Latin had no word for "quality". It had no word for the moral as a field of study, and none for the ideal of human cultivation the Greeks argued about. A Roman who wanted to think seriously read Greek, argued in Greek and quoted Greek; a Roman who did not read Greek was simply shut out of the conversation. Cicero ended that in roughly two years, while shut out of politics himself. He minted qualitas and quantitas, made moralis the name of a field, and gave humanitas the sense — a cultivated humanity — that it carried afterwards; and Europe did its thinking in those words for the next fifteen hundred years.
Nothing in his career pointed there. He came from Arpinum, a hill town sixty miles from Rome, from a family that had never produced a consul, and he reached the consulship in 63 BCE on speech alone. Five years later that consulship destroyed him: he had executed the Catilinarian conspirators, Catiline's followers in a plot to overthrow the Republic, without trial, the tribune Clodius, a personal enemy, passed a law aimed at exactly that, and Cicero fled Italy. His house on the Palatine, the hill where wealthy Romans lived, was pulled down and a shrine to Liberty raised on the ground, which under Roman religious law made the site permanently unbuildable. He came back, argued the consecration invalid on procedure, and got his ground.
The philosophy came out of a second defeat, one he could not argue his way out of. Caesar won the civil war, and the senate Cicero had spent thirty years persuading no longer decided anything. In February 45 his daughter Tullia died after childbirth. He wrote a consolation addressed to himself — the work is lost. In those same two years, 45 and 44, he also produced the Academica, De Finibus, the Tusculan Disputations, De Natura Deorum, De Divinatione, and finally De Officiis, written as a letter to his son. He was explicit about the cause: the forum was closed, so he wrote.
He wrote as a sceptic, which is the part most often missed. He had heard Philo of Larissa, head of Plato's Academy in its sceptical phase, lecture at Rome, and he took from the Academy the conviction that certainty is not available and that the honest procedure is to argue a question from both sides and settle for the more probable answer. So his dialogues put the Stoic case and the Epicurean case, two of the great rival schools of the day, at full strength and frequently decline to rule between them. The method cost him his standing as a thinker for centuries: a man who states everyone's position and endorses none looks, to a reader in a hurry, like a man with nothing of his own.
What was his own was the strongest claim he made. In De Re Publica he argued that there is one law, the same at Rome and at Athens, discoverable by reason and binding on every people at every time — and that no senate and no assembly can vote it away. Legality and justice are not the same thing, and a properly enacted law can be a crime. That claim runs through Lactantius, an early Christian writer, and Aquinas into the Dutch jurist Grotius, Locke and the American founding documents.
Antony, Caesar's former lieutenant, had him proscribed — declared an outlaw whom anyone might kill. He was caught near Formiae on 7 December 43 BCE, and his head and his hands — the hands that wrote the Philippics, fourteen speeches against Antony — were nailed to the speakers' platform in the forum.
The afterlife was uneven. De Re Publica survived only in fragments quoted by Lactantius, Augustine and Nonius, a late Roman grammarian; one section, the Dream of Scipio, came through whole because Macrobius, a writer of the early fifth century, had built a commentary around it. Then in 1819 a quarter of the text resurfaced in a Vatican manuscript whose pages had been scraped clean and written over with Augustine on the Psalms. De Officiis, meanwhile, was among the first classical texts ever printed, at Mainz, Gutenberg's city, in 1465. In the nineteenth century Mommsen, the great German historian of Rome, called him a statesman without insight or purpose and a short-sighted egotist; that verdict ruled the lecture halls for a hundred years and is now in open retreat. Specialists no longer argue over whether Cicero counts as a philosopher; they argue over how much of the philosophy in him is his.