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Metaphysics of the 'self'
Descartes: dualism (260-62)
Dualism is the thesis that there are two basic substances (things with properties that are not themselves properties.) For Descartes, these are mind and body. Mind has the fundamental property of thought, while body does not. Body has the fundamental property of "extension" (extended in space) while mind does not. Here is one of his arguments for dualism:
  1. Body is divisible (because it takes up space)
  2. Mind is not divisible
  3. Things with differing fundamental properties must be distinct kinds of things
  4. Therefore, mind and body are truly distinct substances
Can you see any problems with this argument?
Apart from problems with Descartes' argument, there is also the problem of the interaction of the two substances. How can a substance which is not physical (mind) interact with one that is? And how can one that is not 'mental' interact with one that is? Descartes notes that our bodies cause things to happen in our minds (e.g. sense percetions) and that our minds seem to cause things to happen in our bodies (e.g. voluntary movements.) But all this struck many philosophers (and still does) as mysterious. What could the causl linkage possibly be? This led many to endorse differing metaphysical views, such as idealism or materialism.
A materialist and a determinist. See glossary, and pg. 243.
  • materialism: all reality is "matter in motion" - that is, only physical things are real (see the film clip on Hobbes for his argument here.)
  • determinism: all events, including human decisions and actions, are uniquely determined by other events (other motions in bodies.) In other words, free will is an illusion; all our decisions are actually 'forced' by the configurations of desires and dislikes, etc. within our psychologies. (Actually all are responses to the prospects of pleasure or pain, according to Hobbes.) For Descartes, dualism meant that decisions (which are mental items) did not happen 'mechanically,' as events in the physical world do. Therefore, he thought we have free will (and that it is possible that the soul is immortal.) For Hobbes, dualism is wrong, and so the thesis of free will is also.  
So how does he explain the phenomenon of deliberation? (This also could explain how we change our minds - see pg. 243.)
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