Beyond all our actions stands the larger shadow: How are we to choose between what we have been taught to think right and something else which manifestly succeeds?

There is no absolute knowledge. And those who claim it, whether they are scientists or dogmatists, open the door to tragedy.

Satire is not a social dynamite. But it is a social indicator: it shows that new men are knocking at the door.

Man masters nature not by force, but by understanding

Einstein was a man who could ask immensely simple questions. And what his work showed is that when the answers are simple too, then you can hear God thinking.

The Principle of Tolerance, fixed once for all the realization that all knowledge is limited. It is an irony of history that at the very time when this was being worked out, there should rise, under Hitler in Germany and other tyrants elsewhere, a counter-conception: a principle of monstrous certainty. When the future looks back on the 1930's, it will think of them as a crucial confrontation of culture as I have been expounding it - the ascent of man against the throwback to the despots' belief that they have absolute certainty.

The richness of human life is that we have many lives, we live the events that do not happen (and some that cannot) as vividly as those that do, and if thereby we die a thousand deaths, that is the price we pay...