state having good laws, but not acting on them. The incontinence
of passion is more curable than that of weakness; what proceeds from
habit more than what is natural (X.).

The Eighth and Ninth Books contain the treatise on Friendship.

The subject deserves a place in an Ethical treatise, because of its
connexion with virtue and with happiness. Several questions have been
debated concerning Friendship,--Is it based on likeness or unlikeness?
Can bad men be friends? Is there but one species of Friendship, or more
than one? (I.) Some progress towards a solution of these questions may
be made by considering what are the objects of liking; these are the
good, the pleasant, the useful. By the good is not meant the absolute
good of Plato, but the apparent good. Inanimate things must be
excluded, as wanting reciprocation (II.). The varieties of friendship
follow these three modes of the likeable. The friendships for the
useful and the pleasant, are not disinterested, but self-seeking; they
are therefore accidental and transitory; they do not involve intimate
and frequent association. Friendship for the good, and between the
virtuous, is alone perfect; it is formed slowly, and has the requisites
of permanence. It occurs rarely (III.). As regards the useful and the
pleasant, the bad may be friends. It may happen that two persons are
mutually pleasant to each other, as lover and beloved; while this
lasts, there is friendship. It is only as respects the good, that there
exists a permanent liking for the person. Such friendship is of an
absolute nature; the others are accidental (IV.). Friendship is in full
exercise only during actual intercourse; it may exist potentially at a
distance; but in long absence, there is danger of its being dissolved.
Friendship is a settled state or habit, while fondness is a mere
passion, which does not imply our wishing to do good to the object of
it, as friendship does (V.). The perfect kind of friendship, from its
intensity, cannot be exercised towards more than a small number. In
regard to the useful and the pleasant, on the other hand, there may be
friendship with many; as the friendship towards tradesmen and between
the young. The happy desire pleasant friends. Men in power have two
classes of friends; one for the useful, the other for the pleasant.
Both qualities are found in the good man; but he will not be the friend
of a superior, unless he be surpassed (by that superior) in virtue
also. I