1 THE MIND OF JUPITER

On January 6, 2021, Richard Barnett, age sixty, of Gravette, Arkansas, entered the office of the Speaker of the House in the nation’s Capitol building. “I wrote her a nasty note, put my feet up on her desk,” he claimed proudly, identifying himself by name to journalists.

Of that there is no doubt. The storming of the Capitol will be remembered as a nadir of democracy, when Americans gave in to their baser selves and proved they were no more immune to the blandishments of populism than Germans, Italians, Latin Americans, or even ancient Romans had been. This lesson was not lost on the United States’ allies or her enemies.

Since Woodrow Wilson first spoke of a “moral diplomacy,” the United States held itself as an exemplar of right, justice, and good government for the world to emulate. It used its military and economic supremacy to propagate that vision, and—as with Zimbabwe—punished nations that failed to live up to it. At the definitional core of American foreign and domestic policy was a single word: freedom. Yet in the United States that most fundamental right had seemingly lost all meaning. In the aftermath of the Capitol incident a counternarrative emerged: the rioters were not an antidemocratic mob championing a would-be dictator, not at all. “These are people that understand first principles,” Fox News host Pete Hegseth maintained. “They love freedom and they love free markets and they see exactly what the anti-American left has done to democracy.”[3]

It is tempting to dismiss these words with contempt, as part of the same Orwellian gaslighting that has gone on for years among a certain segment of the American political right.

A right without definition is, by definition, no right at all. If Mr. Roy is correct, then the first and most critical task is not promulgating a new vision of human rights around the world but rediscovering for ourselves what those rights truly are. We must begin by tracing each one from its inception, considering whence it came and how it was shaped over time. Only by relearning the law can we rediscover the true definition of a natural right. Only by understanding those rights can we hope to avoid the dark vision of anarchy offered by the events of January 6.

Each natural right forms the basis of an entire discipline of legal study. But when were they first articulated, and how? Natural law skeptics like Jeremy Bentham argued that if such rights were indeed imbued in us since time immemorial, one might expect to find them equally observed in all cultures at all times. Otherwise what does “universal” denote? It may be reductive to say so, but knowledge of justice does not equate with universal pursuit. On the contrary, the earliest forms of law reflect more elemental necessities: restraining and punishing conduct harmful to the community, on the one hand; reinforcing the will of the sovereign on the other.[5] The fourth-century BCE Greek philosopher Xenophon declared that “whatsoever the ruling part of the State, after deliberating as to what ought to be done, shall enact, is Law.”[6] Law was the will of the state, neither moral nor immoral, just nor unjust.

Yet even in antiquity this was not the only view. Consider Xenophon’s contemporary, Demosthenes: “Every law is a discovery and gift of the gods, and at the same time a decision of wise men, and a righting of transgressions, both voluntary and involuntary, with the covenant of a State, in accordance with which it deems all persons in the state to live their lives.”[8] There is a great deal to unpack in this concept. The idea of law as “a discovery and gift of the gods” is the essence of natural law, yet Demosthenes is careful not to deny human agency. Wise men, having “discovered” the law, are tasked with interpreting and employing it justly. Law, far from the amoral will of the sovereign, becomes something profoundly organic—a base material discovered in nature (placed by a benevolent deity) which, if understood and utilized, produces great good. Several centuries before Cicero—and a great many more before Thomas Aquinas or William Blackstone—Demosthenes had already provided as workable a definition of natural law as any before or since.

Classical scholars grappled with another aspect of natural law: the idea that humankind is imbued with the impulse for justice. Plato introduced the idea of a perfect form of law within each person, translating into the essential goodness of humanity. Aristotle accepted the concept in part: humans were indeed imbued with knowledge of a natural law, he maintained, yet the state of placid acceptance assumed by Plato did not mesh with the realities of the world. Even if that knowledge was innate, it must be cultivated.

