“Sanity is a madness put to good uses.”

“The mass of mankind is divided into two classes, the Sancho Panzas who have a sense for reality, but no ideals, and the Don Quixotes with a sense for ideals, but mad.”

“The need of exercise is a modern superstition, invented by people who ate too much and had nothing to think about. Athletics don’t make anybody long-lived or useful.”

“Since the days of Descartes it has been a conception familiar to philosophers that every visible event in nature might be explained by previous visible events, and that all the motions, for instance, of the tongue in speech, or of the hand in painting, might have merely physical causes. If consciousness is thus accessory to life and not essential to it, the race of man might have existed upon the earth and acquired all the arts necessary for its subsistence without possessing a single sensation, idea, or emotion. Natural selection might have secured the survival of those automata which made useful reactions upon their environment. An instinct would have been developed, dangers would have been shunned without being feared, and injuries avenged without being felt.”

“There was a distinct class of these gentlemen tramps, young men no longer young, who wouldn't settle down, who disliked polite society and the genteel conventions, but hadn't enough intelligence or enough conceit to think themselves transcendentalists or poets, in the style of Thoreau or of Walt Whitman.”

“Scepticism is the chastity of the intellect, and it is shameful to surrender it too soon or to the first comer: there is nobility in preserving it coolly and proudly through long youth, until at last, in the ripeness of instinct and discretion, it can be safely exchanged for fidelity and happiness.”

“Men become superstitious, not because they have too much imagination, but because they are not aware that they have any.”