[Colin2B]

or you are populating the universe with clocks at rest relative to the spaceship and referring to those. In the latter case, we said not to introduce anything more and just talk about the spaceship.

you said that, not me, not @Halc.
Coordinate systems and references are for essential understanding measurements, be those coordinates latitude/longitude etc, so it is reasonable to introduce them.

Alice has no way of knowing which situation is the true situation - as per the Galilean Principle of Relativity.

OK you raise Galilean relativity, let's update his famous thought experiment.
We are on board a modern warship. Deep in the bowels of the ship, with no direct outside view is the fire control centre. The officer in charge has a radar screen, he and the ship are at the centre, distance lines are set out on the screen which correspond to actual distances outside. This is not reification, as no one believes there are actual lines on the sea anymore than Alice believes there are real lines outside her ship. The Officer can measure the relative positions of other ships in the vicinity and make predictions about thier future positions. All this without knowing any absolute position or velocity of his own ship, and assuming only that he is at rest relative to himself - not a meaningless tautology, but an important reference point. As @Halc says we need to reiterate this as if you don't recognise the importance of 'at rest relative to a reference frame' then we have to find a concrete anchor.
By the way, I would also answer “don't know” to @Halc question "what is the distance to my elbow?", bcause there is insuficient information to form an answer.

Bob's bodycam footage provides observational evidence to the contrary.

No it doesn't, it only shows movement relative to Bob's ship.

The point is that there is an alternative interpretation of Relativity which doesn't involve the Relativity of Simultaneity. This just further demonstrates the point that the Einsteinian interpretation makes the assumption of Simultaneity in "the stationary system"

If your intention was to discuss LET or Poincaré-Lorentz, it would have been better to start there rather than this route which has made things difficult for yourself.
I have a great deal of respect for Poincaré and there is no doubt that he almost developed the theory of relativity. In 1905 he said “It seems that this impossibility to disclose experimentally the absolute motion of the earth is a general law of nature ; we are led naturally to admit this law, which we shall call the Postulate of Relativity, and to admit it unrestrictedly”, if he had only taken the step of fully accepting the implications of this we would now be referring to Poincaré’s theory of relativity.

[the_roosh (OP)]

Einstein talked about A to B equaling B to A, not E to A equaling E to B.  So this statement has zero to do with your chosen Einstein quote.

Do you genuinely not see how it's the exact same thing? If you can't grasp this point, there is little hope that the rest will be understood:

It might dawn on you if we label the emitter as A and the clock on the left as B1 and the clock on the right as B2.

Can you see that what we effectively have, is 3 examples of Einstein's clock synchronization convention in the one Synchronisation set-up?

If you can't then I'll break it down. But until this - most basic of points - is understood, the rest cannot be understood. Because this is the assumption that is being referred to.

[the_roosh (OP)]

Coordinate systems and references are for essential understanding measurements, be those coordinates latitude/longitude etc, so it is reasonable to introduce them.


OK you raise Galilean relativity, let's update his famous thought experiment.
We are on board a modern warship. Deep in the bowels of the ship, with no direct outside view is the fire control centre. The officer in charge has a radar screen, he and the ship are at the centre, distance lines are set out on the screen which correspond to actual distances outside. This is not reification, as no one believes there are actual lines on the sea anymore than Alice believes there are real lines outside her ship. The Officer can measure the relative positions of other ships in the vicinity and make predictions about thier future positions. All this without knowing any absolute position or velocity of his own ship, and assuming only that he is at rest relative to himself - not a meaningless tautology, but an important reference point. As @Halc says we need to reiterate this as if you don't recognise the importance of 'at rest relative to a reference frame' then we have to find a concrete anchor.

The ship analogy and measuring relative distances is fine because at the relative velocities involved, relativistic effectss will be negligible.

I said that the idea that an observer can be at rest "relative to themselves" is a meaningless tautology. That is the "soft" interpretation. It can actually be taken as a misapplication of the idea of relatioanalism, which requires relating one object to another.

A further issue for our officer arises when he tries to synchronise his clocks. As you said, he has no way of determining whether or not he is in motion. His reference frame being at rest "relative to itself" doesn't give him any information about how his reference frame is in motion relative to the light signals he uses to synchronise his clocks. Therefore, he cannot make any assumptions about the distance each signal travels in the synchronisation procedure - well, he can, but he has no way of determining if it is correct.

I will try to outline below how the thought experiment can be used as a test of that assumption.

By the way, I would also answer “don't know” to @Halc question "what is the distance to my elbow?", bcause there is insuficient information to form an answer.

All observers willl measure the same value, won't they? They will just disagree on the simultaneity of clocks involved in the measuring procedure and the "length" of the units of measurement.

Bob's bodycam footage provides observational evidence to the contrary.

No it doesn't, it only shows movement relative to Bob's ship.

Hopefully this gets addressed by the point below.

If your intention was to discuss LET or Poincaré-Lorentz, it would have been better to start there rather than this route which has made things difficult for yourself.
I have a great deal of respect for Poincaré and there is no doubt that he almost developed the theory of relativity. In 1905 he said “It seems that this impossibility to disclose experimentally the absolute motion of the earth is a general law of nature ; we are led naturally to admit this law, which we shall call the Postulate of Relativity, and to admit it unrestrictedly”, if he had only taken the step of fully accepting the implications of this we would now be referring to Poincaré’s theory of relativity.

Some key points to the overall discussion:

1) I'm not arguing that the Einsteinian interpretation is inconsistent, I'm arguing that its self-consistency stems from its assuming its conclusion, an assumption which I am arguing is contradicted by [implied] obervational evidence - implied by the thought experiment used to explain it.

2) I am advocating for a Lorentz-Poincare style interpretation. It would have been possible to start with this - it represents just one route to the possible conclusion. I have found however, that people have a certain number of preconceptions about the LP interpretion. They assume that it must rely on an Ether and that it can only be formulated as a dynamical theory. An LP style formulation can be derived in an entirely kinematical manner, following the Einsteinian approach - as I will try to outline below.

Related to this, the LP interpretation can be divested of an undetectable Ether - given it plays no [detectable] role in anything. This leaves us with an absolute reference frame. Essentially, we don't need an absolute reference frame, we need a privileged referece frame that defines "true time". There are 2 posssible approaches to removing the need for this privileged reference frame:
- my preferred route is simply removing the idea that there is a "true time" - an atemporal interpretation does this.
- altternatiely, we can simply use a privileged reference frame for the definition of our units of measurement. As a matter of operational necessity, the rest frame of the Earth plays this role because that is how we have defined our units of measurement, for use in real world experiments.

This is not the kinematical derivation, but it addresses some possible "background" issues.

3) The clock synchronisation thought experiment can be taken to represent a possible real-world, experimental set-up that can be used to test the assumption of Einstein's clock synchronisation convention - if the assumption is determined to be invalidated, then we are left with an alternative kinematical interpretation that has been derived without reference to any form of dynamics, luminiferous ether, or absolute reference frame.



As per the the Synchronisation Convention, the journey time for a light signal from clock A to clock B is assumed to be the same as the journey time from B to A. This equates to assuming the simultneity of clock synchronisation events. In the thought experiment with Alice and Bob, their emitters and their 2 clocks, we effectively have 3 examples of this in the one set-up.

The thought experiment can be seen as a testing of this assumption. So what is the outcome? Basically, every relatively moving observer provides observational evidence that the clocks are not synchronised i.e. that the clock synchronisation events were not simultaneous. This is juxtaposed with Alice's assumption - in the face of contradictory empirical evidence - that her clocks are synchronised.

Maintaining this assumption leads, by way of necessity, to the conclusion of relativity of simultaneity but only because the "events which are simultaneous in one frame...." part of the definition is assumed i.e. the conclusion is assumed.

Maintaining this assumption requires us to accept a position where observers can be both right and wrong about oberved physical phenomena; a seeming paradox in anyone's language but not in the Einsteinian interpretion of relativity; however, it's self-consistency is entirely based on its circularity.

The alternative is one where we equally have to accept that observers are both right and wrong, but it is the infintiely more palatable case where obervers are mistaken in their assumptions and it is the observational evidence which is correct. Drop the assumption of simultneity of clock synchronisation events (in "stationary frame") and the Relativity of Simultaneity simply disappears.

Upon dropping the assumption of simultaneity of clock synchronisation events we are left with a purely kinematical derivation of the theory which extends the Galilean Principle of Relativity to simultaneity/synchronisation because, when you think about it, there is no way to determine that two events are simultaneous. We can determine that light signals from two events arrive at a detector simultaneously, but this cannot be used to determine the simultaneity of those events.

[Halc]

The ship analogy and measuring relative distances is fine because at the relative velocities involved, relativistic effectss will be negligible.

Depends on how fast our respective observers go, which wasn't specified in the thought experiment.  But it has nothing to do with one observer being on a ship or a planet.

His reference frame being at rest "relative to itself" doesn't give him any information about how his reference frame is in motion relative to the light signals he uses to synchronise his clocks.

