Georg Simmel
Simmel discussed social and cultural phenomena in terms of "forms" and "contents" with a transient relationship, wherein form becomes content, and vice versa dependent on context. In this sense, Simmel was a forerunner to structuralist styles of reasoning in the social sciences.
Through "The Metropolis and Mental Life" Simmel was a precursor of urban sociology, symbolic interactionism, and social network analysis. An acquaintance of Max Weber, Simmel wrote on the topic of personal character in a manner reminiscent of the sociological ideal type. He broadly rejected academic standards, however, philosophically covering topics such as emotion and romantic love. Both Simmel and Weber's nonpositivist theory informed the eclectic critical theory of the Frankfurt School. Provided by Wikipedia