The Complete Works of Plato
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Early period
Apology
Socrates' defense speech at his trial in 399 BCE, charged with impiety and corrupting the youth. One of the most vivid portraits of Socrates, revealing his mission, his irony, and his willingness to die for philosophy.
InterlocutorsSocratesMeletus
17a–20c
Opening — dismissal of past slanders
Socrates opens by distinguishing two waves of accusers. The 'old' accusers — decades of popular prejudice fed by Aristophanes' Clouds, which depicted him as a sophistic natural philosopher — are more dangerous because anonymous and ingrained since the jurors' childhoods. The 'new' accusers (Meletus, Anytus, Lycon) bring the formal charges. Socrates apologizes for speaking plainly rather than in courtroom rhetoric — at 70, he says, this is his first time in court, and he will speak as he does in the marketplace.
20c–24b
The Delphic Oracle and the Socratic mission
Socrates explains the origin of his philosophical mission. His friend Chaerephon asked the Delphic Oracle whether anyone was wiser than Socrates; the priestess answered no. Puzzled — he was conscious of knowing nothing significant — Socrates set out to refute the god by finding someone wiser. He examined politicians, poets, and craftsmen. Each turned out to think they knew important things they did not. Socrates's only superiority: he knew that he did not know. The mission to test others is therefore divine service, not personal vanity — and it has earned him his enemies.
24b–28a
Reply to Meletus — the formal charges
Socrates cross-examines his accuser Meletus and exposes incoherence. Meletus claims Socrates corrupts the youth alone, while every other Athenian improves them — absurd, since with horses only experts improve them. Asked whether Socrates corrupts intentionally or unintentionally, Meletus says intentionally — but no one harms their own associates intentionally, since one is then harmed by them. On impiety: Meletus accuses Socrates of complete atheism while the indictment also charges introducing new divinities. The contradiction destroys the formal case.
28a–35d
The philosopher's indifference to death
Socrates addresses the worry that his philosophical life has put him at mortal risk. A good man should consider only one question — whether what he does is just or unjust — never whether it endangers him. He invokes Achilles, who chose death over dishonor. Even if Athens offered acquittal in exchange for ceasing philosophy, he would refuse: he must obey the god rather than men. Death is either a dreamless sleep (no evil) or a journey to be with Homer, Hesiod, and Odysseus, where he can continue his examinations forever (a great good).
35e–38b
Penalty phase — refusal to propose exile
Convicted by roughly 281 to 220 (Socrates says that if about thirty votes had shifted he would have been acquitted), Socrates faces the penalty phase: Athenian law requires the defendant to propose an alternative to execution. Exile would mean the same problem in another city; ceasing philosophy is impossible because it is divine command. Instead, what he truly deserves for his service to Athens is a public benefactor's privilege — free meals in the Prytaneum (the civic hearth of Athens), the honor reserved for Olympic victors. This calculated provocation guarantees the death sentence. He eventually proposes a token fine, increased to 30 minae (a substantial sum — roughly 10 years' wages for a laborer) when friends offer to pay.
38c–42a
Final address to the jury
After the death sentence, Socrates speaks twice. To those who voted for death: they have not escaped scrutiny — younger followers will continue his work, more bitterly. The real evil is not dying but acting unjustly, which they have done. To those who acquitted: take heart. His daimonic sign did not stop him at any point today, suggesting death is no evil. He concludes with one of philosophy's most famous lines — the unexamined life is not worth living for a human being — and departs: 'The hour of departure has arrived, and we go our ways — I to die, and you to live. Which is better God only knows.'
Euthyphro
Outside the court before his trial, Socrates meets Euthyphro, who is prosecuting his own father for manslaughter. Socrates uses the encounter to examine what piety truly is — a masterclass in dialectical refutation.
InterlocutorsSocratesEuthyphro
2a–5c
The meeting and context
Socrates is at the King Archon's court answering Meletus's indictment for impiety. Euthyphro, a self-styled religious expert, is prosecuting his own father for the death of a hired laborer who had killed a slave — a shocking act in Greek family ethics. Euthyphro's confidence that he knows what piety demands sets up the irony: the man Socrates is about to interrogate claims expertise in the very subject for which Socrates is being tried.
5c–6e
First definition — piety is what I am doing now
Euthyphro answers that piety is what he is doing now — prosecuting wrongdoers — citing Zeus, who punished his own father Cronos. Socrates rejects this as an example rather than a definition. He demands the one Form (eidos) by which all pious actions are pious — the standard or pattern (paradeigma) by which we can judge any case. This is the first clear formulation in Plato of the demand for definition by Form.
7a–8b
Second definition — piety is what is dear to the gods
Euthyphro proposes that piety is what is dear to the gods. Socrates points out that Greek myth is full of divine quarrels — gods disagree about what is just, beautiful, and good. The same action would be loved by some gods and hated by others, making it simultaneously pious and impious. The definition makes piety self-contradictory.
9d–11b
Third definition — piety is what all gods love
Euthyphro repairs the definition: piety is what all the gods love. Socrates poses the famous Euthyphro Dilemma: is the pious loved by the gods because it is pious, or is it pious because they love it? Euthyphro chooses the first horn — the gods recognize independent goodness — but this means divine love is only a consequence of piety, not its definition. Piety must have an independent nature the gods are tracking. The dilemma still drives debates in moral theology about divine command theory.
11e–14b
Fourth definition — piety as service to the gods
Euthyphro tries: piety is the part of justice concerned with caring for the gods. Socrates probes — what does this 'care' produce? Humans tending horses make horses better, but surely we don't make the gods better. Euthyphro retreats to piety as 'service' or a kind of exchange: gods give us goods, we give them honor. But what gifts could the gods need from us? Only what pleases them — collapsing back into what the gods love. The definition has gone in a circle.
15c–16a
Aporia — the dialogue ends unresolved
As Socrates pushes for another attempt, Euthyphro suddenly remembers urgent business and flees. No definition has survived examination. The dialogue ends in aporia — productive perplexity — but its real lesson is dramatic: Euthyphro is about to commit a religiously charged act (prosecuting his father) without being able to define what religion requires. This is the Socratic indictment of conventional piety.
Crito
In prison awaiting execution, Socrates debates with Crito whether he should escape. Through the voice of the Laws of Athens, Socrates argues it would be unjust to break the agreement he has with the city.
InterlocutorsSocratesCrito
43a–44b
Crito's plea and the dream
Crito has bribed the jailer and arrived before dawn with an escape plan: friends abroad will receive Socrates, costs are covered, refusing to escape would shame his friends and abandon his children. Socrates remains calm — he relates a dream in which a beautiful woman in white quoted Homer, telling him he would arrive in 'fertile Phthia' in three days. In the Iliad (9.363), Phthia is Achilles' homeland — 'going to Phthia' means going home. Socrates reads the dream as a prophecy: death, his true homecoming, will arrive on the third day. The question therefore deserves careful argument, not panic.
44b–46b
The standard of the expert opinion
Socrates establishes the methodological principle. We should not be moved by 'what the many think' — most people's opinions are no better than chance. Just as we trust the doctor about our body, on questions of justice we should follow only the expert: the one who knows. The body, harmed by bad medicine, is less precious than the soul, harmed by unjust action. So the question is not what the many will say, but what is genuinely just.
46c–49e
The argument from agreement
Socrates establishes two general principles he and Crito both accept: one must never do injustice, even when wronged; and one must never break a just agreement. He then applies these. By living in Athens for 70 years without leaving, raising his family there, and benefiting from its laws, Socrates has tacitly contracted to obey. To escape now would break this agreement and harm the city by undermining its legal authority — returning evil for the good he has received.
50a–54c
The voice of the Laws
Socrates dramatizes the argument by imagining the Laws of Athens themselves confronting him. They speak as parents and benefactors: through the laws, Socrates' parents married, he was educated, he received civic protection his whole life. The relationship is even more sacred than that to natural parents — and one may not strike one's parents even when struck. To break the law because it has wronged you is to repay good with evil. If a citizen disagrees with a law, he must persuade the city or accept its judgment. Escape would prove all his lifetime talk of justice was empty.
54d–54e
Conclusion — obedience
Socrates says the Laws' words ring in his ears like the music of the Corybantes (ecstatic ritual dancers of the cult of Cybele) — drowning out all other arguments. He hears it as a divine summons. Escaping would not benefit himself, his friends, or his children, but would damage his soul. He turns to Crito: do you have anything more to say? Crito has nothing. Then, says Socrates, let us go this way, since this is the way the god leads.
Charmides
Socrates returns from military campaign and meets the beautiful Charmides. Multiple definitions of temperance are examined: quietness, modesty, doing one's own business, and self-knowledge — all found wanting.
InterlocutorsSocratesCharmidesCritias
153a–159a
Prologue — return from Potidaea
Socrates has just returned from the bloody battle of Potidaea (432 BCE) and visits the wrestling school of Taureas. Chaerephon presses him for war news; Critias presents his beautiful young cousin Charmides, said to combine physical beauty with a soul to match. The frame is laden with dramatic irony: both Charmides and Critias would later become two of the Thirty Tyrants who terrorized Athens — failures of the very temperance under discussion.
159b–160d
First definition — temperance is quietness
Charmides defines temperance (sophrosyne — moderation, self-control) as a kind of orderly quietness — moving and speaking calmly. Socrates refutes by counter-example: in reading, writing, music, gymnastics, and most arts, quickness is better than slowness, and the quick are praised more than the slow. If quietness were temperance, fast and skillful action could not be called temperate, which is absurd.
160e–161b
Second definition — temperance is modesty
Charmides redefines temperance as modesty (aidos — shame, reverent restraint). Socrates cites Homer: 'modesty is no good companion for a needy man.' A poor man should not be too modest to ask for help. So modesty is sometimes good and sometimes not — but a virtue must be good without qualification. Temperance therefore cannot just be modesty.
161b–162b
Third definition — doing one's own business
Critias intervenes with a saying he says he heard from someone wise: temperance is 'doing one's own things' (ta heautou prattein) — minding one's own business. Socrates probes: in cities, craftsmen make things for others — would we say the city is intemperate? Critias must distinguish 'doing' (poiein) from 'making' (prattein) and 'one's own' as morally one's own (good actions). The definition becomes too elastic to test.
163e–175a
Fourth definition — self-knowledge
Critias proposes the Delphic 'know thyself': temperance is self-knowledge — a knowledge that knows itself and the other knowledges. Socrates raises a deep puzzle: is there such a thing as a 'knowledge of knowledge' — a second-order discipline that knows itself and the absence of itself, but with no first-order content? Even granting it exists, what good would it do? It would tell us we know or do not know, but not what we know. Mere self-knowledge without knowledge of the good cannot make us happy. Genuine temperance must be tied to knowledge of good and bad.
175a–176d
Aporia and warning
The dialogue ends in apparent failure — temperance has not been defined. But Socrates expresses concern not for the argument but for Charmides: the boy clearly has temperance in some real sense, even if no one can give a definition. He warns him to associate with Socrates for the 'charm' (epodē) that produces real temperance. The dramatic irony hangs heavy: Charmides will not heed this warning, and his political career will end in tyrannical violence.
Laches
Two Athenian generals, Laches and Nicias, debate the nature of courage with Socrates, spurred by a discussion about whether sons should learn to fight in armor.
InterlocutorsSocratesLachesNiciasLysimachusMelesias
178a–181d
Opening — should boys learn to fight in armor?
Two distinguished but undistinguished sons (of the great Aristides and Thucydides) — Lysimachus and Melesias — want better for their own sons. They have invited the generals Laches and Nicias to watch a demonstration of armored fighting (hoplomachia) and advise whether to enroll their boys. The generals split: Nicias supports the new training, Laches dismisses it as useless. They invite Socrates, recently distinguished for valor at Delium, to break the tie. He redirects: the question is not about armor but about courage, and beyond courage, virtue itself.
190e–192b
Laches' first definition — standing firm in battle
Laches the soldier's-soldier offers the fighting man's definition: courage is standing your ground in the battle line and fighting the enemy, never retreating. Socrates objects: the Spartans at Plataea retreated as a tactic, then turned and won. Sea warfare and cavalry fighting both require movement, not standing firm. And courage exists in many other domains — facing illness, poverty, political dangers, and one's own desires and fears. The definition captures only one form of one kind of courage.
192b–194b
Laches' second definition — endurance with wisdom
Laches reformulates: courage is endurance (karteria) of soul. Socrates suggests it must be wise endurance — but here a paradox surfaces. Imagine two soldiers facing the enemy: one who has expert knowledge of his strength and the terrain, and one who plunges in ignorant. We tend to think the foolish one shows more courage, not less, in his willingness to endure without security. So either foolish endurance is courage (but how can a virtue be foolish?), or courage requires more than endurance plus belief.
194c–199e
Nicias' definition — knowledge of the fearful and hopeful
Nicias offers a more Socratic answer borrowed from Socrates himself: courage is the knowledge of what is to be feared and what is to be hoped for — what is genuinely fearful (real evils) versus apparent dangers. Laches objects: this would deny courage to animals (lions, bulls) and children, who clearly act bravely. Nicias accepts the consequence: animals are merely fearless, not courageous, because they lack knowledge. True courage is a rational virtue.
199e–201c
Refutation of Nicias and aporia
Socrates pushes Nicias's definition further. Knowledge of what is fearful and hopeful is knowledge of future goods and evils. But knowledge of future goods and evils cannot be separated from knowledge of present and past goods and evils — and this is knowledge of all goods and evils, which would be the whole of virtue, not just one part. Nicias's definition would make courage identical with virtue, contradicting the assumption that courage is a part. The puzzle (the unity of virtue) emerges but is left unresolved. The generals laugh that they cannot define their own profession; Socrates suggests they all need a teacher.
Lysis
Socrates draws the beautiful Lysis and his friend Menexenus into a discussion of what makes people friends. Several competing theories are examined — all of which fail.
InterlocutorsSocratesLysisMenexenusHippothalesCtesippus
203a–207d
Setting — the wrestling school
On his way to the Lyceum, Socrates is intercepted by Hippothales, hopelessly in love with the boy Lysis. Hippothales has been embarrassing himself by composing flowery poems praising Lysis's lineage. Socrates offers to demonstrate how to woo properly — by humbling rather than puffing up the beloved, since the lover should make the beloved better. He enters the wrestling school where Lysis and his friend Menexenus are.
207d–210d
First theory — we are loved for our usefulness
Socrates draws Lysis into conversation about his parents. They love him — yet they restrict him from countless activities. Why? Because they only entrust him with what he has the knowledge to manage well. They will love him to the extent he is useful, and to the same extent the city, foreigners, even the Persian king will value him. Socrates extracts a deflating truth: love and worth track usefulness and knowledge, not unconditional affection. The boy learns humility.
212a–213d
Can like be friends with like?
