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Natural Law and Natural Rights
9th Grade Social Studies · 84 lessons
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- 1What Is Natural Law?Natural law is the idea that there are moral standards built into human nature or the order of the world, which people can discover by reason and which exist whether or not any government writes them down. Its rival idea, positive law, is law that is 'posited', or laid down, by a human authority such as a king, parliament or court. The central question of this course is how the two relate: is an unjust statute still a law, and may people resist it? Defenders of natural law say it gives a yardstick for judging every legal system, which is why it has been invoked against tyranny, slavery and genocide. Critics reply that people disagree deeply about what nature or reason requires, so appeals to a higher law can become a cover for personal or religious preferences. Tracing this debate from ancient Greece to the twentieth century shows how ideas about justice shaped real revolutions, trials and declarations.
- 2Two Related IdeasAlthough the phrases sound alike, natural law and natural rights emphasize different things. Natural law traditionally speaks of duties and order: it tells people what they ought to do and what a good community looks like. Natural rights speak of entitlements that belong to each individual, such as the right to life or liberty, which others must respect. Historians debate when rights language emerged: some trace it to medieval church lawyers in the 1100s and 1200s, while others link it to seventeenth-century thinkers such as Grotius, Hobbes and Locke. The shift matters because a duty-centered theory tends to stress the common good, while a rights-centered theory tends to stress limits on what society may do to a person. Most modern declarations combine both, protecting individual rights while also speaking of duties to the community. Keeping the distinction in mind helps explain why later thinkers could agree on 'nature' yet disagree sharply on politics.
- 3Physis and Nomos: The Greek Debate over Nature and CustomIn fifth-century BCE Greece, thinkers began contrasting physis (nature) with nomos (custom or law). Travel and trade showed that peoples followed very different customs, which raised a troubling question: are moral rules simply local habits? The historian Herodotus told how the Persian king Darius asked Greeks whether they would eat their dead fathers and asked Callatian Indians whether they would burn theirs; each group was horrified by the other's practice, and Herodotus concluded that 'custom is king of all'. Some Sophists, such as Antiphon, argued that laws were artificial agreements that often clashed with nature. In Plato's dialogue Gorgias, the character Callicles went further, claiming that by nature the strong should rule the weak. Others, including Socrates and Plato, answered that reason could find standards of justice deeper than custom. This debate created the vocabulary that every later natural law theory used.
- 4Antigone and the Unwritten LawsSophocles' tragedy Antigone, first performed in Athens around 441 BCE, stages one of the oldest dramatic clashes between human decree and higher law. King Creon of Thebes forbids anyone to bury Polynices, who died attacking the city. His sister Antigone buries him anyway, telling Creon that his proclamation cannot override 'the unwritten and unfailing laws of the gods', which live 'not just today or yesterday, but always'. Creon insists that order collapses if citizens choose which laws to obey, and the play gives him real arguments, not just cruelty. Both characters are destroyed, which suggests Sophocles was exploring a genuine conflict rather than delivering a simple moral. Aristotle later quoted Antigone as an example of appealing to a universal law based on nature. Ever since, she has been a symbol for conscience against the state, cited by writers, dissidents and legal theorists.
- 5Aristotle and Natural JusticeAristotle (384–322 BCE) gave the Greek debate a more systematic form. In the Nicomachean Ethics he divided political justice into a natural part, which 'has the same force everywhere', and a legal part, which depends on what a community happens to decide, such as the size of a sacrifice. He compared natural justice to fire, which burns the same in Greece and in Persia, while admitting that even natural justice can vary at the edges. Aristotle also argued that humans are by nature political animals who flourish only within a community, so law exists not merely to prevent harm but to help citizens live well. This purpose-driven, or teleological, view of nature deeply shaped later natural law thinkers, especially Aquinas. Yet Aristotle also defended 'natural slavery', the claim that some people are fitted by nature to be ruled, an argument later used to justify the conquest of the Americas. His legacy therefore shows both the power and the danger of reasoning from 'nature'.
- 6The Stoics and the World CityThe Stoic school, founded by Zeno of Citium in Athens around 300 BCE, took natural law in a universal direction. Stoics believed the universe is ordered by logos, a divine reason running through all things, and that humans share in this reason. To live well was to 'live in agreement with nature', which meant following reason rather than passions. Because every rational being shares the same logos, the Stoics described humanity as citizens of one cosmopolis, a world city, regardless of their local state. This was a striking idea in a world of city loyalties and slavery: the Stoic Epictetus had himself been enslaved, and the emperor Marcus Aurelius followed the same philosophy. Critics note that Stoics often stressed inner freedom and acceptance rather than reforming unjust institutions. Still, the ideas of a single law for all rational beings and a shared human citizenship passed through Cicero and Roman law into Christian and modern thought.
- 7Cicero: True Law Is Right ReasonThe Roman statesman Marcus Tullius Cicero (106–43 BCE) wrote the most quoted ancient definition of natural law. In his dialogue On the Republic, written around 54–51 BCE, he declared that 'true law is right reason in agreement with nature', universal, unchanging and eternal. Such a law, he said, cannot be repealed by the Senate or the people, and 'there will not be one law at Rome and another at Athens'. In On the Laws he argued that a decree contrary to justice no more deserves the name of law than a harmful prescription deserves to be called medicine. Cicero was translating Stoic ideas into Roman political language, and he wrote during the crisis that destroyed the Republic, which gives his appeal to unchangeable law an urgent tone. He was killed in 43 BCE on the orders of Mark Antony. Through Christian writers who preserved his words, Cicero carried natural law into the Middle Ages and the Renaissance.
- 8Roman Law: Civil Law, the Law of Nations and Natural LawRoman jurists did not just philosophize; they built natural law into a working legal vocabulary. They distinguished ius civile, the law of a particular state such as Rome, from ius gentium, the 'law of nations' observed among all peoples, such as rules on contracts and trade. The jurist Gaius, writing around 161 CE, said the law of nations is what 'natural reason establishes among all men'. A later jurist, Ulpian (died in the 220s CE), defined ius naturale more broadly as what nature has taught all animals, such as the bond between parents and offspring. These categories were practical: Roman courts needed rules for dealing with foreigners who were not Roman citizens. Emperor Justinian's lawyers gathered these opinions into the Digest and the Institutes in 533 CE. When the Digest was rediscovered in Italy in the late eleventh century, it gave medieval lawyers a ready-made framework for thinking about law beyond any one kingdom.
- 9Born Free: Roman Jurists on Slavery and NatureRoman law contained a revealing tension about slavery. Ulpian wrote that 'by natural law all people are born free', and Justinian's Institutes described slavery as an institution of the law of nations 'by which a person is, contrary to nature, subjected to the ownership of another'. Yet Roman society depended heavily on slave labor, and the same law books contain detailed rules about buying, selling and freeing enslaved people. Jurists resolved the tension by saying that the law of nations, created by human practices such as war, could override natural freedom. This shows how a natural law ideal could be acknowledged in theory while an injustice continued in practice. Centuries later, opponents of slavery would seize on such admissions: if slavery was contrary to nature, why should any legal system tolerate it? The Roman texts thus reveal both the limits of ancient natural law and the seeds of later arguments for abolition.
- 10Paul, Augustine and the Law Written on the HeartEarly Christian writers absorbed Greek and Roman ideas of natural law and connected them to their own beliefs. In his letter to the Romans, written around 57 CE, the apostle Paul spoke of non-Jews who 'do by nature what the law requires', showing that its work is 'written on their hearts'. Christian thinkers read this as evidence that all people, not just believers, could know basic moral truths through conscience. Augustine of Hippo (354–430) added an influential claim in On Free Choice of the Will: 'a law that is not just seems to be no law at all'. Augustine also held that human government exists partly because of human wrongdoing, so earthly law is limited and imperfect compared with eternal law. These ideas did not form a full theory, but they gave medieval Christian thinkers a framework linking conscience, reason and divine law. Teaching them descriptively helps explain why natural law became central to medieval European thought.
- 11Gratian, the Canonists and the Birth of Rights TalkAround 1140 a teacher at Bologna known as Gratian compiled thousands of church texts into a single textbook, the Concordance of Discordant Canons, usually called the Decretum. It opened by stating that humankind is ruled by two things, natural law and custom, and borrowed Isidore of Seville's definition of natural law as 'common to all nations'. Commentators on Gratian, called canonists or decretists, debated what natural law meant and began using the word ius to describe a power or faculty belonging to a person. Some argued that a poor person in extreme need had a right to take what was necessary to survive, because property arrangements could not override the basic needs of life. Historian Brian Tierney argued in 1997 that this was the true beginning of natural rights language, centuries before Locke. Others think the medieval usage was narrower. Either way, the canonists show that rights thinking grew from careful legal scholarship, not only from revolutionary pamphlets.
