Philosophical zombie

From Wikipedia, the free encyclopedia
  (Redirected from Philosophical Zombie)
Jump to: navigation, search
For other uses, see Zombie (disambiguation).

A philosophical zombie or p-zombie in the philosophy of mind and perception is a hypothetical being that is indistinguishable from a normal human being except in that it lacks conscious experience, qualia, or sentience.[1] For example, a philosophical zombie could be poked with a sharp object, and not feel any pain sensation, but yet, behave exactly as if it does feel pain (it may say "ouch" and recoil from the stimulus, or say that it is in intense pain).


Types of zombie[edit]



  • A behavioral zombie that is behaviorally indistinguishable from a human.
  • A soulless zombie that lacks a soul.

Zombie arguments[edit]



  2. Thus, if physicalism is true, a metaphysically possible world in which all physical facts are the same as those of the actual world must contain everything that exists in our actual world. In particular, conscious experience must exist in such a possible world.

The above is a strong formulation of the zombie argument. There are other formulations of the zombies-type argument which follow the same general form. The premises of the general zombies argument are implied by the premises of all the specific zombie arguments. A general zombies argument is in part motivated by potential disagreements between various anti-physicalist views. For example an anti-physicalist view can consistently assert that p-zombies are metaphysically impossible but that inverted qualia (such as inverted spectra) or absent qualia (partial zombiehood) are metaphysically possible. Premises regarding inverted qualia or partial zombiehood can substitute premises regarding p-zombies to produce variations of the zombie argument. The metaphysical possibility of a physically indistinguishable world with either inverted qualia or partial zombiehood would imply that physical truths don't metaphysically necessitate phenomenal truths. To formulate the general form of the zombies argument, take the sentence 'P' to be true if and only if the conjunct of all microphysical truths of our world obtain, take the sentence 'Q' to be true if some phenomenal truth, that obtains in the actual world, obtains. The general argument goes as follows.

  1. It is conceivable that P is true and Q is not true.
  2. If it is conceivable that P is true and Q is not true then it is metaphysically possible that P is true and Q not true.
  3. If it is metaphysically possible that P is true and Q is not true then physicalism is false.
  4. Therefore, physicalism is false.[9]

Q can be false in a possible world if any of the following obtains: (1) there exists at least one invert relative to the actual world (2) there is at least one absent qualia relative to the actual world (3) all actually conscious beings are p-zombies (all actual qualia are absent qualia).




One can hold that zombies are a logical possibility but not a metaphysical possibility. If logical possibility does not entail metaphysical possibility across the domain of relevant truths, then the mere logical possibility of zombies is not sufficient to establish their metaphysical possibility. The zombie argument claims that one can tell by the power of reason that such a "zombie scenario" is metaphysically possible. Chalmers states; "From the conceivability of zombies, proponents of the argument infer their metaphysical possibility"[8] and argues that this inference, while not generally legitimate, is legitimate for phenomenal concepts such as consciousness since we must adhere to "Kripke's insight that for phenomenal concepts, there is no gap between reference-fixers and reference (or between primary and secondary intentions)." That is, for phenomenal concepts, conceivability implies possibility. According to Chalmers, whatever is logically possible is also, in the sense relevant here, metaphysically possible.[11]




Artificial intelligence researcher Marvin Minsky sees the argument as circular. The proposition of the possibility of something physically identical to a human but without subjective experience assumes that the physical characteristics of humans are not what produces those experiences, which is exactly what the argument was claiming to prove.[14] Richard Brown agrees that the zombie argument is circular. To show this, he proposes "zoombies", which are creatures nonphysically identical to people in every way and lack phenomenal consciousness. If zoombies existed, they would refute dualism because they would show that consciousness is not nonphysical, i.e., is physical. Paralleling the argument from Chalmers: It's conceivable that zoombies exist, so it's possible they exist, so dualism is false. Given the symmetry between the zombie and zoombie arguments, we can't arbitrate the physicalism/dualism question a priori.[15]



Some accept modal reasoning in general but deny it in the zombie case. Christopher S. Hill and Brian P. Mclaughlin suggest that the zombie thought experiment combines imagination of a "sympathetic" nature (putting oneself in a phenomenal state) and a "perceptual" nature (imagining becoming aware of something in the outside world). Each type of imagination may work on its own, but they're not guaranteed to work when both used at the same time. Hence Chalmers's argument needn't go through.[17]:448 Moreover, while Chalmers defuses criticisms of the view that conceivability can tell us about possibility, he provides no positive defense of the principle. As an analogy, the generalized continuum hypothesis has no known counterexamples, but this doesn't mean we must accept it. And indeed, the fact that Chalmers concludes we have epiphenomenal mental states that don't cause our physical behavior seems one reason to reject his principle.[17]:449–51

Another way to construe the zombie hypothesis is epistemically – as a problem of causal explanation, rather than as a problem of logical or metaphysical possibility. The "explanatory gap" – also called the "hard problem of consciousness" – is the claim that (to date) no one has provided a convincing causal explanation of how and why we are conscious. It is a manifestation of the very same gap that (to date) no one has provided a convincing causal explanation of how and why we are not zombies.[18]

Related thought-experiments[edit]




See also[edit]



  1. ^ a b Kirk, Robert. "Zombies". The Stanford Encyclopedia of Philosophy (Summer 2009 Edition), Edward N. Zalta (ed.). 
  3. ^ a b Dennett, Daniel C. (1991). Consciousness Explained. Boston, Toronto, London: Little, Brown and Co. ISBN 0-316-18065-3. 
  4. ^ a b c d Dennett, Daniel C. (1995). Darwin's Dangerous Idea. New York: Simon & Schuster. p. 322. ISBN 0-684-82471-X. 
  5. ^ Harnad, Stevan (2000). "Minds, Machines, and Turing: The Indistinguishability of Indistinguishables". 9(4): 425–445. Journal of Logic, Language, and Information. 
  6. ^ Robinson, Howard. "Dualism". The Stanford Encyclopedia of Philosophy (Fall 2009 Edition), Edward N. Zalta (ed.). 
  7. ^ Kripke, Saul. Naming and Necessity (1972)
  8. ^ a b Chalmers, 2003, p. 5.
  9. ^ Chalmers, 2010, p. 106-109
  10. ^ Chalmers, 1996, p. 96.
  11. ^ Chalmers, 1996, pp. 67–68.
  12. ^ Dennett 1995; 1999
  13. ^ Thomas, 1998, see
  14. ^
  15. ^ Brown, Richard (2010). "Deprioritizing the A Priori Arguments Against Physicalism" (PDF). Journal of Consciousness Studies 17 (3-4): 47–69. 
  16. ^ Yablo, 2000, §XV.
  17. ^ a b Christopher S. Hill; Brian P. Mclaughlin (Jun 1999). "There are Fewer Things in Reality Than are Dreamt of in Chalmers's Philosophy". Philosophy and Phenomenological Research 59 (2): 445–454. doi:10.2307/2653682. 
  18. ^ Harnad, Stevan (1995) "Why and How We Are Not Zombies. Journal of Consciousness Studies 1:164–167


  • Chalmers, David. 2010. "the character of consciousness", OUP

External links[edit]