§7. The conjugal relation is, in its origin, of free choice, but when it has once been formed, the duties of affection that arise out of it are commonly thought to be analogous to those arising out of relations of consanguinity. It therefore holds an intermediate position between these latter, and ordinary friendships, partnerships, and associations, which men are equally free to make and to dissolve. Now most associations that men form are for certain definite ends, determined by express contract or tacit understanding: accordingly the duty arising out of them is merely that of fidelity to such contract or understanding, which will be considered later under the heads of Justice and Good Faith. But this does not seem to be the case with what in a strict sense of the term are called Friendships: for although Friendship frequently arises among persons associated for other ends, yet the relation is always conceived to have its end in itself, and to be formed primarily for the development of mutual affection between the friends, and the pleasure which attends this. Still, it is thought that when such an affection has once been formed it creates mutual duties which did not previously exist: we have therefore to inquire how far this is the case, and on what principles these can be determined.
Now here a new kind of difficulty has to be added to those which we have already found in attempting to formulate Common Sense. For we find some who say that, as it is essential to Friendship that the mutual kindly feeling, and the services springing from it, should be spontaneous and unforced, neither the one nor the other should be imposed as a duty; and, in short, that this department of life should be fenced from the intrusion of moral precepts, and left to the free play of natural instinct. Arid this doctrine all would perhaps admit to a certain extent: as, indeed, we have accepted it with regard to all the deeper flow and finer expression of feeling even in the domestic relations: for it seemed pedantic and futile to prescribe rules for this, or even (though we naturally admire and praise any not ungraceful exhibition of intense and genuine affection) to delineate an ideal of excellence for all to aim at. Still, there seemed to be an important sphere of strict duty---however hard to define---in the relations of children to parents, etc., and even in the case of friendship it seems contrary to common sense to recognise no such sphere; as it not unfrequently occurs to us to judge that one friend has behaved wrongly to another, and to speak as if there were a clearly cognisable code of behaviour in such relations.
Perhaps, however, we may say that all clear cases of wrong conduct towards friends come under the general formula of breach of understanding. Friends not unfrequently make definite promises of service, but we need not consider these, as their violation is prohibited by a different and clearer moral rule. But further, as all love is understood to include a desire for the happiness of its object, the profession of friendship seems to bind one to seek this happiness to an extent proportionate to such profession. Now common benevolence (cf. ante, §5) prescribes at least that we should render to other men such services as we can render without any sacrifice, or with a sacrifice so trifling as to be quite out of proportion to the service rendered. And since the profession of friendship though the term is used to include affections of various degree must imply a greater interest in one's friend's happiness than in that of men in general, it must announce a willingness to make more or less considerable sacrifices for him, if occasion offers. If then we decline to make such sacrifices, we do wrong by failing to fulfil natural and legitimate expectations. So far there seems no source of difficulty except the indefiniteness inevitably arising from the wide range of meanings covered by the term Friendship. But further questions arise in consequence of the changes of feeling to which human nature is liable: first, whether it is our duty to resist such changes as much as we can; and secondly, whether if this effort fails, and love diminishes or departs, we ought still to maintain a disposition to render services corresponding to our past affection. And on these points there does not seem to be agreement among moral and refined persons. For, on the one hand, it is natural to us to admire fidelity in friendship and stability of affections, and we commonly regard these as most important excellences of character: and so it seems strange if we are not to aim at these as at all other excellences, as none more naturally stir us to imitation. And hence many would be prepared to lay down that we ought not to withdraw affection once given, unless the friend behaves ill: while some would say that even in this case we ought not to break the friendship unless the crime is very great. Yet, on the other hand, we feel that such affection as is produced by deliberate effort of will is but a poor substitute for that which springs spontaneously, and most refined persons would reject such a boon: while, again, to conceal the change of feeling seems insincere and hypocritical.
But as for services, a refined person would not accept such from a former friend who no longer loves him: unless in extreme need, when any kind of tie is, as it were, invigorated by the already strong claim which common humanity gives each man upon all others. Perhaps, therefore, there cannot be a duty to offer such services in any case, when the need is not extreme. Though this inference is not quite clear: for in relations of affection we often praise one party for offering what we rather blame the other for accepting. But it seems that delicate questions of this kind are more naturally referred to canons of good taste and refined feeling than of morality proper: or at least only included in the scope of morality in so far as we have a general duty to cultivate good taste and refinement of feeling, like other excellences.
On the whole, then, we may say that the chief difficulties in determining the moral obligations of friendship arise (1) from the indefiniteness of the tacit understanding implied in the relation, and (2) from the disagreement which we find as to the extent to which Fidelity is a positive duty. It may be observed that the latter difficulty is especially prominent in respect of those intimacies between persons of different sex which precede and prepare the way for marriage.