But 'life' can clearly be analysed in functional and structural terms. There is no sense to be given to the notion of something that is functionally and structurally indiscernible from a duck, having all the same kinds of relations to other objects as another duck does, and yet somehow fails to really be a living duck. To be a living duck just is to have the right kinds of functional relations and so forth. There's nothing more to it than that.Here, Richard almost talks as if the problem with the vitalism analogy is that the argument for vitalism is wrong. But the key thing is why it's wrong. It's wrong because we have good reason to reject our the pre-theoretical intuitions about the nature of life that some people have in a powerful form. Spend enough time around creationists, and soon you realize that many of them have an intuition that life is non-physical, so it would be impossible in principle for unguided matter to give rise to life. Sounds stupid? That's the point. We often mistake stupid ideas for profound philosophical insights.
Richard says life can be analyzed in functional terms (patterns of causal relations and such). I agree. But this isn't obvious, built into our pre-theoretical intuitions, or any such similar thing. If you want to analyze life functionally, you admit our intuitions about these things don't always give us the right answer. Conversely, some people think consciousness should be analyzed in functional terms. If they're correct, then consciousness is once again in the same boat as life.
Perhaps you dislike whatever theory happens to be the currently reigning functional analysis of consciousness. Perhaps you do so with reason. Still, we're in the beginning stages of understanding the brain. It's a false dilemma to say "either we have the right answer to this key issue already, or we have to accept our intuitions and not take seriously the possibility of ever getting another answer."
The burden of proof is on anyone who thinks there could be no physicalist account of consciousness. In my last post, I suggested there might be a good argument for that conclusion. But if there were, the dualist wouldn't need a zombie horde to do his dirty work. Invoking zombies is a weird way around this--it assumes we have reason to think consciousness isn't physical without ever providing the reason.
Richard has also recently written a post challenging the idea that thought experiments are question-begging. On this point, he brings in the analogy with the common sense belief that the Pope doesn't count as a bachelor. There's a disanalogy here, though: we're in a reasonably good position to answer that question based on our experience with how the term is used. In the zombie case, I don't know how we could know such things are possibit's mainly a question of what convinces people, but his interactions with Eliezer Yudkowsky suggested he thought many people who aren't convinced should be.
The most frustrating post on the zombie argument, though, has to be how to imagine zombies. There, Richard suggests that a world microphysically identical to ours would contain things like David Chalmers' book The Conscious Mind. This is a claim that should sound a caution in any good dualist's mind: if there is non-physical consciousness, it seems plausible to think that it affects the physical world, and most importantly is the reason philosophers like Chalmers write books like The Conscious Mind. The view that consciousness exists but has no such causal powers is known as epiphenomenalism, and is quite popular today. Chalmers endorses it. But Chalmers admits he isn't entirely confident about it. Now: if even a big-shot dualist like Chalmers isn't entirely confident about the truth of epiphenomenalism, what business do we have simply intuiting claims that presuppose its truth? Richard talks about what a super-genius would calculate, but the conclusions of super-geniuses seem an even poorer candidate for intuiting than most metaphysical issues (why bother with smart people if they can be replaced by intuitions?)* If nothing else shows the doubtful, question-begging nature of the zombie argument, this point should.
For more on this issue, I strongly recommend Siris' "Zombie Invasion" round-up. Especially the links there to the Brood Comb posts on epiphenomenalism. Oh, and be sure to check this out.
*As an aside: it matters a bit whether Richard means to say that the super-genius will know everything about a snap-shot of a world, or about it's causal processes and future as well. But it seems that "all there is to know" includes these things.