I think the flow of time is not part of the fundamental structure of reality,” theoretical physicist Carlo Rovelli tells me. He is currently working on a theory of quantum gravity in which the variable of time plays no part. And throughout our conversation, I’m trying to get my mind around the idea that even though the universe is made up of “events,” as Carlo explains, a single interval between two events can have different values. There is no central clock, its hands ticking a steady beat for the universe to march along to, moving in one direction from the past into the future.
The prospect that our experience of time may not correspond to an underlying reality has fascinated me for as long as I can remember, as the idea connects two of the most intriguing topics—time and consciousness. Inspired by my recent conversations with Carlo and others in the production of my podcast documentary series, I’ve been thinking more about where the two phenomena overlap.
The more closely we observe the present moment, the more amorphous it becomes. It vanishes as we reach out to touch it, transforming into the next moment, and the next … When we look out at the ocean, we naturally perceive the waves while understanding (both intellectually and intuitively) that there is no real “thing” that is a wave. The concept is useful shorthand for a dynamic phenomenon that occurs in nature. So too with the human brain, which is an ever-changing symphony of electrical firing among billions of neurons.
Contrary to our everyday intuition, there isn’t an entity persisting through time in the form of a static “self.” All our conscious experiences are being generated anew by dynamic neuronal activity. Like an ocean wave, your “self” is an endlessly fluctuating process. Memories trail along from the past, and those memories impact your experience in this moment, but each moment of your experience still depends on the exact state of your brain at that particular point in time.
We’re always residing in the here and now, yet each moment is instantaneously swept away by a ghostly breeze. There it goes. How long did it last? The more focused our attention is on our experience through time, the faster the moments rush by. A raging river. Yet, a vast, peaceful stillness rides along the never-ending stream. We are eternally racing toward the future—yet not moving at all. There’s no traveling forward when you are the river.
I often wonder if time is our small keyhole into a deeper reality—just a glimpse of the vast structure of the universe. Could time be an illusion of sorts? Through the various attempts to understand the implications of quantum mechanics, many physicists have become convinced that spacetime is emergent—that both space and time are manifestations of a more fundamental reality. In a 2014 lecture at the Perimeter Institute for Theoretical Physics, the prominent theorist Nima Arkani-Hamed declared it plainly: “Almost all of us very strongly believe that spacetime really doesn’t exist.”
Whatever is true about the fundamental reality, the space we seem to be moving through clearly represents something about the world. However, as we’ve come to understand, the way our brains process incoming information often creates a distorted impression of what’s actually “out there.”
In a 2016 Nautilus essay, “Let’s Rethink Space,” science journalist George Musser uses a musical analogy to show how what appears to us to be spatial distance might in fact be a difference in energy:
Sounds of long and short wavelengths are oblivious to each other; if you sound a deep bass note and a high treble pitch simultaneously, each ripples through the room as though it were the only sound in the world … These waves overlap in the three dimensions of space through which they propagate, yet they’re independent of each other, as if they were located in different places. In a sense, you can think of the sound waves as residing 14 centimeters apart within a fourth spatial dimension.
But harder still is the project of constructing an analogy that helps us wrap our minds around the possible misrepresentation of time in our experience. In my efforts to understand what it would mean for the flow of time to be an illusion, the closest visualization I’ve been able to create is that of a web of nodes in which we experience only one node at a time. At each locus, all the other nodes become inaccessible to us, as if a spotlight were continually traveling across this “web of time,” inch by inch, painting our reality. If you were to experience a structure on this web —such as node a, node a, node f; node a, node a, node f—you might interpret the experience as “two node a’s cause a node f” when, in fact, the whole web of nodes already exists in its entirety. The implicit causality would not apply at a deeper level. Causality through time would still illuminate “connections,” it’s just that the underlying reality of these connections would reveal a structure vastly different from the one we intuit—that is, a universe with a flow of time, where the past is set in stone, the future is undetermined, and the present is the only true “reality.”
In his most recent book, Einstein’s Unfinished Revolution, physicist Lee Smolin describes the conclusions that his colleague Julian Barbour has reached about the nature of time:
Barbour insists that the passage of time is an illusion and that reality consists of nothing but a vast pile of moments, each a configuration of the whole universe. You now are experiencing a moment. Now you are experiencing a different moment. According to Barbour, both moments exist eternally and timelessly, in the pile of moments. Reality is nothing but this frozen collection of moments outside time … The moments all coexist, and each is a configuration of the whole universe.
Smolin himself holds a different belief, concluding that whereas space is not fundamental, time is still part of the fundamental story. But Smolin’s work, too, reflects the degree to which the true nature of reality is at odds with our day-to-day intuitions. In his book, he depicts the universe this way:
Your view of the world is like a film projected on a two-dimensional sphere, which we call the sky … Hypothesize that all that the universe consists of is these skies—each one the view of some event. Rather than construct the views from the causal relations, reverse things and derive the causal relations and everything else from the views.
In these musings I’m often left wondering to what degree our conscious experience of the flow of time is responsible for our confusion about it. Is it possible that experiencing a deeper structure of the universe is what we’re calling time? Are time and consciousness perhaps two sides of the same coin?
Whatever turns out to be true about the nature of reality, in every moment of our lives we have firsthand knowledge of a simple truth: Circumstances have come together to create an experience of witnessing the universe unfold from within, however limited our perspective. How and why may always remain mysteries—perhaps by definition, as Smolin’s skies suggest—but in the meantime, we can revel in the wondrous view.
Annaka Harris is the New York Times bestselling author of Conscious: A Brief Guide to the Fundamental Mystery of the Mind. She is an editor and consultant for science writers, specializing in neuroscience and physics, and her work has appeared in The New York Times. Annaka is the author of the children’s book I Wonder, a collaborator on the Mindful Games Activity Cards, by Susan Kaiser Greenland, and a volunteer meditation teacher for the Inner Kids organization.
Lead photo: Replica Of Nature / Shutterstock