Published in The Jurist 68 (2008) 569-591

Lex naturalis and Ius naturale

Ken Pennington

After the air attacks of September 11, 2001 the United States government decided to fortify all public government buildings and spaces of importance in Washington, D.C. that might be targets of future attacks.  The expenditures for these projects ran to millions of dollars and included the White House, Congress, and the Supreme Court.  These extensive fortifications were inspired by widespread fear in all levels of the American government that extreme measures were needed to protect themselves and government buildings.  This culture of fear quickly became an accepted part of American political discourse.  Fear was no longer cowardly; it became a badge of courage.  Streets around government buildings were closed.  Streets that remained open were provided with retractable barriers. A security cordon around the White House was greatly expanded.  The public was denied entrance to the grand staircase on the West side of the Capitol buildings.  Armed police were placed on every corner of Capitol Hill twenty-four hours a day.  To secure perimeters metal bollards were placed around buildings and public spaces at a cost of $10,000 each. They could not protect against air attacks or suicide bombers ― only truck and car bombs ― but that fact did not deter the frenzy of construction that still continues.  Thousands of bollards were put in place. The directors of every government agency stumbled over one another to arrange that their spaces be surrounded by these symbols of fear.  The question that every director in Washington must have asked themselves again and again was “How could their  buildings be bereft of these symbols that made a public statement of their  importance?”  Even the coal burning steam plant on Capitol Hill ― the worst source of pollution in Washington ― was fortified.[1]  The bollards around the Supreme Court were the only ones decorated with a Latin word: Lex.  Why did the judges choose lex and not ius for those protective fences? 

To answer that question we have to go back to the Renaissance of law in the twelfth century.  Ius and lex were terms of Roman law.  The first jurist to examine lex and ius in detail was named Gratian who taught canon law in Bologna.  In the first half of the twelfth century he compiled a Tractatus de legibus with which he introduced his students to law.  He became the first jurist in the European tradition to explore the meanings of ius and lex.   Gratian introduced his Tractatus with a statement that would remain a standard statement for centuries:[2]

The Human Race is ruled by two things:  namely, natural ius and  mos.  The ius of nature is what is contained in the lex and the Gospel.  By it, each person is commanded to do to others what he wants done to himself and is prohibited from inflicting on others what he does not want done to himself.  This indeed is the lex and the prophets.

Gratian recognized two major elements of human law:  ius and mos.  He connected ius with natural law and lex with the Old and New Testaments.  Human lex did not enter into his discussion ― yet.  To understand Gratian’s awkward introduction one must remember that legislative institutions were just beginning to appear in twelfth century society; custom regulated society not leges.  If Gratian had written his introduction a century later he very likely might have written: “Humanum genus duobus regitur, naturali uidelicet et positivo iure.”[3]  But the canonists had not yet invented the term “ius positivum.” To define “ius naturae” he relied on Matthew 7:12.  Ius commands each person to render onto others what each person would want others to render onto her ― the Golden Rule.

            Gratian patterned his thought after texts that he found in Justinian’s Digest.  There he found a statement by the ancient jurist Gaius who also defined the law that governed human society:[4]

All peoples who are ruled by lex and mos  partly use their own ius and partly the ius that is common to all men.  The ius that each nation has constituted for itself  for each city is called the ius civile; almost as if  it were a ius proprium of that city.  What, however, the natural reason of men establish and is used by all men equally, is called the ius gentium, almost as if all human beings use that ius.

Gaius began with lex but quickly switched his terminology to ius.  Ius can be common to all men, but ius also governs each city.  This ius proprium is also called ius civile.  The ius gentium that is common to all men is established by human reason.  Gaius’ statement is followed by a excerpt from Ulpian, which was the Roman version of the Golden Rule and gives another meaning to ius:[5]  “Justice is the constant and perpetual will of giving everyone their Ius.” Ulpian implicitly pointed out that ius also means right and that justice can be defined by rendering everyone their proper rights.   He continued by observing that there were three principles of ius, to live honestly, to not injure other people, and to render everyone their ius.[6] 

            The Roman jurist Paul discussed the equivocal meanings of ius immediately after Ulpian’s text:[7]

The term “ius” can be used in several ways.  In one way “ius” means what is always equitable and good, as “Ius naturale”. In another way  what is in the interest of all or of many in a state (civitas), such as the “Ius civile”  .  .  . Yet another meaning of “ius” is to describe the place in which “ius” is vindicated, the name having been given by him who renders “ius” on the place where he does it.  We can know where that place is  by wherever the praetor decides to exercise his jurisdiction, preserving the majesty of his authority and respecting the ‘mos” of our ancestors.  That place is correctly called “ius.”

