In 380 B.C. Plato described a group of prisoners that spent their whole lives in a cave. They were chained up with their heads stuck so all they could do was stare at the wall. There was a fire so that when people walked across the cave they would hold up random objects and the prisoners could only see the shadows.
So, they had seen nothing but shadows their whole lives so they think the shadows are the real things. They didn't have much to do. So, they gave names to the things they saw, and tried to show off by how quickly they could identify things.
