[2] Vajrayana Buddhist Tantras mention the nectar "amrita" (literally "immortal", "deathless") which was drunk during rituals and which is associated in the tradition with 'spiritual intoxication'.
[3] A biography of the scholar Gampopa mentions how one of his teachers stated that "You can obtain Buddhahood: by taking a medicine pill which will make you immortal like the sun and moon.
Walter's study of Indo-Tibetan rasayana, ingestion of these substances were said to "strengthen the yogin and procure the siddhi for him, as well as bringing him to the final goal.
[8]Jacques-Joseph Moreau, who reported his experiments with mental patients and drugs, believed that “the hashish experience was a way to gain insight into mental disease.”[9] The French Poet Baudelaire wrote about the effects of Hashish and Opium in Les Paradis artificiels (1860) and theorized about how they could be used to allow the individual to reach "ideal" states of mind.
[10] Baudelaire's opinion of the drug was generally negative, believing that it weakened and dampened artistic capacities, the personal Will and even the very identity of the hashish eater.
Ludlow wrote that a Marijuana user sought "the soul’s capacity for a broader being, deeper insight, grander views of Beauty, Truth and Good than she now gains through the chinks of her cell.
[16][page needed] Huxley also quotes the philosopher C. D. Broad, which held that the brain and nervous system might act as a reducing valve of all the stimuli in the universe: According to such a theory, each one of us is potentially Mind at Large.
Stanislav Grof is known for his extensive work in LSD psychotherapy and for developing a theory which stated that the psychedelic experience allowed one to relive birth trauma and to explore the depths of the unconscious mind.
Grof defined the last level as "experiences involving an expansion or extension of consciousness beyond the usual ego boundaries and beyond the limitations of time and/or space.
[citation needed] The scientist and philosopher John C. Lilly discussed his experiments with psychedelics and altered states of consciousness in The Center of the Cyclone: An Autobiography of Inner Space and Programming and Metaprogramming in the Human Biocomputer.
The philosophical foundation of this new wave of psychedelic thought was based on the works of Alexander Shulgin, Alex Grey and Terence McKenna.
[20] In this book, Langlitz recounts the findings of his fieldwork following scientists involved in reviving scientific research on psychedelics as well as his own philosophical reflections.
He explains that Aldous Huxley's view expressed in The Doors of Perception—of the brain as a "reducing valve" which when released by the ingestion of a psychedelics produces a "perennial" mystical experience—has been very influential among contemporary psychopharmacologists.
[21] The philosopher Thomas Metzinger has discussed the effects of substances such as LSD, dimethyltryptamine, and mescaline in his Being No One (2003) and those of psilocybin in The Ego Tunnel (2009).
The objection is that psychedelic therapy works by inducing non-naturalistic metaphysical beliefs, and so it is epistemically deficient if one adopts a philosophically naturalistic world-view.
[4] Letheby concludes that the Comforting Delusion Objection fails, and that the epistemic status of psychedelic therapy, given philosophical naturalism, is good.