"On fact, the whole machinery of our intelligence, our general ideas and laws, fixed and external objects, principles, persons, and gods, are so many symbolic, algebraic expressions. They stand for experience; experience which we are incapable of retaining and surveying in its multitudinous immediacy. We should flounder hopelessly, like the animals, did we not keep ourselves afloat and direct our course by these intellectual devices. Theory helps us to bear our ignorance of fact."

“Eternal vigilance is the price of knowledge.”

“American life is a powerful solvent. As it stamps the immigrant, almost before he can speak English, with an unmistakable muscular tension, cheery self-confidence and habitual challenge in the voice and eyes, so it seems to neutralize every intellectual element, however tough and alien it may be, and to fuse it in the native good-will, complacency, thoughtlessness, and optimism.”

“The soul, too, has her virginity and must bleed a little before bearing fruit.”

“It is not society's fault that most men seem to miss their vocation. Most men have no vocation.”

“Skepticism, like chastity, should not be relinquished too readily.”

“Perhaps the only true dignity of man is his capacity to despise himself.”