ABSTRACT
It is on the other hand difficult for me to suppose Aristotle could have made anything much out of Jeremy N athans's two reports. Even the concept of color blindness, which they explain through the idiom of modern molecular genetics, would not have been accessible to him. Any native speaker is equipped with a rich vocabulary of color terms-and when they are lacking one has recourse to "the color of . . ."— and there are always enough secondary cues that the color-blind can answer correctly questions about the colors of culturally familiar objects. There would have been no occupation in Aristotle's time which would make urgent the disqualification of color-blind candidates, as signal-light indiscrimination mandates their elimination as railroad engineers or ship navigators, or air traffic controllers-though they might have been slow hands in harvest time for raspberries, having difficulty in red-green discrimination. And beyond that, it is difficult to know what the concept could have meant without the apparatus of spectral colors. The first reference to color blindness is said to be in the Transactions of the Royal Society of 1684. The chemist John Dalton diagnosed himself as dichroma te in 1798, observing that whereas others required three primary colors to describe their chromatic array, he required but two. The misleading term "color blindness"— misleading because dichromates are not blind to the colors in question-replaced the more appropriate term "Daltonism " by which the relevant defect was long known (it may have been misleading if a description of dichromates by J. Scott preceded that of Dalton by twenty years).
