The Order of Time Notes ⏱️

The mystery of time is ultimately, perhaps, more about ourselves than about the cosmos.

Carlo Rovelli

We don’t know much about time, other than our uniquely human perspective on how it works and what it means.

Carlo’s book is a fascinating examination of what it means to be a being that exists within time.

These notes are my best attempt to put together the main ideas in his book as a lay reader.

I mostly made these notes for my own personal review, so if you are someone that isn’t me and reading this I apologize for how disorganized this is.

Time Dilation 🌎

Time Passes Faster in Mountains > Sea Level

Quick Definition ✅ – Time Dilation is the elapsed time difference between two measurements (clocks) results from relative velocity to each other OR a gravitational difference between two discrete locations.

Sort of like this:

Here is another good breakdown by BigThink:

Scientists first observed this “time dilation” effect on the cosmic scale, such as when a star passes near a black hole. Then, in 2010, researchers observed the same effect on a much smaller scale, using two extremely precise atomic clocks, one placed 33 centimeters higher than the other.

Again, time moved slower for the clock closer to Earth. 🌎

The differences were tiny, but the implications were massive: absolute time does not exist. For each clock in the world, and for each of us, time passes slightly differently. But even if time is passing at ever-fluctuating speeds throughout the universe, time is still passing in some kind of objective sense, right?

Maybe not.

This elastic motion of time stuck with me throughout the entire book. Time is a uniquely subject projection and lacks the absolutism that most think of.

Our experience of time is relatively consistent as the Earth exerts massive gravitational effect on us, effectively grounding us to this time. The Earth essentially wraps space time around us.

Side note – > Maybe this is why time seems to pass so quickly when we are in motion and so slow when we are bored. 🤔

  • The characteristic features of time have proved to be approximations, mistakes determined by our perspective, just like the flatness of the Earth or the revolving of the sun.
  • Einstein understood that time does not pass uniformly everywhere before the development of clocks accurate enough.
  • Time is relative and depends on where you are.
  • But there are not just two times. Times are legion: a different one for every point in space. There is not one single time; there is a vast multitude of them. 🤯

Physics does not describe how things evolve “in time” but how things evolve in their own times, and how “times” evolve relative to each other.*

This is the first consideration of time. There is a strong local bias towards thinking time is objective.

Time has lost its first aspect or layer: its unity. It has a different rhythm in every different place and passes here differently from there.

Entropy of Time 🌊

We mostly think of time flowy linearly from past to present to future. We can’t go into the past or future, we are firmly fixed in the present.

Time flows forward. 👉

This is known as the arrow of time or the Thermodynamic arrow of time.

This one is a bit tricky so let me do my best to explain it.

But first we need to understand symmetry and asymmetry.

What we experience as the one way arrow of time is the one-way direction or asymmetry. Time moves forward and can’t go in both directions..it’s not symmetrical.

The arrow of time is the uniform and unique direction associated with the apparent inevitable “flow of time” into the future.

According to many, there might be a link between what we perceive as the arrow of time and a quantity called entropy.

Commonly known as “a measure of disorder” in a physical system, there are actually two better ways to think about it.

Entropy can be viewed as the number of possible arrangements of the (quantum) state of your system.

If you have more options for how you could arrange your system so that it remains identical, you have higher entropy than if there are fewer options.

Entropy = disorder

It’s also useful to think of entropy as a measure of how much thermal (heat) energy could possibly be turned into useful, mechanical work.

When you have lots of energy available to do work you have a low-entropy system, whereas if you have very little available energy (a near-equilibrium temperature room), you have a high-entropy system.

High entropy would indicate less energy available for useful work in a system. Low entropy would suggest greater energy availability.

Think about it like this:

To recap – High energy = less available work energy. Low entropy = more

Nature is full of examples such as these: what we conventionally call irreversible reactions in physics.

Drop an ice cube into a warm drink, and the ice will melt, resulting in a cool drink; a cool drink will never separate into a warm drink and an ice cube. Create a room with a barrier between two halves of it, one half hot and one half cold, and then open a gate allowing the particles between the two halves to mix.

