Toward the end of his life Pareto wrote:
Driven by the desire to bring an indispensable complement to the studies ofpolitical economy and inspired by the example of the natural sciences, Idetermined to begin my Treatise, the sole purpose of which--I say sole and Iinsist upon the point--is to seek experimental reality, by the application tothe social sciences of the methods which have proved themselves in physics,in chemistry, in astronomy, in biology, and in other such sciences.
In this statement Pareto summarized his aim in writing his major sociologicalwork, The Treatise on General Sociology.
Pareto's ambition was to construct a system of sociology analogous in itsessential features to the generalized physico-chemical system which J. WillardGibbs formulated in his Thermodynamics. A physico-chemical system is anisolated aggregate of individual components such as water and alcohol. Thefactors characterizing the system are interdependent so that a change in onepart of the system leads to adjustive changes in its other parts. Pareto had asimilar conception of the social system, in which the "molecules" were individuals with interests, drives, and sentiments "analogous to the mixtures ofchemical compounds found in nature." Pareto's general sociology sets forththe concept of social system as a framework for analyzing mutually dependentvariations among a number of variables determining human conduct.
The treatise does not attempt to cover all the variables that are part of thesocial system. Only nonrational aspects of action are considered in any detail.Pareto's interest in sociology arose out of his previous concern with economicsand out of his realization that the variables with which economics operatedwere insufficient to account for much, if not most, of human behavior. The fieldof economics, he reasoned, especially in its modern form, had limited itself toa single aspect of human action: rational or logical action in pursuit of theacquisition of scarce resources. Pareto turned to sociology when he became con-vinced that human affairs were largely guided by nonlogical, nonrationalactions, which were excluded from consideration by the economists. For thisreason he attempts in his Treatise to understand the nonrational aspects ofhuman behavior, omitting almost completely the rational aspects which heconsidered to be treated adequately in his economic writings.
Pareto searched for a rational accounting of the prevalence of human ir-rationality. He did not intend to discard economic theory, in the manner ofVeblen, but rather to supplement its abstractions with sociological and social-psychological concepts that would help toward an understanding of thoseaspects of human conduct that had proved recalcitrant to economic analysis. Itis this analytical distinction between rational and nonrational elements ofaction and not a classification of concrete behavior that Pareto aimed at: "Itis not actions as we find them in the concrete that we are called upon toclassify, but the elements constituting them."
From Coser, 1977:387-388.