The close and thoughtful observer more and more learns to recognize his limitations. He realizes that with the steady growth of knowledge more and more new problems keep on emerging.

What is uttered from the heart alone, Will win the hearts of others to your own.

Love is an ideal thing, marriage a real thing; a confusion of the real with the ideal never goes unpunished.

I have heard myself accused of being an opponent, an enemy of mathematics, which no one can value more highly than I, for it accomplishes the very thing whose achievement has been denied me.

How to please the public - that's the test, But nowadays I find I'm in a fix; I know they're not accustomed to the best, But they've all read so much they know the tricks. How can we give then something fresh and new That's serious, but entertaining too?

A useless life is an early death.

Life is not anything, but an opportunity for something.