Reply to Anil Seth:
Life Force: Many have responded to doubts about the possibility of explaining how and why organisms feel with doubts about the possibility of explaining how and why organisms are alive (suggesting that life is a unique, mysterious, nonphysical “life force”). Modern molecular biology has shown that the doubts about explaining life were unfounded: how and why some things are alive is fully explained, and there is no need for an additional, inexplicable life force. To have thought otherwise was simply a failure of our imaginations, and perhaps the same is true in the case of explaining how and why some organisms feel.
There is an interesting and revealing reason why this hopeful analogy is invalid: Life was always a bundle of objective properties (a form of “doing,” in the plain-talk gerunds of my little paper): Life is as life does (and can do): e.g., move, grow, eat, survive, replicate, etc., and just about all those doings have since been fully explained. Nor was there anything about those properties that was ever inexplicable “in principle”: No vitalist could have stated what it was about living that was inexplicable in principle, nor why. It was simply unexplained, hence a mystery.
But in the case of the mind/body problem, we can say (with Cartesian certainty) exactly what it is about the mind that is inexplicable (namely, feeling) and we can also say why it is inexplicable: (1) there is no evidence whatsoever of a “psychokinetic” mental force, (2) doing (the “easy problem”) is fully explainable without feeling, and (3) hence there is no causal room left for feeling in any explanation, yet (4) each of us knows full well that feeling exists. Hence the “hard” problem in the case of feeling is not based on the assumption there must be a non-physical “mental force” but on the fact that feeling is real yet causally superfluous.
(My guess is that what vitalists really had in mind all along, without realizing it, when they doubted that life could be explained physically and thought it required a nonphysical “vital force” was in fact feeling! It was actually the mentalism [animism] latent in the vitalism that was driving vitalists’ intuitions. Well, they were wrong about life, and they could never really have given any explicit reason in the first place for their doubts that living could not prove fully explainable physically and functionally (i.e., in terms of “doing”), just like everything else in nature. But with feeling we do have the explicit reason and it is not invalidated by the analogy with living. The important thing to bear in mind, however, is that the “hard” problem is not necessarily an “ontic” one. I don’t doubt that the brain causes feeling: I doubt that we can explain how or why, the way we can explain how the brain causes doing. The problem is with explaining the causal role of feeling, because that causal role cannot really be what it feels like it is.)
Feeling as Explanandum: I don’t think there’s any way for us to wriggle out of the need to explain how and why we feel (rather than just do) by an analogy with the fact that, say, physicists do not ask why the fundamental forces exist: We do not to ask why there is gravity; we just need to show how it can do what it does. If psychokinesis had been a fifth fundamental force, we could have accepted that as given too, and just explained how it can do what it does. But there’s no psychokinetic force. So it remains to explain how and why we feel, even though feeling, causally superfluous for all our doings, is undeniably there!
“Explanatory Correlates of Consciousness”: The only property of consciousness (a weasel-word) that is hard to explain is how and why anything is felt. The rest is “easy”: just an explanation of what our brains and bodies and mouths can do. Yes, the Turing Biorobot is the target to aim at. But it will not solve the hard problem — it won’t even touch it.
Conscious States = Felt States: Although the English word “feel” happens to be used mostly to refer to emotion and to touch, not only does it also feel like something to see, hear, taste, move and smell (in French “je sens” refers to emotion and to smell), but it also feels like something to think, believe, want, will, and understand. It is not “intentionality” (a weasel-word for the fact that mental [another weasel-word] states are “about” something or other) that is the mark of the mental, but the fact that mental states are felt states. Hence, apart from their “correlated” doings, “conscious states… convey meaning precisely because they are” felt. (The problem, as ever, is explaining how and why they are felt — rather than just done.)