Huxley held that psychedelic drugs open a 'Reducing Valve' in the brain and nervous system that ordinarily inhibits 'Mind at Large' from reaching the conscious mind.
He observed that everyday objects lose their functionality, and suddenly exist "as such"; space and dimension become irrelevant, with perceptions seemingly being enlarged, and at times even overwhelming.
'In The Doors of Perception, Huxley cites a 1949 paper by Cambridge Philosopher C. D. Broad ('The Relevance of Psychical Research to Philosophy') thus:[5] Reflecting on my experience, I find myself agreeing with the eminent Cambridge philosopher, Dr. C. D. Broad: ‘that we should do well to consider much more seriously than we have hitherto been inclined to do the type of theory which Bergson put forward in connection with memory and sense-perception.
To make biological survival possible, Mind at Large has to be funnelled through the reducing valve of the brain and nervous system.
What comes out at the other end is a measly trickle of the kind of consciousness which will help us to stay alive on the surface of this particular planet.In 2023, a research paper entitled Nested hermeneutics: Mind at Large as a curated trope of psychedelic experience, noted that this passage—as quoted by Huxley—contains two significant omissions and one alteration from Broad's careful summary of Henri Bergson's philosophy on perception and memory.
The Doors of Perception beyond its philosophical speculation was a seminal psychedelic work detailing a diary of Huxley's experiences during the day when Osmond visited him in Los Angeles during May 1953 to administer 0.4 g of mescaline.
In the excerpts, Hagerty connects the research of neuroscientist Andrew Newberg on religious experiences in Catholic nuns and Buddhist monks to Huxley's concept of Mind at Large.