Once again, I've pulled part of Camilo's comment up into an entry of its own, so it doesn't get overlooked:
Although there is no logical link between the possibility of Zombiehood, and concluding that if a Zombie can exist, then the rest of humanity must be a Zombie as well.
I think the link is pretty direct, as I'll try to explain.
If you're a physicalist, who believes that mind is just something that happens with the right configuration of matter, then according to your (physicalist) theory the fact that you can observe things exhibiting the appropriate behavior and having the appropriate physical structure counts as evidence that those things have minds1. So there's lots of evidence for other minds.
But if you believe in the possibility of Zombiehood, then explicitly what you disbelieve is that any of that stuff counts as evidence of minds. But if that's the case, what possible reason do you have for supposing that there are any minds except the one and only case for which you do have observations of the type that you think count? It seems to me not at all kosher to help yourself to physicalist intuitions to kick-start a supposition that other minds are a possibility, let alone a probability, while strongly denying the possibility of empirical evidence of the existence of another mind in any specific candidate for Zombiehood. A person who thinks that Zombiehood is at all a live possibility owes some kind of explanation of why the existence of other minds is more than a bare logical possibility, the way other invisible intangible metaphysical entities such as malevolent senses-fooling demons are, and particularly why the rest of humanity is a better candidate than, say, rocks, clouds, glasses of water, or sunlight.
[1] I'm using have a mind to mean experiencing qualia
Posted by joshua at April 4, 2005 08:42 AMWell, I have to tell you that in principle, I agree with most of the things you are saying. The only thing I don't agree with is the approach that you take to Zombiehood. I'll explain why.
I think that the argument of Zombiehood, as stated by most scientists and philosophers using it, is not aimed at proving the existence of Zombies, but at stating an ‘explanatory gap’ in our materialistic account of the universe. Of course, you can always brush off the problem by saying (what I take your argument is) that;
“If we have this structure and this behavior, and we have qualitative states of consciousness, then it follows that our structure and behavior HAVE to be associated with qualitative experience. So there is nothing left to explain”
Or in other words;
“If it is this way, then it HAS to be this way, and there is nothing else left to explain”.
For most of us, this is highly unsatisfactory as an answer. That’s why the Zombie argument is illustrative of the problem we are facing. Not because we believe in Zombies (so we don’t need to prove their existence, nor build an epistemological/metaphysical theory around them) but because we believe there is SOMETHING we need to explain (maybe there is not, as Dennett proposes).