The author discusses a number of issues in the theory of legal sources. The first topic is whether sources should be conceived of as acts or texts. The alternatives are connected with two competing theories of legal interpretation (viz., the cognitive theory and the sceptical theory), which entail different concepts of legal rules and law‐making. The second topic is whether a “formal” or a “material” criterion of recognition of sources should be preferred. The third section is devoted to the analysis (...) of rules of change. Four theories of rules of change are discussed, and five kinds of such rules are distinguished. The fourth section concerns judicial law‐making, with special reference to the creation of new legal rules by constitutional courts. (shrink)