Marcus Tullius Cicero was one of history’s most celebrated orators. He exerted a profound influence on the development of classical liberal and libertarian thought. In large measure because the beauty of his Latin prose led to its preservation into the modern age, Cicero’s ideas about natural law and justice were preserved and transmitted to medieval Europe from classical antiquity. Cicero was born in Arpinum, a town about 70 miles south of Rome. As a youth, he studied rhetoric, jurisprudence, and philosophy. (His earliest work, De Inventione, is based on his study of the art of rhetoric.) He made his mark in law and politics as a novus homo (a “new man,” not descended from one of Rome’s great families).
Cicero was deeply involved in Roman politics. In 75 B.C., he was elected quaestor in Sicily and became a member of the Roman Senate. In 70 B.C., he successfully prosecuted Gaius Verres, former governor of Sicily, for corruption, a proceeding that made Cicero famous for his legal and oratorical abilities. In 66 B.C., Cicero was elected praetor, and in 63 B.C., he was elected to the consulship, in which office he prosecuted Catiline and the other conspirators for attempting to overthrow the Roman Republic. Cicero became known as a central defender of the institutions of the Roman Republic against those who sought to establish their personal rule. He made many enemies during his political career and was eventually murdered in 43 B.C. on orders from Mark Antony; his severed head and hands were ordered nailed to the rostrum in the Roman Forum.
His philosophical writings transmitted to medieval writers and to the modern world many of the ideas that originated in the works of Aristotle, of the Stoics, and of other writers of Greek and Latin antiquity. Especially notable for their influence on political thought was the idea of a universal human nature and of a law of nature to govern mankind. In De Officiis (On Duties, 44 B.C.), he argued that,
if nature prescribes that one man should want to consider the interests of another, whoever he may be, for the very reason that he is a man, it is necessary, according to the same nature, that what is beneficial to all is something common. If that is so, then we are all constrained by one and the same law of nature; and if that is also true, then we are certainly forbidden by the law of nature from acting violently against another person.
Such concern about the interests of other people extends not only to fellow citizens, but to all of mankind: “There are others … who say that account should be taken of other citizens, but deny it in the case of foreigners; such men tear apart the common fellowship of the human race.” In DeLegibus (The Laws, written between 52 and 43 B.C.), he affirmed that, “howsoever one defines man, the same definition applies to us all,” and articulated the idea of a universal legal order. Those ideas, both directly and indirectly, deeply influenced the tradition of natural law that informed classical liberalism and libertarianism.
Cicero. On Duties. M. T. Griffin and E. M. Atkins, eds. Cambridge: Cambridge University Press, 1991.
———. The Republic and the Laws. Niall Rudd, trans. Oxford: Oxford University Press, 1998.