Letters to the Editor—Alternate Perceptions Magazine, November 2018
Thanks so much for your April AP issue. I especially enjoyed your Reality Checking review of the March Discover magazine article Down the Quantum Rabbit Hole. As you noted, the question of consciousness, of its ultimate nature and origin, is certainly one of the new frontiers in modern physics. The connection between the two has been hypothesized from the earliest years of quantum mechanics. Now, physicists are collaborating with biologists, neuroscientists, computer scientists, and other disciplines to try to decipher the mystery of consciousness.
Sir Roger Penrose has stated in some of his books that quantum physics can help neuroscience better understand consciousness. What I've learned from researching the ideas I'm developing in the overview of my book Subtle Realms: The Jung-Pauli Search for the Nature of Reality: Time, Causality, and the Linear Mind is that Penrose's claim is true but, conversely, and even more importantly, I believe, is that neuroscience can provide critical assistance in explaining the gaps in understanding between micro and macro-level physics, particularly in regard to the quantum measurement problem which I’ll address near the end of this email.
You did a beautiful job explaining the ideas espoused by Penrose and Hameroff and their theory of microtubules as a driving force of consciousness. A number of questions came to mind when reading your article. To find answers, I thought it might be helpful to read the original Discover piece. After doing so, I was left with even more questions. I think most of these questions stem from the various notions of consciousness which abound in scientific and lay communities. It's difficult talking about consciousness when it means different things to different people.
Although not explicitly stated, the researchers interviewed or mentioned in the Discover article seemed to view consciousness as a kind of cognitive or information-processing function or, at an even more elementary level, as a state of simply being awake as opposed to asleep or comatose. For most of us, though, consciousness is synonymous with awareness of self and one's relationship to the external environment; with a sense of one's own existence; and with reflective thought. To many, it is believed to transcend death as you mentioned in Reality Checking. To others, it is a force or energy which imbues the universe. It occurred to me halfway through writing this email that I should practice what I preach and define how I plan to use the term. For the sake of limiting the scope of my argument addressing what I believe are the limitations of the Penrose-Hameroff theory, consciousness will be used to mean self-awareness unless otherwise stated.
The author of Down the Quantum Rabbit Hole, Steve Volk, provides many helpful photographs and schematics to explain how microtubules and quantum physics may be the basis of consciousness. This leads to the initial question I had when reading your article: specifically, how microtubules facilitate conscious awareness. Volk states that the Penrose-Hameroff theory postulates that "consciousness originates from microtubules and actions inside neurons, rather than the connections between neurons". Stuart Hameroff has speculated, however, that the single-celled paramecium has rudimentary consciousness but no neurons which seems inconsistent with their theory. So, I'm wondering which cells and their associated microtubules are involved in the process? Are neurons the only ones or can any type of cell potentially facilitate consciousness? If neurons are the only cells involved, where do they reside? Do only cortical neurons facilitate consciousness?
In any case, I would argue that a paramecium is not capable of self-awareness or information-processing as we humans know it. What appears to be decision-making is actually a stimulus-response reaction to its environment. That said, the paramecium is undoubtedly a fascinating entity in its own right. I am wondering how a paramecium can respond to its environment if it contains no neurons unless it itself is a neuron, not like those in more sophisticated life forms yet still capable of performing basic survival activities. The cilia may function as pseudo axons and/or dendrites, conveying information from the environment to the cell body, while the cell body performs basic activities such as metabolism and reproduction just as cells in higher life forms do. Although the paramecium may be a bit of a mystery, we do know that as organisms become more highly evolved, differentiation of body parts increases to support diverse functions beyond those needed for survival. Very simple organisms require fewer specialized parts. A limited number of cell structures can serve multiple functions, allowing single-celled organisms to be fully self-contained and function on auto-pilot. This is merely an interesting aside, however. So, moving on …
From everything neuroscience has learned to date, self-awareness and sensory perception can only be experienced as such in the brain's cerebral cortex. An electrical impulse must travel from the sensory receptor where it originates to various cortical structures, sometimes quite distant, where it finally culminates in conscious awareness in the prefrontal cortex. Here, along with support from neural feedback loops with memory and emotional centers in the limbic system, the electrical signal is integrated with other signals from the same and different receptors to provide context, meaning, interpretation, association, and timing. These impulses must be transported from neuron to neuron across numerous synaptic junctions on their way to prefrontal and other cortical structures. So, from the standpoint of neuroscience, neuronal connections do matter. If electrical signals cannot be transported across synaptic clefts, they will not reach the cerebral cortex where they are experienced as meaningful sight, sound, taste, pain, and other sensations.
