consciousness, functionalism consciousness, functionalism

Zombie Killer

Nigel J.T. Thomas Ph.D. Department of Humanities,
Rio Hondo College, Whittier, CA.

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Paper read at the Toward a Science of Consciousness (Tucson II) Conference,
Tucson, AZ, April 1996.
[Now published, in a slightly different form, in: Stewart R. Hameroff, Alfred W. Kaszniak, & Alwyn C. Scott (eds.). Toward a Science of Consciousness II: The Second Tucson Discussions and Debates. Cambridge, MA: MIT Press, 1998, pp. 171-177. So far is possible, any citations should be made to this published version]


     Philosopher's zombies are hypothetical beings behaviorally, functionally, and perhaps even physically indistinguishable from normal humans, but who lack our consciousness. Many people seem to be convinced that such zombies are a real conceptual possibility, and that this bare possibility entails that understanding human consciousness must remain forever beyond the reach of science. However, the conceptual entailments of zombiehood have not been sufficiently examined. This brief article shows that any way of understanding the behavior of zombies that does in fact support the suggested entailment, leads to contradictions and absurdities. Zombies are not conceptually possible.

Note 1: Although this paper may read like a defense of conventional computational functionalism, that is not really my aim. I dislike the zombie argument because, by erecting a spurious problem with functionalism, it actively misdirects our attention away from the real deficiencies of the doctrine. It is surely no accident that most functionalists find the idea of the zombie so compelling. The doctrine that cognitive mental states (and even some emotional ones) are to be identified with functionally defined brain states seems to explain quite a lot, and is quite appealing so long as one ignores the fact of consciousness (as people usually did in the era when the functionalist doctrine was first being developed). Once we remember that fact, however, functionalism can only be saved either by making the arbitrary stipulation that, as a matter of brute inexplicable (and non-explanatory) metaphysical fact, functional states of mind-brains just are conscious states, or else (more plausibly) by restricting the scope of functionalism just to the non-conscious aspects of mentality, and thus admitting the possibility of functional zombies. The fact that zombies are not possible is thus a sign of an incoherence in functionalism even if (following the zombiphiles) we construe it as merely a theory of cognition rather than a complete theory of mind. This suggests that it is impossible properly to understand consciousness and cognition independently of one another.

Note 2: Although it can be considered a defence of physicalism, Zombie Killer gives only the barest hint of what I think a physicalist theory of consciousness actually ought to look like. For my positive views about consciousness, see the following (all available on this site):

Note 3: Although the Zombie Killer paper is now in print, I would prefer that the version presented here be considered the definitive one. It is what I actually wrote. The published version was severely hacked about by an overzealous and philosophically incompetent copy editor. Several logical and terminological errors were introduced, as well as many stylistic changes, very few of which seemed to me to be improvements. Although I did manage to get the worst errors corrected at the proof stage, many of the gratuitous stylistic changes remain, and, as I never got a chance to see the final printer's proofs due to this debacle, there are also some typographical errors in the published version. (I understand that I was not the only contributor to the book to have a problem with the copy editing!) Despite this, please make any citations to the published version whenever possible

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Web pages devoted to philosophical zombies

Zombies on the Web

by Dave Chalmers

Zombies (from the Stanford Encyclopedia of Philosophy)
by Robert Kirk

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