As for natural laws themselves, they have proved remarkably universal both in definition and application. Contrary to the relativist position that natural law is a Western construct, one finds elements of it in nearly every ancient civilization and its laws. The Chinese philosopher Mencius, living in the same era as Xenophon and Demosthenes, propounded the belief that human society is ordered by heaven according to logical principles. The purpose of sovereigns, therefore, is to uphold divine law and administer it for the benefit of their people. If they do not do so, says Mencius, the people have the right to rebel: “The people are of supreme importance, the altars to the gods of earth and grain come next; last comes the ruler. When a feudal lord endangers the altars to the gods of earth and grain he should be replaced.”[10] Thus Mencius has been described as a kind of Confucian John Locke, advancing social contract theory centuries ahead of its time. But this is only partly true. Mencius shares Locke’s views on the necessity for good (or “benevolent”) government and the conviction that rulers who deny it are violating a sacred trust. “Is there any difference between killing a man with a knife or killing him with misrule?” King Hui of Liang asks Mencius. “There is no difference,” Mencius answers.[11]

But Mencius differs from Locke in the emphasis placed on the innate character of humankind, from which springs the law itself. Divine law, or “mandate,” is instilled in every person; hence to know the law is merely to follow one’s own nature. This Platonic view contrasted sharply with the prevailing Confucian belief that society established standards of good and evil conduct and shaped each individual accordingly.

In ancient India, the Dharmashastras, or Hindu codes, laid down precise (although inconsistent) rights and duties for each person, including the rights to life, liberty, security, and property. These were so closely aligned with Western views of law that they became the basis of a standard Indian legal code drafted by British colonizers during the Raj. According to the Mahabharata, a Sanskrit epic often compared to the Christian Bible in its cultural impact, “the purpose of Law is the stability of society, the maintenance of the social order, and the general welfare of the subject.”[13] Comparisons like these cannot be taken too far. The Dharma also mandated a rigid caste system and vast inequalities between the sexes. Nevertheless, as Indian scholar Chakradhar Jha writes, “the foundation of the society of ancient India rested on enlightened states with popular sovereignty, organized administrative and judicial systems, assurance of fundamental rights and liberty of the people [and] rights in property.”[14] These early antecedents still resonate today and give the lie to claims of the “Westernization” of natural law. During the debate over the drafting of the Universal Declaration of Human Rights, political scientist S. V. Puntambekar soundly rejected the idea that natural rights were unique to Greco-Roman scholarship. “Both Manu and Buddha,” he wrote, “propounded a code as it were of ten essential human freedoms and controls or virtues of good life.” The list was strikingly familiar, not only to natural law scholars, but to those who remembered FDR’s famous speech: among them were Ahimsa (freedom from violence), Asteya (freedom from want), Aparigraha (freedom from preventable sickness), Akrodha (freedom from intolerance), Jnana (freedom of conscience), and Vidya (freedom from fear).[15]

No religion or society, however, reflects the principles and adoption of natural law more fully than Islamic civilization. The Quran states that humankind possesses fitri, an innate knowledge that Allah exists, and an impulse toward justice. This knowledge is gained through a process of deductive reasoning; the harmony between reason and divine revelation, the tawhid, is absolute. Islamicist scholar A. Ezzati writes, “While Western rationalism developed outside Christianity and mainly against Christianity, Islamic rationality grew out of Islam itself.”[16] As human nature is instilled by Allah, it must be in harmony with natural law; thus Islam recognizes both natural order, takwin, and divine law, tashri, as complementary and correlated within both the individual mind and society as a whole. Islamic scholar Muhammed al-Sharastani, writing in the twelfth century, described the relationship in almost Aristotelian terms:

The world order moves towards good, because it proceeds from the origin of good, and good is what everything desires…. When the first being knew the perfect good in potentia…it emanated from Allah, and that is the eternal providence and will. Thus good came within the divine decree essentially, while evil came accidentally…. Ultimately, evil per se is privation, the loss of a thing’s true and perfect nature.[17]

Islam recognizes four essential elements, or laws, of human nature. The first, as discussed above, is knowledge of Allah. The second is freedom, which is divinely ordained. As a creation of Allah, the individual is subservient only to Him and cannot be enslaved or pressed upon in any way without offending the deity. Thus both law and government, under Islam, follow Rousseau’s precept that each individual should enjoy as much freedom as within a state of nature, subject only to the necessity of living within a community. The third element is equality. In common with Christianity, Islam views all humans as works of divine creation and therefore fundamentally equal: “Whosoever gives life to a soul, shall be as if he had given life to mankind altogether.” Indeed, contained within the verses of the Quran is an impassioned declaration for universalism that seems tragically removed from the present state of affairs: “Oh mankind! We created you from a single pair of male and female, and made you into nations and tribes, so that you may know each other, not that you may despise and discriminate against each other.”[18]

