A group of prisoners were chained to a wall in a cave since birth and they had no knowledge of the outside world. They faced a blank wall with a fire behind them that cast a faint light onto the wall in front of them.
On the wall they saw shadows being projected; they saw objects and other animals’ shadows and gave these shadows names to classify them. They believed these shadows to be actual reality.
One day a prisoner was freed and brought to the outside world for the first time. When he saw the outside, the sun’s bright light almost blinded him and he found the new environment confusing and out of place because he had grown accustomed to the two-dimensional shadows in the cave. When he was told that all the objects he was now seeing were real and shadows just reflections, he couldn’t believe it.