It may be urged that diversities of opinion exist as to what good is. The convenience of the words "good" and "evil" corresponds to a need created by a common experience in the same way as the convenience of the words "light" and "darkness" does. A child might consider that a diamond generated light in the same way as a candle does. He would be mistaken, but this would not affect the correctness of his application of the word "light" to his experience; if he confused light with darkness he must immediately become unintelligible. Good and light are perceived and named--no one can say more of them; the effects of both may be described with more or less accuracy. To say that light is a mode of motion does not define it; we ask at once, What mode? And the only answer is, that which produces the effect of light. A man born blind, though he knew what was meant by motion, could never deduce from this knowledge a conception of light.
The Monthly Review, October 1902, "Rodin."
"Literary Remains of Albrecht Dürer," p. 177.
Ibid. p. 247.