Yet nothing has been more fatal to the Science of Society than the habit of inferring, without sufficient reasons, from the prevalence of a custom or institution among some savage peoples, that this custom, this institution is a relic of a stage of development that the whole human race once went through. Thus the assumption that primitive men lived in tribes or hordes, all the men of which had promiscuous intercourse with all the women, where no individual marriage existed, and the children were the common property of the tribe, is founded, in the first place, on the statements of some travellers and ancient writers as to peoples among whom this custom is said actually to prevail, or to have prevailed. Dr. Post has gone still further in his book, ‘Die Geschlechtsgenossenschaft der Urzeit und die Entstehung der Ehe.’ Without adducing any satisfactory reason for his opinion, he considers it probable that “monogamous marriage originally emerged everywhere from pure communism in women, through the intermediate stages of limited communism in women, polyandry, and polygyny.”[2] Mr. Lewis H. Morgan, in his ‘Systems of Consanguinity and Affinity of the Human Family,’ has suggested no fewer than fifteen normal stages in the evolution of marriage and the family, assuming the existence and general prevalence of a series of customs and institutions “which must of necessity have preceded a knowledge of marriage between single pairs, and of the family itself, in the modern sense of the term.”[3] According to him, one of the first stages in this series is the intermarriage of brothers and sisters, as evidence of which he adduces, besides other facts, the historical statements that one of the Herods was married to his sister, and Cleopatra was married to her brother.[4] Again, in the study of symbols, or survivals, the sociologists have by no means always been so careful as the matter requires. True enough that “wherever we discover symbolical forms, we are justified in inferring that in the past life of the people employing them, there were corresponding realities.”[5] But all depends upon our rightly interpreting these symbols, and not putting into them a foreign meaning. The worst is, however, that many customs have been looked upon as survivals that probably are not so. Thus, for instance, I think that Mr. McLennan is mistaken in considering the system of the Levirate, under which, at a man’s death, his wife or wives pass to his brother, as a test of the former presence of polyandry, the brothers of a family having a common wife. Similar conclusions being of common occurrence in modern Sociology, it is not surprising that different writers dissent so frequently from each other. This should be a strong reason for every conscientious investigator first of all putting to himself the question: how can we from ethnographical facts acquire information regarding the early history of mankind?