Wherein I try to use science, or at least scientists, to determine the existence or non-existence of the human soul. Originally published in Discover magazine but I can’t seem to find a working link online. It’s kind of a long read, so I’m posting it on a Friday to give you time to read it over the weekend, because there will be a quiz on Monday. Fair warning. I should note that I used tiny bits and bobs of the theories and personalities contained herein when constructing the character of Marcus Forget in my second novel The Failure.

“I heard people talk about immortality, but I ain’t seen it.”
— Private Witt, from Terrence Malick’s The Thin Red Line

The problem with proving the existence of life after death, and hence of the soul, in whatever form and however defined, is that most of us have been conditioned —sensibly so — to accept only the evidence of our senses. By that standard, there really is no way to verify the afterlife, or an afterlife. By the evidence of the senses, when brain activity stops, you stop. The rest is faith, or belief, or fantasy, depending on your point of view.

In recent years, however, science has asked us to trust the evidence of things unseeable even with the most powerful microscopes, things that can’t be measured with our most sensitive devices, things that exist only in theory, or because theory requires their existence, and so they must exist. In quantum mechanics, science supposes that tiny forms of matter or energy, qbits (quantum bits), can exist at the same time in two different places in once (called “superposition”), or at different times in the same place. String theorists, looking for a way to explain the physical universe, have hypothesized a number of dimensions outside the three (or four, if you include time) available to our perception. The number ranges from five to eleven, depending who’s counting. Black holes in space are identified by the absence of the visible.

We’re asked to believe in these unseeable things rather than the unseeable things of the mind or soul or spirit because, whether these things finally prove true or untrue, there’s sound scientific reasoning behind quantum mechanics and string theory and black holes, whereas belief in life after death requires a leap of faith that extends — most people think — beyond the reach of science.

Which hasn’t prevented science, or at least some scientists, from trying. The mystery of consciousness — as outlined in Western thought by Cartesian dualism, the mind/body split defined by René Descartes, which seated consciousness firmly in the brain, where it has remained comfortably for a few centuries since — has become a hot topic as advances in the fields of neuroscience and quantum mechanics have enabled new theories of the origins and nature of the mind that go well beyond what Descartes dreamt of in his philosophy.

Even areas which have in the past been overlooked by conventional science — reincarnation, out-of-body or near-death experiences (OBEs and NDEs, respectively) — have benefited from serious, systematic scientific investigation. While there may as yet be no concrete way to “prove” that past lives carry over into present lives, or that the soul or consciousness in some form exists separately from the physical functions of the body, piles of data and a tangle of newly-developing theories suggest that the idea of an afterlife, in some form, however nebulous (or not) certainly bears further scrutiny.

Earlier, funnier attempts to prove the existence of the soul included the 21 Grams experiment. You may have seen the movie 21 Grams, whose title stood for the amount of weight the human body supposedly loses at the exact time of its death. The theory being, of course, that the soul weighs exactly 21 grams, and the weight loss is attributable to the soul leaving the body. This figure was arrived at by Duncan McDougall in 1901, who, according to Mary Roach in her thorough and highly entertaining book Spook: Science Tackles The Afterlife, describes how McDougall contrived to lever a dying patient at the Consumptives Home in Dorchester, Massachusetts onto an extraordinarily sensitive commercial scale used for weighing silk. McDougall registered a weight loss of 21 grams at the time of the unnamed patient’s expiration.

Problem: there’s many reasons why the patient may have suddenly lost weight at time of death, the most persuasive of which Roach calls “insensible loss” — body weight that’s constantly being lost through evaporating perspiration and water vapor. MacDougall and his successors never managed to replicate exactly the results of their initial experiment — some patients even gained weight at the time of death — and the current scientific consensus is that no consistent results have been or are likely to be derived from loss of body mass at the moment of death.

The spiritualist vogue in the late nineteenth and early twentieth century did little to advance the serious case for the soul’s existence, with so-called mediums and their table rapping and yards of “ectoplasm” (usually some kind of lace pulled, as Roach reports, surreptitiously from their vaginal cavities).

