Kill one man, and you are murderer.

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.

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

We are not naïve enough to ask for pure men; we ask merely for men whose impurity does not conflict with the obligations of their job.

Science has made us gods even before we are worthy of being men.

To love an idea is to love it a little more than one should.

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