If the third element, equality, resembles its Christian counterpart, the fourth and final is starkly different. This is humankind’s freedom from original sin. Man is a rational animal, placed on earth to perfect his existence and that of the community. He is imbued by Allah with reason, justice, and goodness. He has, in short, all the tools to fashion paradise not only on the ground before him but within his own mind. Thus Professor Ezzati concludes: “A just society is the society which is just to itself and to the entire creation at the same time. In Islam the laws governing nature are not separable from those governing man and human society. The divine order/harmony/balance is applied to man as well as to the entire creation.”[19]

Contemporaneous with the development of rationality in the Quran was a similar philosophical movement in Greece. Stoicism embraced the idea of a rational universe operating under fixed laws; as with the teachings of Islam, man’s harmony with nature depended on understanding and following these laws as closely as possible. In contrast, however, the Stoics were only superficially interested in the divine aspect of natural law; they posited that such law came from “the gods” yet this concept remained amorphous. Obeying the law honored the gods, certainly, but that was not the primary reason for so doing. Instead, aligning oneself with natural law placed the individual in harmony with nature itself. This was, ultimately, a secular philosophy delineating a certain mode of living. Stoics were known for their deference to the will of fate; “stoicism” has entered the lexicon as a synonym for resignation and endurance of great trials.

Stoicism transformed legal understandings in the West. If natural law was indeed universal, and personal harmony could be achieved only by following it, then it followed logically that all state laws must share in that universality and harmony. As Zeno of Citium described it: “A well-admired republic is founded on the principle that human beings should not be separated within cities and nations under laws particular to themselves, because all humans are compatriots…and because there is only one life and one order of things.”[20] The implications were profound. If individual harmony depended on following natural law, so too should community harmony. Therefore law could not be the will of the state or sovereign but rather adherence to a universal standard that united all humankind. From an individual philosophy, Stoicism evolved into an egalitarian foundation for law and statecraft. The causal chain was logical: “For this universe is obedient to God, and land and sea are submissive to the universe, and human life depends on the just administration of the laws of the universe, and human life depends on the just administration of the laws of order.”

These words were written by the greatest and most prolific of the Stoics, Roman statesman Marcus Tullius Cicero. “This, then, as it appears to me, has been the decision of the wisest philosophers,” Marcus tells his brother Quintus and friend Atticus in Book II of De Legibus, “that law was neither a thing to be contrived at by the genius of man, nor established by any decree of the people, but a certain universal principle which governs the entire universe, wisely commanding what is right and prohibiting what is wrong. Therefore they call that aboriginal and supreme law the Mind of Jupiter, enjoining or forbidding each thing in accordance with reason.”[21] The setting for this exchange is idyllic: Marcus, Quintus, and Atticus stroll through the gardens at Arpinum on a sunny afternoon in May. Their conversation reflects this refined atmosphere—a placid philosophical discourse in which Cicero inevitably assumes the role of sage while the others act as adoring acolytes (“With what conciseness, brother, have you brought before our eyes the duties and offices of the magistrates!”). At times Cicero seems almost like a sovereign laying down the law to his subjects. “Let the orders of the senate be free from reproach and scandal,” he pontificates, “and let them be an example of virtue to all.”[22]

But the setting is as false as the script. If Cicero enjoyed the peace of Arpinum, it was only to temporarily escape the turmoil of Rome—and perhaps preserve his own life. He wrote these words at a time when the republic was tearing itself apart. Rivalry between the two most powerful men in the Senate, Julius Caesar and Gnaeus Pompeius, or Pompey, had escalated toward civil war. The Senate split into factions: the optimates, or Old Guard, supported Pompey, while the populates, or New Men, supported Caesar. Cicero, who had served a term as consul and was widely reckoned the foremost orator of the age, found himself caught in the middle. It was a position he would retain for the remainder of his life, through Caesar’s victory over Pompey, his brief tenure as dictator, and his ultimate assassination. At each twist and turn, Cicero’s support would be sought from both sides, and with each decision he made new enemies. Having ultimately thrown his lot with the losing side twice—Pompey over Caesar and Caesars’s assassins over his avengers—Cicero’s name fell on a proscription list written by Mark Antony and Gaius Octavian. His carriage was intercepted not far from the gardens at Arpinum and he leaned his head out to the executioner, saying, “There is nothing proper in what you are doing, soldier, but do try to kill me properly.”[23]