Socrates and Menexenus test the poetic saying that 'like is friend to like' (Homer, Hesiod, Empedocles all attested it). The argument fails on two grounds: (1) bad men cannot be friends with bad men, since the bad are unstable and harmful; (2) good men, being self-sufficient, need nothing — so they have no basis for needing each other. Like attracts like only superficially; deeper analysis dissolves the principle.
215e–216b
Can opposites be friends?
Try the opposite: perhaps unlike seeks unlike — the dry desires the wet, the empty desires the full. But this view, taken strictly, would make the just friend to the unjust, the temperate friend to the licentious, the good friend to the bad — clearly absurd. Neither like-likes-like nor opposites-attract works as a definition of friendship.
216c–221b
The first beloved — the Good and the neither-good-nor-bad
Socrates introduces a new candidate. Friendship arises in the middle category: the not-yet-good but not-yet-incurably-bad. The sick body loves the doctor (the good) because illness (evil) is present in it. Without illness it would not love medicine; without health to attain, it could not love. So friendship is the love directed by what is intermediate toward the good, because of the presence of evil — desire generated by lack.
221b–223b
Aporia — the regress of friendship
But this creates a regress. We love the doctor for the sake of health; health for the sake of avoiding pain; and so on. There must be some 'first beloved' (proton philon) for whose sake everything else is loved — perhaps the Good itself. Yet if evil were eliminated, would friendship vanish too? Some desires (hunger, thirst) seem neutral, suggesting we love the Good even apart from evil. The dialogue ends in aporia: Socrates declares that he, Lysis, and Menexenus have all become friends, yet they cannot say what a friend is — a beautiful philosophical irony.
Protagoras
Socrates and Hippocrates visit the famous sophist Protagoras. Their extended debate covers whether virtue is one or many, whether it can be taught, and whether courage is ultimately a form of knowledge.
InterlocutorsSocratesProtagorasHippocratesHippiasProdicusCalliasAlcibiades
309a–317e
Introduction — the house of Callias
Hippocrates bursts into Socrates's house before dawn, ecstatic that Protagoras of Abdera has arrived in Athens — he wants to study with him. Socrates warns: a sophist sells food for the soul, but unlike with body-food (where you can examine ingredients before eating), soul-food is consumed in the very act of receiving it. You must know what is good for the soul before exposing it. They go to the lavish house of Callias, where the great sophists Protagoras, Hippias, and Prodicus all hold court like rival philosophers.
320c–328d
Protagoras' Great Speech — the myth of Prometheus
Asked whether virtue can be taught, Protagoras delivers his Great Speech, choosing myth then argument. The myth: Prometheus gave humans the technical arts (fire, crafts) but humans were doomed because they could not live together. Zeus sent Hermes to distribute civic virtue (aidos and dike — shame and justice) — but to all humans equally, not to specialists, since otherwise cities could not exist. This explains why everyone has standing to speak on justice in the assembly, while only experts speak on shipbuilding. Argument: virtue is teachable, since we punish wrongdoers (which presupposes correctibility), educate children in it, and society as a whole teaches it. The sophist merely teaches it more expertly.
329b–334c
Are the parts of virtue separate or one?
Socrates raises the Unity of Virtue question. Are wisdom, courage, temperance, justice, and piety distinct parts of virtue (like parts of a face — eyes, ears, nose) or distinct names for the same thing (like parts of gold, all gold)? Protagoras opts for the face model: parts that work together but are different, with different functions. Socrates begins to dismantle this. Take justice and piety: pious things are just, and just things are pious. Take wisdom and temperance: both involve thinking rightly. Each pair seems to collapse on inspection. Protagoras grows defensive.
338e–348a
Interlude — the poem of Simonides
To break the deadlock, Protagoras shifts to interpreting a poem of Simonides about virtue ('It is hard to become truly good...'). What follows is a parody of sophistic literary interpretation. Socrates, dazzlingly and tongue-in-cheek, extracts a Socratic doctrine from the poem — that no one does wrong willingly, that being and becoming good are different — finding philosophical depths the poet probably never intended. The episode satirizes the sophistic habit of using poetry as authority while showing Socrates can play this game better than any sophist.
351b–358d
Are pleasure and good the same? — hedonism
Returning to argument, Socrates and Protagoras together examine the popular view that one can know what is right and yet be 'overcome by pleasure' (akrasia, weakness of will). They argue together against the many: if pleasure is the good, then 'being overcome by pleasure' just means choosing a worse outcome (less pleasure) over a better outcome (more pleasure) — which would be a sheer mistake of measurement. Akrasia, properly understood, isn't moral weakness but a calculation error. No one knowingly chooses what is worse. This is the Socratic intellectualist thesis: all wrongdoing is ignorance.
356c–360e
The science of measurement
Socrates draws the metaethical conclusion: if pleasure is the good, then ethics requires a metretic (measuring) art — a science of correctly measuring pleasures and pains across time, weighing nearer pleasures against farther but greater ones, and so on. This is a kind of knowledge. So virtue is knowledge. The argument is partly hypothetical (if hedonism, then virtue-is-knowledge); Socrates may not personally hold the hedonist premise. But the conclusion fits his consistent position throughout the early dialogues.
360e–362a
Reversal — conclusion
The dialogue ends in a comic reversal. Protagoras, who began arguing virtue is teachable, now finds himself denying that courage is identical with knowledge (and so resisting the unity-of-virtue conclusion). Socrates, who began by professing not to know whether virtue is teachable, has been led by argument to the position that if virtue is knowledge, it must be teachable. They have swapped sides. Both note the strangeness: the discussion needs another round, but they part on good terms.
Ion
A brief dialogue with the rhapsode Ion, who claims special expertise on Homer. Socrates argues poetic success comes not from skill but from divine inspiration.
InterlocutorsSocratesIon
530a–531d
Ion's claim to expertise
Ion of Ephesus, a celebrated rhapsode (a professional reciter and interpreter of poetry), has just won first prize at the festival of Asclepius in Epidaurus and is about to compete at the Panathenaea in Athens. He boasts that he can speak more brilliantly about Homer than anyone else. Socrates poses what looks like an innocent test question: if Ion has expert knowledge of Homer, can he also speak expertly about Hesiod and the other poets, since poetry is presumably one art? Ion admits he is brilliant only on Homer; on others he 'dozes off.' This is the seam Socrates will work.
532c–536d
The magnet analogy — divine inspiration
If Ion truly had a techne (an art, a skill with rational principles), it would apply across all instances — a master of arithmetic understands all numbers, not just Homeric numbers. But Ion can only perform Homer well. So his ability cannot be techne. Instead, Socrates proposes the magnet analogy: the Muse first inspires the poet, who in his madness composes; the poet then inspires the rhapsode like a magnetized iron ring inspiring a second ring, which inspires the audience. Each link is moved not by knowledge but by divine attraction. Ion is a ring in the chain. The whole apparatus of poetic transmission is divine possession, not skill.
536d–541b
Poets and generals
Ion protests: surely Homer's military passages mean Ion has knowledge of generalship; surely Homer's medical passages mean he has medical knowledge. Socrates patiently shows that whatever subject Homer treats — chariot-driving, fishing, prophecy, generalship — actual experts (charioteers, fishermen, prophets, generals) would judge Homer's accuracy better than the rhapsode. The rhapsode has no specific subject-matter expertise. Pressed harder, Ion finally retreats to claiming knowledge specifically of generalship. Socrates suggests he sail off to lead Athenian armies — and Ion declines.
541b–542b
Conclusion — divine madness, not knowledge
Socrates poses a final dilemma. Either Ion has techne (skill grounded in knowledge) — in which case, why can he speak only of Homer? he is a fraud and ought to be ashamed — or his ability is divine inspiration. Ion chooses to be called divinely inspired. The dialogue thus achieves a startling result: the highly-paid celebrity rhapsode has been disenfranchised both as expert (by his own admission) and as artist (since divine inspiration is a passive receptacle, not a skill). The implications for poetry are large; they will be developed in the Phaedrus (where divine madness becomes a positive principle) and in the Republic (where inspiration without knowledge is grounds for banning poetry from the ideal city).
Gorgias
Socrates debates the great rhetorician Gorgias, then his student Polus, then the ambitious Callicles. The dialogue builds to a stark confrontation: is it better to suffer injustice or commit it?
InterlocutorsSocratesGorgiasPolusCalliclesChaerephon
447a–461b
What is rhetoric? — Gorgias' definition
Socrates arrives just as Gorgias has finished a public display. He immediately presses for a definition. Gorgias, the master rhetorician, claims rhetoric is concerned with 'the greatest of human concerns,' producing persuasion in any audience on any subject — even outdoing the doctor at convincing a patient to take medicine. Socrates introduces a fundamental distinction. Genuine arts (medicine, gymnastics, legislation, justice) aim at the real good of the body or soul. Rhetoric, like cosmetics or pastry-making, is a knack (empeiria) — it produces only the appearance of good without the knowledge. Rhetoric stands to justice as cooking does to medicine: a counterfeit that pleases without healing.
461b–481b
Rhetoric vs. justice — Polus challenges Socrates
Gorgias's student Polus takes over, scandalized by the demotion of rhetoric. He cites Archelaus of Macedon, who murdered his way to the throne and now lives in luxury — surely happy! Socrates inverts the popular view with two paradoxes: orators and tyrants have great power to do as they wish, but no power to do what they really want (the good); and Archelaus is the most wretched of men because he has corrupted his soul with injustice. Socrates is unmoved by Polus's appeals to popular opinion — he wants only Polus's own assent, gained by argument.
474b–481b
The paradoxes of Socratic ethics
Socrates defends two famously counterintuitive theses. (1) It is worse to do injustice than to suffer it — because injustice harms the doer's soul, and the soul is more important than the body or external goods. (2) It is worse for the unjust to escape punishment than to be punished — because unpunished injustice festers and grows worse, while punishment is the soul's medicine, restoring its order. So a man who has done wrong should rush to a court for treatment, just as the diseased rush to the doctor. The argument inverts every popular intuition about happiness.
481b–505b
Callicles — the tyrant's argument
Callicles, an ambitious young Athenian gentleman destined for political life, takes over from the embarrassed Polus. He attacks Socrates' position as the philosophy of weaklings. He distinguishes nature (physis) and convention (nomos): conventional justice is a contract by which the weak many constrain the strong few, who naturally deserve more. The truly natural law is that the strong should rule and have more — and the truly free man should let his desires grow as large as possible and have the courage to satisfy them. Philosophy is fine for boys but a disgrace in grown men. Socrates faces the deepest challenge of his ethical position.
491d–497a
Pleasure and the good — the leaky jar
Callicles identifies the good with pleasure and the happy life with the unrestrained satisfaction of ever-growing appetites. Socrates uses two memorable images. (1) The soul of the intemperate man is like a leaky jar that must be perpetually refilled — never full, never satisfied. The temperate soul, with smaller intact jars, enjoys real fullness. (2) An orderly soul shares in the cosmic order (kosmos): the good life requires limit, proportion, and structure. Pleasure and good are not the same — we sometimes feel pleasure in bad things (when scratching an itch) and pain in good things (when undergoing surgery). Pleasure is therefore not the standard.
515a–523a
The life of the philosopher vs. the politician
Socrates draws the political conclusion. The true statesman aims to make citizens virtuous, just as the doctor aims to make bodies healthy. By this standard, the celebrated Athenians — Themistocles, Cimon, Pericles — were all failures: they pampered the city with harbors, walls, and tribute, but did not improve its citizens, who in the end turned on each of them. Socrates claims, half-seriously, to be the only Athenian practicing the true political art: making citizens better through philosophical examination. The orator-politician's life is wretched flattery; the philosopher's life, even if it ends at the executioner's block, is truly happy.
523a–527e
The myth of judgment — final eschatology
Socrates closes with a great myth. In Cronus's day, the living judged the living at sundown — and the unjust deceived the judges with their reputations. Zeus reformed the system: souls are judged after death, naked and stripped of bodies and circumstances, by judges (Minos, Rhadamanthys, Aeacus) who are themselves dead and can see only the soul's true condition. The unjust soul, scarred by its acts, is sent to Tartarus for purification (or, if incurable, eternal punishment as a deterrent). The just philosopher's soul, beautiful and orderly, goes to the Isles of the Blest. The myth gives narrative form to the dialogue's argument: justice is the soul's true health, and reality always catches up with appearance.
Euthydemus
Socrates witnesses two brothers, Euthydemus and Dionysodorus, demonstrate their 'eristic' (combative argument aimed at verbal victory rather than truth) art on the young Clinias. The dialogue alternates between comic displays of sophistic fallacies and serious Socratic arguments about the nature of wisdom.
InterlocutorsSocratesEuthydemusDionysodorusCliniasCritoCtesippus
271a–275c
Prologue — the brothers' claim
Two aging brothers, Euthydemus and Dionysodorus — formerly teachers of pankration (an all-in combat sport combining wrestling and boxing) and forensic rhetoric — now claim to have mastered the new art of eristic disputation, and to teach virtue faster and better than anyone. Socrates wryly defers to them as if they were authorities, while Crito (the framing listener) is meant to judge whether such teachers are worth Crito's son's time. The dialogue alternates eristic display with serious Socratic argument.
275d–278e
First eristic display — you know everything or nothing
The brothers attack the young Clinias with a paradox of learning: those who learn are either the wise (who already know) or the ignorant (who cannot recognize what they're learning). Either way, no one actually learns. They deploy fallacies of equivocation — sliding between 'know' (have grasped) and 'know' (be in the act of knowing). Socrates rescues Clinias by interrupting with a serious protreptic (exhortation toward philosophy): real philosophy proceeds by genuine questions, not verbal tricks.
278e–282e
Socrates' first interlude — wisdom and happiness
Socrates delivers his first interlude — a sustained protreptic to philosophy. Conventional 'goods' (wealth, health, beauty, noble birth, even virtues like courage) are good only when used wisely; misused, they amplify harm. The greater the resource, the worse the disaster if foolishly deployed. Therefore only wisdom is unconditionally good, and only ignorance unconditionally bad. Happiness depends entirely on cultivating wisdom — anticipating the Stoic doctrine that virtue alone is genuinely good.
283a–288b
Second eristic display — paradoxes of predication
The brothers return with paradoxes that exploit the puzzle of not-being. (1) Speaking falsely is impossible: you cannot say what is not, so anything said must be true. (2) Contradicting is impossible: if two people say different things, they must be talking about different things, so they cannot really disagree. These were genuine puzzles in early Greek logic, traceable to Parmenides — and Plato will solve them seriously in the Sophist by analyzing not-being as 'difference.' Here they are played for comedy.
