"brain-imaging studies... demonstrate in ever more detail how specific kinds of mental activity (as reported by a mindful subject) are precisely correlated with specific patterns of brain activity (as recorded by external instruments).(Humphrey 2000)"

But the Mind/Body Problem (M/BP) is about causation not correlation. And its solution (if there is one) will require a mechanism in which the mental component somehow manages to play a causal role of its own, rather than just supervening superflously on other, nonmental components that look, for all the world, as if they can do the full causal job perfectly well without it (thank you very much). Correlations confirm that M does indeed "supervene" on B, but causality is needed to show how/why M is not supererogatory; and that's the hard part.

Nick Humphrey's heroic attempt is informative -- and some of it might even be correct, functionally speaking -- but alas it too fails to furnish the missing causal link for the mental component, which continues to dangle in his account, nonfunctionally. Hence the only problems Humphrey solves are the "easy" ones, not the M/BP.

"suppose, by analogy, that... "atmospheric-imaging" experiments [demonstrate] that whenever there is a visible shaft of lightning in the air there is a corresponding electrical discharge. We might soon be confident that the lightning and the electrical discharge are aspects of one and the same thing"

Empirically detectable shafts of lightning and empirically detectable electrical discharges are the same kind of thing (empirical data, detectable by instruments). So are empirically detectable brain activities and empirically detectable behaviour and circumstances. So when I say or act out that something hurts (especially when something is indeed damaging my tissues), and the accompanying brain-image is neural activity in my nociceptor system, we do have a correlation between things of the same kind, exactly as in the case of the lightning. And out of that correlation we can contruct a causal theory of nociceptive function (tissue injury, avoidance, learning, recall, etc.).

But when the correlate in question is my feeling of pain, we're in another ballpark: There's now an explanatory gap that neither the nociceptive theory (which is only a functional theory of tissue-damage-related doing) nor any amount of reconfirmation of the tightness of the correlation can close.

So maybe what Humphrey means to highlight in the lightning case is not the correlation between the two sets of empirical data, but between the empirical data and an underlying causal factor that explains the data. That's fine too, but then the analogy with M/B correlations in imaging is irrelevant, and we are talking about a causal explanation: And if so, what IS that underlying causal factor in the case of the M/BP? All I see is unexplicated correlations. (Note that the neural functions and the behavioral functions and their interrelations do get explicated, but their mental correlations do not.)

Nor is it a matter of "deducing one from the other a priori" (even physics doesn't do that, only mathematics does). The "laws" of physics are not necessary but contingent; so are their boundary conditions. So this is a red herring. The real problem is about causal explanation in the special case of M/B. Consciousness seems fated to be a causal dangler no matter how tight the coupling and how minute the predictability. It's like perfect weather-forecasting without the underlying meteorological theory.

(Remember: Neural and behavioral functions are not at issue; mental ones are. The correlations of a purely behavioral neuroscience would not be problematic in any way; it's the causal status of the mental component that is at the root of the M/BP. The causality in M/B theory is invariably "third-party" causality: The underlying neural mechanism causes both the brain/body's functional neural/behavioral states and the fact that they happen to be mental states. The trick is to show -- functionally, if that's the route one elects to take -- how/why the mentality is not functionally superfluous; just reaffirming that its causally hard-wired somehow to its functional substrate is not an answer.)

"with lightning [t]he physico-chemical causes that underlie the identity [were] discovered through further experimental research and new theorizing. Now the question is whether the same strategy will work for mind and brain."

Humphrey wishes to distance his own position from two nonstarters, those of Chalmers (1996) and McGinn (1989):

"Chalmers [1996]... argues [that] consciousness just happens to be a fundamental, non-derivative, property of matter."

"McGinn [1989] believes that... certain kinds of understanding... must for ever lie beyond our intellectual reach [e.g., the M/BP]."

Nor is it clear why in his own approach Humphrey wants to obscure the M/BP with formalism ("dimensions," "equations," "identities")? The problem is clear, hard, and staring us informally in the face: I have feelings. Undoubtedly the feelings are in some way caused by and identical to ("supervene on") brain process/structures, but it is not at all clear how, and even less clear why. That's the M/BP. No "equation" to write down; no "terms." And the "incommensurability" is the name of the game (or of the problem)!

Inputs and outputs can be connected, functionally, computationally. But feelings are another story (a hard one!). If we "characterize" feelings computationally or functionally, we have simply begged the question, and changed the subject -- to a discussion of the relation between brain function and computational (or other) function.

