The Clarity and Specificity of Thomistic Natural Law

Natural law theory has had a long and honorable history – from ancient Greek philosophy to the Stoics, St. Thomas Aquinas and other scholastics, as well as Protestant “natural lawyers” such as Grotius, Cumberland, and Pufendorf.

In the last few centuries, however, an immense amount of opposition to natural law has emerged from ethicists. Jeremy Bentham (1748-1832) complained that appeals to “natural law” were simply camouflaged personal sentiments, and developed his own theory, utilitarianism, as an external gauge that would offer objective moral criteria.

Immanuel Kant (1724-1804) faulted natural law for its lack of authoritativeness, and offered his own procedure for testing for “universal” norms, the “Categorical Imperative,” as a sure guide for rational certainty in moral matters. 

In the latter half of the twentieth century, John Finnis, Germain Grisez, and others have proposed a “new natural law” theory, which is based on seven “self-evident” rational values.

Stephen Buckle in Companion to Ethics (1991) sums up what he considers to be the main problem with natural law: namely, the presupposition that we cannot know enough about human nature to derive moral norms.

More recently, some Catholic magazines have joined the fray in opposition to natural law. The magazine First Things (December 2009) published Paul Griffiths’ “The Nature of Desire,” which argued that the unrealizable “infinity” of human desires depicted by Shakespeare and other artists makes it impossible to portray any human inclinations in terms of a “natural law.”

And in June, 2012, The New Oxford Review published Melinda Selmys’ “Is the Natural Law Obsolete,” which claims that natural law is a “dead letter” unless it is forcefully bolstered with appeals to aesthetics.

A common denominator in the articles by Griffith and Selmys is a complete lack of reference to any natural law theory, except for a single indirect reference by Selmys to Aquinas’ theory. I and others wrote critical letters, which were published a few months later by both magazines, but the authors’ replies to these letters still showed hardly any familiarity with, or interest in, natural law theory.

If we equate natural law merely with what Aquinas calls the “first principle” of natural law – i.e., good is to be done, evil is to be avoided – the world understandably. . .yawns, and goes on its merry way.

But, as Aquinas argues, this apparently single principle of natural law becomes threefold, if we take into account the ontological aspect of natural inclinations. The three “precepts” of the natural law that follow from this basic principle are what give “teeth” and specificity to the natural law, and rescue it from being the merely vague and abstract idea of “conformity to nature,” which elicits dismissal by critics.

          The Triumph of Aquinas (detail, with Aristotle, Plato, and Averroes) by Benozo Gozzoli, c. 1480

A specific characteristic of these precepts, as I argue in my book, Natural Law: an Introduction and Reexamination, is that they are also natural rights; this differentiates them from the multitude of idiosyncratic inclinations that cannot be claimed as universal laws or rights.

A triad of laws/rights follows from an analysis of basic human inclinations: 

1.         The law of self-preservation; which is also the right of self-preservation, and which implies a reciprocity among humans respecting the right to exist. Specific applications of the first precept follow clearly: duties to protect one’s life, not risk life unnecessarily, not commit suicide, work to acquire the property necessary for sustenance, and recognize others’ right to life and property.
2.         The duty to procreate and care for progeny – a care that, because human animals require much more time than other animals to mature, can be required for many years. Obviously included in this precept is the nurturing of infants and children, the teaching of skills for their continuance and success in life, etc. Likewise included is the right of procreation (not “reproductive rights,” the current euphemism for abortion), which is infringed by governmental measures like China’s “one-child” policy. (Aquinas explains that procreation is a duty for the human race as a whole, but not for each individual; so a person may decide to remain single, or may even embrace celibacy in a religious order.)
3.         The third precept is connected with rationality itself: the duty of rational beings in the intellectual/theoretical sphere to seek the truth, and in the practical sphere to work for a rational ordering of society. Clearly this implies a duty and right to educate oneself, and for society to strive to provide the necessary implements for education. Also, it clearly rules out ideological prohibitions that restrict access to the truth, or withhold facts necessary for making rational decisions. One might also add, it implies the duty/right of news media to present “the whole news,” not a truncated, biased version.

The examples I have just mentioned seem to follow without too much ratiocination from the three Thomistic precepts. Aquinas admits, however, that there are some “secondary” applications that may not be clear in some environments or circumstances. He gives examples of cases where different ideas of property rights may seem to legitimize stealing, or where ignorance of normal sexuality may lead to sodomy.

