Book VII of the Republic begins with a parable of sorts.[42] Plato tells the story of a group of prisoners chained in a cave next to one another so that they can only look forward to see shadows cast on the wall in front of them by a fire behind them. Various puppets are carried in front of the fire, casting shadows that the prisoners take to be real. They can talk with each other, and take the shadows of other prisoners as the persons they are talking with, and the echoes from the wall in front of them as the voices of their fellows.
Now imagine that one of them is freed from bonds and turned around. Surely he will be blinded by the fire that he sees for the first time and confused by the puppets he sees for the first time. As he is led outside into the sunlight, he will be blinded again and dazzled by the sights of objects he sees. He would at first see best at night, but gradually be able to bear the brightness of the sun so as to see objects in daylight. At this point he would have an adequate understanding of the world and the objects in it and be loath to return to the cave. Now imagine that he is led back into the cave. He will see poorly and try to tell his fellows of his discoveries in the upper world. But they will think him mad and resist any efforts he might have to release them and lead them to the light.
Plato now likens this parable to the situation in which philosophers find themselves. Having found their way to a higher understanding of the world, they struggle to communicate with the cavemen and -women they encounter the glories of the upper world—in this case the world of the Forms. For the hierarchy Plato has described of levels of reality and corresponding levels of understanding shows that most people grasp only shadows of what is real. The ultimate realities are the Forms, of which we perceive only imitations in the natural world. As the fire in the cave casts shadows on the wall, the sun outside the cave illuminates the upper world: the Form of the Good reveals the Forms to those who are ready to comprehend them.
And like the prisoner released from the cave, the philosopher has no wish to return to the gloomy nether world. Yet the philosopher-kings and -queens are sent back to the ideal state to manage its affairs and rule its benighted citizens. The Cave analogy, then, is a kind of dynamic representation of how those who achieve enlightenment fare as they ascend from the level of shadows to objects to mathematical entities to Forms. They resist at first, but ultimately they are overwhelmed with and captivated by the beauty and glory of the upper realms, and lose all desire to muck about in the Slough of Despond that is the world of everyday experience. Indeed, Socrates points out, the fact that philosophers are so reluctant to rule provides the best safeguard for society from power-hungry rulers.[43]
On this account, then, education is not a matter of putting knowledge into empty heads, like putting sight into blind eyes. Rather, given that one already has the power of vision, education is an art (technē) of turning someone around to face the light (as in the cave); it is an art of reorientation, of conversion.[44]
The art of reorientation has a name: dialectic (dialektikē).[45] It looks a lot like Socrates’ art or practice of elenchus, or refutation, often consisting of seeking definitions of the objects being studied and criticizing them. But now the practice has a positive orientation of its own: it aims not at eliminating false definitions and conceptions (to arrive at the one true and irrefutable account), but at discovering the true natures of things, and connecting them together in a constructive account of things. Progress now is marked not by elimination of false paths, but by the reconstruction of true ones.
[42] Plato Republic VII, 514a-517c.
[43] Plato Republic VII, 520c-d.
[44] Plato Republic VII, 518b-d.
[45] Plato Republic VII, 532b.