At the center of many near-death experiences is the sensation of the mind having left the body. Philosopher Thomas Metzinger of the Johannes Gutenberg University of Mainz in Germany hypothesizes that out-of-body experiences, or OBEs, may have actually spawned the idea of the soul. Early humans, he says, probably had such experiences and may have interpreted them as evidence that their minds separated from their bodies. This idea then could have evolved into the concept of a soul. Metzinger calls this his “soul hypothesis” and suggests that once the human brain had experienced out-of-body events, “it was a highly rational belief to assume the possibility of disembodied existence.”
Although Hameroff does not talk overtly about the soul, he invokes a similar idea.
The question is, what causes out-of-body experiences? Olaf Blanke, a neuroscientist at the Swiss Federal Institute of Technology in Lausanne, actually induced an OBE in a patient by stimulating the temporal-parietal junction (a part of the brain important in body orientation). “Each time we stimulated that area, the patient, who had never had an out-of-body experience before, experienced one,” he says. “While we were stimulating it, she was awake and not impaired in any sense, and she told us that she saw the world, including us three investigators and herself lying on the bed, from this elevated perspective.”
If, as Blanke suggests, out-of-body experiences may be a product of a temporary brain stimulus, why do they leave such a deep and lasting impression? The effects of a near-death experience (often involving an OBE) literally change people’s behavior. “As a psychiatrist,” Greyson says, “what was most impressive to me was how people changed as a result of a near-death experience. It’s just one experience that takes place in maybe a fraction of a second, and it changes their lives. Psychiatrists spend years and years trying to help people make fairly small changes in their lives, and here comes this experience which in a blink of an eye totally transforms reality. If we can figure out what’s going on there and tap into that power, it would be an important tool for us to use. Basically, they come back believing that the golden rule is the way the universe works, just like gravity. What you do to other people gets done to you, so they come back with a different attitude toward almost everything. Some people change their careers, their relationships, how they do things. Some become more spiritual or more altruistic.”
Greyson has followed individuals for 20 years after they experienced an NDE. “For the most part,” he says, “the changes they made after having an NDE have persisted.”
Perhaps the most surprising scientific evidence for the soul comes from quantum mechanics—specifically, from investigations of the subatomic phenomena that produce consciousness. Stuart Hameroff, an anesthesiologist who has spent many years studying brain functions, has collaborated with renowned Oxford University polymath Roger Penrose on a model that explains consciousness as the result of quantum processes occurring in tiny structures called microtubules in brain cells. “I think consciousness under normal circumstances occurs at the level of space-time geometry in the brain, in the microtubules,” Hameroff says. “But the fluctuations extend down to the Planck scale [far smaller than an atom] because the microtubules are driven bioenergetically to be in a coherent state. When the blood supply and the oxygen stops, things go bad and the coherence stops, but quantum information at the Planck scale isn’t lost. It may dissipate into the universe but remain somehow entangled in some kind of functional unit, maybe indefinitely. If the patient is revived, the information gets picked back up again.”
Although Hameroff does not talk overtly about the soul, he invokes a similar idea—consciousness that exists separate from the body. The Planck scale is the unimaginably small distance at which current theories of gravity and quantum physics break down. Events at the Planck scale, according to some theorists, may fundamentally establish the nature of reality. For Hameroff and Penrose, the idea goes even further, into the mystery of consciousness itself.
“Penrose came up with a specific threshold that is conscious. He made the connection between the quantum possibilities in the universe and the quantum processes in the brain,” Hameroff says.
Penrose speculated that there must be structures in the brain that process these fragments of quantum consciousness, but he didn’t know what they were. Meanwhile, Hameroff had found computer-like components in the brain but couldn’t figure out how they worked. “I needed a mechanism, and he needed a structure, so we teamed up,” Hameroff says.
Penrose theorizes that there exists at the Planck scale a realm of Platonic ideals that influence the workings of our mind. “It’s the tiniest scale imaginable,” Hameroff says. “The universe is, after all, mostly empty space. If you go down in scale 25 orders of magnitude below the size of an atom, on the way down it would appear smooth and featureless. Then you begin to see structure or coarseness or irregularity, which is the Planck scale, the basement level of the universe. You get patterns at the Planck scale that are constantly evolving and changing. This is where Penrose says the noncomputable influences are embedded. Even though they’re very, very tiny, they repeat everywhere.”
Even if that idea answers where consciousness comes from, it raises the question: Where did the Planck-scale processes that cause it come from Penrose’s answer: They came from the Big Bang. In this view, consciousness—all consciousness—was created at the same moment when the universe was created. If the soul exists, it, too, might be anchored to our moment of cosmic origin. This is what Italian astrophysicist Paola Zizzi terms the “Big Wow,” shorthand for her description of the connection between “the very early quantum computing universe and our mind.”
Penrose’s ideas hint at a physical mechanism for consciousness that persists after death. “If a patient isn’t revived,” Hameroff says, “it enters the universe at large, and maybe it gets picked back up again by someone someday, who knows?” At the Division of Perceptual Studies, there are file cabinets bulging with case studies of people who think they know. Most of them are children who remember past lives: who they were, where they lived, what they looked like, what work they did, all sorts of details of a life.
Psychiatrist and physician Ian Stevenson, who founded DOPS, began gathering stories of past lives in 1960. He also made personal trips to verify and document the details, including reports of children with birthmarks corresponding to wounds the “previous personality” received and phobias related to the cause of death. Stevenson died early this year, but child psychiatrist Jim B. Tucker, author of Life Before Life: A Scientific Investigation of Children’s Memories of Previous Lives, is continuing his work. Tucker has helped build a database of 1,400 cases of possible reincarnation. At his office at DOPS, Tucker explains that with the stronger cases “kids tend to start talking about these memories at an earlier age. They talk about them with more emotion. They give a lot of details, including specific names about the previous life.”
Investigating reincarnation is an even thornier research problem than studying NDEs. Although almost every culture has stories of people whose souls returned after death, the evidence for that return consists mostly of recollections and anecdotes. Tucker does his best to examine as many of the memories in each case as possible. Sometimes he locates family members and consults local historians to confirm information. Nevertheless, Tucker says, “We would never say that we have proved that reincarnation occurs. I think we can only say that we’ve produced evidence for it.”
The question comes back: What kind of evidence counts? For science, case studies like Tucker’s are never going to be enough to prove that a human soul survives death and is reborn. Like the rainbow body, they will remain as nothing more than folklore for those who require empirical proof. As the Buddhist holy man Lama A-chos told Father Tiso, “This is not a matter for the eyes; it is a matter for the heart.” The ongoing search for the soul may require both.