Stevan Harnad is an accomplished professor, having founded and edited a respected academic journal, Behavioral And Brain Sciences. He is not a professional philosopher, but he has published articles related to cognitive science and he has a lot to say about feelings and consciousness. I've been engaging him in a discussion at the PhilPapers forum devoted to the explanatory gap. We've touched on side issues related to Descartes, skepticism, and categorization. I am continuing our discussion by email for now, at David Chalmers' suggestion. The following is the first of two emails I just sent Stevan. (The second email can be found here: "Discussion with Stevan Harnad, continued".)
David Chalmers has suggested that I take our discussion to email. I hope you do not mind. More and more of my point-by-point responses to you have been rejected by the editorial board (i.e., Chalmers) on the grounds that they are too long and too detailed to be of general interest to the forum members. (I don't have professional status, which is why my posts must pass review.) We can try to continue on PhilPapers, if you prefer, but I will not be able to address your points nearly as thoroughly as I would like. Or, if you like, we can move our discussion to another public forum of your choosing.
(This is why I have not responded to your most recent points about Descartes and skepticism. Twice I prepared responses, and both times they were rejected for being too long and detailed. I will send along the relevant content of those rejected posts in another email.)
SH: “When I say I lifted my finger because I felt like it, I am not talking about the functionality of my brain but about the causal power of my mind. Unpacked, that amounts to telekinesis.”
I don’t think this is a fair analysis of the common language. When people say they lifted their finger because they felt like it, they aren’t necessarily postulating mind/body dualism. They could well be talking about the functionality of their brain.
It still looks like you are confusing the sense and referent of the term "feelings." You say, (1) the referent of a feeling is the feeling itself, and (2) the sense of a feeling is what allows you to pick it out, which is the feeling itself. By your definition, the sense and referent is the same.
I understand the sense of the term "feelings" differently. It is not defined by any rules we have for directly picking out feelings. Rather, it is in the rules we have for picking them out indirectly, as causes of observable behavior. (E.g., How do you know you are in pain until you observe yourself reacting to something?)
You observe pain behavior, and interpret its cause as "pain." Thus we say "pain is felt," which only means "pain exists." There is no invariant feeling here, but rather a family resemblance of neural patterns which, due to similarities in observable behavior and a fair amount of fluidity in the common language, are indirectly referred to as “pain.” (Compare the pain of heartbreak with the pain of stubbing your toe. I wouldn’t assume there is an invariant feeling—or an invariant neural pattern—common to both.)
In everyday language, we talk about feelings as being felt. Yet, when we talk about those feelings in the language of neuroscience, as patterns of neural activity, we do not say they are felt. This does not mean the "feeler" is mysterious, or that the feeling is inexplicable. Rather, it means that the notion of "feeling" is dependent upon a certain ignorance of how human behavior actually works. It's not that feelings don't exist. It's just that our everyday language is not very good at picking them out. Your felt-functing/unfelt-functing distinction is thus a category error, a mistake made by taking categories from everyday language and assuming they apply to the language of neuroscience.
You can ask, "why are some neural patterns feelings, and others not?" That is like asking, "why are some chemical reactions distillation, and others not?" How you answer will depend on what you are trying to understand.
SH: “If you can categorize X's at all, you have to be able to detect whether an instance is or is not a member of the category X.”
Your point rests upon the supposition that, for all valid acts of categorization, all questions of membership presuppose a correct answer. Why make this supposition?
To categorize, you have to be able to decide whether an instance is or is not a member of the category. But that decision need not be based on a pre-existing criterion. You can just make one up. The only problem is when people assume that some criterion has to be there head of time, somewhere, hidden from view.
SH: “It matters not a bit whether you can categorize X's correctly by detecting that all X's are P and all non-X's are not-P or you can categorize X's correctly by detecting that all X's are "L or M or not-N or (more Q than R) or (if S then not-T)", otherwise they are not-X's. Just let P = "L or M or not-N or (more Q than R) or (if S then not-T)".
From this it follows that, for every P, there is an invariant Q which is shared by both P and NOT-P, where Q = (P or NOT-P). Doesn't this undermine the notion of an invariant?
SH: “What is uncomplemented is feeling itself, because there is nothing that non-feeling feels like; it is a contradiction in terms.”
If this claim makes sense, then the notion of “non-feeling” must make sense, too. Can we agree on that?
Consider the adjective, "special." It is possible that, whenever you categorize something as “special,” you are using a new criterion. This is not problematic or strange. It would not undermine the way we use the word “special.” In fact, we might think that our use of the term is in some ways dependent upon this possibility. (After all, when I ask you what is special to you, I am not asking about what has always been, or what will always be, special to you; but only about what is special to you now.) So there is no need to postulate an invariant here; and there is no need to think that there must be a correct way to categorize members of this set.
Thus it is with many adjectives in our common language. Must we draw a strong line between adjectives and nouns here? Isn’t it plausible that a number of nouns and noun phrases enjoy currency in our language, not because there is a set criterion of correctness, but precisely because there is none? Mightn’t “feeling” be such a noun, and "what it is like to be an X" such a noun phrase?
SH: “It could be (as Wittgenstein would point out), that this feeling I am (undeniably) feeling right now -- which feels to me like agony, and exactly like the agony I have felt before -- is not in fact the agony I felt before; indeed, perhaps I've never felt agony before; it only feels as if I've felt it before.”
That would be Kripke, not Wittgenstein. Wittgenstein’s aim was not to foster skepticism about how we categorize. On the contrary, it was (at least partially) to help us understand that we categorize on the basis of observable behavior, and that we should not assume that talk about “private sensations” is anything other than a grammatical convention.
It is not that doubt is impossible; rather, it is that doubt always has some motive, and we should never forget what it is that is calling some fact into question. Wittgenstein warned against doubt for the sake of doubt, or doubt for the sake of epistemological foundations.