From Philip Goff's TLS review of Robert Kirk's new book.
A philosophical zombie, as opposed to its undead namesake, is an atom-for-atom physical duplicate of a human being ... which lacks any kind of conscious experience. If you put a knife in it, it will scream and try to escape. If you give it a cup of tea, it will thanks you politely and sip it with a smile. It can do your job and chat to your colleagues as cleverly or as ineptly as you yourself can. And yet there is nothing that it is like to be your zombie twin. Its screams are not accompanied by the feeling of pain. Its tea drinking is not accompanied by the taste of tea, or the feeling of warmth and pleasure. It does not have any sensory experience of the three-dimensional world with which it interacts so well. The lights are on but nobody is at home.Yes, I've also been to one too many philosophy seminars.
Nobody thinks zombies are real, but some philosophers - a sizeable minority - think that zombies are possible.