the cave in Plato's Republic

Plato’s Republic—a short summary

Plato’s Republic, written in about 380BCE, consists of a dialogue between Socrates and 5 other people.  In the book Socrates acts as the voice for Plato’s ideas on how a just city, or a society as we would say, needs to be organized.

The following is a summary of  

  • its main ideas
  • its definition of justice
  • soul and city
  • the role of education
  • the allegory of the cave
  • why he designed it like this?
  • some critiques that can be made of it

We are using the very readable translation by AD Lindsay from 1935. You can find it here.

Main ideas of Plato’s Republic

The government of Athens has condemned to death Plato’s teacher, Socrates, for his teaching and his philosophical questioning in the city among some of its young people. It is claimed that his followers have lost respect for the traditions and institutions of the city. Plato sees this as a massive injustice. So, he sets out to design a just city, one that will not suffer corruption among its leaders, and one that would not condemn critical thinkers to death.

His conclusion is that that for a society to have just leaders, those leaders need to be educated so that they understand truth, goodness, and beauty. This means they will learn the truth of serving the needs of others before their own, and putting their own personal desires to one side so that they can serve society’s needs as a whole. It’s a remarkable idea. Leaders who find true happiness and meaning not in having all the things they might desire for themselves, but in making sure that everyone else lives the best possible lives that they can. (Imagine!)

Introduction to justice in Plato’s Republic

In Book 1 he challenges us to think about whether we really want justice at all, or whether in fact we only pay lip service to the idea? What if the person who cheats their way through life has a better time of it than people who try to do the right thing? Who would then bother to try to act justly in their lives?  He tests this in Book 2 with a tale of invisibility. Suppose you had a magic ring on your finger that could make you invisible. Even if you believed in acting justly, given that you could never be caught or arrested, what would stop you using the ring to your own advantage, perhaps by stealing whatever you wanted? Perhaps all of us only act within the law because we fear punishment, not because we actually believe it is the right way to live. A ring of invisibility would test that.

Someone also suggests to him a kind of sociological point that perhaps justice is really only whatever any particular society says it is. And since the strong always run a society, justice is whatever the people in power tell everyone else it is, and, not coincidentally, they will define it in whatever way is to their own advantage.

So, our first challenge from the Republic. Do you really believe in justice or do you just pretend to? What if Glaucon is right. He says, it is not in our nature

‘to abide in justice and have the strength to abstain from theft, and to keep our hands from the goods of others, when it would be in our power to steal anything we wished from the very market­place with impunity … in short, to walk among men as a god’ (360c).

Defining justice in Plato’s Republic

Book 2 now asks a fundamental sociological and political question. If you are trying to organize a just society, then two questions might be more important than all the others: who does which jobs, and who gets most and least reward for their work? Sort this out justly and you might stand a chance of a fair society. Sort this out badly, and you recreate an unequal world.

Plato has an answer that does not look immediately helpful. In thinking about how to form a society he says this.

‘The origin of a city [is] due to the fact that no one of us is sufficient for himself, but each is in need of many things… Then men, being in want of many things, gather into one settlement … to satisfy their diverse needs, and to this common settlement we give the name of city… But the first and greatest of our needs is the provision of food to support existence and life? The second the provision of a dwelling-place, and the third of clothing, and so on?’ Come, then,[ ] how will our city be able to supply a sufficiency of all those things? Will it not be by having one man a farmer, another a builder, and a third a weaver? Shall we add a shoemaker, and perhaps another provider of bodily needs? (369)

This ‘division of labour’ is known as the idea of one-person one-trade. His justification is simple. If you want the best possible society, a just city, then you have to have every job done by the people who are best able to do them. The best farmer, the best brain surgeon, the best cleaner. Everyone has a natural inclination to be good at something. Find it and let them contribute this natural talent for the good of society.

He is not defining justice as some kind of co-operative collective life where everyone works for everyone else and has somehow left behind self-interest! The way people distribute the products of their labour is not by sharing, but by owning things through the process familiar to us—buying and selling by means of money.

Then, he says, it is likely that these people will want more luxuries, perhaps spices for food, or comfortable couches to lie on, or perfumes to sweeten the air.  More desires need more production. And so, the city grows in size. When it is at full capacity but still needs to grow, it will look to its neighbours, and perhaps take their land by force. Here is war. And to win a war you need the best soldiers. So, the city will need to find those people who are strongest and bravest by nature, and their job will be to guard the city better than anyone else could. Most important, if the city is to be just, this army cannot turn against its own people. The soldiers must learn friend from foe, so as not to use their power against their own city, but only against its enemies.  This will require education. More on that in a moment.

