Franz Delitzsch, who put it most memorably when he wrote in 1878 that “we see in essence not with two eyes but with three: with the two eyes of the body and with the eye of the mind that is behind them. And it is in this eye of the mind in which the cultural-historical progressive development of the color sense takes place.”

Are the concepts of color directly determined by the nature of our anatomy—as Gladstone, Geiger, and Magnus believed—or are they merely cultural conventions?

Is it possible that people who could perceive colors just as we do still failed to distinguish in their language even between the most elementary of colors?

The belief in the inheritance of acquired characteristics was virtually universal until the mid-1880s.

everyone agreed on: that properties acquired during the lifetime of an individual could be inherited by the progeny.

His own answer was that it is highly unlikely that people with the same eyesight as us could nevertheless have made do with such strikingly deficient color concepts. And since it is so unlikely, he suggests that the only plausible explanation for the defects in the ancients’ color vocabulary must be an anatomical one.

Geiger, on the other hand, realized that the relation between the perception of color and its expression in language was an issue in need of addressing. “What could be the physiological state of a human generation,” he asked, “which could describe the color of the sky only as black? Can the difference between them and us be only in the naming, or i

Mankind’s perception of color, he says, increased “according to the schema of the color spectrum”: first came the sensitivity to red, then to yellow, then to green, and only finally to blue and violet. The most remarkable thing about it all, he adds, is that this development seems to have occurred in exactly the same order in different cultures all

Geiger went further than Gladstone in one other crucial respect. He was the first to pose explicitly the fundamental question on which the whole debate between nature and culture would center for decades to come: the relation between what the eye can see and what language can describe.