You are imprisoned in a cave, observing shadows on a wall, of people speaking to one another; you and your fellow prisoners accept this as reality.
You are freed from the cave by your captor, at first apprehensive, later overwhelmed and in awe with the reality you can now acknowledge to exist outside of the cave. The sheer amount of light blinds you at first, but you acclimate to fully understand and reason with it.
You return to the cave, now unable to see in such low light. Your prison-mates conclude that leaving the cave has blinded you, and commit to never leaving the cave, lest they risk permanent blindness.
The cave is the eternal center of the drama, and an unyielding source of light.