288d–292e
Socrates' second interlude — philosopher vs. politician
In his second serious interlude, Socrates examines what wisdom is the wisdom OF. Each art produces something but does not know how to use it well; so we need a higher art to direct it. We move up: the political art, the kingly art. But what good does the kingly art produce? Wise citizens. Wise about what? The argument loops: every art needs a directing art, but the highest 'art of the good' has no clear product distinct from the goodness it imparts. The professional politician who despises philosophy is exposed as neither a real craftsman (he produces nothing definite) nor a philosopher (he claims to need no learning).
293a–307c
Third eristic display and Crito's warning
The brothers cap their performance with absurdities: since you have a dog and the dog is a father, the dog is your father. Socrates plays along with mock astonishment. Crito then reports a worried encounter with an unnamed sober citizen (often read as Isocrates) who warned him to keep his sons away from philosophers — they're useless verbal jugglers. Socrates closes by distinguishing genuine philosophy, which seeks the good, from eristic, which seeks only victory. Real philosophers are rare and worth seeking out, despite the bad imitators.
Meno
Can virtue be taught? The dialogue ranges over the nature of virtue, the paradox of inquiry, the theory of recollection (anamnesis), and whether virtue comes by divine gift. Features the famous geometry demonstration with a slave boy.
InterlocutorsSocratesMenoAnytusSlave boy
70a–79e
What is virtue? — catalogue of virtues
Meno, a young Thessalian aristocrat just arrived in Athens, opens with the question: can virtue be taught, acquired by practice, or does it come by nature? Socrates flips it: he doesn't even know what virtue is, much less whether it can be taught. Meno offers what he learned from Gorgias — a catalogue of virtues for different roles (man, woman, child, slave). Socrates demands the single Form (eidos) common to all of them, just as 'bee' has one essence beyond particular bees. Meno, untrained in such abstraction, struggles.
73c–79e
Several attempted definitions — all refuted
Meno tries: virtue is the desire for fine things and the power to attain them. But Socrates extracts the Socratic doctrine: nobody desires what they truly believe to be bad for them; everyone desires what they take to be good. So 'desiring the good' is universal — not what makes someone virtuous. The differentiating factor must be the 'power to attain' — but a power that produces good things justly. The definition has collapsed into 'getting good things justly,' which uses the very concept (justice) we're trying to define. We are going in a circle.
79e–80e
Meno's paradox — the impossibility of inquiry
Frustrated, Meno raises the eristic paradox: how will you inquire into something you don't know? If you don't know it, you won't recognize it when you find it; if you do know it, you don't need to inquire. Socrates calls this a lazy argument and offers a startling alternative: the soul is immortal and has known all things in previous lives. What we call 'learning' is really recollection (anamnesis) — drawing out latent knowledge through skilled questioning. Inquiry is possible because the answer is already buried in us.
80e–86c
The slave boy demonstration
To prove recollection, Socrates calls over Meno's slave boy — uneducated, no Greek geometry — and questions him about doubling the area of a square. The boy first guesses wrong (doubling the side), realizes his error under questioning (a productive aporia), and finally identifies the correct construction (the square on the diagonal). Crucially, Socrates only asks; he never asserts the answer. The boy is generating geometric knowledge from within. Therefore his soul must have known it before — in some prior state. Recollection is vindicated.
86d–89a
Virtue as a kind of knowledge — hypothetical method
Socrates introduces the 'method of hypothesis' borrowed from geometry. Hypothesize: virtue is some kind of knowledge. Then it would be teachable, since whatever is knowledge is teachable. Argument: virtue is admitted to be good; everything in the soul (courage, temperance, etc.) is beneficial only when guided by wisdom; therefore virtue, qua beneficial, is identical with wisdom. The conclusion: virtue is teachable IF it is knowledge.
89e–96d
Are there teachers of virtue? — Anytus
Anytus joins the conversation — a respectable Athenian who will later be one of Socrates's accusers. Socrates asks him: who teaches virtue? The sophists? Anytus erupts: the sophists corrupt their students. Then Athenian gentlemen? But Themistocles, Aristides, Pericles, Thucydides — all great men — failed to make their own sons virtuous, despite caring deeply and being able to afford the best teachers. If virtue could be taught, there would be teachers; but there are none. So virtue is not teachable. The chain breaks at the empirical premise.
96d–100b
Virtue as divine gift — true opinion
Socrates resolves the tension. If virtue is not teachable, it is not knowledge — yet virtuous statesmen do exist. They must be guided by true opinion (orthē doxa) rather than knowledge. True opinion guides correct action just as well as knowledge does — but it is unstable, like the statues of Daedalus that wander away unless tied down. Statues become firm when tied down by 'reasoning of the cause' (aitias logismos), which is what converts opinion into knowledge. So virtue in actual statesmen comes neither by teaching nor by nature, but as a divine gift through divine inspiration. The dialogue ends with the philosophical question reopened: real virtue, the kind that could be taught, would require a kind of knowledge no one has yet exhibited.
Middle period
Cratylus
A debate between Hermogenes (names are conventional) and Cratylus (names naturally fit their objects). Socrates mediates with an extended series of etymologies, concluding that names are unreliable guides to reality — only the Forms themselves are trustworthy.
InterlocutorsSocratesHermogenesCratylus
383a–385e
Hermogenes vs. Cratylus — convention or nature?
Hermogenes holds a conventionalist view: names are correct because we agree to use them — any name could have been any other, the connection is arbitrary. Cratylus, a Heraclitean, holds that each thing has a naturally correct name, fitted by nature to the thing itself; misuse of names is therefore impossible (you are either using a name properly or making meaningless noise). They invite Socrates to adjudicate.
388b–390e
Socrates sides with Cratylus — the craftsman of names
Socrates initially sides with Cratylus. Speaking and naming are actions, and like all actions they have a proper way of being done — using the tool fitted to the work. The shuttle is fitted to weaving, the awl to leather; names are fitted to teaching and distinguishing things. The name-giver (onomatourgos) is therefore a craftsman who fashions the right name for each thing, looking to the thing's nature. The dialectician, who knows the natures, judges the name-giver's work.
391b–421c
The etymological tour de force
Socrates launches into a virtuoso (and partly comic) tour of Greek etymology. He derives the names of gods, heroes, virtues, and philosophical terms — 'Hades' from 'eidenai' (knowing); 'soul' (psychē) from 'breath-cooling' (anapsychon); 'justice' (dikaiosynē) from 'going through' (dia-iousa); and many more. Most etymologies suggest Heraclitean flux — that names were given by people who saw all things in motion. Whether Plato endorses these etymologies or satirizes the practice is debated; the brilliance with which Socrates produces them, and his occasional tongue-in-cheek manner, suggests both.
427d–433b
Critique of names — they can mislead
Then Socrates pulls back. Even if the original name-giver intended to fit names to natures, he might have been mistaken about the natures — perhaps he was wrong to believe everything is in flux. Names get corrupted across generations, with letters dropped or added for euphony. We cannot recover original meanings reliably. Names are not self-validating: a beautiful etymology proves nothing if the namer was confused.
438d–440e
Conclusion — only Forms are reliable
Socrates' positive conclusion. We cannot learn about reality from names alone — we must investigate the things themselves. If everything is in radical Heraclitean flux, knowledge is impossible (nothing stays the same long enough to be known), so the Heracliteans cannot consistently maintain their position. The Forms — the Beautiful Itself, the Good Itself — must be stable to be objects of knowledge. Cratylus, devoted to Heraclitus, departs unconvinced. The dialogue vindicates a Form-realist epistemology over both linguistic conventionalism and naturalism.
Symposium
A dinner party at the house of Agathon. Each guest delivers a speech in praise of Eros. The climax is Socrates' speech conveying the teaching of Diotima — love as ascent from beautiful bodies to the Form of Beauty itself. Alcibiades then praises Socrates directly.
InterlocutorsSocratesPhaedrusPausaniasEryximachusAristophanesAgathonAlcibiadesApollodorusAristodemus
178a–180b
Phaedrus' speech — Eros as oldest god
Phaedrus opens by praising Eros as the oldest and most venerable of gods. Love is the supreme moral force: it makes lovers ashamed to act badly before their beloveds. An army composed of lovers and beloveds would be invincible, as each would rather die than be seen as a coward. Even Alcestis chose to die for her husband, and the gods rewarded her uniquely. Love is the great inspiration to virtue.
180c–185c
Pausanias' speech — common vs. heavenly Eros
Pausanias refines Phaedrus by distinguishing two Aphrodites and so two Loves. Common Aphrodite (Pandēmos) inspires shallow attachment to bodies, indifferent to character — equally for women and boys, with no care for virtue. Heavenly Aphrodite (Ouranios) inspires love for the soul of intelligent young men, aiming at their improvement in virtue and wisdom. The dialogue distinguishes praiseworthy from corrupting forms of pederastic love, defending educational eros while rejecting mere sexual exploitation.
185e–188e
Eryximachus' speech — cosmic Eros
The physician Eryximachus extends Eros from human relationships to the entire cosmos. Health is harmony between opposed elements (hot/cold, wet/dry); medicine is the art of producing healthy love between the body's contraries. Music harmonizes high and low pitches into love. Astronomy and meteorology study the seasonal loves of the elements. Even religion mediates loves between gods and humans. Eros is the universal principle of cosmic harmony — a Pythagoreanizing extension of the theme.
189c–193e
Aristophanes' speech — the myth of the original humans
Aristophanes the comic poet recovers from hiccups and delivers the most memorable speech. Originally humans were spherical, with four arms, four legs, two faces, and one set of organs — three sexes (male, female, androgynous). Powerful and arrogant, they tried to climb Olympus. Zeus split each in two as punishment, leaving each half perpetually seeking its lost other. From the original males come gay men; from the original females, lesbians; from the androgynes, heterosexuals. Love is the longing to be made whole — the most poignant ancient image of love as recognition rather than appetite.
194e–197e
Agathon's speech — Eros as young and beautiful
The host Agathon, the celebrated tragedian, delivers a virtuoso piece of Gorgianic rhetoric. Where others praised what Eros does, he praises what Eros is: youngest of gods (always avoiding old age), most beautiful (since love seeks beauty), most temperate, just, and courageous. The speech is gorgeous and empty. Socrates, through gentle questioning, extracts a fatal admission: love is of something, and one desires what one lacks; so Eros lacks beauty and goodness — it cannot itself be beautiful and good in the way Agathon described. The speech collapses.
201d–212b
Socrates / Diotima — the ladder of beauty
Socrates says he learned the truth about Eros from the priestess Diotima of Mantinea. Eros is not a god but a daimon — between mortal and immortal, ugly and beautiful, ignorant and wise — born of Resource (Poros) and Poverty (Penia). Since Eros is intermediate between wisdom and ignorance, he is essentially a philosopher: one who loves wisdom without yet possessing it (203e–204b). The philosopher is an erotic being, and philosophy itself is a form of love — the soul's desire for what it lacks. Love is the desire to possess the good forever, expressed through 'giving birth in beauty' — bodily (procreation) or spiritually (poems, laws, philosophy). The Ascent: a young person properly trained in love begins by loving one beautiful body; recognizes the same beauty in all bodies; ascends to love the beauty of souls; then of laws and institutions; then of knowledge; finally beholds Beauty Itself — eternal, uniform, divine, the Form of Beauty. This vision alone produces true virtue.
212c–222b
Alcibiades' speech — the praise of Socrates
The drunk Alcibiades crashes the party, garlands Socrates, and replaces the praise of Eros with a praise of Socrates. Socrates is like a Silenus statue: grotesque on the outside, opening to reveal divine images within. He compares him to the satyr Marsyas who enchanted with music — Socrates enchants with mere words, gripping his listener's soul. Then the famous confession: Alcibiades tried to seduce Socrates, sleeping under his cloak — and Socrates remained completely unmoved, treating him like a son. Alcibiades, brilliant, beautiful, ambitious, and ultimately destructive, here represents what philosophy could not save. He embodies the failure of Athens to receive the philosopher's gift.
Phaedo
On the day of his execution, Socrates argues for the immortality of the soul. Contains the Theory of Forms in systematic form and four arguments for the soul's immortality. One of Plato's most profound and moving dialogues.
InterlocutorsSocratesPhaedoCebesSimmiasCritoEchecrates
57a–69e
Opening — why a philosopher faces death calmly
Surrounded by friends in his cell on his last day, Socrates explains why he is calm. The philosopher's whole life has been preparation for the separation of soul from body — and that separation is exactly what death is. The body deceives the senses, distracts with appetites, foments wars, and pulls the soul down. The soul attains pure knowledge only when withdrawn from the body, contemplating Forms with intellect alone. So a true philosopher should welcome death as the consummation of philosophical life. Suicide is forbidden — the gods are our owners — but death when it comes is to be embraced.
69e–72e
First argument — opposites (the Cyclical argument)
First proof, the Cyclical Argument. Everything that has an opposite comes to be from that opposite (the larger from the smaller, the awake from the sleeping). Living and dead are opposites; so the dead come from the living, and the living must come from the dead. Otherwise generation would have proceeded only one way and all souls would by now be in Hades — yet life continues. Therefore the soul must persist after death and return again. (The argument is suggestive rather than rigorous; Plato does not rest the case on it alone.)
72e–74a
Second argument — Recollection
Second proof, Recollection. Two equal sticks remind us of equality, but we recognize they fall short of true equality — equality is something more perfect than any pair of sticks. Yet our concept of perfect equality cannot have come from the imperfect equals we encounter through senses. We must have known equality before birth, and sensation merely re-awakens this knowledge. The same holds for goodness, beauty, justice, and all the Forms. So the soul existed before birth, in a state where it grasped pure Forms — and survival before birth, combined with the cyclical argument, gives survival after death.
74a–77a
Theory of Forms — systematic statement
Plato states the Theory of Forms in its mature mid-dialogue form. There are Forms (eidē, ideai) — Equal Itself, Beautiful Itself, Good Itself — that are eternal, unchanging, perfectly real, accessible only to intellect, never to the senses. Sensible particulars 'participate in' or are 'imitations of' these Forms but always imperfectly and changeably. Knowledge has Forms as its proper objects; mere opinion has sensible things. The whole epistemology and metaphysics of middle Plato condenses here.
77e–80b
Third argument — the soul's affinity with Forms
Third proof, the Affinity Argument. The Forms are invisible, unchanging, divine, simple, and indissoluble; the body is visible, changing, mortal, composite. The soul resembles the Forms, the body resembles bodies. By this affinity, the soul is more akin to what is indissoluble — therefore probably indissoluble itself. The philosopher who has practiced separating soul from body during life will at death go pure to join the divine; the appetite-driven soul, weighted with bodily attachments, may haunt graveyards as a ghost or be reincarnated into a beast suited to its character (gluttons into pigs, the violent into wolves).
