Knowledge and Opinion
For Plato, knowledge gained through the senses (empirical experience) is no more than opinion. Knowledge gained through philosophical reasoning is certain.
The allegory of the cave makes a contrast between people who see only appearances and mistake them for the truth, and those who really do see the truth.
Some prisoners are trapped in a cave, away from a “real life.” The prisoners are chained and only able to look straight ahead at a wall in front of them, whilst there is a fire behind them. Between them and the fire is a kind of track with a parapet in front of it, rather like the stage of a puppet show.
People can carry a variety of artificial objects made from wood and stone along the track making them move and sometimes giving them voices – like the puppeteers of a puppet show.
Shadows of the puppets are cast up on the wall in front of the prisoners caused by the fire. Since the wall is the only thing the prisoners have ever known, they are lead to believe that these shadows are entities in themselves and the only reality. Due to the flickering fire the shadows are poor quality and are merely images of artificial objects imitating real objects that exact in a reality the prisoners are not aware of.
The prisoners experience echoes of the puppeteers pretending to be the artificial objects.
The prisoners thus have an experience similar to that of an underground cinema. Their experience of reality is far removed from the everyday world - they see poor shadows of artificial objects pretending to move and hear echoes of sound that does not really come from the shadows they attribute them to.
Plato suggested prisoners may have made up a game where they observe shadows passing by and remember their order of appearance so can make good guesses about which object will come next. This requires no philosophical insight, just a skill at guesswork. A person with real knowledge will understand that this skill has no value compared with a genuine understanding of reality – the world outside of the cave.
Eikasia Derived from "Eikon" - an image or likenes
Eikasia is the state of mind Plato refers to when discussing the prisoners in the cave – the lowest level of understanding.
Plato explains a series of events in which one prisoner is set free. He can stand up and turn around – finds movement painful at first, and is too dazzled by the light form the fire to see anything properly.
This illustrates how the first response to philosophical questioning is puzzlement
As he becomes used to the light he realizes that his former view of reality was not accurate. Looking at the fire makes him uncomfortable and he wants to go back to looking back at the shadows again, when he was happy with his interpretation of the world. However he is forced outside in what Plato describes as a steep and rough journey. He as so dazzled by the sun at first he cannot see anything. However, the more his eyes get used to the world outside the cave the more he is able to perceive. He is able to look into the sky at nighttime first and then eventually at daytime.
He is able to see the real world and draw conclusions from it which are true
He begins to understand that the world depends on the sun for existence, the source of all light, reflections and shadows. The sunlight thus is representative of true knowledge. He is aware that his earlier understanding of the world is wrong and realises that the former skills prized by the prisoners (their game) are worthless.
The escapee or former prisoner feels sorry for others in cave, goes down to tell them. His ability to see the shadows on the wall has deteriorated since his sight has been adjusted to the sunlight of the outside world. The other prisoners laugh at him and say his journey into the light was a waste of time because it spoiled his ability to see clearly. They threaten to kill anyone who attempts to set them free – they are afraid of philosophical enlightenment.