The greatest human quest is to know what one must do in order to become a human being.
The instruction of children should aim gradually to combine knowing and doing. Among all sciences mathematics seems to be the only one of a kind to satisfy this aim most completely.
A lie is the abandonment and, as it were, the annihilation of the dignity by man.
Only the descent into the hell of self-knowledge can pave the way to godliness.
All perception is colored by emotion.
Even a man's exact imitation of the song of the nightingale displeases us when we discover that it is a mimicry, and not the nightingale.