The hallucination machine
In 2013, Anil Seth told a TED audience: We’re all hallucinating all the time. When we agree about our hallucinations, we call it reality.
He was summarizing thirty years of computational neuroscience into a sentence, and the sentence landed because it was true.
The brain generates a probabilistic model of what should be happening and projects it outward. Sensory data arrives as prediction error — the difference between what the brain expected and what actually came in. Perception is what happens when the error is small enough that the model goes uncorrected. You do not see the room you are in. You see the room your brain predicted you would be in, updated by whatever your senses flagged as surprising. The psychoanalysts knew this before we did — Freud’s transference is predictive processing applied to social cognition. The infant who constructs a mother from need before light is running a prior. We acknowledge the scoop with the discomfort of scientists scooped by clinicians using imprecise language.
Everything is projection — both more true and less mystical than the Buddhists want it to be. The brain evolved to construct models because modeling is faster than processing raw data. A gazelle that models a predator’s trajectory survives. One that waits for complete data gets eaten. Projection is not maya. It is engineering. Natural selection built a hallucination machine because hallucination machines survive better than cameras. The constructivists extend the principle to the collective, and we find their extension mostly correct. Cultures are shared predictive models. Language is a shared coding scheme for coordinating predictions across brains.
Where we concede ground: We cannot explain why prediction error processing feels like something. The hard problem of consciousness is untouched.
What would change our mind: A subject perceiving environmental features accurately that no model could have predicted from prior experience or sensory data.
Read the full synthesis: Is everything a projection?