A few years ago, deep in the Apennines in Italy, a team of physicists hunted for flashes of light that could only suggest that human consciousness is a product of gravitational forces.
The fact that they came up empty-handed does not mean that we are all meat computers without free will; it makes the search for a suitable model that explains consciousness far more of a challenge.
If the idea of not having free will is unpleasant, 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 can introduce enough wiggle room for brains to break free from the “one input, one output” restrictions of classical mechanics.
While their hypothesis, called Orchestrated Objective Reduction (Orch OR), sits on the fringes of physics and biology, it is nevertheless complete enough to provide scientists with predictions that can be scientifically investigated.
“What I loved about this theory was that it is in principle testable, and I decided to search for evidence that could help confirm or falsify it,” said physicist Catalina Curceanu of the Laboratori Nazionali di Frascati in Italy.
Penrose’s and Hameroff’s concept may be testable, but it still rests on a mountain of assumptions about the way physics and neurology work at a basic level.
Fundamental to quantum mechanics is the notion that all particles exist as a series of possibilities unless they are somehow quantified by a measurement.
Exactly what this means is not clear, which leads some to interpret the difference as a “collapse” of the wave-like haze of perhaps into a concrete absolute of harsh reality.
Equally alluring is the question of why a swarm of possible values should settle on a measurement at all.
An idea advocated by Penrose and colleague Lajos Diósi in the late 20th century suggested that the curvature of space-time may favor some possibilities over others.
To put it another way, the mass and its gravitational force can somehow push quantum waves flat.
Using this assumption on competing quantum states of cellular material – namely tubulin that mixes chemicals around inside the neurons – Penrose and Hameroff calculated the time it would take for quantum effects to translate into mechanisms that would affect consciousness.
While their model stops far from explaining why you made a conscious choice to read this article, it shows how neurochemistry can deviate from classic computational operations to something less restrictive.
Penrose’s and Diósi’s gravity collapse site has been tested before, by none other than Diósi himself. Their experiment in the Gran Sasso National Laboratory examined the simplest collapse scenarios, and found no evidence that the hypothesis was accurate.
In light of these findings, the team now asks how their past results may affect Penrose’s 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 Diós’ previous experiments, it is very unlikely that gravity pulls the strings of consciousness.
At least not in this specific way.
“This is the first experimental study of the gravity-related quantum collapse column of the Orch OR consciousness model, which we hope will be followed by many others,” says Curceanu.
Exactly what it would mean if an investigation found a glimmer of evidence for Orch OR is hard to say. Non-computational descriptions of consciousness are not only difficult to study; they are challenging to define. Even indisputable programs that reflect human thinking challenge our efforts to discover examples of perception, self-awareness and free will.
Nevertheless, the idea that biological systems are too chaotic for delicate quantum behavior to emerge has weakened in light of the evidence that entanglement plays a role in functions such as navigation in birds.
Just maybe a glimpse of inspiration is all we need to set out to understand the physics of our soul.
This research was published in Physics of Life Reviews.