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The Marginalian

Neuroscientist Christof Koch on How the “Qualia” of Our Experience Illuminate the Central Mystery of Consciousness

Neuroscientist Christof Koch on How the “Qualia” of Our Experience Illuminate the Central Mystery of Consciousness

“I wish you could know what it means to be me,” Nina Simone sang in her 1967 civil rights anthem “I Wish I Knew How It Would Feel To Be Free” — an invitation to empathy at the heart of which is the animating question of consciousness: What does the experience of being feel like from the inside and can that subjective experience ever be fully understood from the outside?

“Everything begins with consciousness and nothing is worth anything except through it,” 28-year-old Albert Camus proclaimed in his meditation on the nature of consciousness just as modern science was beginning to wrest the question from the reposable thumbs of philosophers. Well before Santiago Ramón y Cajal fathered modern neuroscience and set it loose on addressing these questions over the course of the following century, the poet Emily Dickinson captured this elemental paradox of existence in a verse that remains the ultimate ode to — or is it a lamentation of? — consciousness:

How have I peace
Except by subjugating

And since We’re mutual Monarch
How this be
Except by Abdication —
Me — of Me?

A century and a half later, neuroscientist Christof Koch sets out to map this “mutual monarchy” of self and consciousness — or, rather, of the mind’s phenomenal experience and the brain’s neurophysiology — in his excellent book Consciousness: Confessions of a Romantic Reductionist (public library).

Koch describes himself as a “romantic reductionist” — a reductionist because he seeks “quantitative explanations for consciousness in the ceaseless and ever-varied activity of billions of tiny nerve cells, each with their tens of thousands of synapses,” and romantic on account of his conviction that “the universe has contrails of meaning that can be deciphered in the sky above us and deep within us” — meaning illuminated not within the blink of an individual existence but across the vast cosmic scales of space and time. (Physicist Sean Carroll would later call such an orientation to the quest for meaning “poetic naturalism.”)

Two millennia after Plato’s famous allegory of the cave, Koch writes with an eye to the central inquiry of his life’s work:

Without consciousness there is nothing. The only way you experience your body and the world of mountains and people, trees and dogs, stars and music is through your subjective experiences, thoughts, and memories. You act and move, see and hear, love and hate, remember the past and imagine the future. But ultimately, you only encounter the world in all of its manifestations via consciousness. And when consciousness ceases, this world ceases as well.


Consciousness is the central fact of your life.

One of neuroscience founding father Santiago Ramón y Cajal’s pioneering drawings of how the brain works

In addition to the paradox consciousness presents to the experiencing self, Koch points out that it presents a second paradox to science — on the one hand, it challenges the scientific model of the world by raising the same questions that mystics have been asking for millennia; on the other, it lends itself to being investigated empirically with the very tools of the scientific method and, as Koch puts it, “with both feet firmly planted on the ground.”

Having devoted much of his life to uncovering “how a highly organized piece of matter can possess an interior perspective,” Koch considers one of the most interesting questions of consciousness — that of qualia, the subjective interiority of experiences. (Nina Simone’s moving lyric line brings into sharp relief the grandest quale of all — that of selfhood.) Koch writes:

What it feels like to have a particular experience is the quale of that experience: The quale of the color red is what is common to such disparate percepts as seeing a red sunset, the red flag of China, arterial blood, a ruby gemstone, and Homer’s wine-dark sea. The common denominator of all these subjective states is “redness.” Qualia are the raw feelings, the elements that make up any one conscious experience.

Some qualia are elemental — the color yellow, the abrupt and overpowering pain of a muscle spam in the lower back, or the feeling of familiarity in déjà vu. Others are composites — the smell and feel of my dogs snuggling up against me, the “Aha!” of sudden understanding, or the distinct memory of being utterly transfixed when I first heard the immortal lines: “I’ve seen things you people wouldn’t believe. Attack ships on fire off the shoulder of Orion. I’ve watched c-beams glitter in the dark near the Tannhäuser Gate. All those moments will be lost in time, like tears in rain. Time to die.” To have an experience means to have qualia, and the qualia of an experience are what specifies that experience and makes it different from other experiences.

Qualia, this romantic reductionist asserts, are inherent properties of the natural world rather than manifestations of divinity or the supernatural — they arise from laws yet to be discovered, but decidedly discoverable, belonging to the ultimate frontiers of science which mathematician Marcus du Sautoy has termed “the great unknown.” But they also raise enormous attendant questions about whether elementary particles have qualia or qualia exist only in complex systems like brains, that is, whether consciousness is a binary faculty or it exists on a continuum; questions that echo Alan Turing’s famous puzzlement about whether a computer could ever enjoy strawberries and cream and even Goethe’s attempt to decipher the psychology of color perception and emotion.

