inaccessibility of resources and lack of social mobility found in stratified societies. Many sociological theorists have criticized the fact that the working classes are often unlikely to advance socioeconomically while the wealthy tend to hold political power which they use to exploit the proletariat (laboring class). Talcott Parsons, an American sociologist, asserted that stability and social order are regulated, in part, by universal values. Such values are not identical with "consensus" but can indeed be an impetus for social conflict, as has been the case multiple times through history. Parsons never claimed that universal values, in and by themselves, "satisfied" the functional prerequisites of a society. Indeed, the constitution of society represents a much more complicated codification of emerging historical factors. Theorists such as Ralf Dahrendorf alternately note the tendency toward an enlarged middle-class in modern Western societies due to the necessity of an educated workforce in technological economies. Various social and political perspectives concerning globalization, such as dependency theory, suggest that these effects are due to changes in the status of workers to the third world. Four underlying principles Four principles are posited to underlie social stratification. First, social stratification is socially defined as a property of a society rather than individuals in that society. Second, social stratification is reproduced from generation to generation. Third, social stratification is universal (found in every society) but variable (differs across time and place). Fourth, social stratification involves not just quantitative inequality but qualitative beliefs and attitudes about social status. Complexity Although stratification is not limited to complex societies, all complex societies exhibit features of stratification. In any complex society, the total stock of valued goods is distributed unequally, wherein the most privileged individuals and families enjoy a disproportionate share of income, power, and other valued social resources. The term "stratification system" is sometimes used to refer to the complex social relationships and social structures that generate these observed inequalities. The key components of such systems are: (a) social-institutional processes that define certain types of goods as valuable and desirable, (b) the rules of allocation that distribute goods and resources across various positions in the division of labor (e.g., physician, farmer, ‘housewife’), and (c) the social mobility processes that link individuals to positions and thereby generate unequal control over valued resources. Social mobility Social mobility is the movement of individuals, social groups or categories of people between the layers or within a stratification