 Notwithstanding our understanding of social institutions as complex social forms, some theoretical accounts of institutions identify institutions with relatively simple social forms—especially conventions, social norms or rules. At one level this is merely a verbal dispute; contra our procedure here, such simpler forms could simply be termed “institutions”. However, at another level the dispute is not merely verbal, since what we are calling “institutions” would on such a view consist simply of sets of conventions, social norms or rules. Let us refer to such accounts as atomistic theories of institutions (Taylor 1985: Chapter 7). Schotter is a case in point (Schotter 1981) as is North (1990). The best known contemporary form of atomism is rational choice theory and it has been widely accepted in, indeed it is in part constitutive of, modern economics. The most influential philosophical theory within a broadly rational choice framework is David Lewis’ theory of conventions (Lewis 1969). According to Lewis, conventions are regularities in action that solve coordination problems confronted by individual agents.