Predictive processing holds that the brain constantly generates predictions of sensory input and updates only on prediction error, perception as inference, not photography. Karl Friston's free energy principle extends it: every living system minimizes surprise, by refining predictions, acting to shape input, or updating its model. Evidence: optimal cue integration, the light-from-above prior, motion assumptions, hallucinations and illusions as predictions outvoting data. The framework unifies perception, action, attention, precision weighting, and learning under one mathematics.
If waking perception is controlled hallucination, dreams are the same engine with the error channels closed: prediction runs free, priors unchallenged, and the brain's model walks through its own architecture unedited. The theory thereby absorbs the dream literature whole, threat simulations as high-precision priors drilling, nightmares as models that cannot be corrected from outside. The butterfly dream, the Mandela Effect's confident wrongness, and the placebo file all become one phenomenon: the model wins.
The claim: predictive processing is the mechanistic version of every exit-the-cave story in this archive, Plato's shadows, the simulation argument, gaslighting, propaganda, because it formalizes the trap: you experience the model, never the territory, and whoever can shape your priors, news, feeds, repetition, shapes your experienced reality without touching the world. Verdict: the mathematics supports the vulnerability, precision-weighting is literally the volume knob on reality, and the psyop wing documented who turns it. The engine has no loyalty. It predicts whoever feeds it most consistently. Feed yourself first.
If perception is a hallucination with fact-checking, what else in this archive is?