Over time, the room will equilibrate, and both halves will be filled with intermediate temperature particles. Never, no matter how long you wait, will the two halves spontaneously separate into a room that’s half-hot and half-cold again

Things can’t go backwards….👈

This is the price the Universe extracts over time: the total entropy of a system can never decrease. These interactions are not reversible.

Entropy of a closed (self-contained) system can only increase or stay the same over time; it can never go down.

In other words, over time, the entropy of the entire Universe must increase. It can never and will never decrease back to initial conditions.

It’s the only known law of physics that appears to have a preferred direction for time.

Now that we’ve established what entropy is we can see how our perception of time is asymmetrical meaning it only moves one direct NOT two.

Here is the tricky part…. this only happens at the macro scale. At the micro quantum scale there is a symmetry of time “travel” that can allow things to seemingly backwards in time. 🤯

Keep that thought in your head… we’ll come back to it.

Let’s continue on….

In other words – physical processes at the microscopic level are believed to be either entirely or mostly time-symmetric: if the direction of time were to reverse, the theoretical statements that describe them would remain true.

This is known as T-Symmetry.

You can think of a teeter totter to under how time can oscillate back and forth with perfect symmetry.

Example – > Gravity, for example, is a time-reversible force. A ball that is tossed up, slows to a stop, and falls is a case where recordings would look equally realistic forwards and backwards

Once entropy is added at the macro scale it becomes NON reversible.

The process of the ball bouncing and eventually coming to a stop is not time-reversible. While going forward, kinetic energy is dissipated and entropy is increased. Entropy may be one of the few processes that is not time-reversible.

Our perceived sense of time flowing is the result of a very unbreakable and undeniable second law of thermodynamics.

As a system advances through time, it becomes more statistically disordered. This asymmetry can be used empirically to distinguish between future and past.

Additional Book Notes

  • The difference between past and future, between cause and effect, between memory and hope, between regret and intention . . . in the elementary laws that describe the mechanisms of the world, there is no such difference.
  • The crucial point here is the difference from what happens with falling bodies: a ball may fall, but it can also come back up, by rebounding, for instance. Heat cannot. This is the only basic law of physics that distinguishes the past from the future.
  • The arrow of time appears only where there is heat.* The link between time and heat is therefore fundamental: every time a difference is manifested between the past and the future, heat is involved. In every sequence of events that becomes absurd if projected backward, there is something that is heating up.

Here is a great little exerpt that explains entropy in action at various scales:

We see the water in a glass like the astronauts saw the Earth from the moon: calm, gleaming, blue. From the moon, they could see nothing of the exuberant agitation of life on Earth, its plants and animals, desires and despairs. Only a veined blue ball. Within the reflections in a glass of water, there is an analogous tumultuous life, made up of the activities of myriads of molecules—many more than there are living beings on Earth. This tumult stirs up everything. If one section of the molecules is still, it becomes stirred up by the frenzy of neighboring ones that set them in motion, too: the agitation spreads, the molecules bump into and shove each other. In this way, cold things are heated in contact with hot ones: their molecules become jostled by hot ones and pushed into ferment.

Thermal agitation is like a continual shuffling of a pack of cards: if the cards are in order, the shuffling disorders them. In this way, heat passes from hot to cold, and not vice versa: by shuffling, by the natural disordering of everything.  

The growth of entropy is nothing other than the ubiquitous and familiar natural increase of disorder.

This disorder also has a place in the physical makeup of our brains:

Entropy growth orients time and permits the existence of traces of the past, and these permit the possibility of memories, which hold together our sense of identity. I suspect that what we call the “flowing” of time has to be understood by studying the structure of our brain rather than by studying physics: evolution has shaped our brain into a machine that feeds off memory in order to anticipate the future. This is what we are listening to when we listen to the passing of time. Understanding the “flowing” of time is therefore something that may pertain to neuroscience more than to fundamental physics. Searching for the explanation of the feeling of flow in physics might be a mistake

The difference between past and future does not lie in the elementary laws of motion; it does not reside in the deep grammar of nature. It is the natural disordering that leads to gradually less particular, less special situations.

