friendships till men's characters and years have arrived at their full
strength and development. People must not, for instance, regard as fast
friends all whom in their youthful enthusiasm for hunting or football
they liked for having the same tastes. By that rule, if it were a mere
question of time, no one would have such claims on our affections as
nurses and slave-tutors. Not that they are to be neglected, but they
stand on a different ground. It is only these mature friendships that
can be permanent. For difference of character leads to difference of
aims, and the result of such diversity is to estrange friends. The sole
reason, for instance, which prevents good men from making friends with
bad, or bad with good, is that the divergence of their characters and
aims is the greatest possible.

Another good rule in friendship is this: do not let an excessive
affection hinder the highest interests of your friends. This very
often happens. I will go again to the region of fable for an instance.
Neoptolemus could never have taken Troy if he had been willing to listen
to Lycomedes, who had brought him up, and with many tears tried to
prevent his going there. Again, it often happens that important business
makes it necessary to part from friends: the man who tries to baulk it,
because he thinks that he cannot endure the separation, is of a weak
and effeminate nature, and on that very account makes but a poor friend.
There are, of course, limits to what you ought to expect from a friend
and to what you should allow him to demand of you. And these you must
take into calculation in every case.

21. Again, there is such a disaster, so to speak, as having to break off
friendship. And sometimes it is one we cannot avoid. For at this point
the stream of our discourse is leaving the intimacies of the wise and
touching on the friendship of ordinary people. It will happen at times
that an outbreak of vicious conduct affects either a man's friends
themselves or strangers, yet the discredit falls on the friends. In
such cases friendships should be allowed to die out gradually by an
intermission of intercourse. They should, as I have been told that Cato
used to say, rather be unstitched than toni in twain; unless, indeed,
the injurious conduct be of so violent and outrageous a nature as
to make an instant breach and separation the only possible course
consistent with honour and rectitude. Again, if a change in character
and aim takes p