91. Geographic Distribution
Thus it appears that it is not always easy to settle the origin and history of the phenomena of culture. Evidently, many facts must be taken into consideration: above all, geographic distribution. Because a habit is so well ingrained in our life as to seem absolutely natural and almost congenital, it does not follow that it really is so. The vast majority of culture elements have been learned by each nation from other peoples, past and present. At the same time there are unexpected limits to the principle of borrowing. Transmission often operates over vast areas and for long periods but at other times ceases.
Two reflections arise. The first is the discouraging but salutary one that the history of civilization and its parts is an intricate matter, not to be validly determined by off-hand guesses. A second conclusion is that the geographic distribution of any culture element is always likely to be a fact of prime importance about it. It is because the Basques and the Brazilian Indians are geographically separate that there is fair prima facie probability of the couvade being the result of independent origin. It is because of another geographic fact, that proverbs are known throughout one hemisphere and lacking from the other, that it must be inferred that they represent a borrowed culture trait.
In the following pages a number of culture elements will be examined from the point of view of their distribution with the aim of determining how far each of the two principles of parallel invention and of borrowing may be inferred to have been operative in regard to them. In place of “independent origin” the terms “parallelism” or “convergence” will be generally used. As an equivalent of “borrowing” the somewhat less metaphorical word “diffusion” will be applied. Well known historic cases of diffusion, such as those of Christianity and Mohammedanism, of Roman law, of the printing press and steam engine and of the great modern mechanical inventions, will not be considered. It is however well to keep these numerous cases in the background of one’s mind as a constant suggestion that the principle of diffusion is an extremely powerful one and still active. In fact, the chief reason why early anthropologists did not make more use of this principle seems to have been their extreme familiarity with it. It was going on all about them, so that in dealing with prehistoric times or with remote peoples, they tended to overlook it. This was perhaps a natural error, since the communications of savages and their methods of transmission are so much more restricted than our own. Yet of course even savages shift their habitations and acquire new neighbors. At times they capture women and children from one another. Again they intermarry; and they almost invariably maintain some sort of trade relations with at least some of the adjacent peoples. Slow as diffusion might therefore be among them, it would nevertheless go on, and its lack of rapidity would be compensated by the immense durations of time in the prehistoric period. It is certain that the simpler inventions of primitive man generally did not travel with the rapidity of the printing press and telegraph and camera. But on the other hand, instead of a generation or a century, there would often be periods of a thousand or five thousand years for an invention or a custom to spread from one continent to another. There is thus every a priori reason why diffusion could be expected to have had a very large part in the formation of primitive and barbarous as well as advanced culture.