Physicalism is Unsupported by Similarities Between Drugs and Near-Death Experiences
Image credits belong to: Piron Guillaume (@gpiron) | Unsplash Photo Community
2 Corinthians 5:8-9’s words about being “absent from the body and present with the Lord” tells me that, one day, I will draw my last breath and leave behind a shell of my existence.
Who has not encountered the topic of near-death experiences at least once in their lifetime? Since our bodies will die someday, this is the go-to topic for those who are asking, “Is there an afterlife? And will getting there be smooth-sailing or a hellish ride?”
What comes to mind when you hear the words “near-death experience”? Do you feel curiosity, indifference, or disgust when you encounter someone’s story about their close brush with death that involved visions of God, unearthly entities, deceased loved ones, and more?
Before moving on, let me quote the definition for near-death experiences according to The University of Virginia School of Medicine’s Division of Perceptual Studies:
“Near-death experiences (NDEs) are intensely vivid and often life-transforming experiences, many of which occur under extreme physiological conditions such as trauma, ceasing of brain activity, deep general anesthesia or cardiac arrest in which no awareness or sensory experiences should be possible according to the prevailing views in neuroscience.”
The non-spiritual physicalist/naturalist view in neuroscience is said to be the “prevailing” one. In a separate blog post, we can debate whether or not that majority is continuing its predominance or making room for alternative perspectives. For now, the point is this: physicalism and naturalism imply that “awareness or sensory experiences” should be diminishing during brain-damaging situations and almost absent during life-ending conditions. But NDEs demonstrate something opposite to that, in which everything that is seen, heard, and felt becomes more vivid and intense.
How can that happen if the brain is shutting down?
Image credits belong to: National Cancer Institute (@nci) | Unsplash Photo Community
A Specific Doctor of My Interest
I want to focus on Doctor Bruce Greyson, M.D., who is Carlson Professor Emeritus of Psychiatry & Neurobehavioral Sciences, and Former Director of Division of Perceptual Studies. He was involved with an international group of researchers, who published in 2019 on the topic of phenomenological characteristics shared between psychedelic experiences and NDEs. The title of that report is Neurochemical Models of Near-Death Experiences: A Large-Scale Study Based on the Semantic Similarity of Written Reports, which I intend to discuss throughout most of this blog post.
Doctor Greyson spent a considerable amount of time working with patients in medical settings and is the author of a book called After: A Doctor Explores What Near-Death Experiences Reveal about Life and Beyond. I once thought that the physicalist/naturalistic perspective was the most evidence-based case winning in the debate arena, until I started reading Greyson’s book and realized that the evidence does not give physicalism/naturalism a slam dunk on this issue. There are other professionals in medical specialties similar to Greyson’s who also express that this is not an open-and-shut case.
Image credits belong to: UX Indonesia (@uxindo) | Unsplash Photo Community
So, let’s get on with it!
The abstract from the scientific report states:
"Anecdotal accounts of the similarity between NDEs and certain drug-induced altered states of consciousness prompted us to perform a large-scale comparative analysis of these experiences. After assessing the semantic similarity between ≈15,000 reports linked to the use of 165 psychoactive substances and 625 NDE narratives, we determined that the N-methyl-D-aspartate (NMDA) receptor antagonist ketamine consistently resulted in reports most similar to those associated with NDEs.”
The University of Virginia’s Division of Perceptual Studies recruited people who had NDEs. They were given an optional questionnaire in which they could leave their names undisclosed. 625 narratives were gathered, in which the storytellers were asked to recount events from the past. All except 182 of them scored 7 or higher on the NDE scale, which is a measuring tool developed by Doctor Greyson in collaboration with other colleagues and first published in 1983.
The 2019 study included details such as age, gender, racial identity, and other attributes relevant to demographics. Researchers were interested in the factors contributing to loss of consciousness and the intensity of facing imminent death. They used a 3-point Likert scale (−1 unpleasant, 0 neutral, +1 pleasant) when having participants evaluate the hedonic tone of their experiences, which is the intrinsic attraction or aversion associated with the emotion of the experience.
68% of the participants were females who were 31 ± 15 years at the time of their experience. 13% of the cases were due to head injury, 30% were due to anesthesia/drug use, and 10% were due to cardiac arrest. Participants retrospectively evaluated their experiences, in which 27% were found to be “not serious”, 37% were “serious”, and 35% involved loss of vital signs. 82% of the cases were identified as “pleasant,” 8% were identified as “neutral” and 9% were identified as unpleasant.
