Law in Roman Philosophy

Legal philosophy in late antiquity must be understood in relation to Roman law, a system which continued to evolve from the traditional founding of Rome (753 B.C.) until the fall of the Eastern Roman (or Byzantine) Empire (A.D. 1453). ¹Rome was at first ruled by kings about whom little is certain. A set of laws attributed to them (leges regiae) and compiled by Papirius a priest (pontifex) were probably statements of customary and religious norms, concerning marriage, family relations, funeral rites, and so forth (Johnson, Coleman-Norton, and Bourne 1961, 3–6). The Roman Republic (509–27 B.C.) was initially threatened by internecine conflict between the patrician and plebeian orders. This was resolved in part through the Twelve Tables (451–450 B.C.), a written public code composed by officials called decemviri, which could not be arbitrarily changed by patrician magistrates. This collection of statutes, which the Roman historian Livy called “the fount of all law, public and private” (Roman History 3.34.6, trans. Jones), was lost, although many quotations, paraphrases, and descriptions were preserved by later Roman authors (Johnson, Coleman- Norton, and Bourne 1961, 9–18; Warmington 1967; see also A. Watson 1975).

The republican constitution had three elements: the magistrates, the senate, and the assemblies. The important magistrates (most holding office for a year) included the two consuls, praetors (both of whom held a coercive power termed imperium, which entailed a judicial capacity), aediles (whose general concern was maintenance of public order through adherence to regulations), quaestors (whose responsibilities were largely financial), and censors (in charge of census and supervision of morals). In emergencies, usually on the advice of the senate, a magistrate with imperium could nominate a dictator who, if approved by the senate, would hold supreme imperium for at most six months. The senate (literally “council of elders”) had a purely advisory role based on auctoritatas, a morally binding authority, but it eventually became the dominant political body. Ideally, it had 300 members (later 600) who were mostly former magistrates and had lifelong tenure. Among the various assemblies, the oldest was the curiate (comitia curiata), composed of thirty curiae, which ratified the Twelve Tables but gradually lost importance. The most powerful assembly was the centuriate (comitia centuriata), organized into classes based on wealth as an index to military capacity, which elected magistrates such as the consuls with supreme power (imperium) and had the right to declare war or ratify treaties. The tribal assembly (comitia tributa) elected lower magistrates and adjudicated some non-capital cases. Finally, to help resolve their conflict with the patricians, the plebeians formed their own assembly (concilium plebis), presided over by ten tribunes, which gradually became an important legislative body. The tribunes acquired increasing power, including the right to veto the proposals of magistrates and fellow tribunes. These assemblies underwent changes. For example, the patrician and plebeian membership of the tribal assembly gradually melded with the purely plebeian membership of the plebeian assembly, so that the tribal assembly became the dominant legislative and electoral body in republican Rome.

Every adult male citizen was a member of the curiate, centuriate, and tribal assemblies, and every plebeian (the vast majority of citizens) had a right to membership in the plebeian assembly. Although all citizens could vote, their votes were tallied in groups, whether curia, tribe, or century (the last weighted in favor of wealthy citizens who could afford to arm themselves more fully). The Romans recognized different sources for law (ius, pl. iura). In the Republic, a measure approved by an assembly was called a statute (lex, pl. leges). The acts of the plebeian assembly (called plebiscita) had the force of law binding on all citizens after the enactment of the Hortensian statute of 287 B.C. An assembly’s powers were limited, because it could not initiate legislation. It could only approve or reject a measure placed before it by a magistrate, which had been previously discussed and approved by the senate. These resolutions could be vetoed by a tribune or a magistrate with imperium before the assembly had the opportunity to act on them. The edicts proclaimed by magistrates were also regarded as laws. In some instances, these edicts served to confirm resolutions of the senate (senatus consulta).²

Jurists (iuris consulti or prudentes) also played an important role in the development of Roman law (see Lenel 1889; Frier 1985; Bauman 1971; and Johnston 2000). Originally priests but later normally former magistrates, they were legal experts who advised the praetor as members of his council. Some jurists wrote widely circulated manuals, including Quintus Mucius Scaevola (consul in 95 B.C. and author of an influential treatise on civil law), his pupil Aquilius Gallus (praetor in 66 B.C.), Servius Sulpicius Rufus (consul in 51 B.C.), and Alfenus Varus (interim consul 39 B.C.). There was also a school (secta or schola) in the senate that discussed legal issues. The jurists wrote answers to legal questions (responsa prudentium) concerning the interpretation of laws and official edicts. They also assisted in the drafting of legal documents such as contracts and wills, and they advised judges and disputants in lawsuits. Their opinions were embodied in court decisions which served as precedents for later decisions. The jurists influenced the interpretation of the unwritten (non scriptum) law or custom (mos, pl. mores), which, like the Greeks, the Romans distinguished from written (scriptum) law.

