In Nicomachean Ethics 8.13–8.14, Aristotle returns from a discussion of friendship in politics and the family to his broader theme of friendship and equality. Here, in the course of examining the reproaches and quarrels that arise in certain confused or deceptive forms of utilitarian friendship, he in fact offers his most profound reflections on the critical question of the relation of friendship to justice. Aristotle opens 8.13 with an explicit return to his threefold classification of friendships as based on utility, pleasure, and virtue. The sympathetic concern that grows out of kinship or similarity, which had come to appear as a fourth and crucial root of friendship, and which figured prominently in the previous chapters, now recedes again from the picture. Instead, Aristotle focuses attention on the difficulties of establishing and maintaining equality between friends, especially when their capacities differ greatly, reminding us of the unsolved questions of what motivates benefactors to act as they do, and how most unequal friendships can ever really be balanced to everyone's satisfaction.

Quarrels

“Complaints and reproaches arise solely or chiefly in friendships of utility, and with good reason,” Aristotle says (1162b5–6). But the reasons he goes on to give to explain why complaints and reproaches do not arise in friendships of virtue and pleasure in fact indicate just how unusual these friendships would have to be to be perfectly free of grievances: