Friday, March 01, 2024

Religious Experience in the Brain: Saint Paul's Mystical Visions

                 Michelangelo's "Conversion of Saint Paul," a Fresco in the Sistine Chapel

In my previous post, I might have conveyed the impression that religious experience can be fully explained by ecstatic epilepsy triggered in the anterior insula.  If I did, that's a mistake that I need to correct.  I should have been more emphatic about the disclaimer that I put near the end of the post: "Of course, this does not mean that ecstatic epilepsy is the only source in the brain for religious experience.  There are other ways in which the brain might facilitate human access to the divine (Nelson 2011; Newberg 2018)."  I can illustrate this point by considering the neurobiology of Saint Paul's ecstatic mysticism.

In his classic study of Paul's mysticism--The Mysticism of Paul the Apostle (1931)--Albert Schweitzer briefly mentioned the possibility that Paul's mystical visions could have come from seizures.  Since then, others have suggested that Paul's visions were caused by ecstatic epileptic seizures.  And, as I indicated in my previous post, Fabrienne Picard has identified the anterior insula as the primary brain structure for the sort of ecstatic seizures experienced by Paul.  But in her book on the neurobiology of Paul's ecstatic experiences, Colleen Shantz concluded that "the suggestion that Paul's visions were caused by epileptic seizures should be laid aside or, at the very least, bracketed as an insufficient explanation" (2009: 151).

Although there are a few cases--such as Dostoevsky--where ecstatic epilepsy seems to be crucial for religious experience, these cases are so rare that they cannot explain most religious experience.  Epilepsy itself affects only a small minority (between 4 and 10 per 1,000) of every human population.  And among those with temporal lobe epilepsy, less than 5% have ecstatic experiences.

The rarity of ecstatic epilepsy is evident in the work of Picard.  In one review article, she surveyed a total of 55 individuals who have had ecstatic seizures, based on reports from 1951 to 2015 (Gschwind and Picard 2016).  As I noted in my previous post, Picard's most dramatic evidence for her "anterior insula hypothesis" comes from his treatment of epileptic patients in Geneva, Switzerland.  In treating one patient with ecstatic epilepsy, she found that he could induce ecstatic auras by the electrical stimulation of her anterior insula.  Even more amazing, she found that he could induce ecstatic auras by the electrical stimulation of the anterior in one patient with temporal lobe epilepsy who had never had ecstatic experiences previously.  But then, after reporting these cases, she made a remarkable admission:  "It must be specified that the induction of an ecstatic aura through the stimulation of the dorsal part of the anterior insula is not the rule, as there are many patients in whom stimulations of this region did not give rise to ecstatic experience" (Picard 2023: 1375).  Shouldn't this failure to replicate her findings count as a falsification of her hypothesis?


Picard could support her hypothesis if she could show that people with ecstatic epileptic seizures have religious experiences like those of Paul's mystical visions as reported in the New Testament.  But she fails to do that.

Acts 9:3-9 describes the famous conversion of Paul on the road to Damascus.  Paul had been persecuting the Christians, and he was traveling from Jerusalem to Damascus where he planned to take some Christians as prisoners.  But then he had an amazing experience of conversion:

"As he neared Damascus on his journey, suddenly a light from Heaven flashed around him.  He fell to the ground and heard a voice say to him, 'Saul, Saul, why do you persecute me?'  'Who are you, Lord?' Saul asked.  'I am Jesus, whom you are persecuting,' he replied.  'Now get up and go into the city, and you will be told what you must do.'  The men traveling with Saul stood there speechless; they heard the sound but did not see anyone.  Saul got up from the ground, but when he opened his eyes, he could see nothing.  So, they led him by the hand into Damascus.  For three days, he was blind, and did not eat or drink anything."

In Damascus, a disciple named Ananias had a vision in which the Lord told him that he was to meet Paul, restore his vision, and tell him that he had been chosen to proclaim Jesus to the Gentiles and the Jews.

