Seven points me to Jerry Fodor’s assessment of Strawson’s plainly named Consciousness and Its Place in Nature: Does Physicalism Entail Panpsychism?. Some very hasty thoughts on the following:
There are three philosophical principles to which Strawson’s allegiance is unshakeable. The first is that the existence of consciousness (specifically, of conscious experience) is undeniable; that we are conscious is precisely what we know best. (To be sure, we can’t prove that we are conscious; but that is hardly surprising since there is no more secure premise from which such a proof could proceed.) Strawson’s second principle is a kind of monism: everything that there is is the same sort of stuff as such familiar things as tables, chairs and the bodies of animals. This, however, leaves a lot of options open since Strawson thinks that nothing much is known about that kind of stuff ‘as it is in itself’; at best science tells us only about its relational properties. What is foreclosed by Strawson’s monism is primarily the sort of ‘substance dualism’ that is frequently (but, he thinks, wrongly) attributed to Descartes.
The third of Strawson’s leading theses is a good deal more tendentious than the first two; namely, that emergence isn’t possible. ‘For any feature Y of anything that is correctly considered to be emergent from X, there must be something about X and X alone in virtue of which Y emerges, and which is sufficient for Y.’ But Strawson holds that there isn’t anything about matter in virtue of which conscious experience could arise from it; or that if there is, we have literally no idea what it could be. In particular, we can’t imagine any way of arranging small bits of unconscious stuff that would result in the consciousness of the larger bits of stuff of which they are the constituents. It’s not like liquids (Strawson’s favourite example of bona fide emergence) where we can see, more or less, how constituent molecules that aren’t liquid might be assembled to make larger things that are. How on earth, Strawson wonders, could anything of that sort explain the emergence of consciousness from matter? If it does, that’s a miracle; and Strawson doesn’t hold with those.
The emergence problem, as well as most the suggested answers, is not a new one, and I’ve found any of its proposed solutions to be exceedingly thorny. The French materialists of the 1800s ran in circles around this issue: some went full-force into vitalism (i.e., the assignment of some mysterious “life principle” to all matter) and declared any and all matter to be capable of judgment, while others tried to negotiate compromises of assigning some sort of proto-consciousness to matter. Diderot’s solution was one of the more sophisticated, but also someone question-begging: he called all matter to be “passively” conscious, made “active” through some kind of transformation. Is this emergence or not? The problem does not appear to admit half-measures; either the raw stuff of consciousness is there, or it’s not.
This separates the problem of consciousness from the lame “half an eye” attack on evolution, which is easily answerable by saying that half-eyes existed and were evolutionarily adaptive. It’s precisely the seeming holistic nature of consciousness that makes it maddeningly intractable. But I think this is the premise that needs to be attacked, because it makes the problem seem more unsolvable than it is.
Consider the problem another way. When I’m under anesthesia, it appears (to the best of my recollection) that “my” consciousness disappears. Maybe my body or parts of it are still “conscious” in a way, but whatever constitutes consciousness in this state is wildly different from what constitutes it when I am awake, in sheer virtue of it seeming not to be “mine.” There’s always the hypothetical possibility, of course, that my memory was turned off during that time and yet I still endured all that screaming pain consciously. (The very real experience of some people who are paralyzed but not rendered unconscious and insensate by anesthesia has always struck terror in my heart.) But it seems reasonable to say that I was truly not conscious during that time.
Two points follow. The first is to say that Strawson’s definition of consciousness must apply to me while I am under the knife and anesthetized (or, for that matter, when I am dead). This destigmatizes the word “consciousness” from what we associate as human experience. The second is to ask whether consciousness is necessarily experiential. Consciousness obviously is a prerequisite for experience, but without the brain and nervous system, we have to ask what’s left of consciousness: either a destigmatized notion of “experience,” or no experience at all. In this sense, Strawson’s argument is a complement to David Chalmers’s panpsychism, which famously maintained that thermostats can be conscious because they function analogously to connectionist networks. Strawson’s argument is wholly different, but the crux of the dilemma is the same.
All I can say is that having removed the domesticated notions of “experience” and “consciousness,” the anti-emergence claim should no longer seem horribly nonintuitive. Unfortunately, though, I think the converse applies as well: there no longer seems to be an intuitive argument for the anti-emergence claim. And thus the problem transforms itself into the functionalist vs. Searlian arguments of years ago–is consciousness everywhere, or just in some sorts of matter?–but in a form I happen to consider more compelling and universal, since it no longer argues from cognitive capacities and knowledge, but from raw experience.
[There remains the problem of "mineness," which I'll try to get to at some later date.]