This paper explores what is apparently a non-topic for Luhmann. Luhmann is preoccupied with decision-making rather than with judgment. The paper argues that Luhmann, attempting to find a way out of the dilemma between the fundamentalism of positivistic legal theory and the relativism of anti-foundationalist post-modern thinking, presents the epistemological–ethical doublet of a “self-binding” of the law. In this bootstrapping manoeuvre decision plays the central part. The paper begins by examining judgment in its relation to decision as considered by non-system-theoretical thinking. Against that background it unfolds the distinction between distinction, form and decision in systems theory and in the system-theoretical observation of the law. The article then discusses Luhmann’s description of the functioning of decision(-making) within the legal system. The hypothesis is that Luhmann blends here cognitive with ethical aspects. Finally, the article addresses Luhmann’s polemics against alternative approaches to his own. The suggestion is that ‘judgment’, in Luhmann’s systems theory, re-enters by the back door as an ethical–theoretical imperative that commands theory’s responsibility for society and law