On Vision and Colors tried to demonstrate physiologically that color is "specially modified activity of the retina." The initial basis for Schopenhauer's color theory comes from Goethe's chapter on physiological colors, which discusses three principal pairs of contrasting colors: red/green, orange/blue, and yellow/violet. This is in contrast to the customary emphasis on Newton's seven colors of the Newtonian spectrum. In accordance with Aristotle, Schopenhauer considered that colors arise by the mixture of shadowy, cloudy darkness with light. With white and black at each extreme of the scale, colors are arranged in a series according to the mathematical ratio between the proportions of light and
On Vision and Colors the activity of the part that appears as color is necessarily conditioned by the inactivity of the complementary fractional part. The polar contrast between the active and inactive parts results in color. The vivid partial activity of the stimulated retinal spot is supported by that same spot's partial inactivity. Every color's darkness appears as its afterimage, or spectrum. Conversely, when looking at an afterimage, or physiological spectrum, the previously existing color is the darkening factor. Newton recognized that color is darker than white or light. He erroneously investigated light instead of the eye, the objective instead of the subjective. In