Plato said that we may not be able to perceive reality. We may only perceive reality as shadows on the wall and miss our true existence. In Plato's Cave, he strapped a species into chairs to where they could not move. He also put up shields to where they could not see to their side. They could only see in front of them. They could talk to each other. He then built a campfire behind them and cast shadows on the wall. The strapped species would think that they were only the shadows and the voices they heard echoing off the wall were coming from the shadows. They would not know that they existed at all. Their total concept of reality would be the one orchestrated by Plato. A false one.