Thank you for the thoughtful reply. I'm still unable to see what the fuss is about. It is like deconstructing a candle and finding it is just an arrangement of carbon and hydrogen atoms, with a smattering of others and concluding that "candleness" is not an emergent property and therefor must be an extra-physical property.
Getting back to blueness, tons of experiments show that our perceptions are highly malleable and often inconsistent. If there is some extrinsic blue qualia, it sure seems to act like that qualia is modulated deeply by the physical aspects of the brain... so much so that it seems like there is no "platonic" qualia that needs to exist to explain the brain's perception of blue.
> tons of experiments show that our perceptions are highly malleable and often inconsistent
This is not something I deny. It is indeed true, as you say, "that qualia is modulated deeply by the physical aspects of the brain".
> concluding that "candleness" is not an emergent property
I think this isn't analogous, and I'll try to explain why. "Candle" is a word we made up, a convenient expression for a particular group of structures that we've decided to give a label to. Structures of kind 'candle' may exist in the world, and that's all there is to the story there. If you break this thing down, you no longer have that structure, and so no longer have a candle.
Qualia isn't like that. There isn't anything in the physical world corresponding to the 'blueness' in the world. There isn't a 'blueness' structure (there are wavelengths of light that correlate with me having an experience of blueness, but that isn't the blueness itself), and there isn't an object that is 'blueness'.
I don't know if this will help, but what I'm trying to point to here is 'blueness' as it is to us from the inside -- the experience of blueness. You can poke my brain in the right ways, and change my experience of blueness to be a different shade of blueness, or a different colour entirely. But the blueness itself, as it is to me in my experience, isn't in that materialist story.
You might talk about neurons, atoms, strings, fields, wavelengths, etc, but I don't see how to derive the blueness of my experience from talk about any of these things. With a candle, however, I can see where it is in the picture. We've agreed that candles are such and such structures, and so I can just look for those structures in the world and identify them. There's nothing to a candle above and beyond being a structure of the right sort.
Getting back to blueness, tons of experiments show that our perceptions are highly malleable and often inconsistent. If there is some extrinsic blue qualia, it sure seems to act like that qualia is modulated deeply by the physical aspects of the brain... so much so that it seems like there is no "platonic" qualia that needs to exist to explain the brain's perception of blue.