Paul’s definition is interesting for two reasons.  First, he gave ius a meaning that connects it with equity and equity’s handmaiden justice.  Second, he calls upon a very old tradition in Roman law that defined ius as the place where justice was rendered.[8]

            Gratian and the jurists had these texts of Roman law to draw upon for their ideas about ius and lex, but Gratian exploited another source, Isidore of Seville’s Etymologies for much of his thinking about the two terms.  Isidore discussed law in book five of great encyclopedia, but his ideas about law did not enter into the Western tradition until Gratian.  He incorporated a text of Isidore in which a contrast was drawn between, ius, mos, and lex:[9]

Consuetudo is a sort of ius established by mos and recognized as lex when lex is lacking.  It does not matter whether it is confirmed by writing or by reason, since reason also supports lex.  Furthermore, if lex is determined by reason, then lex will be all that reason has already confirmed --- all, at least, that is congruent with religion, consistent with discipline, and helpful for salvation.  Consuetudo is so called because it is in common use.

Custom was related to ius when grounded in mos and could be recognized as lex when there is no lex.  Reason was the fundamental core principle of custom and lex.  Early glossators on Gratian’s Decretum were careful to point out that custom did not have to be in writing, but lex was lex because it was written.  Gratian underlined the written character of lex by citing Isidore in the only place in his Tractatus where he offered a definition of lex:  Lex is a species of ius; lex is a written constitution.  Fifty years later Huguccio, the greatest canonist of the age, commented:[10]

Lex commands what is just and prohibits the contrary.  Lex is so named because it binds, or because it is read as writing, or because it legitimately functions by rewarding those who observe it and punishes those who transgress its rules.

At the end of the twelfth century the Roman jurist Azo expanded on the meaning of lex in his Summa on Justinian’s Codex:[11]

Lex is sometimes defined narrowly and sometimes broadly.  An example of a narrow definition is when a statute of the Roman people is called a lex  .  .  . A lex is the common opinion of men who are learned in the law .  .  . Lex is broadly defined when it is used to describe all reasonable statutes.  Whence lex is a sacred command, ordering honesty and prohibiting the contrary.  Consequently it is the rule that governs just and unjust people.

It is important to notice that the jurists never attributed the rich penumbras[12] of meanings to lex that they did to ius.  Lex was a plebian hod carrier of the law; ius was a term rich in resonances.  Ius reminded the jurists constantly of the transcendental significance of a legal system.  It existed not just to establish right and wrong and to punish the wicked.  It was the source of justice, equity, and rights.

            The jurists created a penumbra for lex that was not concentrated only on what was reasonable but also on consent.  Gratian was the first jurist in the European tradition who connected lex and consent.  In a famous passage he declared that leges are established when they are promulgated, but that they are valid when they are approved by the mos of those who use the leges.[13]    In contrast, from early on, the penumbras of ius were justice, equity, and the common good.  An anonymous jurist in the early twelfth century graphically illustrates this point.  In a gloss to Justinian’s Codex he described the relationship between ius and justice:[14]

Justice and ius are in effect the same or ought to be the same.  Whatever justice wants, ius strives to follow.  It happens that sometimes .  .  . ius is not in concord with justice.  When this occurs justice or equity interprets that, if ius openly departs from equity, we may ignore the authority of ius and follow equity.

Equity and justice belong in the realm of ius; no jurist would have thought about lex in the same way.  This fact is illustrated by the way in which the jurists talked about the hierarchy of laws.  They talked about ius divinum, ius naturale, and ius gentium.  These were not leges; they were iura.

