The Light That Binds

A Study in Thomas Aquinas's Metaphysics of Natural Law

Stephen L. Brock

• Publisher: Pickwick Publications
• Year: 2020
• Print ISBN: 9781532647291, 9781532647307
• eBook ISBN: 9781532647314
• Topic: Theology & Religion
• Subtopic: Christian Theology

If there is any one author in the history of moral thought who has come to be associated with the idea of natural law, it is Saint Thomas Aquinas. Many things have been written about Aquinas's natural law teaching, and from many different perspectives. The aim of this book is to help see it from his own perspective. That is why the focus is metaphysical. Aquinas's whole moral doctrine is laden with metaphysics, and his natural law teaching especially so, because it is all about first principles. The book centers on how Aquinas thinks the first principles of practical reason, which for him are what make up natural law, function as laws. It is a controversial question, and the book engages a variety of readers of Aquinas, including Francisco Suarez, Jacques Maritain, prominent analytical philosophers, Straussians, and the initiators of the New Natural Law theory. Among the issues addressed are the relation between natural law and natural inclination, how far natural law depends on knowledge of human nature, what its obligatory force consists in, and, above all, how it is related to what for Aquinas is the first principle of all being, the divine will.

1

The Question of the Legal Character of Natural Law

The question is how the definition of law that Thomas Aquinas lays out in the Summa theologiae is meant to be applied to what he calls natural law.

Anyone moderately familiar with the section on law in the Summa theologiae, and not so familiar with the literature on natural law in Aquinas, may very well wonder why it is even a question. Can there be any doubt as to how his definition of law in general applies to natural law? Hardly any work of interpretation seems necessary.

In the very article in which he brings his definition of law to completion, Thomas says that “natural law has the nature of law to the highest degree (maxime).”1 It is true that he makes this assertion in one of the article’s objections, so that it cannot immediately be taken to express his own view. But the reply to the objection, far from denying the assertion or qualifying it in any way, only confirms it. It also seems to indicate rather clearly the precise manner in which natural law possesses the nature of law. The objection was against the proposition that promulgation belongs to the essence of law. Natural law, it said, is law to the highest degree, and yet needs no promulgation at all. The reply simply denies that natural law is without promulgation. If natural law stands in no need of promulgation, the reason is that it has been promulgated already, “by the very fact that God has inserted it into the minds of men as something to be naturally known.”2 With this statement, how natural law fits under Thomas’s definition of law in general seems quite easy to see. That definition, given in the same article, is “an ordination of reason, for the common good, promulgated by him who has care of the community.”3 Natural law, then, would be an ordination of divine reason, for the common good of the universe, promulgated to man by God as governor of the universe, through the instilling of the natural light of the human intellect.4

Two articles later, Thomas offers a rigorous argument to show the existence of a natural law in us. It concludes with his description of natural law as “nothing other than a participation of the eternal law in the rational creature.”5 Taken as a whole and as it exists in His own mind, the ordination by which God governs the universe is called the eternal law. This certainly fits the definition of law. And in the reply to the article’s first objection, Thomas insists that natural law is not something diverse from the eternal law, but only a certain participation in it.

Still, unequivocal as these texts seem, Aquinas’s subsequent treatment of natural law does raise one or two questions. The article that presents natural law as a participation of the eternal law in the rational creature belongs to a quaestio devoted to the “division of law.” A little further on, Thomas devotes an entire quaestio to the subject of natural law.6 There he determines what sort of entity in man’s mind it consists in, whether it has one or many precepts, and other characteristics of it. The curious thing is that, in this whole quaestio, the eternal law is not mentioned even once. Nor is its having God as its author—even though God’s being Lord of the universe and author of a divine, supernaturally transmitted law is mentioned.7 Natural law is treated entirely on the human or natural level and is not referred to God at all.

This is one consideration that has led some interpreters to regard the description of natural law in terms of the eternal law as a mere function of Aquinas’s theological procedure, and not as his strict or sole definition of it. Nor is it the only such consideration. Alan Donagan offers others:

From the fact that St Thomas, in a theological work, defines natural law theologically, it follows neither that it cannot be defined philosophically, nor that a philosophical definition would be incomplete, as, according to St Thomas, any account of the natural end of man that neglected divine revelation would be incomplete. Although this is not stated in terms by Aquinas, it is implied by his assertion that “all men know . . . the common principles of the natural law” [I–II.93.2]. It is also presupposed in his derivations of the various precepts of the natural law, in none of which does he make any appeal to revealed theology. Nor does he explicitly draw upon natural theology, except in deriving precepts having to do with divine worship.8

Donagan refers to Aquinas’s derivations of the various precepts of natural law. Usually article 2 of ST I–II.94 is taken to lay the groundwork for these derivations. This article focuses entirely on things pertaining to human nature: the theoretical and practical truths naturally grasped by human reason and the natural inclinations of the human agent. The term natural law, as it is used there, appears to signify nothing other than the first principles of practical reason. Moreover, Thomas nowhere says that people need to have learned of God’s legislative activity before they can grasp the truth of the first principles of practical reason. These principles are naturally per se nota, self-evident, to everyone.9 By contrast, God’s universal providence and legislation, on Thomas’s view, are not naturally self-evident to us. This is the point that Donagan is making with his reference to Aquinas’s assertion that all men know the common principles of the natural law.

The question that Donagan’s claim raises is the following. Can an account of natural law that makes no mention of God, or of the eternal law, still present natural law as a law in the full sense, according to Thomas’s definition of law? It seems...

Table of contents

• Title Page
• Abbreviations and References
• Introduction
• 1. The Question of the Legal Character of Natural Law
• 2. The Relation between Natural Law and Eternal Law
• 3. Natural Law, God’s Will, and Positive Law
• 4. Natural Inclinations in the Promulgation of Natural Law
• 5. Nature and Human Nature in the Promulgation of Natural Law
• 6. The Force of Natural Law
• 7. The Naturalness of Natural Law
• Bibliography