But there’s always been a parallel strain of more persuasive evidence — evidence for measurable extra-sensory perception, anecdotal reports of similar near-death experiences (NDEs) and out of body excursions (OBEs). It’s this more persuasive strain that has received the benefit of at least some serious scientific inquiry. Dr. Charles Tart, a professor of psychology at the University Of California at Davis, has done a great deal of empirical work in the area of parapsychology, encompassing not just OBEs and NDEs but elements of what Tart calls “indirect evidence that mind is something more than the body.” He breaks this indirect evidence down into five categories: “the big five, as I like to call it: telepathy, clairvoyance, precognition, psychokinesis, and psychic healing. These are your basic forms of extra-sensory perception, which each have hundreds if not thousands of experiments showing that you get effects that way.”

Direct evidence, in Tart’s view, is “stuff that tries to get more directly at the question of whether we might survive death.” Into this category fall NDEs and OBEs. For these there is “nowhere near as much experimentation, and a more difficult methodology. The data at this point produces a ‘maybe’ answer. Strong enough that you really should look at it, but I wouldn’t want to say ‘prove it,’ by any means.”

Tart defines an OBE as an event where “you experience yourself as being located somewhere else than where your physical body is, and – the and part is particularly important – you have a relatively clear state of consciousness. So you can reason about how this experience is impossible, for instance. You couldn’t possibly be wide awake like this and somewhere else, but, dammit, there you are. The typical reaction of someone who’s had an OBE is ‘I no longer believe that my soul is going to survive death. I know it. I’ve had direct experience of my mind outside of my body.’

“Now we as outsiders can quarrel with them. We weren’t there, we didn’t have the experience. But to people who’ve had the experience, they feel that they know. Same sort of thing with people who’ve had NDEs. Typical reaction is ‘I no longer believe in survival, I know it’s true.’ OBEs and NDEs can overlap, but the distinction is usually this: I’ve defined an OBE as where your consciousness feels pretty much normal. An NDE might start with an OBE, but it almost always goes into an altered state of consciousness. That’s when people talk about it being so difficult to describe in ordinary language, new types of knowing, things like that. It’s the altered state aspect that distinguishes the two.”

Tart’s own experiments with regard to OBEs and NDEs is long-standing, and at least within the small field of parapsychology, well-known. He conducted a famous experiment in the 1960s where a subject was able to read back correctly to Dr. Tart a five digit number he had placed out of sight of her body in a sleep laboratory.

“The funny thing is,” says Tart, “when I talk about that, and say that she correctly gave me the five-digit number, somebody will inevitably ask ‘Did you know the number?’ And when I admit that I did, they’ll say ‘Oh, it was just telepathy.’ I’m sorry, the first experiment like that in the world, and I didn’t think to control for mere telepathy. Silly me!”

Although Tart was the first, he’s not the only person to attempt a scientific exploration into OBEs. Bruce Greyson at the University of Virginia, is currently working with defibrillator insertion patients just after they come out of anesthesia. According to Mary Roach, who describes the experiment in Spook, Greyson has positioned a laptop with a randomly assigned, constantly-changing screen-saver, high up in the room, where the patient — whose heart will technically stop for up to four minutes as part of an operation designed to correct his arrhythmia — will not possibly under ordinary circumstances be able to see the image on the laptop. If, post-op, anyone does, it would be pretty persuasive evidence that OBEs do happen. To date, by all reports, no such luck.

“A constantly changing target on a laptop is a more sophisticated approach,” comments Tart. “Trouble is, though, you tend to find that’s not where people have their NDEs and OBEs. They have them in a different room. Additionally, in surgery nowadays they give you a drug [Versed, a mild tranquilizer] that screws up your memory. It’s amazing that any get reported at all with that drug in them. Having said that, I suspect he’ll get one sooner or later. It’s actually been tried very few times so far.”

Why not? “There’s something you have to understand here,” Tart explains. “Because this is such an interesting topic, people assume there’s a big establishment working on all aspects of parapsychology and NDEs and so on. There’s hardly anybody working on it. I may talk about hundreds of experiments for some of the more established phenomena, but that’s been accumulated for over half a century.

