Time to Think: Carlo Rovelli on the Mysteries of Time

The Order of Time is a little wonder of a book. It provides surprising insights into an increasingly mysterious world, offers warmly humane reflections on our existential condition, and sustains a virtual conversation that will continue long after the reading has ceased.

The Order of Time
Carlo Rovelli
May 2018

I sit on the banks of the river on a particularly orderly day holding a pocket watch that used to belong to my grandmother in the palm of my hand, attending to the fateful footfalls of the second hand as it marches its resolutely circular path around the face of the watch. The waves of water lap gently at the stone one which I rest my feet. These things establish (or better, I note) their own regular rhythm in a fascinating hemiola with the ticking of my grandmother’s watch—for every eight seconds there are three waves knocking on the shore. Above, stray gulls pass overhead every 32 seconds (they are very precise gulls, indeed); to my right and slightly above my head, a sparrow chirps every 16 seconds. Everything seems to coordinate in a glorious symphony of recurrence and patterning and it all revolves around the assured conductor’s beat of the second hand of my grandmother’s watch. Time orders all.

Except… there’s no reason the watch should take pride of place. It doesn’t own time or have any privileged access to it over and above the other oscillations and repetitions I have noted. One gull passing = 2 sparrow chirps = 24 waves lapping = 32 ticks of the second hand. Sure, we are accustomed to measuring other durations against the second hand but in this fantasy of a perfectly ordered day, I could just as easily measure the movements of the watch hands by the recurrence of the sparrow chirps or the lapping of the waves. In one sense, the appearances of the gulls are the conductor’s downbeats, the other oscillations mere subdivisions of their established tempo. These are equivalencies and thus there’s no clear hierarchy in the same way that 566 colones (Costa Rican currency) equals one US dollar. There’s no value independent of these two things on either side of the equals sign; they are relative to each other. We might like to ground our sense of value in the “gold standard” but that just adds another relative (and ultimately arbitrary) value; it grounds nothing.

The same applies to time. The second hand is not in a naturally privileged position with respect to the resounding repetitions I’m hearing; its privilege derives from us—it’s our favored tool, reliable according to our needs in part because we feel it’s more predictably regular in its oscillations than a sparrow chirp or other phenomena tend to be. But time doesn’t “run” through the clock or watch. The clock isn’t measuring time; it’s merely performing its set of oscillations that roughly correlate to the solar day (more or less, the interval from noon to noon)—and it’s a rough approximation. Every four years we have a leap year to account for a slippage between our year and the actual interval involved in one revolution of the earth around the sun, and we also have, from time to time, a “leap second”—we are not notified of these and probably never notice them. Time is a set of relations, sort of like filiation. There’s no thing I can point to that is “fraternity” as such; Brent and Wes Jenkins stand in a certain relation to me and are thus my brothers. Without the relationship, there is no “brotherhood”; without the set of relationships among moving things, there is no time.


Except… things are not even that simple, as we learn in a riveting and occasionally frustrating new book by the renowned scientist Carlo Rovelli, entitled The Order of Time. Rovelli has emerged into the popular consciousness in recent years owing to his publications on science for the general reading public. His earlier books, Seven Brief Lessons on Physics (2016) and Reality Is Not What It Seems (2017), are widely celebrated and he has quickly become a public scientist along the lines of Stephen Hawking or Neil deGrasse Tyson. Unlike those luminaries, however, Rovelli has a strong fondness for philosophy, which he combines with an appealing humanist embrace of literature, popular culture, and wit in his writing. In The Order of Time, each chapter opens with an epigraph from the poetry of Horace; there are allusions to the lyrics of the Grateful Dead alongside references to ancient myth, Proust, Aristotle, Augustine, the Bible, the Mahabharata, and Martin Heidegger (Rovelli is just a tad disparaging toward the latter although he seems to recognize that they share many concerns and manners of approaching the issue of time). This eclectic and companionate manner of presentation makes the recondite subject matter both engaging and manageable for the non-specialist reader for whom the book is clearly designed.

However, one of the discomfiting qualities of “popular science” writings is the fact that they appear to skeptical non-specialist readers to be rather similar in kind to science fiction writing. Throughout The Order of Time, Rovelli reminds us that it might seem natural to think we see the sun rising and setting but we know that in reality this is not the case; the earth is revolving while the sun is more or less stationary. Likewise, Rovelli claims, we experience time as a more or less uniform flow that pervades the universe and runs inexorably from the past toward the future but that doesn’t mean that this accounts for what time is in reality, outside of our mere perception of it. It’s a fine gambit, but as Rovelli himself acknowledges (which not all authors of popular science do), some of what’s presented here has not been established as provable fact. Rovelli asserts that these claims seem the mostly likely explanations regarding time we have at the moment and thus they are not merely fiction. One might counter that good science fiction writers provide seemingly plausible explanations as well. The most one can hope for is an author that “plays fair” with his audience and this Rovelli most certainly does. We are always made aware of which qualities of time have been demonstrated and which involve well-founded speculation.

