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Protagoras comments on Three consistent positions for computationalists - Less Wrong
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I wonder if I'm a qualia skeptic. I think that qualia are Humean impressions, the most "forceful and vivacious" contents of the mind. Dan Dennett has recently revived this view (without sufficiently crediting Hume, sadly); at one point he calls it the fame model of consciousness. What makes a thought conscious is that it does a lot; it has a very rich variety of interactions with other things going on in the mind.
This explains why there can be perception without consciousness; the much discussed (by philosophers) case of blindsight is an example where visual perception has a much more limited impact than usual, and so doesn't have enough force and vivacity (or fame or clout if you prefer Dennett's terminology, or whatever you want to call it) to feel conscious. And that's why something like the David Lewis "mad pain" case is probably possible; the range of different interactions a conscious experience has is sufficiently great that even something lacking one of the core functions of experiences of a certain type could still probably feel pretty much like that experience if it had enough of the right secondary connections.
I think I'm talking about qualia when I talk about these Hume/Dennett items. But I'm talking about things with certain kinds of functionally defined inputs and outputs, a certain kind of computations, in fact. Does this mean I am not talking about qualia as you mean them? If not, then I stand with perplexed; references to qualia should be committed to the flames, for they can contain nothing but sophistry and illusion.
Can you solve the "explaining colour to a blind man" problem with this proposal? I think not: vivid blue is just as famous and vivacious as vivid green, but that does not tell us what blue and green are...what their phenomenal feels are.
It is a little rude of you not to wait for me to answer before insisting that I can't. And it wouldn't hurt to be clear about what the problem is anyway. Color is extremely complicated, and most of the associations that make color perception conscious are not themselves conscious, so I personally certainly couldn't explain color to a blind man. But there's no problem there. And if someone did know enough about color to explain all the associations that it has, well, having associations explained to you isn't normally enough for you to make the same associations in the same way yourself, so perhaps it couldn't enable the blind man to imagine the color. But it's hard to say, and anyway, I don't know why he'd need to be able to imagine it to know what it was. I can say that when I've read articles about how echolocation works, and what sorts of things it reveals or conceals, I've felt like I know a tiny bit more about what it's like to be a bat than I did before reading the articles.
I think you are interpreting Peter's comment in an overly negative fashion. I believe he simply means "it seems that this proposal won't solve the problem of explaining color to a blind person" or something close to that.
I suppose you're right that I was a little snappy, but his response did seem to indicate that he wasn't really paying attention. Indeed, my response to him was too charitable; on rereading Peterdjones comment, he seems to have been responding to some straw-man view on which I claimed it was vividness that made green green, while I responded as if he'd tried to address my actual view (that vividness makes green conscious, and other functional characteristics make it green).
The claim that consciousness is fame in the brain, and the claim that qualia are incommunicable because of complexity are somewhat contradictory, because what is made famous in the brain can be subjectively quite simple, but remains incommunicable.
A visual field of pure blue, or a sustained note of C#, is not fundamentally easier to convey than some complex sensation. Whilst there maybe complex subconscious processing and webs of association involved in the production of qualia, qualia can be simple as presented to consciousness. The way qualia seems is the way they are, since they are defined as seemings. And these apparently simple qualia are still incommunicable, so the problem of communicating qualia is not the problem of communicating complexity.
Something that is famous in the brain needs to have a compelling quality, and some qualia, such as pains have that in abundance. However, others do not. The opposite of blindsight — access consciousness without phenomenal consciousness — is phenomenal consciousness without access consciousness, for instance "seeing something out of the corner of ones eye. Not only are qualia not uniformally compelling, but one can have mental content that is compelling, but cognitive rather than phenomenal, for instance an obsession or idée fixe; .
