The claim, briefly is that any successful theory of consciousness – in fact, any metaphysical theory – will have to include some core elements that are clearly crazy. “Crazy” is taken to describe any thesis which conflicts with common sense, and which we have no strong epistemic reason for accepting.
Schwitzgebel defends this thesis mainly by surveying the range of options available in philosophy of mind and pointing out that all of them – even those which set out to be pragmatic or commonsensical – imply propositions which are demonstrably crazy. I think he’s right about this; I’ve observed myself in the past that for any given theory of consciousness the strongest arguments are always the ones against: unnervingly this somehow remains true even when one theory is essentially just the negation of another theory. Schwitzgebel suggests we should never think that our own preferred view is, on balance, more likely than the combination of the alternatives – we should always give less than 50% credence to our preferred view or, if you like, never quite believe anything.
I won’t recapitulate Schwitzgebel’s case here, but it did provoke me to wonder about the issue of what we would find acceptable as an answer to the problem of consciousness. It’s certainly true that some theories would not, as it were, be crazy enough to appeal. Suppose the Blue Brain project triumphed, and delivered a brain simulated down to neuronal level. We could run the simulation and predict the brain’s behaviour; for anything the simulated person said or thought, we could give a complete neuronal specification, and in that sense a complete explanation. But it wouldn’t seem that that really answered any of the deeper questions.
Equally, for all those theories that tell us there’s really nothing to explain, our consciousness and our selfhood are just delusions generated by aspects of the mental mechanism, one problem is that the answer seems too easy (though in another sense these views are surely crazy enough). We don’t want to be told to move along, nothing to see here, folks; what we want is an “Aha!” moment, a theory that makes things suddenly fall into places where they make dramatic new sense. How do we get such moments?
I think they come from a translation or bridge that lets us see how one understood realm transfers across into another realm which is also understood but not connected. Maybe we find out that Hesperus is Phosphorus and that both are in fact the planet Venus; then the strange behaviour of the evening star and the morning star suddenly make more sense. Another related way of generating the Aha! is to discover that we have been conceptualising things wrongly: that two things we thought were separate are really aspects of the same thing, or that a thing we took to be a single phenomenon is actually two different things we have conflated together: temperature and heat, for example.
It certainly looks as if consciousness is right for an Aha! of those kinds – we have the two separate realms, the mental and the physical, all ready to go. But Colin McGinn has argues that the very distinctness of the realms means that no explanation can ever be forthcoming, and many people since Brentano have shared the sense that no bridging or reshuffling of concepts is even conceivable. The thing is, we don’t get the kind of paradigm shift we need by labouring away within the existing framework: we need something to jolt us out of it and there’s no telling what. We know now that in order to come up with the theory that speciation occurs through differential survival of the fittest, you needed to visit the tropics and collect a lot of examples of local fauna, read Malthus and then fall ill. Darwin and Wallace both had their dogmatic slumbers shaken up in this way; but it was not evident in advance that that was what it took. Perhaps even now a young doctor who has treated schizophrenics, has had the required motorbike accident and is just about to read the text on encryption which is an essential precursors to the Theory.
I sort of hope and believe that something like that is the case and that when the Theory is available we shall see that one of those theses that look crazy now are not quite what we thought: so crazyism will turn out to be false, or at any rate only provisional. But Schwitzgebel’s essential pessimism could turn out to be justified. We could end up with a theory like quantum mechanics, which seems to do the job so far as anyone can see, but which just refuses to click with our brains positively enough for the Aha! moment.
Schwitzgebel doesn’t spend much time on the wider claim that metaphysics as a whole is crazy, but it’s an interesting possibility that the problem doesn’t really lie with philosophy of mind but something altogether deeper. Maybe we need to look away from the mind as such and spend some time on… what? Causality? Basic ontology? Once again, I have no idea.