[hugh_]

E.g., are we right to assume that all the laws of chemistry are "in principle" reducible to physics, even though we can never hope to make such a reduction in practice?

Actually, making that reduction in practice is pretty much what I do for a living.

[foldr]

Yes, I'm not suggesting that there's a complete disconnect between physics and chemistry, but we're a long way from having a complete understanding of how all chemical reactions work at the physical level. That is, an actual proof that all known laws of chemistry are mathematical consequences of the laws of physics (without making too many fudges, simplifying approximations, etc. etc.)

This is not in any way intended as a criticism of physicists or chemists, in case it comes across like that. They're both incredibly successful at what they do.

Just googling around, this paper gives quite a nice overview of what sensible scepticism about the possibility of reduction looks like: http://www.springerlink.com/content/v05g613468p6xk17/