From a philosophical point of view, conventions are expressions of collective intentionality, to the effect that certain social phenomena are accepted or recognized as having legal significance, or that there exist a set of mutual expectations and cooperative dispositions to the said effect in the community. Legal conventions are institutional facts, defined by a set of constitutive rules. According to John R. Searle, the general form of an institutional fact is: "X counts as Y in context C". Legal conventions may be formal and institutional or informal and customary in kind. Still, mere acceptance or recognition of a social phenomenon as legal by the members of the community is not enough to guarantee its legally qualified status, if the institutional prerequisites for the judgment are not present, as well. Historically, the roots of legal conventionalism can be traced back to the historical school of law, founded by Friedrich Carl von Savigny in Germany in the nineteenth century. According to von Savigny, the origins of the legal system were anchored in the organically evolving spirit of the nation (Volksgeist). As a consequence, the common legal consciousness or shared legal convictions in the community would guide the "organic" path of the law, as found expression in the well-settled practices and usages of customary law in the traditional legal systems and in the lawyers' law (Juristenrecht) or the law professors' law (Professorenrecht) in more sophisticated legal systems. As to legal argumentation, the results produced by legal conventionalism do not to a significant degree deviate from those obtained by analytical legal positivism and the new rhetoric, as illustrated by the results obtained by the research group Bielefelder Kreis.