The prehistorical and primitive period represents the true infancy of the mind.

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

Feeling is the consciousness of the resulting conditions - of success, failure, equilibrium, compromise or balance, in this continuous rivalry of ideas.

In the first place, Descartes stands for the most explicit and uncompromising dualism between mind and matter.

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.

All along we find that social life - religion, politics, art - reflects the stages reached in the development of the knowledge of self; it shows the social uses made of this knowledge.

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