THE SCOPE OF SOCIOLOGY 245
say that every one of those named in our schedule is actually pres- ent, in some degree or other, in every stage or part or episode of the social process large enough to be observed. Analysis of a given section of experience involves use of these categories, then, not in any mechanical way, as though they were equally prominent and equally significant. It involves their use just as the different phases of reaction known to chemistry are employed in analyses of physical substances, i. e., in precisely the propor- tions in which they prove to have significance in the case in hand. We proceed to mention a series of concepts which are not of one and the same order of generality. Indeed, we have been obliged to employ most of them in the foregoing discus- sion. Although it would be desirable to place them more defi- nitely in hierarchical relations, we must be content merely to schedule them provisionally.
11. Contact. This concept has been emphasized earlier in this series. We have said that the most general and inclusive way in which to designate the subject-matter with which sociol- ogy must deal is by saying that it is concerned with all human contacts. One detail which cannot possibly be eliminated from the social condition, or from the idea of the social, is contact of one person with others. 1
12. Differentiation. We might recall Spencer's formula of evolution, viz.:
Evolution is an integration of matter and a concomitant dissipation of motion, during which the matter passes from an indefinite, incoherent homo- geneity, to a definite, coherent heterogeneity, and during which the relative motion undergoes a parallel transformation (First Principles, sec. 145).
Reduced to a single word, this formula would be that evolu- tion is differentiation. The rest of the formula merely character- izes certain features of this differentiation.
The social process, as a part of the world-process in general, is likewise a collection of differentiations. One way of telling the story of every individual life, or of universal history, or of anything intermediate, would be to narrate the differentiations
1 Vid. AMERICAN JOURNAL OF SOCIOLOGY, Vol. V, pp. 798, 799, and Vol. VI, pp. 328, 329.
