Question: What weighs the same as any of the following objects: a stack of five nickels, a chocolate bar, or a hummingbird? The answer is the human soul, which according to a bizarre, fringe science experiment in 1907 possesses a mass of 21 grams. That figure hasn’t quite achieved meme status in pop culture, but it is referenced in manga, hip hop, a podcast, books (including Dan Brown’s The Lost Symbol), television, and movies. One film in particular, the edgy, brooding crime pic 21 Grams, directed by Alejandro (Birdman, The Revenant) Iñárritu, provides a unique opportunity for reflecting on both spiritual and scientific questions.

Critically acclaimed on its release in 2003, 21 Grams garnered an 80% rating on Rotten Tomatoes. It presents three plot threads that eventually intersect. These stories are told in non-linear fashion, so that, as Iñárritu remarks, viewers are implicated in the characters’ lives as we help to “assemble” the pieces of this absorbing film.

Among the movie’s numerous virtues are Rodrigo Prieto’s lyrical cinematography and Sean Penn’s wistful and compelling characterization of Paul Rivers, a mathematician with a failing heart. Naomi Watts turns in an intense, believable depiction of Christina Peck, a woman who loses both her daughters and her husband in a car accident. Perhaps most memorable is Benicio Del Toro’s role as Jack Jordan, a serial bungler and recent convert to Christianity (his surname could suggest baptism), who drives a pick-up truck inscribed with “Faith” and “Jesus Saves.” Like some new converts, Jordan fixates on judgment-related verses, such as “Those whom I love, I rebuke and discipline” (Revelation 3:19), and his distorted application of “turn the other cheek” is cringe-worthy.

Benicio Del Toro in 21 Grams.Source

While many films offer subtle, parabolic opportunities for reflection on spiritual issues, 21 Grams is unique in its explicit foregrounding of the soul’s existence. The soul’s weight was putatively discovered by American physician Duncan MacDougall. To test his hypothesis, he obtained permission from six terminal patients in nursing homes, weighing them both before and shortly after they expired. One of the six appeared to have lost 21.3 grams at the time of death. (MacDougall also weighed 15 dogs; none lightened at death, thereby suggesting to him that dogs lack souls.) MacDougall’s research was disputed almost immediately, and has been ever since, for obvious reasons, including his overly small sample size, and the fact that just one of the six subjects was altered. The fact that MacDougall probably had to poison the dogs—he admitted that it was impossible to find 15 who were on the verge of expiration—hasn’t helped his reputation, either.

When we consider the relative popularity of the 21 grams figure in pop culture, it’s clear that, once again, an intriguing claim has been seized on uncritically, even though the science and ethics behind it are seriously flawed, rightly rejected by any sane, logical person. In fact, MacDougall should be relegated to the dustbin of history. Case closed.

Or is it?

As it turns out, such a dismissal may be premature, since there is a theory offered by a prominent Oxford physicist that suggests that, indeed, the soul may be, as we say, a thing, something physical if immaterial (more on that seeming oxymoron shortly). Dubbed the “quantum soul” by some, the theory’s official name is less sexy: Orchestrated Objective Reduction, or Orch OR for short. It’s a possible answer to what has been called the “hard problem of consciousness” in science, that is, the origin and nature of consciousness. Whence self-awareness? Do animals possess it to the extent that humans do? Do we have an inner essence or core—a soul? Is consciousness necessary to earthly life, even to the universe, or could life have flourished even if earth was populated solely by zombies? Orch OR also engages these and similar questions.

Its genesis began in Penrose’s 1989 book, The Emperor’s New Mind, a critique of strong Artificial Intelligence. Strong AI holds that the human brain is, in effect, a souped-up classical computer, one operating in binary logic, that is, with bits of opposing terms, such as yes/no, heads/tails, or north/south. On this view, humans are nothing special.

On the other hand, it could be that human brains are more quantum than classical, and thus crazy fast, capable of processing far more information than a classical computer can. The construction of a meaningful quantum computer is, according to Intel, “likely more than a decade away.” If one were ever built, however, it could do astonishing feats such as cracking all Internet security codes. As Charles Seife points out in his 2007 book Decoding the Universe, such computers would differ from classical ones in that they could hold two contradictory things in tension, or “superposition”; that is, yes and no, heads and tails, north and south. And they would only “decide,” or (in quantum-physics-speak) collapse the wave function at the last moment.