The book is organized into three main sections. The first dismantles, one by one, our typical conception of time. The second attempts to construct an alternative view of time building on Rovelli’s own area of research. The third and final section rebuilds time as we perceive it in an attempt to come to grips with our relationship to it. If we have misconstrued time in its essence, why is that? What do we get out of such a misconstrual?

Rovelli is a major figure in a subfield of physics known as Loop quantum gravity (LQG), which, like string theory but in a more modest (and Rovelli argues, more plausible) manner, attempts to reconcile quantum mechanics and Einstein’s theory of relativity. Einstein proposed that gravity operates in a quite different manner than the forces of the subatomic particles and the overarching problem since the formulation of quantum mechanics has been to bridge the operations of things on the large scale (the universe, solar systems, and gravity) with the operation of things on the small scale (the atom, electrons, and particles). LPG attempts to create a quantum theory of gravity and asserts, among other things, that space and time are quantized; that is, they are granular, they have particles and space-time is not some smooth, continuous field that pervades and constructs the universe. Space-time is composed of exceedingly small, discrete units.

So here’s another way in which time may not at all resemble what we think it to be. While most of us recognize that the clock somewhat arbitrarily chops time into semi-discrete units (minutes or seconds in most practical situations) and we assume that really time is an unending, indivisible stream (a flow), Rovelli suggests that it is indeed composed of discrete units. So, time is relative and composed of very small but indivisible units. We can easily recognize the former property and easily ignore the latter (because it is impossible to detect) and so the universe marches on.

Except… time is not the same everywhere. Rovelli opens his book with this concern. Time passes more slowly the nearer we are to large masses, such as Earth. Thus, your watch hands actually move faster when you are in the mountains than when you are near the sea. It’s a fractional difference, but it’s there (and verifiable by examining atomic clocks). Also, moving objects age slower than objects staying still. (One apparent take-away from Rovelli’s book is that we should all live at sea-level and run everywhere we go if we aim for longevity.) While these are mere curiosities here on Earth (I won’t live noticeably longer, despite my joke, by staying low and running constantly), they wreak havoc on any conception we might have for a Universal Time in the universe. When experience is stretched out across galaxies, there is no shared Now for those of us here and creatures living on a far-off planet. This is another way in which time is relative; it’s relative to our position in the universe and is not a shared property pervading that universe. Each thing moves in its own way from its past, through its present, and into its future.

Except… and this one is the hardest for me to digest, Rovelli claims that time in its own right has no directionality. It doesn’t need to move from the past to the future. Rovelli discusses this subject in Chapter 2, “Loss of Direction”, and I will admit it felt a little early in the book for this counterintuitive claim. And yet, it had to be early in the book, because so much of what follows (even if only implicitly) relies upon accepting this revelation. Rovelli’s explanation is clever and admirable but I would be playing false if I proclaimed I fully understand it in the manner Rovelli clearly intends. Here is the argument in a nutshell. The elementary laws of mechanics fail to stipulate direction except those involving heat. Heat is always transferred in one direction (from the relatively hot to the relatively cold) and not backwards. This involves entropy, which always increases and cannot decrease; and entropy denotes disorder. The cool molecules were in a certain order, the heat agitates them and they become disordered. Fair enough. So, our belief that we are heading into the future depends upon our recognition of increasing disorder.

But now, Rovelli instructs, imagine a deck of cards. I buy a new deck and the cards are grouped in numerical order and according to suit. I shuffle the cards and that order dissipates; the cards are mixed up; the past stands as an Edenic moment of order and the future fall to entropy (and we can further our debasement by gambling). But wait… Look at the cards in the deck now and you are bound to notice a new order. It may be a more complicated order but it is an order all the same. Any order is an order. The initial one is privileged in part because it was first and because we are more accustomed to thinking of numerical ordering as a simpler, more rational ordering. But that has to do with us and our manner of perceiving the world, not with anything inherent in the cards.

In our minds, time progresses from past to future because we are entropy-tracking machines. Our world crumbles ineluctably and we measure the inevitable alteration as decline—the falling away of what once was. This becomes a central concern in the third part of The Order of Time and it leads to some fascinating reflections on the human concern with time, aging, memory, and death. Ther’is something rather illuminating about human nature that becomes manifest in focusing on the vicissitudes of memory. We are born into a world with the deck ordered in a certain manner; events occur, reshuffling the deck. We recognize that reshuffling as a relative disordering. This is a wonderful way to account for nostalgia, elements of regret, the generation gap, and so many other deeply human aspects of our existence. In this manner, the fact that my opening scenario involved my grandmother’s pocket watch reveals its significance. I don’t simply measure time as a means of navigating the objective world. Rather my sense of time and the manner in which it belongs to me and to those I love (those living and dead; those whose time remains and those whose time is lost) suffuses the world; to say we live in a temporal world is to claim that we live in a world that is imbued with our subjectivity. I don’t merely navigate the world, I populate it with forms of significance. I call on it to speak—not just its truth, but mine.

