“...Imagine people living in an underground space, like a cave, with an opening far above them that lets in a bit of light. They’ve been there since childhood. Their legs and necks are fixed so they can’t move. They can only look straight ahead. They can’t turn their heads.

Behind them, at a distance, there’s a fire. Between the fire and the people, there’s a raised path. Along that path, others walk back and forth carrying objects. Figures of people, animals, all kinds of things. There’s a low wall along the path, like a screen, so only the tops of these objects are visible.”

“I can picture it,” he said.

“The people sitting there can only see the wall in front of them. The fire behind them casts shadows of those objects onto the wall. So all they ever see are shadows.”

“That would be their whole world,” he said.

“Exactly,” I said. “And if they talk to each other, they’d be naming those shadows, thinking they were talking about real things.”

“Of course.”

“And if there were echoes in the space, so that sounds bounced back from the wall, they’d think the shadows themselves were making the noise.”

“That makes sense.”

“To them,” I said, “the truth would be nothing more than those shadows.”

“Yes.”

“Now imagine one of them is freed. He’s forced to stand up, to turn around, to look toward the fire. It would hurt. His eyes wouldn’t know what to do with the light. He’d be confused. He might even think what he’s seeing now is less real than the shadows he’s used to.”

“That seems likely.”

“And if someone tried to explain it to him, showed him the objects casting the shadows, he might not believe it. He’d still trust what he’s always known.”

“Right.”

“And if he’s dragged further, up toward the opening, into real daylight, it gets worse before it gets better. The light would overwhelm him. At first he wouldn’t be able to see anything clearly at all.”

“He’d want to go back.”

“Probably,” I said. “But if he stayed, his eyes would adjust. Slowly. First he’d see shadows again, but now outside. Then reflections in water. Then the objects themselves. Eventually he could look at the sky, the stars at night, and finally the sun itself.”

“And then he’d understand,” he said.

“Yes,” I said. “He’d start to see that what he knew before was only a small part of what’s real. Not completely false, but incomplete.”

“And if he thought about the others still in the cave?”

“He’d feel for them,” I said. “He might even want to go back and tell them.”

“And what would happen then?”

“If he went back down,” I said, “his eyes would struggle to readjust to the dark. He wouldn’t see the shadows as clearly as before. The others would notice. They’d think something was wrong with him. That leaving made him worse, not better.”

“And if he tried to free them?”

“They wouldn’t trust him,” I said. “They might even turn on him. Because to accept what he’s saying, they’d have to question everything they’ve built their understanding on.”

There was a long silence after that.

“The point,” I said quietly, “is that moving toward what is more real isn’t just a matter of learning something new. It’s a complete reorientation. And not everyone wants to turn.”

-The Allegory of the Cave from The Republic, by Plato (Modernized)-