Meta Ontology

In this paper I challenge the core of David Chalmers' argument against materialism-the claim that "there is a logically possible world physically identical to ours, in which the positive facts about consciousness do not hold." First, I analyze the move from conceivability to logical possibility. Following George Seddon, I consider the case of a floating iron bar and argue that even this seemingly conceivable event has implicit logical contradictions in its description. I then show that the distinctions Chalmers employs between primary and secondary intensions, and a priori and a posteriori entailment, break down upon close examination-with iron bars and with consciousness it is impossible to know where primary intensions end and secondary intensions begin. I extend this analysis of logical possibility to the famous zombie thought experiment and conclude not that a zombie world is logically impossible, but rather that, at present, the question is open. Finally, I show how a similar line of argument may be used to undermine the "Mary the color scientist" thought experiment as well.