The research program called « Economics of Conventions » aims at revisiting the century- long separation, within mainstream economics, between the issues of coordination, rationality and ethics. In the realistic world of bounded rationality, the rules are a fundamental means of coordination. An important subset of rules consists in conventions (of which a restrictive definition was provided by the american philosopher David Lewis), but every kind of rule is generally uncomplete, so that it is necessary to resort to collective representations associated with their expected correct application. Since the agreement upon these representations can be viewed as a conventional phenomenon, conventions in economics become quite comprehensive. From a microeconomic point of view, wages are the results of rules. Does that mean that they are conventional rules ? Many authors have exploited the idea that the amount of wages was determined by a convention. This idea is confronted by insuperable obstacles, suggesting the relation with conventions should be looked for at another level. Any firm, whatever its model of management, rests on a quasi social-contract, linking the dynamics of wages and labour productivity : the wage rules, empirically very diverse, are interpreted through this conventional pact. We define three pure models of business firms (merchant, industial, domestic), or three « dynamic conventional equilibria » . They correspond to three profiles of the employment/wage schedule, decreasing, flat, increasing. From a macroeconomic point of view, the diversity of the employment/wage schedule, at the level of firms, explains the fact that the trend of real wages makes very weak forecasts of the trend of employment -unlike the trend of effective demand. The predictive superiority of this last index comes from the betting system on which all the firms are built, together with the identity which binds the change of the macroeconomic variables. The concept of dynamic macro-equilibrium appropriate to the « Economics of Conventions » splits in two pieces : in the short run, the constancy of unemployment and interest rates, whatever their value, appeal to the neo-keynesian thesis of possible multiple equilibria ; in the long run, we define a « rule-equilibrium », when applying the received rules for modifying transaction confines the sequence of the « short-run dynamic macro-equilibria » within a « corridor », which does not erode the collective agreement upon « normal conjoncture », especially with respect to the goal of full employment.
La synthèse néoclassique a proposé une interprétation de la Théorie Générale en termes de rigidités nominales qui a largement influencé l'École keynésienne et orienté ses travaux sur la recherche de fondements micro-économiques à la rigidité des prix. Cette voie de recherche a conduit à une triple impasse : technique, méthodologique et empirique. On étudie alors comment le programme de recherche de l'École keynésienne s'est restructuré en développant des concepts nouveaux conduisant à relativiser l'importance du lien emploi-salaire et à repenser la nature et les objectifs de l'intervention de l'État
