Galen Strawson in Little Gray Cells:
The intuitive puzzle is clear, and McGinn presents it with multilayered intensity. He is right that we can never hope to understand how consciousness as we know it in everyday life relates to the brain considered as a lump of matter. But it doesn't follow that consciousness is a mystery -- except insofar as everything is. This move rests on a large assumption that is almost universally held, although it is certainly false.
This is the assumption that we have a pretty good understanding of the nature of matter -- of matter in space -- of the physical in general. It is only relative to this assumption that the existence of consciousness in a material world seems mystifying. For what exactly is puzzling about consciousness, once we put the assumption aside? We know just what it is like. Suppose you have an experience of redness, or pain, and consider it just as such. There doesn't seem to be any room for anything that could be called failure to understand what it is. You know what it is.
BV comments: Strawson is right about one thing: we know what consciousness is from our own case. We experience pains and pleasures, and so on. (And he is also right to avoid the eliminativism that tempts many.) But he misses the problem that McGinn so masterfully presents. It is is not consciousness as we experience it that is puzzling, but how consciousness arises from the gray matter in our skulls. We understand consciousness from the first-person point of view, and our physics gives us a very good understanding of matter from the third-person point of view. What we don't understand is how matter can be conscious.
It is not consciousness that is puzzling, then, but matter. What the existence of consciousness shows is that we have a profoundly inadequate grasp on the nature of matter. McGinn agrees with this last point, in fact: with considerable speculative panache, he develops the idea that there must be something deficient in our idea of space, as well as in our idea of matter. But he still wants to stress the mysteriousness of consciousness; to which the reply, once again, is that we find consciousness mysterious only because we have a bad picture of matter.
BV: Strawson is not making sense. There is nothing particularly puzzling about consciousness, and, contrary to what he says, there is nothing particularly puzzling about brains. What is puzzling is how a brain can be conscious. He doesn't seem to grasp the problem. Besides, how can the existence of consciousness show that we have an inadequate grasp of matter? What does that even mean?
Can anything be done? I think physics can help, by undermining features of our picture of matter that make it appear so totally different from consciousness. The first step is very simple: to begin with, perhaps, one takes it that matter is simply solid stuff, uniform, non-particulate (the ultimate Norwegian cheese). Then one learns that it is composed of distinct atoms -- solid particles that cohere closely together to make up objects, but that have empty space (roughly speaking) between them. Then one learns that these atoms are themselves made up of tiny, separate particles, and full of empty space themselves. One learns that matter is not at all what one thought.
Now one may accept this while retaining the idea that matter is at root solid, dense lumpen stuff, utterly different from consciousness. For so far this picture preserves the idea that there are true particles of matter: tiny grainy bits of ultimate stuff that are in themselves truly solid. And one may say that only these, strictly speaking, are matter -- matter as such. But it's been a long time since the 18th-century philosopher-chemist Joseph Priestley pointed out that there are no scientific grounds for supposing that the fundamental constituents of matter have any truly solid central part, and the picture of grainy, inert particles has effectively disappeared in the strangenesses of modern quantum theory and superstring theory.
Current physics, then, thinks of matter as a thing of forces, energy, fields. And it can also seem natural to think of consciousness as a form or manifestation of energy, as a kind of force, and even, perhaps, as a kind of field. You may still feel the two things are deeply heterogeneous, but you really have no good reason to believe this. You just don't know enough about matter. When McGinn speaks of the ''squishy'' brain, he vividly expresses part of our ordinary idea of matter. But when physics inspects the volume of space-time occupied by a brain, what does it find? It finds a vibrant play of energy, an astonishingly insubstantial, radiant form.
All this being so, do we have any good reason to think that we know anything about the physical that legitimates surprise at the thought that consciousness is itself wholly physical? We do not. And that is the first, crucial step that one must take when facing up to the problem of consciousness.
BV: Strawson is maintaining that the sense of the utter heterogeneity of matter and consciousness arises from an inadequate conception of matter, and that if we had an adequate conception the sense of heterogeneity would dissipate. We would then understand consciousness to be a purely material phenomenon. Now it is true that our concept of matter is pegged to the state of physics, and also true that we now have a more adequate conception of matter than we had in earlier centuries. Well, suppose the volume of space-time occupied by a brain is filled with "a vibrant play of energy, an astonishingly insubstantial, radiant form," as Strawson lyrically puts it. The problem remains: how does brain matter so conceived give rise to consciousness, not to mention thought? The problem remains on any extant conception of matter, no matter how "insubstantial." Strawson is fooling himself if he thinks that the problem arises only on the assumption that matter is the 'ultimate Norwegian cheese."
Strawson is doing nothing more than giving expression to his faith and hope that someday physics will have advanced to the point where it will become intelligible how the brain matter in animals of our complexity can be conscious. But he has no idea of what the solution will look like. He is gesturing hopefully in the direction of he-knows-not-what. Both he and McGinn are naturalists. But he is an optimist where McGinn is a pessimist. Strawson pins his hopes on future physics. McGinn has no such faith or hope. His view is that the matter-consciousness problem has a solution but it is one our cognitive architecture prevents us from ever knowing.
Both philosophers are naturalists who maintain that there is nothing non-natural or supernatural about consciousness. I am not a naturalist. But if I were I would say that McGinn's position is the more reasonable of the two. What best explains the intractability, hitherto, of the problems in the philosophy of mind? Our lack of understanding of physics, or something about our cogntive architecture that makes it impossible for us to grasp the solution? I'd put my money on the latter.
So far, then: McGinn 1; Strawson 0.