Do our minds have quantum structures that give rise to consciousness? Sir Roger Penrose, one of the world’s most famous scientists, believes this and can explain how it works.
The nature of consciousness, its occurrence in the brain, and its ultimate place in the universe are unknown. How can a structure such as the brain control all our actions and make us aware of the world around us since…
. . . it resembles nothing so much as a bowl of cold porridge. ~ Alan Turing
Prof. Roger Penrose’s thesis argues that human intelligence is far more subtle than ‘artificial intelligence’ in computers. Along with authors including the philosopher J. R. Lucas, he has debated the implications that the Incompleteness Theorems might have about the human intelligence. The debate centres around the idea that the human mind might be equivalent to a Turing machine, or by the Church–Turing thesis, any finite machine at all. If it is, and if the machine is consistent, then Gödel’s incompleteness theorems would apply to it.
“All aspects of mentality are merely features of the computational activity of the brain; consequently, electronic computers should also be capable of consciousness, and would conjure up this quality as soon as they acquire sufficient computational power and are programmed in an appropriate way.”
In his book, “The Emperor’s new Mind”, Sir Roger Penrose explains his disbelief in the usual foundations of consciousness, arguing how it cannot be explicable in computational terms. His reasoning starts by referring to the results of Gödel and Turing that mathematical thinking cannot be enclosed within any computational model of thought. Human consciousness is non-algorithmic, and thus is not capable of being modeled by a conventional Turing machine-type of digital computer. The second argument that Prof. Penrose proposes is the lack of connection between the submicroscopic world of quantum physics to the macro-world of classical physics. The collapse of the quantum wavefunction is seen as playing an important role in brain function.
After the publication of this book, Prof Penrose began to collaborate with Prof Stuart Hameroff on a biological analog to quantum computation involving microtubules, which became the foundation for his subsequent book, “Shadows of the Mind: A Search for the Missing Science of Consciousness”.
“A lot of what the brain does you could do on a computer. I’m not saying that all the brain’s action is completely different from what you do on a computer. I am claiming that the actions of consciousness are something different. I’m not saying that consciousness is beyond physics, either — although I’m saying that it’s beyond the physics we know now…. My claim is that there has to be something in physics that we don’t yet understand, which is very important, and which is of a non-computational character. It’s not specific to our brains; it’s out there, in the physical world. But it usually plays a totally insignificant role. It would have to be in the bridge between quantum and classical levels of behavior — that is, where quantum measurement comes in.” ~ Roger Penrose
The Penrose-Hameroff argument has three parts : the Gödel Part, the Gravity Part and the Microtubule Part.
The Gödel Part refers to Gödel’s Incompleteness Theorems in an attempt to prove that humans have intellectual abilities that are non-computable which they could not have if they they functioned in accordance with the principles of classical physical theory. Proving this would reaffirm a conclusion of the von Neumann formulation of quantum theory, namely, that a conscious human being can behave in ways that a classical mechanical model cannot.
Prof. Penrose’s suggestion and the other pillar (the Gravity Part) of his argument is that gravity is responsible for the fact that everyday objects, such as chairs and planets, do not display quantum effects. Penrose believes that quantum superpositions become impossible for objects much larger than atoms, because their gravitational effects would then force two incompatible versions of space-time to coexist.
The Microtubule Part argues the belief that consciousness is closely linked to the microtubular structure of the neuron.
Using Gödel’s Incompleteness Theorems to prove that our understanding is more than a computational action
What Gödel’s Incompleteness Theorems tell us is that suppose we are given some computational procedure P for establishing mathematical assertions (e.g. “Fermat’s last theorem”) and if we accept that the rules of P are trustworthy, then we must also accept as unassailably true some other assertion G(P) which is beyond the scope of the rules of P. As a result, once we have seen how to mechanize some part of our mathematical understanding, then we can also see how to transcend this mechanization. (you can read more about Gödel’s Incompleteness Theorems in my other article “An overview of Gödel’s incompleteness theorems”)
Down the Quantum Rabbit Hole
Prof Penrose’s argument lies in the basic properties of quantum computing, in which bits (qubits) of information can be in multiple states (e.g. in the “on” or “off” position at the same time). These quantum states exist simultaneously (known as superposition) before uniting into a single, almost instantaneous, calculation. Quantum coherence occurs when a huge number of things, for instance, a whole system of electrons act together in one quantum state.