Later, Paul said he should be considered an apostle of Christ because he had seen and talked with Christ like the original apostles.  Writing to the Corinthian Christians, he even described his experience in ascending into Heaven:

"I must go on boasting.  Although there is nothing to be gained, I will go on to visions and revelations from the Lord.  I know a man in Christ who fourteen years ago was caught up to the third heaven.  Whether it was in the body or out of the body I do not know--God knows.  And I know that this man--whether in the body or apart from the body I do not know, but God knows--was caught up to paradise and heard inexpressible things, things that no one is permitted to tell" (1 Cor. 12:1-4).

Here Paul might have shown the influence of some Jewish mystical traditions.  Some Jewish texts identified "paradise" as the restoration of Eden in Heaven that might be established in the renewed Earth.  There was disagreement about the number of heavens, but the most common view identified three or seven heavens.  The "third heaven" was probably the highest heaven, where God was.

So, if Picard were right about the anterior insula being the prime locus for religious experiences like this, we would predict that people having ecstatic epileptic seizures in the anterior insula would report visions and revelations similar to what Paul reported.  But when we examine the 52 cases of ecstatic seizures surveyed by Gschwind and Picard, and look at the signs of ecstatic experience, we see very little resemblance to what Paul reported (Gschwind and Picard 2016: 4-9).  We see a lot of vague descriptions of a euphoric state such as "sensation of joy," "pleasant butterfly in stomach," "sudden feeling of happiness," "calm euphoria," "feeling union with the whole world," "feeling like orgasm," and "intense feelings of bliss and well-being."  But in these 52 cases, there is only one reference to "heaven," one reference to "paradise," three references to "God," and no references at all to Jesus Christ.  This hardly looks anything like Paul's mystical experiences.


If there is any neurobiological explanation for religious experiences like those of Paul, it must be more complex than simply identifying the posterior insula as the prime mover.  That more complex neurobiological model has been emerging in the research surveyed by people like Shantz (2009) and Andrew Newberg (2018).  In contrast to Picard's attempt to explain religious experience as caused by a brain disorder--temporal lobe epilepsy--Shantz and Newberg see religious experience as made possible by the normal functioning of the brain in response to religious practices that alter the brain.

There have now been over one hundred neuroimaging and physiological studies of people engaged in religious activities such as rituals, meditation, prayer, and speaking in tongues (glossolalia), which work on the autonomic nervous system to induce the altered states of consciousness that constitute ecstatic religious experiences.  This can work on the sympathetic nervous system (the arousal system) to induce states of hyperarousal and ultimately a feeling of ecstasy.  Or this can work on the parasympathetic system (the quiescent system) to induce states of hyperquiescence and ultimately a sense of bliss.

                                         A Ten-Minute Video on the Autonomic Nervous System

For example, Newberg and his colleagues have led neuroimaging studies of a group of Franciscan nuns engaging in the spiritual practice of centering prayer (Newberg 2018: 214-19).  Centering prayer requires that one concentrate one's attention on a particular prayer or phrase from the Bible and meditate on its meaning with one's eyes closed for a prolonged period--from twenty minutes to several hours.  Over time, the spiritual state of the person deepens until they feel open to God's presence.

Although the technique of centering prayer was first developed by some Trappist monks in the 1970s, it draws from the tradition of contemplative prayer that stretches back to the early days of Christian monasticism.

Newberg and his colleagues have found that centering prayer begins with increased activity in the prefrontal cortex, particularly in the right hemisphere, and in the anterior cingulate gyrus, which are involved in focusing attention.  The prefrontal cortex must then activate the thalamus, which can block sensory information getting into the parietal lobe, so that fewer distracting outside stimuli arrive in the visual cortex and parietal lobe.  A primary function of the parietal lobe is to gather all the sensory information we receive and use it to give us a spatial representation of our body in the world.  So that blocking sensory information from entering the parietal lobe can blur the boundaries between self and world, and we can feel a sense of oneness with everything in the universe, which could explain the experience of the nuns feeling intimately connected to God in their centering prayer.  Centering prayer is also associated with important structures in the limbic system such as the amygdala that are involved in intense emotions.


