So let’s say this Alien eyes see on the infrared level, he would see normal RGB like you and I, but could be still know there is colors there? What reason is there for the alien to discover there is colors there?
I think I can’t imagine how we discover something that we don’t see, or mostly that there is something that I don’t know
“Color” is really just a conversion of certain wavelengths into something our brains can differentiate. However this theoretical alien differentiates between wavelengths of light would probably be different than us, just like we’re different than some other organisms on earth. If their method of differentiation is entirely different than “colors” we may not be able to conceptualize it, and they may not be able to conceptualize colors.
But just as an example, maybe they “feel” or “taste” different wavelengths of light instead of seeing them. We might be able to say, “hey, that light that you taste as sweet, we see as red”.
In their language they might have a way to describe that wavelength of light, just as we have a way to describe it, but our ability to really understand that description may not overlap.