The real difference between a man's scientific judgments about himself and the judgment of others about him is he has added sources of knowledge.

It will of course, be understood that directly or indirectly, soon or late, every advance in the sciences of human nature will contribute to our success in controlling human nature and changing it to the advantage of the common wheel.

Human beings are accustomed to think of intellect as the power of having and controlling ideas and of ability to learn as synonymous with ability to have ideas. But learning by having ideas is really one of the rare and isolated events in nature.

Psychology helps to measure the probability that an aim is attainable.

The intellectual evolution of the race consists in an increase in the number, delicacy, complexity, permanence and speed of formation of such associations.

Human education is concerned with certain changes in the intellects, characters and behavior of men, its problems being roughly included under these four topics: Aims, materials, means and methods.

Just as the science and art of agriculture depend upon chemistry and botany, so the art of education depends upon physiology and psychology.