http://www.thur.de/philo/philo5.htm

The cave parable

In his Politeia, Plato discusses the possibility of an ideal political order. In the question of whether and how men can be formed, Plato uses a parable, the famous cave-like paradise. It is about whether and how man can recognize the truth (Plato, p. 301ff.).

"Imagine people in a subterranean dwelling-place ... from childhood, they are tightly entangled in this cave... (They) look straight ahead ... from above, but from far away from backwards appears to them Fire, but between the fire and the tied one runs a path along which a low wall is erected ... Along this wall ... people carry all sorts of equipment ...

Can such prisoners have seen themselves as well as each other as the shadows thrown by the effect of the fire upon the wall of the cave opposite them? ... In the end, therefore, the prisoners would not accept anything but true as the shadows of the artificial objects.

If one of them were unleashed and compelled to rise suddenly, turn his neck, look up to the light ... And if he were forced to direct his light on the light itself, his eyes would hurt him. But if he were dragged from there by the force of the rising upwards, and did not rest until he had been brought to the light of the sun, he would not feel this violence painful and resist it? At last he would be able to look at the sun, not merely a reflection of it in the water ... in full reality ... and be able to consider its nature ...

If such a man descended into the cave, and there again occupied his old place, his eyes would not be formally submerged in darkness. And if he had to compete again ... in the interpretation of those shadows, ... he would not make himself ridiculous, and would not be called by him that his ascent to the top was to blame for it ... and already the mere attempt, To go upstairs is reprehensible?

So, we are in the real earth in a cave. Whoever comes to the surface realizes the real world.