The most important tool of the theoretical physicist is his wastebasket.

If a man aspires towards a righteous life, his first act of abstinence is from injury to animals.

It is only men who are free, who create the inventions and intellectual works which to us moderns make life worth while.

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.

We sleep 1/3 of our lives away.

It may affront the military-minded person to suggest a regime that does not maintain any military secrets.

It is the same with people as it is with riding a bike. Only when moving can one comfortably maintain one's balance.