Alhough, under may circumstances, I could know approximately.
Agreed.
Bats have a sense that humans don't have, sonar, and if they have qualia, they presumably have some kind of radically unfamiliar-to-humans qualia to go with it.
I wasn't talking about sonar, but about good old-fashioned color perception. A bat's brain is very different from a human's. Thus, while you can approximate another human's perception fairly well, your approximation of a bat's perception would be quite inexact.
Identity theory does't explain qualia in the sense of explaining how variations in qualia relate to varations in brain state.
I'm not sure I understand what you mean. If we could scan a bat's brain, and understand more or less how it worked (which, today, we can't do), then we could trace the changes in its states that would propagate throughout the bat when red photons hit its eyes. We could say, "aha, at this point, the bat will likely experience something vaguely similar to what we do, when red photons hit our eyes". And we could predict the changes in the bat's model of the world that will occur as the result. For example, if the bat is conditioned to fear the color red for some reason, we could say, "the bat will identify this area of its environment as dangerous, and will seek to avoid it", etc.
If the above is true, then what is there left to explain ?
If the above is true, then what is there left to explain ?
Radically unfamiliar-to-humans qualia. You have picked an easy case, I have picked a difficult one. If we wan't to know what the world sonars like to a bat on LSD, identity theory doens't tell us.
[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.