社会階層
Social stratification is the hierarchical arrangement of individuals into social classes, castes, and divisions within a society. Modern Western societies stratification traditionally relates to cultural and economic classes arranged in three main layers: upper class, middle class, and lower class, but each class may be further subdivided into smaller classes (e.g. occupational). Social stratification is interpreted in radically different ways within sociology. Proponents of structural functionalism suggest that, since the stratification of classes and castes is evident in all societies, hierarchy must be beneficial in stabilizing their existence. Conflict theorists, by contrast, critique the inaccessibility of resources and lack of social mobility in stratified societies.