In the autumn of 1664, when the black plague shrouded the world in a deadly pandemic and universities sent their students home for a quarantine the end of which no one could foresee, a young man besotted with mathematics, motion, and light returned to his illiterate mother's orchard, where he watched an apple fall. A revolution of understanding rose in its shadow — he fathomed the mechanics of a mystery that had enchanted humanity for epochs: how bodies can act on other bodies, attracting one another impalpably and invisibly across space and separation, as if by magic.
Religions had called it grace. Science, with the young Newton at its helm, called it gravity.
We have since discovered three other presently irreducible fundamental forces winding the clockwork of reality, with gravity the weakest of the four, 1038 times weaker than the strongest, and yet the most immediate, the most embodied, the most readily graspable by our creaturely intuitions. The unfathomed thing once explained as magic is now a commonplace of common sense, woven into our elemental understanding of the world and, in consequence, woven into our metaphors — those handles on the door of understanding.
Art from Sun and Moon — a collection of Indian celestial myths illustrated by tribal artists.
It is on gravity's metaphor we lean when we speak of the binding force of love — the attraction that draws ensouled bodies to one another, as if by magic. But for all the progress science has made in the epochs since Newton, along the long procession of history in which the brilliant and the brokenhearted have walked hand in hand, this binding force is still a mystery, still something closer to grace, perhaps the only form of grace that is real.
This might always remain so — as the stardust-residue of ideas that was once Carl Sagan reminds us, "the universe will always be much richer than our ability to understand it." A vast part of me hopes it does remain so — some things are more important felt than known: felt fully and unconditionally, for they can only ever be understood incompletely and conjecturally. Rachel Carson, for all her devotion to the poetics of reality we call science, knew this when she insisted that it is not half so important to know as to feel. E.E. Cummings knew it when, in his impassioned case for the courage to be yourself, he observed that "whenever you think or you believe or you know, you're a lot of other people: but the moment you feel, you're nobody-but-yourself… the hardest battle which any human being can fight."
Centuries after Newton and generations after Carson and Cummings, Jane Hirshfield — another philosopher-poet intimately attuned to the poetics of reality, an ordained Zen Buddhist who thinks deeply and writes splendidly about the living realities and lush metaphors of the natural world — addressed this in a poem that has saved me, and continues to save me, across many seasons of being. Originally published in her 1988 lifeline of a collection Of Gravity & Angels (public library) — a title evocative of the posthumous record of Simone Weil's exquisite consciousness, Gravity and Grace — it is generously read here for us by the poet herself:
FOR WHAT BINDS US
by Jane Hirshfield
There are names for what binds us:
strong forces, weak forces.
Look around, you can see them:
the skin that forms in a half-empty cup,
nails rusting into the places they join,
joints dovetailed on their own weight.
The way things stay so solidly
wherever they've been set down —
and gravity, scientists say, is weak.
And see how the flesh grows back
across a wound, with a great vehemence,
more strong
than the simple, untested surface before.
There's a name for it on horses,
when it comes back darker and raised: proud flesh,
as all flesh,
is proud of its wounds, wears them
as honors given out after battle,
small triumphs pinned to the chest —
And when two people have loved each other
see how it is like a
scar between their bodies,
stronger, darker, and proud;
how the black cord makes of them a single fabric
that nothing can tear or mend.
Complement with David Whyte's sensitive meditation on what we place between ourselves and true love and Derek Walcott's "Love After Love" — a classic hymn to living ourselves back to life after heartbreak — then revisit Jane Hirshfield's timeless ode to resilience, "The Weighing."
"Your children are not your children. They are the sons and daughters of Life's longing for itself," Kahlil Gibran wrote in his poignant verse on parenting. And yet we are, each of us, someone's child — physiologically or psychologically or both — and they sing themselves through us as we sing ourselves into our longing for life, whether we like the melody or not.
Like a Zen koan, this fact becomes utterly discomposing when you begin thinking deeply about the fundamental, layered realities beneath the mundane, even banal factuality of the fact. Parents — the very notion of them. The notion that you — this immensely complex totality of sinew and selfhood, this portable universe shimmering with a million ideas and passions and little ways of being-in-the-world that make you you — began as a glimmer in someone else's eye, a set of chemical reactions that became molecules that became cells in someone else's body before they constellated into you. The notion that so many dimensions of your personhood, so many of the givens you take for granted in making sense of the world, were forged by someone other than yourself (and possibly other than the body that begot the cells that became you) — someone who occupies, in the cosmogony of you, this strange and staggering position of arbiter between the existence and nonexistence of the particular you that you are.
