But when all is said, the greatest art is to limit and isolate oneself.

A man may twist as he pleases, and do what he pleases, but he inevitably comes back to the track to which nature has destined him.

The Evil One has left, the evil ones remain.

Mathematicians are like Frenchmen: whatever you say to them they translate into their own language and forthwith it is something entirely different.

All professional men are handicapped by not being allowed to ignore things which are useless.

Divide and rule, a sound motto. Unite and lead, a better one.

If one has not read the newspapers for some months and then reads them all together, one sees, as one never saw before, how much time is wasted with this kind of literature.