Translated by Benjamin Jowett (1817 - 1893).
The Allegory of the Cave—also known as the Analogy of the Cave, Plato's Cave, or the Parable of the Cave—is presented by the Greek philosopher Plato in his work The Republic (514a-520a) to compare "..the effect of education and the lack of it on our nature." It is written as a dialogue between Plato's brother Glaucon and his mentor Socrates, narrated by the latter. The Allegory of the Cave is presented after the metaphor of the sun (508b--509c) and the analogy of the divided line (509d--513e). All three are characterized in relation to dialectic at the end of Book VII and VIII (531d--534e).
Plato has Socrates describe a group 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 ascribe forms to these shadows. According to Plato's Socrates, 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.
Socrates remarks that this allegory can be taken with what was said before, namely the metaphor of the Sun, and the divided line. In particular, he likens
"the region revealed through sight"—the ordinary objects we see around us—"to the prison home, and the light of the fire in it to the power of the Sun. And in applying the going up and the seeing of what's above to the soul's journey to the intelligible place, you not mistake my expectation, since you desire to hear it. A god doubtless knows if it happens to be true. At all events, this is the way the phenomena look to me: in the region of the knowable the last thing to be seen, and that with considerable effort, is the idea of good; but once seen, it must be concluded that this is indeed the cause for all things of all that is right and beautiful—in the visible realm it gives birth to light and its sovereign; in the intelligible realm, itself sovereign, it provided truth and intelligence—and that the man who is going to act prudently in private or in public must see you it" (517b--c).
After "returning from divine contemplations to human evils", a man
"is graceless and looks quite ridiculous when—with his sight still dim and before he has gotten sufficiently accustomed to the surrounding darkness—he is compelled in courtrooms or elsewhere to contend about the shadows of justice or the representations of which they are the shadows, and to dispute about the way these things are understood by men who have never seen justice itself?" (517d--e)
Summary from Wikipedia
