Carlo Rovelli Time Quotes

In his youth Albert Einstein spent a year loafing aimlessly. You don't get anywhere by not 'wasting' time- something, unfortunately, that the parents of teenagers tend frequently to forget.

This is time for us. Memory. A nostalgia. The pain of absence. 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.

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.

The atoms of our body, as well, flow in and away from us. We, like waves and like all objects, are a flux of events; we are processes, for a brief time monotonous

It is like the point where the rainbow touches the forest. We think that we can see it—but if we go to look for it, it isn’t there.

The ability to understand something before it’s observed is at the heart of scientific thinking.

If I ask whether two events—one on Earth and the other on Proxima b—are happening “at the same moment,” the correct answer would be: “It’s a question that doesn’t make sense, because there is no such thing as ‘the same moment’ definable in the universe.” The “present of the universe” is meaningless.

All of the sons of Adam are part of one single body, They are of the same essence. When time afflicts us with pain In one part of that body All the other parts feel it too. If you fail to feel the pain of others You do not deserve the name of man.

There are frontiers where we are learning, and our desire for knowledge burns. They are in the most minute reaches of the fabric of space, at the origins of the cosmos, in the nature of time, in the phenomenon of black holes, and in the workings of our own thought processes. Here, on the edge of what we know, in contact with the ocean of the unknown, shines the mystery and the beauty of the world. And it’s breathtaking.

It is entropy, not energy, that keeps stones on the ground and the world turning.

I am my mother’s caresses, and the serene kindness with which my father calmly guided me; I am my adolescent travels; I am what my reading has deposited in layers in my mind; I am my loves, my moments of despair, my friendships, what I’ve written, what I’ve heard; the faces engraved on my memory. I am, above all, the one who a minute ago made a cup of tea for himself. The one who a moment ago typed the word “memory” into his computer. The one who just composed the sentence that I am now completing. If all this disappeared, would I still exist? I am this long, ongoing novel. My life consists of it.

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.

Nature is our home, and in nature we are at home. This strange, multicoloured and astonishing world which we explore – where space is granular, time does not exist, and things are nowhere – is not something that estranges us from our true selves, for this is only what our natural curiosity reveals to us about the place of our dwelling. About the stuff of which we ourselves are made.

Before Newton, time for humanity was the way of counting how things changed. Before him, no one had thought it possible that a time independent of things could exist. Don't take your intuitions and ideas to be 'natural': they are often the products of the ideas of audacious thinkers who came before us.

Temporality is profoundly linked to blurring. The blurring is due to the fact that we are ignorant of the microscopic details of the world. The time of physics is, ultimately, the expression of our ignorance of the world. Time is ignorance.

Things change only in relation to one another. At a fundamental level, there is no time.

We inhabit time as fish live in water. Our being is being in time.

I believe that our species will not last long. It does not seem to be made of the stuff that has allowed the turtle, for example, to continue to exist more or less unchanged for hundreds of millions of years, for hundreds of times longer, that is, than we have even been in existence. We belong to a short-lived genus of species. All of our cousins are already extinct. What's more, we do damage. The brutal climate and environmental changes that we have triggered are unlikely to spare us.

O gentlemen, the time of life is short . . . And if we live, we live to tread on kings. Shakespeare, Henry IV, Part I (act 5, scene 2)

We can think of the world as made up of things. Of substances. Of entities. Of something that is. Or we can think of it as made up of events. Of happenings. Of processes. Of something that occurs. Something that does not last, and that undergoes continual transformation, that is not permanent in time.

Past and future are different from each other. Cause precedes effect. Pain comes after a wound, not before it. The glass shatters into a thousand pieces, and the pieces do not re-form into a glass. We cannot change the past; we can have regrets, remorse, memories. The future instead is uncertainty, desire, anxiety, open space, destiny, perhaps. We can live toward it, shape it, because it does not yet exist. Everything is still possible... Time is not a line with two equal directions: it is an arrow with different extremities.

