It is impossible to get out of a problem by using the same kind of thinking that it took to get into it.

I believe that a simple and unassuming manner of life is best for everyone, best both for the body and the mind.

Even if only 2 percent of those assigned to perform military service should announce their refusal to fight, governments would be powerless, they would not dare send such a large number of people to jail.

Not until we dare to regard ourselves as a nation, not until we respect ourselves, can we gain the esteem of others, or rather only then will it come of its own accord

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

When I think of the most able students I have encountered in my teaching - I mean those who have distinguished themselves not only by skill but by independence of thought - then I must confess that all have had a lively interest in epistemology.

When the Special Theory of Relativity began to germinate in me, I was visited by all sorts of nervous conflicts... I used to go away for weeks in a state of confusion.