Never let yourself be seduced by any problem, no matter how difficult.

Lasting harmony with a woman (was) an undertaking in which I twice failed rather disgracefully.

War cannot be humanized. It can only be abolished.

I believe, indeed, that overemphasis on the purely intellectual attitude, often directed solely to the practical and factual, in our education, has led directly to the impairment of ethical values. I am not thinking so much of the dangers with which technical progress has directly confronted mankind, as of the stifling of mutual human considerations by a 'matter-of-fact' habit of thought which has come to lie like a killing frost upon human relations. Without 'ethical culture' there is no salvation for humanity.

One lives one's life under constant tension, until it's time to go for good

Certainly there are things worth believing. I believe in the brotherhood of man and the uniqueness of the individual. But if you ask me to prove what I believe, I can't. You know them to be true but you could spend a whole lifetime without being able to prove them. The mind can proceed only so far upon what it knows and can prove. There comes a point where the mind takes a leap—call it intuition or what you will—and comes out upon a higher plane of knowledge, but can never prove how it got there. All great discoveries have involved such a leap.

What is this frog and mouse battle among the mathematicians?