In sum, so far then, it seems that for Plato a definition of justice is where everyone in a society does what they are naturally best at, and when everyone can buy and sell the results of their skills.

Soul and city in Plato’s Republic

Let’s move this on a bit. Plato worries that people don’t always feel very attached to their society. In our modern language we might say people feel alienated from society, or don’t feel patriotic or dutiful towards their society or to anyone else in it. He now suggests something that might prevent this ever happening. It is his theory of the soul and the city. To understand how his Republic works, and why he thinks it is a just society, you have to understand his theory of the soul and the city. It’s not a difficult idea.

The soul, he says, is made of three parts: desire, spiritedness, and reason.

The city, he says, is also made of three parts: Traders, who buy and sell, soldiers who guard and fight, and the most rational people, philosophers, who will make the best rulers. He knew that the idea that philosophers should govern society would sound odd. No doubt it still does so today.

The link between the soul and the city now becomes obvious. If your soul is predominantly characterized by desire, then you will be best at buying and selling. If your soul is predominantly characterized by courage and spiritedness, you will be the best guardian. And if your soul is predominantly characterized by reason then you will be a philosopher and a make the wisest ruler.  Now we can put his first two big ideas together. If everyone does the work that most suits their own soul, no occupation can be unjust. People will be living their own truths. It would be unjust to make someone do work that opposed their own soul. The supposition is that people will be happiest doing that which comes most naturally to them. But more than that, each soul finds its expression, its home, its sense of belonging, in one part of the city. The soul and the city are one in each citizen. There would be no separation of individual and society, or no alienation as we might say,

when each class, money-makers, auxiliaries, and guardians, attends to what belongs to it, each doing its own work in the city, [and this] will be justice, and will make the city just (434)

Now we have come close to Plato’s idea of why his Republic is just.

The role of education in Plato’s Republic

How do you find out which souls are best suited for each job in the city? The answer is to test the young to see what their natural abilities and characteristics are. Then select from within them who best fits in each of the three classes of people. He doesn’t spend time telling us much about the education of young producers and traders. Most of the rest of the book tells us about the education of those who are to be guardians and philosopher-rulers.

Education will need to instill self-discipline in these students and not let desires get out of control. The rich, he observes, probably lack a meaningful life, so we should learn from this not to treat wealth as an end in itself. That should help to reign in the desire for luxuries and avoid unnecessary wars. Nothing in excess might be the key thing that the city will teach its people.

Souls, like bodies, will be made beautiful, in pursuit of truth and beauty, not ugly in pursuit of wealth and status. There will be music for the soul and gymnastics for the body. More controversially, a just society will need to censor some literature so that young souls do not have evil ideas imprinted upon them at an early age—something like the modern idea that films and video games and some stuff on social media should have age restrictions. And he says that some music will have to be banned if it arouses uncontrollable passions. Lying will be banned for all, save those who might need to lie for the benefit of society as whole (which today might be something like hiding or lying to protect official secrets, for example).

The key criterion for deciding who will be philosopher-rulers will be to select those who in their youth, display public-spiritedness or putting others before themselves, be they men or women. They will then be separated off and given a different kind of education. They will live in common, eat together, share all possessions, have equal access to stores of goods, have no houses or property of their own; neither will they have families or children of their own. The reason for all this is that to learn to be the best possible rulers they must never be tempted to put personal interest above public interest. Thus they must have no personal interests, and especially not husbands or wives or children of their own.

There is one further controversy to mention here. In order to make sure that the society has the best people running it, Plato supports a kind of eugenics or selective breeding programme. He seeks to make sure that the most virtuous people will be able to procreate with each other as often as possible. In addition, euthanasia will be practiced out of public sight on any babies born that are not ‘normal’.   

Summarizing the allegory of the cave—defining philosophical education

There is a cave (possibly the cave of Vari at Mount Hymettus). At the back of the cave there are people who have been chained to chairs all their lives unable to move or turn round. They continually stare at the back wall, watching shadows pass in front of them. They think this is reality, for it is all that they have ever known. The shadows are of objects carried by people behind the backs of the prisoners, shielded by a wall and cast by a fire. The prisoners know none of this.

Plato then suggests that if one of the prisoners was released and allowed to turn round several things would happen. First their eyes would be blinded by the light of the fire. They would not be able to see clearly. When they grew accustomed to the light, they would see that their loves had been an illusion. Truth lay behind them, not on the back wall of the cave. This would make them reassess everything they thought they knew. 

