All experience is an arch, to build upon.

[P]olitical and social and scientific values ... should be correlated in some relation of movement that could be expressed in mathematics, nor did one care in the least that all the world said it could not be done, or that one knew not enough mathematics even to figure a formula beyond the schoolboy s=(1/2)gt2. If Kepler and Newton could take liberties with the sun and moon, an obscure person ... could take liberties with Congress, and venture to multiply its attraction into the square of its time. He had only to find a value, even infinitesimal, for its attraction.

It [love] is a disease to be born with patience, like any nervous complaint, and to be treated with counter-irritants.

You say that love is nonsense. I tell you it is no such thing. For weeks and months it is a steady physical pain, an ache about the heart, never leaving one, by night or by day; a long strain on one's nerves like toothache or rheumatism, not intolerable at any one instant, but exhausting by its steady drain on the strength.

Of all studies, the one he would rather have avoided was that of his own mind. He knew no tragedy so heartrending as introspection.

Simplicity is the most deceitful mistress that ever betrayed man.

Morality is a private and costly luxury.