The Greek metanoia means, literally, a change of the mind — meta (after, beyond) + nous (mind). In the New Testament it becomes the standard word for repentance. But Plato got there first with a picture, and his picture is the one that lodges in the memory.
In Book VII of the Republic (~380 BCE) the prisoners in the cave have spent their lives watching shadows on the wall, taking the shadows for the real. The philosopher’s education is described as periagoge — a turning of the whole soul. Not an adjustment of the eyes. Not an update of beliefs while still facing the wall. A bodily turn, the whole person rotated toward the fire, then the entrance, then the sun itself.
The Turning chapter treats this as the most independent leg for the repentance-operation outside the Abrahamic tradition — a man who never heard a prophet drawing the same mechanism: re-grounding the reference from the created shadow (a counterfeit, authored by the loop of the cave) to the read sun (the external invariant the shadows were always projections of). The periagoge is not a feeling of regret; it is a structural reorientation. Plato’s cave and the prophets’ shuv — “turn, and live” — describe the same move, from different starting positions, for the same reason: a shadow cannot be a ground.
Sources. Greek metanoia (μετάνοια, “change of mind”), the NT word for repentance (e.g. Mark 1:15); Plato, Republic VII (~380 BCE) — the cave and periagoge, the turning of the whole soul. Search: metanoia repentance Greek meaning; Plato Republic cave periagoge turning of the soul.
Appears in: The Turning, or the Move You Are Always Free to Make Again · The One Thing I Will Not Name