237. No doubt family life as we know it is an institution of gradual growth. It may be found in forms where it is easy to ignore the distinction between it and the life of beasts. It is possible that the human beings with whom it first began--beings 'human' because capable of it--may have been 'descended' from animals not capable of it, i.e. they may have been connected with such animals by certain processes of generation. But this makes no difference in the nature of the capacity itself, which is determined not by a past history but by its results, its functions, that of which it is a capacity. As the foundation of any family life, in the form in which we know it, implies that upon the mere sexual impulse there has supervened on the part of the man a permanent interest in a woman as a person with whom his own well-being is united, and a consequent interest in the children born of her, so in regard to every less perfect form out of which we can be entitled to say that the family life, as we know it, has developed, we must be also entitled to say that it expresses some interest which is in principle identical with that described, however incompletely it has emerged from lower influences.
238. (2) Such an interest being the basis of family relations, it is quite intelligible that everyone actuated by the interest should recognise, and be recognised by, everyone else to whom he ascribes an interest like his own, as entitled to behave towards the objects of the interest--towards his wife and children--in a manner from which everyone else is excluded; that there should thus come to be rights in family relations to a certain privacy in dealing with them; rights to deal with them as his alone and not another's; claims, ratified by the general sense of their admission being for the common good, to exercise certain powers and demand certain forbearances from others, in regard to wife and children. It is only indeed at an advanced stage of reflection that men learn to ascribe to other men, simply as men, the interests which they experience themselves; and hence it is at first only within narrow societies that men secure to each other the due privileges and privacies of family life. In others of the same kin or tribe they can habitually imagine an interest like that of which each feels his own family life to be the expression, and hence in them they spontaneously respect family rights; but they cannot thus practically think themselves into the position of a stranger, and hence towards him they do not observe the same restraints. They do not regard the women of another nation as sacred to the husbands and families of that nation. But that power of making another's good one's own, which in the more intense and individualised form is the basis of family relations, must always at the same time exist in that more diffused form in which it serves as the basis of a society held together by the recognition of a common good. Wherever, therefore, the family relations exist, there is sure to exist also a wider society which by its authority gives to the powers exercised in those relations the character of rights. By what process the relations of husband and wife and the institution of the household may have come to be formed among descendants of a single pair, it is impossible to conceive or to discover, but in fact we find no trace in primitive history of households except as constituents of a clan recognising a common origin; and it is by the customs of the clan, founded on the conception of a common good, that those forbearances on the part of members of one household in dealing with another, which are necessary to the privacy of the several households, are secured.