Allegory of the cave

Three higher levels exist: natural science; deductive mathematics, geometry, and logic; and the theory of forms.

Socrates explains how the philosopher is like a prisoner freed from the cave and comes to understand that the shadows on the wall are not the direct source of the images seen.

Plato begins by having Socrates ask Glaucon to imagine a cave where people have been imprisoned from childhood.

These prisoners are chained so that their legs and necks are fixed, forcing them to gaze at the wall in front of them and not to look around at the cave, each other, or themselves (514a–b).

The light would hurt his eyes and make it difficult for him to see the objects casting the shadows.

In his pain, Socrates continues, the freed prisoner would turn away and run back to what he is accustomed to (that is, the shadows of the carried objects).

[2] The prisoner would be angry and in pain, and this would only worsen when the radiant light of the sun overwhelms his eyes and blinds him.

[2] (See also Plato's analogy of the Sun, which occurs near the end of The Republic, Book VI.

[2] The returning prisoner, whose eyes have become accustomed to the sunlight, would be blind when he re-entered the cave, just as he was when he was first exposed to the sun (516e).

[6] Socrates informs Glaucon that the most excellent people must follow the highest of all studies, which is to behold the Good.

Those who have ascended to this highest level, however, must not remain there but must return to the cave and dwell with the prisoners, sharing in their labors and honors.

[7] Scholars debate the possible interpretations of the allegory of the cave, either looking at it from an epistemological standpoint—one based on the study of how Plato believes we come to know things—or through a political (politeia) lens.