I discuss the division of the soul in plato's "republic". i concentrate on the arguments and illustrative examples given in book iv, but i treat the descriptions of different types of person in viii-ix and elsewhere as further constituents of a single, coherent theory. on my interpretation plato distinguishes three basic kinds of motivation which he claims all human beings regularly experience in some degree. reason is itself the immediate source of certain desires. in addition, there are appetitive and also--quite distinct from either of the other two--competitive motivations.