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

The dualism itself becomes a sort of presupposition or datum; its terms condition the further problem.

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

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

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.

In conclusion we may say, in view of the confirmation that our study has given of the parallelism between individual and racial thought of the Self, that in the history of psychology we discern the great profile which the race has drawn on the pages of time.