A powerful idea communicates some of its strength to him who challenges it.

As long as men are free to ask what they must, free to say what they think, free to think what they will, freedom can never be lost and science can never regress.

Let us be grateful to people who make us happy, they are the charming gardeners who make our souls blossom.

Everything great in the world comes from neurotics. They alone have founded our religions and composed our masterpieces.

Happiness is beneficial for the body, but it is grief that develops the powers of the mind.