At this point if you’re still a bit confused, take a look at this beautiful video narraed by Doctor Strange

Time as Blurred Particularity 🌡️

Our entire notion of reality is blurred. We don’t see the entirely of everything going on and totally incapable of seeing anything beyond our local condition.

We can only discern the big events, not the infinitesimally small

The notion of “particularity” is born only at the moment we begin to see the universe in a blurred and approximate way.

If I observe the microscopic state of things, then the difference between past and future vanishes.

Remember I mentioned this before… things ONLY seem consistent due to localism of time and our ability to observe time only in the macro sense of the world. 🤯

In a microscopic description, there can be no sense in which the past is different from the future.

This is the disconcerting conclusion that emerges from Boltzmann’s work: the difference between the past and the future refers only to our own blurred vision of the world.

Is it really possible that a perception so vivid, basic, existential—my perception of the passage of time—depends on the fact that I cannot apprehend the world in all of its minute detail? On a kind of distortion that’s produced by myopia?

All this undermines the very basis of our usual way of understanding time.  

But just as with the movement of the Earth, the evidence is overwhelming: all the phenomena that characterize the flowing of time are reduced to a “particular” state in the world’s past, the “particularity” of which may be attributed to the blurring of our perspective

Another way to think about this is we experience the linearity of time because we are incapable of seeing the entirely of all things.

Sort of like Neo in the Matrix..

I will end with the mind-boggling fact that entropy, as Boltzmann fully understood, is nothing other than the number of microscopic states that our blurred vision of the world fails to distinguish.

Time has lost another of its crucial components: the intrinsic difference between past and future. Boltzmann understood that there is nothing intrinsic about the flowing of time. That it is only the blurred reflection of a mysterious improbability of the universe at a point in the past.              

Einstein had realized that it was slowed down by speed. The consequence of this discovery for our basic intuitive perception of time is the most devastating of all.

For everything that moves, time passes more slowly.

For a moving object, time contracts.

“Proper time” depends not only on where you are and your degree of proximity to masses; it depends also on the speed at which you move.

Introducing Proxima B 🌎

Let’s imagine a fictional planet (Proxima B) and now image you have a sister on this planet and you’re trying to figure out when to call her. You sit around thinking of what time is it on Proxima B right “now” on Earth.

So when the hell is “now” on Proxima b?

The truth of the matter is that we need to give up asking the question.

There is no special moment on Proxima b that corresponds to what constitutes the present here and now.

Pause for a moment to let this conclusion sink in. 🤯

In my opinion, it is the most astounding conclusion arrived at in the whole of contemporary physics. It simply makes no sense to ask which moment in the life of your sister on Proxima b corresponds to now. It is like asking which football team has won a basketball championship.

🤯 The notion of “the present” refers to things that are close to us, not to anything that is far away. 🤯

Our “present” does not extend throughout the universe. It is like a bubble around us.

Our sense of time only exists in the here and now. It’s not objective or universal it’s entirely local.

How far does this bubble extend?

It depends on the precision with which we determine time. If by nanoseconds, the present is defined only over a few meters; if by milliseconds, it is defined over thousands of kilometers.

As humans, we distinguish tenths of a second only with great difficulty; we can easily consider our entire planet to be like a single bubble where we can speak of the present as if it were an instant shared by us all. This is as far as we can go.                

The idea that a well-defined now exists throughout the universe is an illusion, an illegitimate extrapolation of our own experience.

Let this sink in…..

The “present of the universe” is meaningless.

Cone Shaped Time 🍦

There is a cone-shaped “past” made up of her forebears, and a “future” cone comprising her descendants.

More than a hundred years have passed since we learned that the “present of the universe” does not exist. And yet this continues to confound us and still seems difficult to conceptualize.

