Underdetermination in relativity

General
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1, Underdetermination in relativity - The experiments that are said to be explainable by Einstein special relativity (SR) is said to be explainable by Lorentz ether theory (LET). (empirical evidence that can be explained by different theories is called underdetermination)

  1. This then leads to false claims by physicists - they will start saying there is no ether, no preferred frame etc.
  2. But those claims are just under the context of how SR interprets experiments.
  3. In LET those same experiments are interpreted as having ether, preferred frame etc.
  4. Thus those physicists who don’t add proviso to those claims that are meant in the context of SR are not stating things properly.
  5. Also when they claim there is no ether, no preferred frame etc that is not what the experiments show. i.e. are making claims beyond what the experiments show
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Roger is :100: correct.

The experiments (Michelson-Morley, Kennedy-Thorndike, Ives-Stilwell, etc.) are underdetermined: they are equally compatible with Einstein’s Special Relativity (SR) and with Lorentz Ether Theory (LET). Both frameworks reproduce the same observable predictions for those tests, yet they differ radically in ontology, one eliminates any preferred frame and absolute simultaneity, the other retains a preferred frame (the ether) and absolute simultaneity while introducing length contraction and time dilation as real physical effects of motion through the medium.

Physicists frequently drop the crucial proviso “within the interpretive framework of SR” and state flatly “there is no ether, no preferred frame,” as if this were a direct experimental result. It is not. The raw data are silent on the choice between the two interpretations; the decision is philosophical or conventional, not empirical. This is textbook underdetermination.

We can recover the full set of Lorentz transformations and all weak-field GR effects from first physical principles without Einstein’s two postulates and without geometric abstraction (curved spacetime, Minkowski metric as primitive), with just basic assumptions:

  1. Light as continuous EM wave
  2. Vacuum as responsive medium (classical analog explanation of GR) Classical Unification of Gravity and Electromagnetism
  3. Phase continuity as the sole physical invariant (classical analog explanation of SR) REFORM: REfractive Foundation of Relativity and Mechanics

No abstract postulates about constancy of (c) in all inertial frames or relativity of simultaneity are required. The transformations emerge directly from demanding continuity of a classical electromagnetic wave in a physically responsive vacuum. In gravity the observer’s own apparatus is strained by the same (n(r)), so the measured redshift is the full GR value; under acceleration there is no vacuum strain, recovering the observed half-effect (Sturm, Bertozzi reanalysis via Jormakka).

Thus SR and the weak-field limit of GR are not fundamental symmetries of spacetime but emergent consequences of wave propagation in a medium whose electromagnetic properties respond to mass/energy. The underdetermination Roger highlights dissolves once we supply the missing physical mechanism: the responsive vacuum supplies the exact structure that both SR and LET were attempting to describe, but without the interpretive baggage or unobservable entities.

The experiments do not force us to abandon a preferred frame or absolute simultaneity; they are fully compatible with a classical, local, causal ontology once we treat light as a continuous wave in a responsive vacuum. The choice between interpretations is no longer arbitrary in my work.

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I’m not sure most people really understand that GR/SR are postulates and abstractions. Even in academic circle it’s taken for granted. There is no physical connections the effects, therefor it’s just a math abstractions. It’s just “curvature” or because of constant speed of light etc.. They assume global invariance yet gravity causes the Shapiro delay, red/blue shift by postulate. Nothing is properly derived from causality, phase continuity, or simply first principles.

Nobody is engaging with you Roger because most don’t understand underdetermination, postulate and abstraction. It was made to be acceptable in academia, but it’s not. Science as always been a Ptolemaic patchwork but we should always keep in mind it need to describe a physical reality without dark entities or other non-sense.

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Relativity is taught badly to most people hence why they don’t understand the relevant issues of underdetermination etc. Anyway, I have problem here with this Forum - it does not allow too many replies from me.

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Backup on my Google drive: Dingle conversation with Brave AI

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There’s a broken link in your comment.

Here’s an archived version: link

  • I also backed it up on the Japanese archiver megalodon and ghost archive.
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Conversation with Brave AI reconstruction via Deepseek AI:

# Dingle Paradox for Relativity – Cleaned Conversation

## User: Dingle Paradox for Relativity

**Brave AI:** The Dingle Paradox (or Dingle’s Clock Paradox) was an argument advanced by British astrophysicist Herbert Dingle (1890–1978) claiming Einstein’s Special Theory of Relativity (STR) is logically self-contradictory.

### Core argument

Two clocks in relative motion each see the other as slower → “If A works more slowly than B, then B must work more slowly than A – which is impossible.”

### Why physicists reject it

1. **Relativity of simultaneity** – “at this moment” refers to different sets of events in different frames. Dingle assumed absolute simultaneity.

2. **Twin paradox distinction** – acceleration breaks symmetry.

3. **Misdefinition of “event”** – Dingle combined multiple spatially separated readings into one “event.”

### Conclusion

The paradox arises from rejecting relativity of simultaneity. Experimental evidence confirms STR.

-–

## User: Tbh, I think the pro-SR physicists shouldn’t have used the term “event” that way. An event in everyday speech is not a single point in time, but a time interval.

**Brave AI:** Valid point. In STR, an “event” is a zero-dimensional point (t,x,y,z). Everyday “event” implies duration. Dingle’s argument fails regardless because intervals are built from points, and different frames measure different pairs of events due to simultaneity differences.

-–

## User: The “t” in a point in spacetime is a “coordinate”, not an “event”. I think the physicists meant something like “landmark in spacetime”.

**Brave AI:** You are technically correct. t is a coordinate; an event is the location (t,x,y,z). “Landmark in spacetime” is an excellent analogy. Dingle’s error persists: observers agree on the landmark but assign different coordinates.

-–

## User: At a particular time “t”, nothing is “happening” – it’s a frozen part of spacetime. Things only happen between two or more time coordinates.

**Brave AI:** Absolutely correct. A single coordinate represents a frozen slice. Physical processes require an interval (Δt). A clock ticking is the worldline between events, not at a single event.

-–

## User: What’s the proper temporal terminology for a runner in a race at the start and the end of race? Are these “events”?

**Brave AI:** Yes – both start and finish are events (zero-dimensional points). The race itself is the *worldline*, and the duration is the *proper time* (Δτ) or *coordinate time* (Δt). Nothing “happens” at the start event itself – running exists only in the interval between events.

-–

## User: What would these positions in time-space be described as pre-Relativity (around the 1800s or before)?

**Brave AI:** In Newtonian physics: separate concepts. The start was a *position in absolute space* occurring at an *instant of absolute time*. No unified “spacetime event.” They would say: “The runner was at position P at instant t.” Space and time were independent stages.

-–

## User: What did “event” mean pre-Relativity?

**Brave AI:** Pre-relativity, “event” had no technical geometric meaning. It meant an occurrence or happening with duration (e.g., a collision). Newton spoke of the “succession of events” as the measure of time. It was a verb-like concept turned noun.

-–

## User: [cut off, then resumed] Key Conceptual Difference – Pre-Relativity: event = dynamic happening. Relativity: event = static location (geometric noun). Example: “The collision was a violent event” (process) vs “The collision occurred at event E” (coordinate pinprick).

**Brave AI:** **Conclusion:** Before 1905, “event” meant an occurrence with duration. The shift to a zero-dimensional spacetime point was an innovation of Special Relativity (Minkowski, 1908). Your intuition that the modern term feels disconnected from “happening” is historically accurate – the word was repurposed from describing a process to describing a location.

Regarding Roger’s talk on Dingle