“That which hath been is now; and that which is to be hath already been.” Ecclesiastes 3:15:

One of my current poetry projects involves Carlo Rovelli’s work on loop quantum gravity; I am using his metaphors – such as chain mail and snails – to inspire poems. Many of the physical concepts and relationships Rovelli describes are counterintuitive, so metaphors are useful in understanding them. One of the most difficult concepts to grasp is Rovelli’s claim that there is no such variable in physics as time. In this musing, I explain what he means and then suggest that lack of time is a good thing for poets.

Wait, you say. No time? How can that be? Our clocks and watches measure time. We can tell yesterday from today from tomorrow. True. But Rovelli explains that time is a construct created by humans, not a basic physical property in the world. (For an overview of Rovelli’s argument, you can watch this 50-minute talk: https://www.youtube.com/watch?v=NrjFE_Rd2OQ)

Rovelli and his colleagues are not the first to explore the meaning of time. 

“For the Greeks, time is the demarcation of events. Plato understands time as an effect of celestial mechanics in Timaeus, while Aristotle in the Physics thinks of time as an attribute of movement. To Kohelet, though, time itself is an enigma; as with [Saint] Augustine, it is the moment itself that remains imperceptible.” (David Goldman, “The Divine Music of Mathematics,” First Things, April 2012, https://www.firstthings.com/article/2012/04/the-divine-music-of-mathematics)

Let’s start by examining some of the quirks we know about time. We already know about Einstein’s relativity theory: A man is on a commuter train, walking to the dining car to get a cup of coffee. Relative to the train, he is walking at about three miles per hour. But relative to earth’s surface, he’s hurtling along at 60 miles per hour. So we understand that a physical property can be relative to something in its environment.

In the same way, time can vary with its proximity to a large mass. Suppose we could synchronize two clocks (that is, set them to show exactly the same time) and then carry one up a mountain. The times on the synchronized clocks will start to differ, because the clock on the mountain is farther from the center of the earth – the center of mass. The higher clock will run faster than the lower one. And if we could somehow move the lower clock to somewhere near the center of the earth, it would run very slowly indeed. So time is more elastic than we think it is; it can depend on the clock’s location.

The time difference also depends on how the clocks move. If, holding a clock, I move very fast – such as near the speed of light --- my clock will show that less time has passed than if I stand still. Moreover, it’s impossible to know when two clocks have the same time. Suppose you hold one clock while I hold the other. When I look at your clock, I’m really looking at light reflected from your clock, and that light has to travel a small distance to get to me. So I’m not really seeing your clock right now; I’m seeing your clock in the past. In the same way, it’s impossible to know what is happening “now” in a far part of the universe. The notion of “now” is a local concept; it makes no sense for the entire universe. We might be able to perceive very small differences, such as a tenth of a second, and we can agree to call what happened in that tenth of a second our “now.” But beyond such informal, local agreements, we cannot assign a general time that connects all objects. Objects can send signals to each other, but because of the distance between them, we cannot know if two things are happening at the same time.

Well, now you’re scratching your head and trying to think of counterexamples. What about the difference between past and future? We remember what we did yesterday, but we can’t be sure what we will be doing tomorrow. We can remember ourselves as children, but we don’t know ourselves in the future. Nevertheless, we assume that the physical laws that governed the past will also govern our activities in the future. 

Then what differentiates the past from the future? To answer that question, think about watching a film of a pendulum swinging. Eventually, the pendulum swings more slowly and then stops. If I show that film backwards, what you’re seeing is not realistic: a pendulum spontaneously starting to swing. Why? Because in real life, friction slows down the pendulum. Friction’s heat causes molecules to move faster, spreading their energy to the molecules around them. In that process, order becomes disorder. And that’s the essential difference: The past is ordered. The future is not.

Still, there is a relationship between past and future. To understand it, think of the world not as a set of entities but rather as containing events and processes. Entities dissolve. Events and processes evolve; they disaggregate and form. In this formulation, absence of time doesn’t mean the world is frozen. Quite the opposite: It means events are constantly happening in the world. Physicists try to write equations describing how different events happen with respect to one another.