84c–88b
Two counter-arguments — the attunement and the cloak
The three proofs so far have failed to convince two of Socrates' sharpest listeners. Simmias raises the Attunement Objection: the soul might be a kind of harmony (harmonia) of the body's elements — as the tuning of a lyre arises from the physical arrangement of its strings. When the lyre is smashed, the tuning perishes; when the body dies, the soul may likewise vanish. This is the strongest materialist challenge in the dialogue. Cebes follows with the Cloak Objection: even if the soul outlasts one body, it might eventually wear out — like a weaver who wears out many cloaks in his lifetime but himself finally dies. The soul might survive many incarnations yet still be mortal, perishing at last with some final body. Both objections accept the soul's relative durability but deny its indestructibility.
91c–95a
Refutation of the attunement theory
Socrates refutes Simmias's attunement theory on several grounds: (1) Recollection has already shown the soul exists before birth, but a harmony cannot precede the instrument it is a harmony of — the lyre must exist before it is tuned. (2) A harmony admits of degrees (more or less in tune), but we do not say one soul is more soul than another. (3) A harmony is entirely determined by its components and cannot oppose them — but the soul regularly opposes the body's appetites (the temperate soul resists hunger, thirst, and desire). The soul leads the body; a harmony cannot lead its instrument. The attunement theory is decisively refuted.
95a–102a
The method of hypothesis and the 'second sailing'
Against Cebes's stronger objection (that the soul may outlast several bodies but eventually perish), Socrates introduces a new method: the method of hypothesis. He traces his own intellectual autobiography — how as a young man he was excited by natural philosophy (Anaxagoras's promise that Mind orders all things, which turned out to be merely a nominal use of Nous with no real explanatory work). Disappointed, he undertook the famous 'second sailing' (deuteros plous, 99c–100a): the decisive methodological turn in which Socrates gives up investigating reality directly through the senses and instead investigates it through logoi — arguments and accounts. This is the founding moment of Platonic method: rather than asking 'what physical stuff is X made of?', Socrates now asks 'what Form does X participate in?' A thing is beautiful by participating in the Beautiful; large by participating in Largeness. He then lays down the principle that a Form can never admit its opposite — preparing the ground for the final argument.
102b–107a
Fourth argument — the Form of Life
Fourth proof, the most rigorous. Some properties are essentially tied to others: fire essentially carries the heat-Form (and so cannot admit its opposite, cold); snow essentially carries cold (cannot admit hot). Whatever the soul occupies, it makes alive: the soul essentially carries the Form of Life. So the soul, like fire vis-à-vis cold, cannot admit its opposite, death. The soul is not just immortal (athanatos) but imperishable (anōlethros) — it does not even admit perishing. Cebes is satisfied; Simmias retains some lingering doubt about the foundations, which Socrates accepts as appropriate humility.
108c–114c
The myth of the earth — geography of the afterlife
Socrates offers a mythical geography. The earth we inhabit is one hollow among many; the true earth, far above, is more beautiful, with brilliant colors, immortal trees and animals, and pure air. Below are vast subterranean rivers — Oceanus, Acheron, Pyriphlegethon, Cocytus — feeding the underworld. After death, souls are judged. Those of moderate life go to Acheron's lake to be purified; the curable are punished and released; the incurable are cast into Tartarus (the deepest pit of the underworld) forever; the truly holy ascend to the pure earth, and the philosophers, purified, ascend higher still to dwell with the gods. The myth dramatizes the metaphysical distinctions.
116a–118a
The death of Socrates
As the sun sets, Socrates bathes (sparing the women the work of washing his corpse) and bids farewell to his wife and children, sending them away. The jailer, in tears, hands him the hemlock with a touching apology. Socrates drinks calmly, without the slightest tremor. He walks until his legs grow heavy, then lies down. As the cold rises from his feet to his groin, he uncovers his face and speaks his enigmatic last words: 'Crito, we owe a cock to Asclepius; make this offering to him and do not forget.' Asclepius is the god of healing; the meaning has been debated forever — perhaps philosophy has cured him of life's sickness. Phaedo declares him the best, wisest, and most just man he ever knew.
Republic
Plato's magnum opus in ten books. What is justice? Socrates constructs an ideal city (Kallipolis) as a model for the just soul, describes the philosopher-king, introduces the Theory of Forms and the allegory of the Cave, and ends with the myth of Er.
InterlocutorsSocratesGlauconAdeimantusThrasymachusPolemarchusCephalusClitophon
327a–354c
Book I — Thrasymachus and the challenge
Socrates and Glaucon visit the Piraeus and end up at the house of Cephalus, the elderly metic (resident non-citizen). The old man genially says justice is telling the truth and paying back what one owes. Counter-example: returning a borrowed weapon to a friend who has gone mad would be unjust. Cephalus's son Polemarchus rescues the definition: justice is helping friends and harming enemies. Refuted: we may mistake friends for enemies; harming anyone makes them worse, which the just person cannot intend. The sophist Thrasymachus erupts impatiently: justice is simply 'the advantage of the stronger' — what rulers legislate to benefit themselves. Socrates refutes him on his own terms (rulers can mistake their advantage; arts aim at their object's good, not the practitioner's), but Thrasymachus only retreats to a cynical position. Socrates admits he has not really answered the deeper challenge.
357a–368c
Book II — Glaucon and Adeimantus challenge
Plato's brothers Glaucon and Adeimantus restate Thrasymachus's challenge in its strongest form. Glaucon proposes the Ring of Gyges thought experiment: a shepherd finds a ring that confers invisibility and uses it to seduce the queen, kill the king, and seize the throne. Would anyone, given such impunity, remain just? They argue justice is conventionally valued only for its consequences (reputation, rewards) — never as good in itself. Imagine a perfectly unjust man with the reputation of justice; and a perfectly just man with the reputation of injustice (tortured, crucified). Which life is happier? Socrates must show that justice is intrinsically good for the soul of the one who has it, regardless of consequences.
369b–417b
Books II–III — the founding of the city in speech
Socrates proposes to find justice in the city first, then read it back into the soul. He builds a city in speech, growing it from minimal needs — food, shelter, clothing — through the division of labor (each person doing one job best suited to nature) into a 'feverish' luxury city requiring soldiers. From soldiers emerges a class of full-time guardians, selected for spirit and philosophical aptitude, then split into Auxiliaries (warrior-defenders) and Rulers (philosopher-Guardians). Their education must be strictly controlled: poetry that depicts gods as immoral, heroes as fearful of death, or virtue as unrewarded must be censored — children's souls are imprinted by what they hear and imitate. The social structure is cemented by the Noble Lie (or 'magnificent myth'): citizens are told that God fashioned them with different metals in their souls — gold (rulers), silver (auxiliaries), bronze and iron (producers) — so that each accepts their station as natural and divinely ordained.
427d–445e
Book IV — the four virtues and justice defined
Justice in the city is identified through the four cardinal virtues. Wisdom belongs to the small ruling class who possess knowledge of the good; Courage belongs to the Auxiliaries who preserve in danger the right beliefs about what is to be feared; Temperance is the agreement among all three classes about who should rule; Justice is each class doing its own work and not meddling in another's. Socrates then transposes this to the soul. The soul has three parts: Reason (which calculates), Spirit (which feels indignation, the seat of honor), and Appetite (which desires food, drink, sex, money). Justice in the soul is each part performing its proper function under the rule of Reason, with Spirit as Reason's ally against Appetite. Internal harmony is the soul's health — and this analogy is made explicit (444c–445b): justice is to the soul what health is to the body, injustice what disease is. This is the direct answer to Glaucon's Book II challenge: justice is intrinsically good because it constitutes the soul's natural, flourishing condition, just as health constitutes the body's.
449a–480a
Book V — women, communism, and the philosopher-king
Three radical 'waves' of paradox. (1) Women guardians: women have the same nature as men relevant to ruling, only weaker; they should receive the same education and serve as guardians. (2) Communal living: guardians hold women, children, and property in common — eliminating private family loyalties and wealth, which generate faction. Reproduction is regulated by eugenic mating festivals; children are raised collectively without knowing their biological parents. (3) Philosopher-rulers: cities will not cease from evils until philosophers become kings or kings genuine philosophers. The philosopher loves all wisdom, has knowledge of the Forms, and would prefer to contemplate truth — making him the only one fit to rule, because the only one who does not want to.
504e–511e
Book VI — the Form of the Good and the Sun analogy
Asked what the Form of the Good is, Socrates declines to define it directly — too far above his vision — and offers instead the Sun analogy. As the sun in the visible world makes things visible, generates them, and gives them life, so the Form of the Good in the intelligible world makes things knowable, gives them being, and is the source of all truth. The Good is what every soul pursues without knowing what it is. It is 'beyond being' (epekeina tēs ousias) in dignity and power — the highest Form, source of intelligibility and reality.
511c–521b
Books VI–VII — the Divided Line and the Cave
Two more analogies. The Divided Line: a line cut in proportional segments representing four cognitive states and their objects — Imagination/eikasia (shadows, reflections), Belief/pistis (sensible objects), Thought/dianoia (mathematical reasoning from hypotheses), Understanding/noēsis (dialectical grasp of the Forms and the Good). Then the Cave: prisoners chained from birth see only shadows on a wall, cast by puppets passing before a fire. Released, a prisoner first sees the puppets, then is dragged outside and pained by the daylight, eventually seeing reflections, then objects, then the sun itself (the Good). If he returns to liberate the others, his eyes are unaccustomed to darkness; the cave-dwellers think he has gone mad and might kill him. The image fuses epistemology with the political fate of the philosopher — Socrates's own.
543a–592b
Books VIII–IX — decline of constitutions and the tyrannical soul
Socrates traces the decline of constitutions and the parallel decline of soul-types. Aristocracy (rule by the best, philosopher-kings) decays into Timocracy (rule by spirited honor-lovers, like Sparta), where Spirit overruns Reason. That decays into Oligarchy (rule by the wealthy), where moneymaking Appetite dominates. Oligarchy decays into Democracy (freedom-obsessed rule by the demos), where all desires are equally honored and there is no order. Democracy, in the chaos of unlimited freedom, breeds a champion who promises protection — the Tyrant emerges, ruling by terror. Each city-type has its corresponding soul. The tyrannical soul is enslaved to a single master Eros (an obsessive passion), surrounded by fear, the most miserable of all conditions despite the appearance of supreme power.
580c–588a
Book IX — three proofs of justice's happiness
Three arguments that the just life is happier than the unjust. (1) The argument from the city-soul analogy: the philosopher-king is happiest as the aristocratic city is best; the tyrant most wretched as the tyrannical city is worst — happiness tracks the order of the soul. (2) Each soul-part has its own pleasures (gain for Appetite, honor for Spirit, learning for Reason); only the philosopher has experience of all three and can judge — and he prefers Reason's pleasures, which are most real. (3) Most pleasures of the body are mere relief from pain, like the relief of scratching an itch — neutral states felt as pleasure only by contrast. The pleasures of the soul, especially of contemplating the unchanging Forms, are pleasures of being filled with what truly is, and so are the most real pleasures available.
595a–621d
Book X — poetry's banishment and the Myth of Er
Plato returns to poetry, banished as imitation of imitation: the painter imitates the carpenter's bed, which imitates the Form of Bed; poetry is therefore three steps removed from reality, and worse, it appeals to Spirit and Appetite over Reason. Then the rewards of justice in this life and beyond. The Myth of Er: a Pamphylian soldier killed in battle revives on the funeral pyre and reports the afterlife. Souls are judged, punished or rewarded for a thousand years, then returned to choose new lives. The choices reveal character: those merely habituated to virtue (without philosophy) often choose disastrous lives — Odysseus, sick of fame, picks the life of an obscure private man and is glad. Only the philosophically educated chooses wisely. Each soul drinks from the river Lethe (forgetfulness) before being reborn. The dialogue ends with a final exhortation: hold to the upward path; practice justice with intelligence in every way.
Phaedrus
Under a plane tree outside Athens, Socrates discusses love and rhetoric with Phaedrus. Contains the myth of the soul as a charioteer with two horses, the recovery of Beauty through erotic recollection, and a famous critique of writing vs. living spoken philosophy.
InterlocutorsSocratesPhaedrus
227a–234c
Lysias' speech — the non-lover is preferable
Phaedrus has been at the home of Lysias and is leaving with a copy of a speech he is dying to share. Outside the city walls, by a plane tree on the Ilissus, he reads the speech to Socrates. Lysias's argument: a beautiful boy should grant his favors to a non-lover rather than a lover. Lovers are irrational, jealous, possessive, full of regret afterward, and an embarrassment to be seen with. Non-lovers are calm, rational, consistent, and useful. The speech is brilliantly clever and morally bankrupt — a perfect specimen of sophistic rhetoric. Phaedrus is dazzled.
237a–241d
Socrates' first speech — the harm of eros
Socrates, claiming to do better, gives his own speech against love — covering his head in shame as he speaks. He distinguishes two ruling principles in us: rational desire for the good (sōphrosynē), and irrational desire for pleasure (hubris). When the latter takes over love of beauty, it becomes Eros — a kind of disease in which the lover possessively reduces the beloved to a means of his pleasure, fearing the beloved's growth in wisdom and independence. Suddenly Socrates stops mid-speech — his daimonic sign warns him. The speech blasphemed against Eros, who is a god. He must purify himself with a recantation.
243e–257b
The Palinode — the great hymn to Eros
Socrates begins the Palinode (recantation). The previous speeches assumed madness is bad — but in fact some of the greatest blessings come through madness sent by the gods. Four kinds: prophetic (Apollo's, as at Delphi), telestic/ritual (Dionysus's, healing through ecstasy), poetic (the Muses', producing poetry beyond mortal art), and erotic (Aphrodite's and Eros's). Erotic madness, properly understood, is not pathology but the soul's recognition of divine beauty. Sanity at the cost of seeing nothing beyond the visible is not the higher state.
246a–257b
The myth of the soul — the charioteer and two horses
Socrates offers the great myth of the soul. The soul is like a chariot pulled by two winged horses: a noble white horse (spirited, honor-loving) and an unruly black horse (appetitive, lust-driven), guided by a charioteer (reason). All souls follow the gods in heaven, glimpsing the Forms in the 'super-celestial place' beyond the heavens. But the unruly horse causes most souls to lose their wings and fall to earth, born into bodies. The vision of true beauty has been mostly forgotten. When the embodied soul encounters earthly beauty, the wings begin to grow back through painful itching; the lover trembles, sweats, suffers — recovering recollection of the Form of Beauty. True love between philosophical souls becomes the joint cultivation of wings — moral progress through shared ascent.
259e–274b
The rhetoric of Socrates — good vs. bad rhetoric
Turning to rhetoric, Socrates argues that genuine rhetoric — psychagōgia, the leading of souls — requires (1) knowing the truth about the subject, (2) knowing the kinds of souls and which arguments persuade which kinds, and (3) practicing the art on real audiences. Lysias's speech and the textbooks of contemporary rhetoricians fail all three: they are technique without knowledge of subject or hearer, mere collections of devices. Real rhetoric is closer to philosophy than to current practice. The orator is a doctor of the soul.
