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Plato’s Allegory of the Cave Explained

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Plato's Cave

Plato's Cave

The Dialogues of Plato

The works of the fourth century BC Greek philosopher Plato have survived for over 2,500 years and are still read and studied today. Of his thirty-six books or dialogues, nearly all are written in the form of a conversation (dialogue) between the philosopher Socrates and others. Socrates roamed the streets of Athens trying to enlighten the thoughts of those around him through conversation. In many of Plato’s dialogues, Socrates is the main speaker. Since Socrates was put to death when Plato was a young man, most scholars believe the voice of Socrates in Plato’s works is simply a literary device used by Plato. No one is sure where the teachings of Socrates end and those of Plato begin.

Plato’s dialogues cover a wide range of philosophical topics, ranging from ethics, politics, and mathematics, to the nature of the world and human cognition. Plato’s longest and most famous work is The Republic, which was probably written around 380 BC. In The Republic, Socrates converses on a variety of topics with various Athenians and foreigners visiting Athens. Central themes of the book are the meaning of justice and whether a just person is happier than an unjust person. Through the voice of Socrates, Plato lays out a series of hypothetical cities, culminating in the utopian city-state ruled by a philosopher-king.

One of the most discussed sections of The Republic is the Allegory of the Cave, where Plato tells a story of prisoners trapped in a cave and their assent into the sunlight (true knowledge). It is a classic allegory that has stirred discussions within countless generations of students and scholars and will likely do so for many generations to come.

Illustration of Plato’s Cave

Illustration of Plato’s Cave

Plato’s Description of the Cave in the “Republic”

In book seven of the ten books of The Republic (sections 514a to 520a), Plato presents a dialogue between his old mentor Socrates and Plato’s older brother Glaucon. Preceding the cave allegory in The Republic are analogies of the Sun and the Divided Line, which set some of the philosophical groundwork for the allegory.

Plato, again through the voice of Socrates, makes it clear, from the onset of the story about the prisoners in the cave, that education is at the heart of the story. He tells Glaucon:

“Next, I said, compare the effect of education and the lack of it upon our human nature to a situation like this: imagine men to be living in an underground cave-like dwelling place, which has a way up to the light along its whole width, but the entrance is a long way up. The men have been there from childhood, with their neck and legs in fetters, so that they remain in the same place and can only see ahead of them, as their bonds prevent them turning their heads. Light is provided by a fire burning some way behind and above them. Between the fire and the prisoners, some way behind them and on a higher ground, there is a path across the cave and along this a low wall has been built, like the screen at a puppet show in front of the performers who show their puppets about it.” Glaucon responds, “I see it.”

Socrates continues to explain the scene to his companion Glaucon, telling him there are men carrying, along a wall behind the prisoners, “all kinds of artifacts, statues of men, reproductions of other animals in stone or wood fashioned in all sorts of ways.” Some of the carriers are talking while they parade back and forth behind the wall, while others are silent. Behind the statue carriers is a roaring fire that casts the shadows of the statues of the men and animals on the wall of the cave for the prisoners to see. The prisoners only see the shadows of the figures on the wall and hear only the voices of the carriers—this was the prisoner’s reality.

Socrates and Glaucon speculate on how the prisoners spend their days in fetters watching the shadows on the wall. Socrates states, “If they could converse with one another, do you not think that they would consider these shadows to be the real things?” Glaucon answers, “Necessarily.” Socrates and Glaucon both agree that the prisoners must believe that the truth to be “nothing else than the shadows of the artifacts.”

The chained prisoners see images on the wall.

The chained prisoners see images on the wall.

A Prisoner Is Freed

Socrates now considers if one of the men were freed: “Whenever one of them was freed, had to stand up suddenly, turn his head, walk, and look up toward the light, doing all that would give him pain, the flash of the fire would make it impossible for him to see the objects of which he had earlier seen the shadows.” As the freed prisoner gazes into the fire, Socrates conjectures that his eyes would hurt as he was not accustomed to so much light, and that he would turn away. The philosopher poses the question, “Do you not think he would be at a loss and believe that the things which he saw earlier were truer than the things now pointed out to him?” Glaucon agrees.

