The Colors

In 1665, the plague closed Cambridge for two years. Isaac Newton, who had just gotten his bachelors there, was stuck at home. To fill the time, he made a series of the biggest breakthroughs in physics, ever.

One of these regarded the nature of light and color. People knew that white light shined though a prism resulted in a rainbow of colored light, but they thought that the white light was perfectly pure and the colors were the result of the prism muddying the light. Well, Newton got a hold of two prisms. He used one to split the light, observed the different colored beams of light, and then tried to use the second prism to split one of the colored beams of light. If the prevailing theory was right, more colors should have been added, but no; it remained one color (red). Newton's new, correct, theory was that all colors are already present within the white light and the prism just separates them. In fact, he was able to use mirrors and lenses to recombine the separated colors back into white light. Incidentally, if you've ever heard of ROY G BIV you can thank Newton. He decided the colors of the rainbow were: Red, Orange, Yellow, Green, Blue, Indigo, and Violet. If indigo seems a bit awkward there, you're right. He just added it because he wanted there to be seven colors.

In fact, quite a few languages have done without "blue" entirely. If you ever read the ancient Greek Iliad and Odyssey you can count the usages of each color.  William Gladstone (the British politician) did just that and counted 170 uses of black, 100 of white, 13 uses of red, less than ten each of yellow and green, and not a single use of blue. Homer famously described the sea as "wine dark." If you read the Torah and New Testament in their original ancient Greek and Hebrew you'll, again, find no blue. In 1969 Berlin and Kay proposed a theory based on the study of dozens of languages suggesting that they always follow the same progression of adding color terms. A primitive language will only have black and white. Any dark or cool color will be lumped into black and any light or warm color will be white. If the language has three basic color terms, the next is always red. Then you get green and yellow, then blue. If you think about it, in a way blue is very rare in nature. It's by far the least common color in plants, animals, rocks, or dirt. It's the most difficult pigment to produce. But what about the sky, the sea? Well, we call those blue, but what about air, or water? They're clear, colorless. And these vast features are always background. One can imagine that if one had no concept of blue, no word for it, one could fail to really see that background. See this episode of Radiolab for a good discussion.