2018, Farrar, Straus and Giroux, 274 pages
How do neurons turn into minds? How does physical “stuff”–atoms, molecules, chemicals, and cells–create the vivid and various world inside our heads? The problem of consciousness has gnawed at us for millennia. In the last century, massive breakthroughs have rewritten the science of the brain, yet the puzzles faced by the ancient Greeks remain. In The Consciousness Instinct, the neuroscience pioneer Michael S. Gazzaniga weaves together the latest research and the history of human thinking about the mind, giving a big-picture view of what science has revealed about consciousness.
The idea of the brain as a machine, first proposed centuries ago, has led to assumptions about the relationship between mind and brain that dog scientists and philosophers to this day. Gazzaniga asserts that this model has it backward: brains make machines, but they cannot be reduced to one. New research suggests the brain is actually a confederation of independent modules working together. Understanding how consciousness could emanate from such an organization will help define the future of brain science and artificial intelligence, and close the gap between brain and mind.
Captivating and approachable, with insights drawn from a lifetime at the forefront of the field, The Consciousness Instinct sets the course for the neuroscience of tomorrow.
Michael S. Gazzaniga
is the director of the SAGE Center for the Study of the Mind at the University of California, Santa Barbara. He is the president of the Cognitive Neuroscience Institute, the founding director of the MacArthur Foundation’s Law and Neuroscience Project, and a member of the American Academy of Arts and Sciences, the National Academy of Medicine, and the National Academy of Sciences. He is author of many popular science books, including Tales from Both Sides of the Brain.
The Consciousness Instinct: Unraveling the Mystery of How the Brain Makes the Mind
Contrasting Viewpoints on Consciousness
Gazzaniga starts by outlining the major theories on consciousness. There are the reductionists and materialists (e.g. Freud and Galen) that believe that mental states and consciousness arise from material interactions between neurons, atoms, and molecules. The reductionist and materialists are deterministic in outlook. Determinists believe that the future follows rigidly or is “determined” by the past. Behaviorists, such as Skinner, form a subset of this worldview.
Then, thanks to Descartes, there are the dualists. To the dualists, mental states, the mind, and the soul are separate from the material body and brain. Dualism, according to Gazzaniga, set back science two thousand years: Aristotle, while he believed in a soul, also believed that the soul dies with the body. According to Descartes, the soul was immortal and immaterial, and being an “essence,” was not subject to scientific scrutiny.
Then, there is a third theory called mentalism. Mentalists such as Roger Sperry and Michael Gazzaniga himself believe that “emergent mental powers must logically exert downward causal control over electrophysiological events in brain activity.” In other words, mental states, the “I,” and consciousness can impact and alter the physical brain. In the 1970s, the mentalist camp was a small minority. Most scientists were materialists.
The New Paradigm
In The Consciousness Instinct, Gazzaniga offers a new paradigm to break free from the old debate between materialists, dualists, and mentalists. His new paradigm of consciousness is based on the latest breakthroughs in understanding how the brain works and also his observations of how people with broken brains function. According to Gazzaniga:
Today we have at our fingertips a vast amount of rapidly accruing new information, and with a little luck, it affords new perspective on how the brain does its magic. The ideas of Descartes and other past thinkers that the mind is somehow floating atop the brain, and the ideas of the new mechanists that consciousness is a monolithic thing generated by a single mechanism or network, are simply wrong. I will argue that consciousness is not a thing. “Consciousness” is the word we use to describe the subjective feeling of a number of instincts and/or memories playing out in time in an organism. That is why “consciousness” is a proxy word for how a complex living organism operates. And, to understand how complex organisms work, we need to know how brains’ parts are organized to deliver conscious experience as we know it.
Descartes believed that consciousness arose from the pineal gland in the brain. Gazzaniga and other neuroscientists understand otherwise. It’s always easier to see how something works by looking at how broken specimens function, and the brain is no different. By looking at people with broken brains, we now know that the brain is a modular organ, built up from many discrete modules, each with its own function and history in the evolution of the species. When one module, or multiple modules are damaged, consciousness remains. What this tells us is that consciousness does not reside in a specific area of the brain. Consciousness is a phenomenon or epiphenomenon that arises from the feedback between the different modules of the brain. It is a deep-rooted function which is incredibly hard to stamp out, even in the most damaged brains.