It was Prof. Hameroff’s idea that quantum coherence happens in microtubules, protein structures inside the brain’s neurons. Microtubules are tubular structures inside eukaryotic cells (part of the cytoskeleton) that play a role in determining the cell’s shape, as well as its movements, which includes cell division. Prof. Hameroff suggests that microtubules are the quantum device that Prof. Penrose had been looking for in his theory. In neurons, microtubules help control the strength of synaptic connections, and their tube-like shape might protect them from the surrounding noise of the larger neuron. The microtubules’ symmetry and structure are of particular interest to Prof. Penrose as he believes this is where the quantum mechanics takes place.
But you would still need some sort of structure and orchestration to be able to make conscious decisions and according to the Penrose-Hameroff theory of Orchestrated Objective Reduction, known as Orch-OR, this kind of orchestration is conducted by the microtubules in the brain, which would have the ability to store and process information and memory.
“Objective Reduction” refers to Prof. Penrose’s ideas about quantum gravity — how superposition applies to different spacetime geometries — which he regards as a still-undiscovered theory in physics.
The qubits are based on oscillating dipoles forming superposed resonance rings in helical pathways throughout lattices of microtubules. These types of oscillations are either electric (due to charge separation from London forces), magnetic (due to electron spins or nuclear spins). Orchestration refers to the hypothetical process by which connective proteins, such as microtubule-associated proteins influence or orchestrate qubit state reduction by modifying the spacetime-separation of their superimposed states. The latter is based on Penrose’s objective-collapse theory for interpreting quantum mechanics, which postulates the existence of an objective threshold governing the collapse of quantum-states, related to the difference of the space-time curvature of these states in the universe’s fine-scale structure.
There has been quite a lot of criticism in the scientific community and most of it concentrates on three issues: Prof. Penrose’s interpretation of Gödel’s theorem; Prof. Penrose’s abductive reasoning linking non-computability to quantum processes; and the brain’s unsuitability to host the quantum phenomena stated by the theory (as the brain is considered to be too warm, wet and noisy to be able to avoid decoherence.)
To be able to build a quantum computer, you need to connect qubits in a process called entanglement. The problem is that entangled qubits exist in a complex and fragile environment where they must be protected from any noise in the surrounding environment, which would make it a difficult, nearly impossible process to happen in the human brain.
Some evidence has been produced in recent years where warm quantum coherence was proved to exist in the photosynthesis of plants, bird brain navigation, our sense of smell and even in brain microtubules. Furthermore, the discovery of quantum vibrations in microtubules by Anirban Bandyopadhyay of the National Institute for Materials Science in Japan in March 2013 confirms the Orch-OR theory and states that EEG rhythms also derive from deeper level microtubule vibrations. Penrose and Hameroff argue that vibrations of microtubules can adopt a quantum superposition.
In a study published in 2015, physicist Matthew Fisher of the University of California at Santa Barbara argued that the brain might contain molecules capable of sustaining more robust quantum superpositions. Specifically, he thinks that the nuclei of phosphorus atoms may have this ability. The process can be described in short as follows:
- The biological molecule adenosine triphosphate can release pyrophosphate, made from two phosphate molecules.
- Each phosphate carries a quantum spin, and the two phosphates can become entangled with each other.
- Unprotected, the phosphate entanglement will decay, or decohere.
- But if the phosphates are grouped together into protective clusters called Posner clusters, which are made of phosphate and calcium ions, the entanglement might survive for a longer period of time.
- If a pair of entangled phosphates split into different Posner clusters, they will remain entangled even as the clusters transport them from each other. In this way, the entanglement can be distributed over fairly long distances in the brain. This allows for the possibility of a quantum basis for a brain function.
After twenty years of criticism, there is now evidence that supports orchestrated objective reduction. The Orch-OR is said to be the most comprehensive and successfully tested theory of consciousness ever brought before us.