One of the most significant thinkers who shaped Locke’s philosophy, despite preceding him by eighteen centuries, is Marcus Tullius Cicero.

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Paul Meany
Editor for Intellectual History, Lib​er​tar​i​an​ism​.org

Paul Meany is the editor for intellectual history at Lib​er​tar​i​an​ism​.org, a project of the Cato Institute. Most of his work focuses on examining thinkers who predate classical liberalism but still articulate broadly liberal attitudes and principles. He is the host of Portraits of Liberty, a podcast about uncovering and exploring underrated figures throughout history who have argued for a freer world. His writing covers a broad range of topics, including proto-​feminist writers, Classical Greece and Rome’s influence on the American Founding, ancient Chinese philosophy, tyrannicide, and the first argument for basic income.

John Locke is one of the most frequently cited philosophers in the classical liberal tradition. But while much has been written about Locke’s legacy, little has been written about those who influenced Locke’s work. Even the greatest genius does not work in a vacuum. We all borrow from others, whether consciously or unconsciously. One of the most significant thinkers who shaped Locke’s philosophy is Marcus Tullius Cicero, the famed Roman lawyer, statesman, and philosopher. Cicero influenced Locke’s thinking on natural law, property rights, and mixed government.

Cicero’s Life and Times

Cicero was born to a wealthy family in Arpinum, Italy, in 106 BC. Cicero was extensively educated in philosophy, even studying abroad in Greece. After completing his studies, he became a lawyer. He quickly became the most eloquent man in Rome, and his speeches show his flair combined with an adaptable, quick-​witted mind.

Cicero climbed the cursus honorum, the order of political offices held by aspiring politicians. Despite his family’s wealth, he was handicapped by his lack of noble ancestry, making him a novus homo, a “new man.” Despite this, Cicero held every office of the cursus honorum and even became a consul, the highest position in Rome’s political hierarchy, held by only two men annually. The zenith of his career came during his consulship when he thwarted a conspiracy to overthrow the Roman Republic by disgruntled politician Catiline. His speeches condemning Catiline are masterworks of oratory. For his efforts, he was awarded the title pater patriae, or “father of the fatherland,” the most outstanding achievement of his life.

The latter half of Cicero’s career was marked by his undying efforts to fight against the encroaching tyranny of Julius Caesar. Civil war erupted in 49 BC, and the Republic was thrown into chaos. Caesar eventually prevailed and made himself dictator of Rome. After Caesar’s assassination by a group of senators, Cicero attempted to restore order and quell the competition for power between Augustus and Mark Antony. After delivering a set of damning speeches condemning Mark Antony, Cicero was assassinated. Mark Antony chopped his hands off and nailed them to the rostra (a platform for public speakers) for all to see.

Unlike many of his contemporaries, Cicero left behind a large body of writing, including his legal and political speeches, letters to his best friend Atticus, and his philosophical writings. His work covers a vast breadth of topics, including arguments against redistributing lands, arguments for self-​defense, instruction on how to give convincing speeches, the nature of the Gods, old age, friendship, and a whole host of other topics.

Today, Cicero is rarely read by anyone besides students of the classics. For a long time, classical scholars believed there was little merit in reading Cicero as an original thinker. Throughout his philosophical writings, Cicero consistently peppers his work with quotations and anecdotes from an impressive number of Greek thinkers. This led many to believe that he had no original thoughts of his own and was, at best, an excellent vehicle to reconstruct the teachings of the lost philosophers from the Greek world. Thankfully, academics have begun to take Cicero seriously as an original thinker in his own right and to investigate his extensive influence on later thinkers.

One of Cicero’s most well-​read philosophical treatises is De Officiis (On Duties). This book was written in the last year of Cicero’s life. Although it was dedicated to his son, Cicero intended for De Officiis to have a much larger audience. Cicero’s wish was posthumously granted. Philosopher Martha Nussbaum has argued that De Officiis is one of the most influential books in Western political philosophy, and with good reason.

