Last year’s Synod on the Family lamented an almost universal lack of understanding of the concept of “natural law” among the faithful, a principle that the Church relies on for the bulk of its moral teaching, which she sees as being shared by all of humanity. Her teaching on marriage and on human reproduction makes copious reference to the natural law, as does her social teaching. As a result, I would here like to review the foundations of what natural law is, how it fits into the bigger picture of the Church’s teaching and how access to it works. Since, like any aspect of the Church’s teaching, the understanding and consequences of natural law develop over time, let me look at a couple of sources in chronological order, starting with Aristotle and arriving at the current, 1993 Catechism. Aristotle, in his Rhetoric points to a distinction between societal laws and laws that derive from nature and that supersede the conventions of a society. While doing so, he refers to examples from Greek literature that already at his time were “classics”:
“Universal law is the law of Nature. For there really is, as every one to some extent divines, a natural justice and injustice that is binding on all men, even on those who have no association or covenant with each other. It is this that Sophocles’ Antigone clearly means when she says that the burial of Polyneices was a just act in spite of the prohibition: she means that it was just by nature: “Not of to-day or yesterday it is, But lives eternal: none can date its birth.” And so Empedocles, when he bids us kill no living creature, says that doing this is not just for some people while unjust for others: “Nay, but, an all-embracing law, through the realms of the sky Unbroken it stretcheth, and over the earth’s immensity.””St. Augustine then emphasizes three very interesting things about natural law. First, that it relates to the orderedness of the universe (which is also its basis of intelligibility and of rationality in general):
“Therefore, let me explain briefly, as well as I can put it in words, the notion of that eternal law which is impressed upon our nature: ‘It is that law in virtue of which it is just that all things exist in perfect order.’” (De libero arbitrio, 1.8.18.)Second, that such ontological order translates to a rational one and that acting in accordance with it leads to a well-ordered and fulfilled life:
“From this ineffable and sublime arrangement of affairs, then, which is accomplished by divine providence, a natural law [naturalis lex] is, so to speak, inscribed upon the rational soul, so that in the very living out of this life and in their earthly activities people might hold to the tenor of such dispensations.” (De Diversis Questionibus Octoginta Tribus) “Whatever sets man above the beast, whether we call it ‘mind’ [mens] or ’spirit’ [spiritus] or, more correctly, both since we find both terms in Scriptures, if this rules over and commands the other parts that make up man, then man’s life is in perfect order ... We are to think of a man well-ordered, therefore, when his reason rules over these movements of the soul, for we must not speak of right order, of or order at all, when the more perfect is made subject to the less perfect ... It follows, therefore, that when reason, [ratio] or mind [mens], or spirit [spiritus], rules over the irrational movements of the soul, then that is in control in man which ought to be, by virtue of the law which we found to be eternal.” (De libero arbitrio, 1.8.18.)Here the idea of a right order seems particularly well aligned also with the first (and again last) step of the Buddha’s Eightfold Path, which is right understanding and about which he says that it is “a knowledge and vision of things as they really are”. Third, St. Augustine - rooted in St. Paul - is also very clear about natural law being accessible to all, regardless of their beliefs and he even goes as far as to recognize its knowledge in the “ungodly”:
“For who but God has written the law of nature (naturale legem) in the hearts of men? that law concerning which the apostle says: "For when the Gentiles, which have not the law, do by nature the things contained in the law, these, having not the law, are a law unto themselves: which show the work of the law written in their hearts, their conscience also bearing them witness and their thoughts the meanwhile accusing or else excusing one another, in the day when the Lord shall judge the secrets of men." [Rom. 2:14-16] And therefore, as in the case of every rational soul, which thinks and reasons, even though blinded by passion, we attribute whatever in its reasoning is true, not to itself but to the very light of truth by which, however faintly, it is according to its capacity illuminated, so as to perceive some measure of truth by its reasoning.” (Commentary on the Sermon on the Mount) “For hence it is that even the ungodly think of eternity, and rightly blame and rightly praise many things in the morals of men. And by what rules do they thus judge, except by those wherein they see how men ought to live, even though they themselves do not so live? And where do they see these rules? For they do not see them in their own [moral] nature; since no doubt these things are to be seen by the mind, and their minds are confessedly changeable, but these rules are seen as unchangeable by him who can see them at all; nor yet in the character of their own mind, since these rules are rules of righteousness, and their minds are confessedly unrighteous. Where indeed are these rules written, wherein even the unrighteous recognizes what is righteous, wherein he discerns that he ought to have what he himself has not? Where, then, are they written, unless in the book of that Light which is called Truth? Whence every righteous law is copied and transferred (not by migrating to it, but by being as it were impressed upon it) to the heart of the man that works righteousness; as the impression from a ring passes into the wax, yet does not leave the ring.” (De Trinitate, 14.15.21.)St. Augustine paints a picture of great harmony here: the universe is ordered, reason recognizes that order and even those who do not live in sync with it understand that there is an order that is proper to human conduct and that is inscribed in nature. Next, St. Thomas Aquinas develops the concept of natural law by thinking of it as a rational agent’s participation in God’s eternal reason:
