The Natural Law Tradition in Ethics in United States

Murphy, Mark, “The Natural Law Tradition in Ethics”, The Stanford Encyclopedia of Philosophy (Winter 2011 Edition), Edward N. Zalta (ed.), URL = .

The Natural Law Tradition in Ethics

‘Natural law theory’ is a label that has been applied to theories of ethics, theories of politics, theories of civil law, and theories of religious morality. We will be concerned only with natural law theories of ethics: while such views arguably have some interesting implications for law, politics, and religious morality, these implications will not be our focus here.

This article has two central objectives. First, it aims to identify the defining features of natural law moral theory. Second, it aims to identify some of the main theoretical options that natural law theorists face in formulating a precise view within the constraints set by these defining features and some of the difficulties for each of these options. It will not, however, attempt to recount the history of the development of natural law thought. (For a very helpful detailed history of natural law thought up to the beginning of the modern period, see Crowe 1977. For a very helpful detailed history of natural law thought in the modern period, see Haakonssen 1996. For an article-length recap of the entire history of natural law thought, see Haakonssen 1992.)

1. Key Features of Natural Law Theories
1.1 Natural law and divine providence
1.2 Natural law and practical rationality
1.3 The substance of the natural law view
1.4 Paradigmatic and nonparadigmatic natural law theories
2. Theoretical Options for Natural Law Theorists
2.1 Natural goodness
2.2 Knowledge of the basic goods
2.3 The catalog of basic goods
2.4 From the good to the right
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1. Key Features of Natural Law Theories

Even though we have already confined ‘natural law theory’ to its use as a term that marks off a certain class of ethical theories, we still have a confusing variety of meanings to contend with. Some writers use the term with such a broad meaning that any moral theory that is a version of moral realism — that is, any moral theory that holds that some positive moral claims are literally true (for this conception of moral realism, see Sayre-McCord 1988)— counts as a natural law view. Some use it so narrowly that no moral theory that is not grounded in a very specific form of Aristotelian teleology could count as a natural law view. It might be thought that there is nothing that can be done to begin a discussion of natural law theory in ethics other than to stipulate a meaning for ‘natural law theory’ and to proceed from there. But there is a better way of proceeding, one that takes as its starting point the central role that the moral theorizing of Thomas Aquinas plays in the natural law tradition. If any moral theory is a theory of natural law, it is Aquinas’s. (Every introductory ethics anthology that includes material on natural law theory includes material by or about Aquinas; every encyclopedia article on natural law thought refers to Aquinas.) It would seem sensible, then, to take Aquinas’s natural law theory as the central case of a natural law position: of theories that exhibit all of the key features of Aquinas’s natural law view we can say that they are clearly natural law theories; of theories that exhibit few of them we can say that they are clearly not natural law theories; and of theories that exhibit many but not all of them we can say that they are in the neighborhood of the natural law view but nonetheless must be viewed as at most deviant cases of that position. There remain, no doubt, questions about how we determine what are to count as the key features of Aquinas’s position. But we may take as the key features those theses about natural law that structure his overall moral view and which provide the basis for other theses about the natural law that he affirms.

For Aquinas, there are two key features of the natural law, features the acknowledgment of which structures his discussion of the natural law at Question 94 of the Prima Secundae of the Summa Theologiae. The first is that, when we focus on God’s role as the giver of the natural law, the natural law is just one aspect of divine providence; and so the theory of natural law is from that perspective just one part among others of the theory of divine providence. The second is that, when we focus on the human’s role as recipient of the natural law, the natural law constitutes the principles of practical rationality, those principles by which human action is to be judged as reasonable or unreasonable; and so the theory of natural law is from that perspective the preeminent part of the theory of practical rationality.
1.1 Natural law and divine providence

While our main focus will be on the status of the natural law as constituting the principles of practical rationality, we should consider for a moment at least the importance within Aquinas’s view of the claim that the natural law is an aspect of divine providence. The fundamental thesis affirmed here by Aquinas is that the natural law is a participation in the eternal law (ST IaIIae 91, 2). The eternal law, for Aquinas, is that rational plan by which all creation is ordered (ST IaIIae 91, 1); the natural law is the way that the human being “participates” in the eternal law (ST IaIIae 91, 2). While nonrational beings have a share in the eternal law only by being determined by it — their action nonfreely results from their determinate natures, natures the existence of which results from God’s will in accordance with God’s eternal plan — rational beings like us are able to grasp our share in the eternal law and freely act on it (ST IaIIae 91, 2). It is this feature of the natural law that justifies, on Aquinas’s view, our calling the natural law ‘law.’ For law, as Aquinas defines it (ST IaIIae 90, 4), is a rule of action put into place by one who has care of the community; and as God has care of the entire universe, God’s choosing to bring into existence beings who can act freely and in accordance with principles of reason is enough to justify our thinking of those principles of reason as law.
1.2 Natural law and practical rationality

When we focus on the recipient of the natural law, that is, us human beings, the thesis of Aquinas’s natural law theory that comes to the fore is that the natural law constitutes the basic principles of practical rationality for human beings, and has this status by nature (ST IaIIae 94, 2). The notion that the natural law constitutes the basic principles of practical rationality implies, for Aquinas, both that the precepts of the natural law are universally binding by nature (ST IaIIae 94, 4) and that the precepts of the natural law are universally knowable by nature (ST IaIIae 94, 4; 94, 6).

