“They see only their own shadows, or the shadows of one another, which the fire throws on the opposite wall of the cave.”Plato · The Republic
Shadows in the cave are taken as reality, yet truth lies beyond them
Plato imagines people chained in a dark cave since childhood, seeing only shadows cast by a fire behind them. For them, the shadows are the only reality they know. If one escaped outside into sunlight, they would be blinded at first, then realize how limited their old world truly was.
Why it matters The allegory is still used today to talk about online information bubbles.