“All things partake somewhat of the eternal law, insofar as, namely, from its being imprinted upon them, they derive their respective inclinations to their proper acts and ends. Now among all others, the rational creature is subject to divine providence in a more excellent way, insofar as it partakes of a share of providence, by being provident for itself and for others. Wherefore it has a share of the eternal reason, whereby it has a natural inclination to its proper act and end, and this participation of the eternal law in the rational creature is called the natural law.” (Summa q91, a2 (p20))Going beyond just the concept of Natural Law, Thomas Aquinas takes a stab at spelling out its “first principles” as being the following: that good is to be done and pursued, and evil is to be avoided, that life is to be preserved, that one is to reproduce and raise one’s offspring and that knowledge and life in society are to be pursued:
“Whatever the practical reason naturally apprehends as man’s good (or evil) belongs to the precepts of natural law as something to be done or avoided. [...] All those things to which man has a natural inclination are naturally apprehended by reason as being good and, consequently, as objects of pursuit, and their contraries as evil and objects of avoidance. [...] Wherefore the order of the precepts of the natural law is according to the order of natural inclinations."What is interesting here is that, in addition to the orderedness of reality being reflected in our understanding of it that St. Augustine spoke of, St. Thomas adds to it also a link to our inclinations, making being, understanding and desire all aligned with each other. Even though St. Thomas already speaks about limits to the understanding of natural law, and gives examples of it being overridden in some societies (e. g., “theft, although it is expressly contrary to the natural law, was not considered wrong among the Germans, as Julius Caesar relates.”), the overall picture is one of all-encompassing harmony. In 1888 Pope Leo XIII picks up the subject of natural law in the context of his encyclical entitled Libertas (“freedom”). There he first challenges the notion of freedom being opposed to an adherence to laws, which he in turn equates with reason:
“Nothing more foolish can be uttered or conceived than the notion that, because man is free by nature, he is therefore exempt from law. Were this the case, it would follow that to become free we must be deprived of reason; whereas the truth is that we are bound to submit to law precisely because we are free by our very nature.”Leo XIII then defines natural law as follows, identifying it again with reason:
“natural law [...] is written and engraved in the mind of every man; and this is nothing but our reason, commanding us to do right and forbidding sin.”and proceeds to elaborate on how God helps us to adhere to it in a way that does not cancel our freedom:
“To this rule of action and restraint of evil God has vouchsafed to give special and most suitable aids for strengthening and ordering the human will. The first and most excellent of these is the power of His divine grace, whereby the mind can be enlightened and the will wholesomely invigorated and moved to the constant pursuit of moral good, so that the use of our inborn liberty becomes at once less difficult and less dangerous. Not that the divine assistance hinders in any way the free movement of our will; just the contrary, for grace works inwardly in man and in harmony with his natural inclinations, since it flows from the very Creator of his mind and will, by whom all things are moved in conformity with their nature.”The need for help with discerning natural law is also underlined in Pope Pius XII’s 1950 encyclical Humani Generis, where he writes:
“[T]he human intellect, in gaining the knowledge of such truths is hampered both by the activity of the senses and the imagination, and by evil passions arising from original sin. Hence men easily persuade themselves in such matters that what they do not wish to believe is false or at least doubtful.”And with that we arrive at the Church’s present understanding of natural law, which is clearly set out in the current Catechism. There human rationality (which already to St. Augustine was key) is presented as the interface with the natural law [note also the referring to humans as animals, consistent with evolutionary continuity]:
“Alone among all animate beings, man can boast of having been counted worthy to receive a law from God: as an animal endowed with reason, capable of understanding and discernment, he is to govern his conduct by using his freedom and reason, in obedience to the One who has entrusted everything to him.” (§1951) “Man participates in the wisdom and goodness of the Creator who gives him mastery over his acts and the ability to govern himself with a view to the true and the good. The natural law expresses the original moral sense which enables man to discern by reason the good and the evil, the truth and the lie.” (§1954)The aims of natural law, it’s subsisting in reason and being accessible universally are spelled out next:
