We have no words for speaking of wisdom to the stupid. He who understands the wise is wise already.

One of the greatest creations of the human mind is the art of reviewing books without having read them.

So-called professional mathematicians have, in their reliance on the relative incapacity of the rest of mankind, acquired for themselves a reputation for profundity very similar to the reputation for sanctity possessed by theologians.

The American who first discovered Columbus made a bad discovery.

A good method of discovery is to imagine certain members of a system removed and then see how what is left would behave: for example, where would we be if iron were absent from the world: this is an old example.

Most subjects at universities are taught for no other purpose than that they may be re-taught when the students become teachers.

He who says he hates every kind of flattery, and says it in earnest, certainly does not yet know every kind of flattery.