To describe the events in an equation, we first decide how close we can get to them; we make observations about events from some vantage point. But we cannot see the world in extreme close-up, in very small bits, in its essential elements. We see just aggregated bits, much as the Voyager spacecraft captured a photograph of Earth in 1990 as a Pale Blue Dot. Similarly, when we look at a drop of sea water, we don’t see the millions of water molecules that comprise it. We don’t see the plant and animal life suspended in the droplet, or the salt dissolved in the water. We don’t see how one droplet is the same as or different from another droplet. We see a world that is blurred and approximate, not an exact, detailed look at the very different parts that make up the whole. 

It is through this fog that we see space and time. But due to this blur, we lose control of reality. Energy disappears into heat. We don’t see molecules moving or heat being generated. Indeed, heat is part of what blurs objects or events. So we see the world only with our own perspective. We look up and see clouds and stars moving overhead, see the sky turning, the stars twinkling, only by observing relationships among us, the planet we stand on, and how we and it move through the universe. Our understanding is necessarily relational. Time is a concept we have invented to help us describe how we interact with the world. It is not a characteristic of the world itself. And we differentiate past from future by interacting with the world.

We perform the differentiation not by thinking of time as a clock but rather by thinking of time as our memories of the past. For instance, consider how we listen to music. At a given point, we hear just one note of a melody. Having heard the same or similar notes, our mind retains both the melodies and the feelings we associate with the music. And we often anticipate what notes are coming next; our brain tries to predict the notes in the future by using our memories of the past. Thus, for us, time is the threshold between memory and expectation, between antecedent and anticipation.

The idea of the future as expectation is not new. It was described by St. Augustine in his Confessions:

“It is in you, my mind, that I measure times,” he concludes. “…the mind expects, it considers, it remembers; so that which it expects, through that which it considers, passes into that which it remembers. … It is not then future time that is long, for as yet it is not: But a long future, is ‘a long expectation of the future,’ nor is it time past, which now is not, that is long; but a long past is ‘a long memory of the past.’” (quoted in David Goldman, “Sacred Music, Sacred Time,” First Things, November 2009, https://www.firstthings.com/article/2009/11/sacred-music-sacred-time_

Marcel Proust’s novel, In Search of Lost Time, was conceived in a similar way, as an extended description of a man’s life not in terms of what happened but rather of what he remembers. The book’s events come from the author’s mind, not from the physics of the world. Gabriel Garcí­a Márquez seems to be aware of the same notion of time as memory:

“They were people whose lives were slow, who did not see themselves growing old, or falling sick, or dying, but who disappeared little by little in their own time, turning into memories, mists from other days, until they were absorbed into oblivion.” (Love in the Time of Cholera)

This personalization of what seems like a universal construct happens in other aspects of our daily lives. For instance, we perceive color in a similarly personal way, describing the world in terms of three colors: red, yellow and blue. Not every animal – or even every human – can see those colors, or see them in the same ways you can see them. The colors we use come not from the real world but from our perceptions of that world and the way our brains interpret the world.

Thus, we are not just our physical selves. We are narrations of ourselves based on our memories of ourselves. We have invented time as a notion to impose order on the past (our memories) and the future (our anticipation of events based on our memories of the past). We are in time, but we also use time to remind us of our impermanence – to remind us emotionally of what we are always losing. The sense of flowing that we embed in the order does not appear anywhere in physics. But it is still essential to our understanding of ourselves. 

We perform the differentiation not by thinking of time as a clock but rather by thinking of time as our memories of the past. For instance, consider how we listen to music. At a given point, we hear just one note of a melody. Having heard the same or similar notes, our mind retains both the melodies and the feelings we associate with the music. And we often anticipate what notes are coming next; our brain tries to predict the notes in the future by using our memories of the past. Thus, for us, time is the threshold between memory and expectation, between antecedent and anticipation.