The historian Polybius (ca. 200–ca. 118 B.C.) viewed the Roman constitution as the true exemplar of the “mixed constitution,” combining monarchical, aristocratic, and democratic elements:

[I]t was impossible even for a native to pronounce with certainty whether the whole system was aristocratic, democratic, or monarchical. This was indeed only natural. For if one fixed one’s eyes on the power of the consuls, the constitution seemed completely monarchical and royal; if on that of the senate it seemed again to be aristocratic; and when one looked at the power of the masses, it seemed clearly to be a democracy. (Polybius, Histories VI.11.12, trans. Paton)

Within the Roman Republic, as described by Polybius, each branch has distinct powers: The consuls are the supreme magistrates, especially in matters of war; and they summon assemblies, introduce measures, and preside over the execution of decrees. The senate controls public finance, investigates public crimes such as treason, conspiracy, and assassination, and is in charge of embassies to foreign countries. The popular assemblies have sole constitutional authority (kurios) over the imposition of honors and punishments and to bestow offices. Also, writes Polybius, “the people have the power [kurian] of approving or rejecting laws [nomôn], and what is most important of all, they deliberate on the question of war and peace” (Histories VI.14.10, trans. Paton). The three parts of the constitution are each able, if they wish, to counteract and cooperate with the others in various ways. For example, although the people are obliged to be submissive and deferential to the senate (VI.17.1), the assemblies can curb the traditional authority (exousia) of the senate and the tribunes can prevent it from acting (VI.16.3–4). Polybius admires the Roman system involving separated powers with checks and balances: “Such being the power that each part has of hampering the others or cooperating with them, their union is adequate to all emergencies, so that it is impossible to find a better political system than this” (Histories VI.18.1, trans. Paton).

Polybius was the friend and teacher of Scipio Aemilianus, a powerful politician and the general who destroyed Carthage. Scipio shared Polybius’ ideal of the Roman balanced constitution, but feared its eventual decline. This ideal was increasingly jeopardized by the division between the rich and the poor, which was reflected in disputes within the Roman ruling class itself between the so-called populares (who tended to rely on tribunes and the tribal and plebeian assemblies) and the so-called optimates (who tended to rely on the senate and magistracies). The political order was shaken by a series of crises, including the attempt of the tribune Tiberius Sempronius Gracchus to institute land reform through the plebeian assembly and bypass the senate, leading to his assassination (133 B.C.). His reforms were continued by his brother, Gaius Sempronius Gracchus (d. 121 B.C.), one of whose laws required that juries be selected from the equites (cavalry). Although this was meant as a populist measure, it had the unintended consequence of empowering the publicani (tax collectors) as an interest group and exacerbating political instability. L. Cornelius Sulla used an army to have himself appointed dictator with unspecified tenure (81–79 B.C.). A succession of violent conflicts among powerful holders of imperium, including Marius, Pompey, Julius Caesar, Marc Antony, and others finally brought down the Republic.

Marcus Tullius Cicero (106–43 B.C.) was an influential figure during this tumultuous period. Scion of an affluent but not politically established family, he studied law under the jurist Mucius Scaevola and gained personal influence through his rhetorical skill and successes in the law courts. A supporter of optimate tactics, Cicero defended the Roman Republic as a mixed constitution without parallel. He studied philosophy in Athens, consorted with Greek intellectuals in Rome, and popularized Greek philosophy among his compatriots. Late in life, forced to withdraw from politics, he wrote dialogues dealing with legal philosophy, including On Duties, On the Commonwealth (with Scipio Aemelianus as an interlocutor), and On the Laws, the latter two modeled after Plato’s dialogues. He criticized the traditional jurists for concentrating on particular laws, for example, “about water running off roofs or about shared walls,” and neglecting questions about the source of law and justice (Leg. I.14). (His views are discussed in Section 6.​2 below.) After the assassination of Julius Caesar (44 B.C.), Cicero reentered politics only to be killed on order of his nemesis Marc Antony, who was in turn defeated by Caesar’s nephew, Octavian, who, as Caesar Augustus, gained constitutional control of the state in 27 B.C. Despite his claim that as “first man” (princeps) he had restored the republic, Augustus was in fact the first Roman emperor.