            For the later jurists Ulpian’s and Gratian’s definition of justice dominated their thought.  Justice was the will to respect the ius of others.  It was a platitude in the legal tradition.  The platitude led them to consider other definitions that did not focus on ius.  The most prevalent of these was a definition of justice that focused on a social contract.  The idea that justice must not only be connected with ius/rights but also with the common good can be traced back to Cicero.  Many Christian thinkers followed this stoical line of thought.[15]  However, as we have seen, the ancient Roman jurists did not connect either justice or ius with the common good.  That changed in the twelfth century.  One of the first jurists to write a gloss on Gratian’s introductory definition of law and ius naturale, Paucapalea, undoubtedly influenced by theological thought, defined Gratian’s “each person is commanded to do to others what he wants done to himself and is prohibited from inflicting on others what he does not want done to himself” as justice.  And “justice,” he went on, “is the tacit contract of nature discovered to help many people.”[16] Early glosses to the Decretum repeated Paucapalea’s connection of ius naturale and justice.[17]   Abelard seems to have been one of the first theologians to make the connection between justice and the common good.  Referring to the theological and the legal traditions, he declared:[18]

The philosophers define justice as the “habitus” of the mind to render to every person what is his as long as the common good is preserved.[19] Justinian defined this concept in his definition when he would say, “Justice is the constant and perpetual will,”etc.   “His” can refer to the receiver as well as to the giver.  If it refers to the receiver then <his right> ought to be regulated by the preservation of the common good.  Justice refers to the common good in all matters.

Gratian shaped his first dictum that introduced the Decretum from the theological and the legal traditions.  He made a key connection between the two that has gone unnoticed.  The theological tradition had long connected the Golden Rule with natural law.  The juridical tradition did not.  The first person who connected the Golden Rule with natural law was in a letter that a disciple of Jerome wrote at his death.[20]  Prosperus of Aquitaine linked the Golden Rule to natural law in his commentary on the Psalms.[21]  Haimo of Halberstadt († 853) declared in two sermons and his biblical commentaries that natural law consisted of two principles:  “Do onto others .  .  .” and “What you do not want done to yourself, you should not do to others (cf. Tobias 4.16).  Whatever the law and the prophets will ordain can be comprehended within these two precepts.”[22]  Remigius of Auxerre († 980) rehearsed the tradition in his commentary on Genesis.[23] In the late eleventh and early twelfth century Rupert of Deutz († 1129-1130)  declared that natural law is written in the hearts of men and its expression was the Golden Rule.[24]  Hugh of St. Victor († 1141), whose work Gratian might have known, Honorius Augustodunensis († 1156) repeated the tradition.  The Golden Rule was a principle and command of natural law.[25]

            When Gratian proclaimed at the beginning of his Decretum that natural law was based on the Lex and the Gospels and that the Golden Rule was the Lex and the Prophets, he drew upon a long theological tradition.  He also incorporated the two traditional theological definitions of the Golden Rule:  “One should do to others what one would have others do to you,” and “You should not do to others what you should not want done to you.”  These two precepts, one positive and the other negative, was very similar to Ulpian’s definition of ius that I quoted earlier.[26]  Gratian, however, combined the Roman law and the theological traditions in a way that would be of fundamental importance for the future.  He combined both traditions and named them not “lex naturalis” but “ius naturale.”  His change of vocabulary enabled later jurists to incorporate the rich penumbras of meaning for ius, which as we have seen, were completely lacking in the definitions of lex.

            Gratian added his Tractatus de legibus to the second recension of his Decretum.  Recently scholars have vigorously debated the chronology of Gratian’s work.[27]  Some have placed his teaching activity in Bologna to the 1140’s.[28]  Others have argued for a much earlier date.[29]  A letter of Pope Innocent II provides evidence for Gratian’s having taught and compiled his Decretum during the 1120’s and early 1130’s.  In the arenga of a letter written in 1133, Innocent proclaimed that “Quemadmodum iuris naturalis est alterum non laedere, ita nimirum nostri officii laesum adiuvare.”^[30a]  As we have seen the two principles of natural law that the theologians embraced over the centuries were “Do onto others as you would have them do onto you” and “Do not injure others.”  We have also seen that the same two ideas can be found in Justinian’s Digest through Ulpian’s formulation: “Iuris praecepta sunt haec: honeste vivere, alterum non laedere, suum <ius> cuique tribuere.”  Consequently, whoever composed Innocent’s letter must have known Gratian’s Tractatus de legibus and the Digest, and since no one before Gratian had attributed the Golden Rule to Ius naturale, Innocent’s letter is evidence that Gratian must have finished his first draft of the Tractatus before 1133.  It is also evidence that the teaching of Roman and canon law in Bologna must have already have been in full swing by the late 1120’s and early 1130’s.