For centuries, we have divided time into days. The word “time” derives from an Indo-European root—di or dai—meaning “to divide.” For centuries, we have divided the days into hours.

“What is time?,” You can come to the following conclusion: time is the measurement of change.

So if nothing changes, if nothing moves, does time therefore cease to pass?

Aristotle believed that it did. If nothing changes, time does not pass—because time is our way of situating ourselves in relation to the changing of things: the placing of ourselves in relation to the counting of days.

Time is the measure of change: if nothing changes, there is no time.            

Time is only a way of measuring how things change, as Aristotle would have it—or should we be thinking that an absolute time exists that flows by itself, independently of things?

Newton’s model, based on the idea of a time independent of things, has enabled the construction of modern physics—a physics that works incredibly well.

Newton writes that this “absolute, true, and mathematical” time is not perceptible.

The existence of this Newtonian concept of time which is independent of things seems to you simple and natural, it’s because you encountered it at school.

Time as a fixed objective entity fits into our localized uniform understanding of the world. ✅✅

Because it has gradually become the way in which we all think about time. It has filtered through school textbooks throughout the world and ended up becoming our common way of understanding time.

We have turned it into our common sense.

As in the case of time, Newton suggests that we should think differently.

The space defined by Aristotle, the enumeration of what surrounds each thing, is called “relative, apparent, and common” by Newton. He calls “absolute, true, and mathematical” space in itself, which exists even where there is nothing.

The difference between Aristotle and Newton is glaring. For Newton, between two things there may also be “empty space.” For Aristotle, it is absurd to speak of “empty” space, because space is only the spatial order

Newton imagines that things are situated in a “space” that continues to exist, empty, even when divested of things. For Aristotle, this “empty space” is nonsensical, because if two things do not touch it means that there is something else between them, and if there is something, then this something is a thing, and therefore a thing that is there. It cannot be that there is “nothing.”

The existence of a complete void, without any physical entity except amorphous space, “absolute, true, and mathematical,” remains a brilliant theoretical idea introduced by Newton to found his physics on, for there is no scientific, experimental evidence to support its existence.

The answer is that the time and space Newton had intuited the existence of, beyond tangible matter, do effectively exist. They are real. Time and space are real phenomena. But they are in no way absolute; they are not at all independent from what happens; they are not as different from the other substances of the world, as Newton had imagined them to be.              

Newtonian canvas on which the story of the world is drawn. But this canvas is made of the same stuff that everything else in the world is made of, the same substance that constitutes stone, light, and air: it is made of fields. Physicists call “fields” the substances that, to the best of our knowledge, constitute the weave of the physical reality of the world.

This the key point—there is also a “gravitational” field: it is the origin of the force of gravity, but it is also the texture that forms Newton’s space and time, the fabric on which the rest of the world is drawn. Clocks are mechanisms that measure its extension. The meters used for measuring length are portions of matter that measure another aspect of its extension.

More than a drawing on a canvas, the world is like a superimposition of canvases, of strata, where the gravitational field is only one among others. Just like the others, it is neither absolute nor uniform, nor is it fixed: it flexes, stretches, and jostles with the others, pushing and pulling against

The canvas formed by the gravitational field is like a vast elastic sheet

The image above illustrates what physicists call “curved” spacetime.

Time thus becomes part of a complicated geometry woven together with the geometry of space.

There is a structure of reality that is the gravitational field; it is not separate from the rest of physics, nor is it the stage across which the world passes. It is a dynamic component of the great dance of the world, similar to all the others, interacting with the others, determining the rhythm of those things that we call meters and clocks and the rhythm of all physical phenomena. Success,

Time Only Exists On Our Scale of the Universe ⚖️

For the gravitational field, this is called the “Planck scale.” Minimum time is called “Planck time.”

It is so extremely small that we should not be astounded to discover that “down there,” at such a minute scale, the notion of time is no longer valid. Why should it be? Nothing is valid always and everywhere. Sooner or later, we always come across something that is new.

To give you some context…

The “quantization” of time implies that almost all values of time do not exist.

