What makes our opponents useful is that they allow us to believe that without them we would be able to realize our goals.

There are things that don't deserve to be said briefly.

Never feel remorse for what you have thought about your wife; she has thought much worse things about you.

Falsity cannot keep an idea from being beautiful; there are certain errors of such ingenuity that one could regret their not ranking among the achievements of the human mind.

The nobility of a human being is strictly independent of that of his convictions.

It is not easy to imagine how little interested a scientist usually is in the work of any other, with the possible exception of the teacher who backs him or the student who honors him.

A married couple are well suited when both partners usually feel the need for a quarrel at the same time.