So, some guys were out hiking and they found a cave, and because they were stupid they went inside to explore it. While they were inside, though, a bunch of rocks fell and hit them in the head, so they got knocked unconscious and trapped against a wall. When they woke up, they couldn’t remember ever having lived outside the cave, and they couldn’t move because they were trapped by the rocks. All they could do was stare straight ahead at the wall across from them. Now, there was an old hobo who lived in the cave, and he was sort of crazy, and liked puppets. So at night he would have puppet shows by his camp fire in the cave, and the shadows from puppets got cast onto the wall in front of the trapped hikers. Because these stupid guys couldn’t remember anything else, they assumed that the whole world was just shadows moving along the wall, and so they thought that the shadow-horse was what a horse was, and that a shadow tractor was what a tractor was, and so on.
This went on for a while, and the hobo, being crazy, never noticed the guys trapped in his cave or said anything to them. Now, eventually, the rock that was pinning one of the guys in place shifted, and suddenly he realized he could get up and move around. Everything hurt and he was really stiff, but after he got over the pain he struggled to his feet, and discovered the fire and the puppets sitting on the ground behind him. After spending so long staring at shadows on a wall, he thought the little camp fire was blindingly bright, and concluded that the light of the fire must be TRUE light, since it was what illuminated all the shadows on the wall, and even now illuminated the horse and tractor puppets on the floor. He also took the puppets for the real things, figuring that a tractor puppet was a real tractor and so on. And he decided that the universe, which he used to think was just a wall, was much bigger than he thought, since it was a whole cave.
While he was sitting there, the free hiker tried explaining to his trapped friends that there was a whole cave and a fire, and not just one wall with shadows. But they thought he was just making fun of them and trying to trick them into believing something stupid, since they didn’t understand how there could be anything more than what they saw with their own eyes. So the free hiker gave up on them and sat staring into the fire for a while.
Now, after a while the hobo came back to his cave from his latest round of chicken-thievery, and found the freed hiker sitting by the fire. The hiker greeted him and started praising his wonderful camp fire and the amazing horse and tractor puppets. The hobo agreed with him and, because he was crazy, didn’t challenge the hiker when he was talking about the puppets as if they were real. When they were finished talking, the hiker fell asleep, and in his sleep he rolled around a bit, so that his back was turned away from the fire and toward the entrance of the cave. Up to this point he hadn’t noticed the entrance to the cave, because it was evening and he’d been too interested in the fire. But when he woke up, the moon had come up and there was a glow of light in front of him from outside. Curious, he left the fire and walked toward the glow.
At first, the glow seemed faint and distant compared to the flickering light of the fire, but as he got closer to the mouth of the cave, the light was stronger and clearer, until at last he stepped outside. There was a small pond in front of the cave, and he stepped up to the edge and saw all the stars and the bright moon reflected in the pond. For a second he stared at the reflected light and said “Aha! This has to be the REAL light. The campfire was just an imitation.” And he saw an abandoned tractor near by in the dark, and realized that he had been mistaken about the puppets. Then he fell asleep again.
Finally, morning came, and the sunlight, and the hiker woke up again. Then he saw the tractor illuminated by the sunlight, and saw the brightness of the world, and again realized how mistaken he had been: about the moon, and about the campfire, and about the shadows on the wall. He understood that the world was much bigger and better than he’d thought, and so he wanted to return to the cave and help his friends who were still trapped staring at shadows on a wall.
When he went back inside, though, he had trouble seeing and finding his way around, since his eyes were used to the sunlight. And when he finally found his friends, he tripped over a rock and fell. They laughed at him and made fun of him. So then he tried to explain about the sun and the outside world, but they didn’t understand because all they knew were shadows in the cave, and again they thought he was either crazy or trying to make fools of them. So they refused to let him move the rocks off of them, and insisted on staying where they were. Frustrated, the freed hiker got up and walked away, unsure of how he could get his friends to come outside and see the light before they starved to death in the cave.