In other words, a minimum interval of time exists. Below this, the notion of time does not exist—even in its most basic meaning.

Time only “exist” as we know it in OUR scale. 🤯

Continuity is only a mathematical technique for approximating very finely grained things.

Once it is understood that Newton’s space and time are physical entities like all others, it is natural to suppose that they are also granular.

Quantum Indeterminacy 😕

The second discovery made by quantum mechanics is indeterminacy: it is not possible to predict exactly, for instance, where an electron will appear tomorrow. Between one appearance and another, the electron has no precise position, as if it were dispersed in a cloud of probability.

In the jargon of physicists, we say that it is in a “superposition” of positions.

In this way time or reality only exists as a wave function in a field of other “probabilities”

Even the distinction between present, past, and future thus becomes fluctuating, indeterminate. Just as a particle may be diffused in space, so, too, the differences between past and future may fluctuate: an event may be both before and after another one.

The big takeaway here is that the order of time isn’t necessarily determined or concrete. It really depends on how you look at it.

Concreteness occurs only in relation to a physical system: this, I believe, is the most radical discovery made by quantum mechanics. 🤯

When an electron collides with an object—the screen of an old television set with a cathode ray tube, for example—the cloud of probability with which we conceived of it “collapses” and the electron materializes at a point on the screen, producing one of the luminous dots that goes into the making of a TV image.

But it is only in relation to the screen that this happens. In relation to another object, the electron and screen are now together in a superposition of configurations, and it is only at the moment of further interaction with a third object that their shared cloud of probability “collapses” and materializes in a particular configuration or our reality.

It is also a quantum entity that does not have determined values until it interacts with something else. When it does, the durations are granular and determinate only for that something with which it interacts; they remain indeterminate for the rest of the universe.

The picture of spacetimes (in the plural) fluctuating, superimposed one above the other, materializing at certain times with respect to particular objects, provides us with a very vague vision. But it is the best that we have for the fine granularity of the world. We are peering into the world of quantum gravity.

Let that sink in for a moment as it’s an important consideration – our version of reality is blurred and subject to a high degree of localism. What is perceive as time and time dilation is mostly a product of relativity. 🤯

There is no objective sense of time that is shared uniformly throughout the entire universe.

There is no single time: there is a different duration for every trajectory; and time passes at different rhythms according to place and according to speed.

It is not directional: the difference between past and future does not exist in the elementary equations of the world; its orientation is merely a contingent aspect that appears when we look at things and neglect the details.

In this blurred view, the past of the universe was in a curiously “particular” state.

The notion of the “present” does not work: in the vast universe there is nothing that we can reasonably call “present.” The substratum that determines the duration of time is not an independent entity, different from the others that make up the world; it is an aspect of a dynamic field.

It jumps, fluctuates, materializes only by interacting, and is not to be found beneath a minimum scale. . . . So, after all this, what is left of time? You got to deep-six your wristwatch, you got to try and understand, The time it seems to capture is just the movement of its hands

This is the world without time.

The world is a network of events. 🕸️

Time, as Aristotle suggested, is the measure of change; different variables can be chosen to measure that change, and none of these has all the characteristics of time as we experience it.

The entire evolution of science would suggest that the best grammar for thinking about the world is that of change, not of permanence. Not of being, but of becoming.

Think Buddhism

Thinking of the world as a collection of events, of processes, is the way that allows us to better grasp, comprehend, and describe it. It is the only way that is compatible with relativity. The world is not a collection of things, it is a collection of events.

The difference between things and events is that things persist in time; events have a limited duration.

On closer inspection, in fact, even the things that are most “thinglike” are nothing more than long events.

The hardest stone, in the light of what we have learned from chemistry, from physics, from mineralogy, from geology, from psychology, is in reality a complex vibration of quantum fields, a momentary interaction of forces, a process that for a brief moment manages to keep its shape, to hold itself in equilibrium before disintegrating again into dust, a brief chapter in the history of interactions between the elements of the planet, a trace of Neolithic humanity, a weapon used by a gang of kids, an example in a book about time, a metaphor for an ontology, a part of a segmentation of the world that depends more on how our bodies are structured to perceive than on the object of perception—and, gradually, an intricate knot in that cosmic game of mirrors that constitutes reality.          