- 12Is Natural Law Only Western? Comparative PerspectivesNatural law as a named theory grew mainly in Greek, Roman and Christian Europe, but similar questions appear in other traditions. The Chinese philosopher Mencius (c. 372–289 BCE) argued that human nature contains 'sprouts' of compassion, shame, respect and moral judgment, which good government should cultivate. In Islamic theology, the Mu'tazili school held that human reason can recognize some acts as good or bad, while the Ash'ari school held that moral value is known through divine command; both sides were debating questions close to natural law. Many African and Indigenous traditions describe moral order as part of a wider balance between people, ancestors and the natural world. Scholars disagree about how far these should be called 'natural law', since each has its own concepts and purposes. Comparing them helps avoid two errors: assuming only Europe asked these questions, and assuming every tradition gave the same answers.
- 13Aquinas's Four Kinds of LawThomas Aquinas (c. 1225–1274), an Italian Dominican friar who taught at Paris, built the most complete medieval theory of natural law in his Summa Theologiae. He defined law as 'an ordinance of reason for the common good, made by whoever has care of the community, and promulgated'. He then described four kinds of law. Eternal law is God's rational plan for the whole universe. Natural law is the share of eternal law that humans grasp through reason. Human law is the specific rules communities make to apply natural law to local conditions. Divine law, revealed in scripture, guides people toward goals beyond this life. The scheme was powerful because it gave reason, not just authority, a central role: a human law gains its force from being reasonable and aimed at the common good. Aquinas drew heavily on Aristotle, whose works had recently been translated into Latin, and on Roman and church law, weaving them into one system.
- 14Do Good, Avoid Evil: Aquinas's First PreceptHow do people actually know natural law? Aquinas argued that, just as the mind grasps first principles of logic without proof, practical reason grasps a first principle of action: 'good is to be done and pursued, and evil avoided'. Everything else follows from what humans are naturally inclined toward. Like all living things, people seek to preserve their lives; like other animals, they are inclined to have and raise children; and as rational beings, they seek to know the truth about God and to live in society. From these inclinations come more specific precepts, such as avoiding ignorance and not harming those we live among. Aquinas held that the most general principles are the same for everyone, but the more detailed the conclusion, the more often it can fail or be unknown. Critics later objected that moving from what we are inclined to do to what we ought to do is a logical leap, a challenge David Hume would sharpen in the 1700s.
- 15From Principles to Statutes: Conclusion and DeterminationIf natural law is general, how do communities get specific laws such as speed limits or tax rates? Aquinas answered that human law derives from natural law in two ways. Some laws follow as conclusions: from 'do no harm' comes 'do not kill', which is binding partly because it expresses natural law itself. Other laws are determinations, like an architect choosing the exact shape of a house within the general idea of a house. Natural law requires that wrongdoers be punished, but it does not say whether the penalty should be a fine or prison; human lawmakers must decide. This distinction explains why many laws can differ across countries without either being unjust, and why some laws, such as bans on murder, appear almost everywhere. It also limits natural law's ambitions: it does not dictate every rule, leaving wide room for political choice, custom and democratic debate.
- 16Aquinas on Unjust Laws and the Duty to ObeyAquinas asked whether people are bound in conscience to obey every human law. He answered that a law is just when it serves the common good, stays within the lawmaker's authority and distributes burdens fairly. A law that fails these tests, he wrote, is 'more an act of violence than a law', and does not bind conscience. Yet he added an important qualification: a person may still have reason to obey an unjust law to avoid scandal or public disorder, since resisting can sometimes cause greater harm. Only laws commanding something against divine law, such as idolatry, must never be obeyed. This careful position avoided two extremes: blind obedience on one side, and a license to break any law one dislikes on the other. Later thinkers, from sixteenth-century resistance theorists to Martin Luther King Jr., drew on this reasoning when debating when disobedience is justified.
- 17Just War Theory in the Natural Law TraditionNatural law thinkers did not only ask how to govern in peace; they asked whether war could ever be just. Augustine argued that war might be justified to restore peace and punish wrongdoing, though always as a tragic necessity. Aquinas set out three conditions: war must be declared by a legitimate authority, not a private person; it must have a just cause, such as righting a wrong; and it must be fought with right intention, aiming at peace rather than cruelty or revenge. Later thinkers added further tests, including last resort, proportionality and protection of non-combatants. Aquinas also developed reasoning later called the 'principle of double effect', which considers when an action with a foreseen harmful side effect may be permitted. Supporters see just war theory as a realistic way to restrain violence; pacifist critics argue it too easily justifies war. Its categories still shape the modern laws of armed conflict.
- 18Reason or Will? Scotus, Ockham and VoluntarismAfter Aquinas, philosophers argued about a deep question: is something good because God commands it, or does God command it because it is good? Aquinas leaned toward reason: God's law reflects a rational order, so it is in principle intelligible. The Franciscan thinkers John Duns Scotus (c. 1266–1308) and William of Ockham (c. 1287–1347) gave more weight to God's will and freedom. Scotus held that some commandments, especially those about our duties to other people, depend more directly on God's free choice than the core duties toward God. Ockham went further, suggesting that moral obligation rests ultimately on divine command. This position, called voluntarism, matters for natural law because it raises doubts about whether reason alone can discover moral truths. The debate echoes an old question posed in Plato's Euthyphro, and it would resurface in the 1600s when Grotius suggested natural law would hold even if, hypothetically, God did not exist.
- 19Can Anyone Own Nothing? The Franciscan Poverty DisputeIn the 1320s a dispute about friars' poverty became a turning point in the history of rights. The Franciscan order held that Christ and the apostles owned nothing, and that friars merely used goods without holding any right to them. Pope John XXII rejected this, arguing that using up food without owning it was impossible and, in 1323, declaring it heretical to say Christ and the apostles owned nothing. To answer him, William of Ockham and others sharpened definitions of ius, distinguishing a legal right enforceable in court from a natural power to use things needed for life, which no one could give up. Ockham, who had fled to the protection of Emperor Louis IV in Munich, also argued that rulers, including popes, could not override certain natural liberties. The quarrel looked technical, but it forced thinkers to define what a right is, and historians see it as an important step toward later natural rights theories.
- 20Francisco de Vitoria and the Rights of Indigenous PeoplesThe Spanish conquest of the Americas forced natural law thinkers to ask whether non-Christian peoples had rights. Francisco de Vitoria (c. 1483–1546), a Dominican professor at the University of Salamanca, gave a famous lecture, On the Indians, in 1539. He argued that the Indigenous peoples of the Americas possessed true dominion, meaning legitimate ownership and government, before the Spaniards arrived, and that being non-Christian did not cancel it. He rejected claims that the pope or emperor were lords of the whole world, and denied that discovery gave Spain title to lands already owned. Yet Vitoria also listed possible 'just titles', such as a natural right to travel, trade and preach, which could justify Spanish intervention if resisted. Scholars therefore debate his legacy: some see him as a founder of international law and human rights, while others see his arguments as a more sophisticated justification of empire.
- 21The Valladolid Debate: Las Casas and SepúlvedaIn 1550 and 1551, Emperor Charles V paused new conquests and convened a council of jurists and theologians at Valladolid to hear a debate on how Spain should treat the peoples of the Americas. Juan Ginés de Sepúlveda, a scholar of Aristotle, argued that some Indigenous peoples were 'natural slaves' who could be justly conquered for their own benefit and to end practices such as human sacrifice. Bartolomé de las Casas, a Dominican friar who had once held an encomienda himself, answered that Indigenous Americans were fully rational, had legitimate societies and could only be converted peacefully. Both men appealed to natural law, showing that the same tradition could support opposite conclusions. The council never issued a clear verdict, and abuses continued. Even so, the debate is remarkable as an empire publicly questioning the morality of its own conquests, and Las Casas's writings became influential in later human rights thinking.
