Other writers have on the contrary assumed, and evidently with more right, that exogamy is to be interpreted as an institution for the prevention of incest[178].
If we survey the gradually increasing complication of Australian marriage restrictions we can hardly help agreeing with the opinion of Morgan Frazer, Hewitt and Baldwin Spencer[179], that these institutions bear the stamp of ‘deliberate design’, as Frazer puts it, and that they were meant to do what they have actually accomplished. “In no other way does it seem possible to explain in all its details a system at once so complex and so regular”[180].
It is of interest to point out that the first restrictions which the introduction of marriage classes brought about affected the sexual freedom of the younger generation, in other words, incest between brothers and sisters and between sons and mothers, while incest between father and daughter was only abrogated by more sweeping measures.
However, to trace back exogamous sexual restrictions to legal intentions does not add anything to the understanding of the motive which created these institutions. From what source, in the final analysis, springs the dread of incest which must be recognized as the root of exogamy? It evidently does not suffice to appeal to an instinctive aversion against sexual intercourse with blood relatives, that is to say, to the fact of incest dread, in order to explain the dread of incest, if social experience shows that, in spite of this instinct, incest is not a rare occurrence even in our society, and if the experience of history can acquaint us with cases in which incestuous marriage of privileged persons was made the rule.
Westermarck[181] advanced the following to explain the dread of incest: “that an innate aversion against sexual intercourse exists between persons who live together from childhood and that this feeling, since such persons are as a rule consanguineous, finds a natural expression in custom and law through the abhorrence of sexual intercourse between those closely related.” Though Havelock Ellis disputed the instinctive character of this aversion in the Studies in the Psychology of Sex, he otherwise supported the same explanation in its essentials by declaring: “The normal absence of the manifestation of the pairing instinct where brothers and sisters or boys and girls living together from childhood are concerned, is a purely negative phenomenon due to the fact that under these circumstances the antecedent conditions for arousing the mating instinct must be entirely lacking.... For persons who have grown up together from childhood habit has dulled the sensual attraction of seeing, hearing and touching and has led it into a channel of quiet attachment, robbing it of its power to call forth the necessary erethistic excitement required to produce sexual tumescence.”
It seems to me very remarkable that Westermarck looks upon this innate aversion to sexual intercourse with persons with whom we have shared childhood as being at the same time a psychic representative of the biological fact that inbreeding means injury to the species. Such a biological instinct would hardly go so far astray in its psychological manifestation as to affect the companions of home and hearth which in this respect are quite harmless, instead of the blood relatives which alone are injurious to procreation. And I cannot resist citing the excellent criticism which Frazer opposes to Westermarck’s assertion. Frazer finds it incomprehensible that sexual sensibility to-day is not at all opposed to sexual intercourse with companions of the hearth and home while the dread of incest, which is said to be nothing but an offshoot of this reluctance, has nowadays grown to be so overpowering. But other remarks of Frazer’s go deeper and I set them down here in unabbreviated form because they are in essential agreement with the arguments developed in my chapter on taboo.
“It is not easy to see why any deep human instinct should need reinforcement through law. There is no law commanding men to eat and drink, or forbidding them to put their hands in the fire. Men eat and drink and keep their hands out of the fire instinctively, for fear of natural, not legal penalties, which would be entailed by violence done to these instincts. The law only forbids men to do what their instincts incline them to do; what nature itself prohibits and punishes it would be superfluous for the law to prohibit and punish. Accordingly we may always safely assume that crimes forbidden by law are crimes which many men have a natural propensity to commit. If there were no such propensity there would be no such crimes, and if no such crimes were committed, what need to forbid them? Instead of assuming therefore, from the legal prohibition of incest, that there is a natural aversion to incest we ought rather to assume that there is a natural instinct in favour of it, and that if the law represses it, it does so because civilized men have come to the conclusion that the satisfaction of these natural instincts is detrimental to the general interests of society”[182].
To this valuable argument of Frazer’s I can add that the experiences of psychoanalysis make the assumption of such an innate aversion to incestuous relations altogether impossible. They have taught, on the contrary, that the first sexual impulses of the young are regularly of an incestuous nature and that such repressed impulses play a rôle which can hardly be overestimated as the motive power of later neuroses.
The interpretation of incest dread as an innate instinct must therefore be abandoned. The same holds true of another derivation of the incest prohibition which counts many supporters, namely the assumption that primitive races very soon observed the dangers with which inbreeding threatened their race and that they therefore had decreed the incest prohibition with a conscious purpose. The objections to this attempted explanation crowd upon each other[183]. Not only must the prohibition of incest be older than all breeding of domestic animals from which men could derive experience of the effect of inbreeding upon the characteristics of the breed, but the harmful consequences of inbreeding are not established beyond all doubt even to-day and in man they can be shown only with difficulty. Besides, everything that we know about contemporaneous savages makes it very improbable that the thoughts of their far-removed ancestors should already have been occupied with preventing injury to their later descendants. It sounds almost ridiculous to attribute hygienic and eugenic motives such as have hardly yet found consideration in our culture, to these children of the race who lived without thought of the morrow[184].
And finally it must be pointed out that a prohibition against inbreeding as an element weakening to the race, which is imposed from practical hygienic motives, seems quite inadequate to explain the deep abhorrence which our society feels against incest. This dread of incest, as I have shown elsewhere[185], seems to be even more active and stronger among primitive races living to-day than among the civilized.