Whoever is careless with the truth in small matters cannot be trusted in important affairs.

For science can only ascertain what is, but not what should be, and outside of its domain value judgments of all kinds remain necessary. Religion, on the other hand, deals only with evaluations of human thought and action: it cannot justifiably speak of facts and relationships between facts.

Everyone has two choices. We're either full of love... or full of fear.

You teach me baseball and I'll teach you relativity...No we must not. You will learn about relativity faster than I learn baseball.

As long as there are sovereign nations possessing great power, war is inevitable.

It is a very high goal which, with our weak powers, we can reach only very inadequately, but which gives a sure foundation to our aspirations and valuations.

Classical thermodynamics ... is the only physical theory of universal content which I am convinced ... will never be overthrown.