The true method of discovery is like the flight of an aeroplane. It starts from the ground of particular observation; it makes a flight in the thin air of imaginative generalization; and it again lands for renewed observation rendered acute by rational interpretation.

Philosophy begins in wonder. And, at the end, when philosophic thought has done its best, the wonder remains.

Vigorous societies harbor a certain extravagance of objectives, so that men wander beyond the safe provision of personal gratifications.

The art of progress is to preserve order amid change and to preserve change amid order.

In all education the main cause of failure is staleness.

Each generation criticizes the unconscious assumptions made by its parent. It may assent to them, but it brings them out in the open.

Mathematics as a science, commenced when first someone, probably a Greek, proved propositions about "any" things or about "some" things, without specifications of definite particular things.