Book VII evokes an “image” of the nature of human beings. In this image, Socrates likens human beings to slaves bound in a long, dark cave since birth. At the back of the cave is a trail leading up to the light, but people cannot see the light as they are shackled to the floor such that they may only see the shadows and reflections of things on the walls. These shadows and reflections, they think, are all that is. At the back of the cave is a short wall where puppet handlers make demonstrations that reflect onto the cave walls. The demonstrations are made of various materials and they caricature animals, and men and other things. Some speak and others are silent. There is a fire burning in the cave which casts the shadows.
Next we encounter an educator who compels a prisoner to stand up and turn around to see the light. It would take the student a long time adjust in seeing things as they are, but would be happier for it and pity the others. If he were to return to his former seat, the others would surely laugh at him as if it was not worth it and they would surely try to kill him (517a).
By the present argument, each soul has it in them to be reoriented, by the art of “turning around”, to see that which is coming into being together with the soul. The brightest part of that which is is said to be the good. The governors of the city should be neither the uneducated, nor the overly educated. Therefore it is the job of Socrates and Glaucon, as founders of the city, to determine the best of natures and compel to go into the greatest study. It is, therefore, an education for the purposes of governing. The goal is for a good and well-harmonized city, not the benefit or pleasure of any one man.
Also, in each regime are philosophers. These strange beings grow up spontaneously against the will of the regime. They must habituat themselves and go down into the city to see the dark things of the cave. The city in which the leaders are least eager to rule is the best and freest from faction. When ruling becomes a thing fought over and the leaders go to the city for want of private goods, like beggars, the city destroys itself.
They discuss the importance of music and gymnastics in educating souls for reorientation from the cave, as well as geometry, in the study of number. The process by which one learns and goes up out of the cave into the sunlight is best expressed in the dialectic. Lastly, the natures of the rulers are reiterated and Socrates reminds Glaucon that both and women may rule, as is in their natures. They conclude Book VII in agreement about the nature of the rulers and how they must be educated.