This study is a response to the observation of the critical importance of human rights in the ethical discourse of the public sphere. Yet despite the broad consensus, there exists a plurality of approaches to their exposition and justification; each bound to a particular way of moral reasoning. A thorough consideration of rights in moral theology requires that such models be taken seriously. To this end, it presents a comparative investigation of three theorists, each representative of a different tradition of enquiry: namely, John Finnis and the Natural Law tradition, Ronald Dworkin and the Liberal Tradition, and Jürgen Habermas and the Critical Tradition. It unfolds in four stages (guided by the methodological categories of Bernard Lonergan). The first part, titled «History», maps the central impulses, texts and values that help shape each tradition of enquiry. The second part, «Interpretation», provides a detailed exposition of each of the central theorists. The third part, «Dialectic», embarks on a comparative study that outlines points of convergence and paths of divergence; leading to a final judgement in favour of the Natural Law tradition of enquiry. The final part, «Foundation», considers the theological reasons commonly proposed for supporting human rights in light of the previous study.