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Protagoras comments on Three consistent positions for computationalists - Less Wrong
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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.
Well, then when she steps outside, her brain will be put into a physical state that it's never been in before, and as a result she will feel enlightened. This conclusion gives us no insight whatsoever into what exactly goes on during that state-change or why it's so special, which is why I think it's a stupid thought-experiment.
It isn't intended to answer your question about neuroscience.It is intended to pose the philosopher's question about the limitations of physicalism. If physicalism is limited, that eventually folds back to your question, since one way of explaining the limitation of physicalism is that there are non-physical things going on.
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.
Yes, clearly an experience can deliver knowledge. But does experience yield any additional knowledge over a simulation of same? One could plausibly argue that it does not.
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.
Sit on a brass tack. If you feel nothing, I will accept that the deifintion has no definiendum for you, even though it does for me and everyone else.
That reply would be cogent if I claimed not to feel pain. It not useful in this context, though, since I claim not to understand exactly what you do and don't mean by "qualia".
It does serve as a single example though. Provide a few dozen more, plus another few dozen examples of mental events that are not qualia, and a brief explanation of what it is that separates the negative and positive examples - do that and you will have communicated a concept. That is, you will have done so if no one disagrees with your lists and explanations and has a different understanding of the word 'qualia'.
Sometimes I wonder whether this is the reason that philosophers never produce such lists. When you read a text on thermodynamics, say, you will spend many pages going over the meanings of important technical terms like system, open, and closed. But, it is worth it because when you are done, everyone is on the same page. :)
Maybe this analogy is helpful: saying "qualia" isn't giving us insight into consciousness any more than saying "phlogiston" is giving us insight into combustion. However, that doesn't mean that qualia don't exist or that any reference to them is nonsensical. Phlogiston exists. However, in our better state of knowledge, we've discarded the term and now we call it "hydrocarbons".
The word "qualia" doesn't have to justify its existence by providing a solution. It can justify its use by outlining a problem.
Not really helpful (though I don't see why it deserved a downvote). It is not that I object to the term 'qualia' because I think it is a residue of discredited worldviews. I object to the term because I have never seen a clear enough exposition of the term so that I could understand/appreciate the concept pulling any weight in an argument.
And, as I stated earlier, I particularly object when philosophers offer color qualia as paradigmatic examples of atomic, primitive qualia. Haven't philosophers ever read a science book? Color vision has been well understood for some time. Cones and rods, rods of three kinds, and all that. So color sensation is not primitive.
And moving up a level from neurons to mind, I cannot imagine how anyone might suggest that there is a higher-level "experience" of the color green which is so similar to an experience of smell-of-mothballs or an experience of A-major-chord so that all three are instances of the same thing - qualia.