Kinship by Maria Popova. (Available as a print.)
The doubly discomposing experience of what happens when that arbiter crosses the threshold of their own nonexistence is what Mary Gaitskill addresses in her thoughtful, tender contribution to Take My Advice: Letters to the Next Generation from People Who Know a Thing or Two (public library) — the wondrous 2002 anthology by artist and writer James L. Harmon, inspired by one of his own spiritual parents: Rilke and his timeless Letters to a Young Poet.
Gaitskill writes:
My advice here is very specific and practicable. It is advice I wish someone had given me as forcefully as I'm about to give it now: When your parents are dying, you should go be with them. You should spend as much time as you can. This may seem obvious; you would be surprised how difficult it can be. It is less difficult if you have a good relationship with the parent or, even if you don't, if you're old enough to have lost friends and to have seriously considered your own death. Even so, it may be more difficult than you think.
With the sensitive caveat that there exist people "to whom this general directive does not apply" and her advice is not meant as a rebuke to those people, Gaitskill addresses those of us raised by fallible parents who, in one way or another, failed dreadfully at the deepest task of parenting — unconditional love:
If you're a young person who has had a bad relationship with your parent, it's a nightmare of anger, confusion, and guilt. Even if you hate them, you may still not want to believe it's happening… Even if your parents have been abusive, physically or emotionally, they are part of you in a way that goes beyond personality or even character. Maybe "beyond" isn't the right word. They are part of you in a way that runs beneath the daily self. They have passed an essence to you. This essence may not be recognizable; your parents may have made its raw matter into something so different than what you have made of it that it seems you are nothing alike. That they have given you this essence may be no virtue of theirs — they may not even have chosen to do so. (It may not be biological either; all I say here I would say about adoptive as well as birth parents.)
Art by Ekua Holmes from The Stuff of Stars by Marion Dane Bauer.
Being with a dying parent, Gaitskill notes, is a way of honoring the fact — so basic yet so incomprehensible a fact — that they will soon be gone, and with them will go your experience of being their child in the way you have known, a fundamental way in which you have known yourself. At the heart of this dual recognition is "the hard truth that we know nothing about who we are or what our lives mean." She writes:
Nothing makes this plainer than being in the presence of a dying person for any length of time. Death makes human beings seem like very small containers that are packed so densely we can only be aware of a fraction of what's inside us from moment to moment. Being in the presence of death can break you open, disgorging feelings that are deeper and more powerful than anything you thought you knew. If you have had a loving, clear relationship with your parent, this experience probably won't be quite as wrenching. There may in fact be moments of pure tenderness, even exaltation. But you might still have to watch your parent appear to break, mentally and physically, disintegrating into something you can no longer recognize. In some ways this is terrible — many people find it absolutely so. There is another side to it, though: In witnessing this seeming breakage, we are glimpsing the part of our parents that doesn't translate in human terms, that which we know nothing about, and which the human container is too small to give shape to.
Art by Dorothy Lathrop, 1922. (Available as a print.)
Because any emotional experience we have when facing another is always an emotional experience we have within, and about, ourselves — especially if that other gave rise to this self — facing this supraknowable quality is facing the limits of our own self-knowledge. Gaitskill writes:
Knowing your feelings is hard too because there's so much emotion, it's hard to tell which is truest. Part of you might want to leave right away; part of you might want to stay forever. That's why I advised that you stay "for as long as you can." What that means will vary with each person, with the needs of the parent and the other relations. A day might be enough, or it might take a whole month. If it's a prolonged situation, it might be good to leave for a few days and come back. Those decisions are so personal they are beyond the scope of my advice — except my advice to pay close attention to yourself. If you feel, To hell with this, I'm getting out, don't worry — there's room for that. Maybe in fact you should leave. But before you do, be sure that voice is not shouting down a truer one. When your parents die, you will never see them again. You might think you understand that, but until it happens, you don't.
Art by Margaret C. Cook from a rare 1913 English edition of Walt Whitman's Leaves of Grass. (Available as a print.)