"Most of the states of interest to psychologists... remembering, perceiving, wanting, talking, thinking, and so on are... amenable to... functional analysis."

"recalling that today is Tuesday = activity of neurons in the calendula nucleus.... But [these] are notoriously the "easy" cases... No one it seems has the least idea how to characterize the phenomenal   experience of redness in functional terms"

In reality, every mental capacity has both an easy and a hard aspect: the functional aspect is easy, the feeling aspect is hard. But it's the feeling aspect that makes it mental! So there's only one M/BP, and that's the hard one. The rest is just mindless Zombie functionalism (a branch of reverse bioengineering that is not particularly "easier" empirically than any other area of science).

Now we arrive at what will be the core insight, which Humphrey attributes to Reid:

"sensory awareness is an activity. We do not have pains we get to be pained. This is an extraordinarily sophisticated insight [of Reid's]"

No illumination follows from adopting these distinctions. YES some of the sceptical problems (not induction, but definitely solipsism and other-minds) are lemmas of the M/BP. But the M/BP is primary. Solve that and those bits of idealism will be trivial by comparison (and will probably vanish).

But don't try to subordinate the (unsolved) theorem to the derivative lemma! Never mind the distinction between trees and moods: For M/B purposes they are completely of a muchness, and moods are the more representative case, rather than the external-world-contingent special case of trees.

To put it another way: it is the relation between feelings and brain states that we are charged with explicating, not the relation between feelings and their objects whether internal or external (i.e., "feeling that I am seeing a blue balloon" vs. "feeling [affectively] blue"). All such cases are equally symptomatic of and infected with the M/BP; to try instead to resolve some of the differences that distinguish them from one another them is just to change the subject and beg the question (and analogous to focusing on differences in notation instead of confronting their common content, except that here it is qualitative content differences that are distactctng us from the problem --which is that there esists any content at all!)).

"my own view... is that the right expression is not so much "being pained" as "paining"... sensing is not a passive state at all, but... active engagement with the stimulus occurring at the body surface."

And let us quickly lay to rest what might have looked as if it too were a contender for a phenomenological category of its own, along with seeing trees vs. feeling pains: performing a volitional act (e.g., lifting my finger). No help there either. When I lift my finger, it feels-like "me-deliberately-finger-lifting." Just another feeling to account for, along with all the others. The fact that it feels-like I'm doing it, rather than like it's being done-unto me amounts to just one more (irrelevant) difference in feeling content. It does not give us any leg up on the M/BP.

Efference is a red herring here. It feels-like I'm being the agent, and maybe that's correlated with efferent brain activity: yet another correlation. (Humphrey's proposed "Sentition" is even worse. We don't need new terms! We need conceptual insights -- if there are any to be had.) I too happen to have a longstanding interest in the motor component of perception (Harnad 1982). But there are no inroads to the M/BP from any of that -- just perhaps true and interesting functional facts about the relation between afference and efference, reafference, reflexive vs. nonreflexive behavior, motor theories of perception, etc.

One also cannot agree with Humphrey that "it is 'like something' to have sensations, but not like anything much to engage in most other bodily activities!" Kinesthesia is qualitative; so is the difference between what it feels-like to raise your leg when it has been tapped on the patella by a doctor vs. when you will the motion deliberately. Those are all differences in "Feeling Space" -- just like everything else (including mental imagery and mental reasoning, indeed all of the "language of thought"). But this casts no light on the M/BP.

Humphrey's "self-resonance" sounds like just another one in the long litany of "self-X" terms meant to illuminate consciousness (self-awareness, self-reference, self-representation, etc.) -- while in reality merely renaming it.

(I might add that the "self" need not figure in it at all: The concept of the "self" -- though, like everything, it has its qualitative contents -- surely came late in the evolutionary day. The amphyoxus already has a full-blown M/B problem, even though it does not know it, if it aches when you pinch it, and that's the only experience that ever goes on in there -- no Cartesian reflection on its being my ache, and me as distinct from it as the patient of that sensation, etc. But just that ache is feeling enough; no "self-resonance" needed...)

Similarly, the fact that an "animal has a defining edge to it, a structural boundary" sounds like an excellent functional/Darwinian reason for evolving mechanisms that make the inner-outer distinction, and act upon it. But why should any of that feel like anything? Why must one not be a zombie-amoeba in order to get the full functional benefits Humphrey describes in his evolutionary scenario? (As usual, there is some conflation of the mental and the internal here.)

