The intellect was
supposed to form many or even all of its ideas by “contemplating” the images
impressed by the external sense organs on the soft matter of this internal
organ and then subsequently abstracting the universal “form” from the
particular way in which the matter of the sense organ is impressed. The main difference between Descartes’s version of the theory and Aristotle’s is that
Aristotle took the physical organ in the body to itself be the imagination
and imagining to just consist in the imprinting of
this organ. Descartes, in contrast,
takes imagining to be a special act of the mind or
intellect, involving getting a unique kind of idea through somehow turning to
and contemplating the organ. And, of
course, Descartes did not accept that the intellect must get all of its ideas
by contemplating images impressed by the senses on the imagination. This supposition would contradict his
position on the innate idea of God, and a little further on in Meditations VI, he explicitly
condemned it. To return to the
argument, if Descartes’s account of the operation
of imagination were correct, it would imply that at least one extended body
must exist, namely the part of our brains that we contemplate when we get
ideas of imagination. This is why
Descartes said that a consideration of the nature of our imagination
establishes at least a probability that bodies might exist. However, Descartes had
to admit that the proof does not establish a certainty of the existence of a
corporeal imaging organ. Perhaps other
explanations could be found for the difference between ideas of imagination
and those of understanding that would not need to invoke these same
presuppositions. THE ACTUALITY PROOF FROM THE NATURAL IMPULSE OF THE SENSES Descartes final and
most decisive proof for the existence of bodies takes off from the natural
impulses he had found to be the original reasons for our sensory
beliefs. These impulses now need to be
understood in the light of what Descartes has learned about the goodness of
God and about what is separable from and what is proper to his nature, when
he is considered as a thinking being. In the process of
giving this final proof, Descartes uncovered an argument for concluding that
the mind must be a radically distinct kind of thing from the body. This discovery helps his proof for the
existence of bodies along. It also
helps to demonstrate that his mechanistic philosophy does not reduce everything
to matter and can provide for the existence of an immortal soul. The
proof for the real distinction of the soul from the body. The argument Descartes proceeded to give
for the “real distinction” of the soul from the body appeals to the
separability principle introduced earlier.
He pointed out that I am able to know that I must exist, but despite
this fact am still able to doubt that I have a body. In other words, I can conceive of myself
very clearly and distinctly as a being that senses, imagines, thinks, wills,
desires, affirms, doubts, denies, and feels, and cannot doubt that I exist
and do any of these things when I experience myself doing them — but I can
doubt that I have eyes, hands, brain, or any sort of physical body. The dreaming argument already sufficed to
establish that. But, Descartes
continued, if one thing (for example, the thinking part of a person) may be
very clearly and distinctly conceived without having to include another thing
(namely, extension) in the conception, then those two things must be
essentially distinct. The one
(thinking and its modes) must have nothing to do with the other (extension
and its modes), so that were the one separated from the other (extension
removed from the thinking thing), it could continue to exist on its own. If this were not the case — if separating
the thinking part from the extended part were to destroy the thing, then we
should not be able to distinctly perceive the thinking part without realizing
that some idea of extension must be included in it as part of its
essence. A distinct perception of an
idea, as noted earlier in connection with Meditations
V, is one that contains separate ideas of all the parts of that idea. Any
necessary connections between two things would have to be revealed by such a
perception. So being able to clearly
and distinctly conceive of thought and all of its modes (sensing, imagining,
believing, doubting, conceiving, willing, desiring, feeling, etc.) while
still being able to doubt whether the thinking being is extended, proves that
the latter really may be separated from the former. By similar argument,
since we can conceive of extension and its modes (size, shape, position,
motion, order) without having to conceive of any of
the modes of thought, body must be similarly distinct from mind and capable
of existing apart from it. This does not rule out
the possibility that I might still be joined to a body. The point of Descartes’s
argument is just that I am in principle separable from any bodies that I may
be joined to. Descartes wanted to go
on to claim that I do in fact have a body, but he insisted that I am not so
intimately united to my body that I could not be removed from it without
being destroyed. What I really am is
just the thinking part, which is a sort of detachable module that can, at the
will of God, either be connected to a body or removed from it without its own
integrity being in any way undermined. The
proof for the existence of bodies. Descartes’s final
proof for the existence of material things appeals to the fact that I do not
just understand the properties of extension or have imagistic ideas of
bodies, but also have sensory ideas of bodies. Like my ideas of imagination, my ideas of
sensation are pictorial in nature and involve “envisaging” bodies “as if they
were present.” But unlike my ideas of
imagination they do not occur consequent upon an
effort of my will. Instead, when I form them, I experience myself as
something passive that is being affected by something else. For, rather than require any effort on my
part, the formation of these ideas happens without my wanting it and
frequently even contrary to my wishes.
I can both fail to get ideas of sense when I want to have them, and
have them when I do not want them.