- 22Francisco Suárez: Law, Consent and the CommunityThe Jesuit theologian Francisco Suárez (1548–1617) brought the School of Salamanca's thinking to a peak in his treatise On Laws and God the Lawgiver, published in 1612. Suárez blended Aquinas's emphasis on reason with the voluntarist insistence on will: natural law shows what is good, but it binds as law because God commands it. He also argued that political power comes from God not directly to kings but to the community as a whole, which then transfers it to a ruler. This meant the people were the original holders of political authority, an idea with radical potential. Suárez used this view to reject the theory of the divine right of kings defended by James I of England. He also distinguished natural law from the law of nations, which he saw as customs common to almost all peoples. His work was widely studied in Catholic and Protestant universities, linking medieval scholasticism to early modern political theory.
- 23Richard Hooker and English Natural LawIn Protestant England, Richard Hooker (1554–1600) defended the Church of England with a natural law argument in Of the Laws of Ecclesiastical Polity, whose first books appeared in 1593. Puritan critics claimed that scripture alone should govern church and state. Hooker replied that God also speaks through reason, and that much of law, including how a church is organized, is left to human judgment guided by natural law. He followed Aquinas in describing a hierarchy of laws, but he wrote in elegant English for a wider audience. Hooker also argued that the lawful power to make laws for a whole society belongs to that society, so laws imposed without public approval are 'no better than mere tyranny'. Nearly a century later, John Locke quoted 'the judicious Hooker' repeatedly in his Second Treatise. Hooker thus served as a bridge between medieval natural law and English political thought about consent.
- 24Jean Bodin: Sovereignty Bound by Natural LawIn 1576, after years of religious civil war in France, Jean Bodin published Six Books of the Commonwealth, which defined sovereignty as 'the absolute and perpetual power of a commonwealth'. Bodin believed France needed a single supreme authority that no faction could override, and he argued that a true sovereign cannot be bound by its own laws or need anyone's consent to legislate. Yet even Bodin insisted that the sovereign remains subject to the laws of God and of nature. A ruler, he said, should keep promises, respect subjects' property and not seize goods without just cause. This combination is important: the founding theorist of sovereignty still thought a higher law limited power, even if no court could enforce it. Later thinkers debated whether such limits mean anything without enforcement, a question that leads directly to Hobbes and to the modern debate between natural law and legal positivism.
- 25Hugo Grotius and the Law of War and PeaceHugo Grotius (1583–1645) is often called a founder of modern natural law and of international law. A Dutch prodigy who entered Leiden University at eleven, he was imprisoned for life in 1619 after a religious and political conflict in the Dutch Republic, escaped two years later and lived in exile in Paris. There, horrified by the brutality of the Thirty Years' War, he published On the Law of War and Peace in 1625. He wrote that he saw 'a lack of restraint in relation to war such as even barbarous races should be ashamed of', with men rushing to arms for trivial reasons. Grotius argued that natural law, together with the agreed law of nations, binds states in war as well as in peace, setting limits on why wars may be fought and how. By grounding these rules in human nature rather than in any single church, he offered a framework that Catholic and Protestant states alike could accept.
- 26Even If God Did Not Exist: Grotius's Famous HypothesisIn the prologue to On the Law of War and Peace, Grotius made a bold claim: what he had said about natural law 'would have a degree of validity even if we should concede that which cannot be conceded without the utmost wickedness, that there is no God'. Grotius himself was a sincere Christian who wrote works of theology, so he was not denying God. His point was that natural law rests on human nature and reason, and would therefore be valid on its own terms. He also wrote that just as even God cannot make two times two not equal four, God cannot make what is intrinsically evil be good. Some historians see this as a decisive step toward a secular natural law that people of any faith, or none, could share. Others note that medieval scholastics such as Gregory of Rimini had made similar points, so Grotius was developing an existing idea rather than inventing one.
- 27Mare Liberum: Natural Law and the Freedom of the SeasGrotius's first major work on the law of nations grew out of a commercial quarrel. In 1603 the Dutch East India Company seized the Portuguese ship Santa Catarina in the Singapore Strait, and its rich cargo raised questions about whether the capture was lawful. Grotius was asked to defend the Company, and part of his argument was published in 1609 as Mare Liberum, The Free Sea. He argued that the ocean, like air, cannot be occupied or enclosed, so by natural law it is open to all nations for navigation and trade. Portugal's claim to control routes to the East Indies, he said, violated this natural freedom. Critics noted that the argument served Dutch commercial interests, and England's John Selden replied in 1635 with Mare Clausum, The Closed Sea, defending national control of waters. The episode shows natural law reasoning applied to practical disputes, and how principle and interest can be intertwined.
- 28Sociability and Rights as Moral QualitiesGrotius built his theory on a claim about human nature. Against skeptics who said people act only for their own advantage, he argued that humans have an 'appetite for society', a desire for peaceful and orderly life with others of their kind. Natural law, in his view, consists of the rules needed to maintain such a society: abstaining from what belongs to others, returning what we hold of theirs, keeping promises, repairing damage we cause, and accepting punishment when deserved. Grotius also defined a right as 'a moral quality of a person, enabling him to have or to do something justly'. This made rights something individuals possess, which they can exercise, transfer or defend. Because rights could be transferred, Grotius thought people might even give up liberty to a ruler, so his theory could support absolute government. His rights-based framework was nonetheless a major step toward the individual natural rights later used against rulers.
- 29Hobbes's State of NatureThomas Hobbes (1588–1679) wrote Leviathan, published in 1651, after living through the English Civil War. He asked readers to imagine a 'state of nature' with no government. Because people are roughly equal in ability, compete for scarce resources, fear one another and seek glory, he argued, they would fall into 'a war of every man against every man'. In such a condition there would be no industry, no arts, no society, and the life of man would be 'solitary, poor, nasty, brutish, and short'. Hobbes did not claim that all humanity once lived like this; he pointed to civil war and to relations between sovereigns as examples of what happens when no common power keeps order. His thought experiment broke with Aristotle's view that humans are naturally political animals. Critics have objected that it underestimates human cooperation, but supporters argue it captures how insecurity can drive even decent people to violence.
- 30Hobbes's Laws of NatureHobbes kept the vocabulary of natural law but transformed its meaning. He distinguished the right of nature, the liberty each person has to use their own power to preserve their life, from a law of nature, a rule found by reason forbidding a person to do what destroys their life. The first law of nature is to seek peace and follow it, while defending oneself by any means if peace cannot be had. The second is to be willing to lay down one's right to all things when others are willing too. The third is to keep the agreements one makes, which Hobbes called the source of justice. He listed nineteen laws in all, including gratitude, equity and the safe conduct of mediators. Unlike Aquinas, Hobbes presented these laws as rules of prudence for survival rather than as a moral order reflecting divine reason. They bind in conscience always, he said, but bind in action only when others can be trusted to obey them too.
- 31Hobbes's Sovereign and the Limits of ObedienceTo escape the war of all against all, Hobbes argued, people covenant with one another to transfer their right of governing themselves to a sovereign, a person or assembly whose power is undivided and very nearly absolute. Subjects cannot rightfully overthrow the sovereign, and the sovereign's commands define justice and property within the state. Yet Hobbes built one crucial exception into his system. Since people make the covenant to preserve their lives, they cannot give up the right to resist those who come to kill, wound or imprison them. A condemned prisoner, he wrote, may lawfully try to escape, and a person may refuse a command to kill himself. Obedience lasts only as long as the sovereign can protect. This small space for self-preservation has led some scholars to see Hobbes, surprisingly, as a forerunner of individual rights, while others emphasize how much power he gave the state. His blend of absolutism and individualism makes him hard to classify.
- 32Spinoza: Right as Power and Freedom of ThoughtThe Dutch philosopher Baruch Spinoza (1632–1677) offered one of the most radical reinterpretations of natural right. In his Theological-Political Treatise, published anonymously in 1670, he argued that every natural thing has as much right as it has power: big fish, by natural right, eat small fish. Natural right, in this sense, is not a moral permission but simply the extent of what something can do. Yet Spinoza drew surprising conclusions. Because no ruler can truly control people's thoughts, he argued, a government that tries to do so is acting against its own power and will provoke resistance. The real purpose of the state, he wrote, is freedom, and a wise state allows people to think what they like and say what they think. Spinoza had been expelled from Amsterdam's Portuguese Jewish community in 1656, and his treatise was widely condemned. He shows that a power-based view of right could still support toleration and free expression.
