Abstract

David Chalmers argues that zombies are possible because they are ideally conceivable and that therefore consciousness does not supervene on the physical. In this paper I discuss the most influential criticism of the conceivability-possibility principle in the current literature. According to that criticism, the conceivability-possibility principle is unjustified because it depends on a certain unjustified assumption concerning the semantic conditions under which necessary statements can be true a posteriori, namely that a posteriority is due to contingency at the reference-fixing level, so that a necessary statement can be true a posteriori only if at least one of the concepts flanking the identity sign refers contingently.