In legal theory, a well-known idea is that an intermediate concept like "ownership" joins a set of legal consequences to a set of legal grounds. In our paper we attempt to make the idea of a joining between grounds and consequences more precise by using an algebraic representation of normative systems earlier developed by the authors. In the first main part the idea of intermediate concepts is presented and earlier discussions of the subjects are outlined. Subsequently, in the second main part, we introduce a more rigorous framework and develop the formal theory. In the third part the formal framework is applied to examples and some remarks on a methodology of intermediate concepts are given.