- 33Samuel Pufendorf and the Duties of SocialitySamuel Pufendorf (1632–1694), a German jurist, turned natural law into a university subject across Protestant Europe. In 1661 he became one of the first professors of natural law, at Heidelberg, and in 1672 he published On the Law of Nature and of Nations, followed by a shorter textbook, On the Duty of Man and Citizen, in 1673. Pufendorf combined Grotius's emphasis on sociability with Hobbes's realism about human weakness: because people are vulnerable and need one another, the fundamental natural law is to cultivate and maintain sociality. He organized natural law into duties toward God, oneself and others, and stressed natural equality, arguing that every person must treat others as equally human. Pufendorf's textbooks were translated into many languages and taught for over a century, including in colonial American colleges. He made natural law a structured, teachable system, which helped carry its ideas to the generation that drafted revolutionary declarations.
- 34Emer de Vattel and the Equality of NationsThe Swiss jurist Emer de Vattel (1714–1767) applied natural law to the relations between states in The Law of Nations, published in 1758. Writing in clear French for diplomats and statesmen rather than professors, he argued that nations, like individuals in the state of nature, are free, independent and equal. He famously compared them to people: 'a dwarf is as much a man as a giant', and a small republic is no less sovereign than the most powerful kingdom. Vattel distinguished the 'necessary' law of nations, derived from natural law and binding on conscience, from the 'voluntary' law that states must accept in practice because no one can judge between them. Critics argue that this practical concession weakened the moral force of natural law in international affairs. His book became a standard reference for diplomats, courts and revolutionaries, and leaders of the new American republic consulted it as they asserted their independence.
- 35Natural Law and Slavery: Justifications and ChallengesEarly modern natural lawyers did not oppose slavery as a group, and their writings show how a theory of rights could coexist with grave injustice. Grotius and Pufendorf accepted that people might become enslaved through captivity in a just war or by agreement. Locke wrote that slavery was legitimate only as the continuation of a state of war between a lawful conqueror and a captive, yet he was involved in English colonial administration and invested in the Royal African Company, which traded enslaved Africans. Historians debate how to interpret this gap between principle and practice. At the same time, natural law gave critics powerful tools. In the mid-1700s, the Scottish philosopher Francis Hutcheson argued that no one could be justly owned, and abolitionists later insisted that if all people were born free, no law could make them property. The same tradition was used on both sides, which shows the importance of examining how ideas were applied, not just stated.
- 36Mary Astell and the Question of Women's Natural FreedomIf natural law teaches that people are born free and equal, what about women? Most early modern natural lawyers placed husbands above wives, often claiming this reflected nature or consent. A few writers challenged this. The French philosopher François Poulain de la Barre argued in 1673, using Descartes's method, that 'the mind has no sex', so women's apparent inferiority came from custom and lack of education. In England, Mary Astell (1666–1731) proposed academies for women in A Serious Proposal to the Ladies (1694) and examined marriage in Some Reflections upon Marriage (1700). In a preface to a 1706 edition she asked pointedly: 'If all Men are born free, how is it that all Women are born Slaves?' Astell was a political conservative who supported the monarchy, so she used the logic of natural freedom to expose the inconsistency of its champions rather than to endorse their politics. Her question anticipated arguments later made by women's rights advocates.
- 37Locke's Two Treatises: Purpose and ArgumentJohn Locke (1632–1704) published Two Treatises of Government anonymously in late 1689, though much of it was probably written around 1679–1681 during England's Exclusion Crisis, when opponents of the future James II feared Catholic absolutism. The First Treatise attacked Sir Robert Filmer's Patriarcha, which claimed that kings inherited absolute authority from Adam, the first father. The Second Treatise set out Locke's own theory: people are naturally free and equal, they have rights to life, liberty and property, and they form governments by consent to protect those rights. A government that betrays this trust may be resisted and replaced. Locke presented these ideas as conclusions of reason drawn from the law of nature, which he also connected to God as creator. Because it appeared just after the Revolution of 1688–89, readers long treated it as a justification of that revolution, but its philosophical claims reach far beyond one English crisis.
- 38Locke's State of Nature: Liberty, Not LicenseLocke's state of nature looks very different from Hobbes's. He described it as a state of perfect freedom and equality, but 'though this be a state of liberty, yet it is not a state of licence'. It has a law of nature to govern it, and reason, which is that law, teaches that no one ought to harm another in life, health, liberty or possessions. Locke argued that in this state everyone holds the 'executive power of the law of nature', the right to punish those who break it. The trouble is not constant war, but inconvenience: people are biased judges in their own cases, there is no settled law everyone knows, and victims may lack the power to enforce their rights. Government is created to supply impartial judges, known laws and reliable enforcement. Because people already have rights before government exists, Locke's government is limited: it holds power only in trust to protect what people already possess.
- 39Life, Liberty and Estate: Locke's Theory of PropertyLocke's most original argument concerned property. God gave the earth to humankind in common, he said, so how can anyone rightfully own a particular piece of it? His answer was labor. Every person has 'a property in his own person', and by mixing their labor with something from nature, such as picking acorns or cultivating land, they make it their own. Locke also argued that labor creates most of the value in things, so cultivated land is far more valuable than wild land. He used 'property' in a broad sense, saying people unite in society to preserve their 'lives, liberties and estates', which he called by the general name property. This theory gave individuals a strong claim against rulers who taxed or seized goods without consent. Later thinkers drew very different conclusions from it: some used it to defend private enterprise, while early socialists argued that if labor creates value, workers deserve its fruits.
- 40Enough and As Good: Locke's Limits and Their CriticsLocke placed two limits on acquiring property through labor. First, a person may take only as much as leaves 'enough, and as good' for others. Second, no one may take more than they can use before it spoils. However, Locke argued that the invention of money, which does not spoil, allowed people to accumulate large possessions by tacit agreement, which seemed to loosen these limits. Critics have found further problems. Locke wrote that 'in the beginning all the world was America' and suggested that land not enclosed and farmed in the European manner was largely 'waste'. Political theorist James Tully and others have argued that this reasoning helped justify taking land from Indigenous peoples of the Americas, whose own forms of land use Locke did not recognize as creating property. Defenders reply that Locke's provisos can be read as demanding fairness to others. The debate shows how a philosophical argument can carry assumptions shaped by its historical setting.
- 41Consent: Express and TacitFor Locke, legitimate government rests on consent: since all people are naturally free, no one can be put under another's political power without agreeing to it. But very few people ever sign a contract with their government. Locke answered with a distinction. Express consent is an explicit promise, such as an oath, which makes a person a full member of the society. Tacit consent is implied by enjoying the benefits of a government's protection, for example by owning land or even 'travelling freely on the highway'. Critics found this troubling: if merely walking on a road counts as consent, almost anyone could be said to have agreed to almost anything. Locke also said the majority's decision binds the whole community, since a body must move one way. Modern democratic theory continues to wrestle with his problem of explaining why people born into a state are obliged to obey it.
- 42The Appeal to Heaven: Locke's Right of ResistanceLocke's most radical conclusion concerned resistance. Government is a trust, he argued, created to protect life, liberty and property. When rulers act against that trust, for example by seizing property, altering the legislature or trying to make themselves absolute, they put themselves in a state of war with the people. In such cases the people may resist and establish a new government. Who decides when this has happened? Locke answered that 'the people shall be judge', and when no earthly judge exists, the only remedy is an 'appeal to heaven', meaning a resort to force with the outcome left to God's judgment. He insisted that people would not rebel over minor mistakes, only after 'a long train of abuses'. Critics feared this invited constant rebellion; Locke replied that tyranny, not resistance, was the real cause of disorder. These ideas later echoed loudly in the American Declaration of Independence.
- 43Hobbes and Locke ComparedHobbes and Locke both started from a state of nature and a social contract, yet they reached sharply different conclusions. Hobbes saw natural life as war, so almost any government was better than none, and the sovereign's power had to be nearly absolute. Locke saw the state of nature as governed by moral law, so government was a limited trust that could be resisted if it abused its power. Their views of human nature differ: Hobbes stressed fear and competition, Locke stressed reason and the capacity to respect others' rights. Their views of rights differ too: Hobbes's subjects keep little beyond self-preservation, while Locke's citizens keep life, liberty and property. Historical context helps explain the contrast, since Hobbes wrote amid civil war and Locke amid fear of royal absolutism. Comparing them shows how assumptions about human nature shape conclusions about government, a lesson useful for analyzing any political theory.
- 44Rousseau's State of Nature and the Origin of InequalityJean-Jacques Rousseau (1712–1778), born in Geneva, challenged both Hobbes and Locke in his Discourse on the Origin of Inequality, published in 1755. He argued that earlier theorists had projected the vices of civilized people back onto 'natural' humans. In Rousseau's imagined state of nature, people were solitary, simple and largely peaceful, guided by self-preservation (amour de soi) and natural pity for others' suffering. Inequality and conflict arose later, with settled society, comparison and the desire for esteem, which he called amour-propre. Above all, he blamed private property: 'The first man who, having enclosed a piece of ground, thought of saying This is mine, and found people simple enough to believe him, was the real founder of civil society.' Rousseau claimed the first social contract was a trick by the rich to protect their gains. Critics called his picture of natural humanity unrealistic, but his argument made inequality itself a central philosophical problem.
