In his classic work, The Passions and the Interests, Albert Hirschman describes the rise of the concept of interest in the seventeenth and eighteenth centuries. He shows how this concept, originally linked to statecraft and raison d'État theory, was so successful that it soon became a tool for interpreting not only the behavior of rulers, but also the totality of human conduct. “Once the idea of interest had appeared,” Hirschman remarks, “it became a real fad as well as a paradigm (à la Kuhn) and most of human action was suddenly explained by self-interest, sometimes to the point of tautology.”It is generally assumed that the birth of modern economic science, conventionally marked by the publication of The Wealth of Nations in 1776, was one of the most significant manifestations of the triumph of the “interest paradigm.” According to this view, self-interest provided the axiom upon which Adam Smith constructed his political economy. After the marginalist revolution in the second half of the nineteenth century, when economics became a highly formalized and mathematical discipline, self-interest was enshrined as the first principle that made all theoretical constructions possible. As F.Y. Edgeworth put it in 1881, “the first principle of Economics is that every agent is actuated only by self-interest.”