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. It’s a conclusion that leaves us flabbergasted: 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? Is it true that, if I could see exactly and take into consideration the actual dance of millions of molecules, then the future would be “just like” the past?

As human beings, we live by emotions and thoughts. We exchange them when we are in the same place at the same time, talking to each other, looking into each other's eyes, brushing against each other's skin. We are nourished by this network of encounters and exchanges. But, in reality, we do not need to be in the same place and time to have such exchanges. Thoughts and emotions that create bonds of attachment between us have no difficulty in crossing seas and decades, sometimes even centuries, tied to thin sheets of paper or dancing between the microchips of a computer. We are part of a network that goes far beyond the few days of our lives and the few square meters that we tread. This book is also a part of that weave...

I remember a little girl... But how can that be... Once I was that little Resi, and then one day I became an old woman? ...If God wills it so, why allow me to see it? Why doesn't he hide it from me? Everything is a mystery, such a deep mystery... I feel the fragility of things in time. From the bottom of my heart, I feel we should cling to nothing. Everything slips through our fingers. All that we seek to hold on to dissolves. Everything vanishes, like mist and dreams... Time is a strange thing. When we don't need it, it is nothing. Then, suddenly, there is nothing else. It is everywhere around us. Also within us. It seeps into our faces. It seeps into the mirror, runs through my temples... Between you and I it runs silently, like an hourglass. Oh, Quin Quin. Sometimes I feel it flowing inexorably. Sometimes I get up in the middle of the night and stop all the clocks...

The world, particles, light, energy, space, and time—all of this is nothing but the manifestation of a single type of entity: covariant quantum fields.

For everything that moves, time passes more slowly.

How long is forever?” asks Alice. “Sometimes, just one second,” replies the White Rabbit. There are dreams lasting an instant in which everything seems frozen for an eternity.

Things” in themselves are only events that for a while are monotonous

A moving object therefore experiences a shorter duration than a stationary one: a watch marks fewer seconds, a plant grows more slowly, a young man dreams less. For a moving object, time contracts.

I do not fear death. I fear suffering. And I fear old age, though less so now that I am witnessing the tranquil and pleasant old age of my father. I am afraid of frailty, and of the absence of love. But death does not alarm me. It did not scare me when I was young, and I thought at the time that this was because it was such a remote prospect. But now, at sixty, the fear has yet to arrive. I love life, but life is also struggle, suffering, pain. I think of death as akin to a well-earned rest.

A stone is a prototypical “thing”: we can ask ourselves where it will be tomorrow. Conversely, a kiss is an “event.” It makes no sense to ask where the kiss will be tomorrow. The world is made up of networks of kisses, not of stones.

Children grow up and discover that the world is not as it seemed from within the four walls of their homes. Humankind as a whole does the same.

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.

We are the products of a long selection process of chemical, biological, and cultural structures that at different levels have interacted for a long time in order to shape the funny process that we are.

The heat of black holes is like the Rosetta stone of physics, written in a combination of three languages- quantum, gravitational, and thermodynamic- still awaiting decipherment in order to reveal the true nature of time.

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.

If things fall, it is due to this slowing down of time. Where time passes uniformly, in interplanetary space, things do not fall. They float, without falling. Here on the surface of our planet, on the other hand, the movement of things inclines naturally toward where time passes more slowly, as when we run down the beach into the sea and the resistance of the water on our legs makes us fall headfirst into the waves. Things fall downward because, down there, time is slowed by the Earth.

Those who defend this way of thinking about reality—eternalism—frequently cite Einstein, who in a famous letter writes: For people like us who believe in physics the distinction between past, present and future is only a stubbornly persistent illusion.

An elementary structure of the world is emerging, generated by a swarm of quantum events, where time and space do not exist. Quantum fields draw together space, time, matter, and light, exchanging information between one event and another. Reality is a network of granular events; the dynamic that connects them is probabilistic; between one event and another, space, time, matter, and energy melt into a cloud of probability.

