Parsons developed a general theory for the study of society called action theory, based on the methodological principle of voluntarism and the epistemological principle of analytical realism. The theory attempted to establish a balance between two major methodological traditions, that of the utilitarian-positivist tradition on the one hand and the hermeneutic-idealistic tradition on the other. For Parsons, voluntarism established a third alternative between these two. More than a theory of society, Parsons presented a theory of social evolution and a concrete interpretation of the "drives" and directions of world history.
Parsons analyzed the work of Émile Durkheim and Vilfredo Pareto and evaluated their contributions within the light of the paradigm of voluntaristic action. Parsons was also largely responsible for introducing and interpreting Max Weber's work to American audiences. Although he was generally considered a major structuralist functionalist scholar, in an article late in life, Parsons explicitly wrote that the term "functional" or "structural functionalist" were inappropriate ways to describe the character of his theory. For Parsons "structural functionalism" was the term of a particular stage in the methodological development of the social science; it was never a name for any specific school or specific direction. "Functionalism" itself was a universal method and again not a name for any specific school. In the same way, the concept "grand theory" is a derogative term, which Parsons himself never used.