Nicomachean Ethics

Now of course all Friendship is based upon Communion, as has been already stated: but one would be inclined to separate off from the rest the Friendship of Kindred, and that of Companions: whereas those of men of the same city, or tribe, or crew, and all such, are more peculiarly, it would seem, based upon Communion, inasmuch as they plainly exist in right of some agreement expressed or implied: among these one may rank also the Friendship of Hospitality,

The Friendship of Kindred is likewise of many kinds, and appears in all its varieties to depend on the Parental: parents, I mean, love their children as being a part of themselves, children love their parents as being themselves somewhat derived from them. But parents know their offspring more than these know that they are from the parents, and the source is more closely bound to that which is produced than that which is produced is to that which formed it: of course, whatever is derived from one’s self is proper to that from which it is so derived (as, for instance, a tooth or a hair, or any other thing whatever to him that has it): but the source to it is in no degree proper, or in an inferior degree at least.

Then again the greater length of time comes in: the parents love their offspring from the first moment of their being, but their offspring them only after a lapse of time when they have attained intelligence or instinct. These considerations serve also to show why mothers have greater strength of affection than fathers.

Now parents love their children as themselves (since what is derived from themselves becomes a kind of other Self by the fact of separation), but children their parents as being sprung from them. And brothers love one another from being sprung from the same; that is, their sameness with the common stock creates a sameness with one another;[7] whence come the phrases, “same blood,” “root,” and so on. In fact they are the same, in a sense, even in the separate distinct individuals.

Then again the being brought up together, and the nearness of age, are a great help towards Friendship, for a man likes one of his own age and persons who are used to one another are companions, which accounts for the resemblance between the Friendship of Brothers and that of Companions.

And cousins and all other relatives derive their bond of union from these, that is to say, from their community of origin: and the strength of this bond varies according to their respective distances from the common ancestor.

Further: the Friendship felt by children towards parents, and by men towards the gods, is as towards something good and above them; because these have conferred the greatest possible benefits, in that they are the causes of their being and being nourished, and of their having been educated after they were brought into being.

And Friendship of this kind has also the pleasurable and the profitable more than that between persons unconnected by blood, in proportion as their life is also more shared in common. Then again in the Fraternal Friendship there is all that there is in that of Companions, and more in the good, and generally in those who are alike; in proportion as they are more closely tied and from their very birth have a feeling of affection for one another to begin with, and as they are more like in disposition who spring from the same stock and have grown up together and been educated alike: and besides this they have the greatest opportunities in respect of time for proving one another, and can therefore depend most securely upon the trial.

Between Husband and Wife there is thought to be Friendship by a law of nature: man being by nature disposed to pair, more than to associate in Communities: in proportion as the family is prior in order of time and more absolutely necessary than the Community. And procreation is more common to him with other animals; all the other animals have Communion thus far, but human creatures cohabit not merely for the sake of procreation but also with a view to life in general::[8] because in this connection the works are immediately divided, and some belong to the man, others to the woman: thus they help one the other, putting what is peculiar to each into the common stock.

And for these reasons this Friendship is thought to combine the profitable and the pleasurable: it will be also based upon virtue if they are good people; because each has goodness and they may take delight in this quality in each other. Children too are thought to be a tie: accordingly the childless sooner separate, for the children are a good common to both and anything in common is a bond of union.

The question how a man is to live with his wife, or (more generally) one friend with another, appears to be no other than this, how it is just that they should: because plainly there is not the same principle of Justice between a friend and friend, as between strangers, or companions, or mere chance fellow-travellers.