The paradox is now fully established that the utmost abstractions are the true weapons with which to control our thought of concrete fact.

Nature is probably quite indifferent to the aesthetic preferences of mathematicians.

I would be a billionaire if I was looking to be a selfish boss. That's not me.

Through and through the world is infested with quantity: To talk sense is to talk quantities. It is no use saying the nation is large. . . . How large? It is no use saying the radium is scarce. . . . How scarce? You cannot evade quantity. You may fly to poetry and music, and quantity and number will face you in your rhythms and your octaves.

A great society is a society in which its men of business think greatly of their functions.

In modern times the belief that the ultimate explanation of all things was to be found in Newtonian mechanics was an adumbration of the truth that all science, as it grows towards perfection, becomes mathematical in its ideas.

I always feel that I have two duties to perform with a parting guest: one, to see that he doesn't forget anything that is his; the other, to see that he doesn't take anything that is mine.