The allegory of the cave is that a tale from Plato’s Republic reporting a conversation between Galucon and Socrates.
Socrates tells Glaucon about a group of prisoners chained up in a cave. They couldn’t see out but they could see shadows on the wall of the cave of things that passed the entrance of the cave. Knowing no better the prisoners thought that the shadows were reality. And so it went on.
After some hours, or days, or years, one of the prisoners broke her chains and escaped. Emerging from the cave she found the light outside the cave blinding. She wanted to return to what she knew but something made her stay out. Over time her eyes adjusted and she realised that the shadows in the cave were just that, shadows. The real world was more wonderful and varied and beautiful than she could ever have imagined.
Having seen what life was really like she wanted to liberate the friends that she had left in the cave so she went back. But when she got their her friends refused to believe her and drove her out. In sadness, she turned back to the sun and left.
