Heredity provides for the modification of its own machinery.

Pythagoras took the next important step by subordinating the mere matter of nature to its essential principle of form and order, identifying the latter with reason or the soul.

Like all science, psychology is knowledge; and like science again, it is knowledge of a definite thing, the mind.

The fact that tradition hinders the individual savage from thinking logically by no means proves that he cannot think logically.

In Socrates' thought the two marks of individual self-consciousness appear; it is practical and it is social.

The development of the meaning attaching to the personal self, the conscious being, is the subject matter of the history of psychology.

Psychology more than any other science has had its pseudo-scientific no less than its scientific period.