This gives me a “natural impulse” to consider these ideas to have been
created by something else. Of course, just
because I have no control over my ideas of sense, it does not follow that I
do not cause them, and just because I have a natural impulse to suppose they
have some external cause, it does not follow that I myself do not cause them,
or that they could not be caused by some other being that, like myself, could
serve as an “eminent” cause of ideas of extension. All that follows is that whatever it might
be that causes these ideas is something that operates independently of my
will. Moreover, natural impulses are
not the same things as clear and distinct perceptions. When I have a clear and distinct
perception, it compels my will to assent.
But natural impulses can be resisted.
And some of them are contrary to what I clearly and distinctly
perceive, which proves that they are not to be trusted. These are the points Descartes had made at
the close of his review, at AT VII 77. But these concerns don’t
sit well with what has since been established about my own nature and about
God’s nature. Suppose there were some
hidden faculty in me that produces my ideas of
sensible qualities independently of my will.
Then simply for the reason that this faculty is hidden and that ideas
do not seem to come from anything in me, it follows that I can clearly and
distinctly perceive myself without having to include the thought of any such
faculty as being a part of me. This
means that, even if I do have such a faculty, it would be an unnecessary
add-on to my being. God would not have
needed to create me with it. But then
why would God have created me with such a faculty? Things get worse when
we consider that I also have a natural impulse to believe that my sensory ideas
of bodies come from things that exist apart from me. Even granting that there are some natural
impulses that are contrary to what I clearly and distinctly perceive, this
particular natural impulse is not among them.
I may have doubts and wonder whether bodies exist outside me or
not. But I do not clearly and
distinctly perceive that it is impossible that there should be bodies
existing outside of me. On the
contrary, I clearly and distinctly perceive that it is entirely possible that
there may be such things, at least insofar as they are considered to be forms
of extension. Descartes recognized
that God might have reasons for allowing me to fall into error. But he insisted that the goodness of God
would not permit him to allow me to fall into error unless I were given ways of discovering and correcting my
mistake. But if it is wrong to believe
that there are external objects, I would seem to have no way of discovering
the error of that belief. If God gave
me a strong natural impulse to believe that my sensory ideas come from
external objects when there are no such objects, and when all those ideas are
eminently caused by himself or some other spirit or, worse, some hidden
faculty in myself, and if God could very well have created me without that
impulse and without that hidden faculty without diminishing me in the least,
then it is hard not to conclude that God must be a deceiver. Since God is no deceiver, we seem compelled
to accept that external objects must exist. This is a complex
argument, so let’s run through it a second time from a different angle. Why, Descartes asked, would an all-good God
have put something into me that causes particularly vivid ideas of sensation
independently of my will, and so triggers an instinctive impulse to think
that these ideas do not come from me but from other things outside of me? We cannot think that God had to do
this. For, Descartes claimed, I
clearly and distinctly understand that it is possible for a thing to think
without also having to sense.
Accordingly, the separability principle dictates that it ought to have
been possible for God to have created me without a capacity to produce ideas
of sensation, had he wished to do so.
Nor can I think that his doing so would necessarily have made me any
worse off. Were there nothing outside of me that corresponds to my ideas of
sensation and were all my ideas of sensation merely caused by something in me
that invents these ideas independently of my will, then I would not be
diminished in the least were I to lack this capacity and not get any ideas of
sensation. After all, everything that
I can sense, I can just as well understand.
Were my sensory capacity to serve no other purpose than to invent
fictional ideas that teach me nothing that I could not just as well learn
from unassisted understanding, it would be superfluous. Indeed, it would be worse than superfluous,
since insofar as it makes my ideas occur independently of my will it tempts
me to suppose that the ideas are caused by something outside of me.
Admittedly, after what I have learned from Meditations IV, I can resist the temptation to make this hasty
judgment. But I cannot deny that I
feel a strong natural impulse to make it anyway, and that before I was
instructed by Meditations IV I even
gave in to it. But that impulse is
just as unnecessary as the sensory capacity.
I did not need to be created with it.
