The Allegory of the Cave

And now let me show in a figure how far our nature is enlightened or unenlightened. Behold human beings living in an underground den; here they have been from their childhood, and have their legs and necks chained so that they cannot move, and can only see before them, being prevented by the chains from turning round their heads. Above and behind them a fire is blazing at a distance, and between the fire and the prisoners there is a raised way; and you will see, if you look, a low wall built along the way, like the screen which marionette players have in front of them, over which they show the puppets. And do you see men passing along the wall carrying vessels, and statues and figures of animals made of wood and stone? To the prisoners, the truth would be literally nothing but the shadows of these images cast upon the wall before them.

And when one of them is liberated and compelled suddenly to stand up and turn his neck and walk and look towards the light, he will suffer sharp pains; the glare will distress him, and he will be unable to see the realities of which in his former state he had seen only the shadows. He will need to grow accustomed to the sight of the upper world, and only by degrees will he come to see the things themselves.