Cicero’s personal history matters because it informs the nature of his writings. His two greatest works, De Republica and De Legibus, were both composed during times of personal crisis. In the former he was an unhappy exile in Cilicia, having fallen from power after his consulship due to the machinations of Publius Clodius. During the latter he was anxiously awaiting the outcome of a civil war he had long predicted and dreaded. The detached, almost dreamlike quality of the books deliberately distances them from the realities of Rome. Cicero is not Machiavelli, writing a practical handbook of governance. He is attempting, in the model of the Stoics, to find some rational core to the chaos around him. Thus he argues:

True law is right reason in agreement with Nature; it is of universal application, unchanging and everlasting…. We cannot be freed from its obligations by Senate or People, and we need not look outside ourselves for an expounder or interpreter of it. And there will not be different laws at Rome and at Athens, or different laws now and in the future, but one eternal and unchangeable law will be valid for all nations and for all times.[24]

This was law beyond the corruptive influence of human touch, yet as immediate and intimate as the contents of one’s own mind. It transcended not only Rome’s present troubles but Rome itself, uniting all humanity and all ages in one glorious holistic sphere. Remote it might be, but not unreachable. The gardens of Arpinum were a dream, and a very specific one—a dream of the future. Cicero knew the utopia he described was not the world in which he lived. He was, to paraphrase the Broadway musical Hamilton, planting seeds in a garden he would never see. The juxtaposition of his views on law and governance and the reality of his surroundings suggests another evolution in the understanding of natural law: that it is fundamentally progressive and aspirational. The republic might be disintegrating, yet somewhere in the ether the law remained inviolable. Too wary and shrewd to reference the present, Cicero made his case by invoking the distant past: “Again, though in the reign of Tarquin there was no written law concerning adultery, it does not follow that Sextus Tarquinus did not offend eternal law when he committed rape on Lucretia…. [The] existence of moral obligation is co-eternal with that of the divine mind.”[25] An eternal law is also an eternal promise—that in some distant time, long after the present troubles are ended, a perfect society may yet emerge. Contrasted with the senseless brutality of civil war was the perfect logic of the gods:

It is impossible that the divine mind can exist devoid of reason, and divine reason must necessarily be possessed of a power to determine what is virtuous and what is vicious…. Therefore the true and supreme law, whose commands and prohibitions are equally authoritative, is nothing other than the right reason of the Sovereign Jupiter.[26]

That was all very well, but how was mankind to access the mind of Jupiter? Through their wits, says Cicero: “For those creatures who have received the gift of reason from Nature have also received right reason, and therefore they have also received the gift of Law, which is right reason applied to command and prohibition…. As the divine mind, or reason, is the supreme law, so it exists in the mind of the sage, so far as it can be perfected in man.”[27] By this understanding, natural law is a twofold creation: the law itself and the tool—“divine reason”—needed to reach that law. The first is both eternal and immutable. The second is neither. The sage who employs reason and logic to understand divine law is nevertheless hampered by his own humanity and his times. “So far as it can be perfected in man” is a telling phrase, implying that mankind’s understanding is not perfect, may never be so, yet is perpetually evolving toward that state. This was a necessary qualifier for a man who looked with despair on the irrationality and chaos of his own era yet retained unshakeable faith in the essential rightness and orderliness of the universe. Even if the republic fell, as it ultimately would, the law fashioned by the “right reason of Jupiter” would await the next generation to rediscover it. In this belief, Cicero was a true Stoic.

The dichotomy between natural law theory and Roman reality was multilayered. If law was indeed universal, and all human beings had been given a codex within their own minds to unlock its secrets, there must be an essential equality among all persons. Zeno and Cicero both subscribed to this view. Yet neither questioned the existence of slavery in Greco-Roman society. If all humans were instilled with the divine spark, how could one enslave another? Enslavement was the antithesis of natural law: slaves had no right to property, liberty, or even their own bodies. “Nature’s laws do forbid us to increase our means, wealth and resources by despoiling others,” Cicero declared.[28] Yet Cicero owned slaves, as did practically every member of his class. Nor was the conundrum confined to slaves alone: foreigners, women, and children all had fewer “rights” under Roman law. Thus it is hard not to conclude that “right” was more akin to “privilege,” and far from establishing Stoic egalitarianism, Roman law actually reinforced caste, gender, and social distinctions.[29]

