rees that the notion of metaphysical identity can save materialism, and he spends much of Chapter 2 and the entire section Objections from a posteriori necessity in Chapter 4 arguing against such a materialist approach. Before Chalmers begins to develop his own dualistic theory, he argues that materialism must hold that consciousness is logically supervenient on the physical; that materialists cannot appeal to metaphysical supervenience as a way of avoiding the problems he raises with logical supervenience; and that therefore, materialism fails. In this paper, I will first discuss Chalmers' arguments against the logical supervenience of consciousness before turning to his arguments against the metaphysical supervenience of consciousness which I believe to be wrong. In The Conscious Mind, Chalmers' first argument against the logical supervenience of consciousness stems from the logical possibility of "zombies." A zombie, in the philosophical literature, is supposed to be a being just like a person in all respects (behavior, language ability, appearance, possession of beliefs and desires) except that it lacks all consciousness.(2) Chalmers imagines his zombie twin, a being physically identical to him who lives on a twin Earth that has an environment physically identical to ours. Chalmers' zombie twin looks and acts just like the real Chalmers does in our world, but he does not have any of the phenomenal experiences that the real David Chalmers has. This imaginative exercise is meant to show that zombies are logically possible creatures, and Chalmers argues that the logical possibility of zombies proves that materialism is false. His argument can be summarized as the following premises: (1) Consciousness exists in our world; this is an empirical claim. (2) Because zombies are logically possible, consciousness cannot logically supervene on the physical. If consciousness does not logically supervene on the physical, then one cannot reduce fa...