This doesn't explain much about the specific content of Paul's ecstatic visions.  But as Shantz argues, a neurobiological reading of 2 Corinthians 12:1-4 can illuminate two of the puzzling features of Paul's ecstatic experience--his confusion about the location of his body and his inability to speak about what he heard in heaven (Shantz 2009: 93-109).  Paul said that when he ascended into Heaven, he did not know whether he was "in the body or apart from the body."  And he "heard inexpressible things, things that no one is permitted to tell."  Why was Paul so bewildered about his body?  And why was he so confused about how to describe his experience?

To answer the first question, as Shantz suggests, we can begin by considering how our normal experience of our body depends on the representation of our body in our brain.  Our brain carries a neural map of our body--sometimes called the homunculus map--composed of two maps:  a set of sensory correlates on our parietal lobes and a set of motor correlates on our frontal lobes.  Amazingly, these bodily coordinates are mapped out on our brains from our toes to our tongue.  This neural mapping of the body is connected with the somaesthetic association area in the parietal lobes, with the right parietal lobe being predominantly in control.

                                                                   The Homunculus Map

The normal functioning of this somatosensory representation of the body in the brain gives us our subjective sense of our embodiment and the orientation of our body in space.  But as I have noted in some previous posts, damage to the right cerebral hemisphere (such as from stroke) can produce a loss of body identity, such as in somatoparaphrenia, when people feel that their left leg or arm is not really theirs.  

Shantz suggests that Paul's ecstatic experience of trance put him into an altered state of consciousness that was "somewhere between" the "healthy and impaired functioning" of the brain's somatosensory experience of bodily identity (98).  Although she does not cite any specific neurobiological studies of ecstatic experiences to support this idea, she speculates that Paul's religious mind could have altered (through prayer or other religious activities?) the functioning of his brain so that, on the one hand, the bodily sensations from his body and from his somatosensory cortex were blocked from consciousness, but, on the other hand, the neural impulses from the orientation association area were intensified.

This then leads Shantz into her explanation of Paul's experience in ascending into Heaven:

". . . The human mind is left to interpret this strange combination of neurological silence and noise in an intelligible way.  Thus, the body is perceived as present, but its sensations--its weight, boundaries, pain, or voluntary motion--are all absent from consciousness.  In an attempt to interpret these phenomena as coherently as possible, ecstatics frequently report the sensation of floating or flying without physical boundaries between themselves and the people and objects in their awareness.  Not surprisingly, descriptions of ascent are also common in interpretations of ecstatic experiences.  Paul's ascent is among them.  Like other ecstatic thinkers, Paul genuinely could not know the status of his body by using the sensate signals that would normally inform him.  The question of whether he was in the body or outside it is not simply a rhetorical means of dismissing the issue; it is rather an account of one of the phenomena of trance" (98).

This is a speculative explanation.  But if we assume that for every mental experience there must be some neural correlates in the brain, then, as an extrapolation from what we know about the normal and abnormal functioning of the brain's system for bodily awareness, this is a plausible neurobiological explanation of how Paul's ecstatic experience of ascending to Heaven arose from his brain.  

In principle, we could find experimental support for this by doing brain imaging studies of people having ecstatic experiences comparable to Paul's.  And yet, in this reliance on brain imaging research, we should always keep in mind, as I have argued in previous posts, that brain imaging is not mind reading.  For example, while fMRI detects blood flow in the brain, it's a matter of interpretation as to what that reveals about the structure and functioning of the brain.  Moreover, none of this research gives us direct access to the subjective consciousness of the people we are studying: ultimately, scientific observers must rely on the patients' verbal reports of what they are thinking and feeling.  Neurologists like Picard face the same problem: when they electrically stimulate some part of a patient's brain, they cannot know what is happening in the patient's mind until the patient reports what he thinks is happening in his mind.

