Men still have to be governed by deception.

Be attentive, feel nothing in vain, measure and compare: this is the whole law of philosophy.

I have remarked very clearly that I am often of one opinion when I am lying down and of another when I am standing up.

As I take up my pen I feel myself so full, so equal to my subject, and see my book so clearly before me in embryo, I would almost like to try to say it all in a single word.

Ask yourself always: how can this be done better?

There are people who possess not so much genius as a certain talent for perceiving the desires of the century, or even of the decade, before it has done so itself.

If another Messiah was born he could hardly do so much good as the printing-press.