The conditions of moral conduct are, then, so different as to forbid any attempt to compare the innate moral dispositions of primitive and civilised peoples; and all we can do, in order to arrive at an opinion, is to consider whether the conditions have been such as to favour the evolution of the moral disposition, the innate basis of the social tendencies, during the nation-making period. There can, I think, be no doubt that the principal condition of the evolution of the moral nature was group selection among primitive societies constantly at war with one another. In conflicts of that kind it must have been the solidarity of each group, resting upon the moral dispositions of individuals, the tendency of each individual to conform to the law and moral code of the society and to stand loyally by his leaders and comrades, which, more than anything else, determined success and survival in the struggle of the group for existence. At first, the nature of the code must have been of relatively small importance; the all important condition of survival of the group must have been the strict obedience to it on the part of the members of the group. This is not a deduction only from general principles. One may observe the effect of tribal conflict, on comparing, in various parts of the world, tribes that have long been subjected to its influence with closely allied tribes that have long led a peaceful existence[142]. At a later stage, as the traditional codes of morality became differentiated and more complex with the increasing complexity of societies, the nature of these codes must have acquired an increasing influence in determining group survival; but it must still have been subordinate in importance to the degree of development of the moral disposition; for a society with an inferior moral code, strictly conformed to by its members, would in the long run have better chances of survival than one with a higher code less strictly observed. Hence, the higher more difficult codes could only be attained by those peoples among whom the instinctive basis of social conduct had become highly evolved by a long process of group selection.