1. Until recently, the view that they are was common in classical moral theology and scholastic philosophy, and it is still held by some Catholic theologians and philosophers trained in the older approach. It was developed by Francisco Suarez, S.J., and became dominant in the seventeenth century. Though actually quite different from St. Thomas’ understanding of natural law, many believed it to be his position.19 It can be called “scholastic natural-law theory,” to distinguish it from the more adequate account of natural law which will be presented in chapters five through ten.
2. What is most characteristic of scholastic natural-law theory is its notion of the objectivity of moral norms. The basic moral standard is simply human nature as it is given—given, of course, not to sense experience but to intellectual knowing. Moral goodness or badness can be discerned merely by comparing the essential patterns of possible human actions with the intelligible structure of human nature considered both in its inner complexity (human persons are vegetative, sentient, and rational in themselves) and in its extrinsic relationships (human persons are creatures, fellow creatures, and rulers of lower creation in their essential relationships). When compared with human nature, actions are seen either to conform or not conform to the requirements set by nature.
3. According to scholastic natural-law theory, knowing whether or not a possible action conforms with human nature is a matter of making a comparison. Thus, this judgment is a piece of theoretical knowledge and has the kind of necessity enjoyed by a fundamental law of nature. When the action is compatible with human nature, the judgment registers conformity; it registers nonconformity, intrinsic evil, when the action is incompatible with human nature in any of its essential aspects.
4. Of course, to become aware of one’s obligations it is not enough to observe the conformity or nonconformity between the action and one’s nature. More than this theoretical knowledge, one needs a basic requirement. According to the theory, this can be expressed in various ways: Follow reason, Act in accord with nature, or Do good and avoid evil. However formulated, the demand’s full meaning is grasped only when one sees it to be a message to the created subject from God’s sovereign will. And one sees nature itself as an effective moral norm only when one sees it as a sign of God’s will.20
5. This theory is unlike the divine command theory, criticized in question D above, in two ways. First, it provides a reason for God to require what he does—namely, that it suits our nature. Second, it claims to provide a way by which we can know what is good, so that morally upright choices are more than blind obedience. Thus scholastic natural-law theory is far more plausible and acceptable than a simple divine command theory.
6. Moreover, because it grounds morality in human nature, it is an improvement over all the other views considered up to now. Unlike the view criticized in A, which reduces moral judgment to feeling, it makes judgment a matter of knowledge and truth. Unlike the view criticized in B, which excludes the possibility of moral reasoning by reducing moral judgments to isolated insights, scholastic natural-law theory indicates a source of principles from which one can reason. Unlike the subjectivist theory criticized in C, this theory confronts our freedom with objective norms. And unlike the cultural relativism criticized in question E, it gives morality a basis which transcends the diversity of cultural norms in different places and times and makes it possible to criticize the standards of every society, including one’s own.
7. Furthermore, nature does indeed have a certain normativity. A stomach, for instance, is made for digesting. From such natural normativity certain requirements follow: for example, the laws of diet. Thus one can know, for example, that it is appropriate for monkeys to eat bananas. It seems reasonable to imagine that, studying human nature by a similar though more complicated process of inquiry, one can determine what is existentially right and wrong for human persons.
8. This theory takes on still more plausibility in a theological context. It seems to fit the truth of faith that human persons are made in God’s image and so are by nature like him. It seems to explain the natural law written in our hearts by God when he made us.
9. But scholastic natural-law theory must be rejected. It moves by a logically illicit step—from human nature as a given reality, to what ought and ought not to be chosen.21 Its proponents attempt to reinforce this move, from what is to what ought to be, by appealing to God’s command. But for two reasons this fails to help matters. First, unless there is a logically prior moral norm indicating that God’s commands are to be obeyed, any command of God considered by itself would merely be another fact which tells us nothing about how we ought to respond. Second, even leaving this problem aside, the difficulty remains that human persons are unlike other natural entities; it is not human nature as a given, but possible human fulfillment which must provide the intelligible norms for free choices.