The trajectory of natural law itself is similarly murky. The idea of a transcendent law superseding even the will of the state might be considered far-fetched during the late Republic; in the Empire it was sedition. It is not surprising, therefore, to find imperial jurists backpedaling from the now-extreme views of Cicero. Gaius, writing during the placid Antonine era, nevertheless felt it prudent to declare that “what natural reason dictates to all men and is most equally observed among them is called the law of nations, as that law which is practiced by all mankind.”[30] This lowest-common-denominator approach could offend no one. A few decades later, Severan scholar Paulus rendered natural law almost meaningless, as that which “is always equitable and good.”[31] The most complete legal tract emerging from this era comes from Ulpian, head of the imperial chancellery under Septimius Severus and Caracalla, two emperors not known for their tolerance of dissent. Almost as if apologizing for Cicero’s heresy, Ulpian proffered a new definition of natural law that not only distinguished it from the law of the state but removed it from the realm of humanity altogether:

Natural law is that which nature has taught all animals; this law indeed is not particular to the human race, but belongs to all animals…. The law of nations is that law which mankind observes. It is easy to understand that this law should differ from the natural, inasmuch as the latter belongs to all animals, while the former is particular to men.[32]

Nevertheless, even if jurists in the Imperial era were reluctant to define natural law, they may have been groping toward its application. Legal historians argue that the empowerment of magistracies to protect public morals, intervene in private affairs, and maintain good order collectively represent a very modern concept: the protection of rights. The term humanum, or humanity, which Cicero used extensively in his discussion of universal law, suddenly began to appear in imperial legislation in the second century AD. “The goods these laws aim to protect are by their content similar to the rights we can read in modern human rights declarations,” scholars Jacob Giltaij and Kaius Tuori recently argued. “[I]f we proceed from a more open-ended concept of human rights…there is utility in the role and structure of those rights that can justifiably be called human rights, even when researching this concept in the ancient context.”[33]

These discrepancies and disparities are not to be wondered at. It requires vast effort to stand amidst the ruins of the Roman Forum today and reassemble them in the mind into anything coherent. A broken bit of carving or truncated column is often all we have from what was once a great temple. Reconstructing Roman law is no less daunting; of its vast catalog of jurisprudence only a tiny fraction survives. Cicero and Ulpian cite sources long since lost, and the survival of their own words owes as much to random chance as to the brilliance of their reasoning. We cannot look to Rome for a completely realized human rights law. Yet the few broken fragments that remain hint at the greater whole, and beneath the rubble of centuries it is just possible to distinguish a formidable foundation.

If Stoicism represents the first great evolutionary leap in the history of natural law, the rise of Christian scholasticism is certainly the second. It is tempting to argue that the Catholic Church did nothing more than restore the author back into the manuscript, replacing “Nature” with “God” in a manner indistinguishable from Islam. Thus “natural laws” become God’s laws, and the medium of communication is not pure reason but the revealed word of the Bible. Gratian’s Decretum, or canonical law, from the year 1140 states unequivocally: “Mankind is ruled by two laws: Natural Law and Custom. Natural Law is that which is contained in the Scriptures and the Gospel.” But in truth the relationship between natural law and Christianity was much more complex. Medieval scholastics did not abandon logic in favor of blind faith; rather, they attempted to find a middle path to reconcile reason and piety. As historian A. P. d’Entreves describes it:

An immense task lay ahead of the medieval man. The present had to be secured, the past reconquered. The lesson of Roman law was that the greatest of all legal systems had been based purely on reason and utility; the lesson of Aristotle, that the State is the highest achievement of man and the necessary instrument of human perfection. How could Roman law be accepted as the universal law of Christendom?…There must be a system of natural ethics. Its cornerstone must be natural law.[34]

That need was supplied by the thirteenth-century theologian St. Thomas Aquinas. A Sicilian nobleman who entered the Franciscan order and studied at the University of Paris under the legendary Albertus Magnus, Aquinas had greater access to written knowledge than almost any man living. This is significant, as we are speaking of an era when pre-Christian writings were regarded as heretical and access to them was strictly controlled by the Catholic Church. Just as the church appropriated the marble of the Forum to build its cathedrals and kept much of the “blasphemous” statuary in catacombs hidden from view, classical texts were stored under lock and key within private monastery collections. If not quite the daunting fortresses depicted in Umberto Eco, they were certainly a far cry from contemporary libraries. Their educational purpose was not philosophical but instructional, teaching young novitiates proper Latin and penmanship; Cicero, Aristotle, Suetonius, Livy, and Ovid were basically copybooks.