If the world were, however, made of things, what would these things be?

What works instead is thinking about the world as a network of events.

For a long time, we have tried to understand the world in terms of some primary substance. Perhaps physics, more than any other discipline, has pursued this primary substance. But the more we have studied it, the less the world seems comprehensible in terms of something that is.      

The error lies in seeking to understand the world in terms of things rather than events. It lies in ignoring change.

We understand the world in its becoming, not in its being which is in many ways beyond our ability to comprehend.                

There Is No Clock

The absence of time does not mean, therefore, that everything is frozen and unmoving. It means that the incessant happening that wearies the world is not ordered along a timeline, is not measured by a gigantic ticktocking. It does not even form a four-dimensional geometry. It is a boundless and disorderly network of quantum events.

Usually, we call “real” the things that exist now, in the present. Not those which existed once, or may do so in the future. We say that things in the past or the future “were” real or “will be” real, but we do not say they “are” real. Philosophers call “presentism” the idea that only the present is real, that the past and the future are not—and that reality evolves from one present to another, successive one.

The most we can speak of is a present relative to a moving observer. But then, what is real for me is different from that which is real for you, despite the fact that we would like to use the expression “real”—in an objective sense—as much as possible.

Let’s return to the question with which we began: What “is real”? What “exists”? The answer is that this is a badly put question, signifying everything and nothing. Because the adjective “real” is ambiguous; it has a thousand meanings. The verb “to exist” has even more.

There are so many different usages of the verb, different ways in which we can say that a thing exists: a law, a stone, a nation, a war, a character in a play, the god (or gods) of a religion to which we do not belong, the God of the religion to which we do belong, a great love, a number.

Each one of these entities “exists” and “is real” in a sense different from all the others.

Grammar developed from our limited experience, before we became aware of its imprecision when it came to grasping the rich structure of the world.

What confuses us when we seek to make sense of the discovery that no objective universal present exists is only the fact that our grammar is organized around an absolute distinction—“past/present/future”—that is only partially apt, here in our immediate vicinity. The structure of reality is not the one that this grammar presupposes. We say that an event “is,” or “has been,” or “will be.” We do not have a grammar adapted to say that an event “has been” in relation to me but “is” in relation to you.

Trippy right?

But it isn’t absence that causes sorrow. It is affection and love. Without affection, without love, such absences would cause us no pain. For this reason, even the pain caused by absence is, in the end, something good and even beautiful, because it feeds on that which gives meaning to life.

We cannot draw a complete map, a complete geometry, of everything that happens in the world, because such happenings—including among them the passage of time—are always triggered only by an interaction with, and with respect to, a physical system involved in the interaction. The world is like a collection of interrelated points of view. To speak of the world “seen from outside” makes no sense, because there is no “outside” to the world.

The elementary quanta of the gravitational field exist at the Planck scale.

The relations of spatial adjacency tie the grains of space into webs. We call these “spin networks.” The name “spin” comes from the mathematics that describe the grains of space.75 A ring in the spin network is called a “loop,” and these are the loops that give “loop theory” its name.

Note:Look this up

The occurrence of these leaps draws the patterns that on a large scale appear to us like the smooth structure of spacetime. On a small scale, the theory describes a “quantum spacetime” that is fluctuating, probabilistic, and discrete. At this scale, there is only the frenzied swarming of quanta that appear and vanish.

Note:We experience smooth time but reality is more  field of probability

In a theory of this kind, time and space are no longer containers or general forms of the world. They are approximations of a quantum dynamic that in itself knows neither space nor time. There are only events and relations. It is the world without time of elementary physics.

