  The so-called positivist thesis that all law depends for its existence, validity and obligatoriness on its social-fact source(s) is often accompanied, as in Raz’s “exclusive legal positivism” (Raz 1980, 212–24; Raz 1985), by the thesis that judges, as the “primary law-applying institutions,” have a duty (moral, if not also legal) to decide certain sorts of case (e.g., cases where the existing legal rule would by work injustice) by applying moral principles or rules which warrant amending or even abandoning part of the existing law.  “Inclusive” legal positivists temper this by holding that the judicial duty and authorization to depart from existing law by applying moral rules or principles is restricted to those classes of case where an existing social-fact sourced legal rule directs the court do so; the effect of such a directive, it is said, is to include within the legal system the moral rules or principles (if any) thus pointed to.