Plato and the Cave
Imagine an underground chamber, like a cave with an entrance open to the daylight and running a long way underground. In this cave are men who have been prisoners there since they were children, their legs and necks being so fastened that they can only look ahead of them and cannot turn their heads. Behind them and above them above them a fire is burning and between the fire and the prisoners runs a road, in front of which a curtain wall has been built, like the screen at puppet show between the operators and their audience. Imagine further that there are men caring all sorts gear along behind the curtain wall, including figures of men and animals made of wood and stone and other materials, and that some of these men, as is natural are talking and some not.
The bound men see only the shadows and they assume that the shadows are real people. If the curtain wall reflected sound, they would assume that the shadows are real people.
Suppose one of these men were let loose and suddenly compelled to stand up and turn his head and look and walk towards the fire. All these actions would be painful and he would be too dazzled to see properly the objects of which he used to see the shadows. So if he was told that what he used to see was mere illusion and that he was now nearer reality and seeing more correctly, because he was turned towards objects which were more real…don't you think he would be very confused.
If this man was now dragged out of the cave and saw the sun for the first time, he would be more dazzled still. In fact initially he would not initially be able to see any of those things which he was told were real. Gradually he might become accustomed to shadows outside the cave, then to other objects and finally he might be able to look at the sun itself. He will then be able to see objects as they really are and not as reflections and he will understand al things and be able to reason.
When he remembers those who are still down in the cave, he will pity them and wonders if he ought to return to them. He remembers the way in which they used to have competitions about observing the shadows. He knows that if he should return to that way of life, he would not be able to cope with the darkness, as now he had seen the light of reason. He would not be able to take part in the competitions about the order of the shadows and those in the cave would think that he was ridiculous. They would mock him and imply that to move out of the cave destroys the eyes. If he tried to loose another and lead him up to the light then they other prisoners would try to catch him and put him to death.