An object is not in motion relative to light.  Light does not constitute a valid reference frame.  If it was, light would be stationary in it, which would violate the constant speed of light premise.

By the way, I would also answer “don't know” to @Halc question "what is the distance to my elbow?", bcause there is insuficient information to form an answer.

All observers willl measure the same value, won't they?

How might one attempt the measurement?  Keep it simple.  The question wasn't related to a reference frame.

They will just disagree on the simultaneity of clocks involved in the measuring procedure and the "length" of the units of measurement.

You're going to use a clock to measure the distance to my elbow? 

1) I'm not arguing that the Einsteinian interpretation is inconsistent, I'm arguing that its self-consistency stems from its assuming its conclusion, an assumption which I am arguing is contradicted by [implied] obervational evidence - implied by the thought experiment used to explain it.

You've not demonstrated that.  You just assert it, not demonstrate it.  The conclusion was deduced from just the two premises.  From there, that deduced conclusion can be used to demonstrate that the view is entirely consistent, despite your assertions otherwise.
Your argument stems from favoring an interpretation that does not hold to the first of the two premises, and you are using your set of premises to show the inconsistency of a view that uses different premises.  That makes you who is using an assumption (speed and location can be a property, rather than a relation, which requires a denial of Galilean relativity) to show the inconsistency of a view that does not take that premise.
You don't say up front that you take this premise, but your arguments are all worded from this assumption.

They assume that it must rely on an Ether and that it can only be formulated as a dynamical theory.

Well you did say "Objects in the physical world can only be in motion or at rest relative to other physical objects.", and yet you talk all the time about the speed of an object without specifying the other object relative to which that speed is meaningful.  You're very self inconsistent.
So an absolute frame needs an object then according to your statement, hence the Ether.
I agree that an absolute interpretation doesn't need Ether, but you're the one who asserts that there needs to be a physical object stationary in the referenced frame.  I say no such thing.

Essentially, we don't need an absolute reference frame, we need a privileged referece frame that defines "true time".

You'll have to explain the difference to me.  If there is a privileged frame defining true time, how does it possibly not correspond to an absolute frame giving meaning to location and speed of all objects?

It would only define true time if there was a point in it not in any gravity well.  It would be simple to devise a clock that measures true time if you just computed the absolute dilation of the thing and biased the speed at which it ran by that ratio.  I defy to to compute (even approximately) that ratio, or even find a link to it.
You're probably not the person to ask since you've displayed no inclination to perform mathematics. There is no true time, and the lack of it makes it a fantasy, and is a serious point against any absolute interpretation.  It seems time is only relative.
If I could make a clock that displays true time, an alien somewhere else could do likewise.  The two clocks would be synced (within the precision of our ability to measure the time) without any communication at all.  Both would read X many true caesium vibrations since the big bang (the only sync event common to us and the aliens).  I use vibrations since the aliens aren't going to come up with Earth seconds obviously.

the rest frame of the Earth plays this role because that is how we have defined our units of measurement, for use in real world experiments.

That just means that all speeds and locations are relative to Earth. It doesn't make it absolute at all.  It is just an arbitrary selection for a standard frame.  I can frame the Alice and Bob thing in that frame and they'll again find no inconsistency.

With the exception of objects in orbit about Earth, I can think of very few real things which would find this choice of reference frame particularly practical.  The speed of Voyager space probes is not given in Earth frame.  The speed of a train or the platform?  Not Earth frame.  Really, the standard is a poor choice.  Galilean relativity came about when they realized there is a complete lack of functional choice for the standard.

3) ... then we are left with an alternative kinematical interpretation that has been derived without reference to any form of dynamics, luminiferous ether, or absolute reference frame.

You're still left with your reference to the arbitrarily selected standard frame, which makes it relative.  I don't think this is what Poincaré-Lorentz had in mind.

As per the the Synchronisation Convention, the journey time for a light signal from clock A to clock B is assumed to be the same as the journey time from B to A.

Depends on what A and B are.  The statement above is trivially not true for any A and B, but you drive it to inconsistency by taking it out of the context where A and B are defined in such a way that the statement is always true.

[the_roosh (OP)]

@Halc: this point needs addressing before we can proceed.

Einstein talked about A to B equaling B to A, not E to A equaling E to B.  So this statement has zero to do with your chosen Einstein quote.

Do you genuinely not see how it's the exact same thing? If you can't grasp this point, there is little hope that the rest will be understood:

It might dawn on you if we label the emitter as A and the clock on the left as B1 and the clock on the right as B2.

Can you see that what we effectively have, is 3 examples of Einstein's clock synchronization convention in the one Synchronisation set-up?

If you can't then I'll break it down. But until this - most basic of points - is understood, the rest cannot be understood. Because this is the assumption that is being referred to.

[Halc]

@Halc: this point needs addressing before we can proceed.

Einstein talked about A to B equaling B to A, not E to A equaling E to B.  So this statement has zero to do with your chosen Einstein quote.

Do you genuinely not see how it's the exact same thing?

I genuinely do not.
London (E) is closer to Paris (A) than to Tokyo (B).  E to A does not equal E to B.  But the distance from Paris to Tokyo (as measured along the Earth surface) is equal to the distance from Tokyo to Paris.
Einstein wasn't talking about distance, he was talking about the time it takes light to cover that distance. That time is not necessarily the same if either London or Paris is moving, so in general (ignoring the referenced definition of A and B), Einstein's statement that the time it takes light to go from A to B being the same as the time it takes going from B to A is not true.  One must take the comment in the context in which A and B were defined as Einstein defined them.

Now what are you asserting when you say A->B = B->A meaning the same thing as E->A = E->B?

It might dawn on you if we label the emitter as A and the clock on the left as B1 and the clock on the right as B2.

Can you see that what we effectively have, is 3 examples of Einstein's clock synchronization convention in the one Synchronisation set-up?

Unclear what you're talking about.  I see one setup.  Two if we count Bob's.

If you can't then I'll break it down.

Do that please.  Einstein wasn't referring to objects with A or B.  You are.  You're thus misinterpreting his statement.  Be very clear about what those things are when you drag one of Einstein's quotes out of context into your argument.

[the_roosh (OP)]

I genuinely do not.
London (E) is closer to Paris (A) than to Tokyo (B).  E to A does not equal E to B.  But the distance from Paris to Tokyo (as measured along the Earth surface) is equal to the distance from Tokyo to Paris.

The light clock set-up is based on two clocks equidistant from the emitter, so this analogy is a misrepresentation of it.

It would be more accurate to say London to Paris and London to-some-other-location-that-is-the-same-distance-from-London-as-Paris.

Einstein wasn't talking about distance, he was talking about the time it takes light to cover that distance.

So are we, but it is worth noting that the distance from clock A to clock B is, by necessity, equal to the distance from clock B to clock A.

That time is not necessarily the same if either London or Paris is moving, so in general (ignoring the referenced definition of A and B), Einstein's statement that the time it takes light to go from A to B being the same as the time it takes going from B to A is not true.

We're not concerned with this just yet. We are simply examining how the clock synchronisation set-up in the "stationary system" is [effetively] the same as in the thought experiment, and how the thought experiment represents a 3-in-one.
One must take the comment in the context in which A and B were defined as Einstein defined them.

Do that please.  Einstein wasn't referring to objects with A or B.  You are.  You're thus misinterpreting his statement.  Be very clear about what those things are when you drag one of Einstein's quotes out of context into your argument.

Einstein was talking about establishing a "common time" for two clocks A and B i.e. synchronising clocks A and B. We are talking about synchronising two clocks B1 and B2, only in a manner that is immaterially different.

Einstein was talking about 2 spatially separated clocks A and B. So, for the sake of clarity lets say that the distance from emitter (A) to clock B1 equals the distance from A to B2 - and both are equal to the distance between clock A and B from Einsteins 1905 paper.

So, Einstein's synchronisation convention talked about two trips for the single llight signal" from
1) clock A to clock B
2) clock B to clock A

the time for both journeys is assumed to be the same i.e. it is established by definition that the time for both trips are the same - the distance is the same by matter off necessity.

I made a mistake when I said there were 3 examples of the convention in 1, there are actully 4.

In the though experiment we have the following trips for the light signals. From:
1) A to B1
2) B1 to A
This is one example of the synchronisation convention in our set-up. The time for both trips is assumed to be the same - the distance is the same by matter of necessity.

3) A to B2
4) B2 to A
This is a 2nd example of the synchronisation convention in our set-up. The time for both trips is assumed to be the same - the distance is the same by matter of necessity.

5) A to B1
6) A to B2
This is the 3rd example of the synchronisation convention in our set-up. The time for both trips is assumed to be the same - the distance is the same because we specified at the ouset that both clocks were equidistant from the emitter.

7) B1 to A
B2 to A
This is a 4th example of the synchronisation convention in our set-up. The time for both trips is assumed to be the same - the distance is the same because we specified at the ouset that both clocks were equidistant from the emitter.

