Many writers whom we do not need to review in great detail have contributed to the objections to the biological principle as an explanation of war. Trotter (82) examines the doctrine that war is a biological necessity, and says that there is no parallel in biology for progress being accomplished as a result of a racial impoverishment so extreme as is caused by war, that among gregarious animals other than man direct conflict between major groups such as can lead to the suppression of the less powerful is an inconspicuous phenomenon, and that there is very little fighting within species, for species have usually been too busy fighting their external enemies. Mitchell (10) says that war is not an aspect of the natural struggle for existence, among individuals; that there is nothing in Darwinism that explains or justifies wars; that the argument from race is worthless since there are no pure races. M'Cabe (76) maintains that war is not a struggle between inferior and superior national types. Dide (20) also discusses the question of differences of race as causes of war, and the use that has been made of this dogma. Chapman (39) says that no race question is involved in the present war as has been supposed. There is no conflict of economic forces, no nations compelled to seek expansion. Precisely how warfare originated (assuming that it arose in one way) we shall probably never know, since we cannot now reconstruct the actual history of man. We think of men as living at first in groups containing a few individuals, and presumably for a long time these small and isolated groups of men prevailed as the type of human society. We can already detect the elements of conflict in these groups, but whether warfare in the sense of deadly conflict originated there we cannot know; or whether it was only in the experience of men as large migrating hordes which had been formed by the amalgamation of smaller groups under the influence of hunger or climatic change, that warfare in any real sense came into the world. We do not know to what extent the small groups of men we find in conditions of savagery now represent primitive conditions. Fortunately, however, some of these problems of origin are of but little practical importance and their interest is chiefly antiquarian or historical.