Well, in point of fact, I've personally never done LSD, so I don't know what color perception is like for another human on LSD, either. I could make an educated guess, though.
Normally I'd assume that I know what you meant and move on, but since this involves LSD... You don't know what it's like? Or you do, but it's an educated guess? What?
I've never done LSD myself, but I've talked to people who did, and I've read similar accounts in books, online, etc. Thus, I can make a guess as to what LSD would feel like, assuming my brain is close to the average.
[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.