The basis for poetry and scientific discovery is the ability to comprehend the unlike in the like and the like in the unlike.

The central opposition between magic and science is the opposition between power and knowledge.

The paradox of knowledge is not confined to the small, atomic scale; on the contrary, it is as cogent on the scale of man, and even of the stars.

Knowledge is an unending adventure at the edge of uncertainty.

Many theories of the ancient world seem terribly childish today, a hodge-podge of fables and false comparisons.But our theories will seem childish five-hundred years from now.Every theory is based on some analogy, and sooner or later the theory fails because the analogy turns out to be false. A theory in its day helps to solve the problems of the day.

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.

Knowledge is not a loose leaf notebook of facts.