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Light may consist of a number of wavelengths in combination, all the way to white light which includes the whole spectrum of visible wave lengths. Light can be generated at its source (incandescence), or reflected so that the source light and the reflected light interact to determine color. Our eyes see light sources and reflected light entirely differently, as when the embers of a fire seem red in the dark, but gray when a light is shined on them.¹⁸⁰

Then there are the complexities of diffraction (the reason the day sky appears blue), transparency, luster, and luminosity.¹⁸¹ These are fundamentally different processes. In our commonsense experience, things are colored. In reality nothing is (simply) colored. Color is much more complicated than our immediate impressions seem to tell us. But it is not so complicated that we need to resort to the notion that it is an illusion, as Hardin suggests.^§MS1.3.1b

The mechanisms in our seeing mean that we only see to the extent that our (also very complicated) processes of mind allow us to see. In our retina, rod cells (120 million of them) detect light and dark. Three kinds of cone cells (7 million of them) detect color at just three peaks in the electromagnetic spectrum that seem to have no distinctive character as colors: at about 440nm (a bluish yellow), 530nm (a greenish yellow) and 560nm (a greenish red). Then, through a mechanism called opponent processing, combining the input from the three different kinds of cone cell, the mind figures colors from the combinations of spectral input.¹⁸²

Moreover, there is no reflectance profile, or measurement of wavelength on the electromagnetic spectrum, that reliably aligns with common colors – two yellows, for instance, may be indistinguishable to the eye, but with different reflectance profiles, though optical devices give us ways of distinguishing them.¹⁸³ Colors in these ways seem to be figments of our seeing, mind adding meaning to the limited spectral receptivity of the eye.

But receptive nevertheless our eyes are. Light is real; the eye offers affordances, albeit constrained, for its seeing; the mind processes its meaning into colors. Though the scientists agree that much is still to be learned about the neuroscience of color perception, this much we know, and this is surely enough to conclude that color is more than mere mental illusion.¹⁸⁴

We process light variations as brightness (dark to light), hue (color), and saturation (strength of hue). Sighted humans can distinguish about 2 million juxtaposed colors, and separately identify about thirty¹⁸⁵ – which means that if there are only eleven “basic” color terms,^§MS1.1.3a this is never enough. We also share our fundamental mechanisms of seeing with other animals in the natural world. Some animals – birds and insects even – can see more colors than us; others fewer.¹⁸⁶

There are also differences between sighted individuals, ranging from color blindness to the minor biophysical differences between individuals and among groups that one would expect in the realm of living things whose natural history proceeds on the basis of random mutation.¹⁸⁷ Notwithstanding these differences, there is cognitive constancy in the references humans make to color and historical consistency in the grammars of color within particular cultures.

Our minds make mental adjustments, composing constancy when the yellow color of a ripe lemon needs to be seen to be the same in sunlight, shadow, or under neon light. When a camera produces “bad” photos, we come to realize how different the light “really” is.

We also tell colors, not just by what they “are,” but in contrast by juxtaposition in space and successive contrast across time.¹⁸⁸ So, the sky may not be blue in the same way that a lemon is yellow, but in our shared, embodied, natural history we can tell that the sky is differently colored from a lemon, and a ripe lemon is differently colored from an unripe one. This is the existentially ordinary stuff of the chemistry of lemons and the physics of the biosphere. The chemistry, physics, and neuroscience are complicated perhaps, but nevertheless explicable.

These days, the carefully designed observational apparatuses of science allow us to “see” the electromagnetic spectrum beyond the immediate capacities of our eyes, both within and beyond the 380nm to 780nm range. Using media, today we can put to representational and communicative use the whole of the electromagnetic spectrum, hence the uses we have for X-rays, infra-red radiation, and radio. We can also see variation within the visible spectrum not visible to unmediated eye and mind.

We have, in other words, extended the affordance of vision well beyond the native capacities of the eye. This deeper and broader seeing is an artifact of history, no less than the artifacts of seeing evident in the grammar of color that Berlin and Kay uncovered,^§MS1.3.1a remarkable for their historically contingent differences and notwithstanding their claim to universalism.

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¹⁷⁹ Isaac Newton, 1730 [1952], Opticks, or a Treatise of the Reflections, Refractions, Inﬂections and the Colours of Light, New York, NY: Dover Publications, pp. 113–17; 161–65.

¹⁸⁰ M. Chirimuuta, 2015, Outside Color: Perceptual Science and the Puzzle of Color in Philosophy, Cambridge, MA: MIT Press, pp. 60–62.

