Aristotle, Nicomachean Ethics
H. Rackham, Ed.

Friendship based on pleasure has a similarity to friendship based on virtue, for good men are pleasant to one another; and the same is true of friendship based on utility, for good men are useful to each other. In these cases also the friendship is most lasting when each friend derives the same benefit, for instance pleasure, from the other, and not only so, but derives it from the same thing, as in a friendship between two witty people, and not as in one between a lover and his beloved. These do not find their pleasure in the same things: the lover's pleasure is in gazing at his beloved, the loved one's pleasure is in receiving the attentions of the lover; and when the loved one's beauty fades, the friendship sometimes fades too, as the lover no longer finds pleasure in the sight of his beloved, and the loved one no longer receives the attentions of the lover; though on the other hand many do remain friends if as a result of their intimacy they have come to love each other's characters, both being alike in character. [2] But when a pair of lovers exchange not pleasure for pleasure but pleasure for gain, the friendship is less intense and less lasting.

A friendship based on utility dissolves as soon as its profit ceases; for the friends did not love each other, but what they got out of each other.

Friendships therefore based on pleasure and on and utility can exist between two bad men, between one bad man and one good, and between a man neither good nor bad and another either good, bad, or neither. But clearly only good men can be friends for what they are in themselves; since bad men do not take pleasure in each other, save as they get some advantage from each other. [3]

Also friendship between good men alone is proof against calumny; for a man is slow to believe anybody's word about a friend whom he has himself tried and tested for many years, and with them there is the mutual confidence, the incapacity ever to do each other wrong, and all the other characteristics that are required in true friendship. Whereas the other forms of friendship are liable to be dissolved by calumny and suspicion. [4]

But since people do apply the term ‘friends’ to persons whose regard for each other is based on utility, just as states can be ‘friends’ （since expediency is generally recognized as the motive of international alliances）, or on pleasure, as children make friends, perhaps we too must call such relationships friendships; but then we must say that there are several sorts of friendship, that between good men, as good, being friendship in the primary and proper meaning of the term, while the other kinds are friendships in an analogical sense,¹ since such friends are friends in virtue of a sort of goodness and of likeness² in them: insomuch as pleasure is good in the eyes of pleasure-lovers. [5] But these two secondary forms of friendship are not very likely to coincide: men do not make friends with each other both for utility and for pleasure at the same time, since accidental qualities are rarely found in combination.