Copernicus and Galileo were mocked for their belief that the earth revolves around the sun, not quite so for their absurd theory in a world that believed the rise and set of the sun could only mean that the sun revolves around the earth, but rather due to a lack of knowledge of the audience. If one strongly believes in a certain theory, it may become difficult for them to see a contrasting idea. We fear what we do not know.
What Plato attempts at signifying through Socrates’s eyes in his book “Republic” (Book Seven) is a similar scenario, consisting of a group of prisoners who have been condemned to a dark cave, where it is ensured that they cannot move their heads, so that they may only see the wall ahead and the shadows cast from the fire behind them. He considers this hypothetical picture to mirror that of human knowledge, portraying that we know only what we see. The group of individuals consider only the shadows on the wall to be the entire universe, as that is all that they know.
He describes how if an individual from the group is abruptly forced to face the earth as we know it, away from the dreary cave and into the light, he would be shocked, intimidated, disturbed even. The change may not be welcome to him, nor is it probable that it would be much appreciated. He may rather choose to believe what he knew the world to be previously than what he is seeing now.
Slowly will the constraints of his mind unfold and gradually will he learn. He would learn to recognize items of nature, and then objects of astronomical study. Bit by bit will the reality become real to him. Then will he notice the sun, the great granter of light. His studies and observations would lead him to comprehend its intricacies, that it is an object on its own, and not a reflection, that it is the reason for the seasons, the reason he could see, the reason this world is so different from the one he once knew.
Taking a reroute back to present day, its unmistakably the same situation. We believe what we are told, we believe that which we see. But we fail to imagine what other knowledge there may be in the world and beyond which we have not yet been acquainted with. We may even shake our heads and let the thought pass, marking it as ridiculous. Similarly to the situation above, when we do discover new gen we are struck dazzled, and amazed, believing it to be the source of all reason, illuminating our once-dark mind on the matter.
Thus the allegory of the cave truly underlines the characteristics of human perception, portraying the difficulties in transition from either light to dark or light to dark, of comprehension and understanding and most importantly, analysis and acceptance of the vast world of knowledge.