By the early Fathers of the Church this idea of collective responsibility, embodied in the doctrine of the imputation of the guilt of the transgression of the first man Adam to all his descendants to the end of the world, was given a prominent place in Christian theology and has been a great force in molding the morality of the Western world. Again, we find this idea of group morality embodied in the war ethics of the modern nations, which, regarded from one point of view, is largely group ethics, that is to say, the survival in the domain of international relations of ethical ideas that had their birth on the low intellectual and moral levels of barbarism. As we follow the upward trend of the lines of the moral evolution of the race we shall hear louder and louder protests against this notion of communal responsibility, especially when this form of human morality has been transferred to the heavens and made a fundamental principle of the divine government. [Sidenote: The duty of revenge; the blood feud] In primitive society if a man slay a kinsman, he is punished by outlawry, that is, by expulsion from the family or clan.[44] The story of Cain, the first murderer of a kinsman in Hebrew legend, is typical.[45] If, however, a member of a clan is slain by an outsider, it is the duty of the nearest kinsman of the person killed, or of the collective body of his kinsfolk, to kill in revenge the slayer or some relative of his.[46] To ignore this obligation or to forgive the slayer of one’s kinsman is regarded as base and cowardly. As, through the advance of society, the ties of the clan become relaxed and this group becomes more and more perfectly merged with the larger group of the tribe or state of which it has become a part, and justice comes to be administered by the tribal head or by regular tribunals, then blood revenge on the part of the kinsmen of the slain gradually ceases to be a duty and private vengeance becomes a crime. But this is a slow evolution, and within societies far advanced in civilization we often find belated groups still following with good conscience the ancient custom of blood revenge. The vendetta in Italy and the feud in some sections of our Southern states[47] are survivals or degenerate forms of this primitive virtue. [Sidenote: The _Lex talionis_]