The truth is often a terrible weapon of aggression. It is possible to lie, and even to murder, with the truth.

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.

What is courage? Courage is the willingness to risk failure...There is only one danger I find in life, and that, indeed, is a real one. You may take too many precautions.

There is a courage of happiness as well as a courage of sorrow.

The mathematical life of a mathematician is short. Work rarely improves after the age of twenty-five or thirty. If little has been accomplished by then, little will ever be accomplished.

You can be healed of depression if every day you begin the first thing in the morning to consider how you will bring a real joy to someone else.

Everything can always be different!