Think: A Compelling Introduction to Philosophy (5 page)

It is important to seize on two things at the outset. First,
Descartes is perfectly well aware that as active, living, human agents we do not bother ourselves about such an outlandish possibility. In fact, we cannot: as many philosophers have pointed out, it
is psychologically impossible to keep doubt about the external
world alive outside the study. But that does not matter.'I'he doubt
is worth bothering about because of the task he is engaged upon.
This is the task of finding foundations of knowledge, of ensuring
that his beliefs are built on a sound footing. Descartes's inquiry is
made for purely intellectual reasons. Second, Descartes is not asking you to believe in the possibility of the Evil Denton. He is only
asking you to consider it-en route to getting clear how to dismiss
it. That is, he thinks (not unreasonably, surely?) that unless this
possibility can be dismissed, there remains a challenge of scepticism: the possibility that we have no knowledge, but that all our heliefs are entirely delusive.

We can appreciate the thought-experiment by reminding ourselves how very `realistic' a virtual reality can become. Here is an
updated variant of the thought-experiment. Imagine an advance
in science that enables a mad scientist to extract your brain, and
then to maintain it in a vat of chemicals that sustain its normal
functioning. Imagine that the scientist can deliver inputs to the
normal information channels (the optic nerve, the nerves that
transmit sensations of hearing and touch and taste). Being goodnatured, the scientist gives information as if the brain were lodged
in a normal body and living a reasonable life: eating, playing golf,
or watching TV. There would be feedback, so that for instance if
you deliver an `output' equivalent to raising your hand, you get
`feedback' as if your hand had risen. The scientist has put you into
a virtual reality, so your virtual hand rises. And, it seems, you would have no way of knowing that this had happened, since to
you it would seem just as if a normal life was continuing.

Descartes's own version of the thought-experiment does not
cite brains and vats. In fact, if you think about it, you will see that
he does not need to do so. Our beliefs about the brain and its role
in generating conscious experience are beliefs about the way the
world works. So perhaps they too are the result of the Evil Demon's
inputtings! Perhaps the Demon did not need to get his hands (?)
dirty messing around in vats. He just inputs experiences in whatever way is made appropriate by the real reality. Brains and nerves
themselves belong to the virtual reality.

This thought-experiment does not cite actual illusions of sense,
or actual dreams. It simply sets experience as a whole against a very
different and potentially disturbing reality. Notice as well that it is
not obviously useful to argue against the Evil Demon hypothesis
by citing the coherence and scale of everyday experience. For we do
not know of any reason why the Demon could not input experience as coherent as he wishes, and of whatever scale or extent he
wishes.

So how could we possibly rule out the Evil Demon hypothesis?
Once it is raised, we seem to be powerless against it.

Yet, in this sea of doubt, just when things are at their darkest,
Descartes finds one certain rock upon which he can perch.'Cogito,
ergo sum': I think, therefore I am. (A better translation is `I am
thinking, therefore I am'. I)escartes's premise is not `I think' in the
sense of `l ski', which can be true even if you are not at the moment
skiing. It is supposed to be parallel to `I am skiing.)

Even if it is a virtual reality that I experience, still, it is I who experience it! And, apparently I know that it is I who have these experiences or thoughts (for Descartes, `thinking' includes 'experiencing').

Why does this certainty remain? Look at it from the Demon's
point of view. His project was to deceive me about everything. But
it is not logically possible for him to deceive one into thinking that I
exist when I do not. The Demon cannot simultaneously make both
these things true:

I think that I exist.

I am wrong about whether I do.

Because if the first is true, then I exist to do the thinking. Therefore,
I must be right about whether I exist. So long as I think that (or
even think that I think it), then I exist.

I can think that I am skiing when I am not, for I may be dreaming, or deluded by the Demon. However, I cannot think that I am
thinking when I am not. For in this case (and only this case) the
mere fact that I think that I am thinking guarantees that lam thinking. It is itself an example of thinking.

THE ELUSIVE `I'

Outside the context of the doubt, the `I' that thinks is a person that
can be described in various ways. In my case, I am a middle-aged
professor of philosophy, with a certain personality, a history, a network of social relations, a family, and so on. But in the context of
the doubt, all this is swept away: part of the virtual reality. So what is the `I' that is left? It seems very shadowy-a pure subject of
thought. It might not even have a body! This takes us to the next
twist.

You might try peering into your own mind, as it were, to catch
the essential `you'. But, remembering that the `you' (or the `I , from
your point of view) is here separated from normal marks of identity (your position in space, your body, your social relations, your
history), it seems there is nothing to catch. You can become aware of
your own experiences, but never, it seems, aware of the `I'that is the
subject of those experiences. Or you can try to imagine the self, to
frame a picture of it, as it were. But as Descartes remarks, imagination seems good at framing pictures of things that have shape and
size, and are found in space ('extended things'). The self that remains as the rock in the seas of doubt may not be an extended
thing. For we can he certain of it when we are still uncertain about
extended things, since we are taking seriously the possibility of the
Evil Demon.

One reconstruction of this point of the argument presents
Descartes thinking like this:

I cannot doubt that I exist. I can doubt whether things extended in space ('bodies') exist. Therefore, I am not a body.

In a nutshell, souls are certain, bodies are doubtful, so the soul is
distinct from the body. If this is Descartes's argument, then it is superficially plausible, but can be seen to be invalid. For consider the
parallel:

I cannot doubt that I am here in the room. I can doubt
whether a person who will get bad news tomorrow is in the room. Therefore, I am not a person who will get bad news
tomorrow.

