To make astute people believe one is what one is not is, in most cases, harder than actually to become what one wishes to appear.

Cautiousness in judgment is nowadays to be recommended to each and every one: if we gained only one incontestable truth every ten years from each of our philosophical writers the harvest we reaped would be sufficient.

The most perfect ape cannot draw an ape; only man can do that; but, likewise, only man regards the ability to do this as a sign of superiority.

When a book and a head collide and a hollow sound is heard, must it always have come from the book?

There is no more important rule of conduct in the world than this: attach yourself as much as you can to people who are abler than you and yet not so very different that you cannot understand them.

Everyone is a genius at least once a year. The real geniuses simply have their bright ideas closer together.

There are people who think that everything one does with a serious face is sensible.