“Reverting to my role as a psychologist — you’d think whether we have some aspect that survives death would be a pretty burning question for most people, and we ought to research it. Yet it’s almost impossible to get research money for this sort of work. It’s crazy.”

Clearly there’s a strong sense among many “conventional” scientists that, while the study of parapsychology may not be crazy, exactly, most or all paranormal mind-events can be explained in neurological (i.e., brain-and-body rooted) terms. Harvard professor of psychology Steven Pinker has noted a recent Swiss study whereby NDEs could be artificially induced, even turned on and off, “by stimulating the part of the brain in which vision and bodily sensations converge.”

Tart responds, “The article Pinker’s referring to is almost certainly Stimulating illusory own-body perceptions: The part of the brain that can induce out-of-body experiences has been located. Nature, 2002, volume 419, pp. 269-270 by Olaf Blanke and colleagues. I’ve known about that one for years, and it’s another example of rather grandiose claims (the subtitle, particularly) based on almost total ignorance of what OBEs are actually like. One patient had really distorted perceptions of her own body with brain stimulation and vaguely reported feelings of ‘lightness’ and ‘floating.’ The Blanke report may have some relevance to some aspect of OBEs, but hardly explains them.’

“There’s a similar attempt to ‘explain’ NDEs on the basis that test pilots in high-speed centrifuges experience a closing in of vision, sort of like a tunnel, just before the G forces cause them to black out, but the overall experience of the pilots has very little in common with NDEs. My experience, unfortunately, is that theories which ‘explain away’ things like OBEs and NDEs are welcomed in mainstream journals even when they are of low quality, as that’s what the establishment wants to hear, while articles of much higher methodological quality that show the existence of things we don’t understand get rejected out of prejudice.”

One way to explain the phenomenon of NDEs and OBEs — one of the more interesting, scientifically — is through quantum mechanics. Stuart Hameroff, an anesthesiologist who’s spent many years studying brain functions, and who in collaboration with the Oxford mathematician and physicist Roger Penrose has developed a model for consciousness that relies on quantum processes at the very smallest scale of the brain’s functions, explains that “the BBC did a show four or five years ago called The Day I Died. There were two big NDE studies in Europe, and they asked the scientists involved how they could explain NDEs and OBEs, and they said, ‘We don’t know, ask Penrose and Hameroff.’ I said that I think consciousness under normal circumstances occurs at the level of space/time geometry in the brain. In the microtubules in the dendritic webs in the brain. Between the ears. But the fluctuations extend down to the Planck scale. That’s because the microtubules are driven bioenergetically to be in this coherent state. When the blood supply, and the oxygen stops, things kind of go bad, and the coherence stops, but the quantum information at the Planck scale isn’t lost. It may just dissipate into the universe at large, but remain somehow entangled in some kind of functional unit, kind of like a hologram maybe. It’s possible that could exist for a brief period of time or maybe indefinitely. If the patient is revived, the quantum information gets picked back up again.”

The Planck scale Hameroff references is, in essence, the unimaginably small energy scale where the effects of quantum gravity (about which there exists much debate and many competing theories) become strong. The nature of reality at the Planck scale, according to some physicists, may be the fundamental stuff of the universe. Which happens to be exactly what Hameroff and Penrose believe — but for them it goes further, into the mystery of consciousness itself.

“Penrose came up with a specific threshold that is conscious,” Hameroff explains, “through [Kurt] Gödel’s [incompleteness] theorems [in summary: any given theory or system of ideas will contain true but unprovable statements] and so forth, that made the connection between the quantum possibilities in the universe itself and the quantum processes in the brain. He suggested quantum superpositions in the brain that would reach this threshold and have conscious moments, but he didn’t know what the structures were. I had been working in an area one step down from where Penrose was looking, in the neurons. I was working on microtubules inside the neurons, which are constructed as beautiful molecular biological computers, processing information within cells — kind of the onboard computer or CPU for living cells. I needed a mechanism and he needed a structure, so we teamed up.”

