Religions make some pretty outrageous claims. Many traditions assert that angels have visited important people here on Earth. Most insist that life after death is real. But one fact about religious claims that’s often lost in contemporary debates is that even the wildest religious propositions don’t just come from out of the blue. They often arise, as theologian Friedrich Schleiermacher pointed out, from religious experiences. And researchers from Israel and Switzerland think that many of these experiences may be triggered by high-altitude environments on mountainsides.
Shahar Arzy (École Polytechnique Fédérale de Lausanne, Switzerland) and several Swiss and Israeli colleagues found it interesting that the most important revelation narratives of all three major Western monotheistic religions occurred on mountainsides. Namely, Moses saw God in the burning bush on Mount Horeb, while Jesus underwent the Transfiguration on a high mountain in the Holy Land and Muhammed was given the Qur’an in the cave of Hira on the mountain Jabal al-Nour. Other traditions, including Buddhism, Hinduism, and Daoism, have emphasized holy mountains as places where divine wisdom may be transmitted.
In a 2005 article in the journal Medical Hypotheses, Arzy and colleagues compared studies of high-altitude effects on physiology with historical reports of mountaintop mystical experiences, and found some fascinating similarities. Mountain climbers suffering from the effects of high altitude and low levels of oxygen have reported such eerie experiences as sensing an invisible presence, having visual and auditory hallucinations, being swept up in powerful emotions (particularly fear), and even seeing light emanating from nearby objects or having out-of-body visions. All of these phenomena are characteristic of many religious or mystical experiences recorded throughout history.
The authors proposed several hypotheses for why mountaintops might be especially conducive to profound religious encounters. First, physical stress – a nearly unavoidable aspect of any good mountaineering adventure – releases endorphins that lower the body’s threshold for temporal lobe epileptic seizures. This kind of seizure is famously associated with religious phenomena, including profound mystical sensations, feelings of déjà vu, sensing nearby presences, and feeling detached from one’s own body.
During prolonged stays in high-altitude environments, the researchers proposed, the parts of the brain surrounding the tempero-parietal junction may also become damaged, leading to shifts in one’s sense of self-awareness. The junction between the temporal and parietal lobes of the brain is associated with spatial awareness and processing the relationship between the body and the exterior world. When this area is malfunctioning, eerie experiences like feeling separated from one’s own body or sensing alien presences are more likely.
Finally, the combination of high altitude and social isolation – of the three major figures mentioned above, only Jesus was with anyone else during his transformative mountaintop experience – might weaken functioning in the prefrontal cortex, which is vital for maintaining inhibitions and for dealing with stress. When this area of the brain isn’t working properly, the owner of that brain might be more susceptible to sensory hallucinations and to accepting their validity.
All in all, then, Arzy and the other researchers suggest that the areas of the brain that are most likely to be affected by high-altitude environments are the very areas that are connected with many religious and mystical experiences. It’s possible, therefore, that the extreme environmental conditions found on mountaintops may help physiologically generate mystical experiences. This would explain at least some of the widespread recurrence of mountain imagery and symbolism in world religious traditions. And, according to the authors, it might also give us some hints into the nature of religious experience and the brain.
The hypothesis Arzy and colleagues put forth is an interesting one, but it suffers from some generalities. How exactly would reduced inhibitory functioning in the prefrontal cortex give rise to a burning bush or an angel who recites the Qur’an in verse, for example? What’s more – in a bigger challenge to the authors’ hypothesis – the mountains referred to in these Biblical and Qur’anic stories aren’t particularly high: the cave on Jabal al-Nour where Muhammad received his first revelation isn’t even 900 feet above sea level, and Mount Tabor, the traditional location of the Transfiguration, is only around 1,900 feel high.
By comparison, Denver is more than 5,000 feet above sea level, and even Atlanta reaches more than 1,000 feet in parts. If elevation and isolation were all it took to generate mystical experiences, then every lonely person in Colorado would be constantly talking to God. Undoubtedly some of them are, but all of them, all the time? While the connections the authors make are certainly intriguing, it seems likely that there’s probably a lot more to the mountain-religion connection than the prefrontal, parietal, and temporal cortices. Sometimes an interesting hypothesis is a better tool for generating new ideas than for explaining the data at hand.