Lysis does not involve any sustained inquiry into the nature of the good (as some of the other dialogues do), but good is suggested as an obvious choice for the quality that motivates friendship. Perhaps, proposes Socrates, the friend is simply the good. It has already been concluded at this point, in the discussion of like befriending like, that evil can be the friend of nobody; since evil is not even like itself (not in harmony with itself), it cannot be like (or in harmony with) anything else. Socrates also seems to take it as a given that evil can never be a friend.

The problem with the proposition that the good is the friend is similar to the problem with like befriending like: what is already good has no need of more good, and so its desire for a friend cannot be caused by the desire to improve. Socrates's solution to this problem is ingenious, if a bit awkward. The good cannot be the friend of the good or of the evil, but it could be the friend of that which is neither good nor evil (i.e., the neutral). The solution, then, would be that friendship is caused by the neutral desiring the good because of the presence of evil. Socrates is pleased with this formulation, but it is soon dropped due to an entirely new objection. On this model, it would seem that the neutral loves the good "for the sake of" evil, a situation that would make the cause of friendship contingent on a secondary goal (that of escaping evil). This is not a strong enough cause for Socrates, who wants an ultimate and self-sufficient cause. Thus, he argues that, even if evil completely disappeared, desire, which is itself neither good nor evil, would remain. This means that love and friendship would probably occur regardless of the presence of evil. Lysis never addresses the lingering question in this area: namely, why can't the neutral be said to love the good regardless of evil?