Thomas Aquinas would certainly have read these, and many more, but unlike most of his peers he actually read them. As he did, the stark outlines of a metaphysical conundrum appeared. If all “true” knowledge was contained within the Bible, what to make of the writings of a man like Cicero who had lived before Christ? Were all pre- and non-Christians damned for their ignorance, their writings contaminated as well? This did not accord with Aquinas’s view of a just God. Nor was he alone in this opinion. A quiet revolution was building within the church among scholars seeking to reconcile biblical and secular truth, which would ultimately be known as scholasticism. At the heart of this debate was natural law.[35]

Aquinas understood the debate over natural and divine law as part of an even greater question: what is humankind’s relationship with God? Echoing Muslim scholars of an earlier era, Aquinas argued it was at its core a logical one. “Supposing the world to be governed by divine Providence…it is clear that the whole community of the universe in governed by divine reason. This rational guidance of created things on the part of God…we can call the Eternal Law.”[36] Eternal law was not biblical law. It was not merely commandments but a mechanical system of infinite complexity that controlled the universe and everything within it, including humanity. But humanity was set apart from every other created thing by one distinction: its ability to understand, in some small part, the mind of God. That understanding was the basis of the unique bond between them—a bond not merely of faith but of reason. “Of all others,” Aquinas writes, “rational creatures are subject to divine Providence in a very special way; being themselves made participators in Providence itself, in that they control their own actions. So they have a certain share of divine reason itself.”[37] Thus individual will and the ability to make choices was not only a gift from God but a tiny fraction of God’s own power that set humanity apart from all creation.

Aquinas’s depiction of natural law was both a reiteration of Cicero’s and an evolution beyond it. For both, the mind of God is rational and can be accessed only by logic and reason. But Aquinas goes further: the discovery and implementation of natural law does not merely align the community with celestial harmony but is the basis of all personal morality. Each ethical choice is either an acceptance or rejection of God’s law; to deny that law is to deny reason itself. Roman gods were remote and capricious, only peripherally interested in the doings of humankind; Aquinas’s God, in contrast, has given humanity the unique ability to strive toward His own perfection (and, we may assume, remains actively interested in the process). In a neat inversion of Ulpian, Thomian natural law is not the law of animals but the law that distinguishes man from beast and places him closer to the divine.

It is not hard to see how Aquinas’s construction of natural law posed serious challenges to orthodoxy. First and foremost, it moved the locus of truth from the received word of the gospel to the individual mind; Christians were not merely to accept but to decide. Moreover, Aquinas reintroduced the Ciceronian idea of transcendent law superseding all others, even the sovereign. “Man is bound to obey secular rulers to the extent that justice requires,” he declares in his Summa Theologica. “For this reason if such rulers have no just title to power, but have usurped it, or if they command things to be done which are unjust, their subjects are not obliged to obey them.”[38] This was not merely heresy but treason. “And if human law is at variance with any particular with the Natural law,” he concludes, again echoing Cicero, “it is no longer legal but rather a corruption of law.” This statement resonates down the centuries. From this fundamental idea of justice would eventually come John Locke’s theory of the social contract. Ultimately, natural law would become the litmus test to determine the fidelity of states and justify revolution. Even as early as the end of the thirteenth century, English jurist Henry de Bracton declared the sovereign to be under the law: “Justice is the constant and unfailing will to give each his own right.”[39]

Thomas Aquinas exposed the fault lines within medieval legal, social, and spiritual philosophy. Yet ultimately the Catholic Church was grateful: by constructing a faith based on reason, he allowed the church to evolve and still retain its centrality in its parishioners’ hearts and minds. Moreover, scholastic influence revolutionized legal education. Prior to the establishment of formal schools of law, instruction on the continent centered around two principal texts: Gratian’s Decretum, discussed above, and the Decisions and Digest of the Emperor Justinian. Libra extra, papal decretals and bulls, were sometimes added to keep practitioners up to date. This sparse canon reflected the neat division in the Catholic mind between res spiritualia and res temporae, spiritual matters and secular. Any additional questions could be referred to the relevant biblical passage.

