  This objection sometimes accompanies another: that Lewis overlooks the essentially normative character of conventions. The idea is that conventions concern not just how people actually behave but also how they should behave. In other words, conventions are regularities not (merely) de facto, but de jure. For instance, if there is a convention that people stand a certain distance from one another when conversing, then it seems natural to say that people should stand that distance when conversing. It is not obvious that Lewis can honor these intuitions, since his conceptual analysis does not mention normative notions. On this basis, Margaret Gilbert (1989) and Andrei Marmor (1996) conclude that Lewis has not provided sufficient conditions for a convention to prevail among some group.