In spite of this denotative variance, however, underlying the discussion and use of the concept are common assumptions which are also shared by my definition. 2 First, class membership is not biologically determined, but is a form of social stratification based on laws, esteem, wealth, or power. Estates or castes may comprise types of class stratification, or classes may be defined by different status-ranks. Second, in general a difference in class is a difference in wealth, power, or esteem. All definitions do not assume an identity between class and rank, but all assume a correlation.
Class is a division in privileges.
Third, class is a dividing line between different kinds of behavior. What these behaviors are depends on the actual definition, but nonetheless all definitions assume that different classes can be separated empirically according to different patterns of behavior, such as intermarriages, social mixing, organizational memberships, travel, etiquette, and mannerisms. Fourth, all definitions assume that class membership has continuity. There is disagreement as to whether membership may be frozen, as for castes, but in no case are classes considered ad hoc or momentary aggregations, like a crowd. There may be a circulation of members between classes, but it is not so rapid as to homogenize their distinctive behaviors nor to change in a generation more than a small proportion of class membership.