- 45Rousseau's Social Contract and the General WillRousseau's Of the Social Contract (1762) opens with a famous line: 'Man is born free, and everywhere he is in chains.' His goal was not to return to nature but to find a form of association in which each person, while uniting with all, 'obeys only himself and remains as free as before'. His answer was that each citizen gives themselves wholly to the community, which then acts through the general will, the will directed toward the common good of all. Rousseau distinguished the general will from the 'will of all', which is merely the sum of private interests. Sovereignty, he held, belongs to the people as a whole and cannot be transferred or represented, so laws are legitimate only when citizens make them together. This was a powerful theory of popular sovereignty, influential in the French Revolution. Unlike Locke, Rousseau gave less weight to rights held against the community, which became a central point of later criticism.
- 46Forced to Be Free? Critics of the General WillOne sentence in the Social Contract has provoked controversy for centuries: whoever refuses to obey the general will 'shall be compelled to do so by the whole body', which means nothing else than that 'he will be forced to be free'. Rousseau meant that true freedom is obeying a law one has prescribed for oneself as a citizen, so compelling someone to follow the general will restores their real freedom against their private impulses. Critics see danger here. The philosopher Isaiah Berlin argued that this 'positive' idea of liberty can let rulers claim to know people's true will better than they do, justifying coercion in freedom's name. Historian J. L. Talmon linked Rousseau to what he called 'totalitarian democracy'. Defenders reply that Rousseau insisted on equal laws made by all citizens, strongly opposed tyranny, and should not be blamed for later misuses. The debate turns on whether freedom means being left alone or governing oneself together.
- 47Three Social Contracts Side by SidePlacing Hobbes, Locke and Rousseau side by side reveals the flexibility of social contract thinking. All three imagined people moving from a state of nature to political society by agreement, and all three used this story to explain what makes authority legitimate. Hobbes's contract creates a powerful sovereign to end fear; Locke's creates a limited government to protect rights; Rousseau's creates a self-governing people whose general will is sovereign. Their contracts differ in who the parties are, what is surrendered and what remedy exists if government fails. None of them claimed that most states were actually founded by such agreements; the contract was a way of testing whether authority could be justified to free and equal people. In 1971 the American philosopher John Rawls revived this method in A Theory of Justice, asking what principles people would choose behind a 'veil of ignorance' about their own position. The contract idea thus remains a living tool of political reasoning.
- 48Challenging the Contract: Hume, Pateman and MillsSocial contract theory has faced powerful criticism. In 'Of the Original Contract' (1748), David Hume argued that almost all governments were founded on conquest or usurpation, not consent, and that tacit consent is a fiction. A poor peasant who knows no foreign language, he said, has no more real choice to leave his country than a man carried aboard a ship while asleep has to leap into the ocean. Hume thought people obey government mainly from habit and because it is useful. In the twentieth century, other critics asked who was left out of the contract. Carole Pateman's The Sexual Contract (1988) argued that classic contract theories assumed a prior subordination of women in marriage. Charles W. Mills's The Racial Contract (1997) argued that in practice the contract often included only white Europeans and excluded colonized and enslaved peoples. Defenders reply that the contract ideal itself demands universal inclusion, so these critiques show how to apply it more consistently.
- 49Self-Evident Truths: The Declaration's PhilosophyThe Declaration of Independence, approved by the Continental Congress on July 4, 1776, is above all a natural rights argument. Its opening appeals to 'the Laws of Nature and of Nature's God' as the basis for a people's separate and equal station. Its second paragraph sets out a chain of reasoning: all men are created equal; they are endowed with unalienable rights, including life, liberty and the pursuit of happiness; governments are instituted to secure these rights and derive 'their just powers from the consent of the governed'; and when a government becomes destructive of these ends, the people may alter or abolish it. Calling these truths 'self-evident' meant they were treated as first principles, known by reason rather than proved from something deeper. The long list of grievances against George III that follows was meant to show that this right of revolution applied in the colonists' case. The Declaration thus turned philosophical natural law into a public justification for independence.
- 50The American Mind: Sources of the DeclarationWhere did the ideas in the Declaration come from? In an 1825 letter, Thomas Jefferson said he had not aimed at originality but at 'an expression of the American mind', drawing on 'Aristotle, Cicero, Locke, Sidney' and others. Locke's influence is clear in the language of consent, a 'long train of abuses' and the right of revolution. A closer source was George Mason's Virginia Declaration of Rights, adopted on June 12, 1776, which stated that all men are 'by nature equally free and independent' and have 'inherent rights', including life, liberty, property and 'pursuing and obtaining happiness and safety'. Historians have also pointed to the Swiss jurist Jean-Jacques Burlamaqui, whose writings on natural law stressed happiness, and to Scottish moral philosophers. Scholars debate how much weight each source deserves. The safest conclusion is that the Declaration blended a widely shared natural rights tradition rather than copying any single author.
- 51Why 'the Pursuit of Happiness'?Locke had named life, liberty and property as natural rights, so why did the Declaration speak of 'the pursuit of happiness' instead? Historians offer several explanations. Locke himself had written of 'the pursuit of happiness' in his Essay Concerning Human Understanding (1690), describing it as the highest perfection of rational beings. Natural law writers such as Burlamaqui treated happiness as the purpose for which humans were made, and Mason's Virginia Declaration had already joined property with 'pursuing and obtaining happiness and safety'. In the eighteenth century, happiness often meant well-being and flourishing, including public happiness through participation in civic life, not just personal pleasure. Some argue that the change broadened the vision of rights beyond property; others suggest it was simply elegant wording reflecting common usage. The phrase signals that government exists not only to protect possessions but to secure the conditions for people to pursue a good life.
- 52Unalienable Rights: What Cannot Be Given AwayThe Declaration calls certain rights 'unalienable', meaning they cannot be transferred or surrendered, even voluntarily. This idea addressed a weakness in Grotius and Pufendorf, who had allowed people to give up their liberty to a ruler or master. The Scottish philosopher Francis Hutcheson argued in 1725 that some rights are inalienable because they cannot actually be transferred, such as the right of private judgment, or because transferring them serves no good purpose. Locke had made a related point: since people do not have absolute power over their own lives, they cannot give anyone else such power. If some rights are unalienable, then no contract, conquest or government can extinguish them, which supports a right to resist tyranny. Yet unalienable rights can still be limited: a person who commits a serious crime may lose liberty through due process. The concept asks a hard question: which rights belong to us so deeply that we cannot even choose to surrender them?
- 53All Men Are Created Equal: The Contradiction of SlaveryWhen the Declaration proclaimed that all men are created equal, roughly one in five people in the thirteen colonies was enslaved, and Jefferson himself enslaved hundreds of people over his lifetime. Contemporaries noticed the contradiction. In 1775 the English writer Samuel Johnson asked, 'How is it that we hear the loudest yelps for liberty among the drivers of negroes?' Jefferson's draft included a passage blaming George III for the slave trade, calling it 'cruel war against human nature itself', but Congress removed it, partly, Jefferson recorded, out of deference to South Carolina and Georgia. Historians interpret the contradiction differently: some stress hypocrisy and the protection of slaveholders' interests, while others emphasize that the Declaration's principles gave enslaved people and abolitionists a standard to hold the nation to. In 1791 the Black mathematician Benjamin Banneker wrote to Jefferson quoting the Declaration back to him. The gap between principle and practice became a driving force in American history.
- 54Natural and Imprescriptible: The Rights of Man in 1789On August 26, 1789, France's National Assembly adopted the Declaration of the Rights of Man and of the Citizen, another landmark natural rights text. Article 1 declares that 'men are born and remain free and equal in rights', and Article 2 names 'the natural and imprescriptible rights of man': liberty, property, security and resistance to oppression. Compared with the American Declaration, the French text is more general and universal in tone, addressed to 'man' everywhere rather than to one people's grievances. It also reflects Rousseau in calling law 'the expression of the general will', and it places sovereignty in 'the nation'. The Marquis de Lafayette, who helped draft it, consulted Thomas Jefferson, then the American minister in Paris. Philosophically, the two declarations share a core belief that rights precede government. They differ in emphasis: the American text justifies separation from a ruler, while the French text sets out principles for rebuilding an entire society.