Many church fathers deeply admired Cicero and his avoidance of dogma. As Augustine wrote, “There are some people who use philosophy to lead people astray. … [T]he one thing that delighted me in Cicero’s exhortation was the advice to ‘not study one particular sect but to love and seek and pursue and hold fast and strongly embrace wisdom itself, wherever found” (Augustine 2008, p. 39). Throughout Thomas Aquinas’s masterwork, the Summa Theologica, he quotes Cicero numerous times. Renaissance Humanists attempted to recreate Cicero’s writing style throughout their works to an almost comical degree. De Officiis was the third book and the first classical text issued from the printing press. In the 17th century, little had changed. Rodger L’Estrange, a prolific pamphleteer and contemporary of Locke, exclaimed that De Officiis was “one of the commonest School Books that we have” (Marshall 1994, p. 167). Even in the 18th century, Cicero’s ideas were so commonplace that when Adam Smith quotes Cicero (which he often does), he does not bother to cite him as doing so would insult the reader’s intelligence. Thomas Jefferson wrote that the Declaration of Independence was influenced by what he called “the elementary books of public right,” which included Cicero and Locke.

Cicero was a massively popular author for more than a millennium. Throughout the history of political philosophy, Cicero held sway comparable to giants like Plato and Aristotle. However, Cicero differs significantly from his Greek predecessors and, in many ways, from most political philosophers. Many intellectuals have written impressive treatises on politics, but few have ever taken part in political life themselves. At times, this leads to overly idealistic, esoteric, or scholarly conclusions. Cicero was such an authoritative thinker for so long because he did not merely theorize about politics but practiced what he preached. It is a rarity for such a well-​read and scholarly person to also hold the reins of political power. John Adams, for whom Cicero was a personal hero, complimented Cicero by saying that “as all the ages of the world have not produced a greater statesman and philosopher united in the same character, his authority should have great weight” (Sellers 2003, p. 108). Cicero was no mere observer of political life; he actively participated until his death.

Locke’s Love of Cicero

Locke probably first encountered Cicero while he was attending Westminster as a boy. Throughout Locke’s early life, he used quotations from Cicero to add a sense of dignity and wit to his letters. However, this was not merely some teenage phase, as Locke’s love of Cicero lasted his entire life. By the time Locke had died, there were nine editions of De Officiis in his personal library. Locke also undertook a unique project in which he attempted to establish the chronology of Cicero’s life and work, a task he only attempted with one other person, Jesus Christ. Even contemporary classical scholars might have been surprised by Locke’s dedication to his study of Cicero.

In 1693, Locke wrote Some Thoughts Concerning Education, which was intended to be a treatise on the education of gentlemen. In this work, he discussed many niche topics at great length, such as how to toilet-​train a child and whether or not children should be allowed to eat certain fruits. However, when explaining what books a child should be given to read on moral conduct, Locke recommends only two books, the Bible and Cicero’s De Officiis. He also specifies that one should not give Cicero to a child solely to learn Latin but rather to “be informed in the Principles and Precepts of Virtue for the Conduct of his Life” (Forde 2013, p. 205). The original cover of An Essay Concerning Human Understanding is adorned with a Cicero quote from De Natura Deorum (On the Nature of the Gods). The epigraph for the Second Treatise is a quote from De Legibus.

Locke certainly admired Cicero. However, the critical question for classical liberals is: To what extent did Cicero affect Locke’s political thought?

Natural Law/​Rights, The Yardstick of Government

Cicero was a firm adherent of the natural law tradition. He believed there was a divine creator of the world who imbued rational beings with an objective set of laws by which to abide, not written physical laws but a code etched into the mind. To Cicero, natural law provides a standard by which to measure man-​made laws, which, he assures us, can never trump natural law. For Cicero, the widespread approval or acceptance of an act does not make it just. Nor is this law contextual to different nations or peoples; it is fixed and immutable. Cicero writes, “there will not be one such law in Rome and another in Athens, one now and another in the future, but all peoples at all times will be embraced by a single and eternal unchangeable law” (Cicero 2017, p. 69). The first and foremost principle of Cicero’s natural law is that “no man should harm another unless he has been provoked by injustice” (p. 9). Locke’s foundational principle of natural law closely resembles Cicero’s, “Being all equal and independent, no one ought to harm another in his life, health, liberty, or possessions” (Locke 1980, p. 9). Both believed that by their created nature, humans bear certain rights that no state authority cannot override. These laws, for both Locke and Cicero, are inherent in the nature of humanity. Even if no state existed to enforce these laws, they would still exist. Thus, the government is judged by how it conforms to natural law’s dictates.

