If a given scientist had not made a given discovery, someone else would have done so a little later. Johann Mendel dies unknown after having discovered the laws of heredity: thirty-five years later, three men rediscover them. But the book that is not written will never be written. The premature death of a great scientist delays humanity; that of a great writer deprives it.

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.

To reflect is to disturb one's thoughts.

Science had better not free the minds of men too much, before it has tamed their instincts.

What scientist would not long to go on living, if only to see how the little truths he has brought to light will grow up?

Being right is less important to us than the freedom to be wrong.

I don't judge a regime by the damning criticism of the opposition, but by the ingenuous praise of the partisan.