Thomas Aquinas on the Old Law and the Natural Law

Thomas Aquinas on the Old Law and the Natural Law

Anton Pegis has argued forcefully that the philosophy of the Middle Ages was a philosophy imbedded within a theology. As he has pointed out, the various philosophies of the Middle Ages "were created by theologians within theology and for the purposes of theology; in short, they were created as parts of theology itself." Schoolmen such as Thomas, claims Pegis, "did not learn philosophy from Aristotle in order to become philosophers, even Christian philosophers; they learned philosophy in order to use it as the appropriate rational tool in the formation of what was for them a Christian theology."

I suggest that Pegis's thesis is borne out by an historical study of Thomas Aquinas's treatment of the natural law. A close reading of that tradition suggests that Thomas's philosophy of the natural law is, as Pegis suggests, a philosophy imbedded within a theology.

I cannot hope to prove or disprove this thesis, of course, in a short talk, but I will make a first step at elucidating it by showing how, for Thomas Aquinas, the basic principles of the natural law are revealed in and through the Christian Scriptures and how Thomas's understanding of the natural law depends upon a particularly Christian theology of history.

1. How the Old Law Shows Forth the Precepts of the Natural Law

The working premise of this paper is that, as Thomas Aquinas[1] says, "the Old Law shows forth the precepts of the natural law." Now at first glance, it appears that these two -- the Old Law and the natural law -- couldn't be any more diametrically opposed. The natural law was traditionally conceived of as an "unwritten law," an agraphos nomos. So, for example, Thucydides[2], in the great Funeral Oration of Pericles, speaks of obedience to those laws which "although unwritten, yet cannot be broken without acknowledged disgrace." On this classical view, the natural law was "unwritten" because it was known intuitively by all. As such, it was shared in common by all men and distinguished, in this respect, from the written positive laws that applied only to individual cities or countries.[3] Thus Aristotle[4], in the Rhetoric, tells his reader: "Now the law is particular or general. By particular I mean the written law in accordance with which a state is administered; by general, the unwritten regulations which appear to be universally recognized." And still much later, the Jewish philosopher Philo of Alexandria[5] will speak of the "unwritten law" which was written on the hearts and reflected in the lives of the virtuous Patriarchs of the Old Testament, who lived before the advent of the written law.

Before any at all of the particular statutes was set in writing, [the Patriarchs] followed the unwritten law with perfect ease, so that one might properly say that the enacted laws are nothing else than memorials of the life of the ancients ... [who] gladly accepted conformity with nature, holding that nature itself was, as indeed it is, the most venerable of statutes, and thus their whole life was one of happy obedience to law.

The Old Law, on the other hand, from the time of its origins among the Hebrew People who followed Moses into the wilderness, was identified precisely as a law written down: at first, literally chiselled into stone and carried about in the Ark of the Covenant, and later, written upon scrolls and read aloud regularly before the assembled community. Indeed, reading from this written law, the Torah, remains a center-piece of Jewish religious practice.

So, although the "unwritten" natural law and the "written" Old Law may seem diametrically opposed at first glance, yet as the passage from Philo cited above shows, there were some who attempted to relate the two. Indeed, Thomas Aquinas, as will become clear, is someone who attempted to do just that. Now it may be that we can never fully reconcile the differences between the "written" and the "unwritten" law; indeed, I would argue that the differences between the two can finally only be resolved by the gift of the New Law, when the natural law is written anew on men's hearts by the work of the Holy Spirit. Nevertheless, for Thomas, an important and essential relationship exists between the Old Law and the natural law. It is a relationship of disclosure.

To state the premise of the paper more precisely, let us say then that, for Thomas Aquinas, the moral precepts of the Old Law articulate in a written way what the natural law expresses in an unwritten way. Or to express the same thing in still other terms, we might say that the moral precepts of the Old Law express materially -- that is, in words -- the essential teaching (the doctrina) of the natural law. On Thomas's account, the source of their unity is that they are two expressions of God's single will. God, who is the author of both the Book of Nature and the Book of Scripture, has revealed the fundamental precepts of the natural law in a written way in the moral precepts of the Old Law. To understand how the natural law and the Old Law are related, however, we must begin by recognizing a key distinction.

