One of the most important and puzzling open questions in science is how our consciousness comes about and functions. In the 1990s, before winning the 2020 Nobel Prize in Physics for his predictions of black holes, physicist Roger Penrose teamed up with anesthesiologist Stuart Hameroff to propose an ambitious answer.
They claimed that the brain’s neuronal system forms an intricate network and that the consciousness this produces should obey the rules of quantum mechanics, the theory that determines how tiny particles like electrons move around. This, they argue, could explain the mysterious complexity of human consciousness.
Penrose and Hameroff were met with a lot of skepticism . Quantum laws are usually only found to apply at very low temperatures. Quantum computers, for example, currently operate at around -272°C. At higher temperatures, classical mechanics takes over.
Since our body is warm, you would expect it to be governed by the classical laws of physics. For this reason, the quantum consciousness theory has been dismissed outright by many scientists and researchers.
Our brains are composed neurons, and their combined activity is believed to generate our perception of individual consciousness. Each neuron contains structures called microtubules, which transport substances to different parts of the cell. The proposed theory of quantum consciousness argues that microtubules are structured in a fractal pattern which would enable quantum processes to occur.
In geometry, fractals emerge as patterns that repeat themselves infinitely, generating what is sounds bizzare and impossible: a structure that has a finite area, but an infinite perimeter.
Fractals actually occur frequently in nature, as the same basic shape repeating itself over and over again, but at smaller and smaller scales. That’s a key characteristic of fractals. The same happens if you look inside your own body: the structure of your lungs, for instance, is fractal, as are the blood vessels in your circulatory system.
We’re not yet able to measure the behavior of quantum fractals in the brain, if they exist. But advances in technology means researchers can now measure quantum fractals in the lab.
Microscope techniques cannot probe how quantum particles move, which would tell us more about how quantum processes might occur in the brain. But experiments reveal that quantum fractals actually behave in a different way to classical ones. Specifically, its been discovered that the spread of light across a fractal is governed by different laws in the quantum case compared to the classical case.
This new knowledge of quantum fractals could provide the foundations for scientists to experimentally test the theory of quantum consciousness. If quantum measurements are one day taken from the human brain, they could be compared to definitely decide whether consciousness is a classical or a quantum phenomenon. Hopefully this will happen some time in the future, but until then, the nature of consciousness will remain a mystery.