Split-brain patients offer the strongest testimony to how consciousness is not tied to a specific neural network:
Disconnecting the two half brains instantly creates a second, also independent conscious system. The right brain now purrs along carefree from the left, with its own capacities, desires, goals, insights, and feelings. One network, split into two, becomes two conscious systems.
They used to–and perhaps they still do–perform split-brain surgery to cure epilepsy. The surgery works, and after the nerves between the two cerebral hemispheres are cut, consciousness is also cloven. Here’s an interesting story Gazzaniga shares of Case W.J. After his split-brain surgery, Gazzaniga had tested him to see the results of the surgery:
More crazy yet, in the early months after surgery, before the two hemispheres get used to sharing a single body, one can observe them in a tug-of-war. For example, there is a simple task in which one must arrange a small set of colored blocks to match a pattern sown on a card. The right hemisphere contains visuomotor specializations that make this task a walk in the park for the left hand. The left hemisphere, on the other hand, is incompetent for such a task. When a patient whose brain has recently been split attempts the task, the left hand immediately solves the puzzle; but when the right hand tries to attempt the task, the left hand starts to mess up the right hand’s work, trying to horn in and complete the task. In one such test, we had to have the patient sit on his bossy left hand to allow the right to attempt the task, which it never could accomplish!
If consciousness does not arise from a specific area of the brain, and the dualists and reductionists are mistaken, then from where does it arise? Gazzaniga’s calls his solution complementarity. It’s sort of an awkward word, but I see how he came up with it: the word is a bold rejection of Descartes’ term duality, or the mind – brain split.
The physicists posit that there are two worlds. There is the world of classical physics. This is Newton’s world. The world of objective observers. Processes are deterministic and predictable. Objects in the classical world can be waves or particles, but not waves and particles simultaneously. There is a spooky force over distance (e.g. gravity), but they got over this centuries ago. Classical physics explains the macro world (larger than an atom) quite well. Then there is the world of quantum mechanics. Einstein, Bohr, Schrödinger, Heisenberg, and others came up with this model to explain the subatomic world. This is the world where there are no objective observers. Observers, by observing, alter the system. Processes are probabilistic and unpredictable. Reality is spooky as objects in the quantum world exist as a blur, as both particles and waves simultaneously. It is only the law of large numbers that levels out the blur so that material objects appear concrete. Complementarity describes how subatomic objects exist as both particles and waves simultaneously.
The observer plays a crucial role in the quantum world. By observing quantum processes, the observer collapses the complementary reality of the subatomic object into either a wave or a particle. Choose one experiment, light acts like a particle. But choose another experiment, light acts as a wave. Physicists refer to the inescapable separation of a subject (the measurer) from the object (the measured) die Schnitt. It seemed that human consciousness played a role in collapsing quantum wave functions.
But was human consciousness required in breaking down quantum wave functions. Theoretical biologist came up with an amazing breakthrough when he argued that lower levels of consciousness was able to do this. How low?
Pattee proposes that the gap resulted from a process equivalent to quantum measurement that began with self-replication at the origin of life with the cell as the simplest agent. The epistemic cut, the subject/object cut, the mind/matter cut, all are rooted to that original cut at the origin of life. The gap between subjective feeling and objective neural firings didn’t come about with the appearance of brains, it was already there when the first cell started living. Two complementary modes of behavior, two levels of description are inherent in life itself, were present at the origin of life, have been conserved by evolution, and continue to be necessary for differentiating subjective experience from the even itself.
What Pattee claims is that quantum measurements do not require the physicist-observer. Quantum measurements can take place even on a cellular level. For example, enzymes such as DNA polymerases perform quantum measurement during cell replication.
DNA, Materialism, Symbols, and Life
Materialists say that DNA, being made of chains of atoms, must obey the laws of nature. But, according to Pattee, the materialists don’t see that DNA is also a symbol: it contains the description of the organism. And while DNA contains the description of the organism, it is not the organism in itself. To turn DNA into the organism, two separate steps are required: translation and construction. RNA and other proteins and enzymes “read” the DNA to translate DNA and construct the organism. If the physicist-observer is the highest level of consciousness, the simplest level of consciousness, according to Gazzaniga and Pattee, is the RNA reading the DNA. Like how the physicist-observer observes subatomic particles, so too, the RNA observes the DNA sequence. At the very beginning of life, there was observation. And this observation was carried up to higher and higher levels of consciousness by evolution so that, to continue the analogy, the DNA is likened to the physical brain and the RNA likened to the subjective experience of “I.” This is an exceedingly bold claim.