We might add the following extra possibilities of mistaken “secondary applications” caused by circumstantial ignorance:

  • The incredible ignorance of mothers who really think they are just destroying something like a parasite, not a human being, in abortion;
  • the ignorance of users of contraceptive pills who, making use of the complex chemical mechanisms, really think they are doing something virtuous, even helping to combat “overpopulation”;
  • the ignorance of educators who really think they are helping civil society by introducing children to information about all kind of anomalous sexual practices.

But certainly, for most normal rational beings, it should not be very difficult to deduce some very concrete applications from the three precepts of natural law: the law/right of self-preservation; the law/right of “increasing and multiplying”; and the law/right of seeking the truth and combating error both in the intellectual and the practical spheres.


Howard Kainz

Howard Kainz

Howard Kainz, Emeritus Professor at Marquette University, is the author of twenty-five books on German philosophy, ethics, political philosophy, and religion, and over a hundred articles in scholarly journals, print magazines, online magazines, and op-eds. He was a recipient of an NEH fellowship for 1977-8, and Fulbright fellowships in Germany for 1980-1 and 1987-8. His website is at Marquette University.

  • Eric Giunta

    This would have been a better piece if Dr Kainz bothered to explain just how those secondary principles follow from the first.

  • Jack,CT

    Great Article,Thanks..

  • Dave

    Thank you, Dr. Kainz. The great scandal of our age is that people think the power and the right to choose is the defining characteristic of freedom, without regard to the moral content or purpose of the choices. The corollary is that the lack of ability to choose, which translates to an absence of “personhood,” by means of which absence abortion and euthanasia — and other ills yet to come — become not only permissible but “good,” insofar as the elimination of inconveniences expands the practical scope of one’s power to choose other things. Each and all of the Thomistic premises have a teleology; current doctrines, if they be called such, do not, insofar as they are oriented to the maximization of current pleasures, however they be defined. Let us hope and pray that in this Year of Faith we recover for ourselves and for our societies the foundational truths not only of natural law, but that each and every soul is created in the image and likeness of God, and that therefore each and every person, regardless of his or her “capacity,” shows us something of God and therefore has both a right to exist and a purpose for it.

  • Other Joe

    Words contain seeds of implication. Can moral necessity flow from objects and their relationships, or must moral necessity flow from persons and their relationships? The Enlightenment philosophes put their money on objects, which they imagined to be small, hard building blocks of all that can be experienced. As physicists peer ever deeper into the weirdness of quantum events they find there is no “there” there. The hard little bits are shadows. As geneticists peer ever deeper into cellular activity, they keep encountering ever more complex “programming” which bespeaks of intent. The term Natural Law carries within the term associations with objectivism or naturalism. The signers of our nation’s founding documents were men attuned to the Enlightenment. But at least they were not completely objectivists. They understood that objects were created by intention – something many moderns have forgotten.

  • Martha Rice Martini

    Here’s the problem. Natural law for St. Thomas means obedience to the Ten Commandments and is fairly (and by him, expressly) grounded in Scripture. See Romans 2:14. Natural law as “developed” by moderns like Jacques Maritain (The Rights of Man and Natural Law) means a vast web of entitlement claims against the state. Maritain’s understanding was adopted practically wholesale by the United Nations in 1948 (Maritain was one of the drafters of The Universal Declaration of Human Rights) and subsequently (again, through Maritain’s influence) by the Church. See Pacem in Terris. But whether Maritain’s “development” of natural law is fairly rooted in St. Thomas (ST I-II 94.2) is a large and unanswered question. What’s undeniable is that Maritain’s understanding has captured the Church.

  • Manfred

    Thank you for your scholarship, Howard. Unfortunately, the world has passed sentiments of this nature by. Tonight the Cdl. Abp. of New York/president of the USCCB will host Barack Hussein Obama at the Al Smith Dinner. Pres. Obama stands for abortion, infanticide, aberrosexual marriage and having HHS,led by catholic Sebelius, bully the Catholic Church. In the schizophrenic Church there are some who insist that NO practicing Catholic could vote for him. Yet Cdl Dolan will be there in his Halloween suit (I am sorry, but when he wears scarlet the martyr significance is completely lost) with his arm around Obama cracking jokes and sharing stories with him and Romney. Just another day in the office in a tightly run and expensive presidential campaign just days before the election. Can anyone name an offense that would prohibit a person from being invited to the Dinner? An anti-semitic slur? Use of the “N” word? Use of the “L” word? Public nudity? We are still trying to connect the words “Nature” and “Law”?

