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?