Legal terms such as “owner”, “contract”, “possession”, “citizen” are “intermediaries” in the sense that they serve as vehicles of inference between statements of legal grounds, on one hand, and legal consequences, on the other. After introducing our approach to the representation of a normative system, we present a theory of “intervenients”, seen as a tool for analysing intermediaries. The paper is especially concerned with the subject-matter of open and closed intervenients as well as the related issue of negations of intervenients. Also, we introduce the idea of so-called gic-systems, where “gic” is an abbreviation of “ground-intervenient-consequence”.