Plato's Republic: Justice, the Tripartite Soul, and the Philosopher-King

The Republic (Greek Politeia, Latin Res publica) is the longest and most influential work of Plato (c. 428/427–348/347 BCE) and, by broad consensus, one of the founding texts of Western political philosophy, ethics, and the philosophy of education. Probably composed around 375 BCE, in what is conventionally called Plato’s middle period, it is presented as a dialogue narrated by Socrates in the first person, recounting a conversation held at the house of Cephalus in the Piraeus. The question that drives the book can be put simply: what is justice, and why is it better to live justly than unjustly? To answer it, Plato builds in words an ideal city and, in parallel, a theory of the soul, a theory of knowledge, and a theory of education.

This article follows the work in order, with Stephanus references (the pagination of Henri Estienne’s 1578 edition, which became the standard way of citing Plato). For the metaphysics of the Forms and the famous allegory of Book VII, the reader will find a full treatment in another article on this site: The Allegory of the Cave and the Theory of Forms. For Plato’s place within the Greek tradition, see Socrates, Plato, Aristotle: the founding triad of Greek philosophy.

Context and structure of the ten books

The division into ten books is the traditional one. In outline:

The exact boundaries of each block vary among commentators, but these ranges match the usual divisions of editions and scholarly summaries.

Book I: Cephalus, Polemarchus, and Thrasymachus

Book I has the form of Plato’s early “Socratic” dialogues: it ends in aporia. Cephalus, a wealthy old man, suggests that justice consists in telling the truth and paying one’s debts (331c). Socrates objects with a simple counterexample: returning weapons to a friend who has gone mad would be unjust (331c). Cephalus’s son and heir to the argument, Polemarchus, then defends a definition he attributes to the poet Simonides: justice is giving each what is owed, which means benefiting friends and harming enemies (331e–336a). Socrates shows that harming someone makes him worse, and that making others worse cannot be the work of virtue.

At this point the sophist Thrasymachus bursts in (336b). His thesis is that justice is nothing other than the advantage of the stronger (338c): every regime lays down laws for its own benefit, and calling obedience to them “just” amounts to obeying the interest of the rulers. Socrates replies, among other arguments, that a ruler in the strict sense is like a craftsman whose art aims at the good of what it governs, not at his own (341c–342e). He adds that injustice, wherever it appears, produces discord and prevents joint action (351b–352c), and that justice is the proper virtue of the soul, what enables it to perform its function (ergon) and live well (352d–354a). At the end of the book he himself admits that the discussion has not established what justice is (354b–c). The problem stays open for the rest of the work.

The challenge of Glaucon and the Ring of Gyges

Dissatisfied with the refutation, Plato’s brothers Glaucon and Adeimantus reopen the question in Book II (357a). Glaucon sorts goods into three kinds: those we want for their own sake, those we want both for themselves and for their consequences, and those we want only for their consequences. Where does justice belong? Common opinion puts it in the third class, a burden tolerated for the sake of rewards and reputation (357b–358a). To make the position stronger than Thrasymachus himself made it, Glaucon offers a contractualist account of the origin of justice: it is a compromise between the wish to do injustice with impunity and the fear of suffering it (358e–359b).

To illustrate, he tells the story of Gyges, a shepherd in the service of the king of Lydia, who after an earthquake finds in a chasm in the earth a ring that makes him invisible (359d–360b). With it Gyges seduces the queen, kills the king, and seizes power. Glaucon’s argument is a thought experiment: if there were two such rings, one worn by the just man and one by the unjust, no one would be so adamantine as to remain just (360b–d). The just and the unjust would act alike. Justice would be a convention observed from lack of power, not something desirable in itself.

Glaucon then adds the comparison between the perfectly unjust man who enjoys a reputation for justice and the perfectly just man who bears a reputation for injustice (360e–362c). Adeimantus supplements this: parents, poets, and teachers praise justice for its rewards, not for itself (362d–367e). The brothers’ challenge asks Socrates to show that justice is good in itself, independently of reputation and prizes. The whole work, through Book IX, is the answer to that demand.

