Which parts of Socrates's argument depend on a notion of the "usefulness" of a person? How do they relate?
The notion of usefulness serves as the anchor for a number of Socrates's arguments in the Lysis, including Socrates's first conversation with Lysis. Socrates is attempting to put Lysis in a humbler position, one in which he will be eager to have a true teacher (and perhaps a lover). Since Lysis is just a boy, the standard elenchus, in which the pompous ideals of the interlocutor are dismantled, will not work so well; Lysis doesn't claim to have a theory of friendship, and he is unlikely to be excited by appeals to abstract virtue. Therefore, Socrates engages him on the level of use-value and power: Lysis is forbidden to drive chariots now, but he might do this and much more (rule Athens, assist the King of Persia) if only he were of use. The way to become useful, Socrates argues, is through knowledge and understanding. Whatever Lysis wants to do, people will let him do it if he understands it. With this argument, Socrates uses practical use (chariot driving, cooking, medicine) to convince Lysis of the ideal of knowledge.
Use also defines one aspect of Socrates's discussion of friendship. Namely, usefulness is requisite to desire, which is requisite to friendship. Thus, likeness cannot be the condition for friendship, since like will not be "of any use" to like (since they share the same properties). Thus, the idea of usefulness underpins both friendship and desire at certain strategic points. In the abstract, usefulness is necessary for ideal friendship. On the more practical level, the desire to be useful (and thereby to have power over certain things) is the tool with which Socrates woos Lysis toward seeking a teacher. Socrates, then, both argues for the importance of usefulness and demonstrates this importance in his interactions with Lysis.
For each of the following possible causes of friendship, explain why it is rejected: likeness, unlikeness, and goodness.
Likeness is rejected as the primary cause of friendship because the extent to which two people are identical is precisely the extent to which they can give each other nothing they don't already have. Thus, two people are useless to each other in as much as they are alike, and so can have no need of each other (they cannot desire each other). Goodness is rejected for much the same reason: that which is already good cannot need anything else to make it good, and so the good does not need a friend. Unlikeness is rejected simply because the friendships it suggests are "monstrous." The good would be the friend of the evil, the just of the unjust, and so on. It is judged to be intuitively wrong.
Discuss some moments in the dialogue at which intoxication, confusion, or poetic inspiration take over for rational dialogue. How do these moments function in the structure of the dialogue as a whole?
The Lysis contains a number of remarkable points at which the plot, or dialogue, seems to turn on emotional factors rather than on analytic ones. This is certainly true at the beginning of the text, when Socrates seems drawn into the situation because of the intrigue surrounding Hippothales and Lysis (not to mention Lysis's famed beauty). Here, blushes, embarrassment, and advice in matters of love have the upper hand. But even in the course of the dialogue proper, the very content of the argument is sometimes due to factors outside the realm of philosophy per se. Perhaps the most notable of these moments are the two that introduce and dismiss Socrates argument that the neutral loves the good because of the presence of evil. When he first introduces this idea, Menexenus asks him what he means; Socrates replies, "the truth is that I don't know, but my head is dizzy with thinking of the argument ." He then proceeds through a few poetic reflections on beauty, which appear to be more or less unrelated to the thesis at hand. That thesis (about the neutral, good, and evil) is rejected in a similar way, with Socrates simply succumbing to an "unaccountable suspicion" that it is false before he has any concrete arguments against it. The two hypotheses about likeness (that "the like is the friend" and that "the unlike is the friend") also have origins in something other than strict analysis: both are introduced through poetry.
There are also at least two points at which Socrates interrupts himself and starts over. These moments are interesting partly for their implication that Socrates is confused (or that he is worried about talking over the heads of his young audience), but more so for the questions they raise about Plato's use of rhetoric in portraying Socrates's speech. In other words, Socrates may sound confused, but the real question is why Plato would make him sound confused. There are many possible explanations for this: Plato may wish to show that Socrates is really engaging in a real-time thinking process, he may want to show Socrates struggling to be understood by the boys, etc. In short, both these moments of hesitation and the moments of dizziness or poetry, besides lending the dialogue a destabilizing element, also serve to fill out Plato's sketch of Socrates as a character. This is not pure philosophy, after all, but philosophy in a spoken form.