  • Titus

    “Natural law for St. Thomas means obedience to the Ten Commandments”

    St. Thomas does not posit that the Natural Law is made up merely of the Decalogue. The Ten Commandments are Divine Law, which articulate the content of the Natural Law, but Natural Law, and knowledge of it, does not depend upon the promulgation of these or other specific commands.

    “This would have been a better piece if Dr Kainz bothered to explain just how those secondary principles follow from the first.”

    Space limits exist even in cyberspace. I imagine one could find this out by reading the book.

  • Howard Kainz

    @Martha Rice Martini: The last seven of the Ten Commandments, as St. Paul says in Romans, are contained in the natural law. But the natural law, as St. Thomas develops the philosophical implications, goes beyond the Decalogue. Arguably the most important natural law for rational beings, as St. Thomas says, is to seek the truth in the theoretical and practical orders. This is adumbrated a bit in the eighth commandment, but Aquinas brings it out more explicitly.

  • Athanasius

    Manfred, you are a good person and I enjoy many of your insights. But I believe you are mistaking Cardinal Dolan’s invitation to Barack Obama as an implicit approval of his policies. I do not think this is the case. The Al Smith dinner has a tradition of inviting both presidential candidates. Since both will disagree on the issues, inviting both cannot logically imply approval of all positions of both. Anyone familiar with this dinner would not be confused by this, so it is not scandalous.

    Rather, I believe Cardinal Dolan is trying to keep the lines of communication open so that he can truly dialogue with members of both parties. Didn’t our Lord eat dinner with sinners in hopes of enlightening them? Nothing Cardinal Dolan has said or written implies agreement with Obama’s radical positions. Quite the opposite. But shouldn’t we as Christians care for Obama’s soul? You and I can only pray for him, but Cardinal Dolan can use his seat to actually dialogue with him. Will it work? Only God knows. But I believe part of the virtue of hope is for us to try.

  • Manfred

    Athanasius: The plot thickens! Jack Fowler of National Review Online asserts that Messrs. Robert Wright, John Zuccotti, Peter Kiernan III and AL SMITH IV, the chairman of the Dinner foundation, are well-heeled supporters of pro-abortion Democratic lawmakers. That clears it up doesn’t it?
    Catholic Charities stand to gain $5 million TONIGHT. Abortion? Infanticide? Aberrosexual marriage? the Archdiocesan lawsuit against HHS? Who remembers?
    Thank you for your thoughtful comments.

  • Sue

    Thank you Manfred for that article reference. Al Smith IV is a perfect example of why we haven’t even started to talk about the intrinsic evil conflicts of Romney. And further proof that USCCB is to be treated as authoritative as the Chinese govt puppet Patriotic Church.

  • Jack,CT

    Dear Friend:
    I feel Athanasius” is correct.We can “keep
    the peace” and still disagree.

  • DS

    Athanasius, could not agree with you more. Easy to sit at a keyboard and condemn the President,, condemn (and insult) the Cardinal, condemn the USCCB, condemn the quality of the US episcopate, condemn Vatican II…..Much harder to do what Christ calls us to do: follow him and make disciples. That requires conversion. Conversion requires engagement with adversaries/enemies, prayer for them, hard work and patience. Perhaps discerning the root causes of “circumstantial ignorance.” And one can do all of this without compromising faith or principle. It seems to me that Cardinal Dolan is about as faithful as they come.

  • Sue

    It is not easy to criticise the Cardinal, it goes very much against the grain. (It is necessary, though I don’t advocate insulting him.) That difficulty is what has protected the USCCB over the past many decades – the reluctance of ordinary Catholics to call out fifth column Marxists in USCCB from dismantling the Church in America. (Note I am not saying Cdl Dolan is such a Marxist but he may be an unwitting tool of them in his position as head of USCCB. It would subtract nothing from his ministry to implode USCCB and, simply, bishop his own archdiocese).

    The tenor of most Al Smith supporters appears no different than those supporting Notre Dame in its honoring of Obama. “Conversion requires engagement” platitudes ring very familiar. Could be lines from a speech by Fr. Hesburgh of Notre Dame (also pres. of Rockefeller Foundation btw) or Cardinal Bernardin, head of bishops’ conference from way back. Or are they also to remain above reproach?

  • ib

    Let’s just make one thing clear here: In Roman Catholic teaching the Bishops are the successors to the Apostles. They alone have authority in the RC Church given to them by Jesus Christ. As the Catechism says: “The task of giving an authentic interpretation of the Word of God, whether in its written form or in the form of Tradition, has been entrusted to the living, teaching office of the Church alone. Its authority in this matter is exercised in the name of Jesus Christ. This means that the task of interpretation has been entrusted to the bishops in communion with the successor of Peter, the Bishop of Rome” (CCC II.I.III.).

