Nothing reveals a man's character better than the kind of joke at which he takes offense.

Honest unaffected distrust of human abilities under all circumstances is the surest sign of strength of mind.

The highest level than can be reached by a mediocre but experienced mind is a talent for uncovering the weaknesses of those greater than itself.

A book which, above all others in the world, should be forbidden, is a catalogue of forbidden books.

He was then in his fifty-fourth year, when even in the case of poets reason and passion begin to discuss a peace treaty and usually conclude it not very long afterwards.

I have often noticed that when people come to understand a mathematical proposition in some other way than that of the ordinary demonstration, they promptly say, "Oh, I see. That's how it must be." This is a sign that they explain it to themselves from within their own system.

We accumulate our opinions at an age when our understanding is at its weakest.