We can’t identify "colors" in isolation either. Color is all relative. If a person had to identify the luminous intensity of a visual stimulus to within a factor of 2^(1/12) [the interval of one semitone], they wouldn't be able to do it. (With significant training and in standardized surroundings it could probably be learned by some people.) And precisely identifying hue/chroma in isolation is just as difficult.
(Note: there is no way to make a perfect analogy about sound vs. color identification, because the physical mechanisms and resulting perceptual spaces are completely different.)
(Note: there is no way to make a perfect analogy about sound vs. color identification, because the physical mechanisms and resulting perceptual spaces are completely different.)