This leads to my next question regarding the Penrose-Hameroff theory of consciousness: What is it about neurons in the cerebral cortex that facilitates self-awareness? Does consciousness arise spontaneously in these neurons without interaction with other neurons as the Penrose-Hameroff theory would suggest? Doesn’t our sensory apparatus play a role in the development of consciousness? If we were deprived of our basic five senses and a sixth, proprioception, would we still be self-aware? Would we be capable of self-reflection? Would we know we exist? Would the concept of existence even be meaningful?
As you noted, Hameroff, an anesthesiologist, believes that the key to consciousness lies in the field of anesthesiology. He noticed that the brain functions of an anesthetized patient continue more or less as they normally would, that neurons continue to fire, and pain signals travel their normal paths. I question how he knows that. Has he observed or recorded these pain signals as they traverse the distance to the prefrontal cortex where they are experienced as pain?
Normally, only a tiny fraction of electrical signals are able to complete their journey from sensory receptors to the cerebral cortex. The transmission of an electrical impulse from neuron to neuron across synaptic junctions can fail anywhere along the sensory pathway, even in the prefrontal cortex and other cortical structures. Appropriate neurotransmitters must be present in the correct mix and balance to convey the tiny, delicate electron across the gap to the next neuron.
There are also brain structures which can suppress the transmission of electrical signals in a process called sensory gating. The gating mechanism serves an important function in mental health. It acts like a filter, ensuring that the conscious mind is not flooded with noise from extraneous or overwhelming sensory input. Two disorders which currently receive major research funding, autism and schizophrenia, are believed to be caused in part by the breakdown of sensory gating. Without sensory gating, our normal conscious lives would be overwhelmed with visual, auditory, olfactory, pain and other stimuli including motor impulses.
This normal modulation of sensory and motor signals may provide insight into how general anesthesia works and fails to work in the situation where a patient is believed to be anesthetized but is actually fully conscious and experiencing pain during surgery. In this latter situation, the patient is paralyzed (from a paralytic component of the anesthesia) and cannot cry out to alert the anesthesiologist.
This filtering process is important because it is the means by which sensory and motor input is single-threaded through sensory and motor pathways, preventing everything from happening at once. It separates a quantum flood of simultaneity into a linear, step-by-step progression of one signal followed by another. The end product of this process is what neuroanatomists call the linear mind. The fact that events are serially created in the conscious mind forms the basis for our notions of time and causality and the forward arrow of time.
Another neurological phenomenon which further focuses attention and limits our view of reality is called neuronal pruning. This process involves the mass die-off of fetal brain cells beginning one or two months before birth and continuing for a month or so after. Pruning also occurs during adolescence and early adulthood. The purpose of pruning is to eliminate neurons which fail to form appropriate connections or form no connections at all. In this process, targeted neurons are gobbled up by phagocytic immune cells. Sometimes pruning can go awry and certain neurons are eliminated which shouldn’t be or too few or too many neurons are eliminated. Post-mortem examination of brain tissue of schizophrenics has revealed a marked loss of gray matter and fewer neural connections (signs of inappropriate pruning) in the prefrontal cortex. Inappropriate neuronal pruning is also implicated as a possible cause of autism.
Sensory gating and neuronal pruning create the linear mind which determines the scope and nature of reality as we humans, and probably all mammalian, avian, and even lower forms of life, generally perceive it. This concept is important because it addresses what I believe is the weakest leg of the Penrose-Hameroff theory of consciousness: the role played by quantum activity inside a neuron’s microtubules which is thought to be the impetus for consciousness. According to the Discover article, Penrose and Hameroff have proposed that the collapse of all possible quantum states of an electron into a single state inside a neuron produces a conscious moment. To assess the plausibility of this theory, we need to understand what is meant by a quantum state and how the hypothetical collapse is thought to work. What I’m going to discuss next is probably stuff you already know but which I need to put out on the plate to support why I think the Penrose-Hameroff theory misses the mark.
A quantum state is a set of attributes describing an isolated quantum system such as an electron at any point in time. The set of attributes consists of the following quantum variables: position in 3 dimensional space, momentum, angular momentum, energy, and spin. These attributes can be expressed as a set of quantum numbers which define a particular state of a particle. A particle can have many possible quantum states and it exists in all of its states simultaneously. This property is known as superposition.
