Perception is a controlled guess

The brain never receives a finished world. It receives changing signals and must infer what probably caused them. Anil Seth describes perception as a “controlled hallucination”: prior expectations generate guesses, sensory evidence corrects them, and the best-fitting interpretation becomes experience. Optical illusions are useful because they expose the normally invisible negotiation.

The phrase does not mean reality is imaginary or that every interpretation is equally valid. Prediction is constrained by signals and successful action; a guess that repeatedly collides with the world loses. The bounded claim is that seeing is active inference. Most of the time the machinery disappears because its predictions are good enough, leaving only the compelling impression of direct access.