A nice proof with a welcome result! The fallacy is often called the
`masked man fallacy': I know who my father is; I do not know who
the masked man is; so, my father is not the masked man.

I myself doubt if Descartes committed this fallacy, at least in this
Meditation. At this point he is more concerned with the way in
which we know anything about souls and bodies. He is not concerned to prove that they are distinct, but more concerned to show
that knowledge of the self is not dependent upon knowledge of
bodies. Because the one can be certain, even when the other is not.
Nevertheless, what are we left really knowing about the self?

In the following century the German philosopher Georg
Christoph Lichtenberg (1742-99) remarked: `We should say, "it
thinks" just as we say, "it thunders"Even to say "cogito" is too
much, if we translate it with "I think".' (Lichtenberg liked pithy
aphorisms, and was an important influence on a yet later figure,
Friedrich Nietzsche [1844-19001.)

The idea is that the apparent reference to an'1' as a `thing' or subject of thought is itself an illusion. There is no 'it'that thunders: we
could say instead just that thunder is going on. Similarly Lichtenberg is suggesting, at least in the context of the doubt, that
Descartes is not entitled to an `1' that is thinking. All he can properly claim is that `there is a thought going on'.

This seems a very bizarre claim. For surely there cannot be a
thought without someone thinking it? You cannot have thoughts
floating round a room waiting, as it were, for someone to catch them, any more than you can have dents floating around waiting to
latch onto a surface to be dented. We return to this in Chapter 4.
But then why isn't Lichtenberg right? If Descartes cannot confront
a self that is doing the thinking, cannot experience it, cannot imagine it, then why is he entitled to any kind of certainty that it exists?
Indeed, what can it mean to say that it exists?

Descartes adroitly puts this problem to one side, by raising a
parallel difficulty about `things which people commonly think
they understand most distinctly of all'-ordinary bodies, or things
met with in space. This is what was aimed at by the ball of wax example. Here is a possible reconstruction of the argument:

At a particular time, my senses inform me of a shape,
colour, hardness, taste that belong to the wax. But at another time my senses inform me of a different shape etc. belonging to the wax. My senses show me nothing but these
diverse qualities (which we can call `sensory qualities, since
our senses take them in). I nevertheless make a judgement
of identity: it is the same piece of wax on the earlier and the
later occasion. So, it is the nature of the ball of wax that it
can possess different sensory qualities at different times.
So, to understand what the wax is I must use my understanding, not my senses.

If this is a good reconstruction, we should notice that Descartes is
not denying that it is by means of the senses that I know that the
wax is there in the first place (assuming we have got rid of the Evil
Demon, and are back to trusting our senses). In fact, he goes on to
say as much. Rather, he is suggesting that the senses are like messengers that deliver information that needs interpreting. And this interpretation, which is here a question of identifying the one object amongst the many successive appearances, is the work of the
understanding. It is a matter of employing principles of classification, or categories, whose credentials we can also investigate.

So, all we can understand by the wax is that it is some elusive
thing' that can take on different bodily properties, such as shape,
size, colour, taste. And we understand by the self, the `I , just some
equally elusive `thing' that at different times thinks different
thoughts. So maybe the self should not he regarded as especially
mysterious, compared with everyday things like the ball of wax.
Perhaps selves are no harder to understand than bodies, and we
only think otherwise because of some kind of prejudice. We return
to the wax in Chapter 7.

CLEAR AND DISTINCT IDEAS

The first two Meditations deserve their place as classics of philosophy. They combine depth, imagination, and rigour, to an extent
that has very seldom been paralleled. So one is left with bated
breath, waiting for the story to unfold. Here is Descartes left perching on his one minute rock, surrounded by a sea of doubt. But it
seems he has denied himself any way of getting off it. Life may still
be a dream. To use the metaphor of foundations: he is down to
bedrock, but has no building materials. For the very standards he
set himself, of`demon-proof' knowledge, seem to forbid him even
from using`self-evident' or natural means of reasoning, in order to
argue that he knows more than the Cogito. There is nothing diffi cult about the Demon deceiving us into listening to delusive pieces
of reasoning. Our reasonings are apt to be even more fallible than
our senses.

Curiously, he does not see it quite like that. What he does is to reflect on the Cogito, and ask what makes it so especially certain. He
convinces himself that it is because he has an especially transparent
`clear and distinct' perception of its truth. It is generally agreed that
Descartes, the mathematician, had a mathematical model of clarity in mind. Suppose, for instance, you think about a circle. Imagine a diameter, and draw chords from the opposite ends to a point
on the circumference. They meet at a right angle. Draw others, and
they always seem to do so. At this point, you might have a not very
clear sense that perhaps there is a reason for this. But now, suppose
you go through a proof (drawing the line from the centre of the circle to the apex of the triangle, and solving the two triangles you create). After that you can just see that the theorem has to hold. This
may come as a'flash': a blinding certainty, or insight into this particular piece of geometrical truth. This is just a random geometrical example of a procedure that can make you `see' something that
you might only dimly have grasped. But if only we could see the
rest of reality, mind, body, God, freedom, human life, with the
same rush of clarity and understanding! Well, one philosophical
ideal is that we can. This is the ideal of rationalism: the power of
pure unaided reason. For the rationalist can see from her armchair
that things must he one way and cannot be other ways, like the
angle in the semicircle. Knowledge achieved by this kind of rational insight is known as `a priori': it can be seen to be true immediately, without any experience of the way of the world.