Let us examine this very curious theory. First: Mr. Morgan supposes early man to have made a discovery (the evils of the marriage of near kin) which evades modern physiological science. Modern science has not determined that the marriages of kinsfolk are pernicious. Is it credible that savages should discover a fact which puzzles science? It may be replied that modern care, nursing, and medical art save children of near marriages from results which were pernicious to the children of early man. Secondly: Mr. Morgan supposes that barbarous man (so notoriously reckless of the morrow as he is) not only made the discovery of the evils of interbreeding, but acted on it with promptitude and self-denial. Thirdly: Mr. Morgan seems to require, for the enforcement of the exogamous law, a _contrat social_. The larger communities meet, and divide themselves into smaller groups, within which wedlock is forbidden. This 'social pact' is like a return to the ideas of Rousseau. Fourthly: The hypothesis credits early men with knowledge and discrimination of near degrees of kin, which they might well possess if they lived in patriarchal families, but which, _ex hypothesi_, they could not possess. But it represents that they did not act on their knowledge. Instead of prohibiting marriage between parents and children, cousins, nephews and aunts, uncles and nieces, they prohibited marriage within the limit of the name of the kin. This is still the Hindoo rule, and, if the Romans really might not at one time marry within the _gens_, it was the Roman rule. Now observe, this rule fails to effect the very purpose for which _ex hypothesi_ it was instituted. Where the family name goes by the male side, marriages between cousins are permitted, as in India and China. These are the very marriages which some theorists now denounce as pernicious. But, if the family name goes by the female side, marriages between half-brothers and half-sisters are permitted, as in ancient Athens and among the Hebrews of Abraham's time. Once more, the exogamous prohibition excludes, in China, America, Africa, Australia, persons who are in no way akin (according to our ideas) from intermarriage. Thus Mr. Doolittle writes,[216] 'Males and females of the same surname will never intermarry in China. Cousins who have not the same ancestral surname may intermarry. Though the ancestors of persons of the same surname have not known each other for thousands of years, they may not intermarry.' The Hindoo _gotra_ rule produces the same effects.