The precepts of the natural law are binding by nature: no beings could share our human nature yet fail to be bound by the precepts of the natural law. This is so because these precepts direct us toward the good as such and various particular goods (ST IaIIae 94, 2). The good and goods provide reasons for us rational beings to act, to pursue the good and these particular goods. As good is what is perfective of us given the natures that we have (ST Ia 5, 1), the good and these various goods have their status as such naturally. It is sufficient for certain things to be good that we have the natures that we have; it is in virtue of our common human nature that the good for us is what it is.

The precepts of the natural law are also knowable by nature. All human beings possess a basic knowledge of the principles of the natural law (ST IaIIae 94, 4). This knowledge is exhibited in our intrinsic directedness toward the various goods that the natural law enjoins us to pursue, and we can make this implicit awareness explicit and propositional through reflection on practice. Aquinas takes it that there is a core of practical knowledge that all human beings have, even if the implications of that knowledge can be hard to work out or the efficacy of that knowledge can be thwarted by strong emotion or evil dispositions (ST IaIIae 94, 6).

If Aquinas’s view is paradigmatic of the natural law position, and these two theses — that from the God’s-eye point of view, it is law through its place in the scheme of divine providence, and from the human’s-eye point of view, it constitutes a set of naturally binding and knowable precepts of practical reason — are the basic features of the natural law as Aquinas understands it, then it follows that paradigmatic natural law theory is incompatible with several views in metaphysics and moral philosophy. On the side of metaphysics, it is clear that the natural law view is incompatible with atheism: one cannot have a theory of divine providence without a divine being. It is also clear that the paradigmatic natural law view rules out a deism on which there is a divine being but that divine being has no interest in human matters. Nor can one be an agnostic while affirming the paradigmatic natural law view: for agnosticism is the refusal to commit either to God’s existence or nonexistence, whereas the paradigmatic natural law view involves a commitment to God’s existence. On the side of moral philosophy, it is clear that the natural law view is incompatible with a nihilism about value, that is, the rejection of the existence of values. It is also incompatible with relativist and conventionalist views, on which the status of value is entirely relative to one’s community or determined entirely by convention. It is also incompatible with a wholesale skepticism about value, for the natural law view commits one to holding that certain claims about the good are in fact knowable, indeed, knowable by all.
1.3 The substance of the natural law view

The center of Aquinas’s natural law view as described thus far concerns what we might call the metaphysics of morals: its role in divine providence and the universally authoritative character of its norms. What, though, of the normative content of Aquinas’s natural law position? Is there anything distinctive about the normative natural law position? Here it is difficult to say much that is uncontroversial, but we can say a sufficient amount about Aquinas’s natural law theory to make clear that it is an interesting alternative to utilitarian (and more generally consequentialist) ethics, Kantian views, and standard Aristotelian positions. (For a magisterial treatment of Aquinas’s natural law ethic, see Rhonheimer 2000.)

Aquinas says that the fundamental principle of the natural law is that good is to be done and evil avoided (ST IaIIae 94, 2). This is, one might say, a principle of intelligibility of action (cf. Grisez 1965): only action that can be understood as conforming with this principle, as carried out under the idea that good is to be sought and bad avoided, can be understood as an intelligible action. But no one can in acting simply pursue good — one has to pursue some particular good. And Aquinas holds that we know immediately, by inclination, that there are a variety of things that count as good and thus to be pursued — life, procreation, knowledge, society, and reasonable conduct (ST IaIIae 94, 2; 94, 3) are all mentioned by Aquinas (though it is not clear whether the mentioned items are supposed to constitute an exhaustive list).

So on Aquinas’s view it is the good that is fundamental: whether an action, or type of action, is right is logically posterior to whether that action brings about or realizes or is some good. The good is, on Aquinas’s view, prior to the right. But on Aquinas’s view we are, somehow, able to reason from these principles about goods to guidelines about how these goods are to be pursued. Aquinas’s thoughts are along the following lines: first, there are certain ways of acting in response to the basic human goods that are intrinsically flawed; and second, for an act to be right, or reasonable, is for it to be an act that is in no way intrinsically flawed (ST IaIIae 18, 1).

