 A final question, shared by many writers, is whether “obligation” is the only concept that we need here. No doubt, it’s useful. But there is a vast and variegated range of things that we do with other people that we also turn inwards in an intriguing way. Consider the virtues of patience, forgiveness, compassion, kindness, and appreciation. It is not so obvious that the right theory of “obligations” is going to tell us how these things work in general, much less in the solo case.