The history of the empire has two main periods: the principate (27 B.C.– A.D. 284) and dominate (A.D. 284–585).³ During the early principate, legal authority shifted increasingly to the emperor to whom the people had committed its “entire authority and power” (Justinian, Dig. I.4.1). Legislation by assembly gave way to imperial enactment (constitutio), and the last statute (lex) was passed under the emperor Nerva (ruled 96–98). At first the emperor relied on the senate to approve his proposals, but this procedure became increasingly perfunctory and finally ceased. Nevertheless, there was considerable interest in the law during this period. During the reign of Augustus there arose two contending legal schools (intellectual movements, not educational institutions) in the senate: the Proculians and the Sabinians. Since the former school (founded by Labeo, a critic of Augustus) challenged the more traditional view of the latter (under Capito), there ensued vigorous debate over jurisprudence. Augustus granted certain jurists the right to give answers with the force of law (ius respondendi), although this practice died out during the second century A.D. The emperors increasingly relied on edicts, legal decisions, and rescripts (written answers to queries by officials). The power of the jurists in the senate waned under Emperor Hadrian (117–138), but one of his rescripts did establish that the concurrent written opinion of privileged jurists had the force of law, although a judge could use his discretion if the jurists’ opinions disagreed.

During the first two centuries of the Roman Empire, Stoic philosophers made important contributions to legal thought. These included, most notably, the statesman and dramatist Seneca (1–65), the freed slave Epictetus (60–140), and the emperor Marcus Aurelius (b. 121, ruled 161–180). (They are discussed in Sections 6.3–5 of this chapter.)

Throughout the course of the Roman Empire, there continued, however, to be considerable scholarly interest in jurisprudence (see Honoré 1994).⁴ Many ancient treatises on this subject have unfortunately perished, although numerous excerpts were preserved in Justinian’s Digest (see Chapter 10, Section 10.​1, of this volume). In the first century A.D., Masurius Sabinus published Three Books on Civil Law, a collection of opinions of jurists. Like other scholars, he distinguished civil law (ius civile), which applied only to Roman citizens, from the law of nations (ius gentium), that is, Roman law concerning cases involving foreigners and Romans (as in international commerce). He also distinguished different kinds of civil law—law of succession, law of persons, law of obligations, and law of things—an approach followed by later writers. Many collections of juridical opinions circulated during the first three centuries A.D., including the Epistulae of Proculus (mid-first century) and of Neratius Priscus (d. after 133), the Digesta of Julian (second century), the Digesta and other works of Celsus (second century), the Enchiridion of Pomponius (second century), the Quaestiones and Responsa of the highly revered Papinian (d. 212), the Institutes of Marcian (early-third century), and the many works of Paul (d. after 235), fragments of which were later collected in the extant Sententiae or Opinions. Of special interest to modern legal scholars is the Institutes of Gaius (ca. 160), of which a manuscript was discovered in 1816.⁵ The only work of a jurist to survive substantially intact, it covers the law of persons, property rights and inheritance, and legal actions. Ulpian (d. 228), perhaps the most influential of the jurists, published a Digest and numerous other works with many citations of his predecessors. The extant Epitome was a later compilation of excerpts from his writings.⁶ The last of the great jurists was Herrenius Modestinus (third century). The Vatican Fragments (mid-fourth century) is a valuable extant collection of extracts from Papinian, Paul, and Ulpian, as well as later rescripts and opinions. Also surviving is the Mosicarum et Romanarum Legum Collatio (composed between ca. 390–438), which compares Roman law with Mosaic law, quoting legal experts (on Mosaic law see Chapter 7, Section 7.​1, of this volume).

