I think colour is just a product of mental processes that occur when we take in information about our environment. The subjective experience of which we cannot explain in physical terms. (at least for now)
R.I.P Thomas Ashe
That is what colour is to us organisms with sensory organs, yes, but the electromagnetic spectrum isn't subjective.
"Need" is just a fiction. As is "should", "must", "value" and "importance".
I know but that's not what colour is.
R.I.P Thomas Ashe
The colours are the wavelengths of a small part of the electromagnetic spectrum our visual sensory organs can see. A colorblind person sees them differently than a non-colorblind person but they're there.
EDIT: There's a character in The Stars My Destination that only sees lower wavelengths than other humans and has named two of these colours "tang" and "burn". We can say "Oh, these colours are just what we call red and yellow!" but they might be blue and purple for all anyone else knows.
"Need" is just a fiction. As is "should", "must", "value" and "importance".
A colorblind person sees them differently than a non-colorblind person but they're there. The cerebral, nervous and sensory components stand out as more substantive than the "mental" as the OP refers to it.
shareSeems like you might be thinking of the emotions associated with particular colors rather than the colors in and of themselves, but perhaps. Color can be said to be a quality of material (solid, liquid, gas, plasma or so) and the absence of material, the qualities being organized into a table of combinations of a discrete set of electromagnetic wavelengths/bands which would be regarded as primary colors. And the purpose of perceiving color is just so that sensory input processor (e.g. the brain, particularly the cerebrum) can differentiate among groups of wavelengths/bands of the electromagnetic spectrum. Furthermore, machines can be made to "know" color.
shareAnd the purpose of perceiving color is just so that sensory input processor (e.g. the brain, particularly the cerebrum) can differentiate among groups of wavelengths/bands of the electromagnetic spectrum. Which is useful for discerning one object from another, might I add. It's not fool poof, but it does provide an animal with certain survival advantages.
shareA British spelling of Color?
shareWay to answer the title and ignore the post.
"Need" is just a fiction. As is "should", "must", "value" and "importance".