A measurement can be taken in a classical experimental setting to determine the specific quantum state of a particle at a given moment in time. However, because of difficulties inherent in measuring a quantum particle in a classical setting, mathematically described in the Heisenberg uncertainty principle, a precise determination of a quantum state can never be achieved. The conundrum associated with such a measurement is that as one attribute, say location, becomes well-defined, another attribute, say momentum, becomes less well-defined. At best, the measurement can only predict the probability of a particle being in any particular state at any given time. A series of measurements can be taken to produce a probability distribution of quantum states as the quantum system evolves over time. This probability distribution is described by Schrödinger’s wavefunction equation mentioned in the Discover article.
After Schrödinger developed his equation in 1926, the concept of wavefunction collapse was added by other physicists to account for what investigators find in the classical experimental setting. In this hypothesis, the constantly fluctuating probabilities associated with the quantum state of a particle are believed to collapse into a single probability corresponding to a specific set of attributes associated with the particle when it is measured or observed. Quantum position can be used to illustrate this principle. In its natural setting, a particle exists everywhere at once in a potentially infinite number of locations. When a particle is subjected to measurement or observation, the probabilities associated with all possible locations comprising its wavefunction appear to collapse into a single probability that the particle now exists in a specific location corresponding to what is seen or measured.
Although the concept of wavefunction collapse is routinely taught by educators and espoused in popular books on quantum mechanics, it is by no means universally accepted as representing what actually happens at the quantum level. This brings us to the quantum measurement problem I mentioned earlier in the second paragraph of my email. This problem arose from questions regarding how the hypothetical collapse actually works. Since the Schrödinger equation does not hypothesize wavefunction collapse and assumes that a particle will be in any number of mutually-exclusive states simultaneously, what occurs during measurement to induce the hypothetical collapse? What is special about the measurement procedure that causes the particle to cease existing in all its possible states? The ambient environment of a particle normally includes many things: people, furniture, equipment, movement of other things in its environment, particularly other particles with which it interacts including photons and dark matter and dark energy. Presumably, these interactions do not cause the quantum states of the particle to collapse so why should observation or measurement? More importantly, attempting to capture a specific quantum state from the rapidly fluctuating probabilities using relatively sluggish classical measurement procedures could never truly reflect the attributes at a given point in time. And finally, what happens to the other quantum states after the supposed collapse?
Many innovative theorists in quantum mechanics have rejected the theory of collapse. Besides Schrödinger, others included John Wheeler and two of his graduate students, Richard Feynman and Hugh Everett, at Princeton’s Institute for Advanced Study. A number of alternate theories have been proposed to better describe what actually happens at the quantum level.
I think the collapse hypothesis became popular because it is intuitive and an easy way around the measurement problem. I do not believe it accurately describes what is really happening at the quantum level, however. Rather, it reflects what appears to be happening in the human mind. I believe that quantum states do not collapse into a single state when measured or observed and that the particle still exists in all possible states just as it did before measurement. Just because the other states are not measured or simultaneously perceived by a human being, does not mean they don’t exist. Here’s an example, again using the quantum attribute of location, to illustrate what I mean:
From the perspective of the human observer doing the measurement, the particle ends up in location x, y, z at the moment the measurement occurs. From the perspective of the particle, anthropomorphically-speaking, it still exists simultaneously in all locations in which it had ever existed, currently exists, and ever will exist – in other words, without regard to time. That is why mutually-exclusive states can exist simultaneously in the quantum realm: because at this level, time does not exist, it is not a constraint, and mutual exclusivity is an illusion imposed by the human mind.
It seems to me that physicists who espouse the collapse hypothesis are looking at particle behavior from the perspective of classical physics, not quantum mechanics, and that the collapse of all possible quantum states into one occurs only at the macro level in the mind and instrumentation of the observer. In the collapse hypothesis, the behavior of a particle is being forced into a classical mold. I would agree that the acts of observation or measurement, the presence of measuring instrumentation, or even the human mind do change the particle’s behavior as we know it at the macro level and as it is measured, but not intrinsically. By definition, measurement or observation must occur at the macro level since the investigator and equipment exist at that level. Wavefunction equations were designed to formalize what is observed in the real world of macro-level objects and behavior.
I think some of the issues expressed in the quantum measurement problem arise from the inherent difficulty of conducting quantum experiments in a classical setting, of attempting to bring quantum behavior up to a level where it can be analyzed by human perception. Experimenters must contend with the fact that the quantum realm is fundamentally random and acausal and the universe is nonlocal, quite different from the way the human brain perceives matters. Probability is not meaningful at the quantum level. It is a classical methodology used to predict the evolution of a particle’s state as perceived by a human observer in a time-based framework.
