Whatever, you may be wondering, became of the mind-body problem? This new collection of Colin McGinn’s philosophical papers is as good a place to find out as any I know of. Published over a period of more than a decade, and drawn together from the usual motley of largely inaccessible academic journals, these essays provide a vivid introduction to current views in the philosophy of mind and to their immediate precursors. Professionals will find, in the earlier publications (which, confusingly, come last in the book), a fascinating record of what happened to the philosophy of mind in England when Davidson and Kripke hit town. Professionals and laity alike will find, in the later publications, an up-to-date, sophisticated and enjoyably tendentious account of the present state of the art.
Mental phenomena present three embarrassing questions to any world view that purports to be even vaguely materialist: ‘How could anything material be conscious (in the way that, for example, pains and after-images are)?’ ‘How could anything material be rational (in the way that, for example, thoughts and inferences are)?’ ‘How could anything material be about anything (in the way that, for example, ideas and beliefs are)?’ Taken together, the second and third questions constitute what is called the problem of intentionality: ideas and beliefs purport to represent an extra-mental reality, in respect of which they are evaluable as true or false. The rationality of mental processes (thinking, inferring and the like) arguably consists of their being truth-preserving; in a properly conducted mental life ‘one true inference invariably suggests others,’ as Sherlock Holmes somewhere remarks. If you are a materialist, you will wonder how any of this can be true of mere stuff and matter – of mere brains, as it might be. And even if you are not a materialist, you might reasonably wonder how it can be true of anything at all. It is, after all, no clearer how souls could think or feel than how brains could.
It used to be universally taken for granted that the problem about consciousness and the problem about intentionality are intrinsically linked: that thought is ipso facto conscious, and that consciousness is ipso facto consciousness of some or other intentional object. In consequence, although the mind-body problem was generally conceded to be quite hard enough, thank you, at least there was supposed only to be one of it. Solve the consciousness-brain problem and you’ll get the intentionality-brain problem for free: or vice versa. So it was assumed.
Freud changed all that. He made it seem plausible that explaining behaviour might require the postulation of intentional but unconscious states. Over the last century, and most especially in Chomskian linguistics and in cognitive psychology, Freud’s idea appears to have been amply vindicated. ‘Unconscious mental process’ has come to sound decreasingly oxymoronic. The experimental investigation of unintrospectible thoughts is now the bread and butter of cognitive scientists, among whom the prevailing view is that mental processes are rational because they are computational.
If this is right, then to understand how a mechanism could be computational is to understand how it could be rational. And we do understand how a mechanism could be computational; if we didn’t, we couldn’t build computers.
This is breathtaking if correct; it is, perhaps, the first real insight anyone has had into how minds could be part of the natural order. The implications for philosophy are only just coming to be digested. One problem – the one McGinn’s book highlights – is that the more we understand about how brain processes could be rational, the less we see how their rationality is connected to their consciousness. As McGinn rightly says, ‘a proper theory of consciousness in terms of properties of the brain should make it intelligible that the brain is the basis of consciousness, but the computational properties of the brain do not furnish such a theory: it remains a mystery how cerebral computations could give rise to consciousness, as much a mystery as how mere matter could form itself into the organ of consciousness.’
The result is a situation that many philosophers find simply scandalous: the people who know most about how brains manage to be smart care least about how brains manage to be sentient. Cognitive scientists mostly think that consciousness is a damned nuisance: a pathological condition that some neural/computational circuits are prone to. Or they don’t think about consciousness at all. Dividing and conquering – concentrating on intentionality and ignoring consciousness – has proved a remarkably successful research strategy so far. But, it is, of course, doomed in the long run if the link between the two should turn out, after all, to be intrinsic. John Searle has recently been dining out on this line of thought.
That, then, is the background for the most interesting of McGinn’s papers, which are, fortunately, also the ones that philosophy buffs will find most accessible. As I read him, McGinn has four main claims on offer. First, the problem of consciousness isn’t a philosophical illusion. It isn’t going to be cured by Wittgensteinian therapy, or bypassed by eliminative materialism, or reduced away by conceptual analysis; it won’t in short, succumb to any of the tricks that philosophers use when they want to make their problems ‘dissolve’. Second, though the problem of consciousness is reals and pressing, it’s not going to be solved, because it’s just too hard. Either we’re not smart enough for the mind-body problem, or – what maybe comes to the same thing – we’re smart in the wrong way. Consciousness is (in Chomskian terminology that McGinn appropriates) not a problem but a mystery; and the mystery is intractable. Third, cognitive science notwithstanding, the mind-body problem for consciousness infects the mind-body problem for intentionality, so if we’re not going to get a solution for the one, we also aren’t going to get a solution for the other – not, at least, a ‘full’ or ‘complete’ solution. And fourth, although we aren’t going to figure out how mere matter can be conscious, this ought not shake us in our materialism:
the more you think about consciousness the more puzzling it comes to seem. It is comforting to reflect that from God’s point of view, i.e. the point of view of Nature, there is no inherent mystery about consciousness at all. The impression of mystery derives from our own incurable cognitive poverty, not from the objective world in which consciousness exists. There is no real magic in the link between mind and matter, however incapable we are of seeing how the trick is performed.
