Man's highly developed colour sense is a biological luxury - inestimably precious to him as an intellectual and spiritual being, but unnecessary to his survival as an animal. To judge by the adjectives which Homer puts into their mouths, the heroes of the Trojan War hardly excelled the bees in their capacity to distinguish colours. In this respect, at least, mankind's advance has been prodigious.

Mescalin raises all colours to a higher power and makes the percipient aware of innumerable fine shades of difference, to which, at ordinary times, he is completely blind. It would seem that, for Mind at Large, the so-called secondary characters of things are primary. Unlike Locke, it evidently feels that colours are more important, better worth attending to than masses, positions, and dimensions. Like mescalin takers, many mystics perceive supernaturally brilliant colours, not only with the inward eye, but even in the objective world around them. Similar reports are made by psychics and sensitives. There are certain mediums to whom the mescalin taker’s brief revelation is a matter, during long periods, of daily and hourly experience.

— The Doors of Perception and Heaven and Hell by Aldous Huxley (Page 24 - 25)