These metaphysical questions are difficult, and simple solutions obviously don’t work or the debates would have ended long ago. What this means to me is that the common presumption that something like physicalist monism should be the "default" metaphysical position is unfounded. More "extravagant" metaphysical systems need to be weighed in the quest to find a better mousetrap for explaining how the world works.
I think that's well expressed -- but I also find it a sign of a disturbing tendency (or at least a possible tendency) to simply or effectively abandon the goal of understanding consciousness in a scientific sense. We can see something like that tendency again in a recent blog post by David Chalmers that interpreted Jaegwon Kim as backing away from physicalism, and adding: "... this makes at least three prominent materialists who have abandoned the view in the last few years". And, with a certain irony, I think we can also see this in the repeated hopes that maybe a "new physics" or some quantum oddity will be needed to cope with consciousness (see Conscious Entities, Nov 10/05) -- these hopes may appear to rely on science, but really, in their invocation of mysterious, unknown theories, become a way of effectively obscuring the problem.
This, of course, is making the assumption that resort to non-physicalist accounts of consciousness (or, generally, anything) represent a form of abandonment of science. I think that's the case, since I think that terms like "physicalist" or "naturalistic" really take their meaning from science -- that is, they can include anything that science itself includes. But it may be that some of this apparent tendency is not so much a reaction against science itself but really against over-reaching by some proponents of a scientific approach, particularly against the sometimes blustery defensiveness that such proponents can display when their grand claims are questioned. This isn't to question real or actual projects in neuroscience or cognitive science as such, in other words, but rather some philosophical stances that are influenced by the goals of such sciences, but are driven to make claims or denials that appear more ideological than scientific. And one of the more egregious illustrations of that is the claim, by Dennett, for example, and some of his more excitable "computationalist" followers, that "qualia" as such don't exist*. Now, qualia, as we've seen, have famously been called "the hard problem of consciousness" (Chalmers), and rightly so, I think, because, for all of Dennett's long-winded hard work manning his various "intuition pumps", the simple fact of phenomenal experience (call it what you will) leaves it still fundamentally ineffable, private, and immediate**. But Dennett's reason for trying so hard to deny this is made evident by just inverting the motivations he attributes to the defenders of qualia:
I suspect, in fact, that many are unwilling to take my radical challenge seriously largely because they want so much for qualia to be acknowledged. Qualia seem to many people to be the last ditch defense of the inwardness and elusiveness of our minds, a bulwark against creeping mechanism. They are sure there must be some sound path from the homely cases to the redoubtable category of the philosophers, since otherwise their last bastion of specialness will be stormed by science.
No doubt this is true for many, as we've seen from the revivals of dualism, panpsychism, platonism, and quantum mysticism. But the reverse wishes also exist: people who want so badly for "mechanism" to triumph that they're anxious to banish, deny, ignore, or "explain away" any phenomena that seem conceptually difficult for a mechanistic orientation -- even phenomena that are quite literally right before their eyes. But "ineffable, private, and immediate" experience, while problematic, doesn't equate to mystic, and certainly doesn't imply "non-physical" -- in an obvious sense, in fact, what we see, hear, touch, etc., is the very essence and basis of the physical. These "computationalists" concede too quickly and too much to the anti-physicalists in accepting their inferences, in other words, and their rigid defenses make their position more a matter of doctrine than of either science or philosophy -- in both ways, they hurt more than help the physicalist program.
*He either denies qualia exist, or, for him equivalently, claims that, for example, a sufficiently sensitive or discriminating machine for analyzing the chemical composition of wine (and, I guess, emitting the results using canned wine-snob phrases) would actually experience the taste of the wine.
** I've left out "intrinsic" from Dennett's list of deniable attributes since I'm unclear what he means by it.
I won't try to make a counter-argument for the other three attributes here -- I would say that I think Dennett mounts a good critique of a number of assumptions that have often gone along with qualia, and a more modest aim might have led to a better result. As it is, he's left with a reluctant late admission that there may indeed be "primary or atomic properties of what one consciously experiences" that are set by "one's current horizon of distinguishability", which in my view pretty much re-admits the core of what he's been arguing against (while clinging, a bit forlornly, to "current" to save face).