The important task, then, is to identify the ways in which an act can be intrinsically flawed. Aquinas does not obviously identify some master principle that one can use to determine whether an act is intrinsically flawed (though for an attempt to identify such a master principle in Aquinas’s work see Finnis 1998, p. 126), though he does indicate where to look — we are to look at the features that individuate acts, such as their objects (ST IaIIae 18, 2), their ends (ST IaIIae 18, 3), their circumstances (ST IaIIae 18, 4), and so forth. An act might be flawed through a mismatch of object and end — that is, between the immediate aim of the action and its more distant point. If one were, for example, to regulate one’s pursuit of a greater good in light of a lesser good — if, for example, one were to seek friendship with God for the sake of mere bodily survival rather than vice versa — that would count as an unreasonable act. An act might be flawed through the circumstances: while one is bound to profess one’s belief in God, there are certain circumstances in which it is inappropriate to do so (ST IIaIIae 3, 2). An act might be flawed merely through its intention: to direct oneself against a good — as in murder (ST IIaIIae 64, 6), and lying (ST IIaIIae 110, 3), and blasphemy (ST IIaIIae 13, 2) — is always to act in an unfitting way. Aquinas has no illusions that we will be able to state principles of conduct that exhaustively determine right conduct, as if for every situation in which there is a correct choice to be made there will be a rule that covers the situation. He allows for the Aristotelian insight that the particulars of the situation always outstrip one’s rules, so that one will always need the moral and intellectual virtues in order to act well (Commentary on NE, II, 2, 259). But he denies that this means that there are no principles of right conduct that hold everywhere and always, and some even absolutely. On Aquinas’s view, killing of the innocent is always wrong, as is lying, adultery, sodomy, and blasphemy; and that they are always wrong is a matter of natural law. (These are only examples, not an exhaustive list of absolutely forbidden actions.)

Part of the interest of Aquinas’s substantive natural law ethic lies in its not falling into the neat contemporary categories for moral theories. His natural law view understands principles of right to be grounded in principles of good; on this Aquinas sides with utilitarians, and consequentialists generally, against Kantians. But Aquinas would deny that the principles of the right enjoin us to maximize the good — while he allows that considerations of the greater good have a role in practical reasoning, action can be irremediably flawed merely through (e.g.) badness of intention, flawed such that no good consequences that flow from the action would be sufficient to justify it — and in this Aquinas sides with the Kantians against the utilitarians and consequentialists of other stripes. And while Aquinas is in some ways Aristotelian, and recognizes that virtue will always be required in order to hit the mark in a situation of choice, he rejects the view commonly ascribed to Aristotle (for doubts that it is Aristotle’s view; see Irwin 2000) that there are no universally true general principles of right. The natural law view rejects wholesale particularism.
1.4 Paradigmatic and nonparadigmatic natural law theories

To summarize: the paradigmatic natural law view holds that (1) the natural law is given by God; (2) it is naturally authoritative over all human beings; and (3) it is naturally knowable by all human beings. Further, it holds that (4) the good is prior to the right, that (5) right action is action that responds nondefectively to the good, that (6) there are a variety of ways in which action can be defective with respect to the good, and that (7) some of these ways can be captured and formulated as general rules.

Aquinas was not the only historically important paradigmatic natural law theorist. Thomas Hobbes, for example, was also a paradigmatic natural law theorist. He held that the laws of nature are divine law (Leviathan, xv, ¶41), that all humans are bound by them (Leviathan, xv, ¶¶36), and that it is easy to know at least the basics of the natural law (Leviathan, xv, ¶35). He held that the fundamental good is self-preservation (Leviathan, xiii, ¶14), and that the laws of nature direct the way to this good (Leviathan, xiv, ¶3). He offered a catalog of laws of nature that constitute the “true moral philosophy” (Leviathan, xv, ¶40). There are also a number of contemporary writers that affirm the paradigmatic view. These writers, not surprisingly, trace their views to Aquinas as the major influence, though they do not claim to reproduce his views in detail. (See, for example, Grisez 1983, Finnis 1980, MacIntyre 1999, and Murphy 2001.)

It is also easy to identify a number of writers, both historical and contemporary, whose views are easily called natural law views, through sharing all but one or two of the features of Aquinas’s paradigmatic position. Recently there have been nontheistic writers in the natural law tradition, who deny (1): see, for example, the work of Michael Moore (1982, 1996) and Philippa Foot (2001). There were a number of post-Thomistic writers in the medieval and modern periods who in some way denied (2), the natural authority of the natural law, holding that while the content of the natural law is fixed either wholly or in part by human nature, its preceptive power could only come from an additional divine command: the views of John Duns Scotus, Francisco Suarez, and John Locke fit this mold. Arguably the Stoics were natural law thinkers, but they seem to deny (4), holding the right to be prior to the good (see Striker 1986). Some contemporary theological ethicists called ‘proportionalists’ (e.g. Hallett 1995) have taken up the natural law view with a consequentialist twist, denying (6). (For a discussion of the relationship between proportionalism and natural law theory see Kaczor 2002.) And while some see Aristotle as being the source of the natural law tradition, some have argued that his central appeal to the insight of the person of practical wisdom as setting the final standard for right action precludes the possibility of the sort of general rules that would (at least in a theistic context) make Aristotle’s ethics a natural law position. There is of course no clear answer to the question of when a view ceases to be a natural law theory, though a nonparadigmatic one, and becomes no natural law theory at all.

Continue: Theoretical Options for Natural Law Theorists