Organisms "must evolve the ability to sort out the good from the bad and to respond... with an ow": Humphrey is here caught in the act of cognostic contraband, smuggling in a feeling reaction (otherwise what does the "ow" mean?), where all that was needed functionally was a doing one. Question duly begged.

Similarly with "When red light falls on it... it wriggles redly.": Why should that feel like anything? And if it doesn't, then it's just wriggling wrigglingly, under red conditions. Once one has cheated, and allowed any qualitative light to enter into and "quicken" what should merely have been functional/Darwinian survival/reproduction machines -- Zombie ones, as plants are [I hope, being a vegeterian who tries not to eat anything that has or has ever had qualia!] -- generating the mental stuff one has set out planning to explain, the game is over and the M/B question is begged! Why/how do they wriggle feelingly rather than merely doingly?

"as yet, these sensory responses are nothing other than responses... no reason to suppose that the animal is in any way mentally aware of what is happening."

"as this animal's life becomes more complex, the time comes when it will indeed be advantageous for it to have some kind of inner knowledge of what is affecting it, which it can begin to use as a basis for more sophisticated planning and decision making. So it needs the capacity to form mental representations of the sensory stimulation at the surface of its body and how it feels about it."

"By monitoring its own responses, it forms a representation of 'what is happening to me'."

"wouldn't it be better off if, besides being aware of feeling the pressure wave as such"

"able to interpret this stimulus as signaling an approaching predator?"

It should be clear by now that Humphrey has gotten out of this exactly what he has put into it. His language and caveats are equivocal about precisely where, how, or why he has smuggled in the light of consciousness (or the warmth of feelings), but clearly at some point he has, and we are meant to go along with this.

Alas, I cannot, because Humphrey has given me no reason -- functional or logical -- for doing so. He has simply arbitrarily turned on the mental lights at some juncture, and somehow attributed that to the Darwinian story he was telling; yet the story (except as a Just-So story. i.e., as mere hermeneutics) does not explain or justify it at all.

"When the question is "what is happening to me?", the answer that is wanted is qualitative, present-tense, transient, and subjective. When the question is "what is happening out there?", the answer that is wanted is quantitative, analytical, permanent, and objective."

It is conceivable that two systems evolved along the lines Humphrey describes; it is even conceivable that there are some correlations between his functional account and consciousness (although even functionally some parts seem problematic).

But the part Humphrey owes us, if this is really meant to have any bearing on the M/B problem, is an explanation of when/how/why feelings kicked in (whatever their correlation with these two hypothetical systems might be).

"proto-experience of sensation arises from its monitoring its own command signals for these sensory responses."

"though the animal may no longer want to respond directly to the stimulation at its body surface as such, it still wants to be able to keep up to date mentally with what's occurring"

Humphrey's closed-circuits and internal loops are also popular candidates for "self-X" structures/processes (self-modifying and self-organizing are others), but all of these are too easy! One cannot just baptize them as "mental" and declare that a problem has been solved. It is the simplest thing (and indeed valid, because of the M/B correlation) to give a mentalistic interpretation to certain brain processes. But to interpret them as mental (even truly so) is not to explain them (causally) as mental! Such are the limits of mentalistic hermeneutics Harnad 1990a, b).

"Now once this happens [natural] selection is no longer involved in determining the form of these responses and... the quality of the representations based on them."

I never quite figured out what Humphrey's "thickness factor" was (perhaps there was something intentionally Geertzian about it [Geertz 1973]) -- apart from the fact that it appears to be making some sort of a continuum out of something that is all or none: Either feeling is going on or it is not; if it is, then we are again just haggling about the price; but Humphrey owes us an explanation of how/why the feeling-switch was turned on at all in the first place.

"when the process becomes internalized and the circuit so much shortened, the conditions are there for a significant degree of recursive interaction to come into play... the command signals for sensory responses begin to loop back upon themselves, becoming in the process partly self-creating and self-sustaining... they have... become signals about themselves."

Reply to Humphrey's Reply:

 
HUMPHREY: Sometimes, I confess, that when faced with the only-up-to-a-point functionalism of van Gulick or de Quincey or most of my colleagues, I am almost relieved to come across the unrepentant in-your-face anti-functionalism of Stevan Harnad. At least with Harnad you know where you are.

With this problem, you either solve it or you don't; no half-way houses on the hard road to consciousness.

And it won't do to dismiss me as an antifunctionalist either! I am a functionalist -- for the doable part, which is the "easy" problem (though no easier than the rest of science), namely, the reverse-engineering of the brain's capacity for doing. It is the hopeless, hapless tilting at the hard problem of feeling, with functionalism as a lance, that I am afraid I must continue to decline as having absolutely no explanatory power for me...
 