"And if someone did know enough about color to explain all the associations that it has, well, having associations explained to you isn't normally enough for you to make the same associations in the same way yourself, "
To some physicalists, it seems obvious that a physcial description of brain state won't convey what that state is like, because it doesn't put you into that state. Of course, a description of a brain state won't put you into a brain state, any more than a description of photosynthesis will make you photosynthesise. But we do expect that the description of photosynthesis is complete, and actually being able to photosynthesise would not add anything to our knowledge. We don't expect that about experience. We expect that to grasp what the experience is like, you have to have it. If the 3rd-person description told you what the experience was like, explained it experientially, the question of instantiating the brain-state would be redundant. The fact that these physicalists feel it would be in some way necessary means they subscribe to some special, indescribable aspect of experience even in contradiction to the version of physicalism that states that everything can be explained in physicalese.Everything means everything — include some process whereby things seem differnt from the inside than they look from the outide. They still subscribe to the idea that there is a difference between knowledge-by-aquaintance and knowledge-by-description, and that is the distinction that causes the trouble for all-embracing explanatory physicalism.
Weaker forms of physicalism are still posible, however.
"can say that when I've read articles about how echolocation works, and what sorts of things it reveals or conceals, I've felt like I know a tiny bit more about what it's like to be a bat than I did before reading the articles."
But everyone has the experience of suddenly finding out a lot more about something when they experience it themselves. That is what underpins the knowledge-by-acquaintance versus knowledge-by-description distinction.
I think that the "Mary's Room" thought experiment leads our intuitions astray in a direction completely orthogonal to any remotely interesting question. The confusion can be clarified by taking a biological view of what "knowledge" means. When we talk about our "knowledge" of red, what we're talking about is what experiencing the sensation of red did to our hippocampus. In principle, you could perform surgery on Mary's brain that would give her the same kind of memory of red that anyone else has, and given the appropriate technology she could perform the same surgery on herself. However, in the absence of any source of red light, the surgery is required. No amount of simple book study is ever going to impact her brain the same way the surgery would, and this distinction is what leads our intuitions astray. Clarifying this, however, does not bring us any closer to solving the central mystery, which is just what the heck is going on in our brain during the sensation of red.
To say that the surgery is required is a to say that there is knowledge not conveyed by third persons descriptions, and that is a problem for sweeping claims of physicalism. That is the philosophical problem, it is a problem about how successful science could be.
The other problem, of figuring out what brains do, is a hard problem, but it is not the same, because it is a problem within science.
No it isn't. All it says is that the parts of our brain that interpret written language are hooked up to different parts of our hippocampus than our visual cortex is, and that no set of signals on one input port will ever cause the hippocampus to react in the same way that signals on the other port will.
But if physicalism is correct, one could understand all that in its entirety from a third person POV, just as one can understand photosynthesis without photosynthesising. And of course, Mary is supposed to have that kind of knowledge. But you think that knowledge of how her brain works from the outside is inadequate, and she has to make changes to her brain so she can view them from the inside.
The very premise of "Mary is supposed to have that kind of knowledge" implies that her brain is already in the requisite configuration that the surgery would produce. But if it's not already in that configuration, she's not going to be able to get it into that configuration just by looking at the right sequence of squiggles on paper. All knowledge can be represented by a bunch of 1's and 0's, and Mary can interpret those 1's and 0's as a HOWTO for a surgical procedure. But the knowledge itself consists of a certain configuration of neurons, not 1's and 0's.
No, the premise of the Mary argument is that Mary has all possible book-larnin' or third person knowledge. She is specifically not supposed to be pre-equipped with experiential knowledge, which means her brain is in one of the physical states of a brain that has never seen colour.
No, she is not going to be able to instantiate a red quale through her book learning: that is not what is at issue. What is at issue is why she would need to.
Third person knowledge does not essentially change on translation from book to paper to CD, and for that matter it should not essentially change when loaded into a brain. And in most cases, we think it doesn't. We don't think that the knowledge of photosyhtesis means photsynthesising in your head. You share that the qualiaphobes assumption that there is something special about knowledge of qualia that requires instantiation.
You're converting "physicalism" from a metaphysical thesis to an epistemological one, or at least adding an epistemological one. That's not the usual usage of the term.
Since qualia are widely supposed to impact physicalism, and since they don't impact ontological theses such as "everthing is material", then it is likely that people who suppose that way have the descriptive/explanatory/epistemological version in mind, however implictly.
I don't understand how Mary's room is supposed to be epistemologically relevant. Supposing that physicalism is true (and that physics is computable, for simplicity) Mary can run a simulation of herself seeing red and know everything that there is to know about her reaction to seeing red, including a comprehensive description of its phenomenology. Yet, she will still lack the subjective experience of seeing red. But this lack has nothing to do with epistemology in the first place.
