The evolution of organic life goes on in geometrical progression: cells combine, and form organs; organs combine, and form organisms; organisms combine, and form organizations. Society is an organization. Society is the fourth power of the cell. It is composed of individual animals of genus homo, living in organic relation. The course of social evolution is the gradual establishment of organic relation between individuals, and this organic relation rests on purely economic grounds. In the simplest combination of primordial cells the force that drew and held them together was that of economic necessity. It profited them to live in combination. Those that did so survived, and those that did not perished. So with the appearance of the most elaborate organisms: it profited them to become a complex bundle of members and organs in indivisible relation. A creature so constructed survived, where the same amount of living matter unorganized would have perished. And so it is, literally and exactly, in a complex society, with all its elaborate specialization of individuals in arts and crafts, trades and professions. A society so constructed survives, where the same number of living beings, unorganized, would perish. The specialization of labor and exchange of product in a social body is identical in its nature with the specialization and exchange of function in an individual body. This process, on orderly lines of evolution, involves the gradual subordination of individual effort for individual good to the collective effort for the collective good,—not from any so-called “altruism,” but from the economic necessities of the case. It is as natural, as “selfish,” for society so to live, the individual citizens working together for the social good, as for one’s own body to live by the hands and feet, teeth and eyes, heart and lungs, working together for the individual good. Social evolution tends to an increasing specialization in structure and function, and to an increasing interdependence of the component parts, with a correlative decrease through disuse of the once valuable process of individual struggle for success; and this is based absolutely on the advantage to the individual as well as to the social body.