We need not speculate about the thought that influenced Parsons, either in his assumptions about human nature, society, and science or in his theoretical orientation. He identified them early (1937: v). They included three Europeans who played crucial roles in the early development of sociology: Emile Durkheim, Vilfredo Pareto, and Max Weber. The remaining figure was British economist Alfred Marshall.

From Pareto and Durkheim came the inspiration for Parsons' theoretical structure that presents an overarching and unified social system. Society thus becomes a holistic entity driven toward an equilibrium of parts. Societal elements are interdependent and adjustive, meeting always the needs of the system. From Weber, Parsons drew the concept of social action to develop his own framework for explaining how actors come to interpret their situation. However, it was Pareto's conception of the mutual interpenetration of human action and other systemic elements that most clearly informed Parsons' efforts to construct a macrosociological theory of systems in the positivist tradition.

Finally, Parsons used the work of Marshall to develop his model of the demand economy and the necessary equilibrium of the free market. He was then to relate the economic system to the solidarity of the broader societal order. In Parsonian theory, the free economic system adds to the cohesion of society by means of contracts, the definition of property rights, and the establishment of relationships between employers and employees (Perdue, 1986, pp. 114-115).