The history of color vision is closely linked to the Greeks' view of vision. In his late works (about 360 b.c.), Plato explained vision as a combined action of light from inside the eye and light from outside.⁹⁵ Thus, vision was for Plato a combination (synaugeia) of “outside” and “inside” light. Plato had the idea of a corpuscular emanation of light. Plato's theory can be abstractly explained as a close connection between the sensory organ (the eye) and the object. More than 2000 years later, Goethe, who was also very interested in color vision, wrote a poem based on Plato's theory:⁴¹

If the eye were not similar to the sun

It could not view the sun

Plato's theory is based on black, white, red and a quality best translated as “dazzling” or “sheen” (το λαµπρον), from which he believed all colors could be made. If you try to copy his mixtures, you will produce a result that is less multicolored than specified by Plato. Plato had most likely foreseen this and stated, “Who experiments in such a way, misjudges the difference between human and divine nature” and “to mix many into one and one back into many: for that only God has the wisdom.…”⁹⁵ We can perhaps see in that sentence a foreshadowing of Newton's realization that light exhibits many rays. But if we examine Plato's whole work, it becomes apparent that Plato believed that it is not the task of humans to examine nature and that no human will ever be able to understand nature. Aristotle³ strongly opposed Plato's attitude. For him, research into nature was very important. Aristotle defined color as the passive reception by the eye of an action originating in the object viewed. Thus, we can see Aristotle as the originator of scientific optics. Examining nature had for Aristotle and his successors the same value as thinking about God and the sky and was an abstract philosophy similar to discussion about the human soul. Aristotle mentions color when he speaks about the analysis of sensory perceptions. For him, the color on the surface of objects is an actual object of the sensory perception. He stated, “What can be seen in light is color.” Furthermore, Aristotle points to the white sun, which seems red if seen through the fog and smoke; thus, he addresses a feature that more than 2000 years later became for Goethe the elemental phenomenon of his “Farbenlehre.”⁴¹

Two thousand years after Aristotle, Newton experimented with the production and optimization of optical glasses. While doing this, he observed colored phenomena. These observations were for him the start of a research project about color that finally led to the experimentum cruces. On February 6, 1672, Newton wrote a letter to the Royal Society in London explaining his theories about light and color.⁹¹ He wrote, “Light consists of Rays differently refrangible. Colors are not qualifications of light, derived by refraction, or reflections of natural bodies (as generally believed), but original and cognate properties, which in divers rays are diverse.” His final point was “The color of natural bodies only shows the ability to light of a special ray more than others.” For Newton, white light in reality was the “most surprising and wonderful composition.” Further, he wrote that “white light is the usual color of light. For light is a confused aggregate of rays induced with all sorts of colors, as they are promiscuously darted from various parts of luminous bodies.” So “pure” white light, was an unordered mixture of colored rays! This epochal scientific approach was an enormous reversal of the direct sensory experiences. More than 100 years later, Goethe and Schopenhauer could not accept such ideas.^62,118