From Whence Consciousness?
So, “consciousness” began with the beginning of life from when RNA and other bondmaker molecules “gazed” onto the DNA template or blueprint. This gaze between RNA and DNA eventually became human consciousness. But where does our consciousness arise? Gazzaniga uses a soda water analogy to illustrate consciousness. Each module of the brain produces conceptual bubbles that rise to the surface. The “I” is what lies at the surface, and whatever bubble happens to have surfaced constitutes the “I.”
The History of Ideas
For those of you interested in the history of ideas, there’s a story on thermodynamics that Gazzaniga relates that reminds me of a question the astrophysicists are tackling today:
Still, even though Newton’s view of things took some getting used to, his laws seemed to describe most observations of the physical world well, and they became entrenched over the next two hundred years. But soon there was a new challenge to Newtonian physics that had to do with a new invention: the steam engine. The first commercial one was patented by Thomas Savery, a military engineer, in 1698 to pump water out of flooded coal mines. Even as the engines’ design improved, one problem continued to plague them: the amount of work they produced was minuscule compared to the amount of wood that had to be burned to produce it.
The early engines were all super inefficient because way too much energy was dissipated or lost. In the wholly determined world that Newton envisioned, this didn’t make much sense, so the theoretical physicists were forced to confront the puzzle of the seemingly lost energy. Soon a new field of study emerged, thermodynamics, and with it a change in theory about the nature of the world.
Does the story of the missing energy remind anyone of the astrophysicists’ search for dark matter? For galaxies to spin and move through galactic superclusters, they would have to contain much, much more matter than that which we can see. It’s been argued that up to 85% of the mass of the universe has not been discovered. Just as the physicists created thermodynamics to explore and find where all the missing energy in engines was going, perhaps we’re on the verge of a new branch of physics that will discover new laws and properties of matter heretofore unknown. What I’m saying is that the history of ideas seems to recur.
The Chicago School
I had known about the Chicago School of economics. I didn’t know there was a Chicago school of biology as well. Gazzaniga relates how the Chicago School of biology is, at bottom, anti-reductionist:
As Rosen, his [Rashevsky, one of the founders of the Chicago School] student describes, “He had asked himself the basic question: “What is life?” and approached it from a viewpoint tacitly as reductionistic as any of today’s molecular biologists. The trouble was that, by dealing with individual functions of organisms, and capturing these aspects in separate models and formalisms, he had somehow lost the organisms themselves and could not get them back.” He came to the realization that “no collection of separate descriptions (i.e. models) of organisms, however comprehensive, could be pasted together to capture the organism itself…Some new principle was needed if this purpose was to be accomplished.” Rashevsky dubbed that pursuit of the new principle relational biology.
Gazzaniga talks about how patients who have undergone split-brain surgery develop two separate consciousnesses. Presumably, if you tied back the nerves between the two hemispheres of split-brain patients, consciousness would merge back into one. Now, what if you were to wire together separate brains. On the split-brain analogy, if you wired together multiple brains, they should form into one consciousness (you could do experiments wiring left and right hemispheres in series or parallel as well). Would brains wired in series or parallel access to more computing horsepower or a higher consciousness? And, if yes, would this brain cluster still be human? Or, what if you hooked up an Intel processor to the brain. You’d think from reading the news they’re getting close to being able to do this. Yes, this would also be an interesting thought experiment for the ethical philosophers.
Gazzaniga also talks about how evolution added more and advanced modules to the brain. It would have been interesting to read his speculations on where evolution is going to take us next. In another two or three hundred thousand years, will we have acquired additional “modules?” And what will these modules give us? Easier access to abstract mathematics? Higher IQ? Nirvana? Or?
And finally, if, as Gazzaniga postulates, the act of RNA and other bondmaker molecules “gazing on” or “interpreting” DNA constitutes the first act of life and consciousness, then another question arises. Was life accidental, or will Nature bring life into being whenever it can? Is consciousness part of the natural order of things? Does consciousness arise as a natural phenomenon like how gravity will coalesce matter together into stars, clusters, and the spiral arms of the Milky Way galaxy?
Until next time I’m Edwin Wong, and I’m doing Melpomene’s work.