I never held Negroes to be inherently inferior. The statement in Marriage and Morals refers to environmental conditioning. I have had it withdrawn from subsequent editions because it is clearly ambiguous.

Human nature is so constructed that it gives affection most readily to those who seem least to demand it.

The first dogma which I came to disbelieve was that of free will. It seemed to me that all notions of matter were determined by the laws of dynamics and could not therefore be influenced by human wills.

Whatever we know without inference is mental.

Zeno was concerned with three problems... These are the problem of the infinitesimal, the infinite, and continuity.

It seems to be the fate of idealists to obtain what they have struggled for in a form which destroys their ideals.

Some people would rather die than think.