H. P. Grice, "The aporia of 'amicus' as 'alter ego'"

ALTER EGO -- friendship Ethics A prominent moral topic in Greek ethics from Socrates to the Stoics. The word is generally used to translate the Greek word philia, although the latter covers a broader area, including all personal relationships motivated by mutual love and the relationships amongst family members. Aristotle’s Nicomachean Ethics deals with the problem of friendship in detail. He divides friendship into three types: that based on mutual pleasure, that based on utility, and that based on the mutual appreciation of virtuous character. The last type is the real and genuine kind of friendship. Only a virtuous person can be a friend to another virtuous person, and a friend in this relationship is another self, a mirror of one’s character. Aristotle characterizes friendship as involving the pursuit of the goods of one’s friends for their own sake, and involving reciprocity of sentiment. The issue of friendship has fallen into neglect in modern ethics, for it believes that friendship is a private affair, a matter of personal choice, rather than a part of common morality. The topic has been revived with the emergence of contemporary virtue ethics, and especially of feminist ethics, both of which emphasize personal relationships rather than universalistic moral considerations. “Friendship is said to be reciprocated goodwill.” Aristotle, Nicomachean Ethics