social differentiation. A major topic in the sociological classics, such as Simmel, Durkheim, and Weber. Often discussed in connection with developmental analyses (increasing differentiation), the explanation of modern individualism as a result of role differentiation, and the so-called rationalization of various spheres of life, such as the economy, religion, politics, etc. (see also: division of labor) Sociological systems theory argues that all forms of social differentiation are the result of system differentiation within the encompassing system of society. Luhmann: "Few forms of differentiation have been able to survive in long-term systems: above all, differentiation into similar units (segmentation), the differentiation of center/periphery, the differentiation conforming/deviant (official/unofficial, formal/informal), hierarchical differentiation, and functional differentiation. Apparently, the only forms of differentiation able to survive are those that can mobilize processes of deviation-amplification (positive feedback) to their own advantage and keep themselves from being leveled out again" (1995: 190)