Very few men can be genuinely happy in a life involving continual self-assertion against the skepticism of the mass of mankind, unless they can shut themselves up in a coterie and forget the cold outer world. The man of science has no need of a coterie, since he is thought well of by everybody except his colleagues. The artist, on the contrary, is in the painful situation of having to choose between being despised and being despicable.

With equal passion I have sought knowledge. I have wished to understand the hearts of men. I have wished to know why the stars shine. And I have tried to apprehend the Pythagorean power by which number holds sway about the flux. A little of this, but not much, I have achieved.

The infliction of cruelty with a good conscience is a delight to moralists - that is why they invented hell.

If you question any candid person who is no longer young, he is very likely to tell you that, having tasted life in this world, he has no wish to begin again as a "new boy" in another.

I believe myself that romantic love is the source of the most intense delights that life has to offer. In the relation of a man and woman who love each other with passion and imagination and tenderness, there is something of inestimable value, to be ignorant of which is a great misfortune to any human being.

Science is what you know, philosophy is what you don't know.

I think it would be just to say the most essential characteristic of mind is memory, using this word in its broadest sense to include every influence of past experience on present reactions.