There are so many things that are not part of the elementary grammar of the world and that simply “emerge” in some way. For example:

a cat, a football team, high and low, the surface of clouds, the rotation of the cosmos—emerges from a world that at a much simpler level has no cats, teams, up or down, no surfaces of clouds, no revolving cosmos. . . . Time emerges from a world without time, in a way that has something in common with each of these examples.

THERMAL TIME

Between ourselves and the rest of the world there are physical interactions. Obviously, not all the variables of the world interact with us, or with the segment of the world to which we belong.

Only a very minute fraction of these variables does so; most of them do not react with us at all. They do not register us, and we do not register them.

This is why distinct configurations of the world seem equivalent to us. The physical interaction between myself and a glass of water—two pieces of the world—is independent of the motion of the single molecules of water. In the same way, the physical interaction between myself and a distant galaxy—two pieces of the world—ignores what happens in detail out there.

Therefore, our vision of the world is blurred because the physical interactions between the part of the world to which we belong and the rest are blind to many variables.

Our myopic focus on our subjective now distorts the world around us.

This does not mean that blurring is a mental construct; it depends on actual, existing physical interactions.  Entropy is not an arbitrary quantity, nor a subjective one. It is a relative one, like speed.

This, which is a fact, opens up the possibility that it wasn’t the universe that was in a very particular configuration in the past. Perhaps instead it is us, and our interactions with the universe, that are particular. We are the ones who determine a particular macroscopic description. The initial low entropy of the universe, and hence the arrow of time, may be more down to us than to the universe itself. This is the basic idea.

Everything comes down to perspective

The rotation of the heavens is a perspective effect due to our particular way of moving on Earth, rather than a mysterious property of the dynamics of the universe.

If we give a description of the world that ignores point of view, that is solely “from the outside”—of space, of time, of a subject—we may be able to say many things but we lose certain crucial aspects of the world. Because the world that we have been given is the world seen from within it, not from without. Many things that we see in the world can be understood only if we take into account the role played by point of view.

They remain unintelligible if we fail to do so. In every experience, we are situated within the world: within a mind, a brain, a position in space, a moment in time.

In order to use a geographical map, it is not enough to look at it from the outside: we must know where we are situated in relation to what it represents. In order to understand our experience of space, it is not enough to think of Newtonian space. We must remember that we see this space from inside it, that we are localized. In order to understand time, it is not enough to think of it from outside: it is necessary to understand that we, in every moment of our experience, are situated within time.

We observe the universe from within it, interacting with a minuscule portion of the innumerable variables of the cosmos. What we see is a blurred image. This blurring suggests that the dynamic of the universe with which we interact is governed by entropy, which measures the amount of blurring. It measures something that relates to us more than to the cosmos.

A Quick Visit Back to Entropy ⭐

It is the growth of this entropy that powers the great story of the cosmos.

The entire coming into being of the cosmos is a gradual process of disordering, like the pack of cards that begins in order and then becomes disordered through shuffling. There are no immense hands that shuffle the universe. It does this mixing by itself, in the interactions among its parts that open and close during the course of the mixing, step by step. Vast regions remain trapped in configurations that remain ordered, until here and there new channels are opened through which disorder spreads.  What causes events to happen in the world, what writes its history, is the irresistible mixing of all things, going from the few ordered configurations to the countless disordered ones. The entire universe is like a mountain that collapses in slow motion. Like a structure that very gradually crumbles.

It is the presence of abundant traces of the past that produces the familiar sensation that the past is determined.

Absence of any analogous traces of the future produces the sensation that the future is open. The existence of traces serves to make it possible for our brain to dispose of extensive maps of past events. There is nothing analogous to this for future ones. This fact is at the origin of our sensation of being able to act freely in the world: choosing between different futures, even though we are unable to act upon the past.

We are processes, events, composite and limited in space and time. But if we are not an individual entity, what is it that founds our identity and its unity?

3 Ingredients of the Time Recipe 🍲

There are different ingredients that combine to produce our identity. Three of these are important for the argument of this book:

The first is that every one of us identifies with a point of view in the world. Each of us is a complex process that reflects the world and elaborates the information we receive in a way that is strictly integrated.  