I am, I guess, variously moved by these four theses. It seems to me that McGinn is very likely right about the first. Heaven knows, we’re confused enough about consciousness: but I don’t think it’s the ‘I wonder what time it is on the Sun when it’s three o’clock in Omaha’ kind of confusion – the kind of confusion that goes away when you get your concepts under control. There is, to quote a resonant phrase of Tom Nagel’s that McGinn approves of, ‘something it’s like’ to be in a conscious state, and we do not understand how there could be anything that it’s like to be in a material condition. The perplexity about how anything material could be conscious is even worse than the perplexity about how anything material could be alive (an analogy to which McGinn instructively draws our attention). To be alive is to have certain capacities. There are all sorts of things that living people can do but dead people can’t: eat, drink, sing, heal their wounds, propagate their kind, and so on. A materialist theory of life would be an explanation of how something material could do those sorts of things. We can therefore give an account of what a theory life has to explain without having to invoke the concept of a living thing. We can say, in non-question-begging terms, what a theory of life is a theory about.
But the situation seems not to be like this in the case of the theory of consciousness; it’s not clear that there are capacities that depend on consciousness as such. That is, it’s not clear that there are capacities you have only if you are in a state that there is something that it’s like to be in. Consciousness, it would seem, is just the capacity to be in states that are, well, conscious. The problem of consciousness seems therefore to be completely isolated from the rest of what psychologists work on. That’s the gloomy side of the cheerful news that the cognitive science strategy of bypassing the problem apparently works. There seems to be no way out of the problem of consciousness because there seems to be no way into it.
Is the solution of the mind-body problem beyond us; is it just too hard for our kind of mind? Pessimism draws the inductive conclusion from a history of unremitting failure. Optimism remarks that problems that seem utterly intractable have been known to turn inside out when somebody has a good idea. The issue seems academic even by academic standards; what’s clear is that nobody has had any good ideas about consciousness yet.
The third claim, that the connection between consciousness and intentionality is intrinsic (the ‘attempted extrusion of the subjective from the semantic just does not work’), is the one that will worry cognitive scientists most; I admit to its worrying me. This issue, though pregnant, is technical and I can’t do more than give the flavour of it here.
McGinn’s basic idea is that, for at least some conscious states – viz. perceptual sensations – the connection between intentional properties and conscious (‘qualitative’) properties is ‘anything but contingent’, so a ‘full’ or ‘complete’ explanation of the former must willy nilly invoke the latter. (McGinn rests a lot, in my view too much, on the claim that a theory of intentionality without a theory of consciousness couldn’t be ‘complete’. What, exactly, is a complete explanation, one wonders? And are there any examples of the kind?) ‘The content of an experience simply does contribute to what it is like to have it, and indeed it is not at all clear that anything else does. A visual experience, for example, presents the world to the subject in specific ways, as containing spatially-disposed objects of various shapes and colours, and this kind of “presentation-to” is constitutive of what it is like to have visual experience.’
I’m not convinced that this is right; I certainly hope that it isn’t. For one thing, somebody who is as thoroughgoing a Realist about qualitative properties as McGinn surely ought to take inverted spectra to be conceptually possible. (This is the conceptual possibility that what looks to you the way that red things do to me might look to me the way green things do to you.) But if spectrum inversion is conceptually possible, then it presumably follows that the connection between qualitative content and intentional content isn’t internal. Not, at least, if ‘intentional content’ means something like ‘truth conditions’. For if, in the case imagined, we both look at the same tomato, we have qualitatively different visual experiences that are nevertheless caused by, and true of, the very same thing. Or again: it appears that after-images, memory images and the like can exhibit figural ambiguities. Retinally-stabilised after-images of the Necker cube reverse, just like the drawings in a Psychology text. This suggests that their qualitative character doesn’t, after all, determine the satisfaction conditions of mental images – no more than a line drawing of a Necker cube determines its spatial orientations.
These matters are, however, far from settled. McGinn may be right about the limitations of divide and conquer. But it is surely remarkable – it is itself a fact in need of explanation – that divide and conquer has worked so well so far. Descartes wouldn’t have given tuppence for its chances.
Finally, suppose that the problems about consciousness really are intractable: how much is our materialism prejudiced? McGinn tells us again and again that consciousness can’t really be miraculous; that, even though we don’t know how consciousness could ‘arise’ from a material substrate, we do know that it does; that the problem of consciousness probably isn’t intrinsically hard (it’s only hard for us). And so on. He also tells us, however, that all of this is perhaps cold comfort, and I do think that is so.
The notion of a miracle is self-cancelling. If miracles did happen, they would be part of the natural order too, there being no place else for them to happen in. Conversely, to say something isn’t miraculous – that it isn’t intrinsically inexplicable – is, I suppose, just to say that it happens. The only substantive notion of explanation we have is, after all, extrinsic: it’s the notion of explanation for us. What, then, is the difference between there being no explanation of consciousness and there being one that only God can understand? I’m not consoled by the news that consciousness looks okay to God; miracles would too.
In this respect, it seems to me, McGinn is, uncharacteristically, inadequately depressed. If, as McGinn supposes, the problem about consciousness really isn’t just a muddle, then there is something going on that we deeply do not understand, something that our best science gives no hint of accommodating. Perhaps there is some sense in which that might be true and materialism still be vindicated: but it looks to me like what’s left of materialism if consciousness eludes it as a matter of principle is hardly going to be worth defending. Materialism is supposed to be an ontological thesis, but mostly it’s epistemology in disguise. What we imagine to be compatible with our materialism is, I think, just about the same as what we can imagine ourselves being able to explain. That consciousness might be the one but not the other strikes me as a wan doctrine and an empty hope.
The trick in the philosophy of consciousness would be to find a middle way between Chicken Little and the ostrich. I don’t think McGinn has managed this; I don’t think that anybody has. But, unlike many philosophers who discuss the issue, McGinn has the good sense to err largely on the Chicken Little side. The wise bird always assumes that the sky is falling unless it is quite certain that it’s not. If you want to read somebody clever worrying about a problem that’s worth somebody clever’s worrying about, read The Problem of Consciousness.