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Quick notes:

  • Some scientists are trying to explain the mysterious phenomenon of consciousness with quantum physics — the study of small systems that behave more like waves of possibilities than predictable events.
  • There are various theories about how quantum processes could cause consciousness, but none of them are scientifically proven.
  • We do know there are quantum processes in the brain that affect how it works, but that’s not specific to consciousness itself.

Consciousness has been a puzzle for scientists and philosophers since the days of Plato. While some neuroscience research has identified brain activity that correlates with conscious thought, it still remains a mystery how a series of electrochemical changes in our brain cells can lead to subjective experiences like perceiving colors or feeling emotions. 

“We don’t know why neural tissue gives rise to thought,” says neuroscientist Izi Stoll, director of the Western Institute for Advanced Study. “We know it’s a feature of neural networks. We know the mind exists. There are materialists who say we are nothing more than bodies and there’s nothing more to it, so people will publish books saying the mind is an illusion, but it’s an illusion we all have.” 

So far, most theories of consciousness have come from cognitive science, which offers handy metaphors for how consciousness works — for example, one theory says the mind is like a stage and consciousness is like the spotlight — but they don’t tell us what causes it, says Stoll. 

For scholars looking to scientifically explain what might physically give rise to the conscious awareness everyone seems to have, quantum physics — the study of small systems that behave like waves of possibilities, rather than predictable events like the large-scale things humans perceive — has seemed like a natural area to investigate. After all, the things that take place in the world of quantum mechanics are perhaps just as mysterious as consciousness itself. Subatomic particles that exist in two places at once? Electrons that behave differently when they’re observed? A cat that’s both alive and dead? If anything can explain seemingly ethereal phenomena, perhaps it’s this. 

Just as people are hoping quantum physics might shine light on the mystery of consciousness, some are hoping consciousness can help solve the mystery of quantum physics, says Lesley L. Smith, a physicist at the University of Colorado. Quantum physics has an “infinity problem” — the fact that its equations have infinite states — and integrating quantum theory into a larger theory of consciousness might help explain why we as humans experience one reality and not infinite realities, Smith explains.

As you might expect, scientists and philosophers have come up with a number of different theories for how quantum physics might shine light on consciousness. Perhaps the most well known was put forth by physicist Roger Penrose and anesthesiologist Stuart Hameroff in 1989. They drew from the Copenhagen interpretation of quantum mechanics, which states that quantum particles can be in two states at once until a human observes them, and then the “wave function” representing these different possibilities collapses into one reality. In contrast, their theory proposed that wave-function collapse could occur due to intrinsic constraints in the physical system itself. While scientists have traditionally postulated that human consciousness determines the outcome of a quantum event, Penrose and Hameroff proposed that wave function collapse actually causes consciousness. 

Albert Einstein theorized that the forces placed on physical matter in the universe are a result of curvatures in space-time geometry. Penrose and Hameroff extrapolated that it’s this space-time curvature that causes certain events to occur at the quantum level, and these events affect quantum particles within tiny structures that make up brain cells’ cytoskeletons, called microtubules, which are responsible for consciousness. They drew from research suggesting that anesthetics, which lead to a loss of consciousness, act on microtubules. 

While interesting, this theory isn’t widely accepted by the scientific community. One issue is that the evocation of microtubules as the source of consciousness brings up more questions than it answers, says Stoll. “Every cell in your body has microtubules in it, so there’s no reason that events occurring in microtubules could give rise to consciousness in neurons but not other cells in your body,” she explains. “There are microtubules in every one of your liver cells. Why isn’t your liver conscious?” 

Close-up of an axon with cell body, terminal, synaptic cleft, and dendrite. Nerve cell projection or neuron (VectorMine/iStock/Getty Images Plus)

Another argument made against this theory is that the quantum states in the brain that may come about due to the nature of microtubules wouldn’t last long enough to produce neural processes leading to consciousness, says Smith. 

An alternative theory put forth by biologist Johnjoe McFadden and neurophysiologist Susan Pockett, known as conscious electromagnetic information (CEMI) field theory, states that when neurons harness the motion of charged particles to send electrical signals, the electromagnetic field they produce constitutes consciousness. This theory predicts that transcranial magnetic stimulation — the stimulation of nerve cells using magnetic fields, which is sometimes used to treat depression — should elicit a change in the conscious mental state, Stoll explains. This does occur, but since there are many reasons it could be happening, it’s still unclear exactly how neural activity generates mental states. “The problem with that theory is that it is really vague,” she says. “It does not make many specific predictions about the physical processes that relate brain cells to consciousness.” 

Lastly, a concept known as brain-mind operational architectonics, developed by neuroscientists Andrew and Alexander Fingelkurts, postulates that water molecules of the brain create a “cortical field,” which interacts with quantum waves that propagate through brain cells, producing consciousness. However, the theory appears to draw largely from Eastern metaphysics rather than scientific evidence alone; its proponents state, “We aim to show that the brain-mind OA is the boundary between and integration point of quantum physics and Eastern metaphysics, and that it may inspire building a richer and more inclusive paradigm of the brain-mind relation, where quantum physics and Eastern metaphysics are inherently intertwined.”

That doesn’t mean quantum operations aren’t involved in consciousness, though. In fact, quantum operations are involved in every biological process. “Quantum operations occur in every biophysical system. So, if quantum operations are involved in the functions of subatomic particles, and we know that the brain is made of molecules that are made of atoms that are composed of subatomic particles and structures that are able to obtain quantum processes, yes, there are quantum processes in the brain,” says James Giordano, professor of neurology and biochemistry at Georgetown University Medical Center. “It’s possible that there may be some preservation of quantum-like effects on a very small scale that are contributory to mechanisms of consciousness.”

However, when you look at phenomena like consciousness that appear to involve large networks of neurons, these behave like large-scale, Newtonian systems, not quantum systems, Giordano explains. 

The one thing that may be significant about brain cells is that they have been shown to form specialized functional clusters, called cliques, that allow for 11 dimensions of connectivity, Giordano says. This means they could be processing information through myriad vectors and in ways not previously understood or appreciated. And the more dynamic and multi-scale dimensions a system uses, the greater the possibility that quantum-like properties of that system may be preserved in some ways in and across scales. Still, this is more of a mathematical property of the brain more generally, not consciousness in particular, says Giordano. There isn’t any evidence that consciousness is special in this regard.

“The bottom line is, we don’t actually know what’s going on (with quantum physics), which is the same thing with consciousness: we don’t quite understand how it works,” says Smith. 

So, there hasn’t really been a quantum physics-based theory that explains consciousness — yet. But Stoll still believes there could be someday. “What we really need for a quantum theory of consciousness — or any theory of consciousness — is a theory that really rigorously takes into account the mathematics of quantum mechanics and provides a conceptual framework around that,” says Stoll. “Following the mathematical formalism of physics and making predictions that can be tested by experimentalists is the key to making progress here.” This melding of fields is still in its infancy, so, scientists, get on it. 

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