Every advance in strength, speed, agility, or sagacity in creatures of the one class, has necessitated a corresponding advance in creatures of the other class; and without never-ending efforts to catch and to escape, with loss of life as the penalty for failure, the progress of neither could have been achieved.
Mark now, however, that while this merciless discipline of nature, "red in tooth and claw," has been essential to the evolution of sentient life, its persistence through all time with all creatures must not be inferred. The high organization evolved by and for this universal conflict is not necessarily for ever employed to like ends: the resulting power and intelligence admit of being far otherwise employed. Not for offense and defense only are the inherited structures useful, but for various other purposes; and these various other purposes may finally become the exclusive purposes. The myriads of years of warfare which have developed the powers of all lower types of creatures have bequeathed to the highest type of creature the powers now used by him for countless objects besides those of killing and avoiding being killed. His teeth and nails are but little employed in fight; and his mind is not ordinarily occupied in devising ways of destroying other creatures, or guarding himself from injury by them.
Similarly with social organisms. We must recognize the truth that the struggle for existence between societies has been instrumental to their evolution. Neither the consolidation and reconsolidation of small social groups into large ones, nor the organization of such compound and doubly compound groups, nor the concomitant developments of all those aids to a wider and higher life which civilization has brought, would have been possible without intertribal and international conflicts. Social coöperation is initiated by joint defense and offense; and from the coöperation thus initiated all kinds of coöperations have arisen. Inconceivable as have been the horrors caused by this universal antagonism which, beginning with the chronic hostilities of small hordes tens of thousands of years ago, has ended in the occasional vast battles of immense nations, we must nevertheless admit that without them the world would still have been inhabited only by men of feeble types, sheltering in caves and living on wild food.
But now observe that the intersocial struggle for existence which has been indispensable in evolving societies will not necessarily play in the future a part like that which it has played in the past. Recognizing our indebtedness to war for forming great communities and developing their structures, we may yet infer that the acquired powers, available for other activities, will lose their original activities. While conceding that without these perpetual bloody strifes civilized societies could not have arisen, and that an adapted form of human nature, fierce as well as intelligent, was a needful concomitant, we may at the same time hold that, such societies having been produced, the brutality of nature in their units which was necessitated by the process, ceasing