The guiding motto in the life of every natural philosopher should be, seek simplicity and distrust it.

There is a tradition of opposition between adherents of induction and of deduction. In my view it would be just as sensible for the two ends of a worm to quarrel.

The race that does not value trained intelligence is doomed.

"One and one make two" assumes that the changes in the shift of circumstance are unimportant. But it is impossible for us to analyze this notion of unimportant change.

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.

An enormous part of our mature experience cannot not be expressed in words.

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