Inventive genius requires pleasurable mental activity as a condition for its vigorous exercise. "Necessity is the mother of invention" is a silly proverb. "Necessity is the mother of futile dodges" is much closer to the truth. The basis of growth of modern invention is science, and science is almost wholly the outgrowth of pleasurable intellectual curiosity.

I am sure that one secret of a successful teacher is that he has formulated quite clearly in his mind what the pupil has got to know in precise fashion. He will then cease from half-hearted attempts to worry his pupils with memorizing a lot of irrelevant stuff of inferior importance.

After you understand about the sun and the stars and the rotation of the earth, you may still miss the radiance of the sunset.

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

Everything of importance has been said before by somebody who did not discover it.

Religion is what a person does in his solitariness.

All practical teachers know that education is a patient process of mastery of details, minute by minute, hour by hour, day by day.