clipped from zombiepataphysics.blogspot.com

The p-Zombie is a philosophical construct mainly attributed to David Chalmers, and used by times in debates about consciousness studies, to which your blogger has occasionally contributed. Briefly, the argument I think goes like this:
Imagine an entity indistinguishably different from a human being. It looks like one, walks and talks like one, reacts like one - there is no way of telling it's not a human. But it's not, it's a Zombie, without "qualia" or real human consciousness. The argument, to simplify, says that if you can imagine such a being, then you accept that the essence of human consciousness, perhaps the mind or "soul", is NOT a product of the biological machine, but something else.