Plato asks us to imagine a cave where people have been imprisoned from childhood, but not from birth. These prisoners are chained so that their legs and necks are fixed, forcing them to gaze at the wall in front of them and not to look around at the cave, each other, or themselves Behind the prisoners is a fire, and between the fire and the prisoners is a raised walkway with a low wall, behind which people walk carrying objects or puppets "of men and other living things" The prisoners cannot see any of what is happening behind them, they are only able to see the shadows cast upon the cave wall in front of them. The sounds of the people talking echo off the walls, and the prisoners believe these sounds come from the shadows

The shadows are reality for the prisoners because they have never seen anything else; they do not realize that what they see are shadows of objects in front of a fire, much less that these objects are inspired by real things outside the cave which they do not see.

The fire, or human-made light, and the puppets, used to make shadows, are done by the artists.

Also, few humans will ever escape the cave.

A freed prisoner would look around and see the fire. The light would hurt his eyes and make it difficult for him to see the objects casting the shadows. If he were told that what he is seeing is real instead of the other version of reality he sees on the wall, he would not believe it. In his pain, Plato continues, the freed prisoner would turn away and run back to what he is accustomed to (that is, the shadows of the carried objects). He writes "... it would hurt his eyes, and he would escape by turning away to the things which he was able to look at, and these he would believe to be clearer than what was being shown to him."

Plato continues: "Suppose... that someone should drag him... by force, up the rough ascent, the steep way up, and never stop until he could drag him out into the light of the sun." The prisoner would be angry and in pain, and this would only worsen when the radiant light of the sun overwhelms his eyes and blinds him.

"Slowly, his eyes adjust to the light of the sun. First he can see only shadows. Gradually he can see the reflections of people and things in water and then later see the people and things themselves. Eventually, he is able to look at the stars and moon at night until finally he can look upon the sun itself

This prisoner would be excited about learning this truth and would wish to return to the cave to show the others in the cave what he has seen. Plato concludes that the prisoners would be angry and call this person crazy. If they were able, they would reach out and kill anyone who attempted to drag them out of the cave