Neither art thou the man to catch the fiend and hold him! [Ger., Du bist noch nicht der Mann den Teufel festzuhalten.

What in us the women leave uncultivated, children cultivate when we retain them near us.

Whether one show one's self a man of genius in science or compose a song, the only point is, whether the thought, the discovery, the deed, is living and can live on.

The field of experience is the whole universe in all directions. Theory remains shut up within the limits of human faculties.

All beginnings are delightful; the threshold is the place to pause.

Still this planet's soil for noble deeds grants scope abounding.

Die Mathematiker sind eine Art Franzosen. Spricht man zu ihnen, so übersetzen sie alles in ihre eigene Sprache, und so wird es alsobald etwas ganz anderes. Mathematicians are a kind of Frenchmen. Whenever you say anything or talk to them, they translate it into their own language, and right away it is something completely different.