“The natural law states the first and essential precepts which govern the moral life. It hinges upon the desire for God and submission to him, who is the source and judge of all that is good, as well as upon the sense that the other is one’s equal. Its principal precepts are expressed in the Decalogue. This law is called “natural,” not in reference to the nature of irrational beings, but because reason which decrees it properly belongs to human nature. [...] The natural law is nothing other than the light of understanding placed in us by God; through it we know what we must do and what we must avoid. God has given this light or law at the creation.” (§1955) “The natural law, present in the heart of each man and established by reason, is universal in its precepts and its authority extends to all men. It expresses the dignity of the person and determines the basis for his fundamental rights and duties.” (§1956)The Catechism then picks up on St. Thomas Aquinas’ point about variation in the application of natural law and presents a particularly useful way of looking at how our varying understanding of natural law differs from the immutable natural law itself (a relationship akin to that between science and the laws of nature):
“Application of the natural law varies greatly; it can demand reflection that takes account of various conditions of life according to places, times, and circumstances. Nevertheless, in the diversity of cultures, the natural law remains as a rule that binds men among themselves and imposes on them, beyond the inevitable differences, common principles.” (§1957) “The natural law is immutable and permanent throughout the variations of history; it subsists under the flux of ideas and customs and supports their progress. The rules that express it remain substantially valid. Even when it is rejected in its very principles, it cannot be destroyed or removed from the heart of man. It always rises again in the life of individuals and societies.” (§1958)While the Christian sources cited so far all speak about a close link between natural law and divine law, the vast majority of what they assert about it can, in my opinion, be considered even in the absence of theist beliefs and depends only on whether moral values can be discerned by reason or whether they are all solely the result of social convention or individual choice. E.g., whether the goodness of treating men and women equally can be arrived at by the use of reason alone or whether it is solely the result of a social contract. Whether we could all just agree on its opposite tomorrow or whether the rational appeal of it would persist against social consensus. This is a question that has been controversial for centuries and I won’t even attempt to do it justice here, skipping even Hume’s famous distinction between is and ought (i.e., that what is (e.g., as in human nature) has no normative power), and I’ll just conclude with presenting a pair of opposite assessments of natural law from the atheist perspective. The first is Mark Murphy’s flat-out declaration of their incompatibility in the Stanford Encyclopedia of Philosophy:
“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.”To me this sounds a bit tautological though in that it can be read as saying: the way St. Thomas Aquinas speaks about natural law is theist, therefore there is no atheist way of positing natural law. It does not engage with considering whether those aspects of Aquinas’ thought on natural law that are not theist (i.e., “human’s-eye point of view”) don’t also make sense in isolation (and would argue that they do). Second, Murray Rothbard’s rebuttal of such a facile opposition to the concept of human nature in atheist thought, arguing precisely from a perspective of humans being just as much part of the material world as atoms, molecules and stones, all of which have specific shared features.
“It is indeed puzzling that so many modern philosophers should sniff at the very term "nature" as an injection of mysticism and the supernatural. An apple, let fall, will drop to the ground; this we all observe and acknowledge to be in the nature of the apple (as well as the world in general). Two atoms of hydrogen combined with one of oxygen will yield one molecule of water — behavior that is uniquely in the nature of hydrogen, oxygen, and water. There is nothing arcane or mystical about such observations. Why then cavil at the concept of "nature"? [...] And yet, if apples and stones and roses each have their specific natures, is man the only entity, the only being, that cannot have one? And if man does have a nature, why cannot it too be open to rational observation and reflection? If all things have natures, then surely man’s nature is open to inspection; the current brusque rejection of the concept of the nature of man is therefore arbitrary and a priori.”Considering all of the above, I believe there is a basis for recognizing that humans have rational access to innate moral values, from which normative laws can be derived. This does not necessitate a belief in a superhuman source of such laws (although for a Christian such a belief has added incentives for discernment and adherence) or a belief that those laws are perfectly and unchangeably known. In fact, the Church too recognizes that the natural law is not immediately accessible and that it subsists beneath our attempts to elucidate it, attempts that because of this alone need to continue and may yield evolving results. All that a subscription to the concept of natural law entails is a belief to there being values that derive from who humans are rather that only from our arbitrary consensus.