Catching the Light of the World: The Entwined History of Vision and Consciousness
By Maria Popova
“For this we go out dark nights, searching for the dimmest stars, for signs of unseen things,” the uncommon-minded astronomer and poet Rebecca Elson wrote in her sublime ode to darkness and light. But even down here on Earth, our search for light unfolds amid unseen things — radiant realities beyond the creaturely limits of our vision. Our eyes, those crowning curios of evolution, evolved under our yellow star and now our vision peaks at the yellow portion of the spectrum, on which all visible light is but a slender band wedged between ultraviolet and infrared, spilling into the infinite invisibilia of X-rays and radar, radio and cosmic rays. Our vision is thus both a triumph and a trial of consciousness — something Adrienne Rich captured hauntingly in her poem “Planetarium”:
What we see, we see
and seeing is changing
the light that shrivels a mountain
and leaves a man alive
This intertwining of physics and poetry, impression and interpretation in the very act of seeing comes alive on the pages of the 1993 gem of a book Catching the Light: The Entwined History of Light and Mind (public library) by Arthur Zajonc — a physicist with a poet’s spirit, devoted to “bringing all of who we are to all that the world is.”
He begins with a striking example of the dialogue between eye and mind: Dr. Moreau’s famous case study of a congenitally blind eight-year-old boy whose eyes were restored to optically working condition by a revolutionary surgery at the dawn of the twentieth century, but who found himself unable to actually see the word because his brain had never learned the language of light. Moreau himself wrote:
The operation itself has no more value than that of preparing the eyes to see; education is the most important factor… To give back sight to a congenitally blind person is more the work of an educator than of a surgeon.
The history of medicine is strewn with similar experiences, many ending with the patient so overwhelmed by the psychological crisis of this new language and they outright reject their sighted life and return to the familiar reality without it — a staggering revelation of just how blurry the boundary between physiology and psychology is, just how continually limited we are by the Cartesian inheritance of seeing the body and the mind as separate. Zajonc reflects:
The lights of nature and of mind entwine within the eye and call forth vision. Yet separately, each light is mysterious and dark.
Two lights brighten our world. One is provided by the sun, but another answers to it — the light of the eye. Only through their entwining do we see; lacking either, we are blind.
Light is one of our richest and most versatile metaphors — perhaps because, in the physical world, light is the source of images and without poetic images there would be no metaphors for the mental world — and so this central paradox of vision parallels the central paradox of life. Thoreau captured it two centuries ago as he contemplated knowing versus seeing and what it takes to apprehend reality unblinded by preconception, concluding that “we hear and apprehend only what we already half know.” Zajonc writes:
New impressions threaten the security of a world previously built upon the sensations of touch and hearing. Some decide it is better to be blind in their own world than sighted in an alien one… The sober truth remains that vision requires far more than a functioning physical organ. Without an inner light, without a formative visual imagination, we are blind.
In many ways, we act like Moreau’s child. The cognitive capacities we now possess define our world, give it substance and meaning. The prospect of growth is as much a prospect of loss, and threat to security, as a bounty. One must die in order to become. Newly won capacities place us in a tumult of new psychic phenomena, and we become like Odysseus shipwrecked in a stormy sea. Like him we cling tenaciously to the shattered keel of the ship we originally set out upon, our only and last connection to a familiar reality. Why give it up? Do we have the strength to leave, to change? Perhaps the voices encouraging us to venture out on our own belong only to the cruel Sirens? So we close our eyes, and hold on to what we know.
Besides an outer light and eye, sight requires an “inner light,” one whose luminance complements the familiar outer light and transforms raw sensation into meaningful perception. The light of the mind must flow into and marry with the light of nature to bring forth a world.
But this, Zajonc notes, raises the inevitable question of that outer light — nature’s light, itself invisible yet summoning into view the entire world. It is a question that has been asked, and answered wrongly, with slow increments of error-correction, since the conscious dawn of our species. (Even Plato’s allegory of the cave — the first great thought experiment in understanding consciousness itself as a lens on reality — is woven of light.)
Tracing a panoply of answers across cultures and civilizations — from Euclid (who, blinded by his geometric obsession, believed the eye emitted rays that shine onto the outside world to reveal its contents) to the Arab mathematician and astronomer Ḥasan Ibn al-Haytham in the tenth century (who leapt humanity forward from a spiritual conception of vision to something closer to a mathematical or physical theory) to Kepler in the seventeenth century (who built on Newton’s Optiks to devise a complete geometrical explanation of the camera obscura and an inverse-square law for the intensity of light while landing his mother in a witchcraft trial) to twentieth-century laser experiments with quantum optics — Zajonc frames the central inquiry into how our yearning to understand light has illuminated the human mind itself:
Light touches all aspects of our being, revealing a part of itself in each encounter.
How have we changed this thing called light through the lights of our own consciousness? In the mingling of nature and mind arises an understanding of the life of light.
As a young man, Zajonc had fallen under the spell of Goethe’s beautiful but wrong theory of color perception, growing enchanted with the intersection of science and philosophy, of sight and mind — an intersection from which contemporary science has increasingly cowered, hiding behind the blinders of its neo-Cartesian materialism, against which only the rare poetic physicist dares raise a voice of nuanced dissent. Two and a half millennia after Plato correctly deduced the psychological aspect of vision despite his almost comically incorrect theories about its physiology, observing that “the mind’s eye begins to see clearly when the outer eyes grow dim,” Zajonc looks back on the history of our reckonings with the nature of light and insists on the necessary twining of world and mind:
The light of imagination will occupy half of our history, because of its significance for both the ancient world and poetry and the present world and science. No matter how brilliant the day, if we lack the formative, artistic power of imagination, we become blind, both figuratively and literally. We need a light within as well as daylight without for vision: poetic or scientific, sublime or common… The mind is subtly and usually unconsciously active in sight, constantly forming and re-forming the world we see. Thus, we participate in sight.
