The Complex Brain Hypothesis: Resolving the Entropy-Content Conundrum in Minimal Phenomenal Experience
Jonas Mago, Edmundo Lopez-sola, Jakub Vohryzek, Michael Lifshitz, Robin Carhart-Harris, Karl Friston, Shamil Chandaria
arXiv (Cornell University) May 15, 2026 Peer reviewed DOI: 10.48550/arxiv.2605.16146 via OpenAlex
Summary
Minimal Phenomenal Experiences (MPEs) maintain wakefulness but have low or absent phenomenal content, while high-content psychedelic experiences (HCPEs) are rich in content. Neuroimaging studies suggest both MPEs and HCPEs show increased brain entropy, creating a paradox for the Entropic Brain Hypothesis (EBH). The Complex Brain Hypothesis (CBH) is proposed to better explain these states, indicating that experience richness is more accurately represented by complexity rather than entropy, with implications for understanding consciousness.
Study at a glance
| Key finding | The Complex Brain Hypothesis proposes that richness of experience differentiating MPEs from HCPEs is better indexed by complexity than by entropy. |
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Abstract
Minimal Phenomenal Experiences (MPEs) are states of consciousness in which wakefulness is preserved but phenomenal content is low or absent. The Entropic Brain Hypothesis (EBH) is a model of conscious processes that regards the entropy of spontaneous brain activity as a marker of 'phenomenal richness', exemplified by high-content psychedelic experiences (HCPEs). Yet recent human neuroimaging studies of MPEs induced by meditation -- and possibly 5-MeO-DMT -- suggest that these states, defined by their phenomenological simplicity, also show signs of increased neurophysiological entropy. This presents a conundrum for the EBH: brain entropy is elevated with increased and decreased richness of the phenomenal experience. Here, we put forward the Complex Brain Hypothesis (CBH), which proposes that the richness of experience differentiating MPEs from HCPEs is better indexed by complexity than by entropy. We argue that brain complexity is modulated by the grain of inference through which the brain resolves uncertainty: some HCPEs exemplify a fine-grained regime, in which loosened constraints amplify fluctuations into proliferating content, whereas some MPEs exemplify a coarse-grained regime, in which a simpler model dissolves variety into an experience of 'contentless' awareness. Both regimes can be associated with elevated brain entropy, but they diverge in phenomenology and perturbational signatures. By resolving the entropy-content conundrum, the CBH refines the EBH and highlights MPEs as an important test case for computational theories of consciousness.