_Readings_.--_Contra Gentes_, iii., 122; _ib_., iii., 126; _ib_., iii., 136; Devas, _Studies of Family Life_, §§ 90-101, where he disposes of the proof of primitive promiscuity, drawn from the fact that in early societies kinship is traced and property claimed only through the mother. SECTION II.--_Of the Unity of Marriage_. 1. _Both man and woman are by nature incapable of a second marriage, while their former marriage endures_. No woman can have two husbands at the same time, which is _polyandry_; and no man can have two wives at the same time, which is _polygamy_. The second marriage attempted is not only _illicit_, but _invalid_: it is no contract, no marriage at all, and all cohabitation with the second partner is sheer adultery. This is a great deal more than saying that polyandry and polygamy are unlawful. 2. That is by nature no marriage, which is inconsistent with the natural ends of marriage, _offspring_ and _mutual faith_. But polyandry is thus inconsistent with the good of offspring, and polygamy with mutual faith. It is not meant that polyandry makes the birth of children impossible. But nature is solicitous, not for the mere birth, but for the rearing and good estate of the child born. Now a child born fatherless is in an ill plight for its future education. Posthumous children in lawful wedlock are born fatherless: that is a calamity: but what shall we think of an institution which makes that calamity to the child sure always to occur? Such an institution is polyandry. For in it no man can ever know his own child, except by likeness, and likeness in a baby face is largely as you choose to fancy it. Again, is the polyandrous wife to be, or not to be, the head of the family? If not, the family--for it ought to be one family, where there is one mother--will have as many heads as she has husbands, a pretty specimen of a house divided against itself. If she is to be the head, that is a perversion of the natural order of predominance between the sexes. In any case, polyandry is little better than promiscuity: it is fatal to the family and, fatal to the race; and children born of it are born out of marriage. 3. Against polygamy the case in natural law is not quite so strong as against polyandry. Still it is a strong case enough in the interest of the wife. The words spoken by the bride to the bridegroom in the marriage rite of ancient Rome, _Ubi tu Caius, ego Caia_, "Where you are master, I am mistress," declare the relation of _mutual faith_ as it should be, namely, a relation of equality, with some advantage, preference, and pre-eminence allowed to the husband, yet not so great advantage as to leave _him_ free where _she_ is straitly bound, and reduce her to the servile level of one in a row of minions to his passion and sharers of his divided affections. Polygamy in all ages has meant the lowering of womankind: He will hold thee-- Something better than his dog, a little dearer than his horse