[raphaelrk]

"In the province of the mind, there are no limits."

I do wonder to what degree this is true

There are claims that other animals see more colors than us. But what if that's not actually the case? Maybe conscious minds are only capable of seeing the same rainbow that we do

The mapping could be quite different, and even if you can't add more letters to "RGB" you can add more letters to "HSL", making things look neon, stereoscopic, brushed, iridescent, hyperbolic, etc. But perhaps what we see is already all the possible "base" colors?