Plato's Allegory of the Cave: Part I

Written by Dr. Jason Rheins on February 25, 2022

Plato’s “Allegory of the Cave” is arguably the most famous passage in the Western philosophical canon. It occurs at the beginning of Book VII of his Republic, just after the famous “divided line” and “analogy of the sun” at the end of Book VI. Socrates introduces the allegory as a way of characterizing the effects of education or its lack on human nature. In doing so, he relates the theory of levels of knowledge and reality proposed in the previous two analogies to the system of government and education in the Republic’s ideal state and clarifies his overall vision of the meaning, purpose, and challenges of education.

True education, it turns out, amounts to reorienting the entire human soul, but its intelligence most of all, away from the shadows of the visible, mundane world and toward the light of goodness and a higher, intelligible reality. As we will see, education involves at least two kinds of shock or disorientation—that of the darkened mind of the ignorant to light and that of the illuminated mind readjusting to the darkness in which the uneducated dwell. In this series of posts, I’ll provide a running commentary to explain what is going on at each point in the allegory, and in the final post, I will identify some worthwhile lessons in the passage that are worth keeping even if we reject Plato’s overall view of knowledge and reality. In this first post, though, my aim will be to explain the basic idea of the allegory and Plato’s comparison between us and the prisoners of his cave.

Republic VII.514a-515c

“Next,” said I, “represent our nature with respect to both education and the lack of education through this experience. Picture men dwelling in a sort of subterranean cavern with a long entrance open to the light on its entire width. Conceive them as having their legs and necks fettered from childhood, so that they remain in the same spot, able to look forward only, and prevented by the fetters from turning their heads. Picture further the light from a fire burning higher up and at a distance behind them, and between the fire and the prisoners and above them a path along which a low wall has been built, as the exhibitors of puppet-shows have partitions before the men themselves, above which they show the puppets.” “All that I see,” he said. “See also, then, men carrying past the wall implements of all kinds that rise above the wall, and human images and shapes of animals as well, wrought in stone and wood and every material, some of these bearers presumably speaking and others silent.” “A strange image you speak of,” he said, “and strange prisoners.” “Like to us,” I said; “for, to begin with, tell me do you think that these men would have seen anything of themselves or of one another except the shadows cast from the fire on the wall of the cave that fronted them?” “How could they,” he said, “if they were compelled to hold their heads unmoved through life?” “And again, would not the same be true of the objects carried past them?” “Surely.” “If then they were able to talk to one another, do you not think that they would suppose that in naming the things that they saw they were naming the passing objects?” “Necessarily.” “And if their prison had an echo from the wall opposite them, when one of the passersby uttered a sound, do you think that they would suppose anything else than the passing shadow to be the speaker?” “By Zeus, I do not,” said he. “Then in every way such prisoners would deem reality to be nothing else than the shadows of the artificial objects.” “Quite inevitably,” he said.

To begin, we should understand the basic image that Socrates asks his interlocutors to imagine. The cave in question has a long entrance; at 515e we further hear that “the ascent” up out of the cave “is rough and steep”. The key persons in the allegory are the prisoners, who are bound by neck and foot so that they cannot even turn their heads. They must stare ahead at a wall opposite them. Above and behind them a fire burns, and between them there is a wall with a raised path. The wall is used just like a puppeteer’s screen, for behind it, men walk past carrying implements–solid images in the shapes of men and animals that stick out above the top of the wall. Some of these image-bearers speak and others keep silent, but the light of the fire casts shadows of the objects that they carry on to the wall the prisoners gaze upon. [See the image below].

Glaucon reacts that this is a very strange image and very strange prisoners, but Socrates insists that they are like us. The prisoners have no other knowledge of their own bodies or those of their fellow prisoners than the faint shadows that they might cast. When they refer to the shadows they see passing on the wall, e.g. saying “horse” when a horse-shaped shadow passes by, they would take themselves to be referring to the actual objects, i.e. they would think that “horse” just means a horse-shaped shadow, not the animal itself that we know of. Likewise, hearing the echoes of the image-carriers, they would take the shadows to be the speakers of these echoes. Socrates sums up that, “in every way such prisoners would deem reality to be nothing else than the shadows of the artificial objects.”