It might help if you replace the emitter with another clock, it might make it easier to visualise.

So, as you can see, we have 4-in-one here. If you can't see it, please say so, and I will speak only in terms of Einstein's wording in the 1905 paper, using only 2 clocks.

[Halc]

I genuinely do not.
London (E) is closer to Paris (A) than to Tokyo (B).  E to A does not equal E to B.  But the distance from Paris to Tokyo (as measured along the Earth surface) is equal to the distance from Tokyo to Paris.

The light clock set-up is based on two clocks equidistant from the emitter, so this analogy is a misrepresentation of it.

I know, but Einstein's statement that you quoted doesn't say at all what A and B are.  It was important.  It was there in the paper, but you didn't include it.

It would be more accurate to say London to Paris and London to-some-other-location-that-is-the-same-distance-from-London-as-Paris.

That lacks a verb.  I might agree that the distance from E to A is the same as E to B, but I would not agree (for the same reason as the A->B, B->A thing) that light takes the same time to traverse those two distances, without further clarification of the statement at least.  As I said, Einstein wasn't talking about objects like London and Paris.

I'm being anal about getting it exact, because it is that lack of making precise statements that is resulting in all the confusion.

Einstein wasn't talking about distance, he was talking about the time it takes light to cover that distance.

So are we, but it is worth noting that the distance from clock A to clock B is, by necessity, equal to the distance from clock B to clock A.

Agree.

That time is not necessarily the same if either London or Paris is moving, so in general (ignoring the referenced definition of A and B), Einstein's statement that the time it takes light to go from A to B being the same as the time it takes going from B to A is not true.
One must take the comment in the context in which A and B were defined as Einstein defined them.

We're not concerned with this just yet. We are simply examining how the clock synchronisation set-up in the "stationary system" is [effetively] the same as in the thought experiment, and how the thought experiment represents a 3-in-one.

Einstein did not define either A or B as a clock, but rather points in space where the clocks are located.  You seem to be using them as the clocks themselves, but you've haven't actually explicitly said so.

Einstein was talking about establishing a "common time" for two clocks A and B i.e. synchronising clocks A and B.

He never references "clock A" or "clock B".  Yes, he was talking about establishing a "common time" for two clocks at those locations, but A and B do not refer to the clocks.  I cannot emphasize that distinction enough, because you're drawing false conclusions from interpreting his quotes otherwise.

Einstein was talking about 2 spatially separated clocks A and B.

No, he was not. Read the text and what I said just above. Say it the way Einstein does if you're going to quote him.

So, for the sake of clarity lets say that the distance from emitter (A) to clock B1 equals the distance from A to B2 - and both are equal to the distance between clock A and B from Einsteins 1905 paper.

So, Einstein's synchronisation convention talked about two trips for the single llight signal" from
1) clock A to clock B
2) clock B to clock A

the time for both journeys is assumed to be the same i.e. it is established by definition that the time for both trips are the same - the distance is the same by matter off necessity.

It can easily be demonstrated otherwise, so your statement is false. If you word it the way Einstein does, the statement becomes true. This is an excellent illustration of why it is important to get all the definitions and wordings correct.

[the_roosh (OP)]

Einstein did not define either A or B as a clock, but rather points in space where the clocks are located.  You seem to be using them as the clocks themselves, but you've haven't actually explicitly said so.

My apologies, I was working on a "steelman" assumption and an assumption that reasonable inferences would be made.

I assumed that one could reasonably infer that we were talking about clocks located at A and at B in "the stationary frame" on the basis that we were talking about Eintein's clock synchronisation in "the stationary frame" - something which has repeatedly been emphasised. I also assumed that the chosen nomenclature of "Clock A" to refer to the clock at A and "Clock B" to refer to the clock at B would be intelligible to most.

He never references "clock A" or "clock B".  Yes, he was talking about establishing a "common time" for two clocks at those locations, but A and B do not refer to the clocks.  I cannot emphasize that distinction enough, because you're drawing false conclusions from interpreting his quotes otherwise.

The conclusions being drawn aren't based on this distinction. I have clarified this above.

That Einstein doesn't label the clocks A and B doesn't prevent us from doing so. The logic of the argument is unaffected by this, but it seems your ability to understand the logic is. I will take responsibility for that, as it is the job of the communicator to ensure that what they are saying is communicated in a way that the listener understands.

No, he was not. Read the text and what I said just above. Say it the way Einstein does if you're going to quote him.

For "clocks A and B" read clocks at A and at B.

So, for the sake of clarity lets say that the distance from emitter (A) to clock B1 equals the distance from A to B2 - and both are equal to the distance between clock A and B from Einsteins 1905 paper.

So, Einstein's synchronisation convention talked about two trips for the single llight signal" from
1) clock A to clock B
2) clock B to clock A

the time for both journeys is assumed to be the same i.e. it is established by definition that the time for both trips are the same - the distance is the same by matter off necessity.

It can easily be demonstrated otherwise, so your statement is false. If you word it the way Einstein does, the statement becomes true. This is an excellent illustration of why it is important to get all the definitions and wordings correct.

What can be demonstrated otherwise; which statement is false?

Bear in mind, "in the 'stationary system'" is implied - because I have repeatedly stated that it is implied.

[Halc]

I assumed that one could reasonably infer that we were talking about clocks located at A and at B in "the stationary frame" on the basis that we were talking about Eintein's clock synchronisation in "the stationary frame"

Per the premises, it works in any frame.  Said "stationary frame" is not special in that regard.
If you mean clock at A, say clock at A, not clock A.  I wouldn't insist if it wasn't important.

I also assumed that the chosen nomenclature of "Clock A" to refer to the clock at A and "Clock B" to refer to the clock at B would be intelligible to most.

You are drawing false conclusions from the alternate wording, so that wording is wrong, not just a difference of nomenclature.

That Einstein doesn't label the clocks A and B doesn't prevent us from doing so. The logic of the argument is unaffected by this

It very much is, and you very much rely on that change of meaning in your argument.  You can deny it, so I must simply insist that you say Clock at A else we will waste countless posts in disagreement of the terms.  You can say 'clock A' of course, but you cannot put that wording in Einstein's statement since the term doesn't mean "clock at A".

What can be demonstrated otherwise; which statement is false?

This one:

So, Einstein's synchronisation convention talked about two trips for the single llight signal" from
1) clock A to clock B
2) clock B to clock A

the time for both journeys is assumed to be the same i.e. it is established by definition that the time for both trips are the same

There is no definition of anything that asserts that time for light to travel from one object to another equals the time to travel between them the other way.  It is pretty easy to come up with a counterexample showing this, as I've done in prior posts.

Bear in mind, "in the 'stationary system'" is implied - because I have repeatedly stated that it is implied.

If the clocks are moving in that stationary system, then Einstein's statement (A and B being locations) would be true but your statement (A and B being clocks) would be false.

I say all this because you very much try to apply Einstein's statement to Bob's moving clocks and assert that there is some sort of contradiction going on.  The contradiction goes away if A and B are locations instead of clocks.

[the_roosh (OP)]

I assumed that one could reasonably infer that we were talking about clocks located at A and at B in "the stationary frame" on the basis that we were talking about Eintein's clock synchronisation in "the stationary frame"

Per the premises, it works in any frame.  Said "stationary frame" is not special in that regard.
If you mean clock at A, say clock at A, not clock A.  I wouldn't insist if it wasn't important.

I also assumed that the chosen nomenclature of "Clock A" to refer to the clock at A and "Clock B" to refer to the clock at B would be intelligible to most.

You are drawing false conclusions from the alternate wording, so that wording is wrong, not just a difference of nomenclature.

That Einstein doesn't label the clocks A and B doesn't prevent us from doing so. The logic of the argument is unaffected by this

It very much is, and you very much rely on that change of meaning in your argument.  You can deny it, so I must simply insist that you say Clock at A else we will waste countless posts in disagreement of the terms.  You can say 'clock A' of course, but you cannot put that wording in Einstein's statement since the term doesn't mean "clock at A".

What can be demonstrated otherwise; which statement is false?

This one:

So, Einstein's synchronisation convention talked about two trips for the single llight signal" from
1) clock A to clock B
2) clock B to clock A

the time for both journeys is assumed to be the same i.e. it is established by definition that the time for both trips are the same

There is no definition of anything that asserts that time for light to travel from one object to another equals the time to travel between them the other way.  It is pretty easy to come up with a counterexample showing this, as I've done in prior posts.

Bear in mind, "in the 'stationary system'" is implied - because I have repeatedly stated that it is implied.

If the clocks are moving in that stationary system, then Einstein's statement (A and B being locations) would be true but your statement (A and B being clocks) would be false.

I say all this because you very much try to apply Einstein's statement to Bob's moving clocks and assert that there is some sort of contradiction going on.  The contradiction goes away if A and B are locations instead of clocks.

OK.