This brings us back full-circle to the linear mind and the huge limitations it imposes on our study of quantum behavior and the quest to understand consciousness. Even if the collapse hypothesis were true, the Penrose-Hameroff theory, as outlined in the Discover article, does not explain specifically how the collapse creates consciousness. That question has not been answered.
Antonio Damasio, Professor of Neurobiology at the University of Southern California and author of several popular books including Descartes’ Error, has specifically addressed Roger Penrose’s theory of consciousness. In the December, 1999 issue of Scientific American, he has this to say in an article titled How the Brain Creates the Mind:
The quantum level of operations might help explain how we have a mind, but I regard it as unnecessary to explain how we know that we own that mind – the issue I regard as most critical for a comprehensive account of consciousness.
I apologize for my lengthy reply to your excellent article. I’ve consumed a lot of time explaining why I don’t agree with the Penrose-Hameroff theory of consciousness but haven’t offered much in the way of my own insight to the problem. I suppose I have a fairly generalized view of consciousness as it relates to quantum theory. It is my understanding that quantum activity underlies everything in the universe – animate and inanimate; animal, vegetable, and mineral – not just the few quantum-level biological, chemical, and physical processes we’ve discovered at the classical level. Quantum life is universal; it is everything, everywhere simultaneously, beyond time. It is the foundation of the universe as we currently understand it.
On that note, I am reminded of the response the current historical Buddha, Siddhartha Gautama, gave to his cousin Ananda when asked about the possibility of a supreme being. Gautama Buddha’s reply has been paraphrased thus:
There is, Ananda, the unoriginated, undifferentiated, unconstituted which is ultimately unknowable.
Consider the meaning of those words – unoriginated: comes from nowhere, has no beginning, has existed from all eternity; undifferentiated: cannot be broken into parts; unconstituted: unformed, composed of nothing, not created or equivalent to something else. In my view, this is a perfect description of consciousness, in the broader sense, and possibly even quantum reality.
Perhaps the quantum realm itself is consciousness and the narrower our focus in trying to understand it, the further removed we become from grasping its true meaning. That said, self-awareness is definitely part of the equation and easier to get a handle on. I love the definition of consciousness I found in the book The Serpent Power by Arthur Avalon, the pen name of Sir John Woodroffe, an early twentieth-century scholar of shaktic and tantric thought. Woodroffe states that consciousness is “the power of matter to know itself”. The thought of matter in this context is striking. It is so amazing because that’s what we are – vibrating, spinning particles imbued with a mind that is self-reflective and self-aware, bounded by its invention of time!
I am haunted by one of Jill Bolte Taylor’s quotes in her book My Stroke of Insight. Jill is a neuroanatomist who experienced a massive hemorrhage-induced stroke in her left cerebral hemisphere while preparing to leave for work at the Harvard Brain Tissue Resource Center. She describes how this stroke caused her brain to function non-linearly and what it was like living in this state. In her words:
And here, deep within the absence of earthly temporality, the boundaries of my earthly body dissolved and I melted into the universe.
How close does that come to experiencing Universal Consciousness?!!
Before closing, I’d like to credit a few of the sources I’ve relied on to formulate my ideas regarding the interconnection of neuroscience and quantum mechanics. I see these two disciplines fitting together like two pieces of a jigsaw puzzle. They interlock perfectly. A complete understanding of one cannot be achieved without a full understanding of the other, just like Niels Bohr’s concept of complementarity.
Here are some of my sources:
Brian Greene, The Fabric of the Cosmos
John Ratey, A User’s Guide to the Brain
Jill Bolte Taylor, My Stroke of Insight
Stanford Encyclopedia of Philosophy – Philosophical Issues in Quantum Theory
Journals such as Scientific American, Nature, Science, Current Biology
Online university courses in quantum mechanics
Online university courses in neurology and neural pathways
Abstracts for research grants on neurological problems associated with sensory gating
Roger Penrose, Shadows of the Mind
Roger Penrose, The Road to Reality
I must say how impressed I am with the writings of Roger Penrose. He writes with humility and an easy style, not aggressively pushing his ideas. He has stated on numerous occasions that Einstein’s classical theories of special and general relativity are on solid ground. They have stood the test of time and continue to be verified experimentally. Conversely, he believes that quantum mechanics has a long way to go before it can be fully understood. He is disturbed with the gaping holes in quantum theory and feels that many of the theoretical underpinnings may end up being reworked. I very much agree with his philosophy and believe that the inherent difficulties of trying to study quantum behavior at the macro, classical level are the root of some of these problems. The quantum measurement problem is a case in point.
Thanks for your patience and all the great articles you’ve sent our way. They’ve certainly been an inspiration for thought on my part. Take care.