To be able to concentrate for a considerable time is essential to difficult achievement.

Patriots always talk of dying for their country and never of killing for their country.

The whole problem with the world is that fools and fanatics are always so certain of themselves, and wiser people so full of doubts.

To teach how to live with uncertainty, and yet without being paralyzed by hesitation, is perhaps the chief thing that philosophy in our age can still do for those who study it.

Many a man will have the courage to die gallantly, but will not have the courage to say, or even to think, that the cause for which he is asked to die is an unworthy one.