Plato's cave explained: what the story says

Plato's cave is a story about the difference between what looks real and what is. People who have spent their whole lives chained in a cave, facing a wall, take the shadows on it for the world. Plato uses the image to describe education as a turn from appearances toward true understanding, and the story is also about how hard it is to go back and tell others.

The story

The cave appears in Plato's Republic, in Book VII. It is told as a conversation between Plato's brother Glaucon and Socrates, and Socrates is the one who narrates it.

Picture people who have been chained by their necks and legs all their lives, facing the bottom wall of a cave. Behind them a road runs across the cave, with a low wall beside it, and higher up there is a fire. Figures walk along the road, hidden by the wall, but they carry objects that stick up above it and cast shadows onto the wall in front of the prisoners. Some of the figures speak, and the prisoners take the echoes of their voices to belong to the shadows.

For the prisoners, the shadows are everything there is. Nothing in their lives gives them a reason to think there is anything else.

The climb

Now suppose one prisoner is freed and dragged by force up the rough, steep way out of the cave, and not let go until he is in the light of the sun.

At first he cannot see. His eyes adjust slowly. First he can make out only shadows, then reflections of people and things in water, and later the people and things themselves. The sight comes in stages, not all at once.

What it stands for

An allegory is a story that stands for something else. In the account of the Republic given by the Internet Encyclopedia of Philosophy, the cave represents the philosopher's education from ignorance to knowledge of the Forms. For Plato the Forms are the true objects of knowledge, as opposed to the visible things around us. True education, the entry says, is the turning around of the soul from shadows and visible objects to true understanding of the Forms.

The story belongs with two other images in the same part of the Republic. In the divided line, the lower two parts stand for the visible realm and the upper two for the intelligible realm. In the first section Socrates places images and shadows, in the second visible objects, in the third truths reached by reasoning from hypotheses as mathematicians do, and in the last the Forms themselves. The image of the sun stands for the Form of the Good, which, the encyclopedia says, makes the objects of knowledge knowable.

The return

The story does not end at the sun. The Internet Encyclopedia of Philosophy says that philosophers who reach this understanding will be reluctant to do anything but contemplate the Forms, and must be forced to go back to the cave, which stands for the city, and rule it.

In the story as told in the Republic, the prisoners left behind would, if they could, reach out and kill anyone who tried to drag them out of the cave. Plato is describing how much people may resist being told that what they take for the world is only a shadow of it.

What to take from it

You do not have to share Plato's picture of the Forms to find the story useful. It asks a question that is still argued: how do we know that what we take for plain fact is not a shadow of something else?

Plato's own answer puts the most reliable knowledge in reasoning about things the senses cannot reach. Many later thinkers answered the other way, that knowledge comes from experience. We set out both sides on the page about reason and experience, and the broader question of what truth is on the page about what is truth. You can read about Plato, Socrates and the school of thought called rationalism on their own pages.

If you would like to see where your own answers to questions like these place you on the map, you can take the walk.