Never undertake anything for which you wouldn't have the courage to ask the blessings of heaven.

The great trick of regarding small departures from the truth as the truth itself - on which is founded the entire integral calculus - is also the basis of our witty speculations, where the whole thing would often collapse if we considered the departures with philosophical rigour.

One must judge men not by their opinions, but by what their opinions have made of them.

A man has virtues enough if he deserves pardon for his faults on account of them.

It not seldom happens that in the purposeless rovings and wanderings of the imagination we hunt down such game as can be put to use by our purposeful philosophy in its well-ordered household.

Man is always partial and is quite right to be. Even impartiality is partial.

If people should ever start to do only what is necessary millions would die of hunger.