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...