    Here’s some facts: the USCCB is in communion with the successor of St Peter. So it is one means that the Bishops have to teach in all of the dioceses within its territory. And it IS authoritative within clearly established limits. As Pope John Paul II wrote in Apostolous Suos,
    “The Code of Canon Law establishes the fundamental norm in this regard: ‘Although they do not enjoy infallible teaching authority, the Bishops in communion with the head and members of the college, whether as individuals or gathered in Conferences of Bishops or in particular councils, are authentic teachers and instructors of the faith for the faithful entrusted to their care; the faithful must adhere to the authentic teaching of their own Bishops with a sense of religious respect (religioso animi obsequio)’.(79)

    To treat a Bishop (or Bishops) as if they were simply churchy bureaucrats is to adopt a fundamentally Protestant attitude. It is ironic that several commentators on this site, posing as “truest of the true Catholics” adopt the most pedestrian Protestantism much of the time to blast away at the Bishops. They should know that at best they are making what in philosophy is known as a “category mistake” and at worst are acting as vermin, chewing away at the foundations of the Holy Roman Catholic Church established by Jesus Christ and entrusted to the Apostles and their successors.

    If you don’t like the Roman Catholic Church in all its reality, do us a favor: don’t play the role of modern-day-Luther, just leave.

  • Ib

    His Eminence Cardinal Dolan cannot “implode” the Bishops Conference in the U.S. He does not have the authority to do that. Here’s another quote from John Paul II’s moto proprio “Apostolous Sous” for all those who remain ignorant of real Roman Catholic teaching (but are full of their own opinion, as true Protestants):

    5. In 1966, Pope Paul VI, by the Motu Proprio Ecclesiae Sanctae, called for Episcopal Conferences to be established wherever they did not yet exist; those already existing were to draw up proper statutes; and in cases where it was not possible to establish a Conference, the Bishops in question were to join already existing Episcopal Conferences; Episcopal Conferences comprising several nations or even international Episcopal Conferences could be established.(30) Several years later, in 1973, the Pastoral Directory for Bishops stated once again that “the Episcopal Conference is established as a contemporary means of contributing in a varied and fruitful way to the practice of collegiality. These Conferences admirably help to foster a spirit of communion with the Universal Church and among the different local Churches.(31) Finally, the Code of Canon Law, promulgated by me on January 25, 1983, established specific norms (Canons 447-459) regulating the objectives and the powers of Episcopal Conferences, as well as their erection, membership and functioning.

    Now get along you shadow-Protestants. Go start your own faith … Just stop calling yourselves Roman Catholics if you don’t really accept the teachings of the RC Church.

  • Sue

    Thank you for referencing Apostolos Suos (AS), but it reads differently when you see it in detail.

    “His actions are strictly personal, not collegial, even when he has a sense of being in communion.” AS II.10

    “At the level of particular Churches grouped together by geographic areas (by countries, regions, etc.), the Bishops in charge do not exercise pastoral care jointly with collegial acts equal to those of the College of Bishops.” AS II.10

    “In fact, only the faithful entrusted to the pastoral care of a particular Bishop are required to accept his judgement given in the name of Christ in matters of faith and morals, and to adhere to it with a religious assent of soul.” AS II.11

    “Nonetheless, this territorially based exercise of the episcopal ministry never takes on the collegial nature proper to the actions of the order of Bishops as such, which alone holds the supreme power over the whole Church. In fact, the relationship between individual Bishops and the College of Bishops is quite different from their relationship to the bodies set up for the above-mentioned joint exercise of certain pastoral tasks.” AS II.12

    I stand with the Pope and my bishop and fully accept the Church’s teachings. It is my understanding that I am not required to conflate USCCB with the Church.

  • G.K. Thursday

    Wonderful article defending the natural law. We need more of these.

    I read Griffith’s article in FT 2009, and as I recall it was pretty much eviscerated by the critics (of which Dr. Kainz was one). I did not read the Selmys’ artcle since I stopped reading NOR back in the 90s when it had degenerated into a haven for sede-vacantists and others along that line. Has it now become a left-leaning magazine? Gone from one extreme to the other? More’s the pity.

  • G.K. Thursday

    Great post!

