To this line of speculation it may perhaps further be objected that the question is not of the necessity of war to the race as a whole, but to the individual nation or major unit. The argument has been used that when a nation is obviously the repository of all the highest gifts and tendencies of civilization, the race must in the end benefit, if this nation, by force if necessary, imposes its will and its principles on as much of the world as it can. To the biologist the weakness of this proposition—apart from the plain impossibility of a nation attaining an objective estimate of the value of its own civilization—is that it embodies a course of action which tends to the spread of uniformity and to limit that variety of material which is the fundamental quality essential for progress. In certain cases of very gross discrepancy between the value of two civilizations, it is quite possible that the destruction of the simpler by the more elaborate does not result in any great {130} loss to the race through the suppression of valuable varieties. Even this admission is, however, open to debate, and it may well be doubted whether in some ways the wholesale extermination of “inferior” races has not denied to the species the perpetuation of lines of variation which might have been of great value. It seems remarkable that among gregarious animals other than man direct conflict between major units such as can lead to the suppression of the less powerful is an inconspicuous phenomenon. They are, it may be supposed, too busily engaged in maintaining themselves against external enemies to have any opportunities for fighting within the species. Man’s complete conquest of the grosser enemies of his race has allowed him leisure for turning his restless pugnacity—a quality no longer fully occupied upon his non-human environment—against his own species. When the major units of humanity were small the results of such conflict were not perhaps very serious to the race as a whole, except in prolonging the twilight stages of civilization. It can scarcely be questioned that the organization of a people for war tends to encourage unduly a type of individual who is abnormally insensitive to doubt, to curiosity, and to the development of original thought. With the enlargement of the unit and the accompanying increase in knowledge and resources, war becomes much more seriously expensive to the race. In the present war the immense size of the units engaged and their comparative equality in power have furnished a complete _reductio ad absurdum_ of the proposition that war in itself is a good thing even for the individual nation. It would seem, then, that in the original proposition the word “war” must be qualified to mean a war against a smaller and notably weaker adversary. The German Empire was founded on such wars. {131} The conception of the biological necessity of war may fairly be expected to demonstrate its validity in the fate of that