From city to soul: the just city and the guardians

Socrates’ strategy is one of enlargement: just as letters are easier to read when written large, justice will be easier to see in the city than in the individual (368c–369a). This grounds the city–soul analogy that organizes the rest of the work.

The city arises from need: no individual is self-sufficient, and the division of labor makes each person more efficient at his own task (369b–370c). Glaucon scorns this first city, calling it a “city of pigs” (372d), and Socrates moves on to the “luxurious” or “feverish” city (372e ff.), which, being expansionist, needs an army. Here the class of guardians (phylakes) emerges, who must combine the spiritedness of a watchdog with gentleness toward their own (375a–376c).

The guardians’ education occupies Books II–III and VII. It comprises music (in the broad sense, including literature) and gymnastics (376e–412b). In the musical part, the censorship of myths and poetry that portray gods and heroes unworthily (377a–398b) is the first move in the critique of poetry that will be resumed in Book X. The guardians are also placed under unusual rules of life: no private property and common meals (416d–417b); and, for the guardian class, women educated and employed in the same tasks (451c–457b) and a community of wives and children (457c–461e), with the declared aim of removing sources of division within the ruling class.

The best guardians, chosen by tests of loyalty to the good of the city (412b–414b), become the rulers (archontes), and the rest become auxiliaries (epikouroi). To ground the social order, Socrates proposes the so-called “noble lie” (gennaion pseudos, 414b–415d): a myth according to which all citizens are born of the earth and are brothers, but were formed with different metals (gold, silver, bronze, and iron) and must occupy the places that correspond to their nature. It is one of the most debated points in the work and returns below in connection with Popper’s reading.

The four cardinal virtues and the tripartite soul

In Book IV the city has been sketched, and Socrates can look in it for the four virtues that later tradition would call cardinal (427d–434c). (The term “cardinal” is later, of Latin origin; in Plato they appear as the four virtues of a “perfectly good” city, 427e.)

• Wisdom (sophia): knowledge of what is good for the city as a whole; it resides in the smallest class, the rulers (428b–429a).
• Courage (andreia): preserving, despite pleasures and fears, the correct opinion about what is to be feared; it resides in the auxiliaries (429a–430c).
• Moderation or temperance (sōphrosynē): a kind of order and mastery over pleasures and desires; it differs from the others in not residing in a particular class but in being an agreement among all classes about who should rule (430d–432a).
• Justice (dikaiosynē): what remains once the other three have been found, namely that each class perform its own task and not meddle in the tasks of others (ta heautou prattein, 433a–b; 434c).

The decisive step comes next. If justice is the same in city and soul, the soul must have corresponding parts. Socrates argues from the principle of conflict: one and the same thing cannot, at the same time and in the same respect, undergo or do contrary things (436b–c). Since the same soul can desire to drink and yet refuse to drink, it must contain distinct parts (437b–439d). The result is the tripartite soul:

1. the rational part (logistikon), which loves learning and calculates what is best;
2. the spirited part (thymoeides), seat of anger, honor, and ambition; its distinction from appetite is illustrated by the case of Leontius, who feels disgust with himself for wanting to gaze at corpses (439e–440a);
3. the appetitive part (epithymētikon), seat of the desires of the body (437b–439d).

Justice in the soul is the condition in which each part performs its function: reason rules, aided by thymos, and appetite, the largest part in quantity, is ruled (441c–444a). Plato compares it to health: justice is a natural order among the parts, and injustice is like disease (444c–445b). Note that this is an “inner” justice, in which what counts is not external conduct but the constitution of the soul that produces it (443c–444a). This is how Socrates answers Glaucon’s challenge: the just person is happy by virtue of his own constitution, not because he is rewarded.

The philosopher-king

In Book V, Glaucon and the others press Socrates for explanations of the community of women and children, and Socrates answers with three “waves” (kymata), that is, three proposals he expects to provoke storms of mockery: equal education and functions for women and men among the guardians (451c–457b), the community of families (457c–466d), and, the most radical, the philosopher-king (473c–e).

