Click through for full sized version, and philosophical explanation if you’re not familiar with David Chalmer’s and Daniel Dennett’s positions on philosophical zombies.
I can’t say I’ve ever been too impressed with the idea of a philosophical zombie. I could see maybe a zombie existing that behaves identically to a human being, but whose internals are simply designed to fool people.
But the classic concept is a zombie that is identical to a human being in every way, right down the neurological structure of the brain, but isn’t conscious. In my mind, that concept only makes sense within the framework of substance dualism, of belief in a non-material soul. If you have that belief, then the philosophical zombie is a meaningful concept to you. If you don’t have that belief, then I can’t see how the concept has any coherence.
Perhaps the silliest part of the concept is the idea that, because we can conceive of it, it must exist. Well, I can conceive of dragons, poltergeists, and perpetual motion machines, but I feel pretty comfortable that none of those things exist. I think the entire history of humanity demonstrates beyond all question that we can conceive of all kinds of impossible things.