Hi Kevin

I must admit to some surprise.

Are you really suggesting that there is really no qualitative difference between human and animal consciousness? If that were so, at what point would this 'general type of consciousness', as you call it, disappear?  Does a worm have it? An amoeba?

Actually, the use of the term 'consciousness' with respect to animals seems very questionable to me. You say 'We focus on humans because we're each certain that at least one human possesses consciousness (ourselves)'.  OK.  But what really authorizes us, as philosophers, to use the same term, 'consciousness', with respect to animals? Might we not simply be projecting? (anthropomorphizing.) The same way we do when we say in casual conversation 'This dog thinks I am going to feed him' Or 'This cat is hoping I will stroke it.'  That is, assuming an animal does what we do when we 'think' or hope', etc.

Getting back to the topic of zombies which began this thread, an intriguing idea occurs to me. David Chalmers says that it is not necessary to know what consciousness means to conceive of a zombie (which is a human minus consciousness). I think that position is obviously untenable, as I have said. But if he is correct, and if as you say Chalmers' concern is not with 'a type of consciousness that is necessarily human-specific', then would that mean that a zombie plus a cat's consciousness (say) would equal a human being? I'm not sure he could say no, given that he does not believe it necessary to have any particular definition of consciousness when talking about zombies.

Regarding your question: 'After all, why should we be concerned with the traits unique to humans unless we were concerned with something we thought to be necessarily connected to a particular type of physical structure?', the answer to that seems to me very simple. Do we, or do we not, think that one of the central purposes of philosophy is to tell us something important about what it means to be human? If the answer is no, I personally would lose all interest in it straight away. And I think huge areas of it, including most of its leading figures, would have to be jettisoned as entirely without value.