Think: A Compelling Introduction to Philosophy by Simon Blackburn

be goes dim. We could
regain it, if we could argue that the scenarios are either impossible,
or at least have no real chance of being the way things are.The difficulty is that it is hard to show them to be impossible, and in these
abstract realms we have no very good sense of probabilities or
chances. So it is difficult to argue that they have no chance of being
true without relying on the very opinions that they query. Hence,
scepticism permanently beckons, or threatens, us. We may be
tracking the world reliably, but we may not. To revert to the engineering analogy I used in the Introduction, the structure of our
thought seems to span large gaps: here, the gap between how things
appear and how they might be. We hand ourselves the right to cross
those gaps. But if we (1o this trailing no very good sense of our own
reliability or harmony with the truth, then that right seems illfounded. And this is what the sceptic insists upon. Any confidence
in a harmony between the way we take things to be, and the way
they are, will seem to be a pure act of faith.

    Descartes left us with a problem of knowledge. He also left us
with severe problems in understanding the place of our minds in
nature. And finally the entire scientific revolution of which he was
such a distinguished parent left us with profound problems of understanding the world in which we are placed. We have seen something of the problem of knowledge. The next chapter turns to
problems of mind.

     

CHAPTER TWO
Mind
    SUPPOSE WE PUT ON ONE SIDE the general problem of harmony
between the way we take the world to be and the way the world is.
We shall keep our fingers crossed, supposing that we do really
know what we naturally take ourselves to know. But how well do
our views hang together? Descartes left us with our own selves and
our own minds as special, intimate, objects of immediate knowledge. Or rather, each of us is left with his or her own mind as a special, intimate, object of immediate knowledge. For even if I can
climb out of the seas of doubt onto the Cogito, I cannot climb out
onto the nature of your mind. So how then do I know anything
about your mental life? How do I know, for instance, that you see
the colour blue the way that I do? Might it be that some of us feel
pain more, but make less fuss about it, or that others feel pain less,
but make more fuss? How do we begin to think about mind and
body, brains and behaviour?

    THE GHOST IN THE MACHINE
    We have seen how Descartes's strategy led him to regard knowledge of our own minds as more secure and certain than knowledge
of the rest of the world. But Descartes was also a scientist. He made
foundational discoveries in optics. He practised dissections, and
knew a fair amount about the transmission of impulses through
the nerves to the brain. He knew this took place by means of a physical transmission, a 'pull' or `violent motion' of the nerves, or as
we would now think, an electrochemical impulse transmitted
through the nervous system. The ordinary senses of sight, touch,
taste, smell, and hearing activate the nervous system, which transmits messages to the brain. The brain is not, of course, an undifferentiated lump. Bits of the brain transmit signals to other parts of
the brain and back to the body: whole patterns of activation get set
up. All this is part of neurophysiology. These events can in principle be seen in public: with the right instruments, the patterns of
activation can he shown to a classroom.
    And then what?
    Well, then there is the magic moment. The'mind' (the thinking
thing, or'res cogitans') gets affected as well, and the whole world of
experience opens up. The subject sees colours, hears sounds, feels
textures and temperatures, and has sensations of taste and smell.
This world of experience is composed of mental events or events
within subjective consciousness. These events in the subject's consciousness cannot he seen in public. They are private. The