Origins of Civil Society

If Cicero is correct that we already have a moral code that is discoverable by all beings, why do we even need a state to enforce rules? Cicero believes that we leave the state of nature and form states for three reasons: cooperation, inconvenience, and, most importantly, property. Locke shares all of these reasons for the state’s existence.

According to Cicero, the first people roved the wild, holding onto whatever property they could defend. Cicero believed men of virtue and wisdom convinced these primitive beings that it was advantageous to join together and to combine their collective abilities. Cicero argues for a kind of proto-​division of labor, listing the benefits of cooperation such as stable food, buildings, seafaring travel, irrigation, and trade. Locke has a not-​so-​coincidentally similar list of goods. Both Locke and Cicero believe that through a system of stable laws, which allow for peaceful cooperation, we can all achieve a great deal more material comfort than we would if we lived in the state of nature without cooperating.

Secondly, there is no justice system in the state of nature, and every man operates as their own judge, jury, and executioner. Cicero explains that this can lead to complications: “We do tend to notice and feel our own good and bad fortune more than that of others” (p. 13). We are biased towards our own interests, which may cause us to overstep our boundaries when resolving conflict. Locke explains that when one impinges upon another’s rights in a state of nature, the aggrieved party has the moral right to exact justice. However, this justice is not without limits and only stretches as far as calm reason and conscience dictate.

Locke agrees that without a system of laws, we would likely overreact in our pursuit of justice. This would provoke a cycle of revenge and lead to escalating violence. To avoid confusion and disarray, “all private judgment of every particular member being excluded, the community comes to be umpire, by settled standing rules, indifferent, and the same to all parties” (Locke 1980, p. 46). Unlike his contemporary Hobbes, who believed that we surrendered all of our natural rights when entering into a state, Locke believed we only surrendered one, our right to execute the law of nature. Instead, we yield this right to the community at large in order to create equitable and suitable laws that punish wrongdoers within reason.

Private Property

Many ancient thinkers, such as Plato and Aristotle, thought that the state’s end goal was to aid its citizens’ moral flourishing. This was not Cicero’s end goal; he is one of the earliest thinkers to extensively discuss the state’s role in protecting private property. Cicero believed “political communities and commonwealths were established particularly so that people could hold on to their property” (Cicero 2017, p. 92). He advises that the first and foremost duty of those who administer public affairs is to “see that everyone holds on to what is his, and that private men are never deprived of their goods by public acts.” Cicero accepts that no property is private by nature; however, “everything produced on the earth is created for the use of mankind” (p. 10). Despite explaining the importance of the state’s protection of private property at length, a glaring fault in Cicero’s writings is that he does not adequately explain how one comes to appropriate something as their property justly. At best, he reasons that convention, tradition, and harmony are adequate reasons for us to respect other’s private property.

Locke places a similar emphasis on the state’s role in protecting private property. He explains, “Government has no other end but the preservation of property” (Locke 1980, p. 51). Like Cicero, Locke believed that no property is private by nature, as he writes, “God, who hath given the world to men in common.” However, unlike Cicero, Locke explains that what makes property justly acquired is mixing one’s labor with the land. Every person owns themselves, and “every man has a property in his own person” (p. 19). When a person applies their labor to something in nature, it is no longer held in common but held privately by that person.

The Form of Government

Both Cicero and Locke believed that any form of government could at least theoretically be legitimated by conforming to the standards of natural law and acting to preserve people’s rights. However, both thinkers believed that there were systems that tended to fare better than others. What makes Cicero unique is that unlike many natural law theorists who articulate moral principles, Cicero was committed to figuring out what government can best preserve our natural rights.

Cicero believed there are three forms of simple government: monarchy, aristocracy, and democracy; the rule of the one, the few, and the many. Each of these forms has its own issues, which cause them to be defective and to decay into tyranny, oligarchy, or anarchy. To avoid this, Cicero believed that the best course of action was to have elements of each to balance the other out in a mixed form of government, which worked off of an early version of the separation of powers. Importantly, Cicero argued that all political authority is ultimately derived from the people. He based this upon the principle “let the welfare of the people be the ultimate law,” which was the epigraph of the Second Treatise on Government (and also, as it so happens, the motto of the state of Missouri). Cicero’s definition of a republic is, simply put, the property of the people, a state of affairs in which the people have a meaningful say in how the state is run. When sovereignty is not located in the people, tyranny quickly takes hold.

