I recently listened again to Richard Feynman explaining why the flowing of time is probably an illusion. In modern physics time is just a coordinate, on the same footing as space, and the universe can be described as a four-dimensional object — a spacetime block. In that view, nothing really “flows”. All events simply are, laid out in a 4D structure. What we experience as the passage of time is tied instead to the arrow of entropy: the fact that we move through a sequence of states ordered by increasing disorder, and that memory itself is asymmetric.

In this picture, our lives are not things that come into being and then vanish, but extended trajectories in spacetime — worldlines of atoms, fields, and information. Each of us is a kind of 4D crystal: a fixed structure seen from the outside, but experienced from the inside as becoming. And we are all embedded in a larger 4D crystal, our common universe. Past, present, future and space all existing at the same time, elsewhere or elsewhen.

I found it useful to think of this with a mundane analogy. A vinyl record contains music even when it is not being played. The grooves encode the entire soundtrack in a static way. When we put the needle down, vibrations appear, air moves, and music happens. But nothing new was created at that moment — the structure was already there.

Our existence may be similar. The “track” corresponding to my life exists as a spacetime trajectory whether or not it is being experienced. Consciousness, in this analogy, is not the groove but the playback. The feeling of a present moment, of a self moving through time, is what it feels like for a trajectory to be “read” along the entropy gradient.

There is a further twist we can touch on. Today, old wax cylinders that can no longer be physically played can have their sound reconstructed by scanning the grooves in 3D and letting a computer infer the vibrations that would have occurred. I had experience of this during an edition of the Elba conference on advanced detectors, when my former CDF colleague Carl Haber demonstrated the concept and played out some very old songs long lost in unplayable cylinders.

If we think about that, we realize that the music is not tied to the original needle or even to the original material. It is tied to the structure. That suggests something unsettling but hard to dismiss: the reality of our experience may depend more on organization and information than on any privileged physical instantiation. And there is no fundamental difference between a "real" experience of our worldline or a simulation thereof, produced by a computer!

And at this point I am also tempted to also draw a radical conclusion. I only ever experience my own track. I never hear the music of anyone else’s. So why not conclude, by a sort of Occam’s razor, that only my track is being played?

In truth, I think this step goes too far. What my experience tells me is not that other tracks are silent, but that experience is indexical. Each playback only hears itself. The block universe may contain many potential experiential structures, but experience does not need to be globally synchronized to be real. There is no requirement that all tracks be “playing at once” in any absolute sense: each realized perspective is sufficient unto itself.

The illusion, then, is not just the flow of time. It is also the idea that existence must be continuously enacted everywhere to count as real. A spacetime trajectory can exist without being experienced, just as a record can exist without being played. And experience, when it happens, needs no cosmic audience — only a local process that gives rise to it. 

I find this view both humbling and oddly reassuring. If time does not flow, nothing is truly lost. If experience is local, nothing needs to be central. We are not sparks briefly lit in a void, but patterns in a vast 4D crystal — finite along our own tracks, eternal in the only sense physics seems willing to grant us. 

Going back to the fallacy of trying to apply Occam's razor, while it is silly to conclude that we are alone in the universe, and that only our own track of "self-conscience" is being played out, we must admit the possibility that only some of them are simultaneously played. What this means, I leave it to you - be sure to let me know what are your thoughts on the matter in the comments section if you like!