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“The Eye altering alters all,” William Blake wrote not long before Darwin extolled the eye as the crown jewel of evolution — an organ of “such wonderful structure” and “inimitable perfection” that it magnetizes us to the mystery of life itself. In On the Origin of Species, he began a section titled “Organs of Extreme Perfection and Complication” with a love letter to the eye:
To suppose that the eye, with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection, seems, I freely confess, absurd in the highest possible degree. Yet reason tells me, that if numerous gradations from a perfect and complex eye to one very imperfect and simple, each grade being useful to its possessor, can be shown to exist; if further, the eye does vary ever so slightly, and the variations be inherited, which is certainly the case; and if any variation or modification in the organ be ever useful to an animal under changing conditions of life, then the difficulty of believing that a perfect and complex eye could be formed by natural selection, though insuperable by our imagination, can hardly be considered real. How a nerve comes to be sensitive to light, hardly concerns us more than how life itself first originated.
But marvelous as our own human eyes may be, they are far from the crowning curio of the animal kingdom. The honor might belong to a creature much lower on the evolutionary ladder of sentience. (“Never say higher or lower,” Darwin exhorted himself in the margins of a book. “Say more complicated.”)
The bay scallop (Argopecten irradians), older than Homo sapiens by some 200 million years, sees with 200 eyes the color of Uranus — bright blueberries bejeweling the ridges of its rippled shell, each equipped with not one but two retinae, containing threefold as many opsins — the light-sensitive proteins in photoreceptor cells, tasked with converting light into electrochemical signals — as ours.
An upper retina covers the scallop’s central field of view, allowing it to see silhouettes moving in the dark. A lower retina is tasked with the animal’s peripheral vision, helping it navigate — unlike other bivalves that live appended to the seafloor, rocks, or vegetation, scallops are fully mobile, moving by a kind of jet-propulsion, clapping their shells together with their powerful adductor muscles as they push water from one end of the shell to the other, swimming in a zig-zag motion.
But the most wondrous aspect of the scallop eye is its structure, more akin to that of a space telescope than to that of the human eye. Images are not projected through a lens that focuses light but reflected onto the retina by a tiny mosaic of mirrors in the back of each eye, tiled with millions of miniature crystals of a shape never seen elsewhere in nature: a flat square.
Although he lived long before powerful microscopes illuminated the wonder of the scallop eye, Darwin was awed by its uncommon beauty visible to the naked human eye — three scallop shells grace the coat of arms of the Darwin family.
Radiating from this alien marvel of nature is a shimmering reminder that there are as many ways of seeing as there are ways of being, and this dazzling difference is precisely what makes our planet a world.
Complement with the science and splendor of seashells and the evolutionary marvel of tetrachromatic vision, then revisit Georgia O’Keeffe on the art of seeing.
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In 1831, at the age of 22, Charles Darwin learned to keep notebooks by emulating Captain Robert FitzRoy of the HMS Beagle.
From Annie Murphy Paul’s The Extended Mind:
Darwin had never kept a journal before coming aboard the Beagle, for example, but he began to do so under the influence of FitzRoy, whose naval training had taught him to keep a precise record of every happening aboard the ship and every detail of its oceangoing environment. Each day, Darwin and FitzRoy ate lunch together; following the meal, FitzRoy settled down to writing, bringing both the formal ship’s log and his personal journal up to date. Darwin followed suit, keeping current his own set of papers: his field notebooks, in which he recorded his immediate observations, often in the form of drawings and sketches; his scientific journal, which combined observations from his field notebooks with more integrative and theoretical musings; and his personal diary. Even when Darwin disembarked from the ship for a time, traveling by land through South America, he endeavored to maintain the nautical custom of noting down every incident, every striking sight he encountered.
As I understand it, Darwin would take a pencil and a notebook off the ship, and then when he was back on board, he would use pen and ink. (He also switched in between notebooks a lot.)
He wrote, “Let the collector’s motto be, ‘Trust nothing to the memory;’ for the memory becomes a fickle guardian when one interesting object is succeeded by another still more interesting.”
And:
[A naturalist] ought to acquire the habit of writing very copious notes, not all for publication, but as a guide for himself. He ought to remember Bacon’s aphorism, that Reading maketh a full man, conference a ready man, and writing an exact man; and no follower of science has greater need of taking precautions to attain accuracy; for the imagination is apt to run riot when dealing with masses of vast dimensions and with time during almost infinity.
I’m reminded that another great journalizer, Henry David Thoreau, started keeping his journal at the age of 20, in 1837, because an older man, Ralph Waldo Emerson, asked him whether he kept a journal.
And I’m also thinking about what the relationship of journaling is to pirates and farmers. A captain’s log is kept to keep track of where you’ve been in space and what happened over time. Thoreau’s log is a record of where he’d been in (mostly) the same place and the changes and what happened there over time…
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