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Plato's Republic
c. 375 BC· Book or text· Politics, society & justice
Well documentedSolid records, texts or physical evidence.
Plato's ten-book dialogue on justice, which designs an ideal city ruled by philosopher-kings to show what a just soul looks like.
See it on the Philosophy map →The idea
It opens with Thrasymachus claiming justice is 'the advantage of the stronger', and Glaucon's Ring of Gyges: would anyone stay honest if invisible? Socrates answers by building an ideal city with three classes, rulers, soldiers and producers, matching the soul's three parts, reason, spirit and appetite. Justice is each part doing its own job under reason. The rulers are philosophers who own no property, and women can rule too. Poets are censored, and democracy ranks just above tyranny.
Why it matters
It is the founding text of Western political philosophy and the model for later utopias; every argument about who should rule still answers it.
Where it comes from
The complete Greek text survives in medieval manuscripts; style places it in Plato's middle period, around 375 BC. Aristotle's Politics criticizes it by name.
Still debated
Whether Plato meant the city as a real blueprint or a thought experiment about the soul; Karl Popper (1945) read it as a charter for totalitarianism.
Inside this (1)
Connections (5)
▸Trial and death of Socrates fed Plato's distrust of democracy in Plato's RepublicDebated
The connection
Plato watched a democratic jury, swayed by speeches, condemn to death the best man he knew. In the Republic he argues that ruling is a skill, like navigating a ship, and that crowds pick leaders by flattery, not expertise. The freed prisoner of the Cave, whom the others would kill, recalls Socrates' fate.
When and how
Athens, between 399 BC and about 375 BC; Plato wrote the Republic roughly 25 years after the execution.
How sure are we?
The Seventh Letter says the execution turned Plato away from politics, but its authenticity is disputed; the parallels in the Republic are suggestive, not proof.
Debates and open questions
Plato's distrust of democracy may owe as much to his aristocratic family, his relatives among the Thirty Tyrants, and Athens's war defeat as to the trial.
▸Plato wrote Plato's RepublicWell documented
The connection
Plato wrote the Republic in mid-career as a long Socratic conversation that pulls his ideas together: justice, the soul's three parts, the Forms, education, the philosopher-ruler, and the decline of governments. Socrates narrates, but the system is generally read as Plato's own.
When and how
Athens, around 375 BC, about a decade after he founded the Academy; the conversation is set in Piraeus, the port, during the Peloponnesian War.
How we know
Its authenticity has never been seriously doubted; Aristotle's Politics discusses it by name, and studies of Plato's style place it in his middle period.
Debates and open questions
Book I differs in style from the rest and may first have been a separate dialogue; the exact date of composition is unknown.
▸Plato's Republic contains The Allegory of the CaveWell documented
The connection
The Cave comes in Book VII, right after the Sun and Divided Line analogies, as the third picture of how the mind rises from opinion to knowledge. Plato uses it to explain why future rulers need long philosophical training, and why, once enlightened, they must go back down and govern.
When and how
Republic Book VII (514a–520a), told by Socrates to Plato's brother Glaucon, written around 375 BC.
How we know
It is in the text itself; Socrates says explicitly that the image should be fitted to what was said earlier about the Sun and the Line.
Debates and open questions
Why would freed philosophers agree to return to the cave? Plato says justice requires it, but many readers find the answer thin.
▸Plato's Republic asks What is justice?Well documented
The connection
The Republic is built as one long answer. After Thrasymachus says justice serves the strong, and Glaucon asks whether anyone would stay just if invisible, Socrates argues that justice is a harmony in which each part of the city and of the soul does its proper job, and that the just person is the happiest.
When and how
Books I–IV and IX of the Republic, around 375 BC; the challengers are Thrasymachus and Plato's brothers Glaucon and Adeimantus.
How we know
The dialogue's ancient subtitle, 'On Justice', and its structure, question in Book I, answer in Book IV, final defence in Book IX, make the link explicit.
Debates and open questions
Critics since antiquity ask whether Plato changed the subject: inner harmony of the soul may not be what ordinary people mean by treating others justly.
▸Niccolò Machiavelli, The Prince broke with the idealism of Plato's RepublicWell documented
The connection
Plato designed an ideal city ruled by philosophers who know the Good. Machiavelli rejected that approach outright: in chapter 15 of The Prince he dismissed 'republics and principalities that have never been seen', choosing instead 'the effectual truth of the matter'. Politics, he argued, must start from how people actually behave.
When and how
Florence, 1513, written on his farm near San Casciano; Marsilio Ficino's complete Latin translation of Plato had been printed in Florence in 1484.
How we know
The famous rejection is in chapter 15; Machiavelli does not name Plato, but scholars widely read it as aimed at Plato and the idealizing tradition he started.
Debates and open questions
Whether the target was Plato specifically, or the Christian and humanist advice books for princes in general, is debated.