we do all see roughly the same thing: we've got pretty much the same sensory organs & brains to process what is roughly the same data. It seems reasonable to expect that most members of a given species should experience roughly the same picture of the world.
To my disappointment, David Papineau concluded the same, but we can't compare differences in pictures of the world to differences in the brain structure or function because we can have only a single example of a "picture of the world." "Pretty much the same sensory organs & brains" is useless because of its vagueness.
So much for the first problem, at least in brief & from a pragmatic point of view. The skeptical philosopher must admit that this is a silly problem to demand a decisive answer to.
To the contrary, the qualia problem is exactly the sort of problem to which philosophy can provide a decisive answer. For example, that we can't frame the qualitative differences between persons conceptually should lead philosophers to doubt the coherence of the qualia concept.
Does perhaps the notion that innate concepts might be incoherent create confusion?
[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.