In Plato's "The Allegory of the Cave," he suggests that there are two different forms of vision, a "mind's eye" and a "bodily eye." The "bodily eye" is a metaphor for the senses. While inside the cave, the prisoners function only with this eye. The "mind's eye" is a higher level of thinking, and is mobilized only when the prisoner is released into the outside world. This eye does not exist within the cave; it only exists in the real, perfect world.
The "bodily eye" relies on sensory perceptions about the world in order to determine what is reality. Metaphorically speaking, the cave is a physical world filled with imperfect images. This world is filled with distorted images about reality. .
Inside the cave, the prisoners believe that the shadows they see on the wall are actual reality. Their "bodily eye" tells them that this world is real because their senses perceive so. Plato suggests that the senses do not perceive actual truth.
The "mind's eye" is not active inside the cave because the prisoners are imprisoned in this distorted world, which they believe is reality. When one prisoner is pulled out of the cave and into the light, it is this sudden freedom that starts the gradual process of enlightenment. This sudden freedom opens the "mind's eye". The prisoner "will be able to see the sun, and not mere reflections of him in the water, but he will see him in his own proper place, and not in another; and he will contemplate him as he is" (279). He then begins to understand that there is a reality higher than that which was previously believed.
There is a concrete difference between the two eyes discussed by Plato. The "bodily eye" lives in the distorted world of sense perceptions; the imperfect world which people experience with their physical senses. In the cave, there were "men passing along the wall carrying all sorts of vessels, and statues and figures of animals made of wood and stone and various materials" (278).