Time, at first, was an instinct. The sun rose, and it was morning. Shadows stretched, and it was late. People lived by rhythms, not numbers. They knew when to plant, when to harvest, when to rest. They marked time by seasons, not seconds.
Soon came calendars—lunar, solar, or both. Rituals were fixed to solstices. Festivals tracked full moons. Sundials carved the day into arcs. Bells rang out canonical hours for prayer. Ships steered by starlight. Still, time remained loose, local, and deeply human.
But as civilisation grew, so did the need for precision. Empires expanded. Trade routes stretched across deserts and oceans. Schedules mattered. Time needed boundaries. Not just a sense of when—but an agreement on how long. And so we began to divide.
The 24‑hour day, which feels natural now, is an ancient construct. It came from the Babylonians, who divided both day and night into twelve equal parts. Why twelve? Because they used a base‑60 number system, and twelve divides into sixty easily. Also, if you count finger bones with your thumb, you’ll find twelve segments on one hand. No astronomy required—just anatomy and arithmetic.
Later, Greek astronomers formalized this into sky‑maps. Hipparchus, in the 2nd century BCE, divided the celestial sphere into 360 degrees—again, a Babylonian inheritance. The idea of cutting time like we cut circles—into degrees, then minutes, then seconds—emerged from this thinking.
In Latin, pars minuta prima was the “first‑small part”—what we now call a minute. Pars minuta secunda was the “second‑small part”—what we now call the second. These were mathematical concepts, not physical observations. No one saw a second in the stars. It was a geometric afterthought. An elegant fiction.
The first mechanical clocks in 13th‑century Europe could chime the hour. Later, the minute. But no one could reliably track a second until the pendulum clock was invented in the 17th century. Even then, seconds were used for celestial calculations, not daily life. It would be centuries before a human being lived by them.
So long before relativity, long before atoms, the second was born from layered approximations—a relic from medieval astronomy, descended from Babylonian number games and Greco‑Roman sky charts.
Not discovered. Invented.
A measure that fit the machinery—not the universe.
As we became more exact with our measurements, we also grew more comfortable declaring time as something absolute—ready to be pinned down universally.
Then came Newton. In Principia Mathematica, published in 1687, Isaac Newton made a quiet but enormous claim: time exists independently of anything that happens in it. He called it absolute time—and he was very clear about what he meant.
Time, he wrote, flows “equably, without relation to anything external.” It moves forward at a steady rate, regardless of clocks, matter, or motion. It is not affected by how we measure it. It simply is.
In a universe governed by Newtonian physics, time is the ultimate background. Space is the stage. Time is the metronome. Events unfold upon that stage in perfect coordination. Everything moves through time like passengers on a train—carried along by an invisible rhythm they cannot change.
This wasn’t a conclusion drawn from experiment. It was an assumption, woven into the mathematics to make it work.
And it did work—beautifully. Newton’s laws let us predict the motion of planets, projectiles, pendulums. Time was the variable that made the equations go. It became the baseline of classical physics—the X‑axis of history.
And once it worked, we stopped questioning whether time itself was real.
What followed was refinement. Clocks grew better. Pendulums were replaced by balance wheels, then by quartz oscillators. Trains demanded synchronized timetables. Telegraphs stitched the world together. Suddenly, time had to be the same in Paris and in London. Time zones were invented. Noon became something agreed upon.
But none of this was built on a deeper understanding of time itself. It was built on our growing ability to keep time the same. Precision was increasing. Understanding was not.
Then, in 1905, Einstein disrupted everything. He showed that Newton’s universal time didn’t exist. Time, it turned out, was relative to motion and to gravity. Two observers could disagree on the duration between events—and both could be right. There was no single, master clock ticking in the background.
Time had cracked. But rather than abandoning it, we made it more precise.
In 1967, the General Conference on Weights and Measures redefined the second—no longer as a fraction of a day, but as 9,192,631,770 oscillations of a cesium‑133 atom. That number wasn’t special. It was chosen to match what earlier clocks already said a second was. This was not discovery. This was retrofit. A phenomenological match. We used a quantum system to agree with what our mechanical clocks had told us time should be.
We didn’t redefine the second based on what time is. We defined it based on what we had already decided it should be.
And then, to make things neater, we fixed the speed of light. Not measured it—fixed it. In 1983, we defined the metre as the distance light travels in 1/299,792,458 of a second. This means that the speed of light is no longer something we discover through experiment. It’s something we declare to be true—by definition.
We made time exact by pegging it to light. And we made light exact by pegging it to time.
It is a perfect circle. Elegant. Useful. Entirely constructed.
But if we’ve pinned time down so neatly, how did Einstein’s revolutionary insight—that time is relative—survive? More than that, what if it’s not even “time” at all?
You are an ace skier. Your twin brother is a champion snowboarder. Together, you stand at the top of a high, steep slope, gazing down into a deep white valley. The air is sharp. The snow is smooth. The race is about to begin—but it isn’t fair. It never was.