Time is information we don't have. Time is our ignorance.

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.

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

Scientific answers are not definitive: they are, almost by definition, the best ones that we have at any given time. Consider

The world is not a collection of things, it is a collection of events.

Newton’s mechanics, Maxwell’s equations, quantum mechanics, and so on, tell us how events happen, not how things are.

Every day countless people die, and yet those who remain live as if they were immortals.

Time, as Aristotle suggested, is the measure of change;

None of the pieces that time has lost (singularity, direction, independence, the present, continuity) puts into question the fact that the world is a network of events. On the one hand, there was time, with its many determinations; on the other, the simple fact that nothing is: things happen.

Time opens up our limited access to the world. 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 identity.

As human beings, we live by emotions and thoughts. We exchange them when we are in the same place at the same time, talking to each other, looking into each other’s eyes, brushing against each other’s skin. We are nourished by this network of encounters and exchanges. But, in reality, we do not need to be in the same place and time to have such exchanges. Thoughts and emotions that create bonds of attachment between us have no difficulty in crossing seas and decades, sometimes even centuries, tied to thin sheets of paper or dancing between the microchips of a computer. We are part of a network that goes far beyond the few days of our lives and the few square meters that we tread. This book is also a part of that weave. . .

Every moment of our existence is linked by a peculiar triple thread to our past—the most recent and the most distant—by memory. Our present swarms with traces of our past. We are histories of ourselves, narratives. I am not this momentary mass of flesh reclined on the sofa typing the letter a on my laptop; I am my thoughts full of the traces of the phrases that I am writing; I am my mother’s caresses, and the serene kindness with which my father calmly guided me; I am my adolescent travels; I am what my reading has deposited in layers in my mind; I am my loves, my moments of despair, my friendships, what I’ve written, what I’ve heard; the faces engraved on my memory. I am, above all, the one who a minute ago made a cup of tea for himself. The one who a moment ago typed the word “memory” into his computer. The one who just composed the sentence that I am now completing. If all this disappeared, would I still exist? I am this long, ongoing novel. My life consists of it.

The entropy of a system depends explicitly on blurring. It depends on what I do not register, because it depends on the number of indistinguishable configurations. The same microscopic configuration may be of high entropy with regard to one blurring and of low in relation to another.

Change is ubiquitous. Only: elementary processes cannot be ordered along a common succession of instants. At the extremely small scale of the quanta of space, the dance of nature does not develop to the rhythm kept by the baton of a single orchestral conductor: every process dances independently with its neighbours, following its own rhythm. The passing of time is intrinsic to the world, it is born of the world itself, out of the relations between quantum events which are the world and which themselves generate their own time.

Abstract thought can anticipate by centuries hypotheses that find a use—or confirmation—in scientific inquiry.

We long for timelessness, we endure the passing of time: we suffer time. Time is suffering.

But the world is a quantum one, and gelatinous spacetime is also an approximation.

Aristotle is the first we are aware of to have asked himself the question “What is time?,” and he came to the following conclusion: time is the measurement of change.

Time passes more slowly for the one who keeps moving.

For a hypothetically supersensible being, there would be no “flowing” of time: the universe would be a single block of past, present, and future.

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.

Scientists are not immune from talking nonsense.

The events of the world do not form an orderly queue, like the English. They crowd around chaotically, like Italians.

we understand the world by studying change, not by studying things.

Our fear of death seems to me to be an error of evolution.

Don’t take your intuitions and ideas to be “natural”: they are often the products of the ideas of audacious thinkers who came before us.

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.

I chose as my supervisor a professor who allowed me to continue to study what I wanted.

Fearing the transition, being afraid of death, is like being afraid of reality itself; like being afraid of the sun. Whatever for?

The mystery of time has always troubled us, stirring deep emotions. So deep as to have nourished philosophies and religions.

