Such a form coexists neither with an actual ungraded equality of individuals throughout the group, nor if the group consists of an upper and a lower class separated from each other by no intervening medium. The middle class, in fact, adds an entirely new sociological element. It is not only a third in addition to the two. It does not merely have somewhat the same, that is, quantitative, relation to each of these that they have to each other. The new element is rather that this third stratum itself has an upper and a lower boundary, that upon these boundaries an exchange with the other two strata is constantly taking place, and that through this continual fluctuation effacement of boundaries and continual transitions are produced.
An actual continuity of social life does not arise from the fact that individuals are built into positions one above another, with never so slight gradations. This would still produce discontinuous structure. Continuity exists only when single individuals circulate through higher and lower positions. Only thus is the separateness of strata changed over into an actually uninterrupted structure. In the fortune of the individuals the upper and the lower situation must first meet, in order that the sociological picture may show an actual mediation between the upper and the lower. Precisely this, and not a simple intermediate position, is secured by a middle class. It requires little reflection to discern that this closeness of gradation must characterize also the grades within the middle class. The continuity of stations with reference to repute, possessions, activity, culture, etc., rests not merely in the minuteness of the differences which are coördinated in an objective scale, but rather in the frequency of the change which leads one and the same person through a number of such situations, and thus produces at the same time perpetual and varying personal unions of objectively different situations. Under these circumstances the social aspect, as a whole, will be that of elasticity. The dominant middle class affords the medium of easy interchangeability of the elements, so that the self-preservation of the group throughout the change of external or internal circumstances and assaults is accomplished not so much because of fixity and rigidity in the
