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?
I do not think that this question can be correctly answered in more than one way. We have first to find out the causes of the social phenomena; then, from the prevalence of the causes, we may infer the prevalence of the phenomena themselves, if the former must be assumed to have operated without being checked by other causes.
If, then, historical researches based on ethnography are to be crowned with success, the first condition is that there shall be a rich material. It is only by comparing a large number of facts that we may hope to find the cause or causes on which a social phenomenon is dependent. And a rich material is all the more indispensable, as the trustworthiness of ethnographical statements is not always beyond dispute. Without a thorough knowledge of a people it is impossible to give an exact account of its habits and customs, and therefore it often happens that the statements of a traveller cannot, as regards trustworthiness, come up to the evidences of history. As the sociologist is in many cases unable to distinguish falsehood from truth, he must be prepared to admit the inaccuracy of some of the statements he quotes. What is wanting in quality must be made up for in quantity; and he who does not give himself the trouble to read through a voluminous literature of ethnography should never enter into speculations on the origin and early development of human civilization.