Plato has Socrates describe a gathering of people who have lived chained to the wall of a cave all of their lives, facing a blank wall. The people watch shadows projected on the wall by things passing in front of a fire behind them, and begin to designate names to these shadows. The shadows are as close as the prisoners get to viewing reality. He then explains how the philosopher is like a prisoner who is freed from the cave and comes to understand that the shadows on the wall do not make up reality at all, as he can perceive the true form of reality rather than the mere shadows seen by the prisoners.
The allegory may be related to Plato's Theory of Forms, according to which the "Forms" (or "Ideas"), and not the material world of change known to us through sensation, possess the highest and most fundamental kind of reality. Only knowledge of the Forms constitutes real knowledge.[1] Socrates informs Glaucon that the most excellent must learn the greatest of all studies, which is to behold the Good. Those who have ascended to this highest level, however, must not remain there but must return to the cave and dwell with the prisoners, sharing in their labors and honors.
Plato's Phaedo contains similar imagery to that of the allegory of the Cave; a philosopher recognizes that before philosophy, his soul was "a veritable prisoner fast bound within his body... and that instead of investigating