Be it noted, to avoid misapprehension, that I have here been using the community to denote the single aggregate unit which from the beginning has played such an important part biologically in human evolution, not merely as denoting the sum of individuals considered separately. Thus biology gives a definite answer to this question too. Pure individualism is condemned, and so is what we may call ant-and-bee socialism. Some form of the “dual day,” to use a current phrase, or at least of the “dual life,” is the method which seems to be in accord with the enduring principles of biology, although the precise details are not and cannot be the biologist’s concern, and particular lives, such as that of the creative artist, who moves on a different plane of reality, escape his analysis. I have reserved to the close that biological principle which has been most often and most seriously misapplied in sociology and politics--the struggle for existence. Never was the proverb about the Devil’s quoting Scripture better exemplified than in this matter. This fundamental idea of Darwin’s has been used as justification for three totally different and indeed incompatible political doctrines. In England, it has served chiefly to bolster up _laissez-faire_ individualism and free competition. In Germany in the years immediately succeeding the publication of the _Origin of Species_, it was seized upon by the Socialists as implying equal opportunity for all as against feudalism or hereditary aristocracy. Later in the same country (and to a certain extent elsewhere) it was abundantly employed as a theoretical support for militarism. As a matter of fact, the use of it as sole principle governing the interrelation of biological units is wholly unjustified. As has been shown by a number of writers, among whom may especially be mentioned Darwin himself, Ritchie in his _Darwinism and Politics_, and Kropotkin in his _Mutual Aid_, the struggle for existence is only _one_ of two possibilities in this relationship: the other is that of co-operation, of mutual aid, which is especially well marked in the building up of higher-grade units from a multiplicity of smaller lower-grade ones. Two of the most important steps in the whole evolutionary process have been based on the co-operation of units--the origin of multicellular from unicellular organisms, and the development of true man, with his social life, from his pre-human ancestor. It is also prominent in the lives of many species of the highest groups--insects, mammals, and birds: witness the ants and bees, the rook, the wild dog, the elephant, the baboon. In fact, once the bodily specialization of units has reached a certain pitch, progress, as we have seen, is only possible through mental development, and this in the great majority of cases brings about aggregation into some sort of community, held together by mental bonds.