Bio: (1941-2001) Danish-American sociologist. Aage Sørensen was born in Denmark, but studied and had his professional career in the United States. He received his doctorate from Johns Hopkins University and taught at the University of Wisconsin and Harvard. He predominantly studied economic inequalities and classes. Sørensen developed his theoretical approach to classes. He sees classes are structural positions within social relations in the market, especially the labor market. Class locations are related to specific interests, and these interests are antagonistic. These interests can influence the formation of class consciousness, and that consciousness can lead to action, which can take the form of class struggle. His theory of classes studies changes in social structure, so it can be used to produce a theory of history. In his theory, classes are not arranged hierarchically, as sets of ever higher positions.

Sørensen believes that any theory that seeks to explain the differences in income of different classes must meet three conditions: 1) it has to see classes as sets of "empty locations" that are filled by individuals; 2) it has to explain differences in earnings by members of different classes; 3) its theoretical predictions have to be able to be empirically tested through measurable variables. Sørensen emphasizes that real class privileges stem from the structural effects of classes on inequality. Structural effects of class inequality affect the change of social structure, because, privileges or deprivations associated with class location, create antagonistic interests. Antagonistic interests, because of these advantages, affect the emergence of conflict and change the social structure.

Sørensen introduces the concept of "rent" as the basis for understanding classes. He studies how the structural effects of rents affect the formation of classes and class interests. Rent, in Sørensen's theory, is a source of extra income, and it is a consequence of differences in the distribution of certain resources in society. Resources that represent the source of rent are: ownership of capital and land, possession of technology, possession of specific skills, monopoly position, etc. The existence of rent forms the basis of exploitation, and classes are formed as structural locations (occupied by individuals), which are exploited or exploit others through rent.

The exact number of basic class positions in some societies will depend on the specific social, economic, and historical circumstances in that society. If these structural positions are more permanent and greatly affect the life chances of individuals, then class interests will be formed, which can create class consciousness and class struggle. Guarding and seeking rent are the basic forms of class struggle. Sørensen sees the solution to the problem of exploitation in the elimination of rent in a perfect market system in which there would be essential equality of opportunity. Such a society would, in essence, be a classless society, because the distribution of wealth would be such to create equality of all structural positions throughout the life of an individual.

Main works

,,On the Usefulness of Class Analysis in Research on Social Mobility and Socioeconomic Inequality‟, in Acta Sociologica (1991);

,,The Structural Basis of Social Inequality‟, in The American Journal of Sociology (1996);

,,Toward a Sounder Basis for Class Analysis‟, in The American Journal of Sociology (2000).