The great poem and the deep theorem are new to every reader, and yet are his own experiences, because he himself recreates them.

The child is not a prisoner of its inheritance; it holds its inheritance as a new creation which its future actions will unfold.

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.

Whether our work is art or science or the daily work of society, it is only the form in which we explore our experience which is different.

One original thought is worth the sum total of human knowledge, because it advances the sum total of human knowledge by that one original thought.

The progress of science is the discovery at each step of a new order which gives unity to what had seemed unlike.

Dissent is the mark of freedom, as originality is the mark of independence of mind. … No one can be a scientist … if he does not have independence of observation and of thought.