The thesis is formulated thus: the evils of cities, and of the human race, will not cease until philosophers rule as kings or those now called kings and potentates philosophize genuinely and adequately, that is, until political power and philosophy coincide in one subject (473c–d). To justify the thesis, it is necessary to show what a philosopher is (474b–480a). Here Plato distinguishes the lover of spectacles (philotheamon), who delights in particular beautiful things, from the lover of wisdom, who loves the Beautiful itself; the former lives in doxa (opinion) and the latter possesses epistēmē (knowledge), a theme also discussed in the article Doxa and Episteme. Book VI resumes the qualities of the philosophical nature (484a–487a), and the allegory of the ship of state (488a–489a) is meant to show why philosophers look useless to cities: the crowds and the captains, as on a ship, do not recognize the pilot’s art.

The philosopher does not rule from desire for power. Plato holds that the best rulers are those who least wish to rule (520d–521b), and that after the ascent to the Good the philosopher must “descend” again into the cave to fulfill his task (519c–521b). The pedagogy preparing such a ruler is long: at twenty, a selection; then ten years of mathematical sciences; at thirty, five years of dialectic; then fifteen years of practical office; and only at fifty the final encounter with the Good (537b–540c). Philosophical education corresponds to what the tradition calls paideia, discussed in Philosophy of education.

Sun, Line, and Cave: the epistemological summary

Between the end of Book VI and the start of Book VII, Plato presents the three images that ground the philosopher’s claim to rule. In brief:

• The sun (506d–509c): just as the sun is the cause of visibility and growth in the sensible world, the Form of the Good is the cause of the intelligibility and being of the Forms, itself “beyond being” (epekeina tēs ousias, 509b).
• The divided line (509d–511e): four grades of reality and knowledge, from imagination (eikasia) and belief (pistis), which belong to the domain of opinion, to discursive thought (dianoia) and intellection (noēsis), which belong to the intelligible domain.
• The cave (514a–521b): the common human condition as captivity among shadows, the difficult ascent to knowledge, and the duty of return.

The detailed exposition, the interpretive debate, and the relation to the Theory of Forms are found in the article devoted to the Allegory of the Cave. Here the essential point is their role in the structure of the Republic: they show why only one who knows the Good is qualified to rule, and why the justice of the city cannot be separated from the order of knowledge.

The decline of regimes (Books VIII–IX)

Having defined the just city and the just soul, Socrates resumes, at the start of Book VIII, his promise to examine the four defective forms of constitution and the corresponding human types (543a–545c). The scheme links each regime to a type of soul and describes a sequence of degenerations:

1. Aristocracy (the ideal city) or kingship, ruled by reason.
2. Timocracy (545c–550c): the regime of honor and ambition, like Sparta and Crete, in which the spirited part dominates; the timocratic man is ambitious and loves victory.
3. Oligarchy (550c–555b): a regime in which wealth is the criterion of power; the city divides into rich and poor; the oligarchic man is an accumulator who satisfies only necessary desires.
4. Democracy (555b–562a): it arises from the oligarchs’ insatiable desire for wealth and the revolt of the poor; its principle is freedom, expressed in the license to live as one likes (557b); the democratic man treats all desires as equal and lives from moment to moment (558c–561e).
5. Tyranny (562a–569c): it arises, in Plato’s account, from an excess of freedom that turns into an excess of servitude (564a). The demagogue who presents himself as protector of the people becomes a tyrant.

In Book IX Socrates describes the tyrannical man, dominated by an unbridled desire (571a–576b), and concludes that the tyrant is the most wretched of men (576b–580c). He then offers three arguments that the just life is more pleasant than the unjust one (580d–588a) and, finally, the image of the soul as a composite of a many-headed beast, a lion, and a human being (588b–589b). The just city, Socrates observes, is a model “laid up in heaven” (en ouranō paradeigma, 592b) that anyone can take as a pattern for ordering himself, whether or not it exists anywhere on earth.

