The incoming sensory barrage is met by a cascade of top-down predictions, with prediction error signals streaming upward to stimulate ever better predictions and elicit new actions. This rolling process gives rise to an approximation to Bayesian inference, a GoodEnough Bayesianism in which the brain settles and resettles on its evolving best guess about the causes of its sensory environment, and a vivid perceptual world—a controlled hallucination—is brought into being.