But then what would be the neurobiological explanation for the ineffability of Paul's experience--his confusion about how or even whether he could describe his experience?  This is a general problem for the scientific study of religion because so much of religious experience is reported as indescribable in ordinary language, and this creates the suspicion that the object of such ineffable experience is not real.

As with her answer to the first question, Shantz's answer to this question is speculative, and yet plausible so far as it is grounded in present neurobiological knowledge of how some brain activity in the right hemisphere can be ineffable when it is cut off from the language centers in the left hemisphere (101-108).

The primary language centers of the brain are all in the left hemisphere--Broca's area, Wernicke's area, the angular gyrus, and the primary auditory cortex.  And yet the right hemisphere does seem to process the emotional nuances of language.

Brain imaging studies of people during altered states of consciousness (such as that induced by hallucinogenic drugs, meditation, and speaking in tongues) show brain activity dominated by the right hemisphere rather than the left hemisphere.  We can infer, therefore, that if mystical experiences like Paul's ascent to Heaven arise primarily from the right hemisphere of the brain, the language processing centers in the left hemisphere might struggle to express these experiences in clear language.  

But then since we have no direct access to the mind of Paul or any other mystic, or any other human being for that matter, we must rely on their verbal or written reports of their mystical experiences.  And so, to the extent that mystical experiences are truly ineffable, we cannot understand what they are--unless, of course, we have mystical experiences of our own.


So what does all of this tell us about the truth or falsity of religious claims, or whether God--or any supernatural being--really exists?

The scientists studying the neurobiology of religious experience often report that people who have had an ecstatic experience say that it was "infinitely more real" than any other experience in their life.  Does that intense feeling of the reality of the supernatural object of their experience prove the real existence of the supernatural?  Or could this subjective imagination of the reality of the supernatural be delusional?  After all, even religious believers often dismiss the religious experiences of people in different religious traditions as illusions.  For example, most religious believers who are not Mormons will doubt whether Joseph Smith really did meet the Angel Moroni, who delivered to him the golden plates on which was written the Book of Mormon.  And, of course, skeptics or atheists do not see religious experiences as testifying to the truth of religious claims about the supernatural.

But still it's hard to see how we could ever prove that there has never been a true revelation of the supernatural through religious experience.  And that's why the Reason/Revelation debate remains unresolvable.

I see the neurobiology of religious belief as evidence for there being a natural desire for religious experience rooted in the evolved nature of the brain.  Some of the evolutionary psychologists of religion (like Justin Barrett) will see this as showing that God guided natural human evolution so that the human brain would be naturally inclined to belief in God.  Others will see this natural evolution of religious belief as an evolved propensity of the human brain to delusional belief in God.  As far as I can see, evolutionary neurobiology is open to either interpretation.

As I have argued in some previous posts, what we see here is the natural emergence of the soul in the brain.  Some religious believers will say that the creation of the human soul was a supernatural miracle by God acting outside the natural order of evolution.  But some theistic evolutionists will say that God chose to use the natural evolution of the brain so that the soul could emerge in the brain.


Gschwind, Markus, and Fabienne Picard. 2016. "Ecstatic Epileptic Seizures: A Glimpse into the Multiple Roles of the Insula." Frontiers in Behavioral Neuroscience 10:21.

Newberg, Andrew. 2018. Neurotheology: How Science Can Enlighten Us About Spirituality. New York: Columbia University Press.

Picard, Fabienne. 2023. "Ecstatic or Mystical Experience through Epilepsy." Journal of Cognitive Neuroscience 35 (9): 1372-1381.

Schweitzer, Albert. 1931. The Mysticism of Paul the Apostle. New York: Henry Holt.

Shantz, Colleen. 2009.  Paul in Ecstasy: The Neurobiology of the Apostle's Life and Thought. New York: Cambridge University Press.

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