Plato introduces the simile of the cave in the Republic to convey the power of the experience of forms and describe their importance. It is his metaphysics in a poetic nutshell. Imagine a cave where prisoners are chained to the wall and the only objects they can see are shadows of things carried behind a fire in back of them. If a prisoner is freed, he will first encounter the objects in the cave whose shadows he has seen before. If he ascends out of the cave, imagine his amazement when he sees these objects, and the rest of the world, in full sunlight. Imagine also how his fellow prisoners might react if he attempts to relate what he has seen to them. The cave represents normal existence and perception, and the objects in sunlight are the world of the forms.