Thomas distinguishes three basic types of precept in the Old Law: moral, ceremonial, and judicial.[6] The ceremonial and judicial precepts, though related to the natural law, were binding only on the Jewish people and only until the coming of Christ. The moral precepts, on the other hand, are binding on all people at all times because, according to Thomas, they "belong to the law of nature" (de lege naturae).[7] Indeed, the identity between the moral precepts of the Old Law and the natural law is expressed in particularly strong terms. In q.99,a.4 of the prima secundae of the Summa, for example, Thomas says that the moral precepts refer to the dictamen of the natural law (ad dictamen legis naturae, ad quod referuntur moralia praecepta). He uses the same term when he distinguishes the moral precepts from the judicial and ceremonial precepts in q.104,a.1. He says there of the moral precepts that they "derive their binding force from the dictamen of reason itself (habent vim obligandi ex ipso dictamine rationis).[8] Now this term, dictamen, carries strong connotations in Latin which we have trouble capturing with any single English term. Often, the English terms "utterance," "statement," or "dictum" are forced into service.[9] In the Latin Middle Ages, however, the term dictamen referred primarily to a written dictation, taken down by a scribe, which represented in writing an authoritative statement, usually from a superior to his subordinates.[10] The scribal art of taking dictation was, in fact, called the ars dictaminis. In Lewis and Short's Oxford Latin Dictionary, we find under the entry for dictamen the following: "late Latin for dictum, praescriptum," and most tellingly, "praeceptum." Why a praeceptum, a "precept"? Because a dictamen, in addition to being a precise written account of someone's words (their dicta, as it were), carries with it a clear authority of command -- the authority of the one whose words have been so scrupulously recorded -- and thus constitutes for those under his authority a "precept" or a "command". I suggest, therefore, that we can say of the moral precepts of the Old Law that they are a written articulation of what the natural law expresses in an unwritten way, just as a medieval dictamen was a written dictation of a command that was expressed originally in an unwritten way.

2. Man's Need for a Revealed Articulation of the Natural Law

But why would anyone need this special, revealed articulation of the precepts of the natural law? After all, the natural law is known "naturally", is it not? Thomas himself says of the natural law that it pertains to "the light of natural reason" (the lumen rationis naturalis).[11] If man's natural reason, operating by its own lights, is sufficient to grasp the precepts of the natural law, then isn't the Old Law merely superfluous, serving no good purpose?

Thomas answers this very objection in q.99,a.2 of the prima secundae. The article's second objection asserts that man's reason is sufficient for grasping moral precepts; therefore, there is no need for the Old Law to contain any moral precepts. Thomas's response is that divine revelation comes to man's assistance not only in matters where his reason is insufficient, such as in matters of faith, but also in those matters where his reason may have been impeded or obscured.[12] In this regard, the moral precepts are like the praeambula fidei that Thomas describes at the beginning of the Summa: God must reveal them, otherwise the knowledge of these truths upon which man's whole salvation depends "would be known only by a few, and that after a long time, and with the admixture of many errors."[13] For human reason, says Thomas, through being habituated to sin, "became darkened as to what ought to be done" and "went astray, to the extent of judging to be lawful things that are evil in themselves."

But how did this happen? How did we become habituated to error and the natural power of our intellects thus darkened to what is good and evil? The answer is that our natural powers have been corrupted by sin, especially original sin. As Thomas often explains, one must consider human nature in two ways. In the first way, we can think of human nature in its full integrity or wholeness (in sui integritate), as it was in the first man before he sinned. Secondly, however, there is human nature as it exists in us now, corrupted due to original sin (corrupta in nobis post peccatum primi parentis).[14] At his creation, before the fall, man was able to act in accord with the natural law. It was at that point, says Thomas[15], "according to his proper natural condition that [man] should act in accordance with reason"; indeed, "this law was so effective in man's first state, that nothing either outside or against reason could take man unawares." After man turned away from God, however, "he fell under the influence of his sensual impulses," which began to rule him as though they themselves were a kind of law. This law -- what Thomas calls in the Summa, the law of the fomes, and what he calls elsewhere, more simply, "the law of concupiscence" -- this law is "a deviation from the law of reason." The more man fell under its sway, the more he "departed from the path of reason" -- so much so that Thomas proclaims starkly that, "the law of nature was destroyed by the law of concupiscence."[16]

The result, according to Thomas[17], is that in his present fallen state, man is largely not able -- that is, no longer able -- to do the good proportioned to his nature.

In the state of integrity of nature [says Thomas] ... man by his natural endowments could will and do the good proportioned to his nature, which is the good of acquired virtue ... But in the state of corrupted nature, man falls short even of what he can do by his nature, so that he is unable to fulfill all of it by his own natural powers.[18]

For Thomas Aquinas, therefore, as for the medieval Christian tradition of which he is a part, the operations of human nature since the fall of man are not at all the workings of a well-oiled and efficient machine. Human nature has been so corrupted by the effects of sin that, what was characteristic or "natural" for man in that time when his nature was healthy and uncorrupted is no longer so. Man's acts and dispositions are the result of severely weakened capacities. Thus, when we talk about the natural law and, correspondingly, about the capacities of man's "natural" reason to arrive at independent moral judgments, we must remember that, for the actual world of living moral agents, what has become "natural" for us, according to Thomas, are the moral judgments that follow upon a wounded, corrupted nature, not those that depend upon an integral and uncorrupted nature that human beings no longer actually possess.