Over time, however, the list grew. Students demanded access to both local laws (understandably, as that would form the bulk of their practice) and, crucially, to classical texts that might inform their understanding of Justinian’s text. Cicero began to circulate once again. Those who studied law at university might also find themselves reading the works of Aristotle and Aquinas. Consequently, as R. H. Helmholz writes, “students thus began with texts that stated the assumption that God had implanted certain principles of conduct and justice in the hearts of men…. [They] would have heard that a fuller understanding of the law would come if they drew conclusions from morality fashioned from the law of nature…. One function of legal education was to teach students how to do this.”[40] The results were profound. Once legal training required a knowledge and understanding of natural law, the concept departed the theoretical realm and became intermeshed with statecraft. The same statesmen who fashioned their nation’s laws began their professional career with a foundation in that law’s moral, societal, and spiritual purpose.

As the law’s philosophical universe expanded, conflicts hinted at during the Roman Republic flared to life once again. If Roman jurists had been content to overlook the inconsistencies of a natural law society that possessed slaves, their medieval and Renaissance descendants could not. Indeed, Cicero’s universalism became a rallying cry for the small band of academics, jurists, philosophers, and clerics who wrote against slavery and colonization. As early as the seventh century, Saint Isidore of Seville insisted on inserting the phrase “common liberty of all” into Gratian’s Decretum, which it appears he borrowed from Cicero. The parallels were striking: if slavery was inconsistent with pagan natural law, surely it must also be with the Christian/Thomian view that saw each human being as a reflection of God.[41] Marsilius of Padua, writing in the fourteenth century, marveled at Cicero’s prescience and regarded De Officiis as “an explicit lesson about the responsibility that follows from a recognition of the common bond of humanity.”[42] The “lesson” would continue to fascinate and inspire scholars for centuries. In 1588, Jesuit theologian Luis de Molina wrote of a “concord of free will with the gifts of divine grace,” arguing controversially that God’s will works with rather than within humankind. The capacity for individual choice is thus divinely offered and therefore a basic right.[43]

Equally vexing to scholars was the problem of conquest. If all humans were fundamentally equal in the sight of God, as both Cicero and the Catholic Church declared them to be, what justification could exist for colonization? The most obvious was that the colonized—for example, the Mesoamericans under Spanish rule—were not human, in the understood meaning of the term. They had (in Spanish eyes) no civilization, no morality, and most importantly no knowledge of Christ. Nonsense, wrote jurist Francisco de Vitoria in the fifteenth century. Drawing equally from Cicero and Aquinas, Vitoria argued in De Indes that there existed a universal law of nations which “is, or is derived from, natural law.” The whole world—not just the Judeo-Christian part of it—was united in a commonwealth of morality. What of an individual raised in a “barbarian” land with no knowledge of God or Christ? Vitoria’s answer was classically Ciceronian: even that person not knowing the true God was nevertheless created by God and instilled with the same divine reason as everyone else. He or she could make rational choices that were also, by definition, moral.[44]

Vitoria’s argument is double-pronged. First, as children of God, indigenous peoples and all persons are possessed of the same capacity for morality. Second, as moral beings participating in a universal society, they cannot be dehumanized through conquest. Vitoria was not writing in a vacuum. He and other European scholars were responding to the reality of Spanish colonization in the New World and reports of horrors and atrocities committed there. Among the most outraged and influential commentators was Franciscan cleric Bartolome de las Casas, whose In Defense of the Indians was an outright indictment of Spanish rule. In contrast to paternalistic claims that the natives were incapable of governing themselves, Casas shot back:

Now if we shall have shown that among our Indians of the western and southern shores (granting that we call them barbarians and that they are barbarians) there are important kingdoms, large numbers of people with settled lives in a society, great cities, kings, contracts of the law of nations, will it not stand proved that the Reverend Doctor Sepulveda has spoken wrongly and viciously against peoples like these, either out of malice or ignorance of Aristotle’s teaching…. From the fact that the Indians are barbarians it does not necessarily follow that they are incapable of government and have to be ruled by others, except to be taught about the Catholic faith.[45]