            We have seen that until the twelfth century the theologians always used the term lex naturalis.  In the thirteenth century they gradually began to incorporate the change from lex naturalis to ius naturale into their thought.  Thomas Aquinas’ works demonstrate the slow penetration of the term ius naturale into theological thought.  In his early works, especially his commentary on the Sentences of Peter Lombard (ca. 1256), Aquinas discusses natural law in depth but never uses the term ius naturale, only lex naturalis.[30]  When Thomas Aquinas discussed natural law in his Summa theologiae (ca. 1265-1272), he vacillated in his terminology between lex naturalis and ius naturale.[31]  As far as I can see he used the two terms interchangeably, and he never drew upon the rich jurisprudential discussions of the meanings of “ius.”  Other evidence points to Thomas’ having turned to and his becoming familiar with the legal tradition only in his later works.  He cited Gratian’s Decretum seven times in his Commentary on the Sentences and 81 times in his Summa theologiae.  It is not that Thomas was unaware or uninterested in law in his early writings.  He cited papal decretals 32 times in his Commentary on the Sentences.  I suspect that Thomas’ own Tractatus de legibus forced him to confront Gratian’s Tractatus as he was writing about law in his Summa theologiae.[32]

            Much of the debate about Aquinas’ thought on natural law has focused on his ideas about rights and whether his theory of natural law was compatible with the idea of subjective rights.[33]  Brian Tierney has argued that Aquinas had no theory of subjective natural rights, although Thomas did recognize that ius could mean right and that right could be a human “facultas.”[34]  Aquinas frequently used the term “facultas” to describe a person’s right and power to act.[35]  He never, as far as I can find, substituted the term ius for facultas.  This fact is, I think, some support for Tierney’s argument that Thomas did not normally think of ius as a right or power and did not have a theory of subjective rights.  As Tierney has written for Aquinas “ius was primarily a thing (rem), something existing in external nature.”[36]

            I would like, however, to make a slightly different argument from the concerns of Tierney, Finnis, and Zuckert.  As I have shown Thomas came to the concept of ius naturale late, and he never fully grappled with the full implications of how Gratian and his successors thought of natural law as a set of principles and as well as a set of rules or laws.  As far as I can tell Aquinas did not know the theological tradition that Gratian drew upon when he attributed the Golden Rule to natural law.  He only seems to have cited the Golden Rule in his later works, the Summa theologiae and  his Commentary on Matthew,  and in them Thomas never called it a principle of natural law.  Most importantly I think that Thomas’ discussion of natural law is dominated by his language.  For him natural law was lex naturalis, not ius naturale.  I believe that his language shaped his thought.

            It would go far beyond the scope of this paper to prove conclusively (or to disprove) the points that I have made in the previous paragraphs.  All of Thomas’ use of lex naturalis and ius naturale would have to be examined and compared in contextual and chronological order.  For purposes of the argument in this paper let me here just give a couple of examples of Thomas’ discussion of lex naturalis when he defined the term in question 94.

            Thomas confronted natural law and Gratian’s definition of natural law directly in his Tractatus de legibus.[37]  He began question 94 by discussing naturalis lex as a habitus.  He had already connected habitus to lex naturalis in his Commentary on the Sentences.[38]  In doing so Thomas drew upon recent theological thinking about natural law.  As we have seen, justice had been described as a habitus, since Cicero in theology and law, but natural law was never connected with habitus until the thirteenth century.  Alexander of Hales and Albertus Magnus had connected naturalis lex with habitus, and Thomas shaped his definition of naturalis lex around their opinions.[39]

            Gratian’s definition of ius naturale did not fit into Thomas’ scheme of definitions.  But it was such a well-known text by the time Thomas wrote that he had to deal with it.  He sidled up to Gratian belatedly when he asked whether the lex naturae was the same for all human beings in article 4 of question 94 and quoted Gratian’s statement that ius naturale is what is contained in the Old and New Testaments.  But since these Judeo-Christian texts are not accepted by everyone, lex naturalis is not common to all people.[40]    He put forward several counterarguments, including the text of Isidore of Seville that Gratian included at Distinction 1, canon 7.[41]   In the most important text on natural law in Gratian’s Decretum, Isidore had declared that ius naturale was common to all nations.  The canonists quickly glossed “nations” as all persons who had been born, “nascentium.”[42]  Natural law was common to all human beings.

