Clash of Geniuses: Debating Science’s Unsettled Frontiers

Einstein’s theory of relativity proved that two observers, just by moving at different speeds, will fundamentally disagree on what “now” even means. Which shatters the whole idea of a single, universal clock ticking for everyone. Last week on the show, we debated whether cancer is a single disease or a chaotic ecosystem. Today, we’re pulling the camera back even further—to ask if time itself is real, or just a stubborn illusion. I think it’s real. Let’s start there. I'll take the position that time is fundamental. It's a dimension of the universe, like length or width. It’s the river in which reality flows. Without it, you can't have cause and effect. You can't have anything.

I hear you, and that’s the intuitive view. It’s what we experience every day. But some of the deepest theories in physics suggest that time isn't fundamental at all. It’s emergent. It’s a secondary effect, like the wetness of water. Okay, but a single water molecule isn't "wet." You need a lot of them interacting for wetness to emerge. What are the "molecules" of time? Information. Think of it this way: every single interaction in the universe—every particle collision, every photon absorbed—imprints a tiny, irreversible piece of information. That sequence of imprints creates an order. And what we call the "arrow of time" is just us perceiving that accumulation of information.

It doesn't flow; it’s built, moment by moment. So the universe is just a cosmic hard drive, and time is the file system? I find that idea, as physicist Laurent Freidel put it, "profoundly disturbing." It takes the most basic thing we know and says it's a ghost in the machine. It's only disturbing if you're attached to the old model. But that old model is broken. It's why we can't unify general relativity and quantum mechanics. One treats time as elastic and dynamic—spacetime—while the other treats it as a fixed, absolute background ruler. They can't both be right. That's fair, except some physicists are finding ways to fix that without throwing time out completely. At the Perimeter Institute, they're building spacetime from the bottom up using tiny geometric pieces they call "embadons." In their model, quantum time is still a fundamental property.

So you don't have to kill time to save physics. But what are they really doing? They're still describing evolution with respect to something. The emergent camp just says that "something" is more fundamental than what our clocks measure. Your clock doesn't measure "time." It measures a consistent, repeating physical process—a swinging pendulum, a vibrating quartz crystal. It's measuring events. Alright, I'll give you that one. A clock measures events, not some abstract metaphysical flow. But those events happen in sequence. That sequence has to exist as a dimension for them to happen in. Or the sequence is the dimension. The information creates the order. It's not placed into a pre-existing order.

We think of spacetime as a passive stage, but what if it's an active participant? What if it's the medium that's actually recording all this information, and that very process of recording is what we experience as time passing? Okay, but consider this—if time is just an emergent illusion from information processing, why does it only go one way? Why can't we remember the future? Because the information imprints are irreversible. You can't unscramble an egg. You can't erase the information that was written. The "past" is just the information that's already been recorded. The "future" is what hasn't been written yet. There's a physical asymmetry there. So we’re back to a universe that feels… computed.

Not lived. I think the simpler explanation is the one Einstein gave us: time is woven together with space. It’s a real, physical fabric. It can be stretched by gravity, slowed by speed, but it’s there. It’s a dimension. And I think that was a revolutionary step, but not the final one. Saying time is just a dimension is like a character in a movie saying the film reel is the ultimate reality. They can't see the projector, the light, the screen that are all required for their world to even exist. Emergent time isn't saying your experience is fake. It's saying it's a projection of something deeper. And that’s where we land, I think. The real debate isn't whether our experience of time is real—it obviously is.

We live our lives by it. The question is whether time is the stage itself, or just the shadow play happening on it. Exactly. Is time a fundamental property of the universe, or is it a property of the information within the universe? And that forces us to ask what's more fundamental: the container or the thing contained.