- 55Burke's Critique of Abstract RightsThe Irish-born statesman Edmund Burke, who had defended the American colonists' grievances, became the most famous critic of the French Revolution's natural rights philosophy. In Reflections on the Revolution in France (1790), he argued that abstract 'metaphysic rights' drawn from reason alone were dangerous because they ignored the complexity of real societies. Rights, he said, are better understood as an inheritance, like the 'rights of Englishmen' secured gradually through Magna Carta, the Petition of Right and the Bill of Rights. Society, for Burke, is a partnership 'between those who are living, those who are dead, and those who are to be born', so reform should be cautious and build on tradition. He predicted that the Revolution's attempt to rebuild society from first principles would lead to disorder and, eventually, military dictatorship. Supporters see Burke as a founder of modern conservatism and a wise critic of utopian politics; critics say he defended privilege and undervalued the suffering that tradition concealed.
- 56Thomas Paine's Rights of ManThomas Paine, whose pamphlet Common Sense had urged American independence in 1776, answered Burke in Rights of Man (Part I, 1791; Part II, 1792). Paine argued that natural rights are those which belong to a person by the fact of their existence, such as freedom of thought, while civil rights are natural rights that people place in the common stock of society because they cannot secure them alone. He attacked Burke's reliance on precedent, insisting that each generation has the same rights as the one before and that 'the vanity and presumption of governing beyond the grave' is the most ridiculous of tyrannies. No generation, he said, can bind its descendants forever. Part II went further, proposing public support for the poor, the elderly and the education of children, paid for by taxes. Paine's writing was clear and aimed at ordinary readers, which alarmed the British government: he was tried in his absence for seditious libel in 1792 and convicted.
- 57Nonsense upon Stilts: Bentham Against Natural RightsThe English philosopher Jeremy Bentham (1748–1832) offered a very different critique of natural rights from Burke's. Bentham was a reformer who wanted sweeping changes to law, but he thought natural rights were confused. In Anarchical Fallacies, written in the mid-1790s as an attack on the French declarations, he declared: 'Natural rights is simple nonsense: natural and imprescriptible rights, rhetorical nonsense, nonsense upon stilts.' For Bentham, 'right is the child of law': real rights come from real laws backed by a real legislator, while 'natural' rights come from imaginary laws. He also feared that absolute rights language encouraged people to resist any law they disliked, inviting anarchy. Bentham proposed instead that laws be judged by utility, the greatest happiness of the greatest number. His critique laid foundations for legal positivism. Supporters of rights reply that utility can justify sacrificing individuals for the majority, which is exactly what rights are meant to prevent.
- 58Douglass and Lincoln: Appealing to the DeclarationIn the nineteenth century, opponents of slavery turned the Declaration's natural rights language into a weapon. On July 5, 1852, Frederick Douglass, who had escaped slavery, asked an audience in Rochester, New York, 'What, to the American slave, is your 4th of July?' He answered that it revealed 'the gross injustice and cruelty' to which the enslaved were subjected, yet he praised the Declaration's principles as 'saving principles' and expressed hope for the nation. After the Supreme Court's Dred Scott decision of 1857 claimed the Declaration's authors had not meant to include Black people, Abraham Lincoln argued that the founders 'meant to set up a standard maxim for free society', to be constantly approached even if never perfectly attained. In the Gettysburg Address of 1863, Lincoln dated the nation from 1776 and its proposition that all men are created equal. Both men treated the Declaration not as a description of reality but as a natural law standard against which the nation could be judged.
- 59The Declaration of Sentiments: Natural Rights for WomenIn July 1848, about three hundred people gathered at the Wesleyan Chapel in Seneca Falls, New York, for a convention on women's rights organized by Elizabeth Cady Stanton, Lucretia Mott and others. Stanton modeled their Declaration of Sentiments on the Declaration of Independence, declaring that 'all men and women are created equal' and endowed with unalienable rights. Instead of grievances against George III, it listed grievances against 'man', including denial of the vote, of property rights for married women and of access to education and professions. By borrowing the founding text's structure and natural rights language, the authors argued that America's own principles required women's equality. The resolution demanding the vote was the most controversial and passed only after Frederick Douglass spoke in its favor. One hundred attendees signed the declaration. The document shows how natural rights arguments could be extended to groups their original authors had excluded.
- 60Letter from Birmingham Jail: Natural Law and Civil DisobedienceIn April 1963, Martin Luther King Jr. was jailed in Birmingham, Alabama, for leading demonstrations against segregation in defiance of a court injunction. A group of eight local white clergymen had published a statement calling the protests 'unwise and untimely'. In his reply, the Letter from Birmingham Jail dated April 16, King drew directly on the natural law tradition. 'A just law is a man-made code that squares with the moral law or the law of God,' he wrote, while 'an unjust law is a code that is out of harmony with the moral law.' He quoted Aquinas and Augustine, and added that any law that degrades human personality is unjust. Yet King insisted that one who breaks an unjust law must do so 'openly, lovingly, and with a willingness to accept the penalty', showing respect for law itself. His letter is one of the clearest modern applications of natural law reasoning, joining ancient philosophy to nonviolent protest.
- 61What Is Legal Positivism?Legal positivism is the main rival to natural law theory. Its core claim, often called the separation thesis, is that whether a rule is law depends on social facts, such as whether it was enacted by a recognized authority in the right way, not on whether it is morally good. As the jurist John Austin put it, 'The existence of law is one thing; its merit or demerit is another.' Positivists do not claim that law should not be criticized; on the contrary, many, like Bentham, were reformers who thought clear thinking about what the law is made it easier to judge what it ought to be. Natural lawyers reply that a 'law' requiring grave injustice lacks the authority that makes law binding, so morality cannot be separated from legal validity entirely. Much of modern legal philosophy is an argument between these positions and attempts to find middle ground. Understanding the debate clarifies what judges, lawmakers and citizens mean when they call something 'the law'.
- 62Austin's Command Theory of LawJohn Austin (1790–1859) gave legal positivism its first systematic form in The Province of Jurisprudence Determined (1832), based on lectures at the new University of London. Austin defined law as a command issued by a sovereign, backed by the threat of a sanction. The sovereign is a person or body that the bulk of society habitually obeys and that does not habitually obey anyone else. On this view, a rule counts as law because of its source and the power behind it, not its content. Austin's theory was simple and appealing to reformers, but critics found serious problems. It struggles to explain laws that grant powers rather than impose duties, such as the rules for making a will. It also cannot easily explain why law continues when a monarch dies, or how constitutions limit lawmakers. Most famously, H. L. A. Hart argued that Austin's model made law look like 'the gunman situation writ large', missing the difference between being obliged and having an obligation.
- 63Marx's Critique of the Rights of ManKarl Marx challenged natural rights from a different direction. In 'On the Jewish Question', written in 1843 and published in 1844, he examined the French declarations of rights. He argued that the 'rights of man', such as liberty and property, were the rights of 'egoistic man', the individual separated from other people and from the community. Liberty, in this sense, was the right to do anything that harms no one else, which Marx saw as treating others as limits rather than partners. The right to property was the right to use one's possessions without regard to others. Marx distinguished 'political emancipation', winning equal legal rights, from 'human emancipation', a deeper transformation of social and economic life. Defenders of rights reply that legal rights have protected vulnerable people, including workers and dissidents, and that states which dismissed 'bourgeois' rights in Marx's name often violated them severely. The critique still prompts debate about whether formal rights are enough without social and economic conditions to use them.
- 64Hans Kelsen and the Pure Theory of LawThe Austrian jurist Hans Kelsen (1881–1973) sought a 'pure' theory of law, free from politics, morality, sociology and natural law. In his Pure Theory of Law (1934), he argued that law is a system of norms, each valid because it is authorized by a higher norm: a regulation is valid because a statute authorizes it, the statute because the constitution authorizes it. At the top sits the Grundnorm, or basic norm, a presupposition that the first constitution should be obeyed. Kelsen insisted that legal science must describe what the law requires without judging whether it is just. He was no defender of tyranny: he helped draft Austria's 1920 constitution, including one of the world's first specialized constitutional courts, and he was forced out of his post at Cologne by the Nazis in 1933. Critics argue that a theory which can describe any regime's commands as valid law gives no resources to resist injustice. Kelsen replied that judging law morally is important, but is a different task from describing it.
