In an effort to prove that no sinner loves himself, STA first notes that one sense of “myself” is simply as a living entity, and in this sense all persons love themselves so far as they eat, sleep, drink, etc. He then describes the self of preeminence, which is a self one can discover in the way that armies are named by their generals. To say that Lee advanced on Hooker at the battle of Chancellorsville or that Patton advanced on Berlin is to see the self as what commands in concert with its subordinates. In this second sense, the human person is a self so far as one part of him rules the drives which can either dominate reason or be trained into supporting it and giving it force.
In this second sense one is only a self when he is not divided or at odds with himself, since a self is one thing and divided things aren’t. Any opposition between emotional drives and rational awareness of the good eliminates the self in this second sense, and therefore leaves literally no self at all for the sinner to love. The students joked that to take self in this way means there is no one in Hell and everyone is a saint. There’s something to this, though it might be better to appreciate how “selfless action”, “selfless love” and “love of self” have entirely different senses for the sinner and the saint.