If Orch OR is correct, it would seem that the 21 grams notion isn’t that far off the mark after all. The soul may not have mass, but it can, in theory, be studied.So our ability to keep two conflicting possibilities in play when decision-making (steak or chicken, working out or loafing, speech or silence) may not be an accident, or mere procrastination; instead, it could be integral to how our brains work. Rather than trafficking in bits, the “alphabet” of classical computing, we may be wired for qubits, the currency of quantum computing that allows for both/and thinking.

At least, that was Penrose’s hunch. He posited that our brains are more than classical, in part because of his understanding of Austrian logician’s Kurt Gödel’s famous incompleteness theorems. (Here’s a brief refresher.) Gödel proved these in 1931. They show that all mathematical and logical systems worth their salt always have loose ends; they are always either incomplete or inconsistent.

Penrose raised the question, If Gödel’s theorems are true, how can they be proven? What’s to prevent them from undercutting their own logic? Aren’t they expressed in mathematical terms that are part of a math system that is itself imperfect and therefore unprovable? And yet, such uncertainty hasn’t been the result; instead, Gödel’s proposals are widely accepted and are now part of the mainstream study of math and logic. This fact prompted Penrose to wonder if such a transcendent, “God-given” view suggested that our brains were more than merely classical.

Still, he couldn’t identify a place in the brain for any quantum operation. The main challenge to quantum computing is decoherence, when information breaks down and leaks out. Quantum events seem to work fine in cold, isolated, subatomic settings, but in the real world, information’s just too fragile and has too many places where it’s leaking out. (This is the answer, by the way, to Schrödinger’s cat: if we and the cat could scale ourselves down to the quantum level, the paradox would hold, and the cat would be, weirdly, both alive and dead. But in the non-quantum world, the information about its status will be evident prior to our opening of the box. The cat’s relative largeness and softness means that it is constantly leaking information about its existential condition out into the world.)

It would seem that the human brain has the same problem—it’s just too big to retain and use quantum information. Alan Turing, in fact, likened this organ to a big, messy bowl of porridge. That organ utilizes neurons, yet as Seife points out, “[n]eurons… tend to behave just like classical devices that store and manipulate bits; if the brain is somehow storing and manipulating qubits, there must be another mechanism besides the neuron’s standard chemical bit flip that biologists are familiar with.”

After reading The Emperor’s New Mind, anesthesiologist Stuart Hameroff stepped forward and offered Penrose a mechanism: microtubules, tiny tubes in the brain composed of a protein called tubulin. Seife states that tubulin “makes up the skeletons of our cells, including neurons. What makes them interesting is their … potentially quantum role” (213). They can be both extended and contracted at one and the same time, “in a state of superposition” (213). Put another way, the microtubules might provide a site for the quantum brain. And, they might be the seat of—wait for it—the soul. Thus, Orch OR was born.

In presenting their theory, Penrose and Hameroff parted company with most scientists, the majority of whom posit that consciousness arose slowly by an evolutionary process, as neurons began firing, more and more, with one another. Orch OR, on the other hand, argues that consciousness arises not between, but within, microtubules, inside the neurons, where quantum events take place. As they become “orchestrated” with each other, they produce discrete, quantized moments of awareness, which, taken together, result in what we call consciousness—somewhat like a film, as many separate frames produce the illusion of a “moving” picture.

Perhaps the most interesting part of Orch OR is its inversion of common sense, in which consciousness is a localized phenomenon. We tend to regard consciousness as starting with the human subject and radiating outward; our brains evolve, and then we’re able to look beyond ourselves and perceive things. But Orch OR argues that in fact, there are quantum events happening outside of us, ones that become entangled with our brains, and which, as it were, spark or fire our consciousness. To quote Penrose and Hameroff, “There is a connection between the brain’s biomolecular processes and the basic structure of the universe.”

If Orch OR is correct, it would seem that the 21 grams notion isn’t that far off the mark after all. The soul may not have mass, but it can, in theory, be studied. In this stunning video, Hameroff remarks that “the soul is a real entity in terms of quantum information embedded in the universe.” He also claims that that information, because it’s quantum, experiences quantum entanglement (here’s “What the Physics” on entanglement) with things outside the body, and thus, in theory, could be reconstituted after death.

