[465] _Ibid._, 264-66. On the influence of ancestor-worship and the sense of propriety, see WAKE, _op. cit._, chaps. vii and xii, 227 ff., 234, 435 ff. _Cf._ SPENCER, _op. cit._, I, 691, 697; and on monogamy, LETOURNEAU, _L'évolution du mariage_, chaps. xix, ii; POST, _Familienrecht_, 72 ff. So we come back to the starting-point. The complex phenomena of human sexual relations have been examined in the light of scientific criticism and recent research. The result seems unmistakably to show that pairing has always been the typical form of human marriage. Early monogamy takes its rise beyond the border-line separating man from the lower animals. But, considering the aberrations from the type, development has been in a circle.[466] At the dawn of human history individual marriage prevails, though the union is not always lasting. In later stages of advancement, under the influence of property, social organization, social distinctions, and the motives to which they gave rise, various forms of polyandry and polygyny make their appearance, though monogamy as the type is never superseded. "Nothing, indeed, is more favourable to polygyny," says Westermarck, "than social differentiation."[467] In its "highest and regulated form," declares Morgan, "it presupposes a considerable advance of society, together with the development of superior and inferior classes, and of some kinds of wealth."[468] Furthermore there is direct evidence in some cases that a transition from monogamy has actually occurred.[469] At a still more advanced stage of culture, under pressure of those influences which have led to the social elevation of woman, polygyny yields in turn to monogamy. "When the feelings of women are held in due respect, monogamy will necessarily be the only recognized form of marriage. In no way does the progress of mankind show itself more clearly than in the increased acknowledgment of women's rights, and the causes which, at lower stages of development, may make polygyny desired by women themselves, do not exist in highly civilized societies. The refined feeling of love, depending chiefly upon mutual sympathy and upon appreciation of mental qualities, is scarcely compatible with polygynous habits; and the passion for one has gradually become more absorbing."[470] But the later monogamy differs from the earlier in one important characteristic. The primitive monogamy "is not a form of marriage which can be regarded as the expression of a marriage law; that is, it is not a form of marriage which is striving for the mastery, and which cannot tolerate other co-existent forms of marriage. On the other hand the later monogamy, which arises from a distinct condemnation of polygamy, or from a secret aversion to it, is characterized by self-assertion, and seeks to exclude other forms of marriage."[471]