What now are the lessons of social evolution and what guidance does science give for human endeavor? Although it may seem that the biologist leaves his field when he considers these questions, his duty would be unfulfilled if he neglected an opportunity to give his results their highest utility through their use for the betterment of human life.
The first lesson is that the history of human social organization is far from unique, and that it is identical with the process by which insect communities and cell-aggregates have evolved; in a word, the laws of biological association are uniform throughout the entire organic scale. In some respects evolution in mankind has yet to equal the heights attained by some insects, inasmuch as no human society has accomplished so rigid a specialization of its members that a given individual is foreordained by its inherited structure to be a particular kind of worker and nothing else. Furthermore, evolution in human society is still far short of a state where some and some only are reproductive members of the group while the others are necessarily sterile; social insects with stable colonies are so organized that the queens and drones are solely reproductive while the workers are destined to care for the material wants of the colony. It is true that the birth-rate is by no means the same in all classes of society, but the social and other adventitious restrictions that bring this about are not on the same plane with the hereditary determining factors which operate among insects. Therefore the scale of human communities proves to be only a part of the wider range of organic associations in general--a part which can be definitely placed in such a wider scheme and so become more intelligible in itself.
In all departments of social evolution, progress is made by the twofold process of combination and differentiation. We have dealt with detailed instances, and now it is profitable to treat the process in a larger way, with a view toward the possibilities of the future. The Thirteen Colonies, somewhat similar in their earlier economic activities, united for mutual support much as wolves combine to form a pack. Later, as circumstances directed, they differentiated into farming or manufacturing or commercial organs of the body politic, each to some degree freeing itself of the functions undertaken by others, and becoming thereby more dependent than before upon those that specialized in different ways. As in the history of the insects in a growing wasp community and of savages evolving into barbarians, the original condition of relative independence passed into a state of interdependence and cooperation. In like manner, if nature remains the same, as there is every reason to believe it will, nations now separate will unite to make more complex combinations that will be veritable empires of world-wide scope. Countries on opposite sides of an ocean are now more closely connected by lines of communication and means of travel than were the Carolinas and New England a century ago. Diplomatic activities give many signs of a growing appreciation of the value of reciprocal agreements for mutual advantage, and the Hague Conference is a concrete manifestation of a continuing process of social evolution that finds its beginnings and its interpretation far below human history in lower organic nature.