I argue that Republic presents thumos as a limited, or flawed, principle of psychic unity. My central claim is that Plato both makes this assertion about the necessary limitations of thumos, and can defend it, because he understands thumos as the pursuit of to oikeion, or one’s own. So understood, the thumoetic part divides the world into self and other and pursues the defense of the former from the latter. As a result, when confronted with a conflicting desire, the thumoetic (...) part makes sense of that desire as an irredeemable opponent. That, in turn, precludes the persuasion of desires that Plato sees as necessary for psychic harmony. (shrink)