Plato's Cave: illusions

In Plato's "The Republic", Socrates describes a scene from the cave, whereby a group of people have lived chained to the wall in a cave all of their lives, facing a blank wall.

The people watch shadows projected on the wall by objects passing in front of a fire behind them. They begin to ascribe forms to these shadows.

According to Socrates, the shadows are as close as the prisoners get to viewing reality. He then explains how the philosopher is like a prisoner who is freed from the cave and comes to understand that the shadows on the wall are not constitutive of reality at all, as he can perceive the true form of reality rather than the mere shadows seen by the prisoners.

The shadows are an illusion of reality for the cave-dwellers.

Socrates next asks Glaucon to consider the condition of this philospher who returns to the cave after his awakening:

"Wouldn't he remember his first home, what passed for wisdom there, and his fellow prisoners, and consider himself happy and them pitiable? And wouldn't he disdain whatever honors, praises, and prizes were awarded there to the ones who guessed best which shadows followed which? Moreover, were he to return there, wouldn't he be rather bad at their game, no longer being accustomed to the darkness? Wouldn't it be said of him that he went up and came back with his eyes corrupted, and that it's not even worth trying to go up? And if they were somehow able to get their hands on and kill the man who attempts to release and lead up, wouldn't they kill him?"