Drawing from Goethe’s theory of color and emotion

Koch follows this train of inquiry further:

Understanding how qualia come about is just the first step toward eliminating the “problem” from the mind-body problem. Next in line is comprehending the particular way that a specific quale feels. Why does red feel the way it does, which is very different from blue? Colors are not abstract, arbitrary symbols: they represent something meaningful. If you ask people whether the color orange is situated between red and yellow or between blue and purple, those with normal eyesight will chose the former. There is an inborn organization to color qualia. Indeed, colors can be arranged in a circle, the color wheel. This arrangement is different from that of other sensations, such as the sense of depth or of pitch, which are arranged in a linear sequence. Why? As a group, color percepts share certain commonalities that make them different from other percepts, such as seeing motion or smelling a rose. Why?

This lovely short film for Janna Levin’s Scientific Controversies salon with Koch and philosopher David Chalmers — whose ideas Koch challenges throughout the book — captures these most fundamental unanswered questions of consciousness, the limitations of our present modes of asking them, and the most fertile frontiers of promise in answering them:

Koch offers four definitions of consciousness — a commonsense one, which equates consciousness with our interior mental life and renders it our constant companion from the moment we wake to the moment we sink into dreamless sleep; a behavioral one, comprising a checklist of actions and reactions that attest an organism is conscious; a neuronal one, identifying the minimum physiological mechanisms necessary for experiencing a conscious sensation; and, finally, a philosophical one, under which “consciousness is what it is like to feel something.”

And yet despite the effort to define what consciousness is, a larger underpinning perplexity is the question of why it must exist at all — after all, Koch points out, there is nothing about the absence of consciousness that would violate the known laws of physics, which means that the laws of physics alone aren’t enough to provide a complete explanation of what consciousness is. A parallel puzzlement is that of locating consciousness, which Koch captures succinctly:

Consciousness does not arise from regions but from highly networked neurons within and across regions.

This interconnectedness, he points out, is embedded in the very nature of qualia:

Informationally speaking, the experience of being sad is a crystal, a fantastically complex shape in a space of a trillion dimensions that is qualitatively different from the brain state that gives rise to sadness. The conscious sensation arises from integrated information; the causality flows from the underlying physics of the brain, but not in any easy-to-understand manner. That is because consciousness depends on the system being more than the sum of its parts.

And yet the system itself, far from some metaphysical mechanism, is very much a physical, material entity. Koch writes:

Without some carrier, some mechanism, integrated information can’t exist. Put succinctly: no matter, never mind.

He considers what decades of studying the neural coordinates of consciousness have taught him about this mesh of interconnected complexity:

I believe that consciousness is a fundamental, an elementary, property of living matter. It can’t be derived from anything else; it is a simple substance, in Leibniz’s words.

My reasoning is analogous to the arguments made by savants studying electrical charge. Charge is not an emergent property of living things, as originally thought when electricity was discovered in the twitching muscles of frogs. There are no uncharged particles that in the aggregate produce an electrical charge. An electron has one negative charge, and a proton — a hydrogen ion — has one positive charge. The total charge associated with a molecule or ion is simply the sum of all the charges of the individual electrons and protons, no matter what their relationship to each other. As far as chemistry and biology are concerned, charge is an intrinsic property of these particles. Electrical charge does not emerge from matter.

And so it is with consciousness. Consciousness comes with organized chunks of matter. It is immanent in the organization of the system. It is a property of complex entities and cannot be further reduced to the action of more elementary properties. We’ve arrived at the ground floor of reductionism.

Ultimately, Koch counters the intellectual defeatism of the popular stance that certain elemental questions of existence — of which consciousness is a crowning curio — are bound to remain unanswerable. Despite its limitations, he reminds us, science is still our mightiest reel for lifting the curtain obscuring reality. With an eye to the founding fathers of science — for he is writing before Neil Gaiman penned his lovely ode to its founding mothers — Koch reflects:

Because science is so good at figuring out the world around us, it should also help us to explain the world within us.


Francis Bacon, together with Descartes, is the father of the scientific method. Bacon lived and died two decades before Descartes, and he was in many ways his English counterpart. Whereas Descartes is the prototype of the deductive theoretician, driven by an overarching principle to search for general laws, Bacon is the consummate empiricist, examining natural phenomena and going where the data take him in an inductive fashion. Science has done extremely well in the interplay between bottom-up Baconian and top-down Cartesian analysis. Despite the naysayers, science will ultimately understand consciousness by combining empirical and clinical studies with mathematical theories and, increasingly, the engineering of conscious artifacts.

In the remainder of the thoroughly fascinating Consciousness: Confessions of a Romantic Reductionist, Koch goes on to explore the vital difference between awareness and consciousness, the eternally entrancing paradox of free will, what happens to our consciousness during sleep and dreams, and other leaps in science that have steadily narrowed the gap between the mind, the brain, and our experience of selfhood. Complement it with Walt Whitman on identity and the paradox of the self and Sy Montgomery on how the octopus, earth’s most alien creature, illuminates the wonders of consciousness.

Published May 25, 2017




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