So imagine some people tied by their necks and legs in a cave. They are facing the wall of the cave, and because they are tied up, they can only face the wall of the cave. They cannot turn their head around. Now in the cave behind them there is a fire where they can see shadows. Now like a shadow puppet show, there is a wall so the people can hide while they operate the puppets. The people who are tied up, the slaves, see these puppets and see them as reality. Now also in the cave there are echoes ...