Stories about the 165 psychoactive substances were taken from the Erowid corpus, which is a “member-supported organization providing access to reliable, non-judgmental information about psychoactive plants, chemicals, and related issues.” The researchers used an “SVD of the term-document matrix” to analyze and organize the NDE narratives together. An SVD (singular value decomposition) is a mathematical tool that simplifies complex data by focusing on the significant dimensions. There was a table with a list of words represented by rows and documents represented by columns. The SVD found the veiled patterns and concepts within the data by looking at the word co-occurrences, and not just frequency of single terms, appearing in each document.
The researchers instantiate that by saying this:
“… the word ‘fear’ could appear frequently in a report of a frightful experience, but also in a report emphasizing absence of fear. However, the different co-occurrence frequencies of ‘fear’ with other words will increase the semantic distance of the reports.”
The first 20 significant numbers (singular values) were taken from the drug-related dataset, based on previous research agreeing with this. Researchers checked if their results would remain solid even after tweaking the numbers later.
Semantic similarities abounded among the narratives of substances in the same category, in contrast to the substances of other categories. “Within-group semantic similarity” abounded among the narratives of the serotonergic psychedelics (impacting mood, emotion, sleep and appetite) and dissociative psychedelics (inducing detachment from self, body, and surroundings). Similarities abounded among those narratives more greatly than the narratives of the antipsychotics and deliriants, or the stimulants and sedatives. Based on people’s writings about the substances, it was difficult to distinguish between the descriptions of some substances, such as serotonergic and dissociative psychedelics and the entactogens that produce feelings of empathy, emotional openness, and connection with others.
Overall, the researchers/authors conclude that the evidence points to NDE reports sharing similarities with dissociative and serotonergic psychedelic experiences.
Ketamine was found to be most similar to NDEs, out of the top 20 substances that were studied. Ketamine is a dissociative that induces disconnection from oneself and one’s surroundings. It is also used as an anesthetic in medical settings to induce unconsciousness, pain relief, and amnesia.
LSD, DMT, psilocybin, ibogaine, ayahuasca, and mescaline were next to follow in the ranking of most to least similar to NDEs. Nitrous oxide, PCP, and methoxetamine, which are also known for inducing dissociation, were next to follow in the ranking.
Color-coding and pie-charts were used to organize and analyze this.
Image credits belong to: Myriam Zilles (@myriamzilles) | Unsplash Photo Community
Why the relationship between dying and psychoactive drugs?
Multiple cultures, especially psychedelic culture, see the relevance between dying and hallucinogenic effects. Unfortunately, the researchers admit that we are lacking the empirical research to elucidate the nature of that relationship. Many obstacles get in the way of researchers isolating death and dying in the laboratory, which means there are obstacles to measuring the same individuals/subjects in multiple sessions under various conditions. Therefore, we have no easy victory in acquiring the fundamental set of phenomenological aspects that are vital to our findings on death and dying in the laboratory. If we are lacking an exact and accurate empirical definition(s) for the links between psychoactive effects and being at death’s door, we should be wondering if such an association is based on whimsical thinking instead of reasonable thinking.
The researchers imply that the time has come for alternative hypotheses to rival against purely reductionistic explanations of NDEs that use only a psychoactive lens. The researchers report that the empirical evidence shows that being at death’s door is “by itself an altered state of consciousness.” Though pharmacological states dealing with ketamine and DMT may intersect with NDE phenomenology, researchers have not yet been able to compare a broader spectrum of substances for the sake of demonstrating a pharmacological mechanism for the NDE-drug intersection and how a person would neuro-physiologically change as a result. Comparisons of people’s stories about their experiences with psychoactive agents are helpful but have limitations and constraints.
Comparing NDEs and psychedelic experiences might enable us to indirectly assess neurochemical models of NDEs. Doctor Rick Strassman’s parsimonious model proposes a link between NDEs and DMT, in which he hypothesized further that DMT is mainly made from the pineal gland that is placed outside the blood-brain barrier and has an abundant supply of serotonin and methyltransferase enzymes that are ingredients for converting tryptamine into DMT. Unfortunately, no substantial results were gained from the efforts to extract DMT from the pineal glands of deceased bodies. Though feelings of “ego-dissolution”, “unitive experience” and “oceanic feeling” were found intersecting between psychedelic experiences and NDEs, specific personality characteristics were also found intersecting with NDE-like DMT experiences, which comports with the observation that both NDEs and psychedelic trips are context-dependent.
That context-dependence implies to me that the use of a psychedelic is not guaranteed to produce an NDE that is totally predictable according to human desire. Maybe it is worth considering that there is a possible deeper relationship between the experience and factors beyond conscious control.
