Think: A Compelling Introduction to Philosophy Read Online Free PDF Page 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