You can also know all relevant facts about physics but still not "know" how to ride a bicycle. "Knowing" what red looks like (or being able to imagine redness) requires your brain to have the ability to produce a certain neural pattern, i.e. execute a certain neural "program". You can't learn how to imagine red the same way you learn facts like 2+2=4 for the same reason you can't learn how to ride a bike by learning physics. It's a different type of "knowledge", not sure if we should even call it that.
Edit (further explanation): To learn how to ride a bike you need to practice doing it, which implements a "neural program" that allows you to do it (via e.g. "muscle memory" and whatnot). Same for producing a redness sensation (imagining red), a.k.a "knowing what red looks like".
Knowing" what red looks like (or being able to imagine redness) requires your brain to have the ability to produce a certain neural pattern, i.e. execute a certain neural "program"
Maybe. But, if true, that doesn't mean that red is know-how. I means that something like know-how is necessary to get knowlege-by-acquaintance with Red. So it still doesn't show that Red is know-how in itself. (What does it enable you to do?)
[Cross-posted.]
1. Defining the problem: The inverted spectrum
A. Attempted solutions to the inverted spectrum.
B. The “substitution bias” of solving the “easy problem of consciousness” instead of the “hard problem.”
2. The false intuition of direct awareness
A. Our sense that the existence of raw experience is self-evident doesn’t show that it is true.
B. Experience can’t reveal the error in the intuition that raw experience exists.
C. We can’t capture the ineffable core of raw experience with language because there’s really nothing there.
D. We believe raw experience exists without detecting it.
3. The conceptual economy of qualia nihilism pays off in philosophical progress
4. Relying on the brute force of an intuition is rationally specious.
Against these considerations, the only argument for retaining raw experience in our ontology is the sheer strength of everyone’s belief in its existence. How much weight should we attach to a strong belief whose validity we can't check? None. Beliefs ordinarily earn a presumption of truth from the absence of empirical challenge, but when empirical challenge is impossible in principle, the belief deserves no confidence.