But this does not imply that we cannot or must not trust our own thinking. To the contrary: our own thinking is the best tool we have for finding our way in this world. Recognizing its limitations does not imply that it is not something to rely upon. If instead we trust in “tradition” more than in our own thinking, for instance, we are only relying on something even more primitive and uncertain than our own thinking. “Tradition” is nothing else than the codified thinking of human beings who lived at times when ignorance was even greater than ours.

Such is time, and because of this we are fascinated and troubled by it in equal measure-and perhaps because of this, too, dear reader, my brother, my sister, you are holding this book in your hands. 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.

And it seems to me that life, this brief life, is nothing other than this: the incessant cry of these emotions that drive us, that we sometimes attempt to channel in the name of a god, a political faith, in a ritual that reassures us that, fundamentally, everything is in order, in a great and boundless love—and the cry is beautiful. Sometimes it is a cry of pain. Sometimes it is a song.

It is in order to escape this anxiety that we have imagined the existence of “eternity,” a strange world outside of time that we would like to be inhabited by gods, by a God, or by immortal souls.

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.

Music can occur only in time, but if we are always in the present moment, how is it possible to hear it? It is possible, Augustine observes, because our consciousness is based on memory and on anticipation.

Perhaps the rivers of ink that have been expended discussing the nature of the “continuous” over the centuries, from Aristotle to Heidegger, have been wasted. Continuity is only a mathematical technique for approximating very finely grained things. The world is subtly discrete, not continuous. The good Lord has not drawn the world with continuous lines: with a light hand, he has sketched it in dots, like the painter Georges Seurat.

The entropy of the world in the far past appears very low to us. But this might not reflect the exact state of the world: it might regard the subset of the world' s variables with which we, as physical systems, have interacted. It is with respect to the dramatic blurring produced by our interactions with the world, caused by the small set of macroscopic variables in terms of which we describe the world, that the entropy of the universe was low.

The world is in a ceaseless process of change. 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. We can think of the world as made up of things, of substances, of entities, of something that is, or we can think of it as made up of events, of happenings, of processes, of something that occurs, something that does not last, and undergoes continual transformation that is not permanent in time.

It follows that the notion of certain configurations being more particular than others (twenty-six red cards followed by twenty-six black, for example) makes sense only if I limit myself to noticing only certain aspects of the cards (in this case, the colors). If I distinguish between all the cards, the configurations are all equivalent: none of them is more or less particular than others.18 The notion of “particularity” is born only at the moment we begin to see the universe in a blurred and approximate way.

A science that closes its ears to philosophy fades into superficiality; a philosophy that pays no attention to the scientific knowledge of its time is obtuse and sterile. It betrays its own deepest roots, which are evident in the etymology of philosophy: the love of knowledge.

There is no “truer” time; there are two times and they change relative to each other. Neither is truer than the other. 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.

(Even the attribution of the idea to Descartes seems wrong to me: Cogito ergo sum is not the first step in the Cartesian reconstruction, it is the second. The first is Dubito ergo cogito. The starting point of the reconstruction is not a hypothetical a priori that is immediate to the experience of existing as a subject. It’s a rationalistic a posteriori reflection on the first stage of the process in which Descartes had articulated a state of doubt: logic dictates that if someone doubts something, they must have thought about it. And that if they can think, then they must exist.

Physics opens windows through which we see far into the distance. What we see does not cease to astonish us. We realize that we are full of prejudices and that our intuitive image of the world is partial, parochial, inadequate. Earth is not flat; it is not stationary. The world continues to change before our eyes as we gradually see it more extensively and more clearly. If we try to put together what we have learned in the twentieth century about the physical world, the clues point toward something profoundly different from our instinctive understanding of matter, space, and time.

Is the daily spectacle of a revolving universe “illusory”? No, it is real, but it doesn’t involve the cosmos alone. It involves our relation with the sun and the stars. We understand it by asking ourselves how we move. Cosmic movement emerges from the relation between the cosmos and ourselves.

