Westermarck, op. cit., vol. i, p. 19.
See, e.g., "Exogamy and the Mating of Cousins," in Essays Presented to E. B. Tylor, 1907, p. 53. "In many departments of primitive life we find a naïve desire to, as it were, assist Nature, to affirm what is normal, and later to confirm it by the categorical imperative of custom and law. This tendency still flourishes in our civilized communities, and, as the worship of the normal, is often a deadly foe to the abnormal and eccentric, and too often paralyzes originality."
The spirit of Christianity, as illustrated by Paulinus, in his Epistle XXV, was from the Roman point of view, as Dill remarks (Roman Society, p. 11), "a renunciation, not only of citizenship, but of all the hard-won fruits of civilization and social life."