The body’s endogenous DMT at times of stress could have a role related to the (proposed but not experimentally confirmed) neuroprotective effects against cell death in the nervous system due to hypoxia (lack of oxygen supply to the body’s tissues) or oxidative stress (imbalance between antioxidants and reactive oxygen species). It is worth emphasizing that these neuroprotective effects have not been empirically established. In 2018, David E Nichols had already reported that the tiny quantities of DMT in the brain are insufficient for producing psychoactive effects. Therefore, empirical evidence is lacking for the non-spiritual, physicalist explanations that say the brain is hallucinating or inventing falsehoods during NDEs to cope with impending death.
Looking at the conclusion of this study, the researchers use fancy language to admit that the scientific data can neither confirm nor deny the “endogenous ketamine-like neuroprotective agent” as the mechanistic basis for the out-of-body experiences, meeting deceased relatives and spiritual figures, intense feelings of peacefulness and joy, seeing a brilliant light, and other extraordinary features categorized under NDE phenomenology.
To me, this lack of empirical corroboration should diminish people’s confidence in the use of a physicalist/mechanistic explanation to dispel people’s curiosity and hope for an afterlife. The weaponization of mechanistic explanations rivaling against pesky religious believers is perhaps a distraction from what the evidence is actually saying. It is saying that the shared phenomenological characteristics between psychedelic experiences and NDEs could imply therapeutic advantages against death anxiety in the terminally ill.
The researchers end by saying:
“We believe that the development of evidence-based treatments for such anxiety is a cornerstone of a more compassionate approach towards the universal experience of transitioning between life and death.”
Image credits belong to: Aamir Suhail (@aamir_in) | Unsplash Photo Community
Why Involve Spirituality?
I want to emphasize Doctor Bruce Greyson’s non-physicalist perspective on this, which can be heard in a podcast episode I am hyperlinking here for you. Fast forward to 8:00. He clarifies his awareness of the semantic similarities between NDEs and psychedelic substances but admits that the drug interactions with different neurotransmitters in the brain demonstrates, not a single mechanism underlying NDEs, but only how psychedelics mimic NDEs.
People should be unable to see and report things accurately during their out-of-body experiences, if the physicalist understanding of consciousness is true. On the contrary, people have been able to report things accurately, according to one particular story from Doctor Bruce Greyson who has retold this story, almost verbatim, in nearly every interview I have heard from him.
Doctor Bruce Greyson was a new intern at an emergency room with an overdosed female patient who showed no signs of being conscious on the day that he had talked to her roommate in a separate room, roughly 50 yards away. The hot room compelled him to open his white lab coat to get some air, which unintentionally exposed a spaghetti sauce stain he got on his tie from spilling his dinner on himself prior to entering the conversation with the patient’s roommate. The white lab coat was intended to conceal the stain for everyone who saw him at the hospital and was only exposed during the meeting with the roommate. But according to Greyson’s story, the patient became conscious the next day, in which she told him that she saw him conversing with her roommate and saw the spaghetti sauce stain on his tie.
How could she have known these things while being overdosed, unconscious, and nowhere present to view these things with her own eyes?
Perhaps the naturalistic answer is to assume that someone else might have been privy to Greyson’s conversation with the roommate, and later told the patient about it. But for that to be true, it must have happened without Greyson’s knowledge, since he expresses no doubts about having been alone in talking to the roommate. Perhaps other medical staff were assigned to Greyson’s patient along with him, in which they found it necessary to tell the patient that Greyson was talking with her roommate elsewhere. However, the patient specified that she “saw” Greyson talking to her roommate, and mentioned nothing about being informed by anyone else of anything occurring while she was unconscious. If other medical staff talked to the patient, it is unlikely they would mention something so random and trivial. When you awake in a hospital bed, the last thing you want to discuss is a spaghetti sauce stain on someone's tie from the previous night when you were unconscious.
Unless someone can add some missing details to change this picture of Greyson’s situation, I find it parsimonious to conclude that the patient left her body.
According to how Greyson finishes his story, he was a naive young man who did not know how to interpret this event, but it contributed to his career-long path of studying NDEs.
Stay tuned for my later blog posts about Dr. Greyson’s scientific work and non-physicalist perspective on NDEs.
The author of this blog post is Matthew Sabatine, who was born in the United States and raised as a Christian but left the faith in his early twenties. He returned to the faith midway through 2022. Matthew has some experience in the mental health field as a direct support professional, caring for people with intellectual and development disabilities and people who were in long-term residency/rehabilitation programs. Though Matthew has no formal undergraduate or graduate degree, he has experience co-facilitating therapy groups under the supervision of licensed counselors. Matthew currently works in sales/marketing by day and blogs on his free time at night.
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