In antiquity, our role in seeing, in granting meaning to the sense world was felt more keenly than today; the inner light was closer to consciousness. Unlike the ancient Greeks, we live habitually in a scientific world view that too often treats our participatory role in cognition as unessential or illusory. Yet to see, to hear, to be human requires, even today, our involvement, our ceaseless participation.
This, to be clear, is not a mystical claim. Several years earlier, the influential theoretical physicist John Archibald Wheeler — who salvaged Einstein’s general relativity from its postwar neglect and popularized the term “black hole” — presented his landmark (and ingeniously titled) It from Bit theory, in which he argued that given the information-based nature of all things physical, “this is a participatory universe [and] observer-participancy gives rise to information.” Months later, the human-warped optics of the Hubble Space Telescope demonstrated this equivalence from the backside, giving us our first glimpse of faraway galactic light from the cosmic horizon of our sight and leaving us gasping at a universe “so brutal and alive it seemed to comprehend us back.”
Once again peering back into the long tunnel of sensemaking that stretches between particle physics and Plato, Zajonc writes:
Ancient understandings of sunlight and the sighted eye… will appear, initially, unfamiliar and even absurd. Yet the strangeness may be largely a reflection of the modern imagination we bring to ancient experiences. At every stage, we will need to reimagine the universe, to participate in it empathetically in order to hear the epic song of light.
What begins as a lively, soul-spiritual experience, be it of light or sight, attenuates, clarifies, and divides into optics and psychology. More than an intersecting historical observation, our changing view of light is symbolic of a major change in consciousness, an important threshold crossed in the history of the mind.
There is a sense in which the history of anything is the history of everything, history being the work of human sensemaking — a model of the world made of story and selective memory, each piece of it a fractal miniature of the model-maker’s mind. Inside the history of light — as inside any history — is the history of thought, of the mind reflecting upon itself, the ouroboros of consciousness. The history of science in particular — the place where we build our most elaborate and daring models to be tested continually against the reality they seek to represent — is one extended cautionary parable about the human mind’s perennial tendency to be seduced by its own models, mistaking them for reality, mistaking the extent of our knowledge for the limits of the knowable. Whitman captured this in his searing poem “When I Heard the Learn’d Astronomer” as watched the thrill of discovery tumble into the hubris of certainty in the golden age of telescopic astronomy.
Every epoch has its seductive young science. In our time, we are living through the puerile overconfidence of neuroscience — a discipline no farther along its vector of maturation than astronomy was in Whitman’s time — and its dogmatic view of the brain as the exhaustive engine of experience. Invoking the many persuasive but wrong theories of light and vision over the millennia, each held as dogma in its epoch, Zajonc considers the broader bearing on the history and future of science:
Scientific models certainly have their rightful place. But when does a model become an idol, that is, when is it taken for something other than a model, becoming “reality”? The model of an atom as a miniature planetary system is helpful only as long as it is not taken literally. Quantum physicists discovered long ago the dangers of idolatry. Neurophysiologists have yet to learn the lesson. For many of them, the brain has become an idol; it has become quintessential man.
The dangers associated with this kind of adulation of the brain are innumerable. The image we have of ourselves is a powerful thing; it shapes our actions, and so also the world we fashion for us and for our children. It is important, therefore, patiently and carefully to distinguish between idol and fact… To embrace the results of science without falling into such idolatry… is the challenge we confront in our times. Our success or failure in fashioning a nonidolatrous science will determine much of our future.
In the particular context of understanding the nature of light and vision, this would require shedding our culturally constructed blinders to regard reality on its own terms, which will always exceed our ability to grasp them fully, because we ourselves exist by those terms, are terms. On the other end of the century in which Max Planck, having originated quantum field theory and won the Nobel Prize for it and hurled humanity into the imagination-trying bewilderment of wave-particle duality, cautioned that “science cannot solve the ultimate mystery of nature [because] we ourselves are part of nature and therefore part of the mystery that we are trying to solve,” Zajonc writes:
As the light of the eye dims, that of the world brightens. As the beacon of the eye gradually retreats, the power of sunlight projects itself deeper and deeper into the human being until finally the ethereal emanations of Plato… vanish from the Western scientific sense of self… Our habits of thought become perceptions, and while powerful and pervasive, these are not universal or “true.”
Cognition entails two actions: the world presents itself, but we must “re-present” it. We bring ourselves, with all our faculties and limitations, to the world’s presentation in order to give form, figure, and meaning to that content. The beautiful and productive images we craft on the basis of experience are images only — fruits of the imagination. They are no less true for being so.
In the remainder of Catching the Light, Zajonc goes on to explore various aspects of the twin histories of light and mind, from anatomy to the aurora borealis, from photography to quantum field theory, from Homer to the Brothers Grimm. Complement it with his magnificent On Being conversation with Krista Tippett, then savor Elson’s “Let There Always Be Light (Searching for Dark Matter),” read by Patti Smith and animated by Ohara Hale for the second installment in the animated season of The Universe in Verse in collaboration with On Being:
Published May 28, 2022