Your hearts beat in perfect synchrony—one beat per second. Both of you are fearless. Both of you leap.
Your descent is straight and swift. Gravity takes you in a clean line down the fall of the mountain. Your brother, tied to the geometry of his board, has no such freedom. He must carve. His path zigzags. It’s not slower—but it is longer.
At first, you’re side by side, suspended. Neither of you has touched the snow. One heartbeat. You’ve both dropped ten metres. Another heartbeat—twenty‑five. But soon the difference begins to show. Your line remains tight and vertical. His arcs widen. He dances across the slope, always moving—but never quite downward.
Ten heartbeats later, you are near the bottom. The land begins to level. You coast. Your skis sink gently into the snow. Stillness.
Much later, your brother completes his last turn, glides across the valley floor, and slows beside you.
You’ve spent 100 heartbeats on your descent. He’s spent 1,000.
It feels like time passed differently for each of you. But what actually differs is the length of your path. This is not just a poetic metaphor. This is physics.
The slope you descended is not just a mountain—it is the entropy1 gradient. And your journey through it defines your age—not in seconds, but in distance traveled through entropic space. It feels like time, but it is not time. It is geometry.
Why do you think of heartbeats? Because you’re counting them. Because you’re alive. Because you’re biological. But imagine for a moment that you were not. Imagine that you were rocks—one round and rolling straight, the other elliptical and tumbling in long loops. There would be no heartbeat to count. No breath. No experience. No “time.” Only distance. Only structure. Only form.
Your movement down the slope was not temporal—it was physical. What you call “time passed” was simply the path you took through a shaped field of entropy.
The idea that all things age the same way is a myth born of clocks. Clocks do not measure structure. They count intervals—pendulum swings, crystal oscillations. They do not care what they are made of, or where they are. They assume the substrate doesn’t matter.
Einstein looked at time and described it in terms of motion. He told us: if you move faster than your brother, and expend fewer heartbeats along the way, then you are younger. To Einstein, time had slowed for you. And in a way, he was right.
But here’s the kicker: the mountain does not care.
Einstein described time from the point of view of the observer. He focused on the heartbeat—not the slope. On the intervals—not the descent. He forgot the geometry of the terrain beneath your feet.
His time is subjective. Local. Dependent on frames. But the mountain—the entropy gradient—has no clock. Only curvature.
In the framework upheld by this book, what matters is not how many ticks you count, but how far you fall through entropy. Einstein’s equations still work. They still describe the apparent differences in motion and aging. But what they describe is not “time.” It is path. It is modulated descent.
What feels like slower time is simply less descent. What we call aging is the integral of motion along the entropic slope—a geometric accumulation, not a temporal one.
And unlike time, the slope is not relative. It is structural. It is the same for everyone and everything—your twin, a rock, a neutrino2, or a planet.
Time, in the end, is only real if you insist on measuring it. The slope was always there.
Looking back up the slope, it might seem like you’ve only traveled a thousand metres. But your actual journey was longer because the slope wasn’t uniform. At the top, the gradient was steep, and each moment of descent carried you rapidly forward. Lower down, the gradient flattened, and your progress slowed. Even though you moved as quickly as possible, the total distance you covered—when measured through the changing gradient—was far greater. That distance is your true age. This is why the gradient matters.
But the slope analogy only explains so much. What if we push the idea to its extreme? Let’s be absurd. Let’s be impossible. Let’s be subatomic.
You’ve been given an Ant‑Man suit. You shrink—not just small, but quantum‑small. You see a photon pass, and you hitch a ride.
Iron Man—still human‑sized—watches as you vanish into the distance. A second later, you are 300,000 kilometres away. A year or so later, you’ve reached the Oort Cloud. Several billion years pass. Iron Man, now immortal, sees you slip silently past the edge of the observable universe.
But how much time have you experienced?
None.
You, the photon‑rider, experience nothing. No seconds. No minutes. No aging. No awareness. Because from your “frame”—if you can call it that—all events are simultaneous. The start and the end collapse into one. Distance exists. Trajectory exists. But time? Gone.
Which means this: if you can traverse billions of light‑years in no time at all, then time is not fundamental. It’s just a shadow cast by your scale. A consequence of your inability to move without aging. A trick played by biology.
And if time disappears the moment you try to take it seriously—if the extreme case shows how absurd it really is—then maybe it was never real to begin with. It was just how we measured the slope.
Because every single theory stumbles on time. It must be real—and yet it is relative. It’s the same contradiction as treating light as both a wave and a particle. For over a century, hundreds of thousands of scientists have tried to reconcile the universe of the very small with the universe of the very large using the same conceptual tools. And the only way to do it is through fantastic contortions of credibility and mystery.
It is mainstream thought that every decision spawns a new universe—an infinite number of them.
It is mainstream thought that if you fell into a black hole and survived, you could watch the entire future of the universe unfold in an instant.
