Putnam, Searle and Bishop: The Failure of Physicalist Computationalism

I wanted to come out of blog dormancy to write up my thoughts on what I feel is a very important argument against computationalism. The argument advances the view that there is no objective fact of the matter about which computations a physical system is computing, and if this is the case it would certainly seem to problematise computationalism (the view that what it is to be a conscious mind is just to perform the right kind of computation).

In this post I will explain the argument and some of the common responses to it. I'll reserve my own response (which is quite different from that of most computationalists) for a future post.

In Defence of Strong AI: Philosophical Zombies Refuted

One concept that often comes up in discussions about consciousness and strong AI is that of the philosophical zombie.

Generally, a philosophical zombie is something which looks like and behaves like a human being, but has no conscious experience of the world. It may deceive us by protesting that it is conscious and claiming that it does feel pain and experience sensations just as we do, but it is just an automaton mimicking a real sentient being. It is no more aware than a character in a novel or a two-line computer program that prints to the screen the message "Hello World! (I'm conscious, by the way)".

Opponents of strong AI will often bring up the idea of a philosophical zombie to illustrate that it is conceivable that something can behave as though it were conscious while actually having no inner experiences whatsoever. David Chalmers, in The Conscious Mind, discusses the idea of an entire world, perhaps indistinguishable from our own, which is populated entirely by philosophical zombies.

While those who bring up the concept may not claim that philosophical zombies are possible in this universe, they do maintain that the concept is at least logically possible or coherent. I disagree.