Self-interest therefore, no less than the natural sympathy between fathers and children, as well as between members of the same group (quite apart from forays and fighting), must have tended to bring about a change in the laws of descent.
The late Major J.W. Powell has already described the transition from matria potestas to patria potestas among the Pueblo peoples. He put it down to economic conditions, which lead the groups to scatter, each under the headship of a male, who is also the husband; this naturally resulted in a weakening of the influence of the mother’s brother. It is, however, less clear that it would bring about the decay of the power of the mother herself, which in Australian tribes, at any rate, seems to be independent of the support she obtains from her male relatives.
In Australia, as we have seen, the change from matria to patria potestas had but little influence in bringing about a change in the rule of descent. Here, too, the change in the rule of descent may be put down in the main to economic causes also in a broad sense. Dumping was not in those days a question of practical politics; the problem was to prevent the neighbours from pursuing the policy of the free and open port. The necessity of protecting tribal and group property in land and game would naturally tend to bind men closer and closer, in proportion as the pressure from without became greater. It is perhaps hardly accidental that the main area of male descent is that which has also developed the Intichiuma ceremonies.
If Prof. Gregory’s view that the occupation of Victoria by the natives dates back no more than 300 years is correct, we may perhaps see in the migration one cause of the rise of patriliny. Anything which tended to shake the influence of the mother’s kin would increase the father’s power; and the need of protecting newly established groups from the incursions of their neighbours would be more urgent than in older districts. As we have seen, the first mentioned cause has elsewhere had little direct effect; but it may well have played a larger part under the novel conditions of migration and occupation of fresh territory.
In South Queensland the fractionation of tribes seems to have gone further than elsewhere, unless we suppose that we have here an area, where, as in California, pressure from without has crowded together the remnants of many tribes. Although it is not obvious how the multiplication of distinct tribes has favoured patrilineal descent, we may, at any rate, say that the conditions in the area are exceptional; possibly it was more fruitful than the greater part of the continent; if so personal property in the shape of trees, etc., which we have already seen in existence in this area, would play a more important role here, and may well have determined the transition to patrilineal descent.