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

My pessimism extends to the point of even suspecting the sincerity of other pessimists.

The ideal, without doubt, varies, but its enemies, alas, are always the same.

It is sometimes important for science to know how to forget the things she is surest of.

We give others praise which we ourselves don't believe, as long as they respond with praise we can believe.

Kill one man, and you are a murderer. Kill millions of men, and you are a conqueror. Kill them all, and you are a god.

Theories pass. The frog remains.