I like mathematics because it is not human and has nothing particular to do with this planet or with the whole accidental universe - because, like Spinoza's God, it won't love us in return.

It is false to suggest that men must turn away from his desires in the interest of a higher duty. Men only responds to duty if he desires to do so. To understand men, you must understand their desires and the relative strength of those desires.

Love and knowledge, so far as they were possible, led upward toward the heavens. But always pity brought me back to earth. Echoes of cries of pain reverberate in my heart. Children in famine, victims tortured by oppressors, helpless old people a burden to their sons, and the whole world of loneliness, poverty, and pain make a mockery of what human life should be. I long to alleviate this evil, but I cannot, and I too suffer.

In America everybody is of the opinion that he has no social superiors, since all men are equal, but he does not admit that he has no social inferiors, for, from the time of Jefferson onward, the doctrine that all men are equal applies only upwards, not downwards.

[There are m]oral precepts that we consider really important, such as 'don't pick your nose' or 'don't eat peas with a knife'. There may, for ought I know, be admirable reasons for eating peas with a knife, but . . . early persuasion has made me completely incapable of appreciating them.

A word is used "correctly" when the average hearer will be affected by it in the way intended. This is a psychological, not a literary, definition of "correctness". The literary definition would substitute, for the average hearer, a person of high education living a long time ago; the purpose of this definition is to make it difficult to speak or write correctly.

Insight, untested and unsupported, is an uncertain guarantee of the truth.