Form your life humanly, and you have done enough: but you will never reach the height of art and the depth of science without something divine.

The naive is what is or appears to be natural, individual, or classical to the point of irony or to the point of continuous alternation of self-creation and self-destruction. If it is only instinct, then it is childlike, childish, or silly; if it is only intention, it becomes affectation.

One has only as much morality as one has philosophy and poetry.

Mathematics is, as it were, a sensuous logic, and relates to philosophy as do the arts, music, and plastic art to poetry.

To disrespect the masses is moral; to honor them, lawful.

Imagination must first be filled to the point of saturation with life of every kind before the moment arrives when the friction of free sociability electrifies it to such an extent that the most gentle stimulus of friendly or hostile contact elicits from it lightning sparks, luminous flashes, or shattering blows.

A genuinely free and educated man should be able to tune himself, as one tunes a musical instrument, absolutely arbitrarily, at his convenience at any time and to any degree, philosophically or philologically, critically or poetically, historically or rhetorically, in ancient or modern form.