Psyche and Reason

Plato precedes Aristotle in conceiving Reason as the internal organizing principle of the Psyche.  But, while for his successor the concept is instantiated in only a personal Psyche, for Plato, a Polis, as well as its citizens individually, possesses a Psyche.  Now, Kant's innovation is to bridge the two concepts--to conceive oneself as a member of a Rational whole.  However, absent an understanding of that original intra-Psychic structure, and of Plato's dual application of it, Reason can be, and often is, e. g. in Freud's model of the Psyche, posited as confronting the Ego as a hostile alien force, i. e. as part of the Superego.