Why the Zombie Conceivability Argument Is Unsound

Perhaps the currently most popular and discussed objection to physicalism is the zombie conceivability argument, whose most famous proponent is David Chalmers. In a nutshell, the argument goes as follows: zombies are conceivable, if zombies are conceivable then zombies are possible, and if zombies are possible, then physicalism is false; therefore, physicalism is false. Replies to this argument by physicalists have focused on the first two steps: they either deny that zombies are conceivable or that conceivability entails possibility. In response to these replies, Chalmers has recently elaborated in great detail the notions of conceivability and possibility that he thinks are at stake, and argued forcefully and skillfully that in the relevant senses of conceivability and possibility, the zombie conceivability argument stands.

I am unsatisfied with the structure of this dialectic. Although I am sympathetic to both standard responses to the zombie conceivability argument, I think they are not decisive, because they are open to Chalmers’ sophisticated rebuttals. I think it might be more promising, and it would at least be useful, to scrutinize more carefully the last step in the argument. This step requires assumptions about how physicalism should be formulated as well as which possible worlds are accessible (in the sense of possible world semantics) from the actual world. It we pay careful attention to the notion of accessibility between possible worlds and formulate physicalism in a way that doesn’t beg the question, I believe we can show that even granting the first two steps of the zombie conceivability argument, the falsity of physicalism doesn’t follow. Or if zombie-philes should insist that it does, then we can construct arguments fully analogous to the zombie conceivability argument to the effect that physicalism is true.

I am going to present an exploratory version of the above at Tucson VII – Toward a Science of Consciousness 2006. My talk is on Tuesday, April 4, afternoon.

One comment

  1. wmr

    Maybe it’s because I’m a complete amateur at philosophy, but zombies just don’t do a thing for me. I think I can best illustrate my problem with the idea by considering a different sort of case: Pegasus.

    I want to imagine a flying horse, so I add bird’s wings, scaled up to the size of a horse, to a typical horse. Voila, flying horse. But this totally ignores such considerations as: Where are the muscles which will power the wings? Where are the nerves to those muscles and the brain space to control it all? What about the bones? Can a horse fly with solid horse bones? Can it run with hollow bird bones? Will the aerodynamic properties of a bird’s wing be preserved by simply making them big enough to look right to me?

    Similarly, simply saying “well, let’s imagine a person without consciousness who acts like everybody else” ignores the consideration that consciousness may be connected to other brainmind functions in ways we are unaware of. If this were a thought experiment leading to psychological experiments, that would be one thing. But as a basis for armchair speculation, I consider it a waste of time.

    I came here via Leiter and I chose you to inflict my uninformed speculations on because you have so few comments that I thought there would be a better chance of getting an answer that did not simply dismiss me out of hand. Is it appropriate to wish you good luck with your paper, or is there a philosophical conference equivalent of the actor’s “break a leg”?

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