It does have something to do with epistemology, because the experience delivers knowledge-by-acquaintance, which is a form of knowledge.
I think this does get at one of the key issues (and one of the places where Hume was probably wrong, and Dennett constitutes genuine progress). On my theory, qualia are not simple. If qualia are by definition simple (perhaps for your reason that they seem that way, and by definition are how they seem), then I am a qualia skeptic. Simple qualia can't exist. But there is independent reason for being skeptical of the idea that phenomenal conscious experiences are as simple as they appear to be. Indeed, Hume gave an example of how problematic it is to trust our intuitions about the simplicity of qualia in his discussion of missing blue, though of course he didn't recognize what the problem really was, and so was unable to solve it.
Given that qualia ere what they appear to be., are you denying that qualia can appear simple, or that they are just appearances?
As I have already argued, it is not the case that everything is functional or has a functional analysis off the bat: that cannot be assumed apriori. I cannot see the functiona analysis of a blob of chewing gum or a magnetic field. Funcitonal things need well defined inputs, well defined outputs, and a well-defined separation between them and its inner workings,
Since funtionalism is not a universal apriori truth, I see no reason to "codemn to the flames" any non-functional notion of qualia.
I think we know what qualia are because we have them, But that is knowledge-by-acquaintance. It is again question-begging to say that the very idea of qualia has to be rejected unless they can be described. The indescribability of qualia is the essence of the Hard Problem. But we cannot say that we know apriori that only describable things exist.
Unpack this. You know what your qualia are because you have them. I know what my qualia are because I have them. We come to use the same word for these impressions ... why, exactly?
What was it Wittgenstein said about remaining silent?
We also both call our kidneys kidneys. I don't see the big deal.
I didn't realise Witt was 100% correct about everything.
Only because we are able to describe our kidneys.
I can describe qualia in general as the way thing seem to us. I can't describe them much more specifically than that.
I don't believe so. I'll accept that you can describe them as the way things seem to you. Or define them as the way things seem to us. What I am saying is that you cannot convince me that the definition has a definiendum unless you get more specific. Certainly, your intuitions on the significance of that 'seeming' have no argumentative force on anyone else until you offer some explanation why they should know what you are talking about.
Commit the references to the flames, but not the referees? You are no fun! :) Though since you have invited Hume to join us, I suppose I am satisfied.
Your mention of qualia and functionality in the same paragraph caught my attention. Yes, indeed. If qualia were not functional, then they could hardly be intersubjective. And if they are functional, why the instinctive appeal of the idea that the inimitable 'essence' of qualia can not be generated by a simulation?
I don't understand you comment about intersubjectivity. Qualia surely are not intersubjective in the sense of being publically accessible. If you just mean that qualia are broadly the same between people under she same circumstances, then that is given by supervenience, which AFAICS has nothing to do with functionalism.
I am philosophically unschooled, so I may misunderstand "supervenience". I will take it to mean, roughly, that distinct instances of the same phenomenon will have features in common. Yes, but how do we know we are talking about different instances of the same phenomenon unless they have the same function. Cartoon dialog:
Joe: I feel something.
Mary: I feel something too.
Joe and Mary: We both feel the same way.
One doesn't have to be a very strong skeptic to suspect that that third step was something of a leap. But perhaps less of a leap if what they feel is nausea after eating at the same restaurant.
We can say that the qualia will be the same if their supervenience bases are the same, and we can say that if they have the same properties. Non functional things like blobs of chewing gum still have properties.
Yes, and we determine those properties using senses that exist because, in other contexts, their use is functional. Do we have a 'sense' that detects the presence of qualia and apprehends their properties? If we do have such a sense organ, would you care to speculate on its function or lack of function?
I'm using functional to mean "something that has inputs, outputs, and internal workings", not to mean "something that does something somehow".
I don't think we have such a sense. More importantly, nothing I have said implies it.
Ah! I was using it in the biological sense. As roughly the same as "purpose". (You are, of course, welcome to add as many additional scare quotes as you think necessary to immunize us from the taint of teleology.)
It appears we have been talking past each other. This may be a good place to stop.