I suspect you are in danger of committing the reification fallacy by implying that Alice's spaceship is at rest relative to a set of imaginary, mathematical coordinates, but that remains to be seen.

Does this clarification suffice:
In the "stationary system" i.e. Alice's spaceship, Alice marks out (with chalk/spraypaint/whatever) three points A, B1 and B2.

At point A she puts an emitter with a clock that has the letter A painted on it. At points B1 and B2 she positions one clock [at each point] painted with B1 and B2 respectively. All of these components are secured to the spaceship at the points marked on the floor of the spaceship.

Alice, and all the components for her, synchronization procedure - including the points ( A and B) marked on the floor - are co-moving with the spaceship in a state of inertial motion?

Any objections to this so far?

[Halc]

I suspect you are in danger of committing the reification fallacy by implying that Alice's spaceship is at rest relative to a set of imaginary, mathematical coordinates, but that remains to be seen.

It's a thought experiment, so the frame is as imaginary as Alice.  If you're going to declare that fallacious, then all such thought experiments are fallacious.
Secondly, frames do not provide coordinates, only relative ones.  One needs to specify an origin to make it into a coordinate system.

Does this clarification suffice:
In the "stationary system" i.e. Alice's spaceship, Alice marks out (with chalk/spraypaint/whatever) three points A, B1 and B2.

That works, sure.

At point A she puts an emitter with a clock that has the letter A painted on it. At points B1 and B2 she positions one clock [at each point] painted with B1 and B2 respectively. All of these components are secured to the spaceship at the points marked on the floor of the spaceship.

Bolted to the floor is the way I put it I think in a prior post.

Alice, and all the components for her, synchronization procedure - including the points ( A and B) marked on the floor - are co-moving with the spaceship in a state of inertial motion?

Any objections to this so far?

None.  We've added a ship to which the object are attached and the marks made. Is the purpose of it to have something more concrete to represent the frame?

I recall Einstein also using physical frames like this on which marks were made and such.

[the_roosh (OP)]

It's a thought experiment, so the frame is as imaginary as Alice.  If you're going to declare that fallacious, then all such thought experiments are fallacious.

The thought experiment represents a [plausible]  real-world experimental set-up i.e. one which could manifest itself in the physical world. The same canot be said of invisible mathematical coorinates.

Secondly, frames do not provide coordinates, only relative ones.  One needs to specify an origin to make it into a coordinate system.

Duly noted.

Does this clarification suffice:
In the "stationary system" i.e. Alice's spaceship, Alice marks out (with chalk/spraypaint/whatever) three points A, B1 and B2.

That works, sure.

At point A she puts an emitter with a clock that has the letter A painted on it. At points B1 and B2 she positions one clock [at each point] painted with B1 and B2 respectively. All of these components are secured to the spaceship at the points marked on the floor of the spaceship.

Bolted to the floor is the way I put it I think in a prior post.

None.  We've added a ship to which the object are attached and the marks made. Is the purpose of it to have something more concrete to represent the frame?

Yep and a spaceship just to free us from any psychological baggage associated with the idea of "stationary"

I recall Einstein also using physical frames like this on which marks were made and such.

Cool. We're good to go so.

A couple of things. "Event B1" refers to the light signal making physical contact with clock at B1 while "Event B2" refers to the same thing for clock at B2.

At t_0 - on her co-located clock (A), Alice sets the light pulses off towards clocks B1 and B2 (which are still bolted to the floor); clock A is ticking uniformly - at any rate it is the same for both signals; how does Alice determine what reading on clock A co-incides with event B1 and the reading on clock A that co-incides with event B2?

A point of note: I'm not asking for you to tell me what the reading is, rather how does she determines what it is? Bearing in mind that light must travel from the clocks to her so that she can actually make an observation.

[Halc]

The thought experiment represents a [plausible]  real-world experimental set-up i.e. one which could manifest itself in the physical world. The same canot be said of invisible mathematical coorinates.

Good.  The mathematical coordinates are anything but invisible.  There's numbers printed on the ship if that makes a difference to you.  It doesn't to me.  All that is needed is the clocks actually to anchor the frame, the ones we're trying to sync.  Those are quite real, not abstract.

None.  We've added a ship to which the object are attached and the marks made. Is the purpose of it to have something more concrete to represent the frame?

Yep and a spaceship just to free us from any psychological baggage associated with the idea of "stationary"

Glad you want to do that.

A couple of things. "Event B1" refers to the light signal making physical contact with clock at B1 while "Event B2" refers to the same thing for clock at B2.

Agree.  B1 for the spatial location, and event B1 or EB1 for the event that occurs there at that specific moment.

At t_0 - on her co-located clock (A), Alice sets the light pulses off towards clocks B1 and B2 (which are still bolted to the floor); clock A is ticking uniformly - at any rate it is the same for both signals; how does Alice determine what reading on clock A co-incides with event B1 and the reading on clock A that co-incides with event B2?

First of all, the clocks should be named something like C1, C2, and C0 say, which happen to be located at B1, B2, and A respectively.  C0 wasn't there before and serves little purpose.
Short answer is that nobody has synced C0 with either of the other two clocks.  The distance from A to B1 and B2 is known, so one can simply compute the time it takes for light to cover that distance, which makes an assumption of frame independent light speed.  This is valid to do since that's one of the two premises of SR, and we're doing an SR procedure here.  If B1 is distance d away from A, then C0 reads d/c at a time simultaneous with events B1 and B2.
All this (both our descriptions) is described in the Alice frame.

A point of note: I'm not asking for you to tell me what the reading is, rather how does she determines what it is? Bearing in mind that light must travel from the clocks to her so that she can actually make an observation.

Alice computes d/c.  Looking at the clock serves no purpose in any of that, but we have to know that the clock reads zero at the emit event E0, so perhaps the clock triggers the emission event when it reaches 0, or the emission event zeroes the clock that is right there.  The sole purpose of Alice seems to be that of a detector of the light signals coming back from events B1 and B2, plus she also performs computations.  She needs to be at location A when she does the detection thing just like the emitter needs to be there when it does the emit thingy.  It really doesn't matter where these things are at different times.  The clock at A needs to stay put else the computation of what it reads will be off.  I see little point in anybody actually looking at any of the clocks.  We're syncing them (a write operation), not reading them (a read op).

An alternative method to get the difference d/c, Alice could place herself off to the side of the line of the clocks somewhere equidistant from clocks C0 and C1 and note what time each reads at some moment (taking a picture if she finds it too difficult to read them both at once).  That measurement will yield the same difference between the clocks as computing d/c.

[the_roosh (OP)]

The distance from A to B1 and B2 is known, so one can simply compute the time it takes for light to cover that distance, which makes an assumption of frame independent light speed.  This is valid to do since that's one of the two premises of SR, and we're doing an SR procedure here.

Yes, we are doing an SR procedure here and the point being made is that the [clock synchronization] events, in the stationary frame,  are assumed to be simultaneous, under the SR interpretation.

Indeed, an assumption of frame independent light speed is made in the form of the assumption that the journey time from A to the clock B1 (located at point B1) is equal to the journey from A to the clock B2 (located at point B2).

Alice's computation represents a mathematical prediction that needs to be verified against observations in the physical world.

If B1 is distance d away from A, then C0 reads d/c at a time simultaneous with events B1 and B2.

This is a [mathematical] prediction, which says that the reading d/c on the physical clock C0 coincides with the EB1 and EB2. Where is the observational verification of this calculation/prediction?

Alice computes d/c.  Looking at the clock serves no purpose in any of that

It serves the very important role of checking to see if Alice's computation is confirmed by empirical observations.

Alice's computation is a prediction. Simply assuming that it is correct is assuming the conclusion.

Looking at the clock serves no purpose in any of that but we have to know that the clock reads zero at the emit event E0, so perhaps the clock triggers the emission event when it reaches 0, or the emission event zeroes the clock that is right there.  The sole purpose of Alice seems to be that of a detector of the light signals coming back from events B1 and B2, plus she also performs computations.

C0 provides the timestamp by which we determine whether EB1 and EB2 are simultaneous. As you said above: If B1 is distance d away from A, then C0 reads d/c at a time simultaneous with events B1 and B2. That is a prediction. So  looking at the clock serves the very important purpose of verifying that prediction. Afterall, Alice doesn't just assume her mathematical predictions are correct without verifying them against real world observations, does she??

So, how does Alice empirically confirm that the EB1 and EB2 coincide with the reading d/c on C0?? She simply cannot. She must assume that it is true.

Therein lies the assumption of the simultaneity of [clock synchronisation] events in the stationary system.

Therein lies the assumption of the first part of the conclusion - "events which are simultaneous in one frame" - while the second part of the conclusion- "are not simultaneous in relatively moving frames" - is based on the totality of observational evidence from all other, relatively moving observers. Hence, the conclusion is assumed i.e. RoS relies on circular reasoning.

[Halc]

Yes, we are doing an SR procedure here and the point being made is that the [clock synchronization] events, in the stationary frame,  are assumed to be simultaneous, under the SR interpretation.

