Equilibrio, disequilibrio e tempo in Walras

Walras’s theory of general economic equilibrium goes through many changes over the twenty-six years elapsing from the publication of Walras’s first significant theoretical contribution in 1874 and the appearance, in 1900, of the fourth edition of his masterpiece, the Eléments d’économie politique pure. This paper reconstructs the main steps characterizing the twisted evolution of Walras’s ideas concerning equilibrium, disequilibrium, and time in economics. Early in his scientific career, Walras perceives, albeit confusedly, the existence of theoretical, analytical, and epistemological difficulties undermining his analysis of the tâtonnement processes associated with his equilibrium models of exchange, production, and capital formation; yet he refrains from facing such issues squarely for fear that this would compel him to give up all realistic justification in support of his theory. Concerning the exchange model, under the pressure of external criticism, Walras soon enough yields to the logical requirements of the analysis, by explicitly endorsing, since 1885, the so-called “no-trade-out-of-equilibrium” assumption, an assumption which forces him to interpret the tâtonnement process in exchange as a purely virtual equilibration process in “logical” time, supporting an “instantaneous” equilibrium notion. Concerning the production and capital formation models, however, Walras strenuously strives to preserve the pseudo-realistic assumptions permeating his original view of the tâtonnement construct: up to the third edition of the Eléments (1896), in fact, Walras keeps to the idea that the tâtonnement process in production should be viewed as an actual equilibration process in “real” time, supporting a “stationary” equilibrium notion. Yet, due to his eventual realization of the logical contradictions engendered by such interpretation of both the tâtonnement process and the associated equilibrium notion, hardly – if at all – compensated by a few dubious gains in terms of descriptive realism, in the fourth edition of the Eléments Walras eventually resolves to give up all pseudo-realistic pretence concerning the equilibration process: in 1900, in fact, he adopts a novel, openly unrealistic assumption, the so-called “hypothèse des bons”, to the effect of turning all tâtonnement processes, including those concerning production, into virtual processes in “logical” time, supporting a generalized notion of “instantaneous” equilibrium of the “temporary” type JEL classification codes: B13, B21, B31, B41, C62, D51