The Irreducibility of Consciousness

In this paper, by analyzing the Chalmers-Searle debate about Chalmers’ zombie thought experiment, I attempt to determine the implications that the irreducibility of consciousness has for the truth of materialism. While Chalmers claims that the irreducibility of consciousness forces us to embrace dualism, Searle claims that it has no deep metaphysical im­ port and, in particular, that it is fully consistent with his materialist the­ ory of mind. I argue that this disagreement hinges on the notion of physi­ cal identity in play in the discussion. Clarifying this notion in turn helps to clarify what it means to claim that consciousness is irreducible, and provides insight into the implications that the truth of this claim would have for the dualism-materialism debate. Ultimately, I suggest that the sort of irreducibility that can be motivated by the zombie thought ex­ periment is not sufficient to require the rejection of materialism. The question of whether there can be a physical reduction of con­ sciousness once seemed to rest largely on the plausibility of two nowfamiliar thought experiments — Frank Jackson’s Mary, the color scientist, and Thomas Nagel’s bat. More recently, the focus of the irreducibility debate has shifted to David Chalmers’ thought experi­ ment about zombies, creatures who are physically indiscernible from humans but phenomenologically void. Confronted with this thought experiment, the materialist has appeared to have three options. She can reject the claim that zombies are conceivable, she can reject the claim that that the conceivability of zombies entails their possibility, or she can reject the claim that the possibility of zombies entails the irreducibility of consciousness. It has been generally assumed, how­ ever, that to accept all three of these claims — and thereby to accept the irreducibility of consciousness — would be to admit defeat. In this paper, I want to examine the merits of this assumption that the irreducibility of consciousness is incompatible with materialism. I will come to this issue by way of John Searle’s criticism of Chalmers’ thought experiment. Both Chalmers and Searle are proponents of the irreducibility of consciousness, but, interestingly, they disagree about Disputatio,Vol. I, No. 19, November 2005