In contrast to the uncompromising separation between natural law and legal positivism in Kelsen’s work, Hartian and Hartian-influenced legal positivism typically focuses or turns upon the degree to which law and morality occupy discrete, or, in the alternative, intersecting domains; with, broadly, exclusive legal positivists inclined to complete separation, and inclusive (or soft) legal positivists comprehending varying degrees of interconnectedness between law and morality. In this setting, the contention, maintained by inclusive legal positivists, that natural law and positive law may be reconciled and integrated within a single, unified and internally coherent legal positivism, has led to a re-examination of legal theory’s operational terminology. The rigidity of the designations ‘exclusive’ and ‘inclusive’ legal positivism has, accordingly, begun to dissolve and to be subsumed under the more expansive notion of ‘non-positivism’. This is particularly evident in Joseph Raz, where the detachment from, or repudiation of, the definitional categories of legal positivism and natural law seeks to free legal theory from its traditional conceptual moorings and to enable reconsideration of the essence, nature and content of law. The conceptual space in Raz’s work for the re-conceptualisation of elementary questions in legal theory is confronted, through a critical exchange with Robert Alexy, by an insistence upon the continued significance of the irreconcilability between natural law and legal positivism. Raz’s and Alexy’s respective positions arise, initially, from Raz’s 2007 critique of Alexy’s The Argument from Injustice: A Reply to Legal Positivism (2002), and from Alexy’s 2007 response to the Razian critique. The contemporary applicability of, or dissociation from, not only the designations ‘natural law’ and ‘legal positivism’ but also a decidedly Kelsenian legal positivism, with its concomitant Kelsenian antipathy to natural law theories, is instantiated in the exchange between Raz and Alexy. This chapter subjects Alexyan and Razian legal thought to close scrutiny, adopting a perspective in which the Kelsenian legal science of positive law is evident. In so doing, the authors contend that Kelsenian legal positivism has continued pertinence not only for attempts to comprehend law’s contours, character and nature but also for contemporary legal theory