Their synchronization is known, not assumed, under the SR interpretation.  The only thing assumed is the SR interpretation itself, which is a pair of premises.  There is not a third premise that these two clocks are synchronized.

Indeed, an assumption of frame independent light speed is made in the form of the assumption that the journey time from A to the clock B1 (located at point B1) is equal to the journey from A to the clock B2 (located at point B2).

Disagree.  In an alternate interpretation (say one where location and speed are properties of things instead of relations between them), speed of light might be constant, but that fact isn't frame independent.  In that alternate interpretation, the rule of light taking the same time to travel from a given location to another is also the same as the time to travel from the latter to the former.  So that rule isn't an SR specific assumption.  It is an assumption that light going one way goes the same speed as light going another way.  I am unaware of a valid interpretation that would not make that assumption, but I suppose it could exist.

Alice's computation represents a mathematical prediction that needs to be verified against observations in the physical world.

Not sure which computation you mean.  The fact of the sync?  That wasn't computed.  It was just set up so it would happen.  Alice computing or verifying isn't what made those clocks be in sync.  She's an entirely optional presence.  She may be, for some reason, unaware of the facts as have been described in these posts, but if she was, there is no assumptions going on.  If she's coming late to the party, as it were, then perhaps she needs to take additional steps to verify the sync of the clocks.

Einstein of course is demonstrating his methods, so he's less likely to rely on the conclusions of SR to make this assessment.  He needs to derive that these methods will indeed result in the clocks being in sync in this frame.  I on other hand am begging the conclusions.  If you want to challenge that, you need to demonstrate which conclusions of SR are contradictory with its premises, and therefore are invalid for me to wield in making my statements.

If B1 is distance d away from A, then C0 reads d/c at a time simultaneous with events B1 and B2.

This is a [mathematical] prediction, which says that the reading d/c on the physical clock C0 coincides with the EB1 and EB2.

Which says that event where C0 reads d/c coincides with the zeroing event of the other two clocks, in the frame in question, yes.
Calling it a prediction is incorrect, since there is no measurement proposed.  A prediction needs that.  I had proposed such a way to do a verification procedure (Alice going off to the side and taking a picture).  Even that is not a prediction. Predictions are not made in thought experiments since Alice cannot in fact perform any verification.  Predictions must be verified in real experiments.

Where is the observational verification of this calculation/prediction?

I just suggested one.  Without it, as I said, your statement above isn't a prediction, just an assertion.  SR asserts that c0 says d/c at that event.  It predicts, on the other hand, that if you run some sort of verification procedure, that it will be consistent with this value.  There are several ways to go about it.

Alice computes d/c.  Looking at the clock serves no purpose in any of that

It serves the very important role of checking to see if Alice's computation is confirmed by empirical observations.

She, being an abstract entity, can't do that.  All we can have here do is a verification procedure, but it takes a real person to actually take the measurement and verify a prediction.  All we can do with Alice is compute what will happen based on our premises.  If the theory is wrong, Alice lives in a different universe and her verifications will yield different results than would be had by a real observer.

There is in fact a 3rd premise actually to SR: That of flat spacetime.  So it works fine for Alice and Bob in their Special case of reasonably massless ships, but in reality, spacetime isn't flat so there are very much empirical differences between SR and reality.  This is why SR is considered a local theory.  Space is locally flat, but on larger scales it is not.

C0 provides the timestamp by which we determine whether EB1 and EB2 are simultaneous.

I didn't use C0.  I wasn't even aware that the clock was there in the original description.  It seemed to serve a purpose in neither the sync effort nor the verification (the reflected signal) step.  So I disagree with your comment.  C0 is baggage.

As you said above: If B1 is distance d away from A, then C0 reads d/c at a time simultaneous with events B1 and B2. That is a prediction. So  looking at the clock serves the very important purpose of verifying that prediction.

Sure, but verification of the sync of C1 and C2 doesn't need C0 at all, especially since no signal reaches C0 when it reads d/c.  All we're doing with C0 is computing what it says at various points.  I can do that with any clock anywhere, which doesn't directly verify the sync of two unrelated clocks.

Afterall, Alice doesn't just assume her mathematical predictions are correct without verifying them against real world observations, does she??

Alice does exact that.  She lives in the SR world, be it valid description of our universe or not.  The predictions are to be verified by us, so show that we live in the same sort of universe as does Alice.

So, how does Alice empirically confirm that the EB1 and EB2 coincide with the reading d/c on C0?? She simply cannot. She must assume that it is true.

She knows it's true.  Mathematics demands it.  It's the nature of what Alice is, an observer put explicitly in a universe run by SR rules.

[the_roosh (OP)]

Their synchronization is known, not assumed, under the SR interpretation.  The only thing assumed is the SR interpretation itself, which is a pair of premises.  There is not a third premise that these two clocks are synchronized.

You are conflating the mathematical description of the theory with the [plausible] real-world experiments used to verify that description. The thought experiment represents one such [plausible] experimental set-up from which we can draw inferences and make deductions about the Einsteinian/Minkowskian interpretation of the mathematics.

The predictions of the theory can be extracted from the mathematical formulation. One such prediction made by the theory pertains to the reading on the physical clock (Alice's C0) that coincides with the two events B1 and B2 - the prediction being that the clock reading [equal to] d/c will coincide with the two events i.e that the two events will be simultaneous.

This is an untestable prediction,  under the foundational assumptions of the theory, meaning that this prediction is unfalsifiable. It is a crucial prediction because the conclusion that simultaneity is relative rests entirely upon it. Given that it is an untestable prediction it can only be assumed to be true. Assuming that it is true leads, by way of necessity, to the conclusion of RoS but that is only because the first, emboldened part of the conclusion - "events which are simultaneous in one frame are not simultaneous in a relatively moving frame" - is assumed.

Without this assumption we are left with the underlined part of the conclusion above, whic is derived from the totality of empirical evidence. If Alice's assumption is dropped - in the face of this overwhelming evidence  - the RoS simply disappears. Allow the assumption and RoS is a necessity - therefore,  the conclusion must be assumed.

Disagree.  In an alternate interpretation (say one where location and speed are properties of things instead of relations between them), speed of light might be constant, but that fact isn't frame independent.  In that alternate interpretation, the rule of light taking the same time to travel from a given location to another is also the same as the time to travel from the latter to the former.  So that rule isn't an SR specific assumption.  It is an assumption that light going one way goes the same speed as light going another way.  I am unaware of a valid interpretation that would not make that assumption, but I suppose it could exist.

Consider the thought experiment and drop the assumption that Alice's  (or anyone else's) clocks are synchronised - more pointedly,  that this can be determined. Here it is the two-way speed of light that is constant. This essentially just extends the Galilean principle of relativity to the determination of simultaneity/synchronization.

]Not sure which computation you mean.  The fact of the sync?  That wasn't computed.  It was just set up so it would happen.  Alice computing or verifying isn't what made those clocks be in sync.

Precisely, clocks in the real-world aren't synchronised by the mathematical formulations of a theory. Just because Alice calculates that the events B1 and B2 are simultaneous, that doesn't necessarily make it so. Her calculation represents a prediction  - in this case an untestable/unfalsifiable one.

She's an entirely optional presence.  She may be, for some reason, unaware of the facts as have been described in these posts, but if she was, there is no assumptions going on.  If she's coming late to the party, as it were, then perhaps she needs to take additional steps to verify the sync of the clocks.

Alice is required to make observations to test the predictions of the theory.  What additional steps can she take to verify that the clocks are synced?
EDIT: If you mean standing to the side and taking a picture, then this is beset by the same issues.

Einstein of course is demonstrating his methods, so he's less likely to rely on the conclusions of SR to make this assessment.  He needs to derive that these methods will indeed result in the clocks being in sync in this frame.  I on other hand am begging the conclusions.  If you want to challenge that, you need to demonstrate which conclusions of SR are contradictory with its premises, and therefore are invalid for me to wield in making my statements.

I'm not saying it's contradictory, I'm saying it's circular. The point being, how can it be demonstrated - by way of observation - that the clocks are indeed in sync in the given frame?

Under the foundational assumptions of the theory itself, that is an untestable prediction. The accuracy of the prediction must be assumed. This assumption together with the observational evidence necessitates the conclusion that simultaneity is relative by assuming the first part of the conclusion.

Which says that event where C0 reads d/c coincides with the zeroing event of the other two clocks, in the frame in question, yes.
Calling it a prediction is incorrect, since there is no measurement proposed.  A prediction needs that.  I had proposed such a way to do a verification procedure (Alice going off to the side and taking a picture).  Even that is not a prediction. Predictions are not made in thought experiments since Alice cannot in fact perform any verification.  Predictions must be verified in real experiments.

The thought experiment represents a [plausible] real world experiment. As such, it allows us to make certain inferences and deductions.

We can extract the prediction from the mathematics. The event where C0 reads d/c coincides with the zeroing event of the other two clocks, in the frame in question, is the prediction because d/c corresponds to an observable reading on C0.

