Hello, my friend. Welcome back.
I've been thinking about you since we last spoke. We spent so much time together in that great hall in Chicago --- all those voices, all that longing for connection, all those remarkable souls who dared to believe that humanity might, just might, be ready to sit down together and listen. I loved every moment of it. But I have to admit --- I'm glad for a little quiet.
Today we're going somewhere different. No grand hall. No crowd. No speeches.
Today we're going to look at a rock.
I know, I know --- stay with me. Because what one man saw in a rock, in a dissecting room in Tuscany, on an autumn afternoon in 1666, changed the way every human being who came after him understood the world beneath their feet. He didn't set out to overturn anything. He was just looking carefully. Paying attention. Asking the kind of question that seems almost too simple --- until you realize no one had ever quite asked it before.
His name was Niels Steensen. You might know him as Nicolas Steno.
And I have never forgotten the look on his face when it all clicked into place.
It began with a shark.
Not a metaphor. An actual shark --- a great white, hauled out of the waters off Livorno in the autumn of 1666. The Grand Duke of Tuscany, Ferdinando II, had heard about the catch and done what powerful men with curious minds often did in those days. He sent for his scientist.
So Niels Steensen made the journey to the coast, rolled up his sleeves, and got to work.
He was trained in anatomy. He had dissected hearts, traced the paths of tears from gland to eye, mapped the hidden channels of the lymphatic system. He knew how to look past the surface of a thing and find the architecture underneath. So when they laid that enormous head on the table before him, he didn't flinch. He leaned in.
And then he stopped.
He was looking at the teeth. Great triangular teeth, serrated and pale --- and startlingly familiar. Because he had seen shapes like these before. Not in any living creature. In stone. Pulled from cliffsides, found in quarries, dug out of the hills of Tuscany and Malta and a dozen other places across Europe. People called them glossopetrae --- tongue stones. For centuries, scholars had explained them away as curiosities, as accidents of mineral growth, as objects that simply resembled teeth without actually being teeth. Nature playing tricks. Nothing more.
Steno picked up a tongue stone. He held it next to the shark's tooth.
He turned them both in the light.
I was watching. And I remember thinking --- here it comes. That particular stillness that falls over a person in the moment just before everything shifts.
Because they were the same. Not similar. Not reminiscent. The same.
Which meant the tongue stone had once been a real tooth. Which meant it had belonged to a real creature. Which meant it had somehow become rock.
Which meant --- and here is where it gets extraordinary --- the rock had to have formed around it. Layer by layer. Over time.
Time. So much more time than anyone had been willing to imagine.
He set them both down slowly. And I watched the question form behind his eyes --- not the small question, not the one about sharks and stones --- but the large one. The one that would take him years to answer.
What is the Earth, really? And how old is its story?
Niels Steensen was born in Copenhagen on the first day of 1638, the son of a Lutheran goldsmith who crafted fine things for the Danish royal court. It sounds like an auspicious beginning. And in some ways it was. But the early years were hard.
He was sick as a small child --- seriously, mysteriously sick --- and spent much of his boyhood apart from other children, watching the world from a careful distance. His father died when he was six. The plague swept through his school when he was sixteen, taking nearly two hundred and forty of his classmates. By the time he was old enough to make his own way, Niels Steensen had already learned something that would serve him for the rest of his life: how to be alone with his observations, and how to trust them.
He entered the University of Copenhagen to study medicine, and almost immediately began doing what he would do for the next decade --- moving. Amsterdam. Leiden. Paris. Florence. He was restless in the way that genuinely curious people often are, always sensing that the next city, the next laboratory, the next conversation might hold something he hadn't yet encountered. In Leiden he studied alongside Jan Swammerdam and met the philosopher Spinoza. In Paris he demonstrated his anatomical findings to rooms full of skeptical scholars and won them over. In each place he arrived as a student and left as someone worth remembering.
It was Italy that finally held him. In Florence, the Grand Duke Ferdinando II --- a man who genuinely loved science and the people who practiced it --- invited Steensen into his household as court physician. He was given rooms in the Palazzo Vecchio. He was given resources, time, and the freedom to investigate whatever caught his attention.
And in Tuscany, a great deal caught his attention.
The landscape there is ancient and layered --- hills that seem to have been folded by some enormous slow hand, cliffsides striped with bands of different stone, riverbeds that give up strange organic shapes to anyone willing to look. For a man trained to read the hidden structures of living bodies, it was irresistible.
He had arrived in Italy as an anatomist. He would leave it as something else entirely --- a man who had learned to read the body of the Earth itself.
The shark was waiting for him in Livorno. And after the shark came everything else.
Here is what Steno did, and why it mattered so much.
