 Philosophers have often treated equality of some kind as a prerequisite of friendship (see  SEP entry on friendship).  In the Nicomachean Ethics, Aristotle distinguished among three kinds of friendship: friendships of pleasure, of utility, and of virtue. The last, the highest or truest form, required similarity of character. Philosophers since Aristotle have rejected some of his prerequisites for friendship, such as equality of social or economic status, but they have shared his view that friendship must be a relationship among equals. The debate has largely focused on the kind of equality that is required. Thus, Aristotle denied that parents and their children could ever be true friends, since the inequality between them could never be overcome no matter how much the child does for his parents. This position is rejected by English (1979) and Kristjansson (2006). Generally, contemporary accounts of friendship place less emphasis on equality or similarity of specific traits and more on equality of respect, investment, and commitment. Given the vast range of differences among close friends in talents, interests, and tangible contributions, it would not seem that disabilities pose any general barrier to intimacy. 