Only morality in our actions can give beauty and dignity to life.

The most important question a person can ask is, "Is the Universe a friendly place?

Physical concepts are free creations of the human mind, and are not, however it may seem, uniquely determined by the external world.

As an elderly man, I have remained estranged from the society here.

Nothing that I can do or say will change the structure of the universe. But maybe, by raising my voice, I can help the greatest of all causes — good will among men and peace on earth.

One must shy away from questionable undertakings, even when they bear a high-sounding name.

You think you have troubles with mathematics . . . I assure you mine are still bigger.