The entropic brain today

The entropic brain hypothesis, introduced in 2014 and revised in 2018, proposes that along a dimension of the size of phenomenal consciousness, expansive states—such as expert meditation, psychedelic drug states, and near-death-like experiences—reliably exhibit increased brain entropy, whereas states of reduced or no consciousness—including deep sleep, anesthesia, and disorders of consciousness—show low brain entropy. The hypothesis demonstrates convergent, correlative, predictive, discriminative, and external validity. For example, increased brain entropy under psilocybin predicts improved wellbeing one month later. Changes in brain entropy selectively index the breadth of subjective experience rather than arousal. An entropy-related function is also applied in generative artificial intelligence. The entropic brain is a useful model of conscious states.

Study at a glance

Abstract

Introduced in 2014 and revised in 2018, the entropic brain hypothesis has accrued a wealth of supportive evidence. The hypothesis states that-along a dimension of the size of phenomenal consciousness-expansive states reliably exhibit increased brain entropy whereas the inverse applies for states of no or reduced consciousness. Examples of expansive states include expert meditation, flicker light stimulation, near-death-like experiences, atypical breathing, rapid-eye-movement sleep, the pre-ictal aura, unmedicated early psychosis and psychedelic drug states. Examples of states of no or reduced consciousness with low brain entropy, include disorders of consciousness, deep sleep, the anesthetized state, seizure, post-stroke, ageing, cognitive impairment, and neurodegenerative illness. It is shown that the entropic brain has convergent, correlative, predictive, discriminative and external validity. Regarding its predictive validity, increased brain entropy under psilocybin (in a supportive context) predicts subsequent improvements in mental health (improved wellbeing 1-month post-dose). Regarding its discriminative validity, changes in brain entropy selectively index the breadth of subjective experience versus alternative dimensions, such as arousal. Regarding portability/external validity, an entropy-related function is applied in generative artificial intelligence. In conclusion, the entropic brain is a useful model of conscious states.