Zombie Argument - Responses

Responses

Chalmers' argument is logically valid: if its premises are true then the conclusion must be true. However, other philosophers dispute that its premises are true. For example, is such a world really possible? Chalmers states that "it certainly seems that a coherent situation is described; I can discern no contradiction in the description." This leads to the questions of the relevant notion of "possibility": is the scenario described in premise 3 possible in the sense that is suggested in premise 2? Most physicalist responses deny that the premise of a zombie scenario is possible.

Many physicalist philosophers argued that this scenario eliminates itself by its description; the basis of physicalist argument is that the world is defined entirely by physicality, thus a world that was physically identical would necessarily contain consciousness, as consciousness would necessarily be generated from any set of physical circumstances identical to our own.

Some philosophers maintain that a possibility stronger than logical possibility is required and that, while a zombie world is logically possible, such a weak notion is not relevant in the analysis of a metaphysical thesis such as physicalism. Most agree that the relevant notion of possibility is some sort of 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" 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.

Another response is denial of the idea that qualia and related phenomenal notions of the mind are in the first place coherent concepts. Daniel Dennett and others argue that while consciousness and subjective experience exist in some sense, they are not as the zombie argument proponent claims. The experience of pain, for example, is not something that can be stripped off a person's mental life without bringing about any behavioral or physiological differences. Dennett believes that consciousness is a complex series of functions and ideas. If we all can have these experiences the idea of the p-zombie is meaningless.

Dennett argues that "when philosophers claim that zombies are conceivable, they invariably underestimate the task of conception (or imagination), and end up imagining something that violates their own definition". He coined the term zimboes (p-zombies that have second-order beliefs) to argue that the idea of a p-zombie is incoherent; "Zimboes thinkZ they are conscious, thinkZ they have qualia, thinkZ they suffer pains – they are just 'wrong' (according to this lamentable tradition), in ways that neither they nor we could ever discover!". Under (reductive) physicalism, one is inclined to believe either that anyone including oneself might be a zombie, or that no one can be a zombie – following from the assertion that one's own conviction about being, or not being a zombie is (just) a product of the physical world and is therefore no different from anyone else's. P-zombies in an observed world would be indistinguishable from the observer, even hypothetically (when the observer makes no assumptions regarding the validity of their convictions). Furthermore, when concept of self is deemed to correspond to physical reality alone (reductive physicalism), philosophical zombies are denied by definition. When a distinction is made in one's mind between a hypothetical zombie and oneself (assumed not to be a zombie), the hypothetical zombie, being a subset of the concept of oneself, must entail a deficit in observables (cognitive systems), a "seductive error" contradicting the original definition of a zombie.

Verificationism states that, for words to have meaning, their use must be open to public verification. Since it is assumed that we can talk about our qualia, the existence of zombies is impossible. A related argument is that of "zombie-utterance". If someone were to say they love the smell of some food, a zombie producing the same reaction would be perceived as a person having complex thoughts and ideas in their head indicated by the ability to vocalize it. If zombies were without awareness of their perceptions the idea of uttering words could not occur to them. Therefore, if a zombie has the ability to speak, it is not a zombie. Nigel Thomas argues that the zombie concept is self-contradictory in that, since zombies ex hypothesi behave just like regular humans, they will claim to be conscious, which, whether this claim is taken to be true, false, or neither true nor false, inevitably entails either a contradiction or a manifest absurdity.

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. Stephen Yablo's (1998) response is to provide an error theory to account for the intuition that zombies are possible. Notions of what counts as physical and as physically possible change over time so conceptual analysis is not reliable here. Yablo says he is "braced for the information that is going to make zombies inconceivable, even though I have no real idea what form the information is going to take."

The zombie argument is difficult to assess because it brings to light fundamental disagreements about the method and scope of philosophy itself and the nature and abilities of conceptual analysis. Proponents of the zombie argument may think that conceptual analysis is a central part of (if not the only part of) philosophy and that it certainly can do a great deal of philosophical work. However others, such as Dennett, Paul Churchland and W.V.O. Quine, have fundamentally different views. For this reason, discussion of the zombie argument remains vigorous in philosophy.

Another way to construe the zombie hypothesis, however, 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.