We have subjective experiences (SEs), which often mirror the outside world. But metaphorically speaking, we also have an “inner eye”.
For example, if I look at a black square table in a white room like this...
- The question “What do you see?”, I can answer with “A slightly reflective, black square table in a white room.”
- The question “What is your visual SE like?”, I might answer with “Roughly speaking, I experience a huge dark gray parallelogram with four dark gray parallel lines of similar length extending from its corners down vertically. All this, surrounded by white.”
This “inner eye”, which enables a partial answer by analogy to the second question, doesn't produce its own SE, there aren't any “second-level qualia”. It works in an immediate way (so “inner eye” seems like a misnomer, actually).
It is conceivable that the observation of the outer world could work in a way similar to how the “inner eye” informs us about our SEs – that is, immediately.
How SEs are produced by the brain is unknown, yet if we're materialists, we probably easily accept that SEs might not be “good for anything”. On the other hand, proponents of any non-materialist philosophy of mind more likely want to say something about what SEs might enable us to do.
So, did they? Are there any theories in this regard?