What Does "Now" Really Mean? Rethinking Our Place in Time

This blog post was generated based on my discussion on with Gemini chat model.

Here is NoteLM generated podcast.

We all feel it. That immediate sense of now. The moment that separates the fixed past from the open future. It seems simple, right? "Now" is just... now. But delve into modern physics, especially Einstein's Relativity, and you hit a wall. Physicists often talk about time being relative, about observers disagreeing on what's happening "at the same time" across the universe (the famous "Relativity of Simultaneity"). This has led many to suggest our intuitive sense of a single, universal "Now" might be an illusion, pushing ideas like the "Block Universe" where past, present, and future are all equally real, like places on a map.

Does that feel right to you? Does the idea that Julius Caesar crossing the Rubicon is just as "real" right now as you reading this sentence seem plausible? Or does it feel, as it does to me, like an "absurd notion"?

I believe the confusion stems from letting a specific (though successful) physical theory, Special Relativity (SR), dictate the meaning of a fundamental concept like "Now." SR is brilliant at describing how things move and interact, especially at high speeds, and it correctly incorporates the universal speed limit – the speed of light (c). But does it define reality itself?

What if "Now" is Simpler (and More Fundamental)?

Let's go back to basics. Ask anyone on the street, "What is your present?" They'll likely point to what's happening right here, right now – the latest thing in their immediate experience. Let's call that your local "Latest Event," L_you.

Now ask them about someone far away, say, on Mars. What is their present? The intuitive answer isn't some complicated calculation involving reference frames. It's simply: "Whatever the latest thing happening to them is." Let's call that L_Mars.

What if that's the real definition? What if the true, objective, universal "Now" is simply the grand collection of all these local "Latest Events" happening everywhere across space? Let's call this collection Set G.

G = { The Latest Event happening locally at every single point in the universe }

Why This Makes Sense:

1. It's Objective & Abstract: This definition depends only on what's happening at each place, independently. It doesn't rely on observers, their motion, or how they might see each other.

2. It Matches Intuition: It aligns perfectly with our deep-seated feeling about the present, including our understanding (think thunder and lightning!) that when something happens is different from when we find out about it. Event occurrence (part of G) is separate from perception/signal delay.

3. It Supports Presentism: This definition naturally leads to Presentism – the idea that only the present (Set G) truly exists. The past is gone, the future isn't here yet. Only the "latest events" everywhere are. This avoids the seemingly absurd idea of the past and future co-existing with us.

4. It's Frame-Independent: Because G is defined locally everywhere without forcing the idea of "simultaneity" onto it, it doesn't depend on who's looking or how fast they're moving.

Where Does Relativity Fit In?

SR is a powerful tool describing how things relate and interact within the reality defined by G, especially given the finite speed of light c. Because c is finite, relating different points in space and time does lead to the effects SR describes, like relative simultaneity in terms of coordinate systems and measurements.

But, I argue, SR describes a secondary layer – the layer of relations and signal travel – built upon the fundamental layer of existence, which is G. SR’s concepts are needed because c is finite, but G’s existence doesn’t depend on c. Think about it: if c were infinite, SR’s weird effects would disappear, leaving absolute time and absolute simultaneity – and G would perfectly represent that absolute Now. This suggests G is the underlying reality, revealed when SR's finite-c complications vanish.

Challenging the Alternatives:

From this viewpoint, the Block Universe or Growing Block ideas aren't descriptions of reality but seem like philosophical contortions ("illusions") created by taking SR's secondary, relational structure and mistaking it for the fundamental ontology. They arise from the problem SR creates for simultaneity, but our G-based Now doesn't require simultaneity in the first place!

Time to Rethink?

Perhaps scientific thought, deeply invested in the successful framework of SR, has inadvertently let SR redefine "Now" and "existence," obscuring a simpler, more fundamental, objective reality captured by G. Maybe the "plain language" understanding, in this rare case, holds the key.

What do you think? Does defining "Now" as the collection of local latest events make more sense? Is Presentism, based on this definition, the most rational view of time? Let's discuss!