598 THE AMERICAN JOURNAL OF SOCIOLOGY
psychology necessitates, yet it is not too early to attempt to sketch in outline that view ; and such is the purpose of this paper.
Put in a sentence, the psychological view of society is, that it is a mass of interactions, of interstimulations and responses, between individuals, not haphazard, but regular, co-ordinated, and controlled, working, for the most part, toward definite ends, and making groups true functional unities, ruled by habit largely, but, like all organic unities, undergoing adaptive changes which are themselves regular and which, moreover, give rise to the most important socio-psychical phenomena. Analyzed, this statement means that the essence of society is mental interaction, i. e., inter- stimulation and response; and that the fundamental fact with which the sociologist has to deal is this interaction, this inter- stimulation and response, between individuals. It is this inter- stimulation and response which makes up all social phenomena and which is, therefore, the subject-matter of all the social sci- ences, and particularly of sociology. The significant thing for the sociologist, however, is not that these interactions between individuals exist, but that they are regular; not haphazard, but co-ordinated and controlled. Without this regularity in the forms of interaction between individuals, social science in general would be impossible, for the object of all scientific study of society is to discover regularity in social activity, that is, in the forms of interstimulation and response among individuals.
This regularity and co-ordination in mental interaction, inter- stimulation, and response, which brings to unity of aim the activities of individuals, may be called the social co-ordination, just as the bringing to a unity of aim of physical and psychical processes in the body is called a co-ordination. This co-ordination of individuals in activity is, of course, what makes group action possible. It creates the unity of the group; and the co-ordina- tions that persist, become habitual, form the very substance of permanent social organization, and, as has already been said, it is the changes in these social co-ordinations, the breaking-down of old ones and the building-up of new ones, which give rise to the most important phenomena of collective psychical life. We are justified in concluding, therefore, that the most important.