274c–279c
The critique of writing — the Theuth myth
Finally, the famous critique of writing. Egyptian Theuth (Thoth) presented his invention of letters to King Thamus, claiming it would make people wiser. Thamus refused: it will produce forgetfulness in the learner, not memory; the appearance of wisdom, not its reality. Writing cannot answer questions, defend itself, or distinguish suitable hearers. It rolls about indiscriminately. Genuine philosophy is the living word planted in a soul, capable of defense and growth, transmitted through dialectic. A writer who knows truth uses writing only as a 'garden of Adonis' — a memorandum, not a serious harvest. The dialogue itself, of course, is a written text — and Plato's writing of dialogues, with all their dramatic life, may be the closest writing can come to philosophical conversation.
Late period
Theaetetus
A searching investigation into the nature of knowledge. Three definitions are proposed and refuted: knowledge is perception, knowledge is true belief, knowledge is true belief with an account.
InterlocutorsSocratesTheaetetusTheodorus
148e–151d
The midwifery metaphor
Theodorus, the great mathematician, points out the brilliant young Theaetetus, of whom Socrates becomes immediately fond. Socrates describes his characteristic method through the midwifery metaphor. His mother Phaenarete was a midwife; Socrates is the same for souls. He himself is barren — he produces no doctrines — but he assists others in giving birth to their thoughts. Crucially, after delivery he must test each newborn idea to see whether it is a healthy child or a wind-egg (an unfertilized appearance). Many young men have hated him for ruining their pet beliefs — but the test is necessary.
151e–160e
First definition — knowledge is perception (Protagoras)
Theaetetus's first answer: knowledge is perception (aisthēsis). Socrates assimilates this to Protagoras's slogan ('man is the measure of all things — of those that are, that they are; of those that are not, that they are not') and a Heraclitean ontology of universal flux. On this view, perception is always true for the perceiver, and what appears is what is — for that perceiver. Refutation: this would make hallucinations and dreams knowledge; it cannot account for memory, since we know things we are not currently perceiving; and the senses themselves only deliver sensations — judgment about being, sameness, equality, beauty requires the soul thinking by itself, not perceiving.
161c–168c
Refutation of Protagoras
Socrates lets the ghost of Protagoras defend himself, then strikes. The most damaging move: if every belief is true for the believer, then the belief 'Protagoras is wrong' — held by his many opponents — is true for them. Protagoras is therefore wrong by his own doctrine. Furthermore, real life requires expert opinion: the doctor's predictions about future health are reliable, the layman's are not. We don't all defer to the layman. Even Protagoras took fees for teaching, presupposing he knew something his clients did not. The relativist self-refutes.
172c–177c
The Digression — the philosopher vs. the man of affairs
A famous set piece, introduced as a 'digression' but philosophically central. Socrates contrasts two lives. The man of affairs (the lawyer, the politician) is always hurrying under the pressure of the water-clock in court, arguing about particular cases, flattering juries, with no leisure to pursue a question to its end — his soul is stunted and warped by servility. The philosopher, by contrast, doesn't even know the way to the agora; he is mocked as useless and laughed at when he falls into a well while stargazing (the Thales anecdote). But the philosopher's soul is free to follow an argument wherever it leads. The digression culminates in the declaration that the aim of philosophy is 'becoming like god as far as possible' (homoiōsis theō, 176b) — the first clear formulation of this ideal, which became central to later Platonism and Neoplatonism. The 'godlike' life is the life of justice and wisdom; evil is not among the gods but haunts mortal nature necessarily.
179c–183c
Refutation of Heraclitean flux
Socrates examines the Heraclitean ontology backing Protagoras. If everything is in radical flux — changing in every respect at every moment — then nothing can be 'this' or 'such' for long enough to be perceived or named. The very thing we are about to call 'white' becomes another color before we finish saying it. Language presupposes stability; flux undermines it. So perception cannot be knowledge, because knowledge requires its objects to remain themselves long enough to be grasped.
187a–201c
Second definition — knowledge is true belief
Theaetetus's second answer: knowledge is true belief (alēthēs doxa). First Socrates digresses to ask how false belief is even possible — a long puzzle invoking a wax-tablet metaphor (memory as imprints) and an aviary metaphor (knowledge as captured birds, which we may seize the wrong one of). The puzzle isn't fully resolved. Then he refutes the definition: a jury persuaded by a skilled orator to a true verdict, but without having witnessed the events, has true belief but not knowledge — they could just as easily have been persuaded of a false verdict. Knowledge must include something that secures the truth, not merely happen to be true.
201c–210a
Third definition — true belief with an account (logos)
Theaetetus's third answer: knowledge is true belief plus an account (logos). 'Account' is examined in three senses. (1) Putting your thought into spoken words — but everyone non-mute does this for any belief, true or false. (2) Enumerating the elements: but knowing each letter of a name doesn't itself make you know the name as a whole. (3) Stating what differentiates the thing from everything else (a definition). But to know the differentia is to know the thing — so 'knowledge is true belief plus knowledge' — which is circular. None of the three interpretations of logos converts true belief into knowledge.
210a–210d
Aporia — the dialogue ends in failure
Theaetetus has been delivered of three plausible-looking offspring, all of which Socrates has examined and found to be wind-eggs. The dialogue ends in aporia — no positive account of knowledge has emerged — but the work is genuine: Theaetetus has been freed from false confidence and shown the difficulty of the question. Socrates leaves to face the indictment Meletus has brought; the next day he and Theaetetus will meet again with a visiting Stranger from Elea (the Sophist). Plato's epistemology continues across dialogues; the Theaetetus clears the ground.
Parmenides
The most technically demanding of Plato's dialogues. The historical Parmenides demolishes a young Socrates' Theory of Forms with devastating objections, then models correct philosophical method in an extended logical exercise on the One.
InterlocutorsParmenidesZenoSocratesAristoteles
126a–130a
The setting — Socrates meets Parmenides
An elaborately framed narration. The dramatic date is around 450 BCE — Socrates is about 19 or 20, Parmenides about 65, Zeno about 40. They meet at the Panathenaea (Athens's great festival of Athena). Zeno has just read a treatise defending Parmenides's monism by reductio: if there are many beings, they must be both like (in some respect) and unlike (in another), which Zeno deems contradictory. The young Socrates rises to suggest a solution: there is no contradiction in a thing 'partaking of' both Likeness Itself and Unlikeness Itself, since the contradiction would only arise in the Forms themselves. He has just introduced his Theory of Forms to its sternest critic.
130a–135c
Interpretations of the Forms before the logical exercise
Parmenides systematically draws out and challenges several distinct interpretations of the Theory of Forms. (1) Scope: Are there Forms for everything — including hair, mud, dirt, and undignified things? Young Socrates hesitates; Parmenides gently warns that mature philosophy will not allow such squeamishness. (2) The Whole/Part Dilemma: How does a particular 'partake' of a Form? If of the whole Form, then a single Form is wholly present in many places at once (an apparent absurdity). If of a part, the Form is divisible — and partaking of a part of Largeness would not make a thing large in the Form's own way. (3) Forms as Mere Thoughts (conceptualism): Could Forms be thoughts in minds? But thoughts must be thoughts OF something real; this just pushes back the question. Furthermore, if everything that participates is a thinker, then everything thinks — absurd. (4) Forms as Paradigms: Perhaps Forms are patterns and particulars are likenesses of them. But likeness is symmetrical: if the particular is like the Form, the Form is like the particular — and they share a property, requiring a further Form to explain that resemblance. This leads directly into the Third Man.
132a–132b
The Third Man Argument
The Third Man Argument (so named because Aristotle calls it that). Many large particulars share a Form of Largeness; the Form explains why they are all called large. But now consider the original Form together with the particulars — if they all appear large, what explains that common appearance? Apparently a higher Form. And so on without end. The argument exploits two assumptions: (a) self-predication (the Form of Largeness is itself large) and (b) non-identity (the Form is different from the particulars). Together they generate an infinite tower of Forms. Plato is here exposing real internal tensions in the middle-period theory — and he gives Socrates no good answer.
133b–135b
Other objections — knowledge of Forms
Two further objections. The Greatest Difficulty: if Forms are fully separate from us, then they belong to a separate domain — and our knowledge, being of things in our world, cannot reach them. Conversely, the gods, whose knowledge is of Forms, could not know things in our world. The radical separation that gives Forms their distinctive role also threatens the very intelligibility of the theory. Parmenides concludes: a young man's mistakes — but anyone serious about the Forms must answer these objections, and the Theory of Forms cannot survive in its naive form.
137c–166c
The second part — the exercise on the One
Despite his criticisms, Parmenides insists Socrates must train rigorously in dialectic before continuing. He demonstrates by example: take a hypothesis (his own — 'the One is') and trace consequences both for the One and for the others, then take the contradictory hypothesis ('the One is not') and do the same; do this for each predicate. He works through eight massive deductions about the One. Hypotheses 1 and 2 examine 'if the One is one' versus 'if the One is being'; subsequent ones examine the One's relations to other things, and the corresponding cases for 'if the One is not.' The deductions produce mutually contradictory results — the One has every property and its negation depending on which sense is taken. Whether this is meant to refute monism, model dialectical method, or hint at a positive theology has been debated for 2,500 years.
Philosophical significance
The dialogue is Plato's most rigorous philosophical self-criticism — possibly preparing the ground for revisions in the Sophist and Philebus. Neoplatonists, especially Plotinus, treated the eight hypotheses as a positive metaphysical system, with the first hypothesis ('the One that is utterly One') as the supreme principle beyond Being — generating their entire emanationist hierarchy. Modern analytic philosophy has mined the dialogue for early formulations of paradoxes of self-reference, predication, and identity. There is no consensus on the dialogue's positive purpose.
Sophist
The Eleatic Stranger uses the method of division (diaeresis) to define the sophist and, along the way, solves the ancient puzzle of how false speech and not-being are possible — overcoming Parmenides.
InterlocutorsThe Eleatic StrangerTheaetetusTheodorusSocrates
216a–221c
The method of diaeresis — division
The Eleatic Stranger introduces the method of collection (synagogē) and division (diairesis). Take a genus, then divide it into two natural species, then divide one of those again, and so on, until you reach the species you want to define — capturing it as the bottom node of a binary tree. To warm up, the Stranger demonstrates on the harmless angler (fisherman): art (productive vs. acquisitive); acquisitive (by exchange vs. by capture); capture (open or hidden); hunting (of inanimate or animate); animate (water-dwelling vs. land-dwelling); etc. The angler is reached as one specific terminal node. The method, while artificial, sharpens the demand for distinguishing genus from species.
221c–231b
Six definitions of the sophist
The same method is applied six times to the sophist, each time arriving at a different definition: (1) a hunter of wealthy young men for pay; (2) a wholesale merchant of soul-goods (transporting learning between cities); (3) a retailer of soul-goods (selling locally); (4) a craftsman selling his own products; (5) a competitor in eristic debate for profit; and (6) a purifier of souls who removes false conceits about knowledge by cross-examination — which suspiciously matches Socrates himself. The Stranger has put the elenctic method in the same genus as sophistry; the differentia between Socratic philosophy and sophistry must come from somewhere outside the genus they share.
236d–242b
The problem of not-being and false speech
The seventh and final attempt requires confronting a deep problem. The sophist makes images and illusions — verbal copies of reality that aren't real. But an image (eikōn) seems to be in some way (it exists as an image) yet not be in another way (not the original). Worse: false speech says what is not the case — but how can speech say what is not? Parmenides forbade thinking or speaking 'what is not' (to mē on) at all — non-being is unutterable. If sophistry depends on falsity and image-making, and these depend on non-being, then either sophistry doesn't exist or Parmenides was wrong.
242b–259d
Overthrowing Parmenides — not-being as difference
The Stranger commits philosophical patricide against 'father Parmenides.' Not-being need not mean absolute non-existence (the impossible 'opposite' of being). It can mean difference (heterotēs). When we say 'X is not large,' we do not mean X is utterly nothing; we mean X is other than large — different from largeness. Not-being is woven through being itself. Falsehood is now intelligible: a false statement says of what is, things that are not — meaning it attributes properties different from the ones the subject actually has. ('Theaetetus is flying' attributes a property different from those Theaetetus actually has.) This solution is one of the great achievements of ancient logic.
253b–259d
The communion of kinds — the greatest kinds
To make the solution work, the Stranger introduces a metaphysics of how Forms (or 'kinds,' genē) combine and exclude each other. Five 'greatest kinds' are isolated: Being, Sameness, Difference, Motion, Rest. Motion partakes of Being (it exists), of Sameness (with itself), of Difference (from Rest, from itself qua not-Rest, from Being qua not-being); but Motion does not partake of Rest (its opposite). This 'communion' or 'combination' (koinōnia, symplokē) of kinds is what makes meaningful predication possible. Being itself is woven through everything; Difference makes negation, otherness, and falsehood intelligible; Motion and Rest are mutually exclusive.
263d–268d
Final definition of the sophist
Returning to the original task armed with the new metaphysics, the Stranger reaches the seventh and final definition. Image-making divides into faithful copying (likeness-making) and apparition-making (creating false appearances that look like the original from a misleading perspective). Apparition-making divides into instrumental (using tools) and mimetic (using oneself). Mimetic divides into the knowing imitator (who actually knows what he imitates) and the conceited imitator (who imitates without knowing). The sophist is the conceited mimic operating in private rather than public, contradicting in short speeches rather than long. The genuine philosopher can finally be distinguished from this elusive figure: the philosopher knows.
Statesman
Continuing from the Sophist, the Eleatic Stranger uses division to define the Statesman. Introduces 'the mean' (the right measure), the myth of the reversed cosmos, and a nuanced account of constitutions.
InterlocutorsThe Eleatic StrangerYoung SocratesTheodorusSocrates
258b–267c
Definition by division — the statesman as herdsman
The Eleatic Stranger and the young Socrates resume immediately. Politics belongs to the productive arts (it produces something — a well-ordered citizenry); to the cognitive arts (it requires knowledge, not mere physical labor); to the directing arts (it commands rather than serves); and to those that direct other living things in groups. The statesman is therefore a kind of herdsman — a 'tender' of the human herd. But this groups him with tyrants and even with gods (who tend mortals from above), so the definition is too broad. We need to refine.
