When I was young I pitied the old. Now old, it is the young I pity.

Kill one man and you're a murderer, kill a million and you're a conqueror.

Renown? I've already got more of it than those I respect, and will never have as much as those for whom I feel contempt.

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.

We spend our time envying people whom we wouldn't wish to be.

One must credit an hypothesis with all that has had to be discovered in order to demolish it.

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