The intelligent man finds almost everything ridiculous, the sensible man hardly anything.

We gladly put antiquity above our age but not posterity. Only a father doesn't begrudge his son's talent.

There is nothing more frightful than for a teacher to know only what his scholars are intended to know.

At all times it has not been the age, but individuals alone, who have worked for knowledge. It was the age which put Socrates to death by poison, the age which burnt Huss. The ages have always remained alike.

What a torment it is to see so much loveliness passing and repassing before us, and yet not dare to lay hold of it!

Mankind? That is an abstraction. There have always been and always will be only individuals.

A mathematician is only perfect insofar as he is a perfect man, sensitive to the beauty of truth.