It should be stressed that the scheme is not an empirical historical theory but a moral and psychological typology. Plato describes democracy with the irony of one who reads in it a regime of variety and apparent beauty (557c), and his judgment is partly explained by Athenian experience: Socrates, his teacher, was condemned to death by a democratic jury in 399 BCE. For Plato’s conception of justice compared with those of Aristotle and Rawls, see Justice: Plato, Aristotle, Rawls.

The critique of poetry (Book X)

Book X resumes, with metaphysical arguments, the censorship of poetry begun in Books II and III. Socrates declares that imitative poetry must be excluded from the city (595a). The argument draws on the theory of Forms: there is the Form of the bed, the particular beds made by the carpenter, and, third, the bed painted by the painter, which is an imitation (mimēsis) of an appearance; the imitator is therefore three removes from truth (596a–598d). The tragic poet falls under the same critique: he does not know what he talks about but merely produces images. Moreover, poetry, by representing the passions, feeds the irrational part of the soul and weakens reason (603c–606d). Hence the reference to the “ancient quarrel between philosophy and poetry” (607b).

Plato nevertheless leaves a door ajar: defenders of poetry may be readmitted if they show in argument that it benefits both the city and human life (607c–608b). On the concept and its afterlife, see the glossary entry Mimesis and the article Beauty and philosophical aesthetics.

The Myth of Er

The work closes with an eschatological myth (614b–621d). Er, son of Armenius, from Pamphylia, died in battle and, twelve days later, as his body lay on the funeral pyre, returned to life and told what he had seen (614b). The souls of the dead are judged; the just ascend to heaven and the unjust descend beneath the earth, receiving punishments and rewards ten times greater than the deeds committed (615a–b). After a thousand years the souls arrive at a meadow and there see the shaft of light that spans the heavens and the spindle of Necessity (Ananke), with the Fates Lachesis, Clotho, and Atropos (616b–617d).

The philosophically central point is the choice of lives (617d–620d). A spokesman of Lachesis announces that no divinity will assign each soul its lot, since each will choose its own, and that responsibility lies with the chooser: the god is blameless (617e). The first soul to choose, who came from heaven and was accustomed to an orderly, virtuous life but lacked philosophy, opts for a great tyranny without noticing that it contains terrible evils (619b–d). Animal souls choose human lives and vice versa; and the soul of Odysseus, which chose last, weary of the ambitions of its previous life, picks the quiet life of an ordinary man (620c–d). Before rebirth, all souls, on the plain of Lethe (forgetfulness), drink from the river Ameles (Heedlessness), except Er (621a–b).

The myth serves several functions: it confirms that justice is rewarded, but it also reinforces the thesis that what matters is the capacity to distinguish good lives from bad, the task that philosophical education prepares. The work ends with the exhortation that, holding to the upward way and practicing justice with wisdom, readers will be dear to themselves and to the gods, both here and on the thousand-year journey (621c–d). Because it is a myth, the text does not offer an assertoric doctrine of immortality; the argument for the immortality of the soul comes earlier, at 608c–611a.

Reception and criticism

Aristotle

The first systematic critic was Plato’s most famous student. In the Politics (Book II, chs. 1–5), Aristotle examines the city of the Republic and raises objections that became classic. He argues that the unity Plato wants for the city is excessive: a city is by nature a plurality, and extreme unity would destroy it (1261a). He criticizes the community of wives and children, holding that what is common to many receives least care (1261b) and that affection grows watery when everyone is “mine” in equal measure (1262a–b). He rejects the abolition of private property among the guardians (1263a–b) and observes that the perpetual rule of the same persons breeds discontent (1264a–b). In ethics, the critique of the Form of the Good as a universal principle is in the Nicomachean Ethics I.6 (1096a–1097a), and it is linked to the general critique of the Forms in the Metaphysics I.9. See also Aristotle: Nicomachean Ethics.

Later readings

The tradition is unanimous neither in its judgment nor in its view of the genre of the work. Rousseau, in Émile (Book I), considered the Republic less a political writing than the finest treatise on education ever composed. Hegel, in the preface to the Elements of the Philosophy of Right, recognized in Plato a grasp of the substance of Greek ethical life, but pointed out, in the remark to § 185, that Plato’s city leaves no room for the modern principle of subjective freedom. In the Christian tradition, Augustine drew on Platonic themes, but the City of God proposes a different political order and notion of justice. See Saint Augustine.