            Thomas solved this contradiction by relying on Aristotle not the canonists.  Those principles that people are “naturally” inclined through reason pertain to natural law.[43] He was not comfortable ― or perhaps it is more accurate to say ―  or sympathetic with Gratian’s approach to natural law.  The entire text of Isidore that Gratian included in his discussion of natural law listed a series of principles to illustrate his assertion that natural law was based on the Golden Rule:[44]

Natural law is common to all nations.  It has its origins in nature not in any constitution.  Examples of natural law are the union of men and women, the procreation and raising of children, the common possessions of all persons, the equal liberty of all persons, the acquisition of things that are taken  from the heavens, earth, or sea, the return of property or money that has been deposited or entrusted.  This also includes the right to repel violence with force. These things and similar are never unjust but are natural and equitable.

Isidore/Gratian’s list of principles were not leges.   The list is a set of human relationships having their origins in nature (instinctu naturae).  All of these relationships are encompassed by rights and duties.  Men and women have the right and the duty to mate.  Men and women have the right and the duty to raise children.  Children have the right to be raised, and the duty to honor their parents.[45]  Isidore/Gratian turned to Roman law to describe other principles.  People have the right to claim ownership of “res nullius” and the right of self defense.

            Thomas, however, stumbled when he confronted “the return of property or money that has been deposited or entrusted” in Gratian/Isidore’s text.  Thomas must have asked himself, how could the Roman law contract of deposit and commodatum be a principle of natural law?  Modern readers have not always understood that Thomas was reading Isidore in Gratian and not Isidore outside of the Decretum.  Thomas did not understand that Gratian expected Isidore’s text to be interpreted through the prism of his opening statement on natural law.  Instead Thomas approached the text literally.  Is it a principle of natural law that a gratuitous contract of deposit or commodatum should always be fulfilled?[46]  The obvious answer to his literal question is no:[47]

It is right and true that all things should be done according to reason.  From this principle it follows as an almost inevitable conclusion that deposits must be returned.  And indeed this is true in many cases.  But it can happen that in a case it might be damaging and consequently would irrational if a deposit was returned.  For example if someone would use the deposit to wage war against his homeland.  <Reason> can be deficient as one descends into particular cases.  Consider if it were said that deposits must be returned with a stipulation or in another manner with particular conditions attached.  In that case the many more reasons can arise that would make it not right to either return or keep the deposit.

Thomas’ loses his grip on the legal rules governing the contract of deposit at the end.  “Cautiones” or “conditiones” could not be attached to the deposit because the contracts of deposit and commodatum would then lose their unilateral and gratuitous nature. Nonetheless, it is clear, and that is the main point, Thomas thought of this section of Gratian/Isidore’s text as a “lex” ― that is the rules of positive Roman law governing these contracts and misunderstood the rules that regulated them.  Thomas connected the obligations incurred by these contracts as founded on reason ― for him and for Gratian reason was an essential ingredient of natural law.  However, Gratian certainly and Isidore possibly were thinking of deposit and commodatum as the manifestation of the foundational principle of ius naturale in this area of law:  do unto others as other would do unto you.  The depositor or lender had to depend on the depositary’s or borrower’s honor to return the property.  No other contracts would have fallen into this category.  Consequently, the Golden Rule had great moral and ethical force in this contract and not in others that had consideration (do ut des) and conditions attached to them.  That is why Gratian and Isidore chose these contracts for their illustration of a fundamental principle of natural law.  Thomas analyzed the contract of depositum and commodatum in positivistic terms.  His first argument would have been persuasive to Gratian and the jurists:  if the return of the property resulted in damage to the common good and was unreasonable, it should not be returned.  Gratian and Isidore, however,  were propounding a much larger principle that Thomas just did not see.

            The jurists, however, understood Gratian’s point.  If Thomas had read Huguccio’s gloss on Isidore’s text he might have seen it in a different light.  Huguccio made Gratian’s point exactly in his gloss to Isidore’s text at the end of the twelfth century:[48]

“The return of property or money that has been deposited or entrusted”:  This by right (ius) or evangelical command, in which anyone is ordered to do unto others what he wishes to be done to him, and anyone is prohibited from doing unto others what she would not wish to be done to her.  Reason and the judgment of reason approves restitution that was deposited with me or was entrusted to me.

