A common interpretation of Special Relativity—the Block Universe—is often presented as the natural reading of the physics. On that reading, our immediate, living "Now" is treated as a psychological perspective rather than a fundamental feature of reality, while past, present, and an already-written future exist alike as coordinates in a four-dimensional fabric.
But there is an interesting historical crossroads. What if the timing had been different? What if Einstein had lived to see the definitive results of physicist John Stewart Bell’s famous quantum entanglement experiments in the 1960s and 1970s?
It is at least plausible, given Einstein's deepest philosophical convictions, that this new information might have pushed him away from a block-universe reading and back toward something closer to the framework laid down by Hendrik Lorentz: a universe with an absolute preferred rest frame and a genuinely unfolding present moment.
1. The One-Way Speed of Light Trap
In his landmark 1905 paper, Einstein made explicit a point that standard physics textbooks often gloss over: we have never actually measured the one-way speed of light.
The cleanest measurements are round trips: we fire a laser from a clock, bounce it off a mirror at a distant point, and measure the time it takes to return, then divide the total distance by the total time. The deeper point is not that literally every setup is a round trip—people have tried one-way arrangements—but that no such measurement escapes a synchronization convention. To clock a one-way trip you need two separated clocks already set to agree, and any procedure for setting them (including slowly carrying one clock away from the other) quietly builds in an assumption about one-way speed. That is why the one-way value cannot be cornered by cleverer apparatus alone.
Einstein explicitly treated the assumption that light travels at the exact same speed ($c$) on the way out as it does on the way back as a stipulation—a convention adopted to make the coordinate math symmetrical and elegant—not an experimental fact. If light actually travels at different speeds in different directions because an apparatus is moving through a preferred physical reference frame (the Lorentzian view), our current round-trip measurement methods completely mask the difference. We simply cannot measure it any other way with a single clock.
How much genuine freedom this leaves is itself contested, and this page should not pretend otherwise. David Malament argued in 1977 that standard synchronization is in fact uniquely singled out by the causal structure together with an inertial worldline, and the literature has gone back and forth since on how far that result really bites. So the conventionality of simultaneity is a live dispute, not a settled fact—this page takes the conventionalist side of it deliberately, not as something already proven.
2. The Spooky Reality of Quantum Entanglement
Because Einstein insisted that space-time was a local, geometric fabric where the speed of light was an absolute cosmic barrier, he spent the latter half of his life fiercely rejecting the implications of quantum mechanics. He famously mocked quantum correlation as "spooky action at a distance."
Einstein argued that two distant, entangled particles couldn't possibly influence each other instantly. If measuring particle A on one side of the galaxy instantly dictated the state of particle B on the other side, it would mean information was traveling faster than light—defying the local speed limits of his geometric space-time. He died believing that quantum mechanics must be incomplete, and that the universe must be strictly local under the hood.
But in 1964, John Stewart Bell published his revolutionary theorem, providing a mathematical way to test Einstein's assumption. When physicists finally ran the relevant experiments, the results came down heavily against purely local hidden-variable accounts. Quantum entanglement is a hard experimental fact, and the observed correlations put real pressure on any view that tries to keep the world strictly local under the hood.
3. The Information That Changes Everything
Faced with Bell’s results, mainstream physics largely accepted that the world is non-local in a specific, carefully defined sense—while keeping the four-dimensional Block Universe interpretation intact. (Because of the no-signaling theorem, this non-locality does not let anyone send information faster than light, so it is not generally treated as a contradiction with relativity.)
But if Einstein had been handed Bell’s data, his lifelong demand for strict, logical causality might well have pushed him down a different path. He might have concluded that he didn’t need to accept "spooky magic"—only to reconsider his ontology.
Where a preferred frame actually earns its keep is narrower than "it makes entanglement normal." It does not: the Bell correlations stay non-classical in every frame, and a universal Now does not turn them into ordinary signals. The specific payoff is for realist attempts to say what is physically going on beneath the statistics—pilot-wave (Bohmian) and dynamical-collapse models—which need a preferred way to slice spacetime into moments to make their non-local updates relativistically consistent. A universal present supplies exactly that slicing. This is an interpretive advantage for those models, not a measured result.
On this interpretation, c is read not as a brute geometric feature of spacetime itself, but as the speed at which causal influence propagates through the preferred rest frame. It is worth being precise about one thing the older ether picture got wrong: c is not specifically an electromagnetic quantity. Gravitational waves travel at exactly the same speed (as the 2017 neutron-star merger confirmed), which tells us c is the invariant speed of the causal structure as a whole, not just of light. A neo-Lorentzian reading has to treat it that way too. John Bell did not uniquely prove NeoLET, but his theorem added pressure against the idea that reality is exhausted by a strictly local geometric reading.
Standing on the Shoulders of Giants
The core framework of a Neo-Lorentzian Theory of Causal Rest (NeoLET) is not an arbitrary invention. It stands directly on the shoulders of giants like Hendrik Lorentz and Henri Poincaré—the brilliant minds who laid down the foundational mathematical transformations that make relativity work in the first place.
By using the identical mathematics but interpreting the ontology differently, this framework aims for a picture some find more intuitive: a universe with a single unfolding present, in which relativity’s tested predictions still hold and the future is treated as genuinely open, built one moment at a time. Whether that picture is correct is a question of interpretation, not one that current experiments settle.