In 1998 a strange story emerged from a village in the remote Kham region of eastern Tibet. It is said that a rainbow appeared one day above the cabin of Khenpo A-chos, a devout lama who had continued to practice and teach Buddhism despite the severe restrictions of the Chinese government. He was in his eighties, but not sick. Nevertheless, he lay down on his bed, began reciting the Tibetan mantra “Om mani padme hum,” and died.
Shortly after the nuns, monks, and others who studied with him began the Tibetan Buddhist prayers that accompany death, they noticed that Khenpo A-chos’s skin began to turn soft and pinkish. His students hurried to another lama to ask about this, and he told them to cover the body and continue their prayers. They placed a thin yellow monk’s cloak over him, and as the days passed, they saw that his body was shrinking. By the end of the week, the students reported, nothing remained—just a few hairs left on the pillow. Khenpo A-chos had apparently become what is known in Tibetan Buddhism as a rainbow body.
This story spread through Buddhist circles, making its way to the United States, where Brother David Steindl-Rast, a Benedictine monk, heard it. He realized that the miraculous event had implications for Christianity: “If we can establish as an anthropological fact that what is described in the resurrection of Jesus has not only happened to others but is happening today,” he has said, “it would put our view of human potential in a completely different light.”
Brother David enlisted the aid of Father Francis Tiso, an associate director of the secretariat for Ecumenical and Interreligious Affairs at the United States Conference of Catholic Bishops in Washington, D.C., who also has a doctorate in Buddhist studies. Father Tiso journeyed to Kham with a translator and recorded the testimony of several people who had witnessed the events.
The lama who had been consulted by the students, Lama A-chos (no relation), told him that achieving the rainbow body “is a matter of inner realization. It’s not a philosophical idea. It’s not a metaphor.” He also showed Father Tiso photographs of himself taken while meditating, indicating what looked like light radiating from his body.
Did these things truly happen? Certainly they were real to Lama A-chos and perhaps even to Father Tiso. “It’s one of my regrets that I couldn’t take a photograph of his photos. It was too dark, and a flash would have washed out the photos,” Father Tiso says. “People criticize the research, saying, ‘Well you didn’t do this or that,’ and of course, it’s unscientific. But there is an interface between what we might call mystical phenomena and observable phenomena that one day may be documented.”
The interface Father Tiso is referring to is the contentious place where people are searching for proof of the existence of the human soul. What information counts as evidence depends on how you define “evidence.” On one side there are the mystical phenomena reported by serious practitioners in all spiritual traditions. These experiences cannot easily, if at all, be measured or tested by scientific methods. On the other side are observable phenomena—the backbone of empirical experimentation—that so far have given only the vaguest hints of a consciousness that persists outside of the physical body. History is filled with attempts to prove that the soul is real. In 1921 physician Duncan MacDougall devised the famous “21 grams” experiment to detect the exit of the soul from the body by measuring how a person’s weight changes immediately after death. He monitored six deaths and reported that the people lost anywhere between 11 and 43 grams at death (not always 21 grams as is popularly reported), which he took as the material weight of the soul. Follow-up experiments failed to replicate MacDougall’s findings, and some researchers attributed the weight loss to straightforward processes like the evaporation of water from the body.
Nevertheless, Gerard Nahum, a physician and director of medical affairs for the pharmaceutical company Berlex, has been working on a different kind of follow-up experiment for the past two decades. All you need, according to Nahum, is an extremely sensitive scale and an array of electromagnetic sensors. “In principle, it’s a pretty simple experiment,” he says. He proposes surrounding the body with a spherical array of electromagnetic detectors (microwave, infrared, X-ray, gamma ray) to pick up any type of escaping energy. “When a conscious entity dies,” Nahum says, “all of what’s embodied in it cannot just simply disappear. It needs to either be transformed into something else within our space-time, or it needs to transcend its existence here and move on to someplace else where it could potentially remain intact.”
Nahum has tried to sell his idea to engineering, physics, and philosophy departments at Yale, Stanford, and Duke universities; they all turned it down. Even the Catholic Church took a pass. “They didn’t see that there was a significant upside to performing this type of experiment because they already knew what the answer would be,” Nahum explains. Researchers in England, the Netherlands, and the United States are searching for the soul in a different way, focusing on experiential as well as material evidence. At places like the Institute of Noetic Sciences in Petaluma, California, researchers examine various aspects of consciousness to see if it functions independently of the physical brain, implying the existence of an independent life spirit.
At the University of Virginia Health System’s Division of Perceptual Studies, or DOPS, scientists are studying an array of anomalous phenomena, including near-death experiences, out-of-body experiences, and memories of past lives. Bruce Greyson, a psychiatrist at UVHS and director of DOPS, is a pioneer in the study of near-death experiences. First described in ancient times, near-death experiences, or NDEs, happen when patients are critical or when their hearts have briefly stopped. Typically, they describe seeing visions of a bright light and feeling themselves carried down a tunnel toward it. Along the way deceased relatives or spiritual figures may appear offering comfort. It is by almost all reports a transformative experience.
Greyson, a soft-spoken man who has studied NDEs for 30 years, explains that although he does not necessarily believe in the existence of the soul, that possibility inspires his curiosity. “I believe that our current understanding of humans is woefully inadequate,” he says. “I think the spiritual traditions that we have are good starting points for researchers to look at what might be going on. I don’t accept them as definitive answers. I accept them as starting points for developing hypotheses that we can test, but I’m not happy with the answers we have now, either from science or from religion.”
Greyson reports that about 10 percent of the people who go into cardiac arrest have an NDE and report knowing details of activities that occurred while they were unconscious. Frequently, individuals tell of watching from above the operating table as doctors and nurses work on their bodies. From a scientific standpoint, the most significant aspect of many NDEs is that the individual’s brain should not have been functioning at the time of the event. “We have a lot of well-documented cases where we have EEG and other evidence that the brain is not functioning, and yet people will say, ‘I was thinking clearer than I ever have before,’” Greyson says.
Dutch cardiologist and near-death researcher Pim van Lommel notes that, at the moment of an NDE, “these people are not only conscious, their consciousness is even more expansive than ever. They can think extremely clearly, have memories going back to their earliest childhood, and experience an intense connection with everything and everyone around them. And yet their brain shows no activity at all.”
If consciousness is the product of brain activity, near-death experiences should not happen. At the very least, the contrary evidence suggests that the standard understanding of consciousness is incomplete. Peter Fenwick, a senior lecturer at the Institute of Psychiatry at Kings College London, wrote in a paper, “The brain-identity theory says that consciousness ends with brain death. But if it can be shown that people can acquire information when they are unconscious and out of their body, it would be indisputable evidence that consciousness is separate from the brain.”
Again, the question comes back to the definition of evidence. Greyson attempted to document an NDE by programming a laptop computer with simple colored images (an airplane, a sailboat, a butterfly, a flower, a kite), one of which was displayed on the computer screen at random. He placed the laptop on top of a monitor about 10 feet off the floor of an operating room, beyond the view of patients undergoing heart surgery. In this operation, doctors induced cardiac arrest in the patient. If any of the patients had been able to escape their bodies and observe the room from above, they would have been able to see the computer screen and describe it later.
Greyson ran his experiment on 50 patients, but not one of them reported having an NDE. On the other hand, most denied that they had ever been unconscious at all. “One of the factors involved is that, before their cardiac arrest was induced, these patients were all given medication that inhibited them from forming memories of the procedure,” Greyson says. “We underestimated how complete the drug-induced memory inhibition would be.”
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.