- 65H. L. A. Hart and the Concept of LawThe Oxford philosopher H. L. A. Hart (1907–1992) transformed legal positivism in The Concept of Law (1961). Rejecting Austin's commands, Hart argued that law is a union of primary and secondary rules. Primary rules impose duties, such as bans on violence. Secondary rules are rules about rules: a rule of recognition identifies which rules count as law, rules of change explain how laws are made and repealed, and rules of adjudication say who settles disputes. A legal system exists when officials accept the rule of recognition from what Hart called the 'internal point of view', treating it as a standard rather than merely predicting punishment. This explained features Austin could not, such as continuity when rulers change and laws that grant powers. Hart remained a positivist: a rule could be legally valid yet morally wicked. But he argued this clarity helped citizens see that the question 'Is this law?' is different from 'Must I obey it?'
- 66Hart's Minimum Content of Natural LawAlthough a positivist, Hart accepted that some truth lay in natural law. In The Concept of Law he described a 'minimum content of natural law': rules that any legal system must contain if it is to serve the basic aim of human survival. He grounded these not in divine reason but in simple facts about humans. People are vulnerable to bodily harm, so laws must restrict violence. They are approximately equal, so no one can dominate everyone for long without cooperation. Their altruism is limited, so rules are needed to curb selfishness. Resources are limited, so some form of property is necessary. And people have limited understanding and strength of will, so sanctions are needed to back rules for those tempted to break them. Hart's argument shows that the line between natural law and positivism is less sharp than it seems: even a positivist can admit that human nature shapes what any workable legal system must include, while still denying that injustice cancels legal validity.
- 67The Hart–Fuller DebateIn 1958 the Harvard Law Review published one of the most famous exchanges in legal philosophy. H. L. A. Hart, in an article based on his 1957 Holmes Lecture at Harvard, defended the separation of law and morals. He argued that calling wicked rules 'not law' blurs a hard moral question: it is clearer to say 'this is law, but too evil to obey'. Lon L. Fuller (1902–1978), a Harvard professor, replied in the same issue. Fuller argued that law is not simply any order backed by power, but a purposeful enterprise of 'subjecting human conduct to the governance of rules'. A regime that abandons this enterprise, he claimed, as the Nazis did through secret, retroactive and arbitrary measures, may cease to have a legal system worthy of fidelity. Both men were deeply concerned with how post-war Germany should deal with the legacy of Nazi rule. Their debate remains a standard starting point for students exploring whether law and morality can be separated.
- 68Fuller's Inner Morality of LawIn The Morality of Law (1964), Lon Fuller developed his reply to Hart with a parable about an imaginary ruler, King Rex, who fails to make law in eight different ways. Rex issues no general rules, keeps rules secret, makes them retroactive, writes them unclearly, makes them contradict each other, demands the impossible, changes them constantly, and acts in ways that do not match his own announced rules. From these failures Fuller derived eight principles of legality: generality, promulgation, non-retroactivity, clarity, non-contradiction, possibility of compliance, constancy and congruence between official action and declared rules. He called these the 'inner morality of law', because a system that ignores them entirely fails to be law at all. Critics, including Hart, objected that these are principles of efficiency rather than morality, since even a wicked regime could follow them. Fuller replied that respecting them treats people as responsible agents who can plan their lives, which is itself a moral commitment.
- 69The Grudge Informer Case and Its SourcesThe Hart–Fuller debate centered on a real dilemma from post-war Germany. In 1944 a woman, wishing to be rid of her husband, reported to the authorities remarks he had made criticizing Hitler. Under Nazi-era laws he was sentenced to death, though the sentence was not carried out and he was sent to serve at the front. After the war, in 1949, she was prosecuted in a West German court. Hart, relying on a brief English-language report of the case, said the court had convicted her on the ground that the Nazi statutes were contrary to the 'sound conscience and sense of justice of all decent human beings'. Hart argued it would have been more honest to pass a retroactive law openly punishing such informers. Later, in 1960, the scholar H. O. Pappe showed that the report had misdescribed the court's reasoning, which did not rely on declaring the statutes invalid in that way. The case teaches a lesson about sources: influential arguments can rest on flawed reports.
- 70Calder v. Bull: Natural Justice in an Early American CourtThe natural law–positivism debate appeared in the United States Supreme Court as early as 1798. In Calder v. Bull, the Court considered whether Connecticut's legislature could set aside a probate court decision about an inheritance, and ruled that the Constitution's ban on ex post facto laws applied only to criminal punishments, so the state's act stood. The case is remembered for two contrasting opinions. Justice Samuel Chase wrote that an act of the legislature 'contrary to the great first principles of the social compact' cannot be considered a rightful exercise of legislative authority, giving examples such as a law taking property from A and giving it to B. Justice James Iredell disagreed, warning that 'the ideas of natural justice are regulated by no fixed standard', since 'the ablest and the purest men have differed upon the subject'. Courts, he argued, should strike down laws only when they violate the written constitution. The exchange set the terms of a debate about judicial reasoning that has never ended.
- 71John Finnis and the Revival of Natural LawIn 1980 the Australian-born legal philosopher John Finnis published Natural Law and Natural Rights, written at the suggestion of H. L. A. Hart, his former teacher. The book revived natural law in analytic philosophy by reinterpreting Aquinas in modern terms. Finnis argued that certain basic goods are self-evidently worth pursuing: life, knowledge, play, aesthetic experience, friendship, practical reasonableness and religion, understood broadly as concern with the ultimate order of things. These goods are not derived from facts about human nature, he said, so the 'is–ought' objection misses its target. Finnis then set out requirements of practical reasonableness for pursuing these goods, and explained law as a way of coordinating a community's pursuit of the common good. He treated unjust laws as defective cases of law rather than as simply non-existent. Supporters credit him with making natural law philosophically rigorous again; critics question whether his list of goods is truly self-evident and dispute some of the moral conclusions he draws from it.
- 72Ronald Dworkin: Principles, Integrity and Rights as TrumpsThe American philosopher Ronald Dworkin (1931–2013), who succeeded Hart at Oxford in 1969, challenged positivism without adopting traditional natural law. He argued that law consists not only of rules but also of principles, such as 'no one should profit from their own wrong'. He pointed to Riggs v. Palmer (1889), in which a New York court refused to let a young man inherit from the grandfather he had murdered, even though the wills statute did not mention murder. For Dworkin, judges must interpret the law as a coherent whole that shows it in its best moral light, an approach he called 'law as integrity', personified by an ideal judge he named Hercules. He also described individual rights as 'trumps' that override collective goals such as general welfare. Positivists replied that principles can be identified by a rule of recognition after all. Dworkin's 'third way' shows that the debate about law and morality continues to evolve.
- 73When Injustice Wears the Form of Law: The Nazi StateThe Nazi regime posed the sharpest test of the natural law debate. Hitler's government came to power in 1933 and used legal forms to destroy the rule of law. The Enabling Act of March 1933 let the cabinet issue laws without the Reichstag. The Nuremberg Laws of September 1935 stripped Jewish Germans of citizenship and banned marriages between Jews and other Germans. Many of the regime's worst crimes, including the Holocaust, were organized through decrees, orders and bureaucracy. After the war, some argued that German lawyers had been trained to believe 'a law is a law' and so had no defense against wicked statutes. Historians have since complicated this claim: Nazi jurists often rejected strict positivism, and a 1935 amendment let judges punish acts by analogy with 'healthy popular sentiment' even where no statute applied. The episode shows that the danger lay not in one legal theory alone, but in abandoning the protections of law, such as clear, public and equally applied rules.
- 74Radbruch's Formula: When Statutes Lose Their ValidityGustav Radbruch (1878–1949), a legal philosopher who had served as Germany's justice minister in the Weimar Republic and was dismissed from his professorship by the Nazis in 1933, had long been close to positivism. After the war he changed his view. In a 1946 essay, 'Statutory Lawlessness and Supra-Statutory Law', he proposed what became known as the Radbruch formula. Normally, he said, enacted law should prevail even when it is unjust, because legal certainty is itself valuable. But where a statute's conflict with justice reaches an 'intolerable' degree, it must yield to justice; and where a statute deliberately denies the equality at the heart of justice, it lacks the nature of law altogether. The formula tried to keep the value of legal certainty while refusing to treat monstrous decrees as law. German courts applied it after the war, and again in the 1990s in cases against East German border guards who had shot people trying to cross the Berlin Wall.
