In "The Allegory of the Cave," Plato uses the metaphor of an obscure cave to represent both knowledge and truth. This dark cave, illuminated by a fire at its end, entraps individuals who are chained by their legs and their necks, prisoners of the dark who are unable to move or turn in any direction. They can only see before them, visualizing mere shadows on the wall of the cave, and knowing these images as their only truth. One of the prisoners is finally freed from his bondage, and although he is first blinded, then pained and irritated by the light, he finally comes to understand the reality about him. Upon returning to the darkened cave, he is seen by his former peers as a man who lost his sight, but now, he can see all the more clearly. The truth sets him free.
Plato's allegory is based upon the concept of truth. It is about shedding fixed notions of reality and finding out, for oneself, what truth actually is. At the same time, this allegory proves that knowledge is useless unless one is in the light. The highly educated prisoners are no closer to the light than the less educated ones. However, once one is infused with knowledge, with the light of truth, one is "better able to share in double duty." With true knowledge comes the responsibility of bringing others into the light, by returning to the darkened cave, like Jesus did, to raise others up into the new world. Humans learn by experience, and only by realizing and then rejecting darkness, will prisoners see the light at the end of the cave.