268d–277c
The myth of the reversed cosmos
The Stranger introduces the myth because the previous definition — the statesman as herdsman — has failed. It depicted a figure too grand (a divine shepherd rather than a human ruler) and too broad (lumping the statesman with farmers, bakers, doctors, and gymnasts who also claim to 'tend' humans). To expose these errors, the Stranger tells a cosmological myth. There are two cosmic ages, alternating. In the Age of Cronos, the god steers the cosmos directly: humans need no political art because divine providence nurtures them — they are born from the earth, age in reverse, and live without labor or self-governance. Then the god releases the helm; the cosmos reverses direction; humans are now born from each other, age forward, and must govern themselves. Our current age (the Age of Zeus) is this second era. The myth makes explicit that the 'herdsman' model belongs only to the divine age: no human ruler possesses godlike superiority over other humans the way a shepherd rules sheep. In our age, the statesman must be redefined — not as a nurturer but as something else entirely (the dialogue will settle on the weaver). The myth thus serves as a methodological correction, narrowing the search by eliminating the divine-caretaker model and forcing a fresh approach.
279a–311b
The statesman as weaver — the political art
After eliminating various rivals (rhetoricians, judges, generals are mere subordinates), the statesman is finally identified through the analogy of weaving. Weaving combines two kinds of thread — warp (firm, taut) and woof (soft, flexible) — into a single stable cloth. The city analogously contains two natural temperaments: the bold/courageous (warp) and the moderate/orderly (woof). Each, alone, fails: pure boldness leads to faction and recklessness; pure moderation leads to passivity and political suicide. The statesman's art binds the two together, choosing rulers from both temperaments and arranging marriages between them. The constitution is a 'fabric' that mixes opposed virtues.
283c–285c
The doctrine of the mean — measurement
A major philosophical excursus on the Mean (to metrion). There are two kinds of measurement: relative measurement (X is greater or smaller than Y) and measurement against a standard of fitness (X is the right size for the purpose). All true arts depend on the second kind: the cobbler measures the shoe to the foot, not just to other shoes; the doctor measures dosage to patient; the statesman measures policy to the city's good. Without the mean, no productive art is possible. Plato thus grounds an objective standard of 'the appropriate' that anchors political expertise and every other genuine art.
285d–287a
The real purpose — dialectic, not the statesman
The Stranger pauses to make a remarkable methodological declaration. The primary purpose of this entire inquiry is not to define the statesman but to make the interlocutors better dialecticians about everything — the statesman is merely the exercise subject. Just as students learning to read practice on simple syllables before harder ones, the long digressions (the myth, the weaving analogy, the measurement excursus) are deliberate training in method. We pursue the statesman for the sake of becoming better at dividing any subject into its natural kinds. This is one of Plato's clearest statements about the priority of dialectical skill over any particular subject-matter — and it retroactively reframes the entire dialogue as a methodological exercise.
291d–303c
Classification of constitutions
Constitutions are classified by three criteria: number of rulers (one/few/many), willingness of the ruled, and presence of law. This yields six types: rule of one with law (kingship) or without (tyranny); of few with law (aristocracy) or without (oligarchy); of many with law and without (two forms of democracy). But all six are imitations of a seventh, ideal form: rule by a genuinely knowledgeable statesman, who governs even contrary to written law if the situation demands — because his judgment perfectly fits the case, while law is always a clumsy general rule.
305e–311c
Law and the second-best rule
Since the truly knowledgeable statesman is exceedingly rare, second-best is strict rule of law: imperfect general rules, rigorously applied. Where law rules, the best of the imitative constitutions is monarchy under law (kingship); the worst is tyranny. Where law does not rule, the rankings reverse: among lawless constitutions, democracy is least bad (because the most diffuse power does the least harm), and tyranny is the most ruinous. The dialogue closes by reiterating the weaver-image: the statesman's final task is binding citizens through right opinions about the noble, the good, and the just, which alone produce real civic friendship.
Timaeus
Plato's major work on natural philosophy. Timaeus delivers a long 'likely story' about how the Demiurge made the cosmos, modeling it on eternal Forms. Contains the World-Soul, the elements as geometry, and the human body and soul.
InterlocutorsSocratesTimaeusCritiasHermocrates
17a–27b
Prologue — recap of the Republic
Socrates, having yesterday described the ideal city of the Republic, asks his hosts to show that city in action — engaged in great deeds. Critias offers to do so by recounting an ancient war between primeval Athens and Atlantis, drawing on Egyptian records. But first, Timaeus of Locri — a Pythagoreanizing astronomer-philosopher — will set the stage by describing the origin of the cosmos and humanity. The framing puts cosmology before history: we cannot know the proper order of human life until we know the order of the world.
27d–37c
The Demiurge and the model
Timaeus distinguishes what is (eternal Being, grasped by reason) from what becomes (the world of generation, grasped through opinion plus perception). The cosmos belongs to becoming, so its account can only be a 'likely story' (eikōs mythos). The Demiurge — a divine craftsman, 'father and maker' of all — was ungrudging and wished everything to be as good as possible. Looking to the eternal Forms as model, he imposed rational order on a pre-existing chaotic substrate. The cosmos is therefore a single, intelligent, ensouled, spherical living creature, fashioned in the image of the eternal Living Creature (the totality of intelligible Forms).
35a–40d
The World-Soul — mathematical structure
The World-Soul is fashioned first, before the body, from a blend of three ingredients: divisible Being, indivisible Being, divisible Sameness, indivisible Sameness, divisible Difference, indivisible Difference. The Demiurge stretches this soul-stuff according to musical ratios (2:1, 3:2, 4:3 — the octave, fifth, and fourth) and divides it into two great circular bands: the outer Circle of the Same (carrying the fixed stars) and the inner Circle of the Different (carrying the seven planets). The motion of these circles measures and produces Time — itself a moving, numbered image of unmoving Eternity.
41d–44d
The creation of the human soul
The Demiurge created the immortal part of the human soul from the same materials as the World-Soul, but already diluted. Each soul was placed in its own star, shown the laws of fate, and told that incarnations would be neutral if souls retained their original natures, but would degenerate if vice took hold — moving men into women, then into beasts, until reason was recovered. The head is spherical (mirroring the cosmos) and is the seat of the rational soul; the rest of the body is its vehicle. Lesser gods were entrusted with fashioning the mortal parts of the soul (spirit and appetite) and the body.
48e–52d
The Receptacle (Chora)
Plato introduces a third metaphysical principle besides Forms and copies: the Receptacle (hypodochē) or Nurse of becoming, also called Space or Khōra. It receives all qualities and forms but has none of its own — a wholly featureless 'in which' all becoming takes place. It is grasped neither by intellect (reserved for Forms) nor by perception (which sees only sensibles), but by a kind of 'bastard reasoning' — as in a dream. The Receptacle resolves a problem: how can the same elements transform into one another while remaining 'one cosmos'? They are configurations within a single underlying space. The doctrine deeply influenced Aristotle's matter-form analysis and modern philosophical theology.
53c–57d
The four elements as geometric solids
Drawing on Pythagorean speculation, Timaeus assigns each of the four traditional elements to one of the four regular solids whose faces can be constructed from triangles. Fire = tetrahedron (sharpest, most mobile); Earth = cube (most stable); Air = octahedron; Water = icosahedron. The fifth solid, the dodecahedron, the Demiurge used 'for the whole, embroidering the constellations.' These solids are composed of two basic right triangles (the half-square and the half-equilateral). When particles are broken, the underlying triangles can recombine into other solids — explaining how fire, air, and water can transform into one another (earth, whose cube faces use a different triangle, is excluded from these transformations). Plato thus offers an early geometrical theory of matter.
81e–87b
The human body — disease and health
An extensive medical anatomy and pathology. Bones, marrow, sinews, flesh, skin, hair are described, each with its function. Disease has three sources: the elements falling out of their proper proportion; the secondary substances of the body (blood, marrow) deteriorating; or breath, phlegm, and bile causing disorder. Mental disease arises from physical imbalance OR from bad upbringing in a faulty constitution. Health of body and soul together requires balanced motion: gymnastic for the body, philosophy and music for the soul. Excess of any one — too much body work, too much study — produces disease.
Philebus
Socrates debates Philebus and Protarchus about whether pleasure or knowledge is the good life. Introduces a sophisticated metaphysical framework of Limit, Unlimited, Mixture, and Cause.
InterlocutorsSocratesProtarchusPhilebus
11a–22e
The contest — pleasure vs. knowledge
The dialogue opens mid-debate. Philebus (who has spoken the night before) defends hedonism: pleasure (hēdonē) is the good for all living beings. Socrates defends a competing view: knowledge, reason, and intelligence are better. Philebus essentially withdraws from the conversation; his student Protarchus carries on. Socrates poses a thought experiment: would you choose a life of pure pleasure with no knowledge, awareness, or memory of the pleasure? No — that would be the life of a mollusk. A life of pure intellect with no pleasure? Also unappealing. The good life must be a mixture. The remaining question is which ingredient is more responsible for its goodness.
23c–27c
The four categories — Limit, Unlimited, Mixture, Cause
Socrates introduces a metaphysical schema of four categories. (1) Apeiron (Unlimited): pure continua of more-and-less — hotter/colder, faster/slower — without inherent measure. (2) Peras (Limit): determinate proportions, ratios, fixed amounts. (3) The Mixture of the two: when the right ratio is imposed on the unlimited, you get health (right proportion of hot and cold), music (right ratio of high and low), seasons (right balance of weather), beauty. (4) The Cause of the mixing: the agency that imposes Limit on the Unlimited — which Socrates identifies with cosmic Intellect (Nous), king of heaven and earth, the source of all order. This four-fold scheme is the most developed late-Platonic metaphysics outside the Timaeus.
31b–55c
The classification of pleasures
Pleasures are sorted. Mixed pleasures arise from prior depletion: hunger satisfied, itch scratched, anger vented. They depend on the contrast with pain and are therefore partly illusory — what feels like pleasure is mere relief, a return to a neutral state mistaken for a positive good. Pure pleasures arise without prior pain: the pleasures of contemplating beautiful pure shapes (circles, straight lines), pure colors, pure sounds, pure smells, and the pleasures of learning. False pleasures are also distinguished: pleasures that rest on false beliefs (anticipating something good that won't happen), or that overestimate their own magnitude.
55c–59d
The classification of knowledge
Knowledge is sorted by precision. Practical arts (carpentry, agriculture) involve much guesswork; precise crafts (using rule, compass, balance) are higher. Pure mathematics (counting and measuring abstracted from sensible particulars) is higher still. Highest of all is dialectic — the philosopher's knowledge of Forms and the eternal causes. The hierarchy lets us identify which kinds of knowledge contribute most to the good life: not the knowledge of changeable particulars but knowledge of unchanging realities.
64a–67b
The rank order of goods in the mixed life
Final ranking of the goods that constitute the best human life. (1) Measure (metron), the timely, the appropriate — the very principle of proportion. (2) The proportionate, the beautiful, the perfect, the sufficient. (3) Reason and intelligence. (4) Sciences, arts, and right opinion. (5) Pure pleasures (of beauty, learning, harmless sensation). Mixed pleasures with pain do not even make the list of unconditional goods. Pleasure has lost its top spot — it ranks below intellect and far below measure itself, but the wise life still includes the right pleasures in their proper place.
Critias
A companion to the Timaeus, left unfinished. Critias recounts the story of ancient Athens and Atlantis: their conflict, Atlantis' hubris and destruction, and the noble simplicity of ancient Athens. The dialogue breaks off mid-sentence.
InterlocutorsCritiasSocratesTimaeusHermocrates
106a–108d
The story of Atlantis — its source
Critias reaffirms the ancestry of his story. Solon, the Athenian lawgiver, heard it in Egypt from the priests of Saïs. The priests told him Egyptian records went back 8,000 years and included an event Athenians had forgotten because their own records were destroyed by floods: 9,000 years before, a great war between Athens and the empire of Atlantis — a vast island beyond the Pillars of Hercules (the Strait of Gibraltar). Solon brought the story home but never finished writing it. It was passed down through Critias's family. The frame insists this is genuine ancient history, not myth.
109b–112e
Ancient Athens — the ideal city in history
Ancient Athens, in this telling, embodied the Republic's ideal in actual history. The territory of Attica was vastly more fertile (later eroded by deluges to its present rocky condition). The city had a small population of about 20,000 warriors, occupying the Acropolis only, supported by an agricultural class — a structure recognizably that of Republic V. They had no private property, lived simply, were trained in arms by both men and women, and were dedicated to the practice of virtue. Their excellence is what enabled them to repel the Atlantean invasion.
113c–118b
Atlantis — its geography and constitution
Atlantis, by contrast, was an extraordinary marvel of engineering and wealth. Poseidon, allotted the island, fathered ten sons by the mortal Cleito; he enclosed her dwelling with concentric rings of water and land. The ten sons became ten kings of ten regions, with the eldest (Atlas) reigning over the central royal city. The capital had elaborate concentric harbors, a great temple of Poseidon plated with orichalcum (a legendary precious metal, perhaps a gold-copper alloy), hot and cold springs, vast gardens. Their constitution rested on the inscribed pillar in Poseidon's temple, on which were engraved laws; the kings met every fifth and sixth year, swore oaths over a sacrificed bull, and judged together — a federal monarchy under sacred law.
120d–121b
The corruption of Atlantis
Across generations, Atlantis declined. The divine portion in the kings was diluted by mortal admixture, and human nature came to dominate. The Atlantean kings, while still outwardly admirable, became inwardly corrupt: they grew greedy, given to outward ostentation, and unjust. To anyone who could discern the truth, they were obviously fallen; to most observers, they appeared most blessed. Zeus, the god of justice, saw the corruption and resolved to punish them, that the chastisement might restore them. He summoned the gods to assembly...
121b–121c
The dialogue breaks off
And here the text breaks off, mid-sentence: 'Zeus collected all the gods together... and when he had collected them, he spoke as follows...' Whether Plato died before completing it, abandoned the project, or it was lost to later transmission is unknown. The Atlantis material — including the dramatic destruction by earthquake and flood, hinted at in the Timaeus — is forever incomplete. The Critias remains one of the most tantalizing fragments in Greek literature, generating two and a half millennia of speculation about what 'really' lay behind Plato's account.
Laws
Plato's longest dialogue — and probably his last. Three old men walk to the cave of Zeus on Crete and discuss legislation for a new city ('Magnesia'). A realistic second-best city. Socrates does not appear; the lead speaker is the Athenian Stranger.
InterlocutorsThe Athenian StrangerCleiniasMegillus
624a–674c
Books I–II — the purpose of law and education
An old Athenian (the Athenian Stranger) walks toward the cave of Zeus on Crete with a Cretan (Cleinias) and a Spartan (Megillus). They begin discussing Cretan and Spartan laws, both designed primarily for warfare. The Stranger demolishes this premise: a city's laws should aim at the whole of virtue, not merely at conquest. Education in virtue means training the right responses of pleasure and pain in the young. Music, poetry, and dance shape these responses — the lawgiver must control them. Then a long discussion of the symposium: well-regulated wine-drinking, contrary to Spartan suspicion, is a controlled testing ground where the old can rehearse their virtue under the loosening pressure of drink.
