Abstract
If zombies were conceivable in the sense relevant to the ‘conceivability argument’ against physicalism, a certain epiphenomenalistic conception of consciousness—the ‘e-qualia story’—would also be conceivable. But (it is argued) the e-qualia story is not conceivable because it involves a contradiction. The non-physical ‘e-qualia’ supposedly involved could not perform cognitive processing, which would therefore have to be performed by physical processes; and these could not put anyone into ‘epistemic contact’ with e-qualia, contrary to the e-qualia story. Interactionism does not enable zombists to escape these conclusions.
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Notes
This outline mirrors that of Kirk (2005, pp. 39–55). However, the arguments here are significantly different (and I think clearer and more cogent) and take account of objections not considered in the book.
Stout (1931, 138f).
Some authors use “zombie” for merely behavioral duplicates, or for systems resembling us only in input-output functions; but those senses too are irrelevant here. Physicalists can consistently concede that behavioral and dispositional similarity is insufficient for mental similarity (pace Dennett, 1991, pp. 438–440): Kirk (2005, pp. 97–118). The definition of zombie twin worlds is refined in Sect. 10 below.
See for example Perry (2001). Interactionist zombists must deny that causal closure holds in our world, hence cannot define zombies as physically like us. Chalmers says the conclusion of his anti-materialist argument is not epiphenomenalism, but “the disjunction of panprotopsychism, epiphenomenalism, and interactionism” (1999, p. 493; see also Chalmers, 1996, pp. 150–160), and Sects. 10 and 11 below.
Even those epiphenomenalists who maintain that God intervenes in the world can accept it is conceivable that the physical world should have been causally closed.
Chalmers (1996, p. 359, n.2).
Chalmers uses ‘epistemic contact’ for what he calls ‘acquaintance’ with qualia (1996, p. 197). I will consider this notion later (Sect. 9, Objection 3); but I am using ‘epistemic contact’ in the broader sense indicated.
It might be suggested that causation is not necessary: mere counterfactual dependence would be enough. But the need for unconsciously persisting traces and structures would still prevent e-qualia from being capable of the necessary cognitive processing. See also Sect. 7.
E-qualists cannot deny that such a situation is possible. Since e-qualia are non-physical, neither their existence nor their non-existence can entail or be entailed by anything physical (but see n. 18).
Epiphenomenalists typically assume isomorphism. See e.g. Chalmers (1996, p. 243).
It would not help e-qualists to say e-qualia are subjectless: that would only support my claim that no one could be in epistemic contact with them. On the other hand, I see no objection to the notion of integrated, nonrelational processes of having-qualia (see Kirk, 2005, pp. 154–158)—but that is obviously inconsistent with the e-qualia story.
Thanks to a reviewer for this and the preceding objection, and for the phrasing of the suggested perspective on consciousness in an E-world.
See n. 8 above.
‘Logically’ independent in the sense that its existence was not entailed (or a priori necessitated) by the physical component.
Conscification need not be thought of as zombies becoming conscious, but only as the coming into existence of conscious subjects whose physical components had been zombies.
Cartesian zombists might demur. If thinking—a kind of activity—is essential to the soul’s existence, then ψ* cannot cease to be a cause without ceasing to exist. Also, some interactionist zombists might maintain it is a priori necessary that consciousness involves non-physical causes. See, however, the discussion of premiss (2) below. (Note that zombists cannot resist condition (i) by invoking causal essentialism, according to which a thing’s causal dispositions are essential to it. For if that doctrine is taken to entail that what physicalists count as physical items cannot conceivably exist without causing or being caused by conscious states, then zombies are inconceivable for that reason; while if it lacks that entailment, then it lets in (i).)
It would not be enough to claim that conceivably the changes might prevent ψ* from continuing to make our successors conscious; (2) says only that (ZI) entails it is conceivable that it should do so.
Here I take into account the worries mentioned in note 18.
Thanks to an anonymous reviewer for this suggestion.
Chalmers (1996, p. 197).
Zombist interactionists might consider maintaining that ψ*’s loss of causal efficacy would cut off not only epistemic contact but consciousness too. But by the argument of the last paragraph that would prevent them from being zombists.
(ZI) does not appear to entail that ψ* is caused by physical items in i, only that it is affected by them. However, given causation is contingent (n. 18), (ZI) does entail it is conceivable that ψ* should be caused physically.
Special thanks to Bill Fish for much detailed discussion and correspondence, and to David Chalmers for comments, suggestions, and encouragement through several revisions.
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Kirk, R. The inconceivability of zombies. Philos Stud 139, 73–89 (2008). https://doi.org/10.1007/s11098-007-9103-2
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DOI: https://doi.org/10.1007/s11098-007-9103-2