The Hameroff-Penrose model for consciousness is called ORCH OR, which stands for “orchestrated objective reduction of quantum coherence in brain microtubules,” which in essence means that Penrose and Hameroff believe that “consciousness is a process on the edge between the quantum and classical worlds. Biology is leveraged precisely so that quantum level effects can be amplified to, say, move an arm or say a word. Because of the scale and sensitivity of biology,” Hameroff explains, “it can interface with quantum processes.”

But it doesn’t stop there. Penrose has theorized that there exists at the Planck scale a realm (“Don’t call it a dimension,” Hameroff jokes) of Platonic ideals that influence, however subtly, the workings of our mind.

“It’s the tiniest scale imaginable,” says Hameroff. “The universe is after all mostly empty space. If you go down in scale, twenty-five 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. String theory tries to describe this but string theory still requires a background space/time. The point is that there’s some kind of structure and volume pixels, if you will, at Planck volumes, that are the stuff of the universe. What they’re made of, you can’t even say. You get these patterns at the Planck scale that are constantly evolving and changing. We know that it’s arranged non-locally, so patterns repeat over spatial domains, if you will. This is where Penrose says the non-computable [Platonic] influences are embedded as non-local patterns. So even though they’re very, very tiny, they repeat everywhere. So wherever you go, there they are.”

Which suggests the obvious question: where did these non-computable Platonic influences come from? “I asked Roger the same thing,” he replies, “and he said, ‘The Big Bang, where else?’”

In other words, consciousness — all consciousness, of which you and I partake and yet which somehow permeates every aspect of the universe — was created in the same moment as the universe itself was created. In fact this is exactly what Italian mathematical physicist Paola Zizzi has termed “The Big Wow,” shorthand for her description of the connection between “the very early quantum computing universe and our mind.”

So Cartesian dualism, the mind/body split, has a correlate in the quantum/classical split? “I think that’s true,” says Hameroff. “I think consciousness is actually the transition from the unconscious quantum, choosing classical states.”

ORCH OR remains highly speculative, like many theories, and held in low regard by cognitive scientists like the afore-mentioned Steven Pinker, who, writing in Time Magazine on The Mystery Of Consciousness, represents the view of much conventional science when dismissing Penrose’s quantum approach by saying “to my ear, this amounts to the feeling that quantum mechanics sure is weird, and consciousness sure is weird, so maybe quantum mechanics can explain consciousness.” Pinker prefers to locate consciousness, however derived, exclusively in the physical activity of the brain. Meaning that when the brain dies, consciousness dies. That is to say, you die.

“As far as I know,” elaborates Pinker by email, “the quantum/microtubule theory hasn’t given rise to models that accomplish any task that is part of intelligence. It can’t be a coincidence that a big part of intelligence correlates perfectly with consciousness — that when I search for my keys, or add up a column of numbers, or decide whether my socks match, the states I feel myself going through correspond to some of the high-level states of an algorithm for accomplishing those feats. Any theory that tries to account for consciousness but says nothing about intelligence is incomplete, and until the quantum-microtubule theory can show how the brain solves problems (even simple ones) I doubt that theoretical neuroscientists will adopt it.”

“I completely agree that microtubules must be capable of computation, information processing, or intelligence, as Pinker says, to play a role in consciousness,” responds Hameroff. “In the late 1980s I collaborated with Steen Rasmussen at Los Alamos National Labs on cellular automata models in microtubules (microtubule cytoskeletal automata). We did computer simulations and showed that the particular geometry of microtubules is extremely good for self organizing computation. In a more recent study [Steen Rasmussen, Hasnain Karampurwala, Rajesh Vaidyanath, Klaus Jensen, Stuart Hameroff. Computational connectionism within neurons: A model of cytoskeletal automata subserving neural networks Physica D 42:428-449 (1990)] we simulated two microtubules connected in parallel by linking proteins (known to occur) forming an information processing network. We ran a standard learning task using an error correcting parameter called the Hamming distance and showed that two microtubules linked together randomly could learn to recognize patterns. It appears we have done what Pinker requested 17 years ago.”

For his part, Hameroff’s colleague Roger Penrose notes in his book Shadows Of The Mind: A Search for the Missing Science of Consciousness that “human physicists are, as yet, largely ignorant of [the quantum approach to consciousness] is, of course, no argument against Nature having made use of it in biology. She took advantages of the principles of Newtonian dynamics long before Newton.”

