Some critics will no doubt respond that it is still imaginable that you and I are functionally identical in all relevant respects yet phenomenally different. But this claim presents a problem at least for those who oppose functionalism but who accept physicalism. We ought to accept both, for it is just as easy to imagine that there are inverted qualia in molecule-by-molecule duplicates (in the same external, physical settings) as it is to imagine inverted qualia in functional duplicates. If the former duplicates are really metaphysically impossible, as the physicalist is committed to claiming, why not the latter? Some further convincing argument from Block needs to be given that the two cases are disanalogous.
(Of course, this response does not apply to those who take the view that qualia are irreducible, non-physical entities. However, according to Davidson these authors have other severe problems of their own, like phenomenal causation. Given the causal closure of the physical, how can objections having to do with qualia make any difference? Hence: closet dualism.)
What about the so-called “absent qualia hypothesis”? On this view functional duplicates of conscious creatures are possible, duplicates that entirely lack qualia. (That is, the problem of “zombies”.) While in some sense this example is insensitive to argument, it is sensitive to intuitions, and by showing that our intuitions might fail, I believe there is something salvageable in this argument.
Ned Block asks us to suppose that a billion Chinese people are each given a two-way radio with which to communicate with one another and with a brainless body. The movements of the body are controlled by the radio signals, and the signals themselves are made in accordance with instructions the Chinese people receive from a vast display in the sky which is visible to all of them. The instructions are such that the participating Chinese people function like individual neurons, and the radio links like synapses, so that together the Chinese people duplicate the causal organization of a human brain. Whether or not this system, if it were ever actualized, would actually undergo any feelings and experiences, it seems that the commonsense crowd says that it does not. The argument is that if this is a real metaphysical possibility, then qualia do not have functional essences.
The conclusion that Block and Shoemaker would have us come to is that the China-body is a gigantic zombie, and we are supposed to believe this is an absurd conclusion. While the proposition, “The Republic of China is a zombie,” might make sense metaphorically and politically, it makes little sense metaphysically.
If we disagree with Chalmers and Dennett about qualia, and are compelled to give in to zombie arguments, then the best functionalist reply to Block’s China-body system is to bite the bullet and to argue that however strange it seems, the China-body system could not fail to undergo qualia. This sort of hypothesis might seem attractive to authors with wild dualist ideas about some sort of Hegelian World Spirit, but when it is seen to apply to every functional system, then it appears very monistic—or very much like anomalous monism. The more the consciousness is separated from our individualistic notion of a first-person point of view, the less plausible it seems to talk about inner-states in the functionalist paradigm. My strategy with this example is to push the functionalist argument far enough so that it accepts inner-states for all systems.