And yet a nagging concern remains—and my readers will have to remember that I’m among the target audience for this book, a non-specialist but interested reader (so any errors here may easily derive from my lack of knowledge—but, of course, this is a book meant for people with my relative lack). I can accept and welcome most of the insights laid out in Rovelli’s book (and to some extent in this review). I can comprehend and acknowledge the fact that time is relative, local, and discontinuous (although I guess the last one is not a fact but a hypothesis). I still cannot wrap my mind around the idea that it only moves from the past to the future because of our perspective on it. I can follow the brilliant notion that entropy is a relative term and that we see things moving from order to disorder when they are more appropriately understood as simply moving from one particular ordering to another. But since we cannot recover those past orders (thus reversing time), I don’t see how Rovelli can claim that time merely is our emotion with respect to it. Indeed, Rovelli anticipates this complaint but anticipation is not answering and dismissing it in the manner that he does is, for me, the most frustrating and disappointing aspect of a book that I thoroughly enjoyed.

Rovelli ends the book with a brief meditation on death. He insists he personally looks toward death with equanimity and contends that the human fear of death is an evolutionary error—we are designed to flee from terror and to predict the future based on our awareness of the world. Hence, we recognize the inevitability of our demise and it frightens some of us through an uncomfortable conflation of reason and emotion. Rovelli closes with a paean to the fairness of death and its relation to time (or its identity with time). This is perhaps the weakest passage of the book; his lyricism overreaches its grasp and what emerges is a rather confused utterance.

I think our fear of death is far more than an evolutionary mistake or a category error. Moreover, I think it’s far more implicated in Rovelli’s narrative than he acknowledges. If we are entropy-tracking machines then we are deeply concerned with order; we seek perfection through order, which is why we so often wax nostalgic about a lost past where things were simpler (i.e., more ordered) and made greater sense (i.e., more rational, and hence more ordered). Any historian knows there never were any “simpler” times—that’s an abstraction of convenience and a pernicious one at that. One aspect (a vital one) of our conception of ideal order is perfection and “perfection” comes from the Latin word for “complete”. Our fear of death, in this sense, may partly derive from the open-endedness of our existence. No matter how much we strive to “get our house in order”, there will always be work left undone. Our lives end but they are never completed.

Thus, Rovelli’s use of Beethoven’s Missa Solemnis as his final image is a bit misleading. He describes the music of life as fading and then ceasing, implying that this music is open-ended in the manner in which I am describing death. A fade-out on a recording never resolves; we can imagine the music continuing into perpetuity. I get the impression Rovelli has something similar in mind with respect to our existence; the music (and our life) is beautiful and slips away, its beauty grounded upon its evanescence.

But Beethoven’s piece doesn’t just end, it is completed. It has a conclusion that fulfills its content and renders it complete. Our deaths, no matter how beautiful and no matter how “full of days” we may be, cannot do that. There’s always more, a yawning abyss of possibilities that lay in our wake. Our deaths cannot fulfill our lives. This warrants some negative emotion, and for many, that emotion is fear. If we are order-obsessed creatures, as Rovelli contends, insofar as we track our progress through the world by noting the increase of entropy, we also work to counteract it. We might see the world as slipping into disorder but we exert ourselves to provide some stability, some order for ourselves, the ones we love, our community. Our fear of death may derive from our realization of the beautiful futility of the effort (which is not to claim it ought to be disavowed as a project). Our fear of death (however muted it may be) provides the urgency to create, in full realization that our petty creations are never to be completed. It may be part of what is behind Rovelli’s writing of this book, behind our conception of time, behind my wrestling with Rovelli’s ideas.

While time is localized, it is also (as Rovelli recognizes) shared locally. We share our time—our past and future, our hopes and fears, our very presence in all its temporal and spatial repletion—with others. To some extent, that time continues beyond our demise. Perhaps this constitutes a justification of hope. In some small way, our time transcends our existence. These thoughts are my own. They may or may not be worthy of Rovelli’s example.

Rovelli strikes me as a patient and generous thinker. I admire the manner in which he approaches the thoughts of those preceding him, the manner in which he invites the reader into his own thinking, and the manner in which he makes room for more thinking in the space of the reader’s conception. The Order of Time is a little wonder of a book. It provides surprising insights into an increasingly mysterious world, offers warmly humane reflections on our existential condition, and sustains a virtual conversation that will continue long after the reading has ceased.

RATING 7 / 10