Imagine you have been imprisoned all your life in a dark cave. Your hands and feet are shackled and your head restrained so that you can only look at the wall straight in front of you. Behind you is a blazing fire, and between you and the fire a walkway on which your captors carry statues and all sorts of objects. The shadows cast on the wall by these objects are the only things you and your fellow prisoners have ever seen, all you have ever thoughts and talked about.
Now suppose that you are released from your shackles and free to walk around the cave. Dazzled at first by fire, you will gradually come to see the situation of the cave properly and to understand the origin of the shadows that you previously took to be real. And finally you are allowed out of the cave and into the sunlit world outside, where you see the fullness of reality illuminated by the brightest object in the skies, the Sun.
In his Allegory of the Cave Plato sets out to do more than illuminate his distinctive views on reality and our knowledge of it. This becomes clear in the final part of the story. Having ascended to the outside world and recognized the nature of ultimate truth and reality, the released prisoner is anxious to re-enter the cave and disabuse his benighted former companions. But accustomed now to the bright light of the world outside, at first he stumbles in the darkness of the cave and is considered a fool by those who are still held captive. They think that his journey has ruined him; they don’t want to listen to him and may even try to kill him if he persists. In this passage Plato is alluding to the usual plight of the philosopher – ridicule and rejection – in attempting to enlighten ordinary people and to set them on the path to knowledge and wisdom.
50 Philosophy Ideas, Ben Dupre, 8 – 11