Scrutiny of the Two-Dimensional Argument against Physicalism

Chalmers’s two-dimensional argument against materialism (aka the zombie argument) is arguably the most ingenious attempt to ground a view about fundamental reality on epistemic considerations. From the conceivability of a being that is physically identical to a conscious being but that is deprived of phenomenal consciousness (a zombie), the argument draws on the interplay of the primary and the second intensions of the zombie hypothesis to infer the metaphysical possibility of a zombie world, and thus the falsity of physicalism about phenomenality. By means of a detailed reconstruction of the two-dimensional argument, the paper tries to isolate its most central assumption: that the role played by an epistemic scenario (an intentional object) in the verification of the zombie hypothesis is played by a nonintentionally individuated metaphysical world (the zombie world) considered as actual. The paper argues that no non-viciously circular case for this assumption has been made. Thus, the two-dimensional argument is at best inconclusive.