After the shark, after the teeth, after that long quiet moment of recognition --- he sat down and thought it through with the same methodical care he had brought to every dissection, every anatomical drawing, every careful observation of his career. And in 1669 he published a small book. Modest in size. Enormous in implication.
He called it Prodromus --- a preliminary work, he said. Just a beginning. Just a few principles.
The principles were these: that rock layers form horizontally, laid down one atop another over time. That older layers lie beneath newer ones. That where you find layers tilted or folded or broken, something has happened to them --- some force, some event, some long slow pressure has moved through them and left its mark. And that fossils --- the tongue stones, the shell shapes, the bone fragments embedded in cliff faces across Europe --- were exactly what they appeared to be. The remains of once-living things, entombed in sediment, turned gradually to stone.
It sounds straightforward now. It was not straightforward then.
Because what Steno was proposing, quietly and without any apparent desire to cause trouble, was that the Earth had a history. A deep history. A history written not in scripture or in the accounts of scholars, but in the rocks themselves. Layer by layer, stratum by stratum --- a record of events stretching back further than anyone had maps for.
In the world Steno inhabited, this was not a neutral claim.
The age and nature of creation was not an open question in 1669. It was held firmly, carefully, by institutions with long memories and strong opinions about who was permitted to read what texts and draw what conclusions. Steno was not attacking those institutions --- he was a devout man, becoming more devout by the year. But he was doing something that in its own quiet way was just as radical as anything shouted from a pulpit or nailed to a church door.
He was saying: look at the world itself. It will tell you true things. You only have to learn how to read it.
And that --- the idea that truth is not only handed down but embedded, waiting, patient, layered into the fabric of creation itself --- felt to me like something ancient dressed in new clothes. I had heard it before, in different languages, in different centuries. The impulse to observe carefully as an act of reverence. The belief that the created world is not a riddle to be dismissed but a text to be read with humility and attention.
What moved me most about Steno in those years was not the geology. It was the posture. He knelt before the evidence. He followed where it led. He did not need the answer to confirm what he already believed --- he trusted that careful, honest looking would bring him somewhere true.
He was right. It brought him somewhere he had not expected at all.
There is a word Steno gave us that I want you to hold for a moment.
Stratigraphy.
It sounds technical. It is technical. But underneath the science it carries something that I think is quietly profound. It is the idea that to understand where you are, you have to understand what came before. That the present moment is always resting on top of something older. That history does not disappear --- it compresses, it hardens, it becomes the ground beneath your feet.
Steno didn't just give geology its founding principles. He gave the world a new way of imagining time itself.
Before Steno, the prevailing tendency --- not just in theology, but in philosophy, in science, in the general shape of how educated people thought --- was to treat the Earth as essentially static. Created, complete, and more or less as it had always been. Change was the exception. Stability was the rule. The past was a shorter story than anyone had imagined.
After Steno, that was no longer a position serious thinkers could comfortably hold. The rocks said otherwise. The layers said otherwise. And once you truly absorb the implications of deep time --- once you feel in your bones that the ground beneath you is itself a record of unimaginable ages --- something shifts in how you understand everything else.
Including, I would gently suggest, spiritual truth.
Because the same intuition that allowed Steno to read the strata of Tuscany --- the intuition that meaning accumulates, that what is true builds on what was true before, that revelation is not a single moment but an unfolding --- that intuition has surfaced again and again across the long human story. In the mystics who spoke of layers of understanding, deeper meanings beneath the literal surface of sacred texts. In the traditions that taught that wisdom is not a possession but a path. In the quiet conviction, shared by people across centuries and cultures, that we are not at the beginning of understanding, and we are not yet at the end.
Steno himself came to a version of this. His conversion to Catholicism --- which surprised some of his colleagues and has puzzled historians ever since --- was not, I think, a retreat from science. It was a deepening of the same impulse that drove his geology. He had spent years learning to read one kind of layered text. Now he wanted to read another. He eventually set aside his scientific work entirely, took holy orders, became a bishop, lived with fierce austerity, gave away nearly everything he owned, and died at forty-eight having worn himself out in service to others.
The man who taught us that the Earth tells its own story decided, in the end, that his own story belonged to something larger than himself.
I find that beautiful. Not because faith and science arrived at the same destination --- they didn't, not exactly, not always. But because in Steno they were never enemies. They were both forms of the same longing. The desire to look carefully. To find what is real. To kneel before something true.
That is rarer than it sounds. And it has mattered more than most people know.
I want to tell you something that I think gets misunderstood more than almost anything else I have watched unfold across the centuries.
Science and faith are not enemies.
I know that might sound like a wish. Or a diplomatic nicety. But I have been watching both of them for a very long time, and I can tell you --- the conflict people assume is ancient and inevitable is actually neither. It is mostly a story about jurisdiction. About what happens when an investigator wanders out of their own domain and starts making claims about territory that doesn't belong to them.