On a more general level, Tart comments, “In terms of the ordinary person, whether or not we have a soul — what kind of scientific basis do we have to assume that mind must be something more than just the body? I can boil that argument down very easily: if you assume that mind is nothing but electro-chemical processes within the brain, body, and nervous system, then you can with great confidence say what that can and cannot do. For instance, we can say that, yeah, there’s a little electro-magnetic radiation from my brain. But it is so weak that it falls below the noise level. I couldn’t possibly affect you by you picking up radiation from my brain with me sitting here in Berkely, California. Yet if you do experiments where you set it up so given our current materialistic view of physics nothing could possibly happen, and something does happen, you have concrete evidence that mind can do something that brain and body can’t. You have to look at other possibilities for mind.”

One such possibility, long accepted in some Eastern cultures but much less so in Western culture, is reincarnation. After all, as Hameroff notes about the disembodied quantum information released when a patient’s brain activity stops, “if the patient isn’t revived, it enters the universe at large, and maybe it gets picked back up again by someone someday, who knows?” The idea of reincarnation has received seriously systematic attention from a unit of the University Of Virginia’s Division Of Perceptual studies, funded initially by a grant from Chester Carlson, the inventor of xerography (i.e. Xerox). The research was begun by Dr. Ian Stevenson as far back as 1961, and has carried on after both Stevenson’s and Carlson’s death.

Jim B. Tucker, M.D., author of Life Before Life: A Scientific Investigation of Children’s Memories of Previous Lives, has helped carry on Stevenson’s work at UVA, which primarily consists of constructing a searchable database of recorded cases of what Tucker prefers to call “carryover” rather than reincarnation, both to sidestep the cultural baggage of the term and because, frankly, his study is concerned with identifying the phenomenon and not speculating as to its underlying cause.

“It’s been a project that’s been years in the making,” explains Tucker. “With each case, we’ve got interview notes, a registration form, and other information, all of which is put on a coding form that has two hundred variables — pretty much everything you can think of, from the occupation of the parents, a lot of the characteristics of the child, and so on. Unfortunately, due to that coding process, it’s very labor intensive. We’ve got 2500 cases registered in our files, and so far we’ve got 1400 of them coded into the computer database.”

The results are occasionally startling — particularly so in cases where birthmarks on a child who recalls memories from a specific past life match wounds received by the person whose life experience has purportedly “carried over” into the child’s memory.

“Those cases are out there. Ian Stevenson published this huge work documenting 225 of them. Obviously with birthmarks, if you get a little blemish, you don’t make much of it. But some of these are pretty dramatic.”

The birthmarks are difficult to dismiss, because they don’t rely on the vagaries of interviewing a child, whose capacity for fantasy or imagination may sometimes dilute the verifiability of his or her memory. But even given that, Tucker notes “We know so little about what might cause these things that to attribute them to reincarnation would be purely speculative.”

At some point, though, the mass of scientific evidence pointing to the existence of something apart from a purely physical origin/function/demise of consciousness becomes persuasive, at least to the open-minded. The question remains, and will remain for many years to come, most likely: persuasive of what, exactly? The existence of the soul? The afterlife?

It’s entirely possible that sometime in the future science will advance to such a degree that we are able to say, definitively, that life after death exists, or doesn’t exist. We may be able to measure the dimensions of Heaven and Hell, and open a channel directly to God, who may or may not turn out to be a small koala bear-like mammal living in a distant star system. For now, a substantial number of people still believe in leprechauns. The nature of the soul, the existence of God, of an after-life: these questions have obsessed us since the dawn of human consciousness, and will likely continue until its sun has set. Faith remains aloof from science, though some would argue that faith in science is a substitute for religion and thus the replacement of one false idol with another. Belief and doubt are hard-wired into our system. The more we learn, it would seem, the less we know.

Except, perhaps, when we sleep:

“I think dreams are quantum information, basically,” says Hameroff. “And in fact the logic of dreams matches quantum logic.”

Sweet dreams.