Huguccio and the canonists saw that Gratian was using Isidore to give an illustration of a principle.  He was not claiming that the Roman contracts of deposit and commodatum were in some sense a part of natural law.  They were an illustration of a principle of natural law.  Thomas did not see the connection.  It is understandable.  Thomas was not a jurist.  He did not know the intricacies of juristic thought.  As we have seen he came to Gratian’s doctrine of natural law late in his career, and there is little evidence in his work that he knew more about jurisprudence in general and natural law in particular than he found in Gratian’s Decretum.[49]

            When Thomas came back to Gratian at the end of article 4 of question 94, he returned to the question of whether all law contained in the Old and New Testament constituted natural law. The question that he posed in the beginning of the question is, to a certain extent, specious.  No jurist or theologian ever claimed that all the precepts in the Judeo-Christian texts were tenets of natural law.  Thomas conceded that he had constructed a straw man that did not reflect Gratian’s text accurately.  He concluded:[50]

It must be said to the original question that Gratian’s comment ought not be understood that almost all law contained in the Old and New Testament are laws of nature, since many things there are “above nature.”[51]  But whatever constitutes natural law is fully contained there.  Consequently Gratian said immediately, as an example and as a clarification, “The ius of nature is what is contained in the lex and the Gospel.  By it, each person is commanded to do to others what she wants done to herself.”

Thomas’ summary of Gratian’s meaning is correct.  What he did not understand is how Gratian’s conception of natural law as a principle that could be expressed by the Golden Rule of the Judeo-Christian and Roman legal traditions was linked with Isidore of Seville’s text in D.1 c.7.

            Thomas may not have understood Gratian, but his commentary on natural law in his Summa theologiae became a touchstone for all later discussions in theology and law.   In part this was because the later canonists did not write commentaries on Gratian’s Decretum and his Tractatus de legibus.  The jurists had to turn to Thomas and the theological tradition.  The only commentary on Gratian that circulated widely in the later Middle Ages was Guido de Baysio’s Rosarium that he finished ca. 1300.

            Nicholaus de Tudeschis (Panormitanus) wrote one of the only detailed commentaries on the first few chapters of Gratian’s Tractatus de legibus in the late Middle Ages.  He dealt with Thomas and Gratian in his discussion of natural law.[52]  Although his extensive commentary seems to have not circulated widely and was not generally known, it is a good example how important Thomas’ discussion of natural law had become by the middle of the fifteenth century.

            At the beginning of his commentary Panormitanus quoted Thomas’ definition of natural law that had become lapidary:  “natural law (lex naturalis) is nothing other than the impression of divine illumination on us.  Consequently, lex naturalis is every rational creature’s participation in the lex eternal.”[53]  He expanded upon Thomas’ definition using his language and terminology.  In spite of the legal tradition that eschewed the term lex naturalis, Panormitanus repeatedly adopted Thomas’ terminology.[54]  Thomas had stated that the first principle of law and therefore natural law was the necessity to do good and avoid evil.  Guido de Baysio had incorporated Thomas’ into his definition at the end of the thirteenth century but obscured Thomas’ influence by attributing the text to Laurentius Hispanus († 1248).  Panormitanus corrected him and changed Thomas’ text in a small but significant way.  It was the first principle of the law (lex) of nature to do good and avoid evil.[55]  When Panormitanus reached Gratian’s central text on natural law at D.1 c.7, his terminology began to become unstable.  As we have seen when he wrote about natural law drawing upon Thomas’ Summa theologiae, he adopted Thomas’ lex naturalis consistently.  When he began to discuss Isidore’s text, however, he began to vacillate in his terminology:[56]

Note   that these is only one lex naturalis for all people, and therefore all people have one natural instinct. .  .  . Note that lex naturalis is stamped naturally on the hearts of people  .  .  . Note in the nine examples of  ius naturale that are placed here in the text.  Do not think that <ius> naturale is restricted to these examples or that lex naturalis can be defined through them.  Many other examples might be given.

As he analyzed Isidore’s list of examples of natural law, he reverted completely to the language of the jurists:[57]

Among other examples note that the coupling of men and women is a norm of ius naturale, as the gloss notes, in so far as he says that, if this text is understood as the coupling of bodies then it ought to be understood as being a norm of ius naturale deriving from sensuality.  If however, it is understood as a coupling of souls, then the norm is just as ius naturale derived from reason. 