Thus, it precisely not the case, as the Jesuit scholar R.J. Henle[19] claims in his

commentary on Thomas's Treatise on Law, that:

If [man] were left to his natural powers, he could, by these powers alone, achieve some degree of happiness proportionate to his nature. In this case, the Natural Law and Human Law would be adequate to guide him in his human acts.

Quite to the contrary, Thomas makes clear that if man were left to his natural powers, he would, by these powers alone, not be very happy at all. How do we know this? Because we have a record of the results. According to Thomas, man's chief defect since the fall has been pride, and men are proud of two things: knowledge and power. In order that man's pride might be overcome, says Thomas[20], "man was left to the guidance of his reason alone without the help of a written law." Indeed, Thomas even calls this "the age of the natural law." Far from showing, as Fr. Henle claims, that "the Natural Law alone would be adequate to guide man in his human acts," the age of the natural law showed man how desperately inadequate his knowledge had become. The result, according to Thomas[21], was that "man fell headlong into idolatry and the most shameful vices." Knowledge of the natural law was obscured or obliterated so great was the "exhuberance of sin." And yet, because of this, says Thomas, "man was able to learn from experience [painful experience] that his reason was deficient." And God, out of His infinite mercy and love, responded then to man in his need by providing him with the Old Law "as a remedy for human ignorance" (in remedium humanae ignorantiae),[22] so that he might be instructed in the principles of the natural law, which he should know, were his nature not corrupted by sin.[23]

Since then the law of nature was destroyed by the law of concupiscence, man needed to be brought back to works of virtue, and to be drawn away from vice: for which purpose he needed the written law.

Dom Odon Lottin[24] has accurately described this theology of history as follows:

The school of Anselm of Lâon spread, on the subject of the natural law, a conception which exercised a profound influence. Before the epoch of the Mosaic Law, humanity was subject to the reign of the natural law, which naturalis ratio dictated to him. It was condensed into this principle: Do not do to another that which you would not want for him to do to you. [We will see this in Thomas as well.] But this natural reason was soon obfuscated by sin, to the point that few men remained faithful to the true God. The Mosaic Law, thus, became necessary to revive the natural law in the heart of man.

What Thomas has seen perhaps more clearly than any of his contemporaries,[25] however, is that if the moral precepts of the Old Law stand as a privileged revelation from God of the dictamen of the natural law, given to man as a salutary aid in light of his fallen state, then we should be able to use the moral precepts of the Old Law as an authoritative guide to the content of the natural law. It was for this exact reason, after all, that they were given to us by God.

3. Thomas's Threefold Hierarchy of Moral Precepts

Now the hierarchy that obtains among the moral precepts of the Old Law is laid out in a.1 of q.100 of the prima secundae and then repeated, almost verbatim, in aa.3 and 11. In each article, Thomas identifies three "levels" or "grades" (gradus is the Latin term) of moral precept in the Law. These are distinguished according to their degree of universality or particularity and thus according to their accessibility to human reason.

As every judgment of speculative reason proceeds from the natural knowledge of first principles, says Thomas[26], so every judgment of practical reason proceeds "from certain naturally known principles" (ex quibusdam principiis naturaliter cognitis). These principles of practical rationality are what Thomas calls "the first and common precepts of the natural law" (prima et communia praecepta legis naturae), "which are per se nota to human reason."[27] As per se nota, these precepts need not (and indeed cannot) be deduced from principles that are prior. Although there has been much debate among scholars about the primary precepts of the natural law,[28] Thomas, for his part, leaves us no doubt as to what he thinks they are. So, for example, in q.100,a.3, he says of the two great commandments to "love the Lord your God with all your heart, soul, and mind," and to "love your neighbor as yourself," that "these two precepts are the first and common precepts of the natural law, which are self-evident to human reason" (illa duo praecepta sunt prima et communia praecepta legis naturae, quae sunt per se nota rationi humanae)."[29] Thomas makes clear elsewhere that there are also other, alternative forms of this second commandment to "love your neighbor as yourself": namely, "Do unto others as you would have them do unto you," or the negative form of the same commandment: "Don't do to others what you wouldn't want them to do to you," or sometimes he says more simply, "Do harm to no one." Such commandments constitute for Thomas the primary precepts of the natural law.