Concepts which have proved useful for ordering things easily assume so great an authority over us, that we forget their terrestrial origin and accept them as unalterable facts. They then become labeled as 'conceptual necessities,' etc. The road of scientific progress is frequently blocked for long periods by such errors.

When a man points a finger at someone else, he should remember that three of his fingers are pointing at himself. Do not worry about your difficulties in mathematics; I can assure you that mine are still greater.

There is, however, one other human right which is infrequently mentioned but which seems to be destined to become very important: this is the right, or the duty, of the individual to abstain from cooperating in activities which he considers wrong or pernicious.

One has to realize that the powerful industrial groups concerned in the manufacture of arms are doing their best in all countries to prevent the peaceful settlement of international disputes, and that rulers can achieve this great end only if they are sure of the vigorous support of the majority of their peoples.

Since the mathematicians have invaded the theory of relativity I do not understand it myself any more.

Life isn't worth living, unless it is lived for someone else.

I believe that we don't need to worry about what happens after this life, as long as we do our duty here-to love and to serve.