The Republic (Book VII)

Ten books asking what justice is; the seventh opens with the most durable image in Western philosophy. Prisoners chained since childhood face a wall; behind them a parapet, a fire, and carriers holding up cutout figures whose shadows are the prisoners' entire world (514a–515c). One is freed, turned around, dragged up the rough steep way, and learns to see in the order the eyes can bear — shadows, reflections, things, the night sky, and last the sun (515e–516b). Then he goes back down, half-blind in the dark, to sit again among those who never left (516e–517a). Just before it, the sentence this bench descends from: the Good, like the sun, is epekeina tes ousias — beyond being (509b). Plotinus built the One on those two words, and the Arabic channel carried the One to the doorstep of Ein Sof.