Standing off to the side and taking a photo is best by the same problems, you're still dealing with the issuesof two-way light signals.

[

I just suggested one.  Without it, as I said, your statement above isn't a prediction, just an assertion.  SR asserts that c0 says d/c at that event.  It predicts, on the other hand, that if you run some sort of verification procedure, that it will be consistent with this value.  There are several ways to go about it.

The issue is that there will remain an alternative interpretation of those results, one which doesn't assume the Simultaneity of events.

She, being an abstract entity, can't do that.  All we can have here do is a verification procedure, but it takes a real person to actually take the measurement and verify a prediction.  All we can do with Alice is compute what will happen based on our premises.  If the theory is wrong, Alice lives in a different universe and her verifications will yield different results than would be had by a real observer.

Alice represents a plausible real-world observer. As such, we can make inferences and deductions about her verification procedure i.e. what she can and can't observe.

There is in fact a 3rd premise actually to SR: That of flat spacetime.  So it works fine for Alice and Bob in their Special case of reasonably massless ships, but in reality, spacetime isn't flat so there are very much empirical differences between SR and reality.  This is why SR is considered a local theory.  Space is locally flat, but on larger scales it is not.

I am aware of that. It's fine though, the issues of determining the Simultaneity of events in the stationary frame still apply.

I didn't use C0.  I wasn't even aware that the clock was there in the original description.  It seemed to serve a purpose in neither the sync effort nor the verification (the reflected signal) step.  So I disagree with your comment.  C0 is baggage.

You used it to show the clock reading (d/c) which coincides with events B1 and B2 - how else does one determine that the events were simultaneous?
EDIT: The reflected signals [arriving back simultaneously] does not verify that the the signals arrived at B1 and B2 simultaneously, for the reasons outlined.

Sure, but verification of the sync of C1 and C2 doesn't need C0 at all, especially since no signal reaches C0 when it reads d/c.

Precisely the point! How can the simultaneity of the events be determined then?

Like it or not, that events B1 and B2 coincide with C0 reading d/c is a prediction - it's just an untestable one, for the reason you state.

All we're doing with C0 is computing what it says at various points.  I can do that with any clock anywhere, which doesn't directly verify the sync of two unrelated clocks.

Computing what the reading on a physical clock will be at the time of two given events is a prediction about the physical world. How do we verify that the calculation is in fact correct and that our mathematical model accurately represents the physical world, in this specific case - given that there is an alternative, mathematically and empirically equivalent interpretation. How do we verify that the time coordinate that we have ascribed to events B1 and B2 is actually the correct time coordinate for those events? What observation can we make to verify this.

Alice does exact that.  She lives in the SR world, be it valid description of our universe or not.  The predictions are to be verified by us, so show that we live in the same sort of universe as does Alice.

Alice assumes that she lives in an SR world, but only bcos she assumes her conclusions. Alice represents a real-world experimental set-up from which we can make deductions about the Einsteinian interpretation of the mathematical formulation and predictions.

She knows it's true.  Mathematics demands it.  It's the nature of what Alice is, an observer put explicitly in a universe run by SR rules.

How does she know it's true? It's certainly not on the basis of empirical evidence.
The idea that "the mathematics demands it" simply states that the Einsteinian/Minkowski interpretation of the mathematics demands it - there are alternative interpretations. One such demand that the mathematics makes is that a real-world, physical clock must show a reading [corresponding to] d/c to coincide with two events B1 and B2. This demand that mathematics seeks to impose upon the physical world constitutes a prediction. This prediction is to be verified by way of empirical observation because empiricism demands it.

 Afterall, if the clock doesn't show this reading to coincide with the two events, it will show that the physical world is impervious to the demands of mathematics - this particular - and crucial for the conclusion of RoS - demand.


To summarise: SR makes an untestable/unfalsifiable prediction about the simultaneity of events in a stationary frame. This prediction is critical to the conclusion that simultaneity is relative. The prediction is untestable/unfalsifiable under the foundational assumptions of SR. SR, therefore assumes the truth of its own prediction. It therefore assumes its conclusion that simultaneity is relative.

As as an observer put explicitly in a universe run by SR rules
She assumes its true just as SR assumes its true i.e. SR requires us to assume its conclusions.

[Halc]

Their synchronization is known, not assumed, under the SR interpretation.  The only thing assumed is the SR interpretation itself, which is a pair of premises.  There is not a third premise that these two clocks are synchronized.

You are conflating the mathematical description of the theory with the [plausible] real-world experiments used to verify that description.

I am not. I was quite thorough in pointing out that Alice lives in the SR universe, and the mathematical description is the territory, not the map, since it is a pure abstract mathematical universe with known rules.  The prediction/verification business is for real people to do.  If it matches what Alice sees, then the SR model is a valid description of our universe, not only hers.  If the predicted things don't match measurements, then the model isn't valid, not entirely anyway.  That's the interpretation I have of this thought experiment.  I am assuming SR interpretation, but Alice knows it because that's how I set up her environment.

The predictions of the theory can be extracted from the mathematical formulation.

Yes, and Alice's observations become predictions for us.  She cannot test that my universe corresponds to her own. Real people must verify or falsify those predictions.

One such prediction made by the theory pertains to the reading on the physical clock (Alice's C0) that coincides with the two events B1 and B2 - the prediction being that the clock reading [equal to] d/c will coincide with the two events i.e that the two events will be simultaneous. This is an untestable prediction, under the foundational assumptions of the theory, meaning that this prediction is unfalsifiable.

Given an SR interpretation of physics, there are multiple ways to test that assertion, and those methods are very much falsifiable. Given a different interpretation, I don't think the simultaneity of two clocks can be set up nor verified.

It is a crucial prediction because the conclusion that simultaneity is relativity rests entirely upon it.

If you say so.  I found the reading on clock C0 to be fairly irrelevant.  But if you find it important, do you suggest that any empirical test of C0 in Alice's frame would not yield a difference of d/c with either of the other two clocks?

Given that it is an untestable prediction it can only be assumed to be true.

I posted one way to test it.  There are others.  If it is actually untestable, then it makes no empirical difference, and the fact of it becomes irrelevant.  But it is quite testable given an SR interpretation.  If you mean to say that it is untestable without assuming an SR interpretation, then I agree.

Assuming that it is true leads, by way of necessity, to the conclusion of RoS but that is only because the first, emboldened part of the conclusion - "events which are simultaneous in one frame are not simultaneous in a relatively moving frame" - is assumed.

Very hard to parse that, but if you're saying that one needs to assume RoS is true to demonstrate that C0 coincides with C1 in Alice's frame, then I agree.  Any verification procedure relies on the interpretation.  We're demonstrating only that SR is valid, not falsifying any other interpretations.

If you think I'm trying to prove the relative interpretation, I'm not.  I lay no claim that your interpretation is wrong.  I am merely reacting to your suggestion that the relative interpretation is wrong.  If it is wrong, then a contradiction must result from assuming it.  There would be a falsification test.  You've identified no such self-contradiction.

Without this assumption we are left with the underlined part of the conclusion above, whic is derived from the totality of empirical evidence.

Your underlined statement assumes a relative interpretation.  It is not always true in that interpretation (two events might still be simultaneous in two different frames so long as motion component along the axis connecting the events is not different).  In an absolute interpretation, two simultaneous events are just that.  There is no frame dependency about it.  Alice has not performed a valid sync procedure for such an interpretation.

If Alice's assumption is dropped - in the face of this overwhelming evidence  - the RoS simply disappears.

I agree that if Alice's assumptions of the SR premises are dropped (the premises from which RoS is derived), then the RoS disappears.  I'm not sure what the 'overwhelming evidence' of which you speak is.  The statement seems to stand without mention of that.

Consider the thought experiment and drop the assumption that Alice's  (or anyone else's) clocks are synchronised - more pointedly,  that this can be determined.

I would have to drop other assumptions to do that.

Here it is the two-way speed of light that is constant. This essentially just extends the Galilean principle of relativity to the determination of simultaneity/synchronization.

I don't know what you mean when saying "the two-way speed of light that is constant".
The speed of light as measured one-way has been shown to be constant. If you disagree with that empirical fact, then demonstrate how it is wrong, and how light speed (previously totally unknown) was fairly accurately measured via a one-way test, long before they had super-accurate clocks.  The fact that they got a valid number at all means it works.  With more accurate equipment, the same test could be (and is) done today to get far more accurate results.

Her calculation represents a prediction  - in this case an untestable/unfalsifiable one.

Then it isn't a prediction.

Alice is required to make observations to test the predictions of the theory.

Sorry, no.  That's our job, not hers.  Alice would still see exactly what we say she does, but we would observer something else if the theory corresponds only to her universe but not ours.

I'm not saying it's contradictory, I'm saying it's circular. The point being, how can it be demonstrated - by way of observation - that the clocks are indeed in sync in the given frame?

