Plato uses the cave as a metaphor for how humans live in the world, contrasting reality with our interpretation of it. These two ideas represent the story's two worlds: the world inside the cave and the world outside. For the prisoners in the cave, the shadows cast by the firelight on the wall are all that exists. If one of the prisoners escapes and witnesses the outside world, they will realise that this is the true reality. However, when the freed prisoner returns to the cave's darkness, their eyes will have been permanently damaged by the sun's brightness, leading their fellow inmates to mistakenly believe that the outside world is dangerous and that finding the truth is not worthwhile. The allegory explores the philosophical idea of truth and how people from different backgrounds or experiences may view it. The shadows on the cave wall change all the time, so there is no stability or consistency for those who witness them—only a false reality. They have no idea that the real world exists outside of their dark cave, or that there is another real world besides their own. Meanwhile, the person who left the cave will no longer be able to exist in the same way. They may even feel sorry for or superior to those who remain in the cave. The allegory essentially depicts the conflicts between knowledge and belief, as well as what happens to a person once enlightened. It examines the nature of humanity and the fear of the unknown.