The paper focuses on the issue of compatibility of social institution and convention. At first, it introduces the modest account of conventionality building on five distinctive features – interdependence, arbitrariness, mind-independence, spontaneity, and normative-neutrality – which constitute conventional behaviour, then it presents the two major theories of social institutions that explain them in terms of rules, or equilibria. The argument is that conventions cover a wide-ranging area and cannot be identified with the category of institutions because it would be too (...) restrictive and contradictory to the initial modest account. (shrink)