The Short Version
If you read nothing else, read this.
For a century, a striking idea has circulated: that humanity's oldest religions were not born from abstract philosophy, but from direct, altered-state experiences, visions induced by sacred plants and fungi. This month's study maps who has argued it, and how far the evidence actually carries.
The honest picture is a gradient, not a verdict. It is well-documented that real ancient religions used mind-altering sacraments, soma in the Vedas, the rites of Eleusis. It is arguable that these experiences shaped religion's core ideas of death, rebirth, and the divine. And it is near-baseless that mushrooms literally built the human brain, the famous claim that made the theory popular.
The takeaway worth carrying: you don't need the wildest version to be true. Modern neuroscience has now confirmed the modest, powerful core, that these states reliably produce genuine, life-altering spiritual experience. The map below grades each source by how much weight it can bear: from rigorous evidence, to respectable foundation, to inspired speculation best read with a knife.
How each source is graded
Rigorous, evidence & method
Respectable, foundational frame
Speculative, read with a knife
I.The Provocation
Where most people start. Brilliant, sweeping, and overconfident. Read it for the question, not the proof.
Terence McKennaFood of the Gods (1992)
SpeculativeThe famous one. Argues psychoactive plants shaped human evolution, religion, and our broken bond with nature. Strong as cultural history (documented sacraments); near-zero evidence for its headline "Stoned Ape" claim that mushrooms birthed human consciousness. Take the history seriously, the hominid theory as a campfire story.
II.The Rigorous Core
The real scholarship McKenna stood on, and the best modern attempt at hard evidence.
R. Gordon WassonSoma & The Road to Eleusis
RespectableThe ethnomycologist who did the actual work. Soma (1968) makes the case that the Vedic "drink of the gods" was a mushroom; The Road to Eleusis (1978), co-written with Albert Hofmann, the discoverer of LSD, argues the Greek Mysteries ran on an ergot brew. The serious lineage, not blog mysticism.
Brian MurareskuThe Immortality Key (2020)
RigorousThe most important recent book in the field, and the one closest to the Eden-mushroom thread. A lawyer-scholar spends 12 years chasing physical evidence, archaeochemical residue in ancient ritual vessels, for psychedelic sacraments in Greek and early Christian rite. Overreaches at the edges, but it's the disciplined version of McKenna's question.
Carl RuckClassical scholarship on entheogens
RespectableBoston University classicist who coined the word "entheogen." Academically embattled for it, but his work on Greek and Christian sacraments is genuine classical scholarship. The bridge between Wasson's mycology and the textual evidence.
III.The Foundations
The university-taught classics on mystical experience itself. Older, deeper, still standing.
Mircea EliadeShamanism: Archaic Techniques of Ecstasy
RespectableThe canonical scholarly study of how altered states, drug-induced or not, underpin religious experience worldwide. McKenna leaned on Eliade; Eliade is on the syllabus.
William JamesThe Varieties of Religious Experience (1902)
RespectableThe bedrock text treating mystical states as real psychological phenomena worth studying. James experimented with nitrous oxide himself. A century old and still the starting line.
Aldous HuxleyThe Doors of Perception (1954)
RespectableThe elegant first-person bridge between psychedelics and mysticism. Literary rather than evidentiary, but it set the language everyone after him used.
IV.Where the Real Data Lives
Modern neuroscience. The strongest living evidence that altered states produce genuine spiritual experience. Measurable, repeatable, peer-reviewed.
Roland GriffithsJohns Hopkins psilocybin studies
RigorousClinical trials showing psilocybin reliably produces experiences participants rate among the most meaningful of their entire lives, often indistinguishable from classic mystical experience. The hard proof that the McKenna-adjacent claim is true, just in the present rather than prehistory.
Robin Carhart-HarrisThe "Entropic Brain" / REBUS model
RigorousThe leading neuroscientific account of how psychedelics dissolve the brain's ordinary hierarchies, giving a real mechanism for the "ego dissolution" mystics have described for millennia.
The One Thing to Carry
The field splits in two: speculation about the deep past (McKenna, hard to verify) and measurement of the present (Griffiths, Carhart-Harris, well-evidenced).
You don't need the Stoned Ape to be true. You only need "altered states produce real, reportable spiritual experience", and that is now lab-confirmed. Anchor the wonder in the verifiable end.