What do you first do when you learn to swim? You make mistakes, do you not? And what happens? You make other mistakes, and when you have made all the mistakes you possibly can without drowning - and some of them many times over - what do you find? That you can swim? Well - life is just the same as learning to swim! Do not be afraid of making mistakes, for there is no other way of learning how to live!

Far more unwaveringly, the neurotic keeps before his eye his God, his idol, his ideal of personality and clings to his guiding principle, losing sight in the meanwhile of reality, whereas the normal person is always ready to dispense with this crutch, this aid, and reckon unhampered with reality.

In the company of friends, writers can discuss their books, economists the state of the economy, lawyers their latest cases, and businessmen their latest acquisitions, but mathematicians cannot discuss their mathematics at all. And the more profound their work, the less understandable it is.

Meanings are not determined by situations, but we determine ourselves by the meanings we give to situations.

We must interpret a bad temper as a sign of inferiority.

Follow your heart always, and remember to take your head along with you.

Mathematics is pure language - the language of science. It is unique among languages in its ability to provide precise expression for every thought or concept that can be formulated in its terms.