Karl Popper and The Open Society

The most influential critique of the twentieth century is that of Karl Popper (1902–1994) in The Open Society and Its Enemies (London, 1945), whose first volume is titled The Spell of Plato. Popper claims that Plato’s political philosophy has totalitarian tendencies: it espouses a historicism (the idea that history degenerates and that the state must be fixed in order to halt the decay), a holism in which the individual is subordinated to the city, the political use of lies, and a rigid division into classes. According to Popper, Platonic “justice” amounts to class inequality rather than equality before the law, and Plato betrayed the legacy of Socrates, whom Popper associates with individualism and the open society. See also Popper and Philosophy of science: Popper and Kuhn.

The book provoked intense debate. Ronald B. Levinson, in In Defense of Plato (1953), contested Popper’s reading systematically, and Popper himself answered his critics in later editions of the work. Other scholars have generally held that Popper reads Plato too literally when it suits him and that political anachronisms (such as “totalitarianism”) make it harder to understand a fourth-century BCE author. Authors such as Leo Strauss (The City and Man, 1964) propose that the city of the Republic is not a political program to be implemented but an instrument for revealing the limits of politics and the nature of the soul. The text itself suggests as much when it speaks of a model “in heaven” (592b) and when Socrates describes the construction as “in words” (369a, 472d–473b).

Other lines of criticism

Among the internal problems discussed in the specialist literature are the city–soul analogy (questioned, among others, by David Sachs in “A Fallacy in Plato’s Republic”, 1963, and by Bernard Williams in “The Analogy of City and Soul in Plato’s Republic”, 1973), the question of whether the just life is preferable in itself or only for its consequences, and the position of women. On the latter, Julia Annas and Susan Moller Okin assessed, from different perspectives, how far the proposal of Book V can be read as feminist; Okin, in Women in Western Political Thought (1979), argued that the equality proposed is restricted to the guardian class and subordinated to the city’s ends. Julia Annas, in An Introduction to Plato’s Republic (1981), offers one of the most widely used analytical introductions to the work.

Why read the Republic today

The Republic retains its relevance less as a program than as a set of questions that still structure philosophy: is justice a convention or a natural order? Is there a connection between knowledge and political legitimacy? How does education form character? What is the relation between the order of the soul and the order of the city? Glaucon’s challenge, in particular, reappears whenever one asks whether morality can be separated from self-interest, and the typology of regimes continues to be read in terms of political philosophy and moral psychology. For students the usual rule applies: cite with the Stephanus number, distinguish what Socrates says from what Plato holds, and remember that this is a dialogue, not a treatise.

References

• PLATO. Republic. Trans. G. M. A. Grube, rev. C. D. C. Reeve. Indianapolis: Hackett, 1992.
• PLATO. Platonis Respublica. Ed. J. Burnet. Oxford Classical Texts, 1902.
• ARISTOTLE. Politics, Book II, chs. 1–5.
• ARISTOTLE. Nicomachean Ethics, I.6.
• ANNAS, Julia. An Introduction to Plato’s Republic. Oxford: Clarendon Press, 1981.
• FERRARI, G. R. F. (ed.). The Cambridge Companion to Plato’s Republic. Cambridge University Press, 2007.
• LEVINSON, Ronald B. In Defense of Plato. Cambridge, MA: Harvard University Press, 1953.
• OKIN, Susan Moller. Women in Western Political Thought. Princeton University Press, 1979.
• POPPER, Karl. The Open Society and Its Enemies. 2 vols. London: Routledge, 1945.
• SACHS, David. “A Fallacy in Plato’s Republic”. The Philosophical Review 72 (1963).
• STRAUSS, Leo. The City and Man. Chicago: University of Chicago Press, 1964.
• WILLIAMS, Bernard. “The Analogy of City and Soul in Plato’s Republic”. In: LEE, E. N. et al. (eds.), Exegesis and Argument. Assen: Van Gorcum, 1973.

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