The realm of material objects is the realm of mere opinion. His famous analogy of the cave illustrates this. In The Republic Plato tells an imaginary story of men who have lived in a cave as prisoners since childhood. They are chained and immobile. Their field of vision is restricted to a wall directly in front of them. Behind them is an elevated area where people are walking, carrying objects made of wood, stone, and other materials. The glow from a fire casts shadows of the people on the wall that