This paper presents a reconstruction of the argument for the logical possibility of zombies, proposed by David Chalmers, which has been debated in analytical philosophy for at least fifteen years now. Beside discussing it, I’m trying to analyze every of its premises. My aim is, especially, to present how the reasoning can show that: (a) zombies/zombie worlds are genuinely conceivable; (b) conceivability is a good guide to possibility; (c) the possibility of zombies is philosophically significant. I’m particularly putting emphasis on (...) some issues concerning two-dimensional semantics and distinctions of conceivability. The conclusion of this paper is that the argument is still not refuted, so a discussion over it should be conducted, instead of a priori refutation. The debate over zombies may have a positive influence on many fields of philosophical investigation. (shrink)