It will probably be remarked that mutual aid, even though it may represent one of the factors of evolution, covers nevertheless one aspect only of human relations; that by the side of this current, powerful though it may be, there is, and always has been, the other current—­the self-assertion of the individual, not only in its efforts to attain personal or caste superiority, economical, political, and spiritual, but also in its much more important although less evident function of breaking through the bonds, always prone to become crystallized, which the tribe, the village community, the city, and the State impose upon the individual.  In other words, there is the self-assertion of the individual taken as a progressive element.

It is evident that no review of evolution can be complete, unless these two dominant currents are analyzed.  However, the self-assertion of the individual or of groups of individuals, their struggles for superiority, and the conflicts which resulted therefrom, have already been analyzed, described, and glorified from time immemorial.  In fact, up to the present time, this current alone has received attention from the epical poet, the annalist, the historian, and the sociologist.  History, such as it has hitherto been written, is almost entirely a description of the ways and means by which theocracy, military power, autocracy, and, later on, the richer classes’ rule have been promoted, established, and maintained.  The struggles between these forces make, in fact, the substance of history.  We may thus take the knowledge of the individual factor in human history as granted—­ even though there is full room for a new study of the subject on the lines just alluded to; while, on the other side, the mutual-aid factor has been hitherto totally lost sight of; it was simply denied, or even scoffed at, by the writers of the present and past generation.  It was therefore necessary to show, first of all, the immense part which this factor plays in the evolution of both the animal world and human societies.  Only after this has been fully recognized will it be possible to proceed to a comparison between the two factors.

To make even a rough estimate of their relative importance by any method more or less statistical, is evidently impossible.  One single war—­we all know—­may be productive of more evil, immediate and subsequent, than hundreds of years of the unchecked action of the mutual-aid principle may be productive of good.  But when we see that in the animal world, progressive development and mutual aid go hand in hand, while the inner struggle within the species is concomitant with retrogressive development; when we notice that with man, even success in struggle and war is proportionate to the development of mutual aid in each of the two conflicting nations, cities, parties, or tribes, and that in the process of evolution war itself (so far as it can go this way) has been made subservient to the ends of progress in mutual