240 THE AMERICA* JOURNAL OF SOCIOLOGY
and what social dynamics, and how these two primary depart- ments are to be marked off, distinguished and recognized. First of all it must be insisted that the terms are not used merely as smooth expressions that have a scientific sound, or as remote analogies to those of exact science, but for what they actually mean, and in precisely the same sense that they have in pure mechanics or in solar astronomy. By this is not meant that the phenomena of society are capable of reduction to exact mathe- matical tests in any such degree as can be done in astronomy and physics, but merely, as already pointed out, that the highest generalizations in sociology are subject to theoretical treatment as exact as the observed phenomena of the planets or of falling bodies. It may be regarded as a sort of pure sociology, and it certainly has a far better sanction than either the "pure morals" of Kant or the "absolute ethics" of Spencer.
Beginning, then, with social statics, it must be defined as : social forces in equilibrium. We must then seek for cases in which social forces are in a state of equilibrium, or approximately so ; for in so complex a field as society nothing absolute is to be expected when actual phenomena are under investigation. A moment's inspection shows that the social forces do not always and universally result in movement, that they conflict and collide with one another, that they choke one another, and are constantly tending to bring about a cessation of motion, i. e., they tend towards the state of equilibrium. The larger masses (social groups) are first brought to rest, but within these masses there goes on a sort of molecular activity by which free paths are opened for the performance of minor operations. The general result is what may be called a social structure. In a wider sense these social structures may be called institutions. As examples of social structures proper may be mentioned the family, the clan, the tribe, the state, the church, and each and all of the innumerable voluntary associations of society. As examples of institutions maybe instanced marriage, government, language, customs, ethical and conventional codes, religion, art, and even literature and science.
