When you look at a device screen, read these lines and feel the ground beneath your feet, it seems to you that you perceive the world as it really is, that the process of perception works like a video camera: the eyes capture light, transmit a signal to the brain, and an exact copy of the objective world appears on your inner screen.
Neuroscientist and consciousness researcher Anil Seth of the University of Sussex argues that this is a fundamental mistake. According to his research, your brain does not "record" anything. It continuously hallucinates.
In his famous TED talk and in the book "Being You: A New Science of Consciousness," Seth utters a phrase that blew up the scientific community: "We are all constantly hallucinating, including right now. It's just that when our hallucinations agree, we call it reality".
To understand what "controlled hallucination" is and why it is a concept that is absolutely sound from a scientific point of view, we need to look inside the skull.
The brain is a prisoner in a dark room
The brain's main problem is that it has no direct access to the surrounding world. It is locked in a dark, soundproofed skull. It has no eyes or ears — only bundles of wires (nerve fibers) that transmit electrical impulses to it, reflecting changes in the environment.
These sensory signals (visual, auditory, tactile) are meaningless in themselves and full of noise. The brain needs to figure out: what exactly in the external world caused this electrical noise?
The brain as a prediction machine (predictive coding)
Neuroscientists used to believe that the brain works "bottom-up": passively gathering details from the sense organs and assembling a coherent picture from them. Seth and modern cognitive neuroscience prove the opposite. The brain works "top-down."
It does not wait for incoming data to start thinking. The brain constantly builds predictions (guesses) about what should happen in the next millisecond, relying on past experience and context.
- The sense organs transmit only "prediction errors" — that is, a signal that reality did not match what the brain expected.
- The brain instantly corrects its internal model of the world so as to err less next time.
Thus, what we are aware of as "perception" is not a reading of reality, but the brain's best guess about what caused that reality.
The difference between perception and hallucination
Here lies the essence of Seth's concept.
When you take psychedelics, are in a state of psychosis, or simply dream, your brain generates perception without relying on incoming sensory signals. The brain's predictions override prediction errors. This is the classic uncontrolled hallucination.
But what happens when you are awake and sober? The brain still generates predictions from within. But now these predictions are tightly bound to external sensory signals. If the brain "thinks" there is a tiger in front of it, while the optic nerves are transmitting a signal about a chair, the brain instantly updates its hallucination, turning the tiger into a chair.
Perception is a hallucination that is constantly checked and kept in check by sensory signals from the external world. That is precisely why Seth calls our everyday perception "controlled hallucination".
The illusion of the "Self": the beast machine
The most surprising thing about Seth's theory is that it concerns not only the external world but also our inner "Self."
Our sense of our own body, emotions, and continuous personality is also a controlled hallucination. The brain continuously predicts the state of internal organs (heartbeat, breathing, blood sugar level). This is called interoception. The way the brain interprets these internal signals for the sake of the organism's survival gives rise to our emotions, mood, and the basic feeling of "I exist."
Seth calls this the "Beast Machine" theory. We are biological animals, and our consciousness evolved not to cognize the objective truth of the cosmos, but to effectively regulate the body and keep it from dying.
Why does this matter?
The concept of controlled hallucination changes our view of the world and of ourselves for three reasons:
1. Humility. There is no objective reality accessible to our perception. Each of us lives in our own unique simulation, created by neural connections. What you see is literally different from what I see (which is precisely why optical illusions and color blindness exist).
2. Understanding mental illness. Schizophrenia, anxiety disorders, or depression are not simply a "breakdown" of the brain. They are a failure in the mechanism of prediction, when the brain's internal hallucinations lose touch with reality or generate frightening forecasts about the body and the world.
3. The beauty of subjective experience. If consciousness is not merely a mirror of nature but an active creation of the brain, then the human mind acquires a truly magical nature. We are not merely observers of the Universe — we are its co-creators, generating meaning in the darkness of the skull.
To sum up in the words of Anil Seth himself: "Reality is just a hallucination we have all agreed on". And realizing this fact makes us not less connected to the world, but, on the contrary, far more attuned to how the perception of other people is structured.
Sources:
- Anil Seth, "Being You: A New Science of Consciousness" (Being You: A New Science of Consciousness, 2021).
- Anil Seth's TED Talk: "Your brain hallucinates your conscious reality" (2017).