¹⁸¹ C.L. Hardin, 1988, Color for Philosophers: Unweaving the Rainbow, Indianapolis, IN: Hackett Publishing Company, pp. 60, 63; T. van Leeuwen, 2011, The Language of Colour, London, UK: Routledge, pp. 34–37; 60–65.

¹⁸² C.L. Hardin, 1988, Color for Philosophers: Unweaving the Rainbow, Indianapolis, IN: Hackett Publishing Company, pp. 10, 26–36; Paul M. Churchland, 2010, “On the Reality (and Diversity) of Objective Colors: How the Color-Qualia Space Is a Map of Reflectance-Profile Space,” pp. 37–66 in Color Ontology and Color Science, Cambridge, MA: MIT Press, pp. 42–47; M. Chirimuuta, 2015, Outside Color: Perceptual Science and the Puzzle of Color in Philosophy, Cambridge, MA: MIT Press, p. 59.

¹⁸³ Paul M. Churchland, 2010, “On the Reality (and Diversity) of Objective Colors: How the Color-Qualia Space Is a Map of Reflectance-Profile Space,” pp. 37–66 in Color Ontology and Color Science, Cambridge, MA: MIT Press, pp. 38, 57.

¹⁸⁴ M. Chirimuuta, 2015, Outside Color: Perceptual Science and the Puzzle of Color in Philosophy, Cambridge, MA: MIT Press, pp. 59–62; Clyde L. Hardin and Luisa Maffi, eds., 1997, Color Categories in Thought and Language, Cambridge, UK: Cambridge University Press.

¹⁸⁵ C.L. Hardin, 1988, Color for Philosophers: Unweaving the Rainbow, Indianapolis, IN: Hackett Publishing Company, pp. 25–6; 88–9; Rolf G. Kuehni, 2010, “Color Spaces and Color Order Systems,” pp. 3–36 in Color Ontology and Color Science, edited by J. Cohen and M. Matthen, Cambridge, MA: MIT Press, pp. 4, 19.

¹⁸⁶ C.L. Hardin, 1988, Color for Philosophers: Unweaving the Rainbow, Indianapolis, IN: Hackett Publishing Company, p. 151; M. Chirimuuta, 2015, Outside Color: Perceptual Science and the Puzzle of Color in Philosophy, Cambridge, MA: MIT Press, p.4; Rolf G. Kuehni, 2010, “Color Spaces and Color Order Systems,” pp. 3–36 in Color Ontology and Color Science, edited by J. Cohen and M. Matthen, Cambridge, MA: MIT Press, p. 9.

¹⁸⁷ C.L. Hardin, 1988, Color for Philosophers: Unweaving the Rainbow, Indianapolis, IN: Hackett Publishing Company, pp. 78–80; Rolf G. Kuehni, 2010, “Color Spaces and Color Order Systems,” pp. 3–36 in Color Ontology and Color Science, edited by J. Cohen and M. Matthen, Cambridge, MA: MIT Press, p. 9; Kimberly A. Jameson, David Bimler, and Linda A. Wasserman, 2006, “Re-Assessing Perceptual Diagnostics for Observers with Diverse Retinal Photopigment Types,” pp. 13–34 in Progress in Colour Studies, Volume 2: Psychological Aspects, edited by N.J. Pitchford and C.P. Biggam. Amsterdam, NL: John Benjamins, p. 14; Marc H. Bornstein, 1973, “Color Vision and Color Naming: A Psychophysiological Hypothesis of Cultural Difference,” Psychological Bulletin 80 (4):257–85; Marc H. Bornstein, 1975, “The Inﬂuence of Visual Perception on Culture,” American Anthropologist 77(4):774–98; Melvin Ember, 1978, “Size of Color Lexicon: Interaction of Cultural and Biological Factors,” American Anthropologist 80(2):364–67.

¹⁸⁸ C.L. Hardin, 1988, Color for Philosophers: Unweaving the Rainbow, Indianapolis, IN: Hackett Publishing Company, pp. 49–51; M. Chirimuuta, 2015, Outside Color: Perceptual Science and the Puzzle of Color in Philosophy, Cambridge, MA: MIT Press, pp. 81–86.

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Cope, Bill, and Mary Kalantzis. 2020. Making Sense: Reference, Agency and Structure in a Grammar of Multimodal Meaning. Cambridge UK: Cambridge University Press, pp. 144-147. https://doi.org/10.1017/9781316459645

Isaac Newton’s Spectral Decomposition of Light §MS1.3.1c