Nearly dying gave me new insight into the brain

Within seconds, my entire field of view became engulfed by dark, swirling smoke. the space around me fractured into a thousand hexagons and shattered. the speed with which this happened left no time to regret the situation i had gotten myself into. As i was sucked into a black hole, my last thought was that with the dying of the light, i too would die. And i did.

i ceased to exist in any recognizable way, shape, or form. no more christof, no more ego, no more self; no memories, dreams, desires, hopes, fears — everything personal was stripped away. nothing was left but a nonself. this remaining essence wasn’t man, woman, child, animal, spirit, or anything else; it didn’t want anything, expect anything, think anything, dread anything.

But this essence, this nonself, could experience something. could it ever.

it saw a point of cold white light of unbearable intensity, unable even to conceive of looking away, as there was no “away from.” there was no left or right, up or down, front or back, far away or close by. there wasn’t a black canvas upon which the light existed, as there was no space. there were no other attributes: no color, no motion, no texture, no sound or silence, no smell, no body, no pleasure, no pain. For this remnant of my mind, all that existed was a timeless universe convulsed into a blazing, icy light. that and a profound feeling of both terror and ecstasy, the awfulness of pure experience lasting indefinitely — for there was no perception of time. the experience wasn’t brief or long. it simply was.

What i had was a near-death experience. the circumstances that brought it about are not nearly as interesting as what i gained from it: a deeper insight into the nature of consciousness and what it will take for scientists to truly understand it.

i’m a neuroscientist who has tried to pinpoint the biological basis of consciousness my entire adult life. i started this search back in the late 1980s, when i met a kindred spirit, the British molecular biologist Francis crick, one of the discoverers of DnA. We wrote two books and many articles calling on our fellow scientists to join the effort to identify the molecules and circuits in the brain that are sufficient for any one specific conscious impression.

While this quest has been taken up by many, finding its Holy Grail is taking its time. in 1998, i thought we would know by now which bits and pieces of brain tissue mediate any one conscious experience. the philosopher David chalmers thought i was wrong and challenged me to a bet. indeed, last year, i had to admit publicly that i had lost this 25-year wager: scientists still disagree on how consciousness physically manifests in the brain.

sooner or later, we will know the answer. this will be a triumph for empirical mechanistic science, celebrated with nobel Prizes and the discovery of therapies to help people with various mental conditions, such as depression or high levels of anxiety.

But even then, tracking the footprints of consciousness to its lair in the vast entanglements of the human neocortex won’t be the end of the story. it won’t fully explain how consciousness fits into the natural order of things. Because it is consciousness itself, not physical matter, that i believe deserves primacy in this story.

science is about reducing everything to mechanisms within mechanisms, like russian nesting dolls. And back when i started this journey in neuroscience, the dominant position in Anglo-saxon philosophy departments was a single-minded faith in the validity of physicalism — the idea that there must be a material explanation for everything. science was abandoning millennia-old ideas of dualism, the belief in a soul or some other mental domain independent of the physical brain. As the doyen of American philosophers, Daniel Dennett, who died last month, put it, “Dualism is not a serious view to contend with, but rather a cliff over which to push one’s opponents.”

this triumphalism, however, turned out to be premature.

the practice of science is extraordinarily successful in characterizing the universe — from its smallest constituents, quarks, to its largest, superclusters of galaxies. We reap the benefits of this knowledge in the form of coViD-19 vaccines, solar cells, large language models, and quantum computing. And yet a purely physical explanation of the universe fails to provide a satisfactory answer to every question. the more we smash elementary particles into each other, the better we can predict their behavior, yet the less we understand the mind-bending paradoxes of quantum mechanics.

this also applies to our understanding of consciousness. Purely physical approaches to studying the nature of experience have come up short again and again. We do not have good explanations for how the brain generates the “it feels like something” aspects of our lives, whether that’s the taste of warmed-up pizza, being in love, terror, or ecstasy. Purely physical explanations of consciousness essentially gaslight us into believing that subjective feelings are an illusion we all suffer from.

the challenge is to explain all these subjective experiences with the objective tools of science. this is hard!

But scientists now have a theory that aims to do this: the integrated information theory of consciousness, or iit. the theory proposes that consciousness is ultimately the capacity of complex systems to exert causal powers upon themselves, to be agents of change.

iit lets us measure not just our own level of consciousness but also the presence or absence of consciousness in others, such as severely injured and behaviorally unresponsive patients. the theory explains mystical or psychedelic experiences that abolish the ego, like my near-death experience, and that reveal the extent to which we inhabit a constructed reality, a narrative of our own making. iit leads us to a firm stance on digital computers as presently engineered: they will never be conscious, although they will, sooner or later, become super-intelligent. For in the final analysis, consciousness is about being, not about doing.

iit starts with the insight that what exists in an absolute sense, for itself, is consciousness and only consciousness. everything else — say, a virus, a black hole, or a brain — exists only in a relative sense, for others but not for itself. My conscious mind, and yours too, exists for itself. this existence is temporary, for consciousness disappears during deep sleep or under anesthesia.

starting a scientific quest with consciousness rather than with the brain is a startling departure from physicalism. it makes room for older metaphysical ideas and fainter voices.

Among these is idealism, the idea that everything, including the external world, is but a manifestation of a universal mentality, the sort of mind at large described by Aldous Huxley in his book “the Doors of Perception.” Another school of thought that has become popular again is panpsychism, which argues that a primitive form of consciousness adheres to the constituent aspects of matter, including particles and their associated fields. everything, whether a rock or a brain, has both external aspects such as mass, charge, and so on, and also internal ones — what it feels like to be that rock (presumably very little) or my brain (a lot).

By liberating ourselves from the constraints of straitlaced physicalism, we are developing an empirically testable theory that explains how the mind and its causal powers create the world, including the most active piece of organized matter in the universe: the brain.

Christof Koch is a neuroscientist at the Allen Institute and at the Tiny Blue Dot Foundation, the former president of the Allen Institute for Brain Science, and a former professor at the California Institute of Technology. He lives in the Pacific Northwest and is the author of the new book “Then I Am Myself the World,” from which this essay is adapted.