Nathan Gardels is the editor-in-chief of Noema Magazine.
As a non-scientist, and surely naïve lay person, I have always been intrigued by the thought that two apparently opposite theories of consciousness might be plumbing aspects of the same reality.
Erwin Schrödinger, the pioneering quantum physicist, postulated that consciousness is a fundamental feature — the fabric — of the universe, parceled out through the individuated experience of awareness. Gerald Edelman, a Nobel neurobiologist considered the most prominent “materialist” in the field, believed consciousness is entirely a function of embodiment.
“The total number of minds in the universe is one,” Schrödinger wrote in his essay “Mind and Matter.” “In fact, consciousness is a singularity phasing within all beings … consciousness cannot be accounted for in physical terms. For consciousness is absolutely fundamental.”
How is it, he asked, that all human diversity in all times can share the same experience? That a person in one century can see a mountain in the same way as someone in another century? In the fertile mind of the physicist, the unity of consciousness was confirmed by “the empirical fact that consciousness is never experienced in the plural, only in the singular. Not only has none of us ever experienced more than one consciousness, but there is also no trace of circumstantial evidence of this ever happening anywhere in the world.”
On the occasion of the publication of his book “Wider Than the Sky: The Phenomenal Gift of Consciousness” in 2004, I went down to see Edelman at his “scientific monastery” in La Jolla, California. It is worth reproducing a portion of that conversation because of the clarity with which Edelman explained his main theory of “reentrant interactions,” which create the distinct “qualia,” or subjective experiences of human sentience, that, all together, constitute consciousness.
What accounts for consciousness in human beings — that is, to be aware and able to go beyond “the information given” in a particular situation? When did it emerge?
Gerald Edelman: The most important thing to understand is that the brain is “context-bound.” It is not a logical system like a computer that processes only programmed information; it does not produce preordained outcomes like a clock. Rather, it is a selectional system that, through pattern recognition, puts things together in always novel ways. It is this selectional repertoire in the brain that makes each individual unique, that accounts for the ability to create poetry and music, that accounts for all the differences that arise from the same biological apparatus — the body and the brain. There is no singular mapping to create the mind; there is, rather, an unforetold plurality of possibilities. In a logical system, novelty and unforeseen variation are often considered to be noise. In a selectional system, such diversity actually provides the opportunity for favorable selection.
Here, Darwin and his effort to explain variance within biological populations through natural selection provided the key idea. In considering the brain, we are talking about a population of hundreds of billions of cells that far exceeds the number of stars in the sky. The number of possible connections these cells can make exceeds the number of particles in the universe.
To give a sense of this, consider that the cortex of your brain has 30 billion neurons. It has a million billion connections, at least. If you counted one connection per second, you would not finish counting until 32 million years later.
About 300 million years ago, during the transition from reptiles to birds and mammals, the thalamocortical system began to develop from a few collections of neurons, which then grew vastly in number. The thalamus is located in the center of the brain and is about the size of your thumb. It relays signals from all senses but smell to the cortex of the brain which, through manifold loops and pathways, “speaks back” to the thalamus.
Competition for advantage in the environment enhances the spread and strength of certain synapses, or neural connections, according to the “value” previously decided by evolutionary survival. The amount of variance in this neural circuitry is very large. Certain circuits get selected over others because they fit better with whatever is being presented by the environment. In response to an enormously complex constellation of signals, the system is self-organizing according to Darwin’s population principle. It is the activity of this vast web of networks that entails consciousness by means of what we call “reentrant interactions” that help to organize “reality” into patterns.
The thalamocortical networks were selected during evolution because they provided humans with the ability to make higher-order discriminations and adapt in a superior way to their environment. Such higher-order discriminations confer the ability to imagine the future, to explicitly recall the past and to be conscious of being conscious.
Because each loop reaches closure by completing its circuit through the varying paths from the thalamus to the cortex and back, the brain can “fill in” and provide knowledge beyond that which you immediately hear, see or smell. The resulting discriminations are known in philosophy as qualia. These discriminations account for the intangible awareness of mood, and they define the greenness of green and the warmness of warmth. Together, qualia make up what we call consciousness.
To say that consciousness is self-organizing according to evolutionary principles with no ultimate Programmer is to say there is no division between soul and matter, that the spirit isn’t in some spooky domain but rather is a biological phenomenon. Indeed, you say the main purpose of your book is “to disenthrall those who believe consciousness is metaphysical.”
Edelman: It is silly reductionism, of course, to claim that you and I are just bags of molecules. But I do not believe consciousness arises from spooky forces. The brain is embodied, and the body is embedded in its environment. That trio must operate in an integrated way. You can’t separate the activity and development of the brain from the environment or the body. There is a constant interplay between what is remembered and envisioned — an image — and what is actually happening in the senses. We now know that this interplay is enabled by reentrant interactions between the thalamus and cortex.
First, signals enter my brain through this so-called dynamic core. Later, I can “see” images with my eyes closed. But I’m using the same circuits, only in a broader, more general and unique way — perhaps stimulated by a pleasurable memory or an ambitious idea. The brain can speak to itself and the conscious brain can use its discriminations to plan the future, narrate the past and develop a social self. Is consciousness the same as spirit? If you want to call the uniqueness of each individual consciousness a soul, that is all right with me. But there is a problem none of us likes to face. When the body goes, we go.
At the risk of sounding a bit woo-woo, as any speculation about the “hard problem” of the unknowns of consciousness does, can’t both be true? In other words, is it possible that Schrödinger’s “total mind” is a kind of quantum reserve downloaded and differentially phased into qualia through the materialist medium of natural selection, which Edelman calls “neural Darwinism”? Is it the embodied human sensory organs interacting with their environment in feedback loops that unveils the unformed wave of fundamental consciousness through the particle of particular experience?
The correct answer is: Who knows?
“Who Knows?” would be an apt title for the best inventory to date of the myriad views on consciousness, from the metaphysical to the materialist, compiled by Robert Lawrence Kuhn and titled “A landscape of consciousness: toward a taxonomy of explanations and implications,” recently published in the journal “Progress in Biophysics and Molecular Biology.”
Kuhn, who has a Phd in neurobiology, is host of the long-running PBS series “Closer To Truth.” As he writes in the introduction to his journal article, “My purpose here must be humble: collect and categorize, not assess and adjudicate. Seek insights, not answers.” One would be hard pressed to find a more complete guide to exploring all the divergent takes on consciousness than this.
In the coming year, Noema and the Berggruen Institute will set out to explore the divergence of theories Kuhn documents. Who knows what we will find? Stay tuned.