676a–702e
Book III — constitutional history and the mixed constitution
Book III turns to constitutional history. After ancient floods, civilizations rebuilt slowly, beginning with patriarchal clans. The Stranger surveys the failures of pure monarchy (Persia, where the kings became despots) and pure democracy (Athens, where freedom became license). The successful constitutions — Sparta's, with its dual kings, council, and ephors (elected magistrates who checked royal power) — mixed monarchy and democracy. The principle: each constitutional element must be limited by another. This is one of the earliest formulations of the mixed constitution that influenced Aristotle, Polybius, Cicero, and the framers of modern constitutions.
704a–724b
Book IV — the founding of Magnesia — the rule of law
Cleinias reveals that Crete is founding a colony — Magnesia — and they are charged with drafting its laws. Excellent: they can frame an ideal that is also realistic. The Stranger states a fundamental principle: the new city must be ruled by law, not by men, because men placed above law inevitably corrupt. The lawgiver's job, however, is not just to compel but to persuade. Each major law must have a preamble (prooimion) — a preface explaining its rationale, the goods it secures, the harms it averts. The lawgiver as doctor of free citizens, not master of slaves: he uses both reason and force, but reason first.
726a–747e
Book V — character, property, and equality
Book V opens with a meditation on the soul as the truest possession, and ends with concrete demographic and economic structures. The city will have exactly 5,040 households on 5,040 plots of land — the number chosen for its divisibility (it has 60 divisors, including all numbers from 1 to 12 except 11). Each plot has two parts (one near the city, one near the border), inalienable, passed to a single heir; the lawgiver must regulate succession to maintain the number. Wealth is capped: no citizen may have more than four times the value of the basic plot. There are four wealth-classes for political purposes, but extreme inequality is forbidden.
751a–824a
Books VI–VII — offices, marriage, and education
Books VI and VII detail the constitutional framework and the educational system. Officials (Guardians of the Laws — 37 elected men over 50; the Council of 360; military officers; agronomoi (rural overseers); astynomoi (city overseers); agoranomoi (market overseers); etc.) are chosen by various combinations of election and lot, with strict accountability. Marriage laws regulate ages, procedures, dowries; women undergo similar education and military training as men. The educational curriculum runs from infant care through choral dance, music, gymnastic, letters, mathematics, geometry, and astronomy — the last two not just for utility but because they reveal the rational divine order of the cosmos. Atheist astronomy (the heavens as random) is corrupting; the truth is that they manifest divine reason.
828a–850c
Book VIII — festivals, agriculture, and military
Festivals run on a strict calendar of 365 days, each devoted to specific gods, with prescribed sacrifices, choral performances, and athletic competitions — civic life is structured by ritual. Agriculture is regulated to maintain self-sufficiency; the use of public springs and boundaries follows strict rules. Military training is universal: men, women, boys, and girls all train monthly. Any citizen who avoids serving in war is severely punished. The aim is constant readiness without an aggressive foreign policy.
853a–874d
Book IX — criminal law
Book IX develops a detailed penal code covering temple-robbery, treason, homicide, assault, and various forms of fraud. The philosophical key: punishment is not retribution but cure. All wrongdoing is in some sense involuntary (the Socratic principle), but the Stranger refines this: voluntary wrong harms the doer's soul more, and so the penalties should aim at correction. Where cure is impossible, execution is mandated as a deterrent and to free the criminal from a soul too damaged to bear. Detailed rules govern private suits, witness testimony, false accusation, and so on.
884a–910d
Book X — theology and the proof of the gods
Book X is the philosophically weightiest section of the Laws and one of the great theological texts of antiquity. The lawgiver must combat three forms of impiety, each progressively less destructive: (1) Atheism — denying that gods exist; (2) Deism — granting gods exist but denying they care about human affairs; (3) Corruption — granting they care but believing they can be bought off by sacrifices and prayers. Each is refuted philosophically, not just legally. Against atheism, the Stranger develops what is essentially the first systematic argument from motion in Western literature: motion is divided into kinds, of which only soul-motion (self-motion) can be the original cause; soul is therefore prior to body, the source of all change; since the cosmos exhibits orderly, rational motion, the soul moving it must be rational and good — and this is what we mean by 'God.' The gods' perfect goodness rules out indifference (they care for the smallest things, as a doctor for the smallest organ) and bribery (just gods do not accept bribes, and bribery from sacrifices is monstrous to suppose). Impiety carries severe penalties: solitary confinement for the curable, death for incurable cases. The book grounds the entire legal structure in cosmic theology.
913a–969d
Books XI–XII — commercial law and the Nocturnal Council
The final two books wrap up commercial law (contracts, inheritance, debt, deposits, slaves), funeral regulations (modest, not ostentatious), and oversight of religious practice. The dialogue ends with the Nocturnal Council — an assembly of the wisest senior citizens (along with their best young apprentices) who meet before dawn to study theology, mathematics, astronomy, and dialectic, and to oversee the laws. They are the city's 'anchor': because the laws cannot foresee every situation, a body of philosophically educated guardians must interpret and adjust them. The council is the closest the second-best city comes to the philosopher-rulers of the Republic.
Disputed Dialogues
Alcibiades I
Authenticity disputed. In late antiquity, this dialogue was often treated as the introduction to the Platonic curriculum (especially by Iamblichus). Socrates finally approaches the brilliant Alcibiades to warn him: without self-knowledge, his political ambitions will destroy both him and Athens.
InterlocutorsSocratesAlcibiades
103a–106c
Socrates' approach — why now?
Alcibiades, brilliant, beautiful, and well-connected, is about to address the Athenian Assembly for the first time, ready to dominate political life. Socrates approaches him for the first time after years of silent observation. He explains that his daimonic sign had until now forbidden conversation, but now permits it. Alcibiades is contemptuous — he believes he needs no advice. Socrates begins to break this confidence.
106c–119b
Alcibiades' assets and rivals
Alcibiades dreams of great power: ruling Athens, then Greece, then the world. Socrates congratulates him on the ambition and demands he see his actual rivals: not other Athenian politicians but the kings of Persia and Sparta. Both are educated from infancy in royalty, surrounded by counselors, trained in self-mastery and martial discipline. Alcibiades, by contrast, has had no comparable education. To surpass these rivals he must cultivate something they have failed to cultivate: genuine wisdom about good and evil.
129a–132c
What is self-knowledge? — the eye and the pupil
What does Alcibiades need to know? Himself — as the Delphic inscription commands. But what is the self? Not the body (which the self uses as an instrument) but the soul. To know oneself is to know one's soul. And how does the soul know itself? By looking at another soul — specifically at its rational, divine part, which functions as a mirror. (The eye sees itself by looking at the pupil of another eye; analogously, the soul knows itself in the soul of a wise interlocutor.) Self-knowledge requires philosophical companionship.
129e–130c
The soul is the true self
Since the self is the soul, taking care of yourself means taking care of your soul, not your body or your possessions. Bodybuilders care for the body, doctors care for the body, professional managers care for property — none of them is caring for the self. Care of the self requires philosophy: cultivation of the soul's virtues. Without this, all the body's beauty and all the wealth Alcibiades has count for nothing.
133c–135e
Politics without self-knowledge
The political conclusion. A ruler who lacks self-knowledge will pursue what he takes to be good but does not know to be good — and will inflict his confusion on the city. He will appear capable of guidance but actually be lost. Without becoming wise, Alcibiades will be a calamity for Athens and for himself. The dialogue ends with Alcibiades resolving to start practicing justice — though, as the audience knows, his historical course will involve sacrilege, treason, and disaster. The dialogue reads as a tragic might-have-been.
Hippias Major
Authenticity disputed. Socrates questions the pompous sophist Hippias about the nature of beauty (to kalon). Several definitions are proposed and refuted. Stylistically and philosophically close to early Plato.
InterlocutorsSocratesHippias
281a–286c
Meeting with Hippias — his worldly success
Hippias of Elis, the polymath sophist, arrives in Athens. He boasts of his diplomatic missions, his enormous earnings, and his all-around wisdom. Socrates warmly congratulates him while subtly mocking. He then says he was recently embarrassed by a sharp-tongued questioner (suspiciously like Socrates himself in elenctic mode) demanding to know what 'the beautiful' is. Could Hippias help him with an answer? Hippias is delighted to be asked something so easy.
287e–289d
First definition — beauty is a beautiful maiden
Hippias offers: a beautiful maiden is beautiful (kalon). Socrates makes the standard objection: this is an instance of beauty, not the Form by which all beautiful things are beautiful. He pushes further: a beautiful pot is beautiful, but not as beautiful as a beautiful maiden; a beautiful maiden is not beautiful compared to a goddess. Beauty is relative across kinds. We need to identify what beauty IS, not what is beautiful. Hippias does not see the point and grumbles.
289d–291d
Second definition — beauty is gold
Hippias tries again: gold makes everything beautiful when added. Socrates: but Pheidias did not make the eyes and face of his colossal Athena out of gold — he used ivory and stone, and people still considered the statue beautiful. So gold is not always appropriate. What makes things beautiful is the appropriate (prepon), not gold itself.
293e–295a
Third definition — beauty is the fitting (prepon)
Now Hippias proposes the beautiful is whatever is fitting (prepon) — appropriate to its purpose and context. But Socrates raises a subtle objection: the fitting MAKES things appear beautiful, but is appearance the same as being? If the fitting only makes things look beautiful but not actually be beautiful, then it is a different property. We're trying to identify true beauty, not its appearance.
295a–297d
Fourth definition — beauty is the useful
Hippias suggests the beautiful is the useful (chrēsimon), since whatever is useful for some good purpose is praiseworthy. But the useful is the powerful, the capable. And capability extends to capability for evil — a man powerful enough to do great wrong has a power, but is wrongdoing beautiful? Clearly not. So 'powerful for good' would be a refinement, but this brings us right back to needing a definition of the good — circular.
297e–304d
Fifth definition — beauty is the beneficial pleasant
Hippias proposes that the beautiful is the pleasure that comes through sight and hearing. Socrates raises a sharp problem: why these two senses specifically? Why not taste and touch, which also give pleasure? And if both visual pleasure and auditory pleasure are beautiful, the property they share — which is just being a certain kind of pleasure — is what beauty really is. But what kind of pleasure? Beneficial pleasure? Then it is the beneficial that makes things beautiful — and we are back to defining beauty as the cause of the good, which collapses into all the previous problems.
304e–304e
Aporia — the noble is difficult
No definition has survived examination. As Socrates departs to face his harsh imaginary interlocutor (himself), he and Hippias agree at least on the proverbial wisdom 'beautiful things are difficult' (chalepa ta kala). The dialogue's irony is that defining beauty has turned out to be vastly more difficult than Hippias supposed — and his confident polymathy has produced no genuine knowledge. The dialogue is a model exhibition of the elenchus applied to a key Form.
Hippias Minor
Authenticity disputed. Socrates argues the apparently scandalous thesis that it is better to do wrong voluntarily than involuntarily. The paradox connects to the Socratic doctrine that virtue is knowledge.
InterlocutorsSocratesHippiasEudicus
363a–369b
Opening — Achilles vs. Odysseus in Homer
Hippias has just delivered a public lecture on Homer praising Achilles as the most truthful (alēthēs) of the heroes and denigrating Odysseus as the most deceptive (polytropos, of many turns). Socrates raises a literary problem: in fact Achilles in the Iliad says one thing to Odysseus and another to Ajax shortly afterward — he is also inconsistent, and so himself a kind of liar. But the deeper question Socrates wants to pursue is whether the truthful person and the deceptive person are really different people at all.
369b–374d
The truthful and the false are the same man
Socrates argues that any expert who knows the truth about his subject is precisely the one capable of producing convincing falsehoods about it. Only the mathematician can deliberately give a wrong answer that looks right; the ignorant person gives wrong answers by accident. The willing liar in geometry IS the geometer. So the truthful man and the false man, in any domain, are the same person — the one with knowledge. The deceiver is a knower.
374d–376b
The voluntary wrongdoer is better
Socrates extends the principle. The runner who loses voluntarily (deliberately) is a better runner than the one who loses involuntarily — he had the option to win. Skilled and capable performers can choose to perform well or poorly; the unskilled cannot choose. Apply this to morals: the person who does wrong voluntarily has greater capacity than the one who does wrong involuntarily; the voluntary wrongdoer is therefore better in soul. Hippias is appalled but has no obvious refutation.
376b–376c
The paradox and the Socratic resolution
The conclusion seems morally outrageous, and Socrates himself confesses he cannot accept it — yet the argument seems valid. The deeper point reveals itself: the conclusion is absurd only on the assumption that anyone ever does wrong voluntarily. By the Socratic principle that virtue is knowledge, no one who genuinely knows the good chooses evil; all wrongdoing is from ignorance. So the voluntary wrongdoer — who would be 'better' on Socrates's argument — does not exist as a real type. The dialogue is a paradox-by-reductio supporting the central Socratic doctrine that no one errs willingly.
Menexenus
Socrates recites a funeral oration he claims to have learned from Aspasia. The dialogue is a puzzling parody or critique of Athenian funeral rhetoric, and Plato appears to signal this partly through deliberate anachronism — demonstrating how easily patriotic emotion can be manufactured.
InterlocutorsSocratesMenexenus
234a–236d
Frame — Socrates and Menexenus
Menexenus reports that the Council is selecting a speaker to deliver the public funeral oration for Athenians fallen in war (the famous epitaphios genre, exemplified by Pericles in Thucydides). Socrates says he could easily produce one himself — Aspasia of Miletus (Pericles's brilliant companion, often credited with composing his speeches) drafted one for him only yesterday, partly extempore, partly cobbled together from leftovers of the Pericles speech. Menexenus begs to hear it. The framing is loaded: Socrates is about to deliver a 'real' funeral oration learned from a woman who wasn't a citizen.
236d–249c
The oration itself
Socrates delivers the speech. It hits every conventional theme: the autochthony of the Athenians (born from their own soil, not immigrants); their virtuous constitution (a true aristocracy of merit, masquerading as democracy); their valor in the great wars — Marathon, Salamis, Plataea, the Persian Wars; their continued resistance against subsequent threats. The speech is technically virtuosic and includes a remarkable anachronism: it praises battles that occurred after Socrates's death (399 BCE), running through the Corinthian War of the 390s. Socrates is delivering a speech he could not have given.
249e–249e
The ironic critique
What is Plato doing? The speech reads as both genuinely effective (audiences are moved by such oratory) and as a parody. Some have read it as straight: Plato showing that even Socrates can deliver this genre. Most read it as ironic critique: the genre flatters the Athenian self-image with chauvinist mythology and anachronisms, and Socrates — the great enemy of flattering rhetoric in the Gorgias — produces a perfect specimen with deadpan delivery, exposing the cheap pleasure such rhetoric provides. The dialogue is short, stylistically odd, and one of the most puzzling pieces in the corpus.