The Prisoner Reaches the Entrance of the Cave

Now the freed prisoner is dragged up the rough and steep path to the mouth of the cave and the sunlight. Socrates relates, “When he came into the light, with the sunlight filling his eyes, he would not be able to see a single one of the things which are now said to be true.” As his eyes adjusted to the light, he would at first see shadows, then reflections in a pool of water, then the things around him. After his eyes became fully adjusted to the bright light of day, he could see the sky and the sun. Socrates continues, “Then, at last, he would be able to see the sun, not images of it in water or in some alien place, but the sun itself in its own place, and be able to contemplate it.” Glaucon replies, “That must be so.”

When the prisoner is out in the light and this new world, he begins to understand the world around him and that the sun provides the seasons of the year. He thinks back to the cave and “…of the wisdom there and of his fellow prisoners, would he not reckon himself happy for the change, and pity them?” In the cave, the men occupy their time by observing the shadows on the wall and prophesying the future as to which shadow would come next. The freed prisoner realizes he would rather be free in the light than a captive amongst the prisoners in the cave.

The Prisoner Returns to the Cave

Next Socrates discusses with Glaucon what would happen if the prisoner returned to the cave to see his former fellow prisoners. As the man enters the darkened cave, it takes time for his eyes to adapt to the darkness. Socrates paints the scene when the man encounters his fellow prisoners: “Would it not be said that he had returned from his upward journey with his eyesight spoiled, and that it was not worthwhile even to attempt to travel upward? As for the man who tried to free them and lead them upward, if they could somehow lay their hands on him and kill him, they would do so.” To the men still in fetters, their freed companion appears to be tortured to the point of having compromised eyesight, so much so that he cannot clearly make out the shadows on the wall.

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Socrates then tries to bring out the essence of the story to his companion: “If you interpret the upward journey and the contemplation of things above as the upward journey of the soul to the intelligible realm, you will grasp what I surmise since you were keen to hear it…that in the intelligible world the Form of the Good is the last to be seen, and with difficulty; when seen it must be reckoned to be for all the cause of all that is right and beautiful,…”

Socrates starts to wrap up his story by explaining to Glaucon how the cave and the prisoners relate to education. Socrates: “We must then, I said, if these things are true, think something like this about them, namely that education is not what some declare it to be; they say that knowledge is not present in the soul and that they put it in, like putting sight into blind eyes.” Glaucon agrees, “They surely say that.” Socrates continues, “Education then is the art of doing this very thing, this turning around, the knowledge of how the soul can most easily and most effectively be turned around; it is not the art of putting the capacity of sight into the soul; the soul possesses that already but it is not turned the right way or looking where it should.”

Socrates sums up the effects of a proper education of a philosopher-king and comments on how his method of education would be superior to what is currently happening in Athens: “It is then our task as founders, I said, to compel the best natures to reach the study which we have previously said to be the most important, to see the Good and to follow that upward journey. When they have accomplished their journey and seen it sufficiently, we must not allow them to do what they are allowed to do today.”

The Dutch artist Jan Saenredam’s interpretation of the allegory of Plato’s Cave, circa 1604.

The Dutch artist Jan Saenredam’s interpretation of the allegory of Plato’s Cave, circa 1604.

Earlier in The Republic, the character of Socrates discuses two analogies, the Sun (507b to 509c) and the Divided Line (509d to 511e), which are linked to the Allegory of the Cave. In the dialogue between Socrates and Glaucon, the former reveals the sun to be the “child of goodness.” He further relates that the sun illuminates, bestowing the ability to see and be seen by the eye. Plato writes, “What the Good itself is in the world of thought in relation to the intelligence and things known, the sun is the visible world, in relation to sight and things seen.” Plato tells his readers that the Good (the sun) provides the foundation on which all truth rests. The image of the sun gives insight into the true meaning of the Good, allowing our minds to see true reality.

