Now brothers and intimate companions have all in common, but other people have their property separate, and some have more in common and others less, because the Friendships likewise differ in degree. So too do the various principles of Justice involved, not being the same between parents and children as between brothers, nor between companions as between fellow-citizens merely, and so on of all the other conceivable Friendships. Different also are the principles of Injustice as regards these different grades, and the acts become intensified by being done to friends; for instance, it is worse to rob your companion than one who is merely a fellow-citizen; to refuse help to a brother than to a stranger; and to strike your father than any one else. So then the Justice naturally increases with the degree of Friendship, as being between the same parties and of equal extent.
All cases of Communion are parts, so to say, of the great Social one, since in them men associate with a view to some advantage and to procure some of those things which are needful for life; and the great Social Communion is thought originally to have been associated and to continue for the sake of some advantage: this being the point at which legislators aim, affirming that to be just which is generally expedient.
All the other cases of Communion aim at advantage in particular points; the crew of a vessel at that which is to result from the voyage which is undertaken with a view to making money, or some such object; comrades in war at that which is to result from the war, grasping either at wealth or victory, or it may be a political position; and those of the same tribe, or Demus, in like manner.
Some of them are thought to be formed for pleasure’s sake, those, for instance, of bacchanals or club-fellows, which are with a view to Sacrifice