Scientists Dismissed a Theory of Consciousness for 40 Years. New Evidence Suggests They Spoke Too Soon.

3 min readHere’s what you’ll learn when you read this story:For nearly 40 years, scientists have debated whether some aspects of consciousness are non-computational, and therefore, quantum in nature. While regarded as controversial and fringe for decades, evidence hasn’t entirely refuted the theory, and its core ideas are generating more and more attention. Recent studies have provided compelling evidence that quantum processes, with microtubules in neurons serving as a substrate, play a role in human consciousness.The rise of consciousness in humans and all living beings is arguably the greatest wonder of the natural world—and it’s also one of its biggest mysteries. Over millennia, theologians, natural philosophers, and neuroscientists have put forward their own ideas about how this phenomenon arises within our minds, and by the tail end of the 20th century, one of these new theories raised more than a few eyebrows.This interest was warranted for a couple of reasons. First, the person proposing the idea was Roger Penrose, English mathematician and Nobel Laureate. And the second? Well, it involved the most devilishly complex of all scientific fields: Quantum theory. In his 1989 book The Emperor’s New Mind, Penrose theorized that consciousness couldn’t be entirely classical, and that it required non-computable physics. In collaboration with Stuart Hameroff, an anesthesiologist at the University of Arizona, Penrose went on to develop the theory of Orchestrated Objective Reduction, or Orch OR.For decades, neuroscientists largely dismissed Orch OR. One of the chief reasons was that the human mind seemed too warm and chaotic for quantum mechanics to play any meaningful role in consciousness. However, nearly 40 years after Penrose postulated his quantum theory of consciousness, the concept hasn’t faded away—in fact, recent scientific evidence may be making the theory even more appealing.One of the proponents of the Orch OR theory is Michael Wiest, a professor of neuroscience at Wellesley College. In recent studies published in the journals eNeuro and Neuroscience of Consciousness, Wiest laid out some evidence that bolsters the theory’s plausibility. Among the key biological structures in Orch OR are so-called microtubules (MTs), narrow tube-like structures found in cells throughout the body that take on specialized functions within neurons. In their 2024 eNeuro study, Wiest and his team introduced a binding chemical to the neuronal microtubules in rats. When the researchers then introduced anesthesia, the rats treated with the binding drug took longer to succumb to its effects, suggesting the drug was interfering with the anesthesia’s ability to impact those microtubules.“Our findings are consistent with similar but weaker effects reported in human surgery patients treated with MT-stabilizing anti-cancer drugs that penetrate relatively poorly into the brain,” Wiest wrote in an article last month for the Institute of Art and Ideas. “These results support the plausibility of MTs as the physical substrate of biological consciousness, and the evolution of consciousness from older cellular functions of MTs as integrators of sensory information and coordinators of movement.”In the article, Wiest also points to other breakthroughs, including the evidence of “quantum nonlocality” operating on macroscopic scales—work that eventually earned its researchers the Nobel Prize for Physics in 2022—as well as evidence of quantum entanglement signals in the brain.Despite Orch OR’s lasting power, the theory is still far from conclusive, and nearly as many studies have been published in the past year refuting the quantum theory of consciousness. One of those studies, published in The Journal of Neuroscience from scientists at MIT, posited that unified awareness arises from analog computations performed by electrical waves.“Electric field dynamics offer a low-overhead substrate for organizing and coordinating information across cortical networks,” the MIT researchers wrote in the study. “Given strong evolutionary pressure to maximize computation per unit energy, it would be surprising if evolution did not exploit such a built-in analog computing substrate.”For now, a theory of quantum consciousness remains a controversial idea, but time and time again, its core ideas remain difficult to refute.Watch Our Science VideosDarren lives in Portland, has a cat, and writes/edits about sci-fi and how our world works. You can find his previous stuff at Gizmodo and Paste if you look hard enough.