The idea of the future as expectation is not new. It was described by St. Augustine in his Confessions:

“It is in you, my mind, that I measure times,” he concludes. “…the mind expects, it considers, it remembers; so that which it expects, through that which it considers, passes into that which it remembers. … It is not then future time that is long, for as yet it is not: But a long future, is ‘a long expectation of the future,’ nor is it time past, which now is not, that is long; but a long past is ‘a long memory of the past.’” (quoted in David Goldman, “Sacred Music, Sacred Time,” First Things, November 2009, https://www.firstthings.com/article/2009/11/sacred-music-sacred-time_

As poets, we can use this fluidity of time to free us in writing across the boundary of “now.” We can easily move from past to present to future and back again as we examine a concept or feeling. We can capture that sense of anticipation, harken back to emotions that erupt or memories that sharpen. The fog through which we view space and time becomes a vehicle for adding texture and music to our words. Here, Shelley uses it to evoke time as a visual image: shadow.

"Each day a shadow onward cast
Which made us wish it yet might last—
That Time long past." Percy Bysshe Shelley, Time Long Past

Dunbar instead uses aural imagery: the ticking of a clock.

“I had not known before
    Forever was so long a word.
The slow stroke of the clock of time
    I had not heard.” Paul Laurence Dunbar, Forever

And Hardy addresses how time reminds us that we lose something of ourselves as we live our lives:

“But Time, to make me grieve,
Part steals, lets part abide;
And shakes this fragile frame at eve
With throbbings of noontide.” Thomas Hardy, I Look Into My Glass

Sexton’s poem puts time in the context of the sun’s revolution around the earth. She tells us that we try not naming time, not counting seasons, not marking the boundary from one day to the next. But we cannot put off the end of memories.

“There is no word for time.
Today we will
not think to number another summer
or watch its white bird into the ground
Today, all cars,
all fathers, all mothers, all
children and lovers will
have to forget 
about that thing in the sky,
going around
like a persistent rumour 
that will get us yet.” Anne Sexton, The Road Back

T. S. Eliot’s Four Quartets open with a poem called Burnt Norton. In it, the poet explores life’s transience as he sits at the boundary between past and future. Almost a riff on the writings of St. Augustine, Eliot’s poem begins with repeated reminders of experiences missed, opportunities refused, and the possibility of second chances:

“Time present and time past
Are both perhaps present in time future,
And time future contained in time past.
If all time is eternally present
All time is unredeemable.
What might have been is an abstraction
Remaining a perpetual possibility
Only in a world of speculation.
What might have been and what has been
Point to one end, which is always present.
Footfalls echo in the memory
Down the passage which we did not take
Towards the door we never opened
Into the rose-garden.

…

Time past and time future
What might have been and what has been
Point to one end, which is always present.” TS Eliot, Four Quartets

These poems show us that Rovelli’s explication of time from a physics perspective can free us to see our very individual perceptions of time as enablers. Even with reminders of time (the shadows, the sounds, the shaking), we humans have agency. We can interpret, look ahead, look back, and make choices – choices that we may decide to change over time.  

Tamiko Beyer’s poem, Last Days, from her book of the same title (Alice James Books, 2021), uses this freedom from time to weave her thoughts back and forth, from present to past to future. The poem uses an “ancestors’ chorus” as the voice of the past. Early in the poem, she declares:

“I am on the cusp of change, and the curve is shifting fast.

It as an experience and then it was a memory. And then a system of belief, a way to navigate the dissolving world.

I wanted to become more salt wind, less reflection. To become quiet enough to hear the ancestors.”

The ancestors suggest that we rely on and trust our memories:

“Soon you will need to reach
all of us in this river of time
with the truest sentences
you can weave.”

They go on to say,

“Light breaks the glass 
separating you 
from the present.”

Beyer weaves back and forth in the poem, crossing the boundary from memories of the past – hers and the ancestors’ – to observations about a likely future, for her, for the people around her, and for humanity. Embodying the fluidity of time, she declares, “Patience is in the living. Time opens out to you.” She uses past, present and future tense in ways that override the boundary of “now” which, near the end of the poem, she depicts as a sheet of glass separating past from future:

“The present was a sheet of glass suspended in midair.
… we grew up learning how to read the signs … in the sound of breaking glass.
We knew it was long past time.”

Thus, breaking the glass – breaking through from the past to the future – enables the future. Rovelli tells us that our future is colored by our understanding of the past. These poems remind us that humans can act, can push back against change, can instigate change – regardless of or in reaction to the past.