Panormitanus used Thomas’ terminology, mixed in with the jurists’ ius naturale, and did not seem to object to or perhaps even have noticed his unstable terminology for describing natural law.

            Panormitanus’ mixing of juristic and theological terminology was not typical of the jurists ― although theologians, as far as I can see, adopted Thomas’ lex naturalis by the early modern period.  For example Francisco Suárez († 1617) used lex naturalis almost exclusively when writing about natural law in his comprehensive treatise on law ― except when he turned to juristic thought.[58]  But Aquinas formed the bedrock of his discussion.  Yet Suárez was far from a positivist.  In the debate about who was and who was not an advocate of natural subjective rights most scholars have agreed that Suárez had a clear doctrine of rights.[59] 

            Manuel González Téllez († 1649) wrote one of the last extended canonistic discussions of natural law that was framed by the medieval jurisprudential tradition in the preface to his commentary on the Decretals of Gregory IX.[60]  Like Panormitanus Téllez used and cited Thomas Aquinas extensively.[61]  Only once, however, when discussing Thomas and natural law, did he slip into Thomas’ terminology.[62]  What is particularly striking is that Téllez wrote about natural law primarily in terms of  “praecepta (norms or maxims)” not in terms of “leges.”  The most fundamental of these norms, wrote Téllez, was that human beings should and can distinguish between good and evil.[63]  For the remainder of these norms he turned to the jurisprudential tradition.  Human beings should live honestly and should not injure their neighbors.[64]  Lastly, to give each person his ius in contracts, restitutions, and payments of debts, whose rendering may to assigned to reason and natural equity.[65]  All of these norms, Téllez concluded by turning back to Gratian’s dictum at the beginning of the Decretum, can be found in the divine wisdom of Christ’s admonition found in Matthew, chapter 7, “Do unto others as you would others do unto you.”[66] 

            When Pope Benedict XVI addressed the participants of the International Congress on Natural Moral Law in Rome on 12 February 2007 he talked about natural law:[67]

The capacity to see the laws of material being makes us incapable of seeing the ethical message contained in being, a message that tradition calls lex naturalis, natural moral law .  .  . From it flows the other more particular principles that regulate ethical justice on the rights and duties of everyone. So does the principle of respect for human life from its conception to its natural end, because this good of life is not man's property but the free gift of God. Besides this is the duty to seek the truth as the necessary presupposition of every authentic personal maturation. Another fundamental application of the subject is freedom.  Human freedom is always a freedom shared with others. It is clear that the harmony of freedom can be found only in what is common to all: the truth of the human being, the fundamental message of being itself, exactly the lex naturalis.  And how can we not mention, on one hand, the demand of justice that manifests itself in giving unicuique suum and, on the other, the expectation of solidarity that nourishes in everyone, especially if they are poor, the hope of the help of the more fortunate?

Unwittingly Benedict separated the two traditions that we have been examining.  The jurists made no distinction between ius naturale and justice, and an important aspect of justice was preserving the common good.  More significantly when Benedict thought about what constituted an example of lex naturalis, he proposed an universal lex:  the respect for human life from conception to its natural end.  Thomas Aquinas might have found fault with this lex in the same way that he objected to gratuitous contracts being called principles of natural law.  Does not human reason and human ideas of justice find ways to end lives between conception and death, he might ask.  The death penalty and the killing fields of war are two examples that he would certainly have cited.  As Thomas pointed out, how can something be called a principle of natural law if there are generally held exceptions to it?[68]

            What Benedict overlooks is his Church’s own jurisprudence.  It is what every jurist, even the pagan Roman jurists, had understood for centuries:  ius embodies justice and ius naturale in its purest form contains equity, justice, and reason in its DNA.  I would argue that the shift in terminology that we have traced has impoverished natural law thought.  Lex naturalis shifted the emphasis both yesterday and today from a set of principles, rights, and duties encapsulated in ius to positivistic sets of rules and norms, shaped and fashioned according to each person’s belief system, that are and always have been the defining feature of lex.  Human beings may never agree on universal rules of a lex naturalis, but they might agree on universal principles of a ius naturale.

            Finally, to answer the question that I posed at the beginning of this essay:  why were the bollards surrounding the Supreme Court provided with the word “Lex”?  The answer is undoubtedly “Ignorantia iuris”.