A few years ago, deep beneath the Apennines in Italy, a team of physicists searched for flashes of light that might indicate that human consciousness is the product of gravitational forces.
The fact that they showed up empty-handed doesn’t mean we’re all flesh computers with no free will; however, it makes finding a suitable model to explain consciousness far more challenging.
If the idea of not having free will is uncomfortable, you are not alone. In the 1990s, Nobel laureate Roger Penrose and an anesthesiologist named Stuart Hameroff argued that the quantum properties of cellular structures called microtubules might provide enough leeway for the brain to free itself from the limitations of classical “one entrance, one…” mechanics exit”.
Although their hypothesis, dubbed Orchestrated Objective Reduction (Orch OR), sits on the fringes of physics and biology, it is still complete enough to provide researchers with predictions that can be scientifically examined.
“What I loved about this theory was that it is testable in principle, and I decided to look for evidence that could help confirm or falsify it,” says physicist Catalina Curceanu of the Laboratori Nazionali di Frascati in Italy.
Penrose and Hameroff’s concept may be testable, but it still rests on a mountain of assumptions about how physics and neurology work at the fundamental level.
Fundamental to quantum mechanics is the notion that all particles exist as a set of possibilities unless quantified in some way by a measurement.
Exactly what this means is not clear, leading some to interpret the difference as a “collapse” of the wavy veil of maybes into a concrete absolute of harsh reality.
Equally intriguing is the question of why a swarm of possible values should settle on a measurement at all.
An idea put forward by Penrose and his colleague Lajos Diósi in the late 20th century suggested that the curvature of spacetime might favor some possibilities over others.
In other words, mass and its gravitational pull could somehow flatten quantum waves.
Penrose and Hameroff applied this assumption to competing quantum states of cellular material — namely, the chemicals that mix tubulin inside neurons — and calculated the time it would take for quantum effects to be translated into mechanisms that would affect consciousness.
While their model is far from explaining why you made a conscious decision to read this article, it does show how neurochemistry can deviate from classical computational operations to something less restrictive.
Penrose and Diósi’s gravitational collapse idea had not been tested before by none other than Diósi himself. Their experiment at Gran Sasso National Laboratory examined the simplest collapse scenarios and found no evidence that the hypothesis was correct.
Given these findings, the team is now wondering how their earlier findings might impact Penrose and Hameroff’s Orch-OR hypothesis.
Their critical analysis of the model suggests that at least one interpretation of the hypothesis can now be ruled out. Given what we know about quantum physics, the distribution of tubulin in our neurons, and the limitations imposed by Diósis’ previous experiments, it’s extremely unlikely that gravity is tugging at the strands of consciousness.
At least not in this particular way.
“This is the first experimental investigation of the gravity-related quantum collapse pillar of the Orch-OR model of consciousness, which will hopefully be followed by many more,” says Curceanu.
Exactly what it would mean if an investigation found evidence of Orch OR is hard to say. Non-computational descriptions of consciousness are not only difficult to study; they are difficult to define. Even undeniable programs that reflect human thought challenge our efforts to identify examples of sentience, self-awareness, and free will.
But the notion that biological systems are too chaotic for sensitive quantum behavior to evolve has been weakened in the face of evidence that entanglement plays a role in functions like navigation in birds.
Perhaps just a flash of inspiration is all we need to set us on the path to understanding the physics of our souls.
This study was published in Physics of Life reviews.