John Locke takes a similar approach by arguing in favor of a mixed government, which is different from Cicero’s in form but similar in principle. Locke argues that mixed government consists of legislative, executive, and federative powers. Legislative power, the ability to establish law, is made legitimate by the consent of the people. While this seems like a universally accepted principle to modern eyes, many of Locke’s contemporaries argued in favor of parliament as a supreme authority. Locke was consciously adapting Cicero’s definition of a republic as the common property of the people. A separate executive power guarantees that those who make the laws abide by their dictates. Lastly, federative power is the state’s ability to organize for the defense of the state. Both Locke and Cicero share an appreciation of the separation of powers, and both locate the sovereignty of the state with the people.

Resisting Tyranny

Cicero famously wrote, in De Officiis, about the justifiability of killing a tyrant. He argued that if a person or group of people were tyrannizing others, the people have the right to dispose of the tyrants as if they were wild beasts. He writes that it is similar to a situation where “the wildness and monstrousness of a beast appears in human form” and “it must be removed from the common humanity” (Cicero 2017, p. 111). The oppressed are not revolting; on the contrary, it is the tyrant who is rebelling against the immutable laws of nature. Simply because a law is written down does not confer its legitimacy, because “law in the proper sense is right reason in harmony with nature” (Cicero 2009, p. 68).

Locke similarly argues that since all people are naturally equal, no one has the right to initiate force against another. He writes, “Whenever the Legislators endeavor to take away, and destroy the Property of the People, or to reduce them to Slavery under Arbitrary Power, they put themselves into a state of War with the People” (Locke 1980, p. 111). Similar to Cicero’s wild beast analogy, it is not the people who are at fault but those who defied natural law. This dissolves any bonds and frees the people from “any farther Obedience.” With the bonds of civil society broken, each man regains the ability to execute natural law through self-​defense.

Cicero provides the foundation of Locke’s political thought. Locke’s theory of natural law, the origins of the state, the organization of government, and the right to revolution are all deeply indebted to an implicitly Ciceronian framework. But Locke is not a mere borrower. He further developed Cicero’s ideas by fleshing out his theory of property rights and focusing more on democratic ideals than Cicero, who favored aristocracies in many scenarios. This is not to say that Locke ever outgrew his Ciceronian roots; it was apparent to his contemporaries that Locke was a devout Ciceronian. The philosopher John Toland praised Locke, writing that “John Locke…must be confest to be greatest Philosopher after Cicero in the Universe” (Toland 1699, p. 147). The pairing of the two must have been deeply flattering to Locke.

Liberalism is usually conceptualized as a project of the Enlightenment, but the authors of the Enlightenment did not abandon the traditions and authorities of the past. On the contrary, they adapted them to their political purposes. In this vein, Cicero, as a learned man and lover of his country, was a tremendous authority to evoke. If Locke can accurately be called the father of liberalism, then, considering his debt to Cicero, it would not be unreasonable to dub Cicero the grandfather of liberalism.

Works Cited

Augustine. 2008. Confessions. Translated by Henry Chadwick. London: Oxford University Publishing.

Cicero, Marcus Tullius. 2017. On Duties. Edited by M.T. Griffin and E.M. Atkins. Cambridge, UK: Cambridge University Press.

Cicero, Marcus Tullius. 2009. The Republic and The Laws. Translated by Niall Rudd. London: Oxford University Press.

Forde, Steven. 2013. Locke, Science and Politics. Cambridge, UK: Cambridge University Press.

Locke, John. 1980. Two Treatises of Government. Indianapolis: Hackett Publishing Company.

Marshall, John. 1994. John Locke: Resistance, Religion and Responsibility. Cambridge, UK: Cambridge University Press.

Sellers, Mortimer. 2003. Republican Legal Theory: The History, Constitution and Purposes of Law in a Free State. London: Palgrave Macmillan.

Toland, John. 1699. The Life of John Milton. London: John Darby.