We experience blue. And we can perceive our experience of blue. We know our experience is there and we know what we are experiencing. We can examine our visual experiences mentally since they persist as long as we maintain our gaze.
There is the perception of our experience of blue.
There is no perception of blue. It is not a thing that exists in the world.
Our memory is always available to us as limited as it is.
Even as we perceive our experience of blue.
A prisoner in solitary confinement without light or sound will hallucinate complete experiences of reality based solely on past experience, which are nothing more than correlated neural patterns.
Once we experience blue enough we can create the experience mentally. Blue becomes part of long term memory.
I can create the face of Santa Clause mentally too.
What does that prove besides I have experienced the face before?