Now the significance of the entry of outside males would be vast, from many points of view. In a general sense we here find that further aggregation of numbers in unison which we considered important, as prophetic of the present social condition of to-day. Again, there arises a renewed distinction of that difference as between one female and another, so peculiar to mankind. For here we see that for the first time a sister no longer ranks in exactly the same line, from a marital point of view, as a mother. A daughter, in fact, may now evidently have as mate other than the husband-father. As the primitive mind habituated itself to this idea, the first serious blow was dealt at the old parental prerogative. Again, in other ways, in other minds than own brother and sister, will this change in the old order of things be thus brought home—to no one more clearly than to the outside suitor himself, when, later, he becomes a father; the trains of circumstances leading to it are very curious, but would arise in a perfectly natural manner. The result in this connection would make itself felt by him in the next generation, with the advent to the adult stage of his own female offspring.
Is it credible, indeed, that the original male members of a group who had solely accepted his entry as mate for those ineligible females, their sisters, would consent to his further participation in marital right with other female group members? Evidently not: for thus the sexual prerogatives of the strangers would be much greater than their own—for the resident males are barred by the primal law from the wives of the new comers, who yet, as resident females, form probably much the most numerous section of the feminine element in the horde. If the new comers further inherited the ordinary right of intercourse with their own daughters, who would be correspondingly numerous, then the extent of their rights would entirely outbalance that of their brothers-in-law. As original residents the latter would, however, be the law-makers, and we can have no doubt as to what form in such a case law would take.[3] Thus is struck a blow again, however indirect, to incest as a custom, a blow whose power would be the more effective, insomuch as here it is the living father himself, in the outside suitor, who would be in cause. But even admitting that it is possible to conceive a complacency in regard to such participation in sexual rights on the part of the brother, there would still be another much more formidable obstacle to incestuous license as regards his daughter confronting the male intruder in the person of the precedent sister, now his wife.
A psychological factor of enormous power was now for the first time in the history of the world to make itself felt. It would be the play of the natural feeling of sexual jealousy on the part of his resident female mate. The jealousy of a woman, in fact, is at length able to make its strength appear, to some purpose. As a wife who had not been captured, who, in fact, as an actual member of the group itself, was, so to speak, the capturer, her position in regard to her dependent husband would be profoundly modified in comparison with that of the ordinary captive female. Whereas such a captive, seized by the usual process of hostile capture, had been a mere chattel utterly without power; she, as a free agent in her own home, with her will backed by that of her brothers, could impose law on her subject spouse, and such law dictated by jealousy would undoubtedly ordain a bar to intercourse between him and her more youthful, and hence more attractive, daughter.
By these then, and other incidents, each of vast value, we may perceive how the primitive mind became gradually prepared for a change so imperatively necessary for all future progress, and how a habit even so deeply ingrafted as incest may primarily have been forced to slacken its hold. It is even possible to imagine how from such a point of departure, the custom might at once have entirely ceased among all, or at least a portion of, mankind. If we could conceive at this stage a secession from their original group of its resident component females, accompanied by their outside mates, with a continuance of the acceptance of the subordinate strange suitors in future generations of the new colony, then we could admit the probability of rapid evolution in approach to a well-known actual group formation. The persistent importation of the always dependent outsider would accentuate the movement already begun against incest—with two such associations in unison, cousinship would be recognised, and peaceful connubium in 'cross-cousin' marriage between groups would become a habit, and female descent the rule.[4] But at such a stage in social evolution, it is impossible to accept the dominance of the unsupported female or 'feme sole.' Gynæcocracy, if it has indeed ever existed, is evidently as yet incredible. Not thus was dealt the final fatal blow at this last great trait of archaism. We must rather seek it in the familiar economy of the type of group we have left, which is characterised, as with other animals, by the predominance of the male.
In our study of the various incidents in primitive social economy which would have had effect in a sense inimical to the custom of incest, we have only considered the matter from the point of view of the entry of the outside suitor after the death of the paternal tyrant. The incestuous rights of the living group-fathers are thereby in no way directly affected. In the absence of any direct personal interest in the matter on the part of the group-sons, the only other male components and law-makers might indeed continue to remain unopposed indefinitely. Thus a resolution of the problem of decay of incest would seem as far off as ever. Happily this is not in reality the case—the real significance of the entry of the outsider, even on such terms as we have examined, lay in the co-ordination of movement of these resultant primary checks, and the inevitable synchronous evolution of the most characteristic feature of the next and higher type of group, as in itself a mere component of a tribe. The outsider's admission, in fact, really contained the germ of progress in group formation which was to entail the total required decay [of incest].
Up to the present, although the entire male element in a group was divided into two classes, by generations whose interests had little in common, between them no antagonism had arisen which could not be appeased by the evolution of such a law in remedy as we have noted. The case would now be altered; an irreconcilable breach was about to divide them. It will be seen that the advent of the outsider had been a real portent. Where, for instance, and under the circumstances we have portrayed, he had become a more accustomed figure as an immigrant, he would form a valuable connecting link between groups. Each would certainly possess some females seized from the other by more or less forcible capture, but each now possessed a certain proportion of these males, brothers of those females, whose intrusion had been peaceably accepted. With less strained relations and greater intercourse, capture would become a little more rare, and a friendly interchange of women more common. There would be then discovered by the brother a hitherto undreamt-of virtue in the young female, his sister; in fact, her value as a negotiable article would appear.
As brothers and sisters, and thus barred in union by the primal law, their relative interest in each other had been of the feeblest in the past. The ultimate destiny of the sister might be a matter of the most perfect indifference to the brother. With the new order of things she had suddenly become more precious. As an object of barter for the sister of another man, she would show herself to be invaluable. In view of the difficulty and danger attending hostile capture, the temptation to such easy procuration of mates as sister-barter offered would be irresistible. Coming at first into practice when only the death of the father had left his widowed daughter free, its advantages to the sons would impose a gradual encroachment on the rights of possession by the living parent. In prejudice to incest were now opposed the two most powerful passions in human nature, sexual desire, and a love of material gain, and the successful barter of a sister for another man's sister satisfied both. For attempts at capture might be unsuccessful, and purchase might be more or less unsatisfactory. And these passions would be aroused in bosoms able to make their power felt. The sons, as also resident males, would be among the law-makers. However powerful the father in past authority and tradition, in the end the force of numbers would tell. However numerous the group of fathers, they would always be outnumbered by the group of brother sons, and victory would thus ultimately incline to these.[5] However long and doubtful the struggle, as the latter possessed the longer lease of life, the quantum of the exchange value of a sister would always finally be made to show itself, and the determination to profit thereby would be more strongly impressed on each generation.
Natural selection would again certainly come into play in favour of such groups, thus curtailing the monstrous prerogatives of the old-world fathers, by dint of numbers alone. The superiority which would ensue with each generation, would speedily ensure the triumph of that assembly which could definitely accept the presence of the outside suitor. He would come as a multiple unit of strength, a willing ally who would otherwise have been an active enemy—the generator of the productive power to females who would either have remained as sterile residents, or seceded to hostile hordes as breeders of new foes.
Thus, then, we may at length perceive how a custom even so deeply ingrained in nascent man as paternal incest, may finally have become extinct as a custom. In the action of such circumstances we can accept the idea of its ultimate decay and death. By the numerical preponderance of the individuals within a group interested in its disappearance, was alone such a result feasible. This necessary condition we here find fulfilled.