[0] Another subtlety here is that the brain states having structure isomorphic to something in subjectivity doesn't necessarily make sense. It would on the assumption that everything is 'structural', but that's not an assumption everyone is willing to make. (You can find demonstrations that mathematics and the sciences can only deal in terms of structure, which is why for their practitioners it makes sense to ignore anything non-structural—but this is very different from a demonstration that everything actually is structural.) In that case, in order to create this mapping, we have to create another structure (for instance, a taxonomy of colors names and relationships between colors), and we can configure that structure in a way which is intended to reflect some moments of subjective experience. Now that structure could be potentially be found isomorphic to some evolving brain states, while to say that the subjective experience itself was isomorphic is likely nonsensical.

I am reminded of an essay by Stephen Jay Gould, on the history of preformationism, and the debate over whether the homunculus resided in the sperm or the egg. The idea that a human could be represented by an ordering of simple chemicals was inconceivable at the time.

The idea that physicalism requires a specific physical locus for redness is no more sound than the idea that genetic theory requires human-ness to be located in a specific base on a DNA molecule. Emergent phenomena are real, common, and not, in general, particularly mysterious (though the mind certainly is, at least to me.)

More prosaically, maybe redness is actually localized, as a memory of a sensation. Is there anything more to redness than a comparison to prior sensations?

I have no issue with emergent phenomena. It's just that whether the phenomenon is emergent or not is irrelevant to the question at hand.

For instance, let's say the brain 'system' responsible for color perception is distributed all throughout the human brain in such a way that it would be impossible to formulate any hierarchical conceptual structure which could account for it. It's just an emergent consequence of a ton of other complex stuff going on.

Okay, now if you recall my previous point about reconciling the experience of redness vs clusters of neurons—you can hopefully see that the above makes no difference to the problem. It's just a different mapping of a physical structure onto subjective experience, without accounting for the fundamental difference between the subjective experience and the physical structure.

(This answer is less thorough, but I did take my time with what I wrote previously. If you read it more closely I think you'll see the difference in what we're each talking about here.)

If you insist that there is no difference, then it goes both ways. I think you are actually right in a way you did not intend: more sophisticated versions of the qualia argument are ultimately no better, as at some point, it always comes down to what you are prepared to believe - that there is a fundamental difference that cannot be bridged.

There was a time when humanity found it impossible to believe that life could arise from matter alone, yet dualism in this regard has effectively been abandoned, at least scientifically and philosophically. While this does not, of course, prove anything about the mind, it does show how arguments from the fundamental difference between matter and information-like things are really appeals to plausibility. As an observation that there is a gap in our understanding, that is fine; as a claim that the difference can never be resolved, they are just opinions.

And as I briefly speculated in my last paragraph, the physical basis for color as a quale might be surprisingly localized...

This including any kind of scientific hardware we use to measure it?

How many people believing otherwise would it take to change the experience of matter in general public, if it is subjective? (Because if it is subjective, it must be malleable.)

My teen self would call me a hippy - but you have to follow the logic!

wikipedia:

> Thus, the two kinds of knowledge, justification, or argument, may be glossed:

> A priori knowledge or justification is independent of experience, as with mathematics (3 + 2 = 5), tautologies ("All bachelors are unmarried"), and deduction from pure reason (e.g., ontological proofs).[3]

> A posteriori knowledge or justification depends on experience or empirical evidence, as with most aspects of science and personal knowledge.

There's nothing wrong or controversial about my definition. Non-Experiental Knowledge is Logical Knowledge by exhaustion. "Feeling" is exactly the kind of thing "a priori" was intended to exclude.

> In this sense it is similar to saying that something is axiomatic.

In no sense of the word, colloquial or academic, does "a priori" mean "axiomatic". They are different beasts.

> Besides I'm not at all sure there is a difference between knowledge gained from logic or from experience: <skims youtube video>

The video redefines the Problem of Infinite Regress as "Modus Morons". I've read What the Tortoise said to Achilles myself. Yes, the truth of modus ponens is arguably derived from induction. But that's a topic I'm not going to get into right now. At the very least, the terms are useful to label their disparate track-records.

If you want to dig further, your general position is called Idealism.

You have an argumentative style which implies that you are more interested in winning than seeking the truth. As such I am dissinclined to take you too seriously.

Similarly, suppose scientists discover a neural-structure (or chemical-interaction, etc) responsible for blueness. I can dissect it, electrocute it, soak it in LSD. But will the scientists experience blueness? No, because the structure isn't qualia per se.

The prevailing ideology is that by studying the mechanical nature of coffee machines, we'll ipso facto understand the biochemistry of the beverage. danielam is arguing that this ideology is probably wrong. This is why the Problem of Qualia is a problem.

Second -- and this is not the main thrust of what I said, but it is in response to what you wrote -- you are begging the question when you presume that everything can be accounted for physics. Consider the concept of Triangularity. In the world, we have concrete, triangular things that instantiate Triangularity. We perceive them through our senses. One triangle may be an isosceles triangle, another might be equilateral, still another may be a right triangle. Of these, each may be large, small, drawn with thick lines or quickly sketched on the board with a piece of chalk. However, none of these triangular things are themselves Triangularity or else only one triangle could exist. Furthermore, none of these concrete instances are perfect instantiations of Triangularity. The lines composing them are never fully straight. They are only approximations, and yet we still know what Triangularity is, its properties (like the angles summing to 180 degrees), and so on. It exists in our minds, and in the mind it exists, by necessity, completely apart from any particular, concrete instantiations of it (we may have images of triangles in mind, but the images themselves are not Triangularity itself, something all these images share). It follows that because Triangularity isn’t concrete or particular, there exists in the mind something that isn’t concrete or particular, but universal. But because physical things are necessarily instantiations of universals and not universals themselves, then we have in our minds something non-physical.