Clitophon
The shortest dialogue in the corpus. Clitophon — a minor character from the Republic — confronts Socrates with a serious complaint: his exhortations to virtue are powerful, but he never actually delivers content. What is justice? What is its work? Socrates does not answer. Often paired with the Republic as a polemical preface.
InterlocutorsSocratesClitophon
406a–408b
Clitophon's praise of Socratic exhortation
Clitophon — a minor character from Republic Book I — confronts Socrates directly with a charge. He praises Socrates' protreptic exhortations to virtue: they are stirring, they make people care about justice, they shame the complacent. He has been to many of Socrates' speeches and they have moved him deeply. He acknowledges Socrates' rhetorical and motivational power.
408b–410a
The challenge — exhortation without content
But Clitophon then asks the natural follow-up: once you have exhorted me to pursue justice, what IS justice? What is its work? What does the just person produce? He went to Socrates' associates with this question and got only circular answers. Justice produces friends? But friends are a benefit; what is the specifically just product? Justice produces the just? But that is circular. The Socratic followers cannot articulate what the justice they so eagerly recommend actually consists in.
410a–410e
Socrates' silence
Clitophon concludes that he is left with stirring exhortation and no content — and that if Socrates cannot fill the gap, Clitophon must seek instruction elsewhere. The dialogue ends without Socrates responding. The shortest dialogue in the corpus is a polemical fragment whose authenticity is debated. Some scholars view it as a deliberate setup for the Republic, which immediately follows in the Thrasyllan ordering: Clitophon's challenge is exactly what the Republic answers, by elaborating justice in the soul and the city.
Epinomis
Likely not by Plato and often attributed to Philip of Opus as an appendix to the Laws. The Athenian Stranger answers a question raised in the Laws: what study leads to true wisdom? The answer: astronomy and the contemplation of the divine cosmic order.
InterlocutorsThe Athenian StrangerCleiniasMegillus
973a–979b
What is wisdom?
Picking up where the Laws left off, the Athenian Stranger, Cleinias, and Megillus consider what study leads to true wisdom. The Stranger surveys all human arts and sciences. None of the practical arts (agriculture, craft, building) produces wisdom in the highest sense; none of the productive arts; not hunting, not interpreting (rhapsody), not divination, not generalship. All these are partial. We need something universal.
976d–978b
Number as the gift of God
The greatest gift the gods gave humans is number. Without number, no genuine reasoning is possible — no calculation of magnitudes, no music, no astronomy, no architecture. Number is what reveals proportion and harmony. The very capacity to count distinguishes humans from beasts. Without it, virtue itself is impossible, since virtue requires measure (a doctrine carried forward from the Philebus and the Statesman).
978c–990a
Astronomy as the highest study
The highest application of number is astronomy. The motions of the planets are perfectly orderly and uniform — eight motions in total (the fixed stars, sun, moon, and five planets), each in regular paths. Their order is divine. The contemplation of these motions assimilates the human soul to the cosmic intelligence — a doctrine of homoiōsis theō (becoming like god) through astronomy. This is true wisdom: not earthly cleverness but cosmic understanding.
984d–992e
Theology and the visible gods
The heavenly bodies are not just symbols of gods — they ARE gods, visible divine beings. The wise person recognizes this and orients their life accordingly. The Nocturnal Council from the Laws should pursue astronomy above all other studies, since it gives them direct knowledge of the cosmic order they are tasked with reflecting in the city. Almost certainly written by Plato's secretary Philip of Opus, the Epinomis is a coda that pushes Plato's late metaphysics in an explicitly astronomical-theological direction.
Theages
Likely spurious (possibly Academic-era). Demodocus brings his son Theages to Socrates because the young man wants to be 'wise.' Notable for an extended discussion of Socrates' divine sign (daimonion) and its workings.
InterlocutorsSocratesTheagesDemodocus
121a–123b
What does Theages want?
Demodocus brings his son Theages to Socrates for instruction. Theages wants to become wise. Socrates probes: wise about what? Wise to rule horses requires horse-knowledge; wise to rule humans requires human-knowledge. Theages clarifies: he wants the wisdom that produces tyrants — the practical political wisdom that gives a man power. Socrates ironically commends the ambition and asks why he hasn't gone to a sophist.
128d–130e
The daimon's work
Theages reveals he wants to learn from Socrates specifically. Socrates demurs: he has no teaching to give. But he describes his daimonic sign — the inner voice that warns him against certain actions. He recounts cases where his sign warned associates against military or political actions; those who heeded the warning prospered, those who ignored it perished. The daimon assists 'those who are akin' to Socrates — meaning, suitable philosophical companions. Whether it will assist Theages is uncertain.
130e–131a
Conclusion — try association, not teaching
Socrates concludes that he cannot teach Theages anything but that they can spend time together. If the daimonion permits the association, Theages may become wise; if not, no force can make it work. The dialogue's value is mainly in its detailed treatment of the daimonion — Socrates's famous personal sign — though it is almost certainly post-Platonic, perhaps from the 4th- or 3rd-century Academy.
Minos
Likely spurious (possibly Academic-era), often paired with the Laws as a thematic introduction. Socrates and an anonymous companion discuss what law is. The dialogue includes a digression on the Cretan king Minos, treating him not as the harsh judge of myth but as a model lawgiver.
InterlocutorsSocratesAnonymous companion
313a–315b
What is law?
Socrates and an anonymous companion ask: what is law? The companion proposes: law is what the city has decreed. Socrates objects: cities decree both wise and foolish, just and unjust ordinances. If law is what the city decrees, then unjust law is also law — but law aims at justice; an unjust 'law' is a deformed thing, not a genuine law. So law is essentially what is just, not merely what is enacted.
315b–316a
Variation in laws
The companion notes that different cities and times have different laws — Persians, Greeks, Carthaginians legislate differently on the same matters. So how can law be objective? Socrates: in fact, what is genuinely good and right is the same everywhere; cities differ on what they think is good, not on what genuinely is. Law in its truest sense is the discovery (heuresis tou ontos) of what is — what is genuinely good for human life.
318c–321d
The model lawgiver Minos
Socrates digresses on Minos, the Cretan king, who in Athenian tragedy is a harsh tyrant. The Cretan tradition (and Homer) presents him otherwise: Minos went up Mount Ida every nine years to be educated by his father Zeus, and brought back laws that preserved Crete for centuries. The Athenian image of Minos is a slander grown out of Athenian tragedians angry at Theseus's wars. Genuine lawgivers — Minos, Lycurgus, the legendary lawgivers — were philosophical kings. The dialogue is short and most scholars consider it spurious, possibly written as a thematic introduction to the Laws.
Hipparchus
Likely spurious (possibly Academic-era). An anonymous interlocutor and Socrates discuss what 'love of gain' (philokerdes) really means. Contains a digression on the Pisistratid tyrant Hipparchus.
InterlocutorsSocratesAnonymous companion
225a–226d
What is love of gain?
An anonymous companion and Socrates discuss what 'love of gain' (to philokerdes) means. The companion says it is the desire for profit (kerdos), including from worthless or harmful sources. Socrates raises a problem: if profit is always something good, no one can love profit from a worthless source — they would not be desiring profit but loss. By the Socratic principle that all desire aims at the good, no one really desires bad things even if they appear good.
228b–229c
The digression on Hipparchus
Mid-dialogue, Socrates digresses into history. The Athenian tyrant Hipparchus, son of Pisistratus, is here praised (against the standard Athenian view) as a wise ruler who patronized poetry, brought Homeric rhapsodes to the Panathenaea, and set up stone Herms (roadside pillars bearing the head of Hermes) along Athenian roads inscribed with brief moral sayings — a kind of public moral education. The digression is striking because it praises a tyrant whom Athens officially celebrated for being assassinated.
231a–232c
Aporia
After the digression, the conversation circles without resolution. If gain is by definition good, there can be no love of bad gain. But common usage describes greedy people as pursuing both honest and dishonest profit. The disagreement turns on whether 'gain' is a moral term or a neutral one. The dialogue ends without settling the question. It is short, philosophically thin, and almost certainly spurious.
Rival Lovers
Also called 'Lovers' or 'Anterastae.' Likely spurious (possibly Academic-era). In a wrestling school, two boys argue — one a generalist, one an athlete. Socrates asks: what is philosophy and what is it good for?
InterlocutorsSocratesAnonymous boys
132a–134e
The two rival lovers
In a wrestling school, Socrates encounters two young men disputing — one a self-styled philosopher who scattered learning across many subjects, the other a gymnast (a body-trainer) — both rivals for the affection of another beautiful boy. Socrates engages them in a discussion of which is the better suitor: the cultivator of the mind, or the cultivator of the body.
134e–137a
What is philosophy?
The 'philosopher' boy claims philosophy means having a little knowledge of every subject — like a polymath who is half-learned in geometry, music, astronomy, etc. Socrates dismantles this: in any specific subject, the dilettante is inferior to the actual expert. So philosophy as a smattering of all subjects is just the second-rate version of every craft. It cannot be defined this way.
137a–139a
Philosophy as the art of self-rule
Socrates gestures toward an alternative definition: philosophy is the art of self-rule and rule of others — the knowledge of justice, of how human affairs ought to be conducted. But the argument is undeveloped. The dialogue is short and inconclusive; it lacks the depth of the genuine early dialogues. Almost universally considered spurious, it preserves the genre but not the substance.
Alcibiades II
Widely regarded as spurious (likely from the 3rd-century BCE Academy). Alcibiades is going to pray. Socrates warns him: praying for the wrong things, when you do not know what is truly good, can be dangerous.
InterlocutorsSocratesAlcibiades
138a–140c
The danger of prayer
Alcibiades is on his way to offer prayers and sacrifices to a god. Socrates intercepts him with a warning: praying without wisdom is dangerous. Many have asked for and received what they thought were goods only to be ruined by them. Oedipus prayed for vengeance on his sons and brought disaster. Tyrants pray for power and become objects of their own subjects' assassination plots. Even those who pray for children, wealth, or victory can be destroyed by exactly what they receive.
143a–144b
The poet's wisdom
Socrates appeals to a saying he attributes to a Spartan poet: 'King Zeus, give what is good to us, whether we pray for it or not; but what is evil, ward it off, even when we pray for it.' Wise prayer is general, not specific: ask for the good without specifying it, since you do not know what the good is. The same logic applies to all action: only knowledge of good and evil makes any action beneficial.
150b–151c
Conclusion — wisdom must precede prayer
True piety requires the knowledge of what is genuinely good — and Alcibiades, like most people, lacks it. Until he acquires it, he should suspend specific prayers and only honor the gods generally. Even the Athenians collectively were once advised by the priestess at Delphi to maintain quiet for a long time before resuming sacrifices. The dialogue ends with Alcibiades dedicating his garland to Socrates as a sign of pious deference. The whole work is short, somewhat thin, and almost certainly written by a later Academic — but it preserves an important Socratic theme: wisdom is the precondition of even religious practice.
Letters
Letters (Epistles)
Thirteen letters attributed to Plato. Scholarly confidence varies: Letter VII is often treated as likely authentic, Letter VIII remains contested, and many others are disputed or widely judged spurious. They are the closest thing we have to Plato writing in his own voice. The Seventh Letter is the major autobiographical and philosophical document.
InterlocutorsPlato
309a–310b
Letter I✗ Spurious
A bitter, brief letter from Plato to Dionysius II of Syracuse, complaining of being dismissed without honor after years of philosophical service. Almost universally considered spurious — its tone is wrong for Plato (querulous, transactional), and the historical situation it depicts doesn't match what we know from elsewhere.
310b–315a
Letters II–IV? Disputed
Letters II, III, and IV concern Sicilian politics in various phases. Letter II (to Dionysius II) is famous for declaring that 'there is no treatise by Plato, nor will there ever be' — a statement either authentic and important for Platonic interpretation, or a clever forgery. Letter III defends Plato against political accusations from Dionysius's circle. Letter IV (to Dion) urges him to combine military success with philosophic moderation. Authenticity ranges from possible to unlikely depending on the scholar.
321a–321d
Letter V? Disputed
Addressed to Perdiccas, king of Macedon, urging him to take political advice from a young man Plato has trained. If genuine, it shows the Academy's reach into northern Greek courts. Most scholars consider it spurious.
322b–323b
Letter VI? Disputed
Written to Hermias, ruler of the small Asian state of Atarneus, and to two philosophers (Erastus and Coriscus) at his court. The letter recommends Plato's mature philosophical approach to moral and political life and proposes the three swear an oath of friendship. Authenticity is doubtful but not impossible.
323d–352a
Letter VII — the major document~ Likely authentic
The most important letter, widely (though not universally) accepted as authentic and the closest Plato ever came to autobiography. Addressed to Dion's followers in Syracuse after Dion's assassination, it has four major sections. (1) Autobiographical: Plato describes how, as a young man, he expected to enter politics — but the rule of the Thirty Tyrants (which involved his relatives Critias and Charmides) horrified him, and the restored democracy then executed Socrates. He concluded that no city was justly governed and that the human race will not be free of evils until true lovers of wisdom come to hold political power, or the holders of political power become true lovers of wisdom. (2) The famous Philosophical Excursus: the deepest truths cannot be conveyed in writing or in casual exposition but emerge only after long shared work — 'like a flame kindled by a leaping spark.' Anyone who claims to have written down Plato's deepest doctrines is therefore lying. (3) The five-stage epistemology: knowledge of any object proceeds through name, definition, image (perceptual instance), knowledge in the soul, and finally the thing itself (or the Form) — and only the last is the proper object of philosophy. (4) Detailed account of Plato's three trips to Sicily, his complicated relationship with Dionysius I and II, his attempts to educate Dionysius II philosophically, the conspiracies, his rescue, and the eventual disasters that culminated in Dion's death.
352a–358a
Letter VIII~ Likely authentic
Following on from the Seventh, this letter offers practical political counsel to Dion's surviving followers. It recommends a constitutional monarchy under law: three kings (one descended from Dion's lineage, one from Dionysius's, one from a Spartan family) with strictly defined powers, balanced by a Council and laws. The proposal aims at reconciling factions in Syracuse without further bloodshed. Generally considered authentic, it shows Plato's late-life political pragmatism — closer to the constitutional thinking of the Laws than to the philosopher-king ideal of the Republic.
357d–363e
Letters IX–XIII✗ Spurious
The remaining letters are short and varied. Letter IX (to Archytas of Tarentum) discusses the obligation to serve one's city. Letter X is brief and trivial. Letter XI declines an invitation. Letter XII (to Archytas, on Pythagorean writings) is suspect. Letter XIII (purportedly to Dionysius II) contains domestic and financial details often regarded as forged to look authentic. Most scholars consider IX–XIII spurious or doubtful, though pieces of historical information may still be drawn from them.