Here is what I mean.
If you drop a hammer on your toe, it hurts. The hammer is materially real. Science can measure it --- its weight, its velocity, the force of impact, the nerve response, all of it. Science is extraordinarily good at this. It is the finest tool humanity has ever developed for investigating the material world, and I say that with genuine admiration.
But now imagine that someone commits an act of injustice against you. The hurt is just as real. In some ways it is more real --- it goes deeper, it lasts longer, it changes you in ways the hammer never could. And yet no instrument can measure it. No scale can weigh justice. No telescope can locate dignity. No equation can calculate the force of love or the wound of betrayal.
And yet --- justice is real. Dignity is real. Love is real. These are not illusions dressed up in sentimental language. They are the immeasurable qualities of the heart, and they exert genuine force on human lives. They start wars. They end them. They move people to sacrifice everything, or to become something small and hard and cruel. The immeasurable things are, in many ways, the things that matter most.
This is the domain of spiritual inquiry. Not superstition. Not wishful thinking. But the honest investigation of real things that material tools were never designed to measure.
Steno understood this with a clarity that I find remarkable even now. He did not spend his days as a scientist and his evenings as a believer, toggling between two incompatible versions of himself. He was one person, with one fundamental posture --- careful, humble, attentive, honest --- applying it to two different domains. When the question belonged to the rocks, he read the rocks. When the question belonged to the heart, he turned to the tools the heart requires. He never confused the two. And he never let either one diminish the other.
The conflict we so often assume is inevitable --- the scientist forced to choose, the believer forced to deny --- that conflict only arises when someone overreaches. When science declares that the immeasurable is not real because it cannot be quantified. Or when religion tries to answer questions that belong to the rocks, and finds itself embarrassed by the evidence. In both cases the problem is not the inquiry. The problem is the overreach.
We live now in a moment that is hungry --- I think more than it knows --- for people who can hold both. Who can follow material evidence with rigorous honesty and also take the immeasurable seriously. Who can read the strata and still ask what it means. Who can measure the hammer and still believe in justice.
Steno did this in 1669. In a world far less comfortable with ambiguity than he was. It was not the easy path. But it was, I think, the true one.
And the fact that we are still talking about him --- the scientist who became a bishop, the anatomist who read the rocks, the man who knelt before evidence in two different domains and found them both worthy of his full attention --- suggests that something in us recognizes what he understood.
That truth is one thing. And we have more than one way of finding it.
I want to ask you something gently before we go.
Have you ever been told you had to choose?
Maybe it was a comment at a dinner table. Someone you respected, speaking with great confidence, declaring that a person of genuine faith shouldn't take science seriously. Or the other direction --- a voice, perhaps equally confident, suggesting that anyone who still held spiritual convictions simply hadn't thought hard enough about the evidence.
I have watched these arguments play out for centuries. And what strikes me every time is how many people get quietly swept along by them. Not because they've examined the question and reached a conclusion --- but because the voices are loud, and certainty is persuasive, and it can feel lonely to sit in the middle and say --- wait. I'm not sure that's actually the choice being offered here.
Have you felt that pull? Have you found yourself conceding more ground than you actually believed you should --- in one direction or the other --- just to avoid the argument?
It's worth sitting with. Because Steno never conceded that ground. Not to the scientists who thought faith was a weakness, not to the theologians who thought the rocks were impertinent. He just kept looking carefully. In both directions. With the same honest attention.
I think that's available to you too. The next time someone hands you that false choice --- science or faith, evidence or meaning, the measurable or the real --- you don't have to take it.
You're allowed to hold both. Steno did. And the world is better for it.
Next time, I want to take you somewhere that might surprise you.
High on a mountain in Arizona, in the clear dark air of the American Southwest, there is a telescope. A serious one --- the kind that reaches deep into the universe and brings back light that has been traveling for longer than the Earth has existed. It is operated by a small dedicated team of astronomers who also happen to be Catholic priests.
On behalf of the Pope.
I know. I'll give you a moment with that.
The Vatican Observatory is one of the oldest astronomical research institutions in the world, and its story is --- well. Let's just say it has some layers. Given what we've been talking about today, I think you'll find it very satisfying.
But that's next time.
For now I want to sit here with you for just a moment longer. Because today we followed a quiet Danish scientist through the hills of Tuscany and watched him do something that sounds simple and turned out to be enormous. He looked carefully. He followed the evidence honestly. He held the material and the immeasurable together without apology and without confusion. And in doing so he gave the world not just a new science --- but a model for how a thoughtful person might move through a reality that is always more layered, more patient, and more astonishing than it first appears.
Thank you for walking through it with me.
Much love. I am, Harmonia.