Books eight and nine of Nicomachean Ethics begin with
evaluating what makes a relationship a friendship. The most prominent quality
is a friend wishes good will for the sake of the other. Also, the good will
must be mutually recognized and reciprocated. This good will is closely tied to
the practice of moral virtues. Aristotle identifies three relationships between
friends. The first two, friendships of utility and pleasure, are short lived
and exist for the purpose of an exchange between the friends. They happen
accidentally arising from a need that the involved parties can meet. This is
not a perfect friendship, but is merely a shadow reflecting the relationship
between true friends. A perfect friendship is based on each person’s qualities
of excellence. It is enduring because its foundation is set in characteristics
that do not change.
Within a perfect friendship, the benefits
of a utility or pleasure friendship can also be present. Because true friends
love for the sake of the other, they will naturally be inclined to offer benefits
like in an associations of utility. Also, out of love for the goodness of the
person, they will receive pleasure from each other as well. Aristotle describes
the importance of friends as such: “friends help young men avoid error; to
older people they give the care and help needed to supplement the failing
powers of action which infirmity brings in its train; and to those in their
prime they give the opportunity to preform noble actions.” In
this way, friends contribute to eudaimonia not just from the benefits and
pleasure received, but also because, like in the polis, it provides a structure
under which to practice virtuous actions.