To come very near to a true theory, and to grasp its precise application, are two different things, as the history of science teaches us. Everything of importance has been said before by someone who did not discover it.

The aim of science is to seek the simplest explanation of complex facts. We are apt to fall into the error of thinking that the facts are simple because simplicity is the goal of our quest. The guiding motto in the life of every natural philosopher should be ``Seek simplicity and distrust it.''

Inventive genius requires pleasurable mental activity as a condition for its vigorous exercise

The safest general characterization of the European philosophical tradition is that it consists of a series of footnotes to Plato.

The ultimate metaphysical ground is the creative advance into novelty.

But you can catch yourself entertaining habitually certain ideas and setting others aside; and that, I think, is where our personal destinies are largely decided.

No Roman ever died in contemplation over a geometrical diagram.