The human brain is amazing. Though it is entirely physical, the brain can produce sensations that seem spiritual, soulful, supernatural.
Oliver Sacks, M.D., a professor of neurology, describes how the brain does this in a fascinating Atlantic article, "Seeing God in the Third Millenium: How the brain creates out-of-body experiences and religious epiphanies."
Here's some excerpts that I found particularly interesting. Below Sacks explains why people are so convinced that what they hallucinate is objectively real, not a product of their own brain -- which it is.
But the fundamental reason that hallucinations -- whatever their cause or modality -- seem so real is that they deploy the very same systems in the brain that actual perceptions do. When one hallucinates voices, the auditory pathways are activated; when one hallucinates a face, the fusiform face area, normally used to perceive and identify faces in the environment, is stimulated.
In OBEs [out of body experiences], subjects feel that they have left their bodies -- they seem to be floating in midair, or in a corner of the room, looking down on their vacated bodies from a distance. The experience may be felt as blissful, terrifying, or neutral. But its extraordinary nature -- the apparent separation of "spirit" from body, imprints it indelibly on the mind and may be taken by some people as evidence of an immaterial soul -- proof that consciousness, personality, and identity can exist independently of the body and even survive bodily death.
Neurologically, OBEs are a form of bodily illusion arising from a temporary dissociation of visual and proprioceptive representations -- normally these are coordinated, so that one views the world, including one's body, from the perspective of one's own eyes, one's head. OBEs, as Henrik Ehrsson and his fellow researchers in Stockholm have elegantly shown, can be produced experimentally, by using simple equipment -- video goggles, mannequins, rubber arms, etc. -- to confuse one's visual input and one's proprioceptive input and create an uncanny sense of disembodiedness.
And here Sacks debunks the supposed experience of heaven while comatose that Eben Alexander has parlayed into a best-selling book, slick web site, and such. In a previous blog post I also talked about why Alexander's tale shouldn't be taken seriously. Sacks says:
Alexander makes much of his experience as a neurosurgeon and an expert on the workings of the brain. He provides an appendix to his book detailing "Neuroscientific Hypotheses I considered to explain my experience" -- but all of these he dismisses as inapplicable in his own case because, he insists, his cerebral cortex was completely shut down during the coma, precluding the possibility of any conscious experience.
Yet his NDE was rich in visual and auditory detail, as many such hallucinations are. He is puzzled by this, since such sensory details are normally produced by the cortex. Nonetheless, his consciousness had journeyed into the blissful, ineffable realm of the afterlife--a journey which he felt lasted for most of the time he lay in coma. Thus, he proposes, his essential self, his "soul," did not need a cerebral cortex, or indeed any material basis whatever.
It is not so easy, however, to dismiss neurological processes. Dr. Alexander presents himself as emerging from his coma suddenly: "My eyes opened ... my brain ... had just kicked back to life." But one almost always emerges gradually from coma; there are intermediate stages of consciousness. It is in these transitional stages, where consciousness of a sort has returned, but not yet fully lucid consciousness, that NDEs tend to occur.
Alexander insists that his journey, which subjectively lasted for days, could not have occurred except while he was deep in coma. But we know from the experience of Tony Cicoria and many others, that a hallucinatory journey to the bright light and beyond, a full-blown NDE, can occur in 20 or 30 seconds, even though it seems to last much longer.
Subjectively, during such a crisis, the very concept of time may seem variable or meaningless. The one most plausible hypothesis in Dr. Alexander's case, then, is that his NDE occurred not during his coma, but as he was surfacing from the coma and his cortex was returning to full function. It is curious that he does not allow this obvious and natural explanation, but instead insists on a supernatural one.
To deny the possibility of any natural explanation for an NDE, as Dr. Alexander does, is more than unscientific -- it is antiscientific. It precludes the scientific investigation of such states.
Deeply wanting to experience the presence of God, a person's brain can produce the experience that is wanted. Nothing supernatural involved. So says Sacks:
Some religious people come to experience their proof of heaven by another route -- the route of prayer, as the anthropologist T. M. Luhrmann has explored in her bookWhen God Talks Back. The very essence of divinity, of God, is immaterial. God cannot be seen, felt, or heard in the ordinary way. Luhrmann wondered how, in the face of this lack of evidence, God becomes a real, intimate presence in the lives of so many evangelicals and other people of faith.
She joined an evangelical community as a participant-observer, immersing herself in particular in their disciplines of prayer and visualization -- imagining in ever-richer, more concrete detail the figures and events depicted in the Bible. Congregants, she writes:
Practice seeing, hearing, smelling, and touching in the mind's eye. They give these imagined experiences the sensory vividness associated with the memories of real events. What they are able to imagine becomes more real to them.
Sooner or later, with this intensive practice, for some of the congregants, the mind may leap from imagination to hallucination, and the congregant hears God, sees God, feels God walking beside them. These yearned-for voices and visions have the reality of perception, and this is because they activate the perceptual systems of the brain, as all hallucinations do. These visions, voices, and feelings of "presence" are accompanied by intense emotion -- emotions of joy, peace, awe, revelation.
Some evangelicals may have many such experiences; others only a single one -- but even a single experience of God, imbued with the overwhelming force of actual perception, can be enough to sustain a lifetime of faith. (For those who are not religiously inclined, such experiences may occur with meditation or intense concentration on an artistic or intellectual or emotional plane, whether this is falling in love or listening to Bach, observing the intricacies of a fern, or cracking a scientific problem.)
Sacks concludes with, not surprisingly, a cogent conclusion:
...Hallucinations, whether revelatory or banal, are not of supernatural origin; they are part of the normal range of human consciousness and experience. This is not to say that they cannot play a part in the spiritual life, or have great meaning for an individual. Yet while it is understandable that one might attribute value, ground beliefs, or construct narratives from them, hallucinations cannot provide evidence for the existence of any metaphysical beings or places. They provide evidence only of the brain's power to create them.