So the soul may not have weight, yet it may be physical. How? Let’s return to Hameroff’s claim about the soul’s composition. According to information theory, which posits that information is more fundamental to the universe than either matter or energy, information is immaterial, and yet is instantiated in physical objects. Its paradoxical character is perhaps best understood when we compare information to energy.

Energy too is immaterial, though of course it’s convertible to matter, per E = mc2. Yet energy, though weightless, is measureable, and clearly there. So too with information. Plus, as noted, quantum information is entangled: it reacts with and to its environment, and is thus capable of reconstruction after being seemingly lost or destroyed—even in the crushing force of a massive black hole.

What might a Christian make of Orch OR? Of course, we believe in the soul because it’s often referred to in scripture. Traditionally, Christians have taken various views on the soul. One, Traducianism, holds that the soul is intimately linked with the body, so that the soul is physically transmitted at the time of conception. Another is Creationism, which holds that God fashions and implants a new soul every time a person is conceived. The third major perspective equates the soul with our identities, our personhood; according to a theologian friend, a person, in this view, doesn’t have, but rather, is a soul, by virtue of that fact that that soul exists in relation to God.  This understanding is reflected when we say things like, “I didn’t know a single soul there.”

In this sense, then, 21 Grams is implicitly biblical, as scripture tends to regard the heart as the locus of identity.Whichever view we adopt, it might be asked, do we need science to bolster it? Particularly a theory like Orch OR, which is highly speculative, even suspect with certain scientists? For instance, the influential physicist Lawrence Krauss, after hearing a presentation on the concept, offered a withering assessment: “From a physics perspective… this is nonsense.” Indeed, Orch OR seems to have gotten more purchase with New Age mystics like Deepak Chopra than with scientists.

Then again, since the publication of Penrose and Hameroff’s work, the theory’s been getting more support from some quarters. As it turns out, quantum effects are not limited to the sub-atomic world, but have also been observed in phenomena such as plant photosynthesis, and quantum biologists have proposed that certain birds are able to navigate on their migrations by using quantum entanglement. As Christians, then, we don’t need science to prop up our beliefs, true, but we should at least be aware when scientists are working on something that overlaps with, and in some ways reinforces what we believe.

Interestingly, while 21 Grams would seem by its title to assume the soul’s existence, in fact the term “soul” is not used in Penn’s meditation on what happens to us at death. Could that omission suggest that Iñárritu and/or his co-writer Guillermo Arriaga regarded an explicitly spiritual term as clashing with the film’s stark, this-worldly atmosphere? It’s possible, though the movie doesn’t shy away from religious references when telling Jack Jordan’s story; he quotes scripture, is shown worshiping in church, and witnesses to an at-risk young man. He’s even told by his pastor that he’s in danger of losing his soul. Then again, Jordan’s religious faith doesn’t seem to help him much, and at one point he appears to abandon it. Perhaps, then, the screenplay does offer at least a partial critique of religion.

Yet if we regard the soul in terms of a person’s essence or identity, that notion is clearly present in 21 Grams, though it’s linked, not with the brain, but the heart. When Penn’s character aggressively seeks out the identity of the man whose heart was donated to him, even hiring a private detective to gain access to the necessary medical records, his puzzled wife asks him why he is pursuing this quest. He answers, “Mary, I want to know who I am.” It’s as if he’s hoping to become a new person—a new soul, perhaps—from the transplant.

In this sense, then, 21 Grams is implicitly biblical, as scripture tends to regard the heart as the locus of identity. Indeed, so close is the heart-soul linkage in the film that as I watched, I wondered whether it was inviting me not only to assemble the non-linear narrative, but also to ask whether the heart weighs somewhere near 21 grams. Not so, however; a quick check showed that they tend to measure around 100 grams. Then again, Penn’s meditation on what is lost at the time of death, which concludes the film, ends by asking, twice, “What is gained”? At that point the camera shows Christina Peck’s character, clearly pregnant. And of course most fetuses will weigh 21 grams at some point in their development. Here, then, the link of the soul with personhood is clear, both narratively and visually.

Summing up, 21 Grams offers an engrossing meditation on the mystery of the soul and the uniqueness of each person. The main characters lead lives that at times devolve into hot messes involving drug addiction, adultery, and manslaughter. Such grittiness instills the film with a cinematic soul, setting it apart from any number of vacuous blockbusters. Yet there is also a measure of redemption for each character, a fact that invites us to view all people, ourselves and others, as capable of a fuller sense of personhood, through relationship with—through entanglement with—the living God.