- 75The Nuremberg Tribunal: Law Above StatesOn August 8, 1945, the United States, Britain, France and the Soviet Union signed the London Charter, creating an International Military Tribunal to try major Nazi leaders. The Charter defined three categories of crime: crimes against peace, war crimes and crimes against humanity, the last covering murder, extermination, enslavement, deportation and persecution of civilians. The trial opened at Nuremberg in November 1945. The American prosecutor Robert H. Jackson declared that four great nations, 'flushed with victory and stung with injury', had chosen to 'stay the hand of vengeance' and submit their enemies to the judgment of law. The tribunal's judgment stated that 'crimes against international law are committed by men, not by abstract entities', establishing that individuals could not hide behind the state. Of 22 defendants tried, 12 were sentenced to death and 3 acquitted. Critics called it 'victors' justice', noting that Allied conduct was not examined, but the trial laid foundations for modern international criminal law.
- 76Only Following Orders? The Superior Orders DefenseAt Nuremberg and later trials, many defendants argued that they had only been following orders from superiors whom they were legally bound to obey. If law is simply the command of a sovereign, this defense seems strong. But Article 8 of the London Charter declared that acting under orders 'shall not free him from responsibility', though it might be considered in reducing punishment. In 1950 the UN International Law Commission restated this as Nuremberg Principle IV: following orders does not relieve a person of responsibility, 'provided a moral choice was in fact possible to him'. This rule reflects a natural law insight: individuals retain a conscience that no command can override. Yet it also recognizes real pressures, since a soldier facing immediate death may lack a genuine choice. The defense was raised again by Adolf Eichmann in his 1961 trial in Jerusalem and rejected. Psychological research in the 1960s showed how readily ordinary people obey authority, which makes the principle both important and demanding.
- 77No Crime Without Law? The Retroactivity ProblemOne of the strongest objections to the Nuremberg trial invoked a principle that natural lawyers and positivists alike respect: nullum crimen sine lege, 'no crime without law'. People should not be punished for acts that were not crimes when committed. Defense lawyers argued that 'crimes against peace' had not been defined as individual crimes before the war. The tribunal answered that the maxim 'is not a limitation of sovereignty, but is in general a principle of justice', and that it would be unjust to let aggressors who knowingly broke treaties, such as the 1928 Kellogg–Briand Pact renouncing war, go unpunished. This was essentially a natural law argument: the defendants must have known their acts were deeply wrong. Critics, including Indian judge Radhabinod Pal at the Tokyo tribunal, argued that this undermined the very legality the trials claimed to uphold. Later human rights treaties tried to resolve the tension by allowing trials for acts criminal under 'the general principles of law recognized by the community of nations'.
- 78The Doctors' Trial and the Nuremberg CodeBetween December 1946 and August 1947, an American military tribunal at Nuremberg tried 23 defendants, 20 of them physicians, for medical experiments performed without consent on concentration camp prisoners and for involvement in killing programs. The defendants argued in part that no universal written rules governed human experimentation and that experiments elsewhere had also been conducted without consent. The judges responded by setting out ten principles for permissible medical experiments, now known as the Nuremberg Code. Its first and most famous principle states that 'the voluntary consent of the human subject is absolutely essential'. Other principles require that experiments aim at results for the good of society, avoid unnecessary suffering and allow subjects to withdraw. The Code drew its authority not from any statute but from what the judges presented as basic moral principles, a clear example of natural-rights reasoning about human dignity. Sixteen defendants were convicted and seven executed. The Code shaped later medical ethics worldwide.
- 79Natural-Rights Roots of the Universal DeclarationThe Universal Declaration of Human Rights, adopted by the UN General Assembly on December 10, 1948, drew on the natural rights tradition while deliberately avoiding any single philosophy. The drafting was led by the Commission on Human Rights, chaired by Eleanor Roosevelt. Canadian lawyer John Humphrey prepared the first draft; French jurist René Cassin reshaped it; Lebanese philosopher Charles Malik, influenced by Thomist natural law, stressed the dignity of the person; and Chinese diplomat Peng Chun Chang drew on Confucian thought and urged a document acceptable to all cultures. The text echoes the earlier declarations: its preamble speaks of the 'inherent dignity' and 'inalienable rights' of all members of the human family, and Article 1 says that all human beings are 'born free and equal in dignity and rights'. Yet the drafters spoke of 'human rights' rather than 'natural rights', so that people of many religions and philosophies could agree on the rights without agreeing on their ultimate source.
- 80Reason and Conscience: The Debate over Article 1Article 1 of the UDHR reads: 'All human beings are born free and equal in dignity and rights. They are endowed with reason and conscience and should act towards one another in a spirit of brotherhood.' Behind these words lay a careful debate about foundations. An earlier draft said human beings were endowed 'by nature' with reason and conscience, a phrase that suggested a particular philosophy. Some delegates wanted to mention God as the source of rights, as the American Declaration had; others, including delegates from officially atheist states, objected. The drafters removed both 'by nature' and any reference to God, leaving each reader free to supply their own foundation. The word 'conscience' is often said to reflect Peng Chun Chang's wish to express the Confucian idea of ren, a sense of shared humanity. The result is a statement that sounds like natural law but is philosophically open, which supporters see as wise inclusiveness and critics see as leaving rights without a firm grounding.
- 81Agreeing Without Asking Why: Maritain, UNESCO and GandhiWhile the UN Commission drafted the Declaration, UNESCO asked philosophers, religious leaders and writers around the world about the theoretical basis of human rights. The French Catholic philosopher Jacques Maritain, a leading modern interpreter of Aquinas, reported a striking result. Thinkers from opposed traditions could agree on a list of practical rights, but not on why people have them. As he put it, 'Yes, we agree about the rights but on condition that no one asks us why.' Maritain himself believed rights were grounded in natural law, yet he accepted that practical agreement could precede philosophical agreement. Mahatma Gandhi replied to UNESCO's inquiry with a different emphasis: from his 'illiterate but wise mother' he had learned that 'all rights to be deserved and preserved came from duty well done'. These responses show two lasting strategies: building rights on overlapping practical agreement, and reminding a rights-based world that duties and responsibilities matter too.
- 82From Nature to Dignity: A New Foundation for Rights?After 1945, the concept of human dignity largely replaced 'nature' as the stated foundation of rights. The UN Charter of 1945 reaffirmed faith in 'the dignity and worth of the human person'. The UDHR's preamble begins with 'the inherent dignity' of all members of the human family. Germany's Basic Law of 1949 opens with the words 'Human dignity shall be inviolable', a direct response to the Nazi era. The 1966 international covenants state that rights 'derive from the inherent dignity of the human person'. Dignity appealed to drafters because it could be accepted by religious believers, who might link it to creation, and by secular thinkers, who might link it to reason or autonomy. Critics argue that dignity is vague: the bioethicist Ruth Macklin wrote in 2003 that it often adds nothing beyond respect for autonomy. Defenders reply that its very breadth captures something the older language of nature also aimed at: the conviction that every person has a worth no law can erase.
- 83Jus Cogens: Norms No State May BreakModern international law contains an idea that looks strikingly like natural law. Article 53 of the 1969 Vienna Convention on the Law of Treaties declares that a treaty is void if it conflicts with a 'peremptory norm of general international law', also called jus cogens. Such a norm is one 'accepted and recognized by the international community of States as a whole as a norm from which no derogation is permitted'. Widely cited examples include the prohibitions of genocide, slavery, torture and aggression. Two states could not lawfully agree to enslave each other's citizens, however willingly they signed. Scholars debate how to understand this. Some see jus cogens as natural law returning in modern form, since it sets limits that even sovereign consent cannot override. Others stress that its definition rests on acceptance by states, making it a product of positive law. The concept shows that the old debate between natural law and positivism continues inside the structure of international law itself.
- 84Is There a Higher Law? Weighing the DebateFrom Antigone to the Universal Declaration, this course has followed one persistent question: is there a law above the laws that rulers make? Natural law thinkers answered yes, grounding it in reason, nature, God or human dignity, and used it to challenge tyranny, slavery and atrocity, from Las Casas to Douglass, King and the Nuremberg judges. Their critics raised serious objections: people disagree about what nature requires; 'natural' arguments have also defended slavery and inequality; and calling unjust laws 'not law' may blur clear thinking. Positivists offered clarity about what the law is, while many still admitted a 'minimum content' rooted in human nature. Modern law has blended both traditions: written constitutions and treaties now protect rights once claimed as natural, and concepts like jus cogens and dignity carry natural law's spirit in positive form. Evaluating this debate means weighing certainty against justice, and agreement against foundations, questions that every free society must keep asking.