In this month’s issue of ‘Philosophy Now’ there are three letters giving intriguing responses my article ‘The Zombie Threat to a Science of Mind’ in last month’s issue (reprinted on this blog). Below I offer some short counter-responses.
Dave Magnall from Wilmslow Cheshire.
Dave argues that the flaw with the zombie argument is that it is set up ‘within a conceptual model that implies determinism but then neglects deterministic logic.’ My zombie twin lacks consciousness, and hence lacks free will. If it behaves just like me, this implies that I also have no free will, which Dave equates with determinism. Therefore, the thesis that zombies are possible assumes the truth of determinism. But if we are assuming determinism, then everything that happened had to happen, and hence there is no scope for talking about alternative possibilities, such as the possibility of zombies. Cool argument.
I would like to make two points in response. Firstly, Dave is assuming incompaibilism: the view that free will and determinism are incompatible. There is, however, a venerable philosophical tradition known as ‘compatibilism’ according to which human freedom is consistent with a physical world where everything that happens is determined from the big bang onwards. Secondly, determinism is the view that everything that actually happened had to happen given the laws of nature and the initial conditions of the universe. The determinist is free to entertain alternative possibilities of what might have happened if the laws of nature or the initial conditions had been different, and in this context is quite free to entertain the possibility of zombies.
Matthew Rapaport from The Internet
Matthew worries that the zombie argument begs the question (in the proper sense of this term meaning assuming what you’re trying to prove rather than the currently popular corrupt use meaning raises the question), on the grounds that asserting that zombies are possible amounts to little more than a brute denial of physicalism. Matthew says ‘The mind-brain identity view is precisely the view that zombie exact duplicates are not conceivable.’
Actually, the conceivability of zombies is not straightforwardly inconsistent with physicalism. Indeed most physicalists accept that zombies are conceivable, but deny the move from their conceivability to their possibility. Although the conclusion that zombies are possible is pretty straightforwardly inconsistent with physicalism, there are two premises leading to that conclusion (Premise 1: Zombies are coherently conceivable, Premise 2: If X is coherently conceivable, then X is possible), and each of these premises is individually consistent with physicalism. Moreover, there is a lot to be said in favour of each of these premises, which is why the zombie argument has a lot going for it!
Sheila Lockhart from Inverness
Sheila has difficulty making sense of how her zombie twin can get around the world if it completely lacks consciousness, given that ‘Using the senses without sensation would appear to be a logical impossibility.’ I think it depends what you mean by ‘senses’. The zombie receives information from the environment through it eyes, and is mechanically set up such that this information regulates its behaviour in exactly the way visual information regulates behaviour in a normal human being. In this sense the zombie ‘sees’ the environment; call this ‘thin sight’. There is another sense of ‘sight’ – call it ‘thick sight’ – according to which something doesn’t ‘see’ unless it has visual experience; obviously a zombie doesn’t ‘see’ in the thick sense. However, the zombie needn’t worry about bumping into things, as thin sight, by definition, is just as effective at getting you about as thick sight.
Perhaps Sheila thinks that this distinction between thick sight and thin sight is confused in some way, but then I think the onus is on her to explain why. Over to you.