The foregoing classification is not quite adequate nor wholly logical. The first three classes are more closely related to one another than they are to the last two, i.e., the so-called "accommodation" and "conflict" groups. The distinction is far-reaching, but its general character is indicated by the fact that the family, language, and local groups are, or were originally, what are known as primary groups, that is, groups organized on intimate, face-to-face relations. The conflict and accommodation groups represent divisions which may, to be sure, have arisen within the primary group, but which have usually arisen historically by the imposition of one primary group upon another. Every state in history was or is a _state of classes_, a polity of superior and inferior social groups, based upon distinctions either of rank or of property. This phenomenon must, then, be called the "State."[50] It is the existence at any rate of conflict and accommodation within the limits of a larger group which distinguishes it from groups based on primary relations, and gives it eventually the character described as "secondary." When a language group becomes militant and self-conscious, it assumes the character of a nationality. It is perhaps true, also, that the family which is large enough and independent enough to be self-conscious, by that fact assumes the character of a clan. Important in this connection is the fact that a group in becoming group-conscious changes its character. External conflict has invariably reacted powerfully upon the internal organization of social groups. Group self-consciousness seems to be a common characteristic of conflict and accommodation groups and distinguishes them from the more elementary forms of society represented by the family and the local community. 3. _Organization and structure of social groups._--Having a general scheme for the classification of social groups, it is in order to discover methods of analysis that are applicable to the study of all types of groups, from the family to the sect. Such a scheme of analysis should reveal not only the organization and structure of typical groups, but it should indicate the relation of this organization and structure to those social problems that are actual and generally recognized. The sort of facts which are now generally recognized as important in the study, not merely of society, but the problems of society are: a) Statistics: numbers, local distribution, mobility, incidence of births, deaths, disease, and crime. b) Institutions: local distribution, classification (i.e., (i) industrial, (ii) religious, (iii) political, (iv) educational, (v) welfare and mutual aid), communal organization. c) Heritages: the customs and traditions transmitted by the group, particularly in relation to religion, recreation and leisure time, and social control (politics). d) Organization of public opinion: parties, sects, cliques, and the press.