The Republic

Plato was in his early fifties when he wrote the Republic, around 375 BC. He was living in Athens and teaching at the Academy, the school he had founded about a decade earlier in a grove outside the city walls.

The book is one long conversation. In it Socrates, Plato's teacher, asks what justice is and whether a just person really lives better than an unjust one. To find out, he imagines a city built from scratch and ruled by philosophers.

Plato had good reasons to distrust real cities. He grew up during the long war that Athens lost to Sparta in 404 BC. After the defeat, a small group known as the Thirty seized power and ruled by terror, and two of them were his own relatives. Democracy returned the following year. Then, in 399 BC, an Athenian jury sentenced Socrates to death for disrespecting the city's gods and corrupting the young. So Plato had watched rule by the few and rule by the many both go wrong, and the second had killed the man he admired most.

In the Republic he brought Socrates back to life on the page. He also gave leading parts to his own brothers, Glaucon and Adeimantus, who press Socrates hardest. An ancient story says that after Plato's death a writing tablet was found with the opening sentence tried out in several word orders. The story may be legend, but it shows how carefully ancient readers believed he worked.

The book spread on papyrus rolls copied by hand. Its division into ten "books" probably reflects the length of those rolls, not Plato's own plan. Criticism came early and from close by. Aristotle, Plato's student, attacked the proposal that the city's rulers should hold property and families in common.

Others borrowed from it. Cicero, the Roman statesman, wrote his own dialogue on the state in imitation. In the twelfth century Averroes, a Muslim philosopher from Córdoba, wrote a commentary on it. Western Europe had few readers of Greek in the Middle Ages, so the text returned there only in the fifteenth century, through Latin translations. The version by Marsilio Ficino, a Florentine scholar, was printed in 1484. A generation later, the English statesman Thomas More drew on it for his Utopia.

The quarrel is still open. In 1945 the philosopher Karl Popper accused Plato of preparing the ground for totalitarian rule, because the ideal city censors its poets and rests on a founding myth its rulers know to be false. Meanwhile the image of the cave, where prisoners take shadows on a wall for reality, remains one of the first things philosophy students meet.