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Topic: Mind
Why the word "physicalism" anyway? Apprently the move to talk about "physicalism" rather than "materialism" (SEP) is rooted in the need to distinguish between the basic position of monism, in this case what the kind science today or in the future should be able to explain by reference to "things", from other kinds of materialism. Of course, what constitutes physicalism or even the various suggested kinds of physicalism is debatable but for those of us just getting our feet wet, there are three main distinctions.
The strongest thesis of physicalism is Type Physicalism, usually associated with identity theory. For every type of mental event, there must be a type of physical event. The familiar pain = 'C fibre' event holds here. I noted a few days ago that this thesis is probably too strong because of the fact that it's difficult to talk about an animal being in pain that has different neurological structures than a human (multiple realizibility).
Supervenience Physicalism is in the middle - actually, it's a little bit of a different way of talking about physicalism. SP is usually considered "minimal" physicalism, or the very weakest thesis that can qualify as physicalism. SP asserts that all mental properties necessarily change with an underlying change in the physical, and vice versa. Hence, as discussed in an earlier post, we can't define a zombie with 1-1 physical correspondence that has any kind of a different mental life. Mental properties must pace physical properties. Type physicalism guarantees supervenience.
Finally, there is token physicalism which says that for every actual instance of something, there must be a physical something. Property dualists are token physicalists. The mind can't exist without the brain, but mental properties can change independent of it - that is, the mental doesn't supervene on the physical. Because dualism is permitted, TP can't be considered minimal physicalism. So for instance, David Chalmers who is a property dualist argues that physicalism is false, and that's perfectly consistent with token physicalism. Functionalists are also token physicalists. Whether or not functionalism meets the criteria for minimal physicalism as defined by supervenience is debatable.
Type/token relate to each other also in the following way. A type is like a dollar. A token is like a particular dollar bill, or a quarter. A token physicalist can get a dollar by a couple of quarters and fifty pennies. Maybe a gold standard analogy applies here. A type physicalist will define a dollar as x amount of gold. A paper dollar or four quarters are worthless, or at least they ultimately aren't actually a dollar.
