From Book VII of Plato's Republic.
Part I: Imprisonment
Imagine a cave…
Inside this cave were prisoners, who had been chained—since birth—with their backs to the cave's entrance. They couldn't see what was behind them. They knew nothing of the outside world and they had never seen anything except for the wall before them.
Behind these prisoners, there was a bonfire. Any creature or item that appeared between the prisoners and the fire cast a blurry shadow on the wall, which the prisoners saw. These shadows were all that the prisoners knew in their lives and they studied these with great care and enthusiasm—firm in the belief that these were the real objects themselves and not mere shadows.
As it happened, there was also a walkway that ran behind the prisoners—between them and the fire. Travellers and folks carrying objects, too, projected shadows on the wall. The prisoners passionately discussed and debated the true nature of what they saw—ignorant of the fact that these were mere shadows and that the light of truth laid behind them.
The prisoners lived their entire lives in the shadows, discussed and debated shadows, observed shadows, opined on shadows and believed in shadows. They knew nothing of the outside world—they couldn't even begin to imagine it. The world of shadows and ignorance defined their existence. It was all they'd ever known.
Part II: Liberation
One day, one of the prisoners was freed…
Slowly, this mysteriously freed prisoner turned around for the first time in his life. He was overwhelmed by intense pain in his eyes and the accompanying horror as the unknown sight of the bonfire greeted him. He could not look straight into the light as his eyes could not adjust in time from the years of looking at nothing but shadows. He was gripped by incomprehension and fear.
Gradually, however, his eyes made the adjustment to the light. He was still fearful, but he was becoming curious. Illuminated by the fire, he began to explore the world beyond the shadows. The prisoner was in awe and wonder as he beheld the cave and it's glory in the light. Eventually, he could even look straight into the fire. As his eyes soaked in the sights around him, he noticed—off in the distance—a fainter light. It was the entrance of the cave.
The prisoner had never known anything but the wall, let alone the cave. He could not begin to imagine an “outside.” Driven by curiosity and his love for knowledge, he stood up and walked—clumsily, at first, but with determination. As he ambled towards the fainter light, it grew stronger and brighter until he had to shut his eyes. He pressed onwards.
Tears streamed down his cheeks. The stinging pain of the light did not bother him. An intense shiver overtook his entire being. His heart sank but it was not heavy. There were butterflies in his stomach as the prisoner beheld the rolling green meadows and the magnificent blue sky. A warm and indescribable joy washed over him.
A radiant life-giving orb in the sky illuminated all. It was the source—the truth. The prisoner knew this despite being unable to look directly at it.
Part III: Return
The world outside—the world of light and truth—was beautiful…
But empathy and compassion reminded the enlightened prisoner of his companions back in the cave, still bound by chains. He remembered the many years of fervent, passionate debating and the vicious, endless arguments over mere shadows. He bore no resentment towards his fellow prisoners—no condescension—only empathy and compassion.
He began making his way back into the darkness of the cave. Having become accustomed to light, his movement in the dark was once again clumsy. To all who saw him, he appeared as if he'd lost his mind.
When he at last sat amongst his fellow prisoners, he began to regale them with the stories of all he had seen—of the fire and the shadows it projected; of the cave and the world beyond it; of rolling meadows, the blue sky and the magnificent sun. He was mad and they were all sure of it. They rejected him vehemently and saw him as a threat.
The prisoners grew more and more intolerant—even violent. Like a mad stampeding herd, they irrationally reached out and crushed anyone who challenged their shadowy worldview. Order was restored in the cave.
Inspired by the life and death of his mentor Socrates, Plato wrote this allegory in his Republic—a Socratic dialogue on justice.
The Allegory of the Cave explored the impact and importance of education—specifically, what has today come to be called “liberal education”—on human nature.
Unlike “professional” education, which cultivated skills that a pupil can sell, liberal education sought to liberate and enlighten the students' minds. It rigorously trained students to critically examine everything—including one's own psyche—and seek the light of truth with honesty and humility.
Liberal education encouraged students to cultivate a sense of wonder and a “love of knowledge and wisdom”—what the ancient Greeks called Philo-Sophia, the origin of our word philosophy.
The purpose of education—as far as old-school liberal education was concerned—was never about helping students find jobs. It promised a prize of far greater value: liberty.
Education wasn't just a framed diploma from a university, nor was it merely a set of facts or doctrines that one memorized, abode by or believed in. It was a critical, careful and humble way of seeing and thinking.
This involved the Socratic method of hypothesis elimination, first applied by Socrates over 2,400 years ago to moral and ethical questions. Today, it is the foundation of modern science and research in all fields of knowledge.
“Only the educated are free,” the Stoic philosopher Epictetus once said. Many celebrated historical figures—like the self-taught Benjamin Franklin, President Lincoln and Confucius—keenly understood and appreciated this.