This episode is a discussion of the concluding paragraphs of Republic, Book IV. It is about the question "Why do we need a theory to explain self-control?" Socrates would answer this by saying "Because we need to show how one and the same person can control his or her appetites or emotions." Socrates introduces the theory of a tripartite soul. We can control ourselves only if there is one part of the soul that does the controlling and the other parts that are controlled. But this account leads to the Humunculus Problem (if there are parts of the soul, then the parts must be directed to what they do by their own parts, and so on ad infinitum. This episode shows why a tripartite theory is unnecessary. The remainder of this episode discusses Socrates' theory of how justice and all the other virtues of the soul are tied either to tasks of the parts of the soul or to the "best relationships" between the parts of the soul.