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

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

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.

Plato stands for the union of truth and goodness in the supreme idea of God.

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

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