We have three approaches at our disposal: the observation of nature, reflection, and experimentation. Observation serves to assemble the data, reflection to synthesise them and experimentation to test the results of the synthesis. The observation of nature must be assiduous, just as reflection must be profound, and experimentation accurate. These three approaches are rarely found together, which explains why creative geniuses are so rare.

A narrow and moralistic view of morals is responsible for the failure to recognize that all the aims and values which are desirable in education are themselves moral. Discipline, natural development, culture, social efficiency, are moral traits - marks of a person who is a worthy member of that society which it is the business of education to further.

The only way to abolish war is to make peace seem heroic.

The struggle for democracy has to be maintained on as many fronts as culture has aspects: political, economic, international, educational, scientific and artistic, religious.

Liberty is not just an idea, an abstract principle. It is power, effective power to do specific things. There is no such thing as liberty in general; liberty, so to speak, at large.

The most important factor in the training of good mental habits consists in acquiring the attitude of suspended conclusion, and in mastering the various methods of searching for new materials to corroborate or to refute the first suggestions that occur.

Nature as a whole is a progressive realization of purpose strictly comparable to the realization of purpose in any single plant or animal.