In his Handbook, the Stoic philosopher Epictetus tells us that “the appropriate actions for us to do are usually measured out for us by our relations.”  Epictetus suggests that we can see how to act fittingly in any given situation, based on how we are related to the other people involved, whether as family members, friends, fellow citizens, enemies, or in whatever other way.

Roughly four centuries after Epictetus, the Platonic philosopher Simplicius takes Epictetus’ idea and runs with it.  In an extensive commentary on the Handbook, Simplicius uses this simple observation about appropriate actions as the invitation to give a detailed account of the various kinds of human relationships, followed by a beautiful encomium on the value and meaning of friendship.

Following Simplicius, we can consider four parts to the topic of friendship: (1) how to classify friendship among “relations” more generally; (2) the power of friendship to transform other types of relations; (3) criteria for the selection of friends; and (4) the important human goods that come from friendship.  And by using friendship as a special case of Epictetus’ general maxim, we can also step back to the bigger picture, to reflect on the ways in which other relations can guide our actions, whether those relationships are something we’re “stuck with” (like a brother who will always be my brother) or something we can choose to begin or end (like making an enemy, or making peace with a former enemy).