Now suppose that this prisoner is dragged up a steep path to the entrance to the cave, and goes outside for the first time. Again they would be blinded by light, this time by sunlight, and would not be able to see any of the objects in this upper world clearly. When their eyes adjusted they would see shadows, reflections, and objects, and finally the sky and the stars and planets. Only when their eyes were fully adjusted to the light of the upper world would they be able to see the sunlight and finally the sun itself. Soon they would also be able to see how the sun commands the seasons and the yearly cycle and is responsible for all that can be known in the upper world. They would come to understand the sun as the condition of the possibility of everything. Now, for Plato, they are enlightened about the true causes of everything in the universe. Their education in the upper world being complete, they return to the cave and sit once more in the seats to which they had been bound. Their journey most likely will not be believed by the remaining prisoners. As such, the new philosophers have to become their rulers, since they are the wisest in the city. Remember, they have already been chosen because they naturally put others before themselves. They have no wealth or families of their won, and thus can rule in the best interests of everyone, and not be corrupt in pursuit of power for self-interest. These leaders are what we might call public servants.

Why did Plato design his Republic like this?

The cave explains pretty much everything about why Plato sets up the Republic as he does. Remember that he had lived through the so-called Golden Age of Athens, but also war and dictatorship under the Thirty Tyrants, including of some Plato’s own relatives. He saw democracy being controlled by clever speakers who could sway public opinion one way or another, at a time when democratic politicians were not trusted all that much on a range of matters. They were seen as lacking expertise, and part of Plato’s desire for philosopher rulers was a response to this perceived rule by the ignorant. He also saw the injustice of his teacher, Socrates, being given the death penalty who had himself criticized some democratic instructions, and of course many of the so-called wise individuals of the time. Integrity and honesty of character were not needed for success in the city. These would have been some of the motivations behind the proposals in the Republic. Our own time is no stranger to political corruption, rule by self-interest, and recently a distrust of experts. What Plato perhaps wanted to create was a society where wisdom, virtuous character, self-sacrifice, and lack of self-interest were the criteria for being trusted with political power.

Critiques of Plato’s Republic

Is this a society of wise and benevolent rulers working for the happiness of all and not just for some? Or is this a society run by an elite who think they know better than everyone else.

A critical view from today might be that his Republic, his ideal city, is still an unequal society because some will be more successful and more powerful than others. What is to stop people exploiting others for their own gain? Perhaps his proposals don’t sound very fair, or perhaps we might say, he does not seem to have thought about equality very much? A special class of people are to have a special kind of education so that can be given all the political power in the city. Others will be made either to defend the city in the military or to spend their lives producing and selling the basic things that the city needs to survive. Isn’t this what we would call a class-based society or a hierarchical society? A society where different classes live and work completely separated from the rulers. A society in which the rulers breed among themselves, and in which anyone born too different will be disposed of at birth? In the mid 20th century Karl Popper wrote about his dislike of Plato with a passion. He argued that Plato wanted a society so that he and his like—other philosophers—could become ‘totalitarian demi-god[s]’ (Popper, 132). Popper says,

‘Plato’s best state is based on the most rigid class distinctions. It is a caste state … The workers, tradesmen etc, do not interest him at all, they are only human cattle whose sole function is to provide for the material needs of the ruling class. (Popper, 1962, pp.46-47)

On the other hand, someone like Robin Barrow has argued that

‘There is absolutely no evidence to support the contention that the Republic is a class society in which advantages or anything else are distributed by reference to the criteria of birth or family connection; nor wealth anywhere referred to as a criterion of distribution. The fundamental criterion is aptitude, which involves capability and interest, and such things as material possessions are distributed to the largest group rather than the rulers precisely on the assumption that they will need and want them’ (Barrow, 1975, p. 150).

The best way to form your own opinion is to read the book for yourself. It is not unusual to feel daunted at the thought of reading a book like Plato’s Republic, especially if you try to do so on your own and without people to talk it through with. If you would like to try to read it, with help and support and from an experienced tutor, in the company of others who also want to read it, then consider signing up for the Think Learning course here.

And if you want to read a modern version of The Republic written by the tutor of this Think Learning course (Nigel Tubbs) then try Socrates On Trial (Bloomsbury 2021).

Nigel Tubbs


Barrow , R (1975) Plato, Utilitarianism and Education (London: RKP)

Plato, (1954) The Republic, translated AD Lindsay, London, Everyman Dent.

Popper, K, (1962) The Open Society and its Enemies, Vol I (London: Routledge)