Youth is life as yet unblemished by much tragedy, but hardly by TV.

A man really writes for an audience of about ten persons. Of course if others like it, that is clear gain. But if those ten are satisfied, he is content.

In modern times the belief that the ultimate explanation of all things was to be found in Newtonian mechanics was an adumbration of the truth that all science, as it grows towards perfection, becomes mathematical in its ideas.

Religion will not regain its old power until it can face change in the same spirit as does science.

Education which is not modern share the fate of all organic things which are kept too long.

In a sense, knowledge shrinks as wisdom grows, for details are swallowed up in principles. The details for knowledge which are important, will be picked up ad hoc in each avocation of life, but the habit of the active utilization of well-understood principles is the final possession of WISDOM.

Fundamental progress has to do with the reinterpretation of basic ideas.