Philosophy begins in wonder. And, at the end, when philosophic thought has done its best, the wonder remains.

It is the business of future to be dangerous.... The major advances in civilization are processes that all but wreck the societies in which they occur.

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.

No reason can be given for the nature of God, because that nature is the ground of rationality.

The way in which the persecution of Galileo has been remembered is a tribute to the quiet commencement of the most intimate change in outlook which the human race had yet encountered. Since a babe was born in a manger, it may be doubted whether so great a thing has happened with so little stir

You cannot be wise without some basis of knowledge, but you may easily acquire knowledge and remain bare of wisdom.

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.