Jowett: individual soul

But a further question arises : Is passion different from reason also, or only a kind of reason ; in which latter case, instead of three principles in the soul, there will only be two, the rational and the concupiscent ; or rather, as the State was composed of three classes, traders, auxiliaries, counsellors, so may there not be in the individual soul a third element which is passion or spirit, and when not corrupted by bad education is the natural auxiliary of reason ? THE REPUBLIC   BOOK IV

Such is the good and true City or State, and the good and true man is of the same pattern ; and if this is right every other is wrong ; and the evil is one which affects not only the ordering of the State, but also the regulation of the individual soul, and is exhibited in four forms. THE REPUBLIC BOOK V

The second proof is derived from the nature of the soul : seeing that the individual soul, like the State, has been divided by us into three principles, the division may, I think, furnish a new demonstration. THE REPUBLIC BOOK IX