may have had nothing to do with it such accidental and irrational sources of morals, and the resulting codes, are numberless.  But as in the process of organic evolution the various obscure physiological alterations which produce variations of type are all overruled and guided in a few directions of value to the species by the law of natural selection, so in the evolution of in all directions are subject to the law of the survival of the fittest.  It is really of comparatively little importance to discover how a given moral habit first arose; it may have arisen in a hundred different ways in a hundred different places; indeed, the precise origin of most of the cardinal virtues lies too far back in the mists of the past to be traced with assurance.  But the important truth to observe is not the particular details of their haphazard origin but the causes of their survival.  Overlaying the countless originating causes of moral ideals are two main preservation—­causes, two constant factors which retain certain of the innumerable impulses for one reason or other momentarily dominant.  These are of extreme significance for a comprehension of the function of morality in life.

(1) In the first place, a certain number of these blind, hit-or-miss experiments in conduct were, as we have seen, of use to individuals or the tribe in increasing their chances of survival in the ceaseless rivalry for life.  The inclemency’s of nature and the enmity of the beasts and other men kill more often the less moral than the more moral.  So that in general and in the long run those that developed the higher moral habits outlived the others and transmitted their morals to the future.  Even within historic times this same weeding-out process has been observable.  On the whole, the races and the individuals with the more advanced moral standards survive, while those of lower standards perish.  This law accounts, for instance, in some measure probably for the relatively greater increase of whites than of Negroes in the United States, in spite of the higher birth rate of the latter.  Other causes are, to be sure, also at work in this competition for life; for one thing, the long period of intercommunication between European races has largely weeded out the stocks most liable to certain diseases, while the antecedent isolation of savage tribes, with no such elimination at work, allows them to fall victims in greater numbers to European diseases when mutual contact is established.  But the degree of the moralization of a people has been certainly one of the criteria of survival; and thus by a purely mechanical elimination mankind has grown more and more moral.  It hardly needs to be added that the conscious selection of codes that tend to preserve life is a factor of growing importance in insuring movement in this same direction.  Altogether, moral progress consists primarily in an increasing adaptation of codes to the preservation of life.