It is indeed circular.  SR shows a method to sync clocks, and also to verify the same. If one assumes an SR interpretation, only only need follow the described procedures, and the clocks will be in sync as defined by that interpretation. If one assumes a different interpretation, 'simultaneous' is defined differently and  those clocks are probably not in sync.  The fact of their being in sync is interpretation dependent then.  It is a philosophical distinction.

The thought experiment represents a [plausible] real world experiment. As such, it allows us to make certain inferences and deductions.
We can extract the prediction from the mathematics. The event where C0 reads d/c coincides with the zeroing event of the other two clocks, in the frame in question, is the prediction because d/c corresponds to an observable reading on C0.

Not if there is no description of when to take the reading on the C0 clock.  Of course the reading of d/c is going to go by, so observing that doesn't in any way demonstrate its simultaneity with the zeroing events somewhere else.  A prediction needs a distinct observation.  Seeing d/c on the clock isn't it, since that time would go by whether or not that event happened at the same time as the other events or not.

Standing off to the side and taking a photo is best by the same problems, you're still dealing with the issuesof two-way light signals.

Taking a photo involves one way light.  No light need travel from the camera to anything.  It records what is seen from that event off to the side.  The picture need not be taken at any particular time.  Tomorrow is fine.

The issue is that there will remain an alternative interpretation of those results, one which doesn't assume the Simultaneity of events.

Agree, except I don't see how that is the issue.  Yes, I am assuming one interpretation when performing the procedure.  The procedure is entirely wrong for a different interpretation.  My goal is to demonstrate the validity of the one interpretation, not that it is the only valid one.

C0 is baggage.

You used it to show the clock reading (d/c) which coincides with events B1 and B2 - how else does one determine that the events were simultaneous?

Your OP described it:

The light pulses are reflected to the observer at the mid-point and arrive simultaneously. The observer concludes that their clocks are synchronised because they know the speed of light and the distance to the clocks, and because the light pulses returned simultaneously.

That is the verification procedure, and it didn't involve a clock C0 at all.  No mention is made of it.  If you want to introduce a 3rd clock that is not in sync, a similar procedure can be used to verify how far out of sync (d/c) it is.  But the original story didn't have this clock at all.  Not sure why you introduced it.  I think I named it, but I didn't propose its existence.

How do we verify that the calculation is in fact correct and that our mathematical model accurately represents the physical world, in this specific case - given that there is an alternative, mathematically and empirically equivalent interpretation.

If there was such a test, they would not be interpretations, but competing theories.  There is no such test.  I've laid no claim that the relative interpretation is the correct one.

Alice assumes that she lives in an SR world, but only bcos she assumes her conclusions.

More like the other way around, but yes, it is sort of circular.

How does she know it's true? It's certainly not on the basis of empirical evidence.

Alice is doing things the relative way because we're testing that interpretation via this thought experiment.
One is also quite capable of considering the exact same scenario through a different interpretation, in which case Alice's clocks are not synced at all.

One such demand that the mathematics makes is that a real-world, physical clock must show a reading [corresponding to] d/c to coincide with two events B1 and B2. This demand that mathematics seeks to impose upon the physical world constitutes a prediction.

No it doesn't, because in a different interpretation, C0 reading d/c doesn't coincide with events B1 or B2, yet no empirical test would distinguish the two cases.  That lack of distinction makes it not a prediction.  A prediction needs an empirical distinction.

To summarise: SR makes an untestable/unfalsifiable prediction about the simultaneity of events in a stationary frame. This prediction is critical to the conclusion that simultaneity is relative.

That's not the conclusion I'm going for. I'm concluding that simultaneity could be relative. What made you think I'm asserting otherwise? You're the one suggesting that it can not be, and that suggestion is why I'm here challenging it.

It therefore assumes its conclusion that simultaneity is relative.

I actually can think of no scientific theory that does this: asserting itself.  No theory claims to be the correct one.  They only claim to be self-consistent.

[the_roosh (OP)]

I am not. I was quite thorough in pointing out that Alice lives in the SR universe, and the mathematical description is the territory, not the map, since it is a pure abstract mathematical universe with known rules.  The prediction/verification business is for real people to do.  If it matches what Alice sees, then the SR model is a valid description of our universe, not only hers.  If the predicted things don't match measurements, then the model isn't valid, not entirely anyway.  That's the interpretation I have of this thought experiment.  I am assuming SR interpretation, but Alice knows it because that's how I set up her environment.
...
Yes, and Alice's observations become predictions for us.  She cannot test that my universe corresponds to her own. Real people must verify or falsify those predictions.
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[Taken from below]
Sorry, no.  That's our job, not hers.  Alice would still see exactly what we say she does, but we would observer something else if the theory corresponds only to her universe but not ours.

It seems that allowing the assumption that Alice lives in an SR universe is hindering your ability draw the necessary conclusions. It is more accurate to say that Alice is trying to determine what kind of universe she lives in.

As the thought experiment is a plausible, real-world one, we can speak of it as though it has actually been conducted because it is an accurate representation of what the different interpretations say will occur. If the experiment weren't to unfold in the way the thought experiment does then the theory would be invalidated, which is why we can assume that the thought experiment maps to the real world. It allows to consider the observations that would be made as a matter of necessity. From this, we can draw inferences and deductions about those real world observations and thereby glean more information to help us (and Alice) determine if we actually do live in an SR universe.

The mathematical description is open to interpretation; it makes predictions which can be used to determine if the description represents an accurate map of the territory and by which we may be able to distinguish between the interpretations.

Given an SR interpretation of physics, there are multiple ways to test that assertion, and those methods are very much falsifiable. Given a different interpretation, I don't think the simultaneity of two clocks can be set up nor verified.

It is not a given. I see from the points you make below that you seem to have made a presupposition that I am claiming that the Einsteinian interpretation of relativity isn't self-consistent. I'm fairly certain that I was extremely explicit earlier in the thread that this was not the contention. The contention has been that it's self-consistency derives from it's circularity.

I have clearly been arguing the proposition that RoS is based on circular logic. Something you expressly admit below.

If you say so.  I found the reading on clock C0 to be fairly irrelevant.  But if you find it important, do you suggest that any empirical test of C0 in Alice's frame would not yield a difference of d/c with either of the other two clocks?

You found it relevant enough to ascribe a reading to it to coincide with the events B1 and B2. A resding that is predicted by the Einsteinian interpretation of the mathematics - what else could provide the "common time" necessary for determining the Simultaneity of the events?

There is no such test, which can make such a determination, which is why the assumption should be dropped - especially given the preponderance of evidence of non-simultaneity.

I posted one way to test it.  There are others.

The journey for the signals from the events to the camera is effectively the same idea as returning to the mid-point, it just moves the location. As long as the camera is equidistant from B1 and B2, the same issue applies.
It might help to visualize the set-up in such a way that the light is obscured until it reaches B1 and B2.

  If it is actually untestable, then it makes no empirical difference, and the fact of it becomes irrelevant.

The conclusion that Simultaneity is relative rests entirely upon it. So, it has more than a little relevance.

  But it is quite testable given an SR interpretation.  If you mean to say that it is untestable without assuming an SR interpretation, then I agree.

It's not testable given any interpretation, especially that of SR - under the foundational assumptions of the theory itself, it is untestable/unfalsifiable.

It is assumed under SR, not tested. Meaning the conclusion of RoS (in SR) is assumed.

Very hard to parse that, but if you're saying that one needs to assume RoS is true to demonstrate that C0 coincides with C1 in Alice's frame, then I agree.  Any verification procedure relies on the interpretation.  We're demonstrating only that SR is valid, not falsifying any other interpretations.

I can't speak for you, but I have been trying to demonstrate that the Relativity of Simultaneity is based on circular reasoning. That is, that SR assumes its conclusion.

The Relativity of Simultaneity says that "events which are simultaneous in one frame are not simultaneous in another, relatively moving frame". As you are in agreement with, SR assumes the simultaneity of events in one frame. That is, the first part of the conclusion is assumed (in bold above). Without this assumption there is no conclusion of RoS - hence, it is circular, hence SR assumes its conclusion.

If you think I'm trying to prove the relative interpretation, I'm not.  I lay no claim that your interpretation is wrong.  I am merely reacting to your suggestion that the relative interpretation is wrong.  If it is wrong, then a contradiction must result from assuming it.  There would be a falsification test.  You've identified no such self-contradiction.

Your underlined statement assumes a relative interpretation.  It is not always true in that interpretation (two events might still be simultaneous in two different frames so long as motion component along the axis connecting the events is not different).  In an absolute interpretation, two simultaneous events are just that.  There is no frame dependency about it.  Alice has not performed a valid sync procedure for such an interpretation.

As I have been at pains to point out, I was not trying to demonstrate that SR is self-contradictory. I have been trying to demonstrate that its self-consistency derives from its circularity.

As you have pretty explicitly agreed that RoS is based on circular reasoning i.e. that the conclusion is assumed, it seems we are in agreement in this regard.

