declare at the same time a special vital force, a stability having a unified source, all this is nevertheless the consequence, or rather summation (Zusammenfassung), of a collection of separate and manifold fragmentary processes of a social nature. Our task, therefore, is to search these out.
The most general case in which the persistence of the group presents itself as a problem occurs in the fact that, in spite of the departure and the change of members, the group remains identical. We say that it is the same state, the same association, the same army, which now exists that existed so and so many decades or centuries ago. This, although no single member of the original organization remains. Here is one of the cases in which the temporal order of events presents a marked analogy with the spatial order. Out of individuals existing side by side, that is, apart from each other, a social unity is formed. The inevitable separation which space places between men is nevertheless overcome by the spiritual bond between them, so that there arises an appearance of unified interexistence. In like manner the temporal separation of individuals and of generations presents their union in our conceptions as a coherent, uninterrupted whole. In the case of persons spatially separated this unity is effected by the reciprocity maintained between them across the dividing distance. The unity of complex beings means nothing else than the cohesion of elements which is produced by the reciprocal exercise of forces. In the case of temporally separated persons, however, unity cannot be effected in this manner, because reciprocity is lacking. The earlier may influence the later, but the later cannot influence the earlier. Hence the persistence of the social unity in spite of shifting membership presents a peculiar problem which is not solved by explaining how the group came to exist at a given moment.
The first and most obvious element of the continuity of group unity is the continuance of the locality, of the place and soil on which the group lives. The state, still more the city, and also countless other associations, owe their unity first of all to the territory which constitutes the abiding substratum for all