These authorities tended to be scholars and editors rather than original legal thinkers. But their works were widely read and often cited in legal decisions. Some of them (e.g., Proculus, Neratius Priscus, Celsus) favored the more rigorously principled Proculian viewpoint, and others (e.g., Masurius Sabinus, Cassius Longinus, Julian, Gaius) favored the more traditional and pragmatic Sabinian position. Their differences in legal philosophy resulted in disagreements on some particular issues, for example, on whether the price of something must be pecuniary (Proculians) or can consist in other goods as in barter (Sabinians) (see Gaius, Inst. III.140–1). Some of them, especially Gaius, Paul, and Ulpian, were strongly influenced by the discussions of nature and law in Aristotle and the Stoics, although they understood these concepts differently. For example, Gaius generally follows Aristotle’s treatment of law and justice, including his distinction between the natural and the legal. Gaius distinguishes civil law, “which each people makes for itself” and is “peculiar to itself,” from the law of nations (ius gentium), which is common to all peoples: “The law which natural reason makes for all mankind is applied in the same way everywhere.” Gaius here suggests that commonality of legal practice is evidence of its reasonableness. Differences of civil law reflect local conventions that were in effect different ways of implementing general principles (e.g., that promises are binding). Gaius expresses a Roman legal viewpoint that supported toleration of different local legal systems. According to Gaius, natural reason also reveals natural law (as in the case of the right of first acquisition), so that the law of nations is, in effect, equivalent to natural law (Inst. I.1, II.65–6; cf. Justinian, Dig. I.1.9; see Honoré 1962, chap. 6). Ulpian, in contrast, sharply distinguishes these concepts:

Private law is tripartite, being derived from principles of natural law, law of nations, or civil law. Natural law is that which nature has taught to all animals; for it is not a law specific to mankind but is common to all animals […]. Out of this comes the union of man and woman which we call marriage, and the procreation of children, and their rearing […]. The law of nations is that which all human beings observe. That it is not co-extensive with natural law can be grasped easily, since this latter is common to all animals whereas the law of nations is common only to human beings among themselves. (Ulpian, Inst. I ap. Justinian Dig. I.1.1)

Using this distinction, Ulpian reasons, for example, that slavery and consequently manumission belong to the law of nations, “since, of course, everyone would be born free by the natural law” (Ulpian, Inst. I ap. Justinian Dig. I.1.4; cf. 3–4). Ulpian agrees here with other jurists such as Tryphoninus (Disputations VII ap. Justinian Dig. XII.6.64) and Florentinus (Institutes XII ap. Justinian Dig. I.5.4) (see Carlyle 1936, vol. 1: 39). Unfortunately, the crucial distinction between natural law and the law of nations is not further clarified in the surviving texts of the jurists. Nor do they explain their use of the term “natural,” which seems to be used for what they regard as normal or reasonable (Levy 1949, 7; Kelly 1992, 57–63).

Concerning the concept of law, the jurists drew on Greek orators and philosophers in an eclectic way. Marcian quotes Demosthenes and Chrysippus. Drawing on Demosthenes, he mentions three reasons why everyone ought to obey law: “It is a discovery and a gift of god”; “it is a resolution of wise men, a correction of misdeeds both voluntary and involuntary”; and “it is the common agreement [sunthêkê] of the polis according to whose terms all who live in the polis ought to live.” Papinian echoes this view, when he defines a statute (lex) as a “resolution of wise men” and “a communal covenant of the state” (Definitions I ap. Justinian Dig. I.3.1). Marcian also appeals to Chrysippus, “a philosopher of supreme Stoic wisdom”: “Law is king over all divine and human affairs. It ought to be the controller, ruler, and guide of good and bad men alike, and in this way to be a standard of justice and injustice and, for beings political, by nature a prescription of what ought to be done and a proscription of what ought not to be done” (Marcian, Institutes ap. Justinian Dig. I.3.2, trans. Watson). Ulpian expresses a similar view, closely connecting law (ius) and justice (iustitia): Legal wisdom (iuris prudentia) “is an awareness of God’s and men’s affairs, knowledge of justice and injustice” (Rules I ap. Justinian Dig. I.1.10). Ulpian also remarks, somewhat obscurely, that civil law neither follows wholly nor diverges entirely from natural law or the law of nations, and that it is made by adding to or taking away from the common law (Inst. I ap. Justinian Dig. I.1.6). The surviving writings of the jurists have little else to say concerning the nature of law.

