Adolescence is a new birth, for the higher and more completely human traits are now born.

All possible truth is practical. To ask whether our conception of chair or table corresponds to the real chair or table apart from the uses to which they may be put, is as utterly meaningless and vain as to inquire whether a musical tone is red or yellow. No other conceivable relation than this between ideas and things can exist. The unknowable is what I cannot react upon. The active part of our nature is not only an essential part of cognition itself, but it always has a voice in determining what shall be believed and what rejected.

The man of the future may, and even must, do things impossible in the past and acquire new motor variations not given by heredity.

Oneness with Nature is the glory of childhood; oneness with childhood is the glory of the Teacher.

Education has now become the chief problem of the world, its one holy cause. The nations that see this will survive, and those that fail to do so will slowly perish. . . . There must be re-education of the will and of the heart as well as of the intellect; and the ideals of service must supplant those of selfishness and greed.

This splendid subject [mathematics], queen of all exact sciences, and the ideal and norm of all careful thinking.

The years from about eight to twelve constitute a unique period of human life.