If the human race wishes to have a prolonged and indefinite period of material prosperity, they have only got to behave in a peaceful and helpful way toward one another.

If the past sits in judgment on the present, the future will be lost.

I did not like the man [Niels Bohr] when you showed him to me, with his hair all overhis head.

You see these dictators up on their pedestals, surrounded by the bayonets of their soldiers and the truncheons of their police. They're afraid of words and thought. ... They make frantic efforts to bar our thoughts and words. ... A state of society where men may not speak their mind - where children denounce their parents to the police - where a businessman or small shopkeeper ruins his competitor by telling tales about his private opinion. Such a state of society cannot long endure if it is continually in contact with the healthy outside world.

If you recognize anyone it does not mean you like them.

Praise the humanities, my boy. That'll make them think you're broadminded!

One man with conviction will overwhelm a hundred who have only opinions.