The following is an excerpt from Plato’s dialogue called “The Republic.” In this section of the dialogue called the “Allegory of the Cave,” Socrates creates an allegory to help illustrate his theory of knowledge.
“Now then,” Socrates said, “let me tell you a story about ignorance and education which will explain the condition of man’s nature. Imagine that there is an underground cave with a long entrance open to the light. In this cave men have been chained from birth, fettered by the neck and legs so they cannot move. They cannot turn their heads around; they can only look forward at the wall of the cave. A light comes to them from a fire burning some distance behind them. Between the fire and the chained men is a raised platform on which a low wall has been built. Behind the wall are people, like puppeteers, who carry all sorts of articles like statues of men and other living things which they hold above the wall. Some of the bearers speak and others are silent, as you might expect.”
“I see,” said Glaucon [Socrates’ student]. “Truly a strange place and strange sort of people.” “Actually, they are just like ourselves.” Socrates explained, “What do you think these chained men would know of themselves or each other or anything else? They will know only the shadows which the firelight casts on the opposite wall of the cave.”
“They could not know anything else if they were chained so that they could never turn their heads,” exclaimed Glaucon.
“True;; and what about the things being held above the wall? Would not they only know the shadows of these things?” asked Socrates.
“Of course,” Glaucon answered.
“Suppose the prisoners could talk to each other;; and they named the passing shadows.
Would they believe they were naming real things?”
“Then suppose the cave had an echo so that when one of the people passing behind the wall spoke, the chained prisoners would think that the sounds originated with the shadows.
Would they not think that the shadows of the objects were real?”
“Surely they would,” said Glaucon.
“Now consider what would happen,” Socrates continued, “if one of the prisoners would be released from his chains. He would be forced to stand up and turn around, to walk and look at the firelight. Would he not find this painful? Would he not be too dazzled by the light to see clearly those things whose shadows he had seen on the wall? What do you think he would say if someone told him all that he had seen before was merely an illusion, but now he could see more clearly being closer to reality? What if he were shown each of the items which cast the shadows; would he not be confused and be sure that what he had seen before was more real than what was being shown him now?”
“He would surely be confused,” Glaucon exclaimed.
Socrates went on. “Then suppose he were made to look towards the great light coming from the entrance to the cave; would that not hurt his eyes? Would he not prefer to look upon those things being shown him?”
“Of course,” answered Glaucon.
“Now, let us suppose that someone would force him to approach the light and then dragged him up the steep and rugged pathway and out into daylight. Would he not then be distressed? When he came into the light of the sun the brilliance would blind him. He would not be able to see any of the things that we would call real.”
“No,” Glaucon said, “not at first.”
Socrates continued, “He would surely have to get used to the light. At first he would most easily look at the shadows, then at reflections in the water, and finally he would find it easier to study the night sky and the light of the stars and the moon, than to look at things in…