In the Shade

English has approximately one million words for different colours (I may be exaggerating a little, though only a little), and it's hard to tell what a clothing catalogue means when it tells you that a particular sweater is available in Fungus or Gasoline, but everyone knows the seven colours that are in the rainbow. I'm not even sure why we have any mnemonics for that list--it's so short and you can just memorize it--but "Richard of York gave battle in vain" and Roy G. Biv are the two I grew up with: red, orange, yellow, green, blue, indigo, violet.

We're so used to this that it seems natural, inevitable; obviously there are seven colours in the rainbow. And yet there aren't. There's no particular reason that we have a word for "green" and another for "blue" as if the two were mutually exclusive categories, as if there were a sharp dividing line between them. Head over here and do a search for "#0099AB"; what's that, blue or green? Both? Neither? Maybe it's teal, or turquoise, but if the colours of the rainbow have a literal meaning, then where does this colour fit? How about "#F54029"? Red? Orange? Scarlet, vermilion, russet? Where does it go?

The meanings of "blue" and "green" are nearly arbitrary. We stake out a chunk of the rainbow and say, "That's blue", but is it? Where does blue end and indigo begin? (And is indigo so different from blue, only darker?) We think of them as discrete categories--everyone knows that the leaves are green and the sky is blue--but it's easy to imagine a language in which colour isn't that important, in which there's only one word to cover the entire range of blues through greens, another that conflates red with orange and halfway through yellow. If this sounds preposterous, imagine a language in which there are even finer divisions between colours of the rainbow: perhaps this language has eleven strict colour names for what they see in the rainbow (they'd definitely need a mnemonic). Wouldn't they consider our language impoverished in that area? Wouldn't they claim that there are obviously eleven divisions, and that if we can't see them, there must be something wrong with our eyes?

There's an entire book on the subject (of course there is; there's an entire book on any subject you'd care to name), and you can read more about it here.