But it is not only space that curves: time does too. Einstein predicts that time on Earth passes more quickly at higher altitude, and more slowly at lower altitude. This is measured, and also proves to be the case. Today we have extremely precise clocks, in many laboratories, and it is possible to measure this strange effect even for a difference in altitude of just a few centimeters. Place a watch on the floor and another on a table: the one on the floor registers less passing of time than the one on the table. Why? Because time is not universal and fixed; it is something that expands and shrinks, according to the vicinity of masses: Earth, like all masses, distorts spacetime, slowing down time in its vicinity. Only slightly—but two twins who have lived respectively at sea level and in the mountains will find that, when they meet up again, one will have aged more than the other

We can see the world without time: we can perceive with the mind’s eye the profound structure of the world where time as we know it no longer exists—like the Fool on the Hill who sees the Earth turn when he sees the setting sun. 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.

[S]ong, as Augustine observed, is the awareness of time. It is time. It is the hymn of the Vedas that is itself the flowering of time. In the Benedictus of Beethoven’s Missa Solemnis, the song of the violin is pure beauty, pure desperation, pure joy. We are suspended, holding our breath, feeling mysteriously that this must be the source of meaning. That this is the source of time. Then the song fades and ceases. “The silver thread is broken, the golden bowl is shattered, the amphora at the fountain breaks, the bucket falls into the well, the earth returns to dust.” And it is fine like this. We can close our eyes, rest. This all seems fair and beautiful to me. This is time.

In the elementary equations of the world,13 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.

In The Order of Time, physicist and author Carlo Rovelli sums up this dynamic beautifully: "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.

Empowered by new conceptual tools and by mathematics, Einstein writes the equations which describe Democritus’s void and finds for its ‘certain physics’ a colourful and amazing world where universes explode, space collapses into bottomless holes, time slows down in the vicinity of a planet, and the boundless expanses of interstellar space ripple and sway like the surface of the sea

Augustine’s exposition of the idea is quite beautiful. It is based on our experience of music. When we listen to a hymn, the meaning of a sound is given by the ones that come before and after it. Music can occur only in time, but if we are always in the present moment, how is it possible to hear it? It is possible, Augustine observes, because our consciousness is based on memory and on anticipation.

In the elementary equations of the world,13 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. If I watch a film that shows a ball rolling, I cannot tell if the film is being projected correctly or in reverse. But if the ball stops, I know that it is being run properly; run backward, it would show an implausible event: a ball starting to move by itself. The ball’s slowing down and coming to rest are due to friction, and friction produces heat. Only where there is heat is there a distinction between past and future. Thoughts, for instance, unfold from the past to the future, not vice versa—and, in fact, thinking produces heat in our heads. . . .

Too often scientists sell hypothetical theories to the large public, as if they were established theories. I have seen this often done, for instance, with string theory. I think this is a great mistake, because it questions the credibility itself of science. We scientists live out of public money and it is our duty to be fully honest in reporting what we know and what we do not know. We are paid to dream, but we must not sell our dreams for established realities.

If LISA is launched, it should be able to see not only the gravitational waves produced by stars and black holes but also the diffuse background of primordial gravitational waves generated at a time close to the Big Bang. These waves should tell us about the quantum bounce. In the subtle irregularities of space, we should be able to find traces of events that took place fourteen billion years ago, at the origin of our universe, and confirm our deductions on the nature of space and time.

I believe that our species will not last long. It does not seem to be made of the stuff that has allowed the turtle, for example, to continue to exist more or less unchanged for hundreds of millions of years, for hundreds of times longer, that is, than we have even been in existence. We belong to a short-lived genus of species. All of our cousins are already extinct. What’s more, we do damage. The brutal climate and environmental changes that we have triggered are unlikely to spare us. For Earth they may turn out to be a small irrelevant blip, but I do not think that we will outlast them unscathed—especially since public and political opinion prefers to ignore the dangers that we are running, hiding our heads in the sand. We are perhaps the only species on Earth to be conscious of the inevitability of our individual mortality. I fear that soon we shall also have to become the only species that will knowingly watch the coming of its own collective demise, or at least the demise of its civilization.