In a sentiment on the surface contradictory but in fact consonant with the deeper meaning of what artist Louise Bourgeois inscribed into her lifelong diary in her old age — "You are born alone. You die alone. The value of the space in between is trust and love." — Gaitskill concludes:
They say that you come into the world alone and that you leave alone too. But you aren't born alone; your mother is with you, maybe your father too. Their presence may have been loving, it may have been demented, it may have been both. But they were with you. When they are dying, remember that. And go be with them.
Complement this fragment of Take My Advice — which also includes novelist Richard Powers on the most important attitude you can take toward your life and philosopher Martha Nussbaum on how to honor your inner world — with Richard Dawkins on the luckiness of death, Marcus Aurelius on embracing mortality as the key to living fully, and Zen Hospice Project founder Frank Ostaseski on the five life-redeeming invitation to extend in facing death, then revisit this tender illustrated meditation on the cycle of life.
"Everything that is possible is real," Bach scribbled in the margins of his music three centuries ago, when the existence of other galaxies was unimaginable and hummingbirds were considered magic, when the fact of the atom was yet to trouble the young Emily Dickinson and the fact that it is mutable was yet to splinter the foundation of reality as we understood it.
"What will they think of my music on the star of Urania?" the young Beethoven wondered in his marginalia upon hearing of the discovery of Uranus, daring to imagine the unimaginable. In two centuries, his Fifth Symphony would sail past the seventh planet on a golden disc aboard a spacecraft launched into the unknown on the wings of laws discovered by a college student watching an apple fall on his illiterate mother's orchard during a plague quarantine and a sickly brokenhearted mathematician defending his mother in a witchcraft trial.
The great gift of science is that it continually reveals to us what is real, unpeeling the wallpaper of our knowledge to reveal newer and newer layers of nature, deeper and deeper substrata of reality. The great peril of science — this eternal impulse of human nature — is that the human mind continually limits what is possible, erecting walls of assumption between itself and the reality of nature. And yet the entire fact of life — your individual life, and mine, and life itself as a feature of the universe — is a matter of probable impossibilities.
Plate from An Original Theory or New Hypothesis of the Universe by Thomas Wright, 1750. (Available as a print, as a face mask, and as stationery cards.)
This interplay, and how to liberate our search for truth from our craving for certainty, is what Italian physicist Chiara Marletto explores in The Science of Can and Can't: A Physicist's Journey through the Land of Counterfactuals (public library) — part field guide to her particular realm of study, part manifesto for the countercultural courage to keep unmasoning the walls of the imaginable and bending the mind beyond the accepted horizons of the possible. What emerges is an impassioned, scrumptiously reasoned insistence that all breakthroughs in science require "as much imagination and perceptiveness as you need to write a good story or a profound poem."
Counterfactuals — explanations about what could or could not be caused to happen in the physical universe, as distinct from the standard scientific theories about what is bound to happen based on what has happened in the past — are one such thrilling mode of rotating in the palm of the mind the unsolved mysteries of nature in order to examine them from revelatory new perspectives, perspectives blind-spotted by our present assumptions. Counterfactuals are the science of otherwise — the physics counterpart to Jane Kenyon's excellent poem — shimmering with new ways of understanding everything from information to time to free will.
Double rainbow from Les phénomènes de la physique, 1868. Available as a print and face mask.
In the foreword, Marletto's collaborator David Deutsch observes that the rate of scientific discovery over the past few centuries has been increasing exponentially, but the discovery of new fundamental truths about nature has stalled and an indolence about attempting new modes of explanation has set in. He writes:
There has never been a time when there have been more blatant contradictions, gaps, and unresolved vagueness in our deepest understanding of nature, or more exciting prospects to explore them. Sometimes this will require us to adopt radically different modes of explanation.
Illustrating the validity of counterfactuals as a mode of understanding, he gives the example of a computer, which could record and process nothing new if every change to the contents of its memory were pre-set in the factory — a computer "can hold information only if its state could have been otherwise."