And given that I was created with it, I have no way of discovering the
error of what it tells me. Even though
I may not clearly and distinctly perceive the truth of what it tells me, I
also do not clearly and distinctly perceive that what it tells me is in
error, and that there are no external objects. If I need not have been created with a
mental capacity, and if the use of that capacity serves no other purpose than
to deceive me, or to tempt me to into deception, then an all-good God would
not have given it to me. If I have ideas of sensation and a strong natural
impulse to think that I am not there cause, this cannot be because I myself
am producing them unknown to myself. An all-good God would simply not have made
me that way. So something else must be
producing my ideas of sensation. What would such a
thing be? According to what Descartes
had already established in Meditations
III, it would have to be something that “formally” or “eminently” contains at
least as much as is represented in my ideas of sensation. This means that it would either have to be
something that itself literally (i.e., “formally”) contains all the reality I
find in my ideas of sensation, or else something that is able to “eminently”
cause all this reality. Recall that
Descartes considered our ideas of sensation to consist of shaped and sized
pieces of extension that have sensible qualities like colour, solidity, and
heat attributed to them (Meditations
III). Recall further that he
maintained that sensible qualities might not be “real,” but might be
materially false ideas that we ourselves cook up when our senses are not
affected by anything real (Meditations III). However, extension and its modes (shape,
size, number, and motion) definitely are something real with a nature
independent of us, as is proven by the fact that we cannot legislate the
content of the principles of geometry and arithmetic (Meditations V). Recall
finally that Descartes maintained that even if, as we have just learned, we
ourselves could not be the cause of our ideas of extension, other unextended
spirits, such as angels, demon deceivers or God might nonetheless still be
eminent causes of these ideas (Meditations
III). So at this point it looks as
though the cause of our ideas of sensation would either have to be bodies
that are themselves actually extended (though not necessarily possessed of
any sensible qualities) or else unextended spirits with special powers to
“eminently” create ideas of extension in us. At this point
Descartes appealed to our natural inclination to suppose that our ideas of
sensation are caused by objects that are at least something like the objects
those ideas depict. Were this
propensity wrong, I do not see how I could ever discover my error. The fact that sensible qualities occur in
opposed pairs might alert me to the possibility that one or both members of
each pair might be a “materially false” idea of nothing, but I can find no
evidence that suggests that my ideas of extension proceed from nothing. Consequently, Descartes maintained, were
the cause of my ideas of sensible things not extended, God would be a
deceiver, either for giving me ideas of sense that do not refer to anything
that actually exists when I could perfectly well exist without those ideas,
or for giving me an incorrigible propensity to believe that my ideas of sense
proceed from extended things when they are in fact caused by other
spirits. Since God is no deceiver, we
can infer that neither of these things is the case. Our ideas of sensation are not caused
either by God himself or by other spirits.
It remains that they are caused by objects that are literally
extended. This argument has
proceeded at some length, but its main points may be quite briefly
summarized. 1. I have an incorrigible natural inclination
to suppose that my ideas of sensation are not caused by me, and an
incorrigible natural inclination to suppose that they are caused by something
that formally (i.e. actually) contains at least as much as I clearly and
distinctly perceive to be a real feature of those ideas. 2. God did not have to give me either of these
inclinations. 3. Therefore, God would be a deceiver were my ideas
of sensation not caused by something outside of me that formally contains at
least as much as I clearly and distinctly perceive to be a real feature of
those ideas. 4. God is no deceiver. 5. Therefore, the cause of my ideas of
sensation must formally contain at least as much as I clearly and distinctly
perceive to be a real feature of those ideas. 6. I clearly and distinctly perceive extension
to be a real feature of my ideas of sensation. 7. Therefore, extended objects (i.e. material
things) must exist. Note that this
argument only allows us to infer that the bodies that cause our ideas of
bodies must formally contain all the reality
that is represented in our ideas of bodies.
This allows us to infer that the cause of our ideas of bodies must be
something that is extended, since extension is represented in our ideas of
bodies, and, as Meditations V has
shown, our ideas of extension contain something true and real. However we
cannot legitimately infer that the cause of our ideas must be extended in
exactly the same way that our ideas are extended. Just as any geometrical shape could be
thought to be contained on a blank piece of paper, so any extended thing
could be the “blank space” that serves as the formal cause of any shape
whatsoever. Moreover, the argument
does not allow us to infer that the cause of our ideas of extension must have
any sensible qualities. For, as the
discussion of material falsity in Meditations
III demonstrates, questions can be raised about whether the sensible
qualities that are contained in our ideas of bodies refer to anything true or
real, and the argument only allows us to infer that the cause must formally
contain all the reality that is represented in our ideas. Of course, this is not
to deny that bodies might on occasion be extended in just the ways they are
represented as being in our ideas, or even that bodies may have colours and
other sensible qualities. Descartes’s point was
just that the argument is not strong enough to allow us to draw these further
conclusions. ESSAY QUESTIONS AND RESEARCH PROJECTS
1. Is
Descartes entitled to affirm the separability principle? That is, from the fact that I can clearly
and distinctly perceive one thing without another, does it have to follow
that the one thing must be capable of existing apart from one another?
2. Has
Descartes made a convincing case for the claim that minds could exist apart
from bodies and that thought and feeling do not have to involve any operation
of an extended thing?
3. According
to Descartes, I can be sure that external objects exist because I find in
myself a strong inclination to suppose that my ideas of sense are caused by
such objects, and God would be a deceiver for giving me such an inclination
were there no such objects in existence. But, by the same token, I find in
myself a strong inclination to suppose that bodies possess colour and other
sensible qualities. Yet Descartes
appears not to have wanted to conclude that external objects must therefore
be coloured and possessed of the other sensible qualities. How can this
be? Is Descartes’s
position on the demonstrability of the existence of extended objects but the undemonstrability of the existence of coloured objects
consistent? If so, say why. If not, say why not. |