A mechanism in the box opens the small window on the right for an instant, allowing a photon to escape at some precise time. By weighing the box, it is possible to deduce the energy of the released photon. Einstein hoped that thus would create difficulties for quantum mechanics, which predicts that time and energy cannot both be precisely determined. Bohr replied, mistakenly, that the way out of the difficulty required Einstein's general relativity, and Einstein, mistakenly, accepted Bohr's reply. The correct response to Einstein, that Bohr was unable to find but is clear today, is that the position of the escaping photon and the weight of the box remain tied to each other ("correlated") even if the photon is already far away.

The entropy of the world in the far past appears very low to us. But this might not reflect the exact state of the world: it might regard the subset of the world’s variables with which we, as physical systems, have interacted. It is with respect to the dramatic blurring produced by our interactions with the world, caused by the small set of macroscopic variables in terms of which we describe the world, that the entropy of the universe was low. 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.

What works instead is thinking about the world as a network of events. Simple events, and more complex events that can be disassembled into combinations of simpler ones. A few examples: a war is not a thing, it’s a sequence of events. A storm is not a thing, it’s a collection of occurrences. A cloud above a mountain is not a thing, it is the condensation of humidity in the air that the wind blows over the mountain. A wave is not a thing, it is a movement of water, and the water that forms it is always different. A family is not a thing, it is a collection of relations, occurrences, feelings. And a human being? Of course it’s not a thing; like the cloud above the mountain, it’s a complex process, where food, information, light, words, and so on enter and exit. . . . A knot of knots in a network of social relations, in a network of chemical processes, in a network of emotions exchanged with its own kind.

And it seems to me that life, this brief life, is nothing other than this: the incessant cry of these emotions that drive us, that we sometimes attempt to channel in the name of a god, a political faith, in a ritual that reassures us that, fundamentally, everything is in order, in a great and boundless love—and the cry is beautiful. Sometimes it is a cry of pain. Sometimes it is a song. And song, as Augustine observed, is the awareness of time. It is time. It is the hymn of the Vedas that is itself the flowering of time.131 In the Benedictus of Beethoven’s Missa Solemnis, the song of the violin is pure beauty, pure desperation, pure joy. We are suspended, holding our breath, feeling mysteriously that this must be the source of meaning. That this is the source of time. Then the song fades and ceases. “The silver thread is broken, the golden bowl is shattered, the amphora at the fountain breaks, the bucket falls into the well, the earth returns to dust.”132 And it is fine like this. We can close our eyes, rest. This all seems fair and beautiful to me. This is time.

The idea of thermal time reverses this observation. That is to say, instead of inquiring how time produces dissipation in heat, it asks how heat produces time. Thanks to Boltzmann, we know that the notion of heat comes from the fact that we interact with averages. The idea of thermal time is that the notion of time, as well, comes from the fact that we interact only with averages of many variables.* As long as we have a complete description of a system, all the variables of the system are on the same footing; none of them act as a time variable. That is to say, none is correlated to irreversible phenomena. But as soon as we describe the system by means of averages of many variables, we have a preferred variable that functions like common time. A time along which heat dissipates. The time of our everyday experience. Hence time is not a fundamental constituent of the world, but it appears because the world is immense, and we are small systems within the world, interacting only with macroscopic variables that average among innumerable small, microscopic variables. We, in our everyday lives, never see a single elementary particle, or a single quantum of space. We see stones, mountains, the faces of our friends—and each of these things we see is formed by myriads of elementary components. We are always correlated with averages. Averages behave like averages: they disperse heat and, intrinsically, generate time.