10. By such choices, human persons are of themselves. Human existence is more than conforming to a built-in pattern, as monkeys do when they eat bananas and otherwise do what comes naturally. Scholastic natural-law theory tells human persons: “Here you are—here is your nature—now be what you are.” Such advice can have a true sense, but unless human persons have possibilities which are not yet defined, there is no room for them to unfold themselves through intelligent creativity and freedom.
It is a sign of the basic flaw in scholastic natural-law theory that it provided only question-begging arguments for specific norms of Christian morality. Against contraception, for instance, it argued that this practice perverts the generative faculty by using it while frustrating its natural power to initiate new life. In reply, people reasonably note that perverting faculties in this sense cannot always be wrong—no one objects to the use of earplugs or chewing sugarless gum. As people chew sugarless gum for the pleasure of chewing, apart from nutrition, why should they not also engage in sexual activity for some human purpose such as celebrating marital unity, while excluding other purposes which at the moment cannot appropriately be pursued?
19. An accessible presentation of scholastic natural-law theory, by a proponent: Thomas J. Higgins, S.J., Man as Man: The Science and Art of Ethics, rev. ed. (Milwaukee: Bruce, 1958), 14–146. The chief source of this type of theory is Francisco Suarez, S.J., De legibus ac de Deo legislatore; the most relevant passages are in: Suarez, Selections from Three Works, ed. J. B. Scott, The Classics of International Law, 20 (Oxford: Clarendon Press, 1944). A good historical study of natural law, which divides Catholic theories from others, although still confusing Thomistic and Suarezian approaches: Heinrich A. Rommen, Natural Law: A Study in Legal and Social History and Philosophy (St. Louis: B. Herder, 1947). For an account of the differences between the Suarezian and Thomistic theories: Germain Grisez, “The First Principle of Practical Reason: A Commentary on the Summa theologiae, 1–2, Question 94, Article 2,” Natural Law Forum, 10 (1965), 168–201. The historical roots of scholastic natural-law theory as distinct from that of Thomas are traced more fully by John Finnis, Natural Law and Natural Rights (Oxford: Clarendon Press, 1980), 43–47, 54–57, and 348–50, who shows that Gabriel Vasquez and Francisco de Vitoria probably contributed to the development of the displacement of moral obligation from human practical reason to divine will.
20. According to Suarez, law is “the act of a just and right will by which the superior wills to oblige the inferior to do this or that” (De legibus ac de Deo legislatore, I, 5, 24). Thus the eternal law of God, which is the supreme norm of morality, is an act of God’s will decreeing observance of a certain order (II, 1, 5; II, 3, 1; II, 3, 5–6). In God, natural law is identical with the eternal law, decreeing that creatures conform to their natures (II, 5, 14). But in the rational creature, Suarez distinguishes between the nature as the foundation of the law and reason itself, which observes what agrees or disagrees with nature; the latter is the law (II, 4, 3; II, 5, 9 and 14). Thus for Suarez, natural law is not identified with human will, but rather with human reason; yet the obligatory character of the norms imposed by reason—which makes mere observations of conformity to or disconformity from nature into precepts—derives not from human reason but from the divine will (II, 6, 8).
21. St. Thomas was careful to explain that practical conclusions always must be resolved into practical principles which are distinct from and irreducible to theoretical ones: S.t., 1, q. 79, a. 12; 1–2, q. 94, a. 2; 2–2, q. 47, a. 6. To try to derive propositions containing “ought” from premises none of which contains or implies “ought” is a formal, logical fallacy. Counterexamples often suppress a premise: “The house is on fire; therefore, you ought to get out,” assumes that one ought to leave a burning house. Other counterexamples work by smuggling an “ought” into an apparently descriptive premise: “This act is uncharitable; therefore, you should not do it,” follows because the uncharitable by definition is to be avoided. Arguments from what is natural to what should be done are notorious examples of equivocation; “natural” is used descriptively in the premises but normatively in the conclusions, and so these arguments have four terms. The fact that nature can be understood (as it is by Aristotle) purposively does not help matters, for the normativity characteristic of nature is that of a type for its instances, while moral normativity is a requirement set by a judgment upon free choice between open alternatives.