Marletto places at the heart of her case for counterfactuals the notion of resilience — not resilience in the creaturely sense, to which we aspire and which trees so perfectly embody, but a deeper kind of resilience, existing on the fundamental level of information yet giving rise to all the physical reality that makes the creaturely kind possible — resilience as the dazzling, rare feature of our universe, even within the no-design fundamental laws of which a system can continue existing in an ever-changing environment. With an eye to genes — those recipes for keeping a species in existence, peppered with mutation — she writes:
What distinguishes helpful changes in the recipe from unhelpful ones? It is a particular kind of information: information that is capable of keeping itself instantiated in physical systems. It is resilient information.
[…]
"Knowledge" merely denotes a particular kind of information, which has the capacity to perpetuate itself and stay embodied in physical systems — in this case by encoding some facts about the environment… Knowledge is the key to resilience… In fact, knowledge is the most resilient stuff that can exist in our universe.
Art by Deborah Marcero from The Boy Whose Head Was Filled with Stars: A Life of Edwin Hubble by Isabelle Marinov.
Leaning on Karl Popper's famous pillar of sensemaking — "Knowledge consists in the search for truth… It is not the search for certainty." — she adds:
There are no absolute sources of certain truth: any good solution to a problem may also contain some errors. This principle is based on fallibilism, a pillar of Popper's explanation of rational thinking. Fallibilism makes progress feasible because it allows for further criticism to occur in the future, even when at present we seem to be content with whatever solution we have found. It leaves space for creating ever-improving theories, stories, works of art, and music; it also tells us that errors are extremely interesting things to look for. Whenever we try to make progress, we should hope to find more of them, as fast as possible.
She turns to the two ways in which nature and human nature generate new knowledge, the generative process we call creativity — "by conjecture and criticism, in the mind; by variation and natural selection, in the wild" — and considers the crucial difference between the two:
Natural selection, unlike conjecture and criticism, cannot perform jumps: each of the recipes that leads to a new resilient recipe must itself be resilient — i.e., it must code for a successful variant of a trait of the particular animal in question that permits the animal's survival for long enough to allow replication of that recipe, via reproduction. But there may be viable, resilient recipes coding for useful traits that can never be realised because they would require a sequence of nonresilient recipes to be realised first, which is impossible, as those recipes produce animals that cannot survive and cannot pass on their genes.
The thinking process, in contrast, can perform jumps… The sequence of ideas leading to a good idea need not consist entirely of good, viable ideas. Nonetheless, knowledge creation in the mind, too, can enter stagnation and stop progressing. We must be wary of not entering such states both as individuals and as societies. Particularly detrimental to knowledge creation are the immutable limitations imposed by dogmas, as they restrain the ability to conjecture and criticise.
Woven into Marletto's case for counterfactuals is her love letter to science and the art of explanation:
Physics is a dazzling firework display; it is profound, beautiful, and illuminating; a source of never-ending delight. Physics is about solving problems in our understanding of reality by formulating explanations that fill gaps in our previous understanding. The point of physics is not the particular calculation about the fall of an apple. It is the explanation behind it, which unifies all motions—that of the apple with that of a planet in the solar system, and beyond. The dazzling stuff consists of explanations: for they surprise us by revealing things that were previously unknown and very distant from our intuition, with the aim of solving a particular problem.
[…]
The appearance of the dark sky at night… can be explained in terms of unexpected underlying phenomena involving things like photons, the remarkable fact that the universe is expanding, and so on. None of those elements is apparent in the sky itself, but they are all part of the explanation for why it looks as it does, in terms of what is really out there. Explanations are accounts of what is seen in terms of mostly unseen elements.
"Spectra of various light sources, solar, stellar, metallic, gaseous, electric" from Les phénomènes de la physique by Amédée Guillemin, 1882. (Available as a print and as a face mask.)
"What we see, we see / and seeing is changing," Adrienne Rich wrote in her ode to astrophysics. It is changing, however, only when we change the way we look, change our tools for looking, be they physical instruments — the microscope and the telescope, revealing unseen layers of reality — or the instrument of the mind, which devises the microscope and the telescope and the theory. I hear Thoreau bellowing his admonition down the hallway of time as he puzzled over what it takes to see reality unblinded by our preconceptions: "We hear and apprehend only what we already half know." Marletto writes:
The traditional conception of physics cannot possibly capture counterfactual properties, because it insists on expressing everything in terms of predictions about what happens in the universe given the initial conditions and the laws of motion only — in terms of trajectories of apples or electrons, forgetting the other levels of explanation. But these other levels of explanation are essential sometimes to grasp the whole of physical reality.