The second ingredient on which our identity is based is the same as for the chariot. In the process of reflecting the world, we organize it into entities: we conceive of the world by grouping and segmenting it as best we can in a continuous process that is more or less uniform and stable, the better to interact with it.

We establish boundaries, we approximate the world by breaking it down into pieces. It is the structure of our nervous system that works in this way. It receives sensory stimuli, elaborates information continuously, generating behavior.

It does so through networks of neurons, which form flexible dynamic systems that continuously modify themselves, seeking to predict—as far as possible—the flow of information intake.

If this is so, then “things,” like “concepts,” are fixed points in the neuronal dynamic, induced by recurring structures of the sensorial input and of the successive elaborations.

We have shaped an idea of a “human being” by interacting with others like ourselves. I believe that our notion of self stems from this, not from introspection.

We are for ourselves in large measure what we see and have seen of ourselves reflected back to us by our friends, our loves, and our enemies.

Third ingredient in the foundation of our identity, and it is probably the essential one—it is the reason this delicate discussion is taking place in a book about time: memory.

I am this long, ongoing novel. My life consists of it.

It is memory that solders together the processes, scattered across time, of which we are made. In this sense we exist in time.

To understand ourselves means to reflect on time. But to understand time we need to reflect on ourselves.

To a large extent, the brain is a mechanism for collecting memories of the past in order to use them continually to predict the future.

The possibility of predicting something in the future obviously improves our chances of survival and, consequently, evolution has selected the neural structures that allow it. We are the result of this selection. This being between past and future events is central to our mental structure. This, for us, is the “flow” of time.

It is within my mind, then, that I measure time. I must not allow my mind to insist that time is something objective. When I measure time, I am measuring something in the present of my mind. Either this is time, or I have no idea what time is.

And hence this is what time is: it is entirely in the present, in our minds, as memory and as anticipation.

But he also observes that whereas space is shaped by our external sense, that is to say, by our way of ordering things that we see in the world outside of us, time is shaped by our internal sense, that is to say, by our way of ordering internal states within ourselves.

Time, then, is the form in which we beings, whose brains are made up essentially of memory and foresight, interact with the world: it is the source of our identity. And of our suffering as well.

Birth is suffering, decline is suffering, illness is suffering, death is suffering, union with that which we hate is suffering, separation from that which we love is suffering, failure to obtain what we desire is suffering.

It’s suffering because we must lose what we have and are attached to. Because everything that begins must end.

What causes us to suffer is not in the past or the future: it is here, now, in our memory, in our expectations. We long for timelessness, we endure the passing of time: we suffer time. Time is suffering.

Because it is nothing but a fleeting structure of the world, an ephemeral fluctuation in the happening of the world, that which is capable of giving rise to what we are: beings made of time.

That to which we owe our being, giving us the precious gift of our very existence, allowing us to create the fleeting illusion of permanence that is the origin of all our suffering.

At the end this book comes down to this one simple idea….

In the end, therefore, instead of many possible times, we can speak only of a single time: the time of our experience—uniform, universal, and ordered. This is the approximation of an approximation of an approximation of a description of the world made from our particular perspective as human beings who are dependent on the growth of entropy, anchored to the flowing of time.

The temporal structure of the world is different from the naïve image that we have of it. This naïve image is suitable for our daily life, but it’s not suitable for understanding the world in its minute folds, or in its vastness.

And we begin to see that we are time. We are this space, this clearing opened by the traces of memory inside the connections between our neurons. We are memory. We are nostalgia. We are longing for a future that will not come. The clearing that is opened up in this way, by memory and by anticipation, is time: a source of anguish sometimes, but in the end a tremendous gift. A precious miracle that the infinite play of combinations has unlocked for us, allowing us to exist. We may smile now. We can go back to serenely immersing ourselves in time—in our finite time—to savoring the clear intensity of every fleeting and cherished moment of the brief circle of our existence.