(3) Another cause, after slavery became developed, was the high value set on women as laborers. Among many barbarous peoples the women do the main part of the work. They are more tractable as slaves, and consequently a high value is set upon their labor. As we have already seen, these female slaves usually serve at the same time as concubines, if not legal wives of their masters.

(4) Another cause which we can perhaps hardly appreciate at the present time is the high valuation set on children. We see this cause operating particularly in the case of the patriarchs of the Old Testament. Under the patriarchal family great value was set upon children as necessary to continue the family line. Where the device of adoption was not resorted to, therefore, in case of barrenness or the birth exclusively of female children, nothing was more natural than that polygyny should be resorted to in order to insure the family succession. In the patriarchal family also a high valuation was necessarily set upon children, because the larger the family grew the stronger it was.

(5) Finally, religion came to sanction polygyny. The religious sanction of polygyny cannot be looked upon as one of its original causes, but when once established it reacted powerfully to reenforce and maintain the institution. How the religious sanction came about we can readily see when we remember that very commonly religions confuse the practice of the nobility with what is noble or commendable morally. The polygynous practices of the nobility, therefore, under certain conditions came to receive the sanction of religion. When this took place polygyny became firmly established as a social institution, very difficult to uproot, as all the experience of Christian missionaries among peoples practicing polygyny goes to show. We may note also the general truth, that while religion does not originate human institutions or the forms of human association, it is preeminently that which gives fixity and stability to institutions through the supernatural sanction that it accords them.

Some judgment of the social value of polygyny may not be out of place in connection with this subject. Admitting, as all students of social history must, that in certain times and places the polygynous form of family has been advantageous, has served the interests of social survival and even of civilization, yet viewed from the standpoint of present society it seems that our judgment of polygyny must be wholly unfavorable. In the first place, as we have already seen, polygyny is essentially an institution of barbarism. It arose largely through the practice of wife capture and the keeping of female slaves. While often adjusted to the requirements of barbarous societies, it seems in no way adjusted to a high civilization. Polygyny, indeed, must necessarily rest upon the subjection and degradation of women. Necessarily the practice of polygyny must disregard the feelings of women, for women are jealous creatures as well as men. No high regard for the feelings of women, therefore, would be consistent with the practice of polygyny. Finally, all the evidence that we have goes to show that under polygyny children are neglected, and, at least from the standpoint of a high civilization, inadequately socialized. This must necessarily be so, because in the polygynous family the care of the children rests almost entirely with the mother. While we have no statistics of infant mortality from polygynous countries, it seems probable that infant mortality is high, and we know from experience with polygynous families in our own state of Utah, according to the testimony of those who have worked among them, that delinquent children are especially found in such households. Fatherhood, in the full sense of the word, can hardly be said to exist under polygyny.

Those philosophers, like Schopenhauer, who advocate the legalizing of polygyny in civilized countries, are hardly worth replying to. It is safe to say that any widespread practice of polygyny in civilized communities would lead to a reversion to the moral standards of barbarism in many if not in all matters. That polygyny is still a burning question in the United States of the twentieth century is merely good evidence that we are not very far removed yet from barbarism.

MONOGAMY, as we have already seen, has been the prevalent form of marriage in all ages and in all countries. Wherever other forms have existed monogamy has existed alongside of them as the dominant, even though perhaps not the socially honored, form. All other forms of the family must be regarded as sporadic variations, on the whole unsuited to long survival, because essentially inconsistent with the nature of human society. In civilized Europe monogamy has been the only form of the family sanctioned for ages by law, custom, and religion. The leading peoples of the world, therefore, practice monogamy, and it is safe to say that the connection between monogamy and progressive forms of civilization is not an accident.

What, then, are the social advantages of monogamy which favor the development of a higher type of culture? These advantages are numerous, but perhaps the most important of them can be grouped under six heads.

(1) The number of the two sexes, as we have already seen, is everywhere approximately equal. This means that monogamy is in harmony with the biological conditions that exist in the human species. The equal number of the two sexes has probably been brought about through natural selection. Why nature should favor this proportion of the sexes can perhaps be in part understood when we reflect that with such proportion there can be the largest number of family groups, and hence the best possible conditions for the rearing of offspring.

(2) Monogamy secures the superior care of children in at least two respects. First, it very greatly decreases mortality in children, because under monogamy both husband and wife unite in their care. Again, monogamy secures the superior upbringing and, therefore, the superior socialization of the child. In the monogamous family much greater attention can be given to the training of children by both parents. In other forms of the family not only is the death rate higher among children, but from the point of view of modern civilization, at least, they are inferiorly socialized.

(3) The monogamic family alone produces affections and emotions of the higher type. It is only in the monogamic family that the highest type of altruistic affection can be cultivated. It is difficult to understand, for example, how anything like unselfish affection between husband and wife can exist under polygyny. Under monogamy, husband and wife are called upon to sacrifice selfish desires in the mutual care of children. Monogamy is, therefore, fitted as a form of the family to foster altruism in the highest degree, and, as we have seen, the higher the type of altruism produced by the family life, the higher the type of the social life generally, other things being equal. It is especially to the credit of monogamy that it has created fatherhood in the fullest sense of the term, and therefore taught the male element in human society the value of service and self-sacrifice. Under polygynous conditions the father cannot devote himself to any extent to his children or to any one wife, since he is really the head of several households, and therefore, as we have already noted, fatherhood in the fullest sense scarcely exists under polygyny.