During the dominate (starting A.D. 284) the emperors wielded absolute political power. The later empire came to resemble an oriental despotism with the emperor as a god or, after the triumph of Christianity, God’s representative on earth. Deprived of independent authority, the jurists devolved into mere advisors to the emperor who possessed the ultimate legislative authority. Nonetheless, the emperors and citizens alike recognized the lack of, and pressing need for, a comprehensive and consistent system of laws that would apply throughout the empire. At the beginning of this period, the Gregorian Code (ca. 291) and the Hermogenian Code (ca. 295), named after two officials of the Emperor Diocletian (reigned 284–305), undertook to systematize the rescripts of emperors.⁷ In an effort to resolve the many inconsistencies in the extant legal literature, Emperor Theodosius II laid down the Law of Citations (426), which involved the following decision procedure: Follow the writings of Papinian, Paul, Ulpian, Modestinus, and Gaius; and secondarily follow other jurists cited by them. If these five disagree, follow the majority. If there is no majority, follow Papinian. If Papinian says nothing on the issue, the judge may use his own discretion. Finding this procedure insufficient, the emperor promulgated the Theodosian Code (438), which sought to combine the previous codes, laws, and juridical opinions into a consistent statement of public law (see Mommsen and Meyer 2002–2005; Pharr 1952; Harries and Wood 1993; Harries 1999). Laws were dated, with later laws given precedence. The law of citations was retained for citations of the jurists. The code itself was divided into sixteen books, of which the last eleven have survived in manuscripts. Material from the other books was preserved in later works, especially the Justinian Code (528–555), the Lex Romana Visigothorum (506), and other legal codes of the Germanic barbarians. After the end of direct Roman rule in much of western Europe, the history of Roman legal thought continued in Constantinople, the New Rome.⁸

There is little original philosophy of law in ancient Roman thought, if “philosophy of law” is understood in a narrow sense to designate a field distinct from political philosophy. But, for whatever reason, legal concepts enjoyed an extensive and vital use in the philosophical discourse of this era. The exploitation of “law” and various legal concepts is especially associated with Stoicism. This is not without reason, although Platonism had a very important influence on Roman legal thought (as did, to a lesser extent, Aristotelianism and Epicureanism).⁹ The authors most characteristic of Roman legal philosophy— Cicero, Seneca, Epictetus, and Marcus Aurelius—will be the focus of the rest of this chapter. Particular attention shall be paid to what is regarded as their most important contribution to legal philosophy: the idea of natural law.¹⁰

In the philosophical tradition it was Plato who first brought “law” and “nature” into fruitful philosophical contact (see Chapter 3 of this volume). Early Stoicism pushed these ideas even further, in ways that remain controversial among scholars (see Inwood 1999; Vander Waerdt 1994c; and Chapter 5, Section 5.​6 of this volume).¹¹ Natural law (or the “common law,” koinos nomos, the better attested term for early Stoics) is the perfected rationality of Zeus and the sage, giving orders about what is to be done and what is not to be done, orders whose content is one of two sorts. First, the common law commands that rational agents act virtuously, in accordance with their perfected reason and nature. These commands are immune to exception when left at this level of generality, but they are not definitively action-guiding since the virtuous thing to do is often to be determined by variable circumstances. Second, this law also provides more concrete guidance about how one should act by specifying the kinds of things one should do in particular circumstances. But once it does this, it loses the immunity from exception that characterizes the broad injunctions to act virtuously. A natural law, then, is always imperatival; but if universal it will be to some extent vague, and if definite enough to be action-guiding it will admit of exceptions (cf. Inwood 1999). This is a perfectly reasonable application of a conception of law to philosophical thinking: It reflects a general truth about the relationship between laws or rules and moral behavior (a truth which Aristotle recognized when discussing equity in its relationship to laws), namely, by their very nature laws have a vagueness that demands flexible interpretation if the underlying purpose of attaining justice is to be achieved.

