Mystical experience in the Bayesian brain

Mystical experiences, among the most profound human experiences, may arise from a specific neurocognitive state described by the REBUS hypothesis, originally developed to explain how psychedelics alter brain function. During a mystical experience, the brain reduces the influence of its high-level predictions while increasing the weight of sensory input. This shift explains key features: heightened sensory awareness produces a sense of deep knowing (noetic quality), while relaxed prior beliefs lead to feelings of oneness, altered time and space perception, ineffability, and positive mood. The account is conceptual and speculative but aligns with other models suggesting mystical experience involves maximal uncertainty or breakdown of attention.

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Abstract

Abstract Mystical experiences are among the most extraordinary and meaningful experiences one can have. While such experiences have been studied for more than a century, it is still an open question how the brain can produce them. The present paper provides a possible answer by examining mystical experience from the lens of the REBUS hypothesis—a theory that explains the neurocognitive mechanisms of psychedelics in the Bayesian brain. Since psychedelics have consistently been shown to induce mystical experiences, the REBUS hypothesis implicitly suggests that it can also shed light on the underlying mechanisms of mystical experiences. The resulting account holds that during a mystical experience, the brain’s constant process of prediction error minimization is characterized by a decreased influence of high-level predictions and, simultaneously, an increased influence of sensory input. The latter can be related to the noetic quality of mystical experiences; the former to the experience of oneness, altered perception of time and space, ineffability, and deeply felt positive mood during/after a mystical experience. While the paper’s account is developed on a conceptual basis and thus remains speculative, it is compatible with other models of mystical experience, such as that mystical experience involves maximal uncertainty or a breaking down of attention.