The analogy of the Divided Line breaks down the ideas of moving from the visible world of understanding (Forms). The dialogue is between Glaucon and Socrates, in which Socrates tells his companion how the world is divided:

“…There are those two, one reigning over the intelligible kind and realm, the other over the visible…So you have two kinds, the visible and the intelligible…It is like a line divided into two unequal parts, and then divide each section in the same ratio, that is, the section of the visible and that of the intelligible. You will then have sections related to each other in proportion to their clarity and obscurity. The first section of the visible consists of images—and by images I mean shadows in the first instance, then the reflections in water and all those on close-packed, smooth, and bright materials, and all that sort of thing, if you understand me.” Glaucon responds, “I understand.”

Illustration of the analogy of the Divided Line.

Illustration of the analogy of the Divided Line.

In the figure, B is the highest point in the scale of reality, which is analogous to the sunlit world or, in the language of the Forms, “the Good.” A represents the lowest level of existence, like the prisoners in the cave, where images or reflections of the world are only seen. The region depicted from D to E represents the transition from the lower level of images, or the freed prisoners climbing toward the light of the sun into the realm of true understanding.

Plato’s Forms

Throughout the centuries, Plato’s Allegory of the Cave has been interpreted in countless ways. As in many of Plato’s writings, he uses one of his central themes, the theory of Forms or Ideas, in the Allegory of the Cave. To Plato, the world we perceive with our senses is somehow defective and filled with error. He believes there is a more perfect realm populated with entities called “Forms” or “Ideas” that are eternal and changeless and represent in some sense a paradigm of the structure and character of the physical world perceived by human senses. It is with this idea of the Forms in mind that one must understand the Allegory of the Cave.

The six types of triangles are elements of the Form of Triangularity.

The six types of triangles are elements of the Form of Triangularity.

Meaning of the Allegory of the Cave

The Allegory of the Cave presents the concept that the mental state of most ordinary people is like that of the prisoners chained in the cave watching shadows cast upon the cave wall. The modern equivalent would be people who only see what they are shown in their choice of media. The media executives, advertisers, politicians, religious leaders, etc., are like the captors in the cave; they control what the prisoners (citizens) think, see, and read.

When one of the prisoners is freed from their chains—analogous to seeking knowledge and questioning the world around them—he (or she) discovers that what he thought was real was simply shadows or images of objects. As he begins the arduous journey out of the cave, he sees the fire and the captors and begins to understand reality better. The ascent out of the cave is symbolic of recovering the knowledge of the Forms, which Plato believes is already inside of us all. In the modern sense, this is like a person who questions the information they are given and seeks to gain a deeper understanding of their reality.

When the freed prisoner reaches the mouth of the cave to see the sun—“child of the Good”—he begins to perceive the world through Forms and Ideas, or through reason rather than just through a perception of the world limited to five senses. Socrates likens the freed prisoner to a philosopher who strives to understand and perceive the higher levels of reality. The sun represents the Form of the Good, the highest level of all forms. In modern parlance, those who seek the sun and understanding are looking for the interrelationships of events, rather than accepting what they are presented at face value.

The prisoners who choose to remain in the cave represent individuals who don’t seek a higher understanding of reality and are content with their lives. They have no desire for change and accept the dogma presented to them. According to Plato, those who remain are willing to kill anyone who tries to remove them from the cave.

Plato uses the analogy of the Sun, which represents the form of the Good; the analogy of the Divided Line, which illustrates the hierarchy of knowledge; and the Allegory of the Cave to relate how humans recover the knowledge of the Forms and thus gain an understanding of the highest form of reality. The scholar Rex Warner gives his insight into the Allegory of the Cave in his book, The Greek Philosophers, as such: “…He [Plato] seeks to make the reader grasp the full significance of progressive philosophical enlightenment; unless, he implies, we can progress in this direction, we remain in the Cave, the home of illusion and error, with, accordingly, no notion of the good life for ourselves and others, and thence no hope of bringing order into a distracted world.”


  • Fine, Gail (Editor). The Oxford Handbook of Plato. Oxford: Oxford University Press, 2011.
  • Grube, G.M.A. (Translator). Plato’s Republic. Indianapolis: Hackett Publishing Company, 1974.
  • Taylor, A.E. Plato: The Man and His Work. Mineola: Dover Publications, Inc., 2001.
  • Warner, Rex. The Greek Philosophers. New York: New American Library, 1986.

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2022 Doug West

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