It is mainstream thought that everything—every particle, every galaxy—once existed as a single, infinitely dense point.
These are not fringe ideas. They are the best we’ve got.
And to make them work, we invent the unseeable. We model the unknowable. We construct entire realities based on assumptions we’re no longer allowed to question.
Because Einstein—whose genius gave us a theory so elegant, so perfect, that it became an axiom—stopped one step too soon.
Some physicists—especially those at the experimental frontier—still defend free will, not out of sentiment, but out of necessity.
Anton Zeilinger, one of the most accomplished experimental physicists of the past fifty years, has made this clear: without freedom of choice, quantum theory unravels. His experiments with entangled particles, celebrated worldwide, rely on the assumption that the settings of measurement devices are not predetermined—that the physicist, at the moment of measurement, can actually choose.
Why? Because if those settings were entangled with the particle’s properties from the beginning—if everything was already written—there is no quantum magic. No spooky action. No statistical violation. Just a story that’s already over.
Zeilinger’s defense of free will is, at its heart, a defense of a segment of physics that cannot survive without time. Without a meaningful “before” and “after,” you cannot set up an experiment. Without a present moment in which choice occurs, you cannot compare outcomes. You cannot observe a violation of causality if causality was never there.
But that is precisely what the Block Universe implies. And so we face this fork: either insist on some freedom of choice—and keep the puzzle pieces of quantum theory upright—or accept that everything is fixed—and let quantum weirdness vanish.
But what if the quantum weirdness, so strongly defended, is a tautological argument? It is weird because the axiom says time is real; therefore time is real.
No. The weirdness should be an indication that time may not be real. The way to explore that is to see if you can explain away the weirdness, make it disappear, in an explanation that does not rely on time.
(Spoiler alert—you can—we will do it together.)
And if we prove that, free will becomes an artefact of scale, an illusion of perspective. At which point you might say:
“But I can choose to have a cookie or not!”
Yes, you can—right up until you don’t. And once it’s done, it was never any other way.
As I’ve often joked:
“Of course you have free will, my love. You just didn’t.”
It’s a glib line, but it captures the dilemma. Within your lived moment, you feel the freedom of choice. And from that slice, you indeed make a choice. Later, you look back and see that the past was fixed. And tomorrow is simply next week’s past.
This contradiction between your immediate sense of freedom and the entropic reality of the slope is best understood not as an error, but as two vantage points colliding. Free will is perfectly real for you—locally, psychologically—even as the Block Universe stands unmoved.
In a fully deterministic, timeless framework, that “freedom of choice” is just a placeholder for our ignorance. It’s the last stand for a system that still needs time to mean something—even if only locally.
But if time is not real, and if perceived motion is simply descent through a structured field, then there is no moment of choice. There is only structure. Only slope. Only geometry.
Which means this: the freedom we cling to in quantum mechanics is not evidence of quantum weirdness. It’s the residue of a false premise.
And if that premise collapses—if the notion of “choice” is revealed to be an artefact of perspective—then so too does the cloud of uncertainty we’ve been living in.
You are not defending your career. You are not defending your funding or your institution or your pride. Step back. See the mountain.
Because once you accept it—once you accept that time is a block, that free will still exists but is purely subjective, that the future is not unwritten but simply unlived—the universe blossoms into simplicity.
It doesn’t become less strange—but it becomes far more honest.
Many modern physicists now quietly accept the Block Universe, or a close cousin: a super‑deterministic framework. The difference between the two is subtle but important, and we’ll return to it in a later chapter. For now, it’s enough to know that the notion of a fixed past, present, and future—or at least something close to it—is no longer fringe. It is inching toward the mainstream, one determined step at a time.
Because once you remove time from the pedestal, everything else can finally fall into place.
1. It is practically tradition to explain entropy using a teenager’s bedroom. Who am I to break with such a fine trend. Think of entropy as messiness. “Chaos” and “disorder” are technically more accurate, but far less amusing. Everything—especially a teenager’s bedroom—moves from tidiness to messiness. It is inevitable. Physicists are more precise. They speak of thermodynamic entropy: the movement from an energetic state to a state of no energy. That is not the sense in which I’ll use it here. I’m talking about pure, geometric entropy. It will, as you’ll see, become the most relied‑upon term in this book. I use it as a replacement for time. It is not a perfect replacement, and it should not be. Time is irreversible. Entropy is not. You can tidy the bedroom by expending effort. But in doing so, you’ve borrowed that order from somewhere else. You burned calories. You transferred mess. The overall entropy in the house has not reversed—only redistributed. We’ll revisit the term as we need to be more specific. But for now, every time you see the word entropy, substitute: “messiness.”
2. A neutrino is a nearly massless, neutral particle that passes through ordinary matter almost undisturbed. "Sterile" neutrinos are hypothetical versions that do not even interact via the weak nuclear force—the already faint channel used by known neutrinos—making them completely invisible to current detection methods.
Discussion