Plato's allegory of the cave

Plato wrote the Republic as a conversation. In Book 7, Socrates asks Glaucon, who was Plato's own brother, to imagine this scene (514a–517a).

• People live in an underground cave, a σπήλαιον. They have been chained by the legs and neck since childhood, so they can only look straight ahead.
• Behind them, higher up, burns a fire. Between the fire and the prisoners runs a path with a low wall, like the screen of a puppet show. People walk along it, holding up objects and figures of humans and animals.
• The prisoners see only the shadows, the σκιαί, on the part of the cave in front of them. When a carrier speaks, the echo seems to come from a shadow. So they think the shadows are all that is real.
• One prisoner is freed and dragged up into the daylight. The light hurts his eyes. He sees shadows first, then reflections in water, then the things themselves, then the night sky, and at last the sun.
• He goes back down to his old seat. Now he cannot see in the dark, and the others laugh at him. They would kill anyone who tried to free them.

«A strange image», says Glaucon. «ὁμοίους ἡμῖν», answers Socrates: «like us» (515a).

«Allegory» is our word. Socrates calls the story an εἰκών, an image, and he explains it himself (517a–c). The prison stands for the world we see around us, and its fire for the power of the sun. The climb is the soul's rise to the νοητὸς τόπος, the region reached by thought alone. He adds a caution: «θεὸς δέ που οἶδεν», God knows whether this is true (517b).

Last and hardest to see is ἡ τοῦ ἀγαθοῦ ἰδέα, the Form of the Good (517b–c). Plato's Forms are the unchanging realities behind the things we perceive. Once seen, the Good must be recognised as the cause of everything right and beautiful, and whoever is to act wisely, in private or in public, must have seen it.

The cave completes a series of three images: the Sun and the Divided Line come just before it in the dialogue.

The first sentence says that the image concerns our nature «παιδείας τε πέρι καὶ ἀπαιδευσίας», in respect of education and the lack of it (514a). Socrates draws the conclusion at 518b–d. Some people claim to put knowledge into the soul, like sight into blind eyes. He answers that the power to learn is already there. Education is the art of turning the soul around, the περιαγωγή, towards what is real.

Then comes the hard question. Those who reach the top do not want to come back, but the founders of the ideal city must not let them stay (519c–d). Glaucon objects that this wrongs them. Socrates replies that the law looks after the whole city, not one group, and tells them: «καταβατέον», down you must go, each in turn (520c). Then the city will be run by people awake, not by rivals fighting over shadows, «σκιαμαχούντων».

Scholars still debate why philosophers would agree: Socrates repeatedly says they must be compelled to rule, and it is disputed whether justice alone moves them. The text also never names Socrates' own death in 399 BC, but many readers hear it in the threat at 517a.

Much of the scene can still be told with the same words. Το σπήλαιο του Δυρού is a formal name; in conversation Greeks say σπηλιά. Θέατρο σκιών, shadow theatre, is what Greeks call Karagiozis, though that puppet show has no historical link with Plato's image. Plato's puppet-showmen, the θαυματοποιοί (514b), are today's conjurors. A σκιαμαχία is now a useless fight against an enemy who is not there.

The είδωλο is still an image in a mirror, as the εἴδωλα in water were at 516a, but it can also be a pop idol. And παιδεία is on the door of the Υπουργείο Παιδείας, the ministry of education; «Ψωμί, Παιδεία, Ελευθερία» was the main slogan of the 1973 student uprising.