Let me speak a parable. Humanity--ourselves--are as people dwelling ever bound and fettered in a twilit cave, with our backs to the light. Behind us is a parapet, and beyond the parapet a fire; all that we see is the shadows thrown on the wall that faces us by figures passing along the parapet behind us; all we hear is the echo of their voices. Now, if some of us are turned round to face the light and look on the real figures, they will be dazzled at first, and much more if they are taken out into the light, and up to face the sun himself; but presently they will see perfectly, and have all the joy thereof. Now send them back into the cave, and they will be apparently much blinder than the folk who have been there all the time, and their talk of what they have seen will be taken for the babbling of fools, or worse. Small wonder that those who have beheld the light have but little mind to return to the twilight cave which is the common world. But remember--everyone in the cave possesses the faculty of sight if only his eyes be turned to the light. Loose the fetters of carnal desires which hold him with his back to the light, and every man _may_ be converted and live. So we must select those who are most capable of facing the light, and see to it that they return to the cave, to give the cave-dwellers the benefit of their knowledge. And if this be for them a hardship, we must bear in mind as before, that the good of the whole is what matters, not whether one or another may suffer hardship for the sake of the whole. How, then, shall we train them to the passage from darkness to light? For this, our education in music and gymnastic is wholly inadequate. We must proceed first to the science of numbers, then of geometry, then of astronomy. And after astronomy, there is the sister science of abstract harmonics--not of audible sounds. All of which are but the prelude to the ultimate supreme science of dialectic, which carries the intelligence to the contemplation of the idea of the good, the ultimate goal. And here to attempt further explanation would be vanity. This is the science of the pure reason, the coping-stone of knowledge. We saw long ago that our rulers must possess every endowment of mind and body, all cultivated to the highest degree. From the select we must again select, at twenty, those who are most fit for the next ten years' course of education; and from them, at thirty, we shall choose those who can, with confidence, be taken to face the light; who have been tested and found absolutely steadfast, not shaken by having got beyond the conventional view of things. We will give them five or six years of philosophy; then fifteen years of responsible office in the state; and at fifty they shall return to philosophy, subject to the call upon them to take up the duties of rulership and of educating their successors. _VI.--Of State Types and Individual Types_