Drawing on the example of Neptune and the neutrino — both discovered not by direct observation of the previously unseen planet or particle but by observing curious contradictions in the surrounding system and deducing from them that something in the set of assumptions about what the system is and how it works must be revised. She writes:
As always happens with contradictions, something in the assumptions has to give.
[…]
Declaring something impossible leads to more things being possible.
In one of the book's many charming touches defying the segregation of science from its sensemaking twin — art — she gives an exquisite example of counterfactuals at work in one of humanity's most abiding masterworks of storytelling and sensemaking: the Ancient Greek myth of Theseus (which also inspired the greatest thought experiment about the nature of the self and what makes you you).
Theseus and the Minotaur by Alice and Martin Provensen from their lovely 1956 illustrations for the Iliad and the Odyssey.
Marletto writes:
Theseus, son of Aegeus, king of Athens, went to Crete to kill the Minotaur. Theseus made an agreement with his aged father that if he defeated the Minotaur, on their return his crew would raise white sails on the ship; if he perished, they would raise black sails. So off went Theseus, and he defeated the Minotaur. But on his way back, distracted by all sorts of things (including, possibly, the presence of his fiancée, Ariadne, on the ship!), he forgot to tell the crew about the sails. The crew left the black sails on, and Aegeus, who from the highest tower of Athens could see the ship approaching, thought his son was dead. So he threw himself into the sea and drowned. This tragic story is why the sea is now called the Aegean.
Now suppose we asked our master storyteller to tell that story with the constraint that he can formulate statements only about what happens — that is, he must report the full story without ever referring to counterfactual properties. In particular, he cannot refer to properties that have to do with what could or could not be done to physical systems.
This task turns out to be impossible: for the story to make sense, and to convey fully its meaning, two attributes of the ship are essential: one, that it can be used to send a signal, by assuming one of two states — white sail showing or black sail showing; the other, that the state of having black or white sails can be copied onto other physical systems — such as Aegeus's eyes and brain. The copiability property tells us that the flag contains information.
Without these two counterfactual properties, the myth would be robbed of sense and could not possibly produce in the mind of the reader the tragic feeling, the shift in understanding, that gives rise to its millennia-wide moral. The myth of Theseus — a sensical story of tangible things like continents and oceans, a story of profoundly human things like ships and sons — helps grasp the analogous counterfactuals at work in more abstract things. A bit — that unit of information powering our digital universe — may seem like an abstract thing, but it is essentially a Thesian ship's sail: there are the two binary states that can switch from one to the other, there is the ability to be copied. Any system endowed with these two counterfactual properties is an information medium — a conduit of knowledge.
Marletto reflects:
Adopting counterfactuals brings entities that look superficially like immaterial abstractions into the domain of physics. Information and knowledge, for example, have been traditionally considered as mere abstractions — as things that do not belong to the physical world. However, by considering the counterfactual properties of physical systems that enable information and knowledge, one refutes this idea: because whether or not a physical system has those properties is set precisely by the laws of physics.
Art from Thomas Wright's An Original Theory or New Hypothesis of the Universe, 1750. (Available as a print and as a face mask.)
The ultimate promise of counterfactuals as portals to possibility comes most vibrantly abloom in one of the several short genre-bending vignettes Marletto composes to illustrate the scientific concepts — a story-upon-story set in the crucible of materialism, Ancient Greece. She imagines the childhood of the legendary conqueror Alexander the Great — who by his death at thirty-two would have created one of the vastest empires in the history of our species — and his time as an uncommonly broad-minded pupil of Aristotle: a boy asking the vastest unasked questions, hungry to fathom his own mind. In one of their conversations, Alexander wonders what it is in him that endows him with the capacity for wonder — with the ability to savor poetry and philosophy and the abstract art of mathematics — if he is made of the same material as concrete things like rocks and grass. Marletto's Aristotle answers:
What's clear is that the mind has characteristic properties that make it capable of relating to things that are abstract. I suspect that it obeys the same laws as rocks and grass, though we have yet to find these laws and understand how to apply them to the mind.
Complement The Science of Can and Can't with physicist Alan Lightman's poetic meditation on what makes our improbable lives worth living between the bookends of possibility, then revisit the story of Alan Turing, the world's first digital music, and the poetry of the possible.
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