Natural selection has ensured that each species achieves the requisite effect somehow, but it doesn't care, so to speak, how the trick is done.

Kripke says that physicalists like me can't explain the 'apparent contingency' of mind-brain identities. He maintains that, if I really believed that pains are C-fibres, then I ought no longer to have any room for the thought that 'they' might come apart. His argument is that, since pains aren't identified via some contingent description, but in terms of how they feel, I have no good way of constructing a possible world, so to speak, where C-fibres are present yet pains absent.

I realize that I won't have quite enough time to understand everything - but that hasn't stopped me wanting to understand as much as I can.

The use of neuroscientific data to help resolve phenomenological questions is proving a common theme in much contemporary thinking about the mind. How rich are the contents of visual perception? Does vision only tell us about shapes and colours, or does it also represent higher categories like lemon or umbrella?

There is a brain mechanism that works to identify colour differences directly, without first identifying the absolute colour of each surface. So on my view there is no reason to suppose anything like ten million colour responses to surface viewed singly.

If there is such a simple argument for physicalism, how come everybody hasn't always been a physicalist? That's a good question, and there is a good answer. The 'causal completeness of physics' wasn't widely accepted until recently.

A certain kind of methodologically-minded philosopher of science is quick to read off metaphysical conclusions from features of scientific practice. Chemists don't derive their laws from fundamental physics, so reductive physicalism must be false. Biologists refer to natural numbers in some of their explanations, so numbers must exist. I think that this kind of thing makes for bad philosophy.