This part of Plato’s philosophy is perhaps the most well-known of his many contributions to ancient Greek thought. Not only did it become the foundation for his political theory, but it even became a kind of paradigm for the Western view of reality as a whole. Here, in Book Seven of his Republic, Plato offers an allegorical account of how he sees the nature of reality and our knowledge thereof. It is possible that no other image of such matters has had more influence in Western thought than that of “The Cave.”
Plato begins by drawing a picture of a person in chains at the bottom of a cave with his vision, or understanding, limited to the shadows he sees on the cave wall cast by various objects passing before the light from a fire that exists outside of the cave. The prisoner and his colleagues pass the time trying to guess what the objects are passing in front of the light of the fire. Obviously, this “game” is fruitless as regards coming to know what the objects actually are, even though in this very primitive setting the guesses pass for knowledge.
Now, Plato surmises, if the prisoners were to be freed from their chains and able to find their way up and out of the cave, they would be on their way to acquiring actual knowledge of the reality outside of the cave. He likens their struggle up and out of the cave to that of a child initially finding its way around in the world. Our pilgrim is at first blinded by the light of the fire and all that it reveals about reality. At first, he discerns various objects being carried bye in front of the fire that are actually the items casting the shadows on the wall of the cave. He now understands that these items, and not the shadows, are the real objects of knowledge. However, he also soon discovers that these objects are themselves only physical copies of still other, actually more real objects in the world.
Plato suggests that even such objects are themselves only copies of the various “Ideas” or “Forms” that make up the ultimately real world lying behind the world of physical objects and making them possible. This world of ideas is what is “really real”, while all the rest is mere shadows and copies. It is here that the ideas such as Goodness, Justice, and Beauty reside, in the world of Ideas, not in the physical world. Plato argues that once a person actually encounters this real world of Ideas and Forms he or she will never wish to return to the world of physical reality, never ground their values in the anything other than pure ideas and truth.
Of course, Plato’s real purpose in developing this allegory was to provide a solid background against which to show how and why an effective and honorable political government must ultimately be based on solid ideas and those who know how to follow them. He calls such leaders “Philosopher Kings” and claims that those alone who have struggled their way up out of the cave of ignorance into the world of Ideas would be fit to rule a government effectively and honorably. Plato argues that they should not have any money or possessions of their own. He goes on to develop strict ideas about how these rulers would be educated. He argues that they should not have any personal life of their own so that they can be devoted entirely to the welfare of the State.
Plato actually made two trips to Syracuse in Italy trying to convince his friend the ruler there to institute his ideas but to no avail. Plato’s “Allegory of the Cave” has greatly influenced Western thought, both in its metaphysical and political development. At the same time, it has helped shape our ideas about education and knowledge. Moreover, the image of reality as a cave and education as the way out of ignorance has played an important role in guiding many thinkers’ ideas about how best to go about gaining knowledge. Indeed, Christian thinkers such as Augustine took Plato’s image as a blueprint for understanding the way humans should come to a knowledge of God through developing an understanding how God has structured the cosmos and how we can gain knowledge thereof.