COLOR VISION
Chilean cognitive scientist, Francisco Varela (1991: 160) cautions that, for complex scenes, “there simply is no one-to-one relationship between light flux at various wavelengths and the colors we perceive areas to have.”
Two complimentary phenomena illustrate this:
1. Approximate color consistency refers to “the perceived colors of things remain relatively constant despite large changes in the illumination.”
2. Simultaneous color contrast or chromatic induction is when “two areas that reflect light of the same spectral composition can be seen to have different colors depending on the surroundings in which they are placed.”
Color vision is much more than a “perceived attribute of surfaces,” Varela (1991: 166) reminds us that we also generate color sensation from volumes like rainbows and the sky. We also experience color inwardly in “afterimages and in dreams, memories and synesthesia.”
Varela, Francesco. (1991) The Embodied Mind: Cognitive Science and Human Experience. MIT Press, Boston.
Chilean Neuroscientist and Philosopher [1946-2001]
American Philospher of Mind, Cognition and Evolutionary Biology
Modern Science—so goes the standard story—has removed the color from the physical world, replacing it with colorless electromagnetic radiation of various wavelengths, bouncing off surfaces that variably reflect and absorb that radiation. It may look as if the color is out there , but it isn’t. It’s in here —in the “eye and brain of the beholder.”Offering a parallel example, that can be found in most introductory biology texts, Dennett (1991: 379) muses that “facts about secondary qualities are inescapably linked to a reference class of observers.” Phenol-thio-urea tastes very bitter to around 25% of human beings, but it is as “tasteless as distilled water to the rest.” Obviously the primary quality—the specific chemical composition—of Phenol-thio-urea is unchanging and real. So too, is its secondary quality—the potential to elicit the sensation of bitterness in a class of perceivers endowed with the specific sensory equipment to do so. (The genetics of the “taster” phenotype can be found in any elementary biology text.) Dennett (1991: 371) makes a wry parallel with “the eternally popular puzzler about the tree in the forest that falls.” In the absence of an observer,“ [d]oes it make a sound?” Dennett leaves the reader ponder this.
Isaac Newton revolutionized the way we think about color. He championed the notion that color is in the mind of the beholder:
For the Rays to speak properly are not coloured. In them there is nothing else than a certain Power and Disposition to stir up a Sensation of this or that Colour... So Colours in the Object are nothing but a Disposition to reflect this or that sort of Rays more copiously than the rest; in the Rays they are nothing but their Dispositions to propagate this or that motion into the Sensorium…
Isaac Newton (1704) Opticks or A Treatise of the Reflections, Refractions, Inflections and Colours of Light. Book I, Part II. The Royal Society, London.
Kneller, Godfrey (1702) Detail of Sir Isaac Newton . Oil on canvas: feigned oval. National Portrait Gallery, London.
We assume that color is an objective property of objects in the world. In fact, the world is not colored at all. Color is a sensation in our heads. Objects certainly reflect different wavelengths of light. But electromagnetic radiation itself has no color.