Everything in science depends on what one calls an aperçu, on becoming aware of what is at the bottom of the phenomena. Such becoming aware is infinitely fertile.

Even though the world as a whole progresses, youth must always start again from the beginning, and as individuals go through the epochs of the world's culture.

There are but few who have ideas and are, at the same time, capable of action. Ideas enlarge but stymie, action enlivens but confines.

He who is wise puts aside all claims which may dissipate his attention, and confining himself to one branch excels in that.

Hypotheses are only the pieces of scaffolding which are erected round a building during the course of construction, and which are taken away as soon as the edifice is completed.

Know thyself? If I knew myself I would run away.

Mathematics can remove no prejudices and soften no obduracy. It has no influence in sweetening the bitter strife of parties, and in the moral world generally its action is perfectly null.