These Stoic ideas influenced Cicero (b. 106 B.C.), the Roman statesman and philosopher whose career spanned the most turbulent years of the late republic. He was first elected to public office in 75 B.C., won the consulship in 63 B.C., and was preoccupied with the constantly decaying condition of the republic until his murder in 43 B.C. by the minions of Marc Antony. His early education included a thorough study of Greek philosophy, and he continued to read and write philosophical works throughout his life. The two works of Cicero that matter most to the present discussion are On the Commonwealth and On the Laws, which were composed during the 50s B.C. when Cicero was effectively deprived of political power yet constantly yearning to preserve the old Roman Republic of his ideals, one characterized by the enlightened leadership of a stable elite and by a high degree of social cohesion.¹² These works were part of a Ciceronian project to emulate Plato in a Roman context; Plato’s

Republic and Laws were the obvious models for Cicero when he conceived these works.¹³

These are the first works of distinctively Roman philosophy of law which demand our attention. In On the Commonwealth Cicero presents us with a wide-ranging debate about the best constitution, arguing that the traditional Roman manner of organizing a state is the closest to an ideal that one can achieve. In this debate a spokesman for Academic skepticism is the foil for both Stoic natural law theory (which argues that justice has a uniform foundation in nature) and Epicurean conventionalism (which holds that justice is a function of utility in varied human societies). Cicero’s sympathy for the natural law position is manifest.¹⁴ But we must also take notice of the fact that at least in On the Laws the Stoic character of the theory is ambivalent. No matter how much sympathy Cicero had for Stoicism and despite his use of characters whose persona is Stoic, these works are emulations of Plato, and Cicero is himself an Academic by inclination as well as by choice. One of his teachers in the Academy, Antiochus of Ascalon, argued for the essential harmony of early Academic, Peripatetic, and Stoic philosophy, and Cicero could not avoid being influenced by this view—though it is a position which most members of those schools would have vigorously rejected.

The Stoic influence on Cicero can be seen in his inclusion of a translation of the famous proem to On Law by Chrysippus in his own On the Laws I.18, though it is highly significant that throughout this work Cicero attributes Stoic ideas not to the school nor even to philosophers, but to “learned men.” Where Stoics are explicitly mentioned, it is in a discussion of the demarcation disputes between various Socratic schools and the importance of focusing on their common ground (Leg. I.53–6).¹⁵ Overall, the flavor of the books is heavily Platonic (as witnessed by the allusion to recollection at I.25) and for whatever reason Cicero has chosen to conceal the level of Stoic influence (see Inwood 2003).¹⁶

Hence, it is difficult to distinguish with confidence the Ciceronian themes we can claim for the Stoics and those which we cannot—except where there is independent evidence that a given idea is Stoic (as indeed there is on many points). This indeterminacy with regard to the filiation of much of the argument, as well as the sketchy nature of what Cicero says here, help explain why these works have played a less prominent role in the large and well-aired debates about the nature of natural law in Stoic thought.

It may seem peculiar to claim that On the Laws gives us a sketchy account of natural law, but this claim can be substantiated by looking at the text. First, though, the following general assessment made by Vander Waerdt should be invoked: Cicero’s twin goals in On the Laws were to “reformulate Stoic doctrine on natural law so as to make it practically useful, and to reformulate the [Roman] ius civile so as to bring it into conformity with this modified Stoic theory” (Vander Waerdt 1994a, 4867). He also maintains that this project was unique and uniquely uninfluential. Vander Waerdt’s concern is to show that the Ciceronian project was uninfluential with regard to Roman jurisprudence, but it is just as true that it remained relatively unimportant in later ancient philosophy whether written in Latin or Greek. While the now fragmentary On the Commonwealth had a powerful impact in antiquity, just the opposite is the case for On the Laws. Zetzel’s suggestion (1999, xxi; see also Atkins 2000) is surely right: Cicero never completed the latter book, left off work on it in 51 B.C., and did not think it appropriate to publish it during his lifetime. Left incomplete—in part because changing political circumstances sapped his motivation and in part because he was likely unable to solve serious problems with the consistency and intellectual cohesion of the work as it stood in 51 (cf. Atkins 2000, 501–2)—the work was published posthumously and left to relative neglect for centuries.

