THE FIRST PRINCIPLE OF PRACTICAL REASON IN THOMAS AQUINAS

THE CONTEMPORARY DEBATE ON THE STARTING POINT OF NATURAL LAW

Abstract

Objective: This article investigates Thomas Aquinas' theory of natural law. Specifically, it aims to (1) expose how Aquinas approaches the first principle of practical reason; (2) expose the interpretation that the philosophers and legal philosophers constituting the New School of Natural Law offer regarding the aforementioned principle; (3) expose the main disagreements regarding the interpretation of the New School of Natural Law; (4) argue why the New School's interpretation fits Aquinas's approach; and (5) expose the difficulties in alternative interpretations.

Method: Theoretical and reflective approach according to authorized and updated bibliography. It uses the lessons of Thomas Aquinas and his contemporary interpreters, with emphasis on those who constitute the New School of Natural Law.

Result: Traditional derivationist positions are not able to adequately explain human acts. And this is because they do not explain the practical directive provided by the first practical principle in an act considered immoral. Furthermore, an additional hermeneutical argument is presented in favor of the interpretation of the New School of Natural Law regarding the first practical principle in Aquinas: considering the undeniable influence of Aristotle on Aquinas's work and a relative continuity between both, it is clear that there is a very similar thesis defended by both – formulated in different ways – and which makes the interpretation of the neoclassical theory of natural law more consistent. Thus, the role of the first principle of practical reason is understood as a structuring and directive principle of human acts in general, whether for acts considered morally appropriate or for acts considered morally inadequate.

Contributions: The following lines bring together preliminary notes, notwithstanding technical ones. Its contribution goes back to the necessary advancement of studies attentive to the structure of human reason, which has a theoretical aspect, which seeks to know the truth of things and philosophical propositions, and a practical aspect, which seeks to guide human acts towards certain ends. Furthermore, this article also contributes to the gaps in national literature at a philosophical-legal and ethical level, making it indispensable for a holistic view of the lessons of the main exponent of the natural law tradition – Thomas Aquinas.