HUMPHREY: The sarcasm is transparent: `I can design and implement recursive self-sustaining loops fitting Humphrey's description easily. Do they quicken with the light of consciousness?' No of course not, because: `If we "characterize" feelings computationally or functionally, we have simply begged the question, and changed the subject'. Functionalism for Harnad is by definition 'zombie functionalism'.

Not quite by definition; by default. I'm ready to add feelings the minute there is a FUNCTIONAL call for them; but as long as the feelings are merely decorative or hermeneutic or "supervenient," as long as there is no reason at all that the functions cannot take care of all the doings feelinglessly, the hard problem remains intact.
 

HUMPHREY: But, if I am glad to have Harnad state the enemy's case so boisterously and scornfully as he does in his commentary, it's only because he thereby reveals the ultimate vacuity of his position. It goes nowhere. It makes no predictions. It generates no tests. Indeed, for Harnad it would actually be an argument against the legitimacy of any theory of consciousness that someone should even imagine that his theory could be tested by implementing the consciousness-producing architecture in a machine. Because if he were to interpret anything the machine actually does with its new architecture (anything at all) as evidence that the implementation has been successful, that would only show that his theory begged the question.

HUMPHREY: It's as though Harnad has managed to turn Tertullian's grand claim 'I believe because it is impossible' into its corollary 'I do not believe because it is possible'.

(Note again that it is not in the existence of feelings, nor even in the presence of feelings in the successful functional implementation, that I disbelieve, but in the success of Humphrey's  functional explication of feelings, i.e., his putative solution to the MB/P.)
 

HUMPHREY: Of course this was also the ultimate argument used against Darwin. It may be true, the churchmen said, that it would have been possible for the living world to have been designed by natural selection. But don't be fooled. God has arranged things to appear as-if designed by natural selection, just so as to test your faith in the fact that they have not really been so designed.

HUMPHREY: A hundred and fifty years later no one can be bothered with such sophistry. And there's a moral there.

REFERENCES

Geertz, C. (1973) The interpretation of cultures; selected essays. New York, Basic Books

Harnad, S. (1982) Consciousness: An afterthought. Cognition and Brain Theory 5: 29 - 47. http://www.cogsci.soton.ac.uk/~harnad/Papers/Harnad/harnad82.consciousness.html

Harnad, S. (1990a) Against Computational Hermeneutics. (Invited commentary on Eric Dietrich's Computationalism) Social Epistemology 4: 167-172. http://www.cogsci.soton.ac.uk/~harnad/Papers/Harnad/harnad90.dietrich.crit.html

Harnad, S. (1990b) Lost in the hermeneutic hall of mirrors. Invited Commentary on: Michael Dyer: Minds, Machines, Searle and Harnad. Journal of Experimental and Theoretical Artificial Intelligence 2: 321 - 327. http://www.cogsci.soton.ac.uk/~harnad/Papers/Harnad/harnad90.dyer.crit.html

Harnad, S. (1994) Levels of Functional Equivalence in Reverse Bioengineering: The Darwinian Turing Test for Artificial Life. Artificial Life 1(3): 293-301. Reprinted in: C.G. Langton (Ed.). Artifial Life: An Overview. MIT Press 1995.
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Harnad, S. (1995) Why and How We Are Not Zombies. Journal of Consciousness Studies 1: 164-167. http://www.cogsci.soton.ac.uk/~harnad/Papers/Harnad/harnad95.zombies.html

Harnad, S. (2000) Turing Indistinguishability and the Blind Watchmaker. In: J. Fetzer & Mulhauser, G. (eds.) "Evolving Consciousness" Amsterdam: John Benjamins http://www.cogsci.soton.ac.uk/~harnad/Papers/Harnad/harnad98.turing.evol.html

Harnad, S. (2001) Minds, Machines, and Turing: The Indistinguishability of Indistinguishables. Journal of Logic, Language, and Information (JoLLI) special issue on "Alan Turing and Artificial Intelligence" (in press)
http://www.cogsci.soton.ac.uk/~harnad/Papers/Harnad/harnad00.turing.html

Humphrey, N. (2000) How to Solve the Mind-Body Problem"] Journal of Consciousness Studies 7.
http://cogprints.soton.ac.uk/abs/phil/200002001

Nagel, T. (1974) What is is like to be a bat? Philosophical Review 83: 435-451.

Nagel, T. (1986) The view from nowhere. New York: Oxford University Press