But, how does that make them like us? Like us, they are confused about their own nature, taking their shadows for themselves. This may be Plato’s suggestion of the way that people identify more with their bodies than their souls and more with the lower parts of their souls (their emotions and appetites) than with their reason. More pointedly, Socrates is building on the theory of reality and knowledge laid out in the previous two books of the Republic as well as some of Plato’s earlier works such as the Symposium and Phaedo. In these, Plato’s Socrates distinguishes between sensible “becoming” and intelligible “being”. The world revealed by sense perception is an ever-changing realm of appearance, where many things temporarily and imperfectly imitate or partake in real, intelligible beings. These timeless and perfect beings are what Plato calls the “Forms” or “Ideas” (among other things).

For instance, you see a flower that is beautiful, but it is only beautiful in some ways, not others. And it will only be beautiful for the brief time between when it blooms and when it starts to fade and decay. It never is “beauty as such”, since Beauty itself is never ugly; it only comes-to-be or “becomes” beautiful for a time and then ceases to be so. However, we can recognize that beauty itself is never ugly. We can know this. Where do we get this knowledge and what is it about?

First, it cannot be knowledge about sensible objects (bodies and their images) perceived through the senses. Cognition, for Plato, is only as good as its objects. Certain knowledge requires unchanging realities, while the objects we perceive through the senses are constantly changing. As such, they can only ground opinions. For example, one can have true opinions that ‘this flower is beautiful’ or ‘this flower is not ugly’. They will be true in some senses (not others), for some time, but they will not always be true, and they will never be unconditionally true. On the other hand, if knowledge is something timeless, then knowledge cannot be about visible, “becomings”. The world of the senses is too unstable to bear the weight of knowledge. One might be able to have opinions that ‘this flower is beautiful’ or ‘this flower is not ugly’ which are true in a sense, for a time, but they will not always be true, and they will never be unconditionally true.

But what about when we say that Beauty is never ugly and Ugliness is never beautiful? This is certain, timeless knowledge, but it is not about the temporary and imperfect beauty in any sensible object. The ideal thing that we talk about when we know that Beauty is the opposite of Ugliness or that Beauty is good is instead an intelligible thing. Beauty itself, (aka the Form of Beauty, aka the Idea of Beauty) is not something grasped with the eyes of the body, but with the “eye of the soul”, that is, the intellect. Abstract things like Beauty, Justice itself, Courage itself, Flower itself, the Double, the Triple, and so on are, according to Plato, “really real” beings and the true objects of proper knowledge.

The Forms cannot be grasped with the senses, but they do have sensible reflections or shadows. A beautiful painting reflects or partakes in beauty. Contemplating it and asking the right kinds of philosophical questions might even spark in the immortal part of our soul a recollection of the Form of Beauty or awaken the intellect to it. But the most beautiful flower, or painting, or human face, or sunset is still only a shadow of Beauty.

How then are we like the prisoners in the cave? Like them, most of us take the physical objects we deal with on a day-to-day basis to be real reality. We think that words like “beautiful” or “flower” actually refer to this lily or that rose. But in this, Plato thinks, we are much mistaken. Sensible objects are only the dim shadows of intelligible beings, “flower” properly refers to the Form of Flower, not this temporary shadow of it that will soon wither in my vase. To the extent that we take the sensible to be what is most real and either fail to recognize the intelligible or regard it as some kind of less real abstraction, we are prisoners of ignorance, so benighted as to think shadows more real than what casts them, and darkness more illuminating than light.

Is Plato’s comparison a fair one? If we reject his view that the visible world of physical objects is a poor reflection of the realm of Ideas, then it certainly seems less apt to think that everything we think is real and knowable is mere shadow and echo. But even if we do reject Platonic metaphysics—as I think we should—there still is a salient point. Living in ignorance does not present itself as a total absence of discussion or concerns, but as immersion in a demimonde of chatter about ephemera, superstition, conspiracies, misinformation, and magical thinking. We take these things not only for real but for really important, and may remain in ignorance about how our physical and social world really works.

In the next part in this series, we will examine what Plato has to say about the transition from darkness to light and the resistance that enlightenment faces.

Dr. Jason Rheins

Dr. Jason G. Rheins is a scholar of ancient Greek and Roman philosophy. In 2003 he received his BA with honors in Philosophy and Classical Studies from Stanford University. In 2010 he earned his PhD in Philosophy from the University of Pennsylvania. He has taught or held professorships at the University of Pennsylvania, Swarthmore College, UNC Chapel Hill, St. John’s University, and Loyola University Chicago. He has published articles and book chapters on the history of philosophy, the philosophy of science, and metaphysics. He is currently completing a monograph on Plato’s theology.