I can now turn to the second line of attack, that which boldly discards the origin of the terminology of relationship in social conditions, and seeks for its explanation in psychology. The line of argument I propose to follow is first to show that many details of classificatory systems have been directly determined by social factors. If that task can be accomplished, we shall have firm ground from which to take off in the attempt to refer the general characters of the classificatory and other systems of relationship to forms of social organisation. Any complete theory of a social institution has not only to account for its general characters, but also for its details, and I propose to begin with the details.
I must first return to the history of the subject, and stay for a moment to ask why the line of argument I propose to follow was not adopted by Morgan and has been so largely disregarded by others.
Whenever a new phenomenon is discovered in any part of the world, there is a natural tendency to seek for its parallels elsewhere. Morgan lived at a time when the unity of human culture was a topic which greatly excited ethnologists, and it is evident that one of his chief interests in the new discovery arose from the possibility it seemed to open of showing the uniformity of human culture. He hoped to demonstrate the uniformity of the classificatory system throughout the world, and he was content to observe certain broad varieties of the system and refer them to supposed stages in the history of human society. He paid but little attention to such varieties of the classificatory system as are illustrated in his own record of North American systems, and seems to have overlooked entirely certain features of the Indian and Oceanic systems he recorded, which might have enabled him to demonstrate the close relation between the terminology of relationship and social institutions. Morgan’s neglect to attend to these differences must be ascribed in some measure to the ignorance of rude forms of social organisation which existed when he wrote, but the failure of others to recognise the dependence of the details of classificatory systems upon social institutions is rather to be ascribed to the absence of interest in the subject induced by their adherence to McLennan’s primary error. Those who believe that the classificatory system is merely an unimportant code of mutual salutations are not likely to attend to relatively minute differences in the customs they despise. The credit of having been the first fully to recognise the social importance of these differences belongs to J. Kohler. In his book “Zur Urgeschichte der Ehe,” which I have already mentioned, he studied minutely the details of many different systems, and showed that they could be explained by certain forms of marriage practised by those who use the terms. I propose now to deal with classificatory terminology from this point of view. My procedure will be first to show that the details which distinguish different forms of the classificatory system from one another have been directly determined by the social institutions of those who use the systems, and only when this has been established, shall I attempt to bring the more general characters of the classificatory and other systems into relation with social institutions.
I am able to carry out this task more fully than has hitherto been possible because I have collected in Melanesia a number of systems of relationship which differ far more widely from one another than those recorded in Morgan’s book or others which have been collected since. Some of the features which characterise these Melanesian systems will be wholly new to ethnologists, not having yet been recorded elsewhere, but I propose to begin with a long familiar mode of terminology which accompanies that widely distributed custom known as the cross-cousin marriage. In the more frequent form of this marriage a man marries the daughter either of his mother’s brother or of his father’s sister; more rarely his choice is limited to one of these relatives.
Such a marriage will have certain definite consequences. Let us take a case in which a man marries the daughter of his mother’s brother, as is represented in the following diagram:
Diagram 1[8]
One consequence of the marriage between C and d will be that A, who before the marriage of C was only his mother’s brother, now becomes also his wife’s father, while b, who before the marriage was the mother’s brother’s wife of C, now becomes his wife’s mother. Reciprocally, C, who before his marriage had been the sister’s son of A and the husband’s sister’s son of b, now becomes their son-in-law. Further, E and f, the other children of A and b, who before the marriage had been only the cousins of C, now become his wife’s brother and sister.