  • George Sim Johnston

    Pope Benedict XVI points out that the phrase “God said” occurs ten times in the creation account in Genesis, and that the Ten Commandments–the Decalogue, the “ten words”–may be considered as an “echo of creation”. In other words, they state truths that are built into the human person. I like the classical definition of natural law as the rational person’s participation in divine law by which God moves all things toward their appointed end.

  • ib


    As a famous guy once said, “there you go again.”

    It’s probably of little use to point out that only you bring up the idea of conflating the USCCB with anything. It is not the point of the Catechism passage quoted, nor “Apostolous Suos”, nor the Code of Canon Law. It is your own idea, and no-one else’s.

    The USCCB is not the Church, nor is it the College of Bishops. Nor is it anything else but itself. It is a canonical edifice established by the authority of the Code of Canon Law, and given approval by the Pope (that’s why Cardinal Dolan has no authority over its existence). “Apostolous Suos” is very clear on the limits of the authority of a Bishops Conference, stipulating that only when it acts unanimously and in agreement with the Pope does it have teaching authority (AS 22). But when it does so, it teaches with authority. If you don’t like that Sue, then you don’t stand with either the Popes or your Bishop, since they both hold this under Canon Law. Moreover this motu proprio is more than a bureaucratic notice: it has binding force in Canon Law, first and foremost on the Bishops, but also on you as a subject of your Bishop.

    So go ahead and bash the USCCB, but know that it is canonically established and Papally-approved, and has genuine teaching authority within its narrow limits. I suggest that you have a chat sometime with a canon lawyer to become familiar with the wonderful reality of Roman Catholic Church Law. If you’re like most folks, you probably have never even opened the Code, let alone studied it.

  • G.K. Thursday

    I also meant to remark on the wonderful painting by Gozzoli! Where did you find it?

  • Sue


    And I quote from Avery Cardinal Dulles, First Things, Feb. 2006 “From Ratzinger to Benedict”:

    “Bishops who are assigned to dioceses participate in the direction of the universal Church by governing their own churches well, keeping them in communion with the Church Catholic. The synod of bishops, in Ratzinger’s later theology, is no longer seen as a collegial organ or as a council in miniature; it is advisory to the pope as he performs his task. In so doing it makes the voice of the universal Church more clearly audible in the world of our day.

    A similar shift is apparent in Ratzinger’s view of episcopal conferences, which he had earlier characterized as collegial organs with a true theological basis. But by 1986 he says: “We must not forget that the episcopal conferences have no theological basis; they do not belong to the structure of the Church as willed by Christ, that cannot be eliminated; they have only a practical, concrete function.” It is difficult to deny that on episcopal conferences, as on the synod of bishops, the cardinal retracted his earlier positions.”


    The Diocese of Lincoln wrote the following on 9/2/2011, “Bishops and Priests”, in its Southern Nebraska Register:

    “In his 1986 book, “The Ratzinger Report”, (published by Ignatius Press), the future Pope Benedict XVI spoke to the journalist, Vittorio Messori, at some length about what he saw as certain drawbacks deriving from excessive and exaggerated importance sometimes being attributed to national or regional Bishops’ Conferences and to their undertakings. He said, for instance, “It happens that with some Bishops there is a certain lack of a sense of individual responsibility, and the delegation of his inalienable powers as shepherd and teacher to the structures of the local (Bishops’) conference leads to letting what should remain very personal lapse into anonymity. The group of Bishops united in the conferences depends in their decisions upon other groups, as for example, upon commissions (committees) that have been established to prepare draft proposals. It happens then that the search for agreement between different tendencies and the effort at mediation often yield flattened documents in which decisive positions, where they might be necessary, are weakened.”

    He then gave an example from the 1930’s in his native country of Germany. “Well, the really powerful documents against National Socialism (the Nazi doctrines) were those that came from individual courageous Bishops. The documents of the (Bishops’) Conference, on the contrary, were often rather wan and too weak with respect to what the tragedy called for.”

    As I say, I stand with the pope.

  • Jacob r

    Most people in academia are not very naturally intelligent so maybe that’s why they hate natural law.
    But seriously I’ve noticed that these academics, philosophers especially, are indistinguishable from MBAs.
    It’s the same Darwinistic death match for that number one spot and all the prizes: people caring at all what you have to say, overpaid tenure positions, jet setting with the international elite, etc.
    It’s strange to me how, like with judges, humanity pretends these people are above base human behavior (like attacking something you know nothing about, because you’ve located it with the one extraordinary skill you have: determining how to gain the most by manufacturing that next exciting and self reassuring intellectual controversy leftist academia is dying for).