In these words we can read the political evolution of natural law from theory to practice, and finally to legal defense. Casas’s argument shares its logical core with prosecutor Robert Jackson’s at the 1945 Nuremberg Tribunals: if there is a natural law that binds all humanity, any attempt to deny an individual’s humanity is a breach of natural law. The premise seems simple enough, but there are caveats: “Except to be taught about the Catholic faith.” Casas was writing in an era when the Catholic Church reeled under the assault of Protestantism, a challenge we will explore in the next chapter. Catholics, including Casas and his opponent Dr. Sepulveda, viewed the world as a battlefield between the forces of good and evil, perhaps even a prelude to the Last Judgment. There were no bystanders in this fight. The Mesoamericans, for all their cities and kings, could not be left “barbaric.” Like outposts of empire, they had to be converted and rallied to the cause of the True Faith. This was not only for the sake of the church but for their own salvation. Church doctrine mandated that anyone not receiving the sacraments should suffer everlasting damnation: the frescoes of Michelangelo and Hieronymus Bosch brought these horrid images vividly to life. A compassionate Catholic must save as many souls as he could before they passed into the afterlife.

Similarly, even those outraged by the practice of Spanish colonization did not necessarily discount the premise altogether. Belonging to a universal commonwealth brought privileges and obligations to both sides, Vitoria argued. Just as the Mesoamericans had the right to their freedom, so too did others have the right to pass unmolested through their territory and seize whatever might be of use to them, provided the hosts did not need or want it. Ius communicandi, the right of intercommunication, sounds innocuous enough. Yet it is not surprising that colonizers capitalized on this concept, using it to justify wholesale theft on the grounds that the native peoples did not understand the value of the precious metals beneath their soil and therefore had no right to them. Arguments like these would enjoy a long pedigree. Nineteenth-century imperialists frequently maintained that they were doing nothing more than maximizing the value of “abandoned” goods; moreover, in contrast to claims of universalism, they insisted upon a moral imperative (similar to Casas’s “except”) to bring the “barbaric” world into the light of civilization so that it might better participate in the community of nations.

By the end of the Renaissance, the interplay between statecraft and natural law had provided a foundation for the emergence of a modern conception of rights. The Magna Carta of 1215 speaks of justice, not right; the two concepts are fundamentally different. Justice is a reflection of the community, the “better ordering of our kingdom,” as the Magna Carta describes it. Right is inherently personal and individual. There were no “rights” in ancient Rome: one’s treatment in law and society was determined by their social position. Yet Cicero’s declaration of a universal brotherhood under natural law opened a path for precisely that understanding, a fact later chroniclers from Thomas Aquinas to Hugo Grotius made explicit. Domingo de Soto, writing in the sixteenth century, provides a telling example. At the basis of any just system of law, he argued, was the right to preserve one’s life from arbitrary, capricious, or cruel termination; all other rights flow from that necessity. The possession of one’s life includes all its attributes, most especially body and will. Therefore, de Soto reasoned, individuals must have rights of security and liberty as well.

This contrasted sharply with prevailing notions of justice, even in his own age. Cicero had declared that “the security of the people is the magistrate’s highest law” and for centuries all understandings of justice mirrored that communitarian perspective. “Every day,” Juan de Robles wrote, “free men lose thousands of liberties without fault, but not without cause.” Such sacrifices were necessary to the maintenance of the good of the whole. Robles compared the body politic to an actual body in which each individual is merely part of the whole. “If it is necessary for the good of the community that we lose our liberties and lives, it is just that they should be lost.”[46] Soto disagreed. In the absence of natural law, human communities might well be described as body politics, but under that law the individual remained apart and sacrosanct. “A limb does not have a being distinct from that of the whole; nor of itself can it sustain right or injury. But a man, albeit he is part of a commonwealth, is nevertheless a subject existing for the sake of himself.”[47] States could not claim that the good of the many outweighed the good of the one (although they did); proper justice, by this understanding, flowed from universal deference to individual rights, not the other way around. If sovereigns violated this trust, they offended not only the individual but, under natural law, the entire human community and God himself. It is not difficult to imagine where this argument could lead. By the eighteenth century natural law had evolved far from its original theoretical auspices into a radicalized, weaponized form.

It became the language of revolution.