In both On the Commonwealth and On the Laws the central idea is not that “law” in any narrow or well-defined sense is grounded in nature. What matters far more to Cicero is the claim that justice is natural. This is certainly the central point that emerges from On the Commonwealth, where Cicero explains what natural law offers us in contrast to human law:

[The wise man] alone can truly claim all things as his own, not under the law of the Roman people but under the law of the philosophers; not by civil ownership but by the common law of nature, which forbids anything to belong to anyone except someone who knows how to employ and use it. (I.27)

This is a clear reflection of one of the Stoic paradoxes—that all things belong to the wise man, or that only the wise man is wealthy—and we should conclude that one purpose of the Stoic postulation of an ideal cosmopolis is to provide a city in which the paradoxical claims about the wise man are true. Later in the book (I.48–9) Cicero repeats the traditional idea that law is the bond that holds a society together, and suggests that the necessary condition for an ideally stable society is equality under the law. These themes are familiar from earlier Stoic and Cynic thought and ultimately stem, no doubt, from Plato’s Republic.

The claim that justice exists by nature rather than by potentially variable human convention is explored at greatest length in On the Commonwealth III, and it is this idea which we associate most readily with Cicero’s treatment of natural law.¹⁷ The principal philosophical claim, as far as philosophy of law is concerned, is that the naturalness and objectivity of moral virtues, including justice, follows from some law-like feature of the natural order of things. The debate played out in Book III is important for political philosophy, but it seems that almost nothing in it turns on any conception of law. As with the earlier Stoics and with Plato, Cicero adorns an argument for natural justice in terms of “law” language; but the dress is paper thin.

The more definite claim that there is a natural foundation for specific laws (as opposed to the general institutions of justice) is distinct and far more difficult to defend. It is this claim which comes to the fore in On the Laws, especially in Book II. This is a hard position to defend, in part because of the commitment Cicero makes to connect his broad claims about the virtue of justice and a “utopian” natural law (expressed in Stoic terms) with the specific constitutional arrangements of the state sketched in On the Commonwealth. That he does take on this commitment in On the Laws is indicated by the following:

Then since we want to preserve and protect that form of the commonwealth which Scipio showed was the best in the six books of On the Commonwealth, and since all the laws must be fitted to that type of state, and since morals must be planted and we should not rely on the sanctions of written laws, I will seek the roots of justice in nature, under whose leadership our entire discussion must unfold. (I.20, trans. Zetzel)

Moreover, the exposition of particular laws in On the Laws II–III is prefaced by a recapitulation of the utopian conception of natural law as nothing but the perfected practical rationality (in the commanding rather than the theoretical mode) of the wise person or the gods, buttressed by a repetition of the claim that any law which is subject to amendment or abrogation is eo ipso not a law at all.

The claim that there is a natural law, then, in contrast to the much more general and less challenging claim that there is a natural foundation for justice (and other virtues, too, as a result—see Leg. I.42–3) is one of two things. Either it is the claim that there is a divine law which is the perfected rationality of the gods, Zeus, or a perfected human mind (I.18–19, 21–7)—what we might call a Chrysippean conception of natural law, since Cicero is clearly translating the proem to Chrysippus’ On Law and drawing on Stoic definitions when he identifies law with recta ratio (orthos logos, “right reason”)—or it is the claim that there are laws found in and constitutive of a polity that are grounded in nature via their relationship to the perfect divine law of gods and sages.

To see how sketchy the notion of natural law is in this text, we should consider the options more closely. If by the natural law we mean the perfected rationality of Zeus commanding what ought to be done and forbidding what ought not to be done—that is, the Chrysippean notion of natural law—then we discover in the course of On the Laws I and the proem to Book II that its content seems to consist in the virtues and the pursuit of true Socratic utility by perfection of our rational nature and harmonization of it with the divine nature of the cosmos. Hence, its commands would be the sorts of injunctions to act virtuously which are insufficiently action-guiding and hence, from the point of view of legal requirements, more or less vacuous.¹⁸ But if we mean by natural law the detailed and contentful specific arrangements given in the rest of On the Laws, which are indeed laws that would fit nicely with the kind of state sketched in On the Commonwealth, then the problem for Cicero is acute. Are any of the laws which he gives in those books the sorts of permanent, invariant, unamendable, and irrevocable laws which he claims any law must be, on pain of not being any sort of law at all (Leg. II.13–14), antedating any written or even conventional instantiation in society (II.8, 10–11, I.19)? No one reading the “laws” of Cicero will claim that these provisions for the idealized republic of Cicero’s historical imagination meet this standard.

What we get, then, in On the Laws