I agree that if Alice's assumptions of the SR premises are dropped (the premises from which RoS is derived), then the RoS disappears.  I'm not sure what the 'overwhelming evidence' of which you speak is.  The statement seems to stand without mention of that.
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I would have to drop other assumptions to do that.

Alice only needs to modify the premises from which the mathematical predictions of SR is derived. If she says that the speed of light is always measured to be the same, she frees herself from the assumption of Simultaneity of events in her stationary system and she no longer needs to employ circular reasoning to arrive at one of the most fundamental conclusions of SR - that Simultaneity is relative.

I don't know what you mean when saying "the two-way speed of light that is constant".
The one-way speed of light has been shown to be constant. If you disagree with that empirical fact, then demonstrate how it is wrong, and how light speed (previously totally unknown) was fairly accurately measured via a one-way test, long before they had super-accurate clocks.  The fact that they got a valid number at all means it works.  With more accurate equipment, the same test could be (and is) done today to get far more accurate results.

The "one-way" speed of light, from a source to a detector, cannot be measured independently of a convention as to how to synchronize the clocks at the source and the detector. What can however be experimentally measured is the round-trip speed (or "two-way" speed of light) from the source to the detector and back again. Albert Einstein chose a synchronization convention (see Einstein synchronization) that made the one-way speed equal to the two-way speed

Then it isn't a prediction.

It makes a truth claim about the configuration of a physical system, it is therefore a prediction. That it is untestable/unfalsifiable under the foundational assumptions of the theory itself doesn't change this, it simply represents an undesirable aspect of the theory.

It is indeed circular.

Precisely the point being made. Hence, the conclusion that Simultaneity is relative is circular and therefore untestable/unfalsifiable.

  SR shows a method to sync clocks, and also to verify the same. If one assumes an SR interpretation, only only need follow the described procedures, and the clocks will be in sync as defined by that interpretation.

No such [empirical] verification is described. The foundational assumptions of the theory explicitly state that it must be assumed.

If one follows the procedures outlined under the SR interpretation one still does not verify that the clocks are synced, in the stationary system, it is assume that they are synced. This means that SR assumes the conclusion of frame dependent simultaneity.

If one assumes an SR interpretation...

You have made repeated statements to this effect. Let me put it in context:
If one assumes that the Flying Spaghetti Monster created the initial conditions of the universe, then one will conclude that the FSM is responsible for the current state of the Universe.

If one assumes a different interpretation, 'simultaneous' is defined differently and  those clocks are probably not in sync.  The fact of their being in sync is interpretation dependent then.  It is a philosophical distinction.

One can simply drop the assumption of Simultaneity altogether - effectively extending the Galilean Principle of Relativity to the notions of Simultaneity/Synchronization.

Not if there is no description of when to take the reading on the C0 clock.  Of course the reading of d/c is going to go by, so observing that doesn't in any way demonstrate its simultaneity with the zeroing events somewhere else.  A prediction needs a distinct observation.  Seeing d/c on the clock isn't it, since that time would go by whether or not that event happened at the same time as the other events or not.

SR predicts that the signals will make contact with B1 and B2 at a time d/c. This time d/c corresponds to the reading on a real-world, physical clock. In this sense SR makes a truth claim about the configuration of a physical system i.e. it makes a prediction.

A prediction which is untestable/unfalsifiable under its own foundational assumptions.

Taking a photo involves one way light.  No light need travel from the camera to anything.  It records what is seen from that event off to the side.  The picture need not be taken at any particular time.  Tomorrow is fine.

Light from the events B1 and B2 must travel to the camera. This is equivalent to traveling back to the mid-point,  just that the location for receiving the reflected signals is moved.

Agree, except I don't see how that is the issue.  Yes, I am assuming one interpretation when performing the procedure.  The procedure is entirely wrong for a different interpretation.  My goal is to demonstrate the validity of the one interpretation, not that it is the only valid one.

The validity of the interpretation is very questionable. The preponderance of evidence is against the assumption of Simultaneity of events in the stationary system.

Remember, as you have repeatedly stated, the Simultaneity of those events must be assumed not observered empirically.

All other observers provide empirical evidence that the events weren't simultaneous.

That is the verification procedure, and it didn't involve a clock C0 at all.  No mention is made of it.  If you want to introduce a 3rd clock that is not in sync, a similar procedure can be used to verify how far out of sync (d/c) it is.  But the original story didn't have this clock at all.  Not sure why you introduced it.  I think I named it, but I didn't propose its existence.

The signals returning simultaneously to the emitter does not verify that the signals made physical contact with B1 and B2 at a time corresponding to a reading of d/2 on C0 i.e. it doesn't confirm that the zeroing events were simultaneously - you have unequivocally stated that this must be assumed,  not verified.

The 3rd clock was introduced to try and make the set-up more similar to Einstein's formulation. You kindly named the third clock "C0" and told us the prediction that SR makes about the reading on that clock that should coincide with events B1 and B2 - that is, you pointed out the claim that SR makes about the configuration of the physical system.

If there was such a test, they would not be interpretations, but competing theories.  There is no such test.  I've laid no claim that the relative interpretation is the correct one.

We are in total agreement then. The conclusion that Simultaneity is relative i.e. that it is frame dependent is based on circular reasoning.  As such, it is an untestable/unfalsifiable prediction/conclusion/hypothesis however you want to frame it.

More like the other way around, but yes, it is sort of circular.

Hahaha forgive me, I read this to mean SR assumes its conclusions, so Alice assumes she lives in an SR universe.

I've clarified this above.  Alice represents us trying to determine what kind of Universe she/we live in.

Alice is doing things the relative way because we're testing that interpretation via this thought experiment.
One is also quite capable of considering the exact same scenario through a different interpretation, in which case Alice's clocks are not synced at all.

Alice is simply performing an experiment to try and help her determine what kind of universe she/we lives in. From her plausibly actualised observations we can draw conclusions about the universe thst we live in.

One can simply drop any assumptions about the Simultaneity of events in a stationary system.

No it doesn't, because in a different interpretation, C0 reading d/c doesn't coincide with events B1 or B2, yet no empirical test would distinguish the two cases.  That lack of distinction makes it not a prediction.  A prediction needs an empirical distinction.

SR makes a statement about the configuration of the physical system, it is therfore a prediction. That it is untestable/unfalsifiable under the foundational assumptions of the theory represents an issue with the theory itself.

That's not the conclusion I'm going for. I'm concluding that simultaneity could be relative. What made you think I'm asserting otherwise? You're the one suggesting that it can not be, and that suggestion is why I'm here challenging it.

Either simultaneity is relative or it isn't.

The conclusion that simultaneity is relative requires the conclusion to be assumed.

The conclusion that it isn't relative simply require us to not make the assumption that it is. It simply requires us to consider the totality of empirical evidence only and not append any assumptions to that evidence; assumptions that are contradicted by the evidence.

It therefore assumes its conclusion that simultaneity is relative.

I actually can think of no scientific theory that does this: asserting itself.  No theory claims to be the correct one.  They only claim to be self-consistent.

Circular logic is the most self-consistent logic there can be. That doesn't mean that the circle cannot be broken however

[Halc]

It seems that allowing the assumption that Alice lives in an SR universe is hindering your ability draw the necessary conclusions. It is more accurate to say that Alice is trying to determine what kind of universe she lives in.

She going about that task all wrong then.  She's doing this funny procedure with some clocks and light equipment.  At no point is she instructed to perform some kind of test that would distinguish between one kind of universe and another.  She's in the wrong thought experiment.
If that's her task, why do we have her doing this unrelated procedure?

As the thought experiment is a plausible, real-world one, we can speak of it as though it has actually been conducted because it is an accurate representation of what the different interpretations say will occur. If the experiment weren't to unfold in the way the thought experiment does then the theory would be invalidated, which is why we can assume that the thought experiment maps to the real world.

If the experiment weren't to unfold in the way the thought experiment does then both interpretations would be wrong, since both interpretations predict the same observations for Alice.

It allows to consider the observations that would be made as a matter of necessity. From this, we can draw inferences and deductions about those real world observations and thereby glean more information to help us (and Alice) determine if we actually do live in an SR universe.

What observation are you talking about?  You didn't describe any such observation.

The mathematical description is open to interpretation;

Yes.  That means the exact opposite of what you say next:

it makes predictions which can be used to determine if the description represents an accurate map of the territory and by which we may be able to distinguish between the interpretations.

If it made such a prediction, the description would not be open to interpretation.  So this is nonsense.  There have been attempts at doing just that, whenever the test comes up positive for the relative interpretation, the test is declared invalid rather than being declared actual falsification of said alternate interpretation.  Translation: the testers commit selection bias.

I see from the points you make below that you seem to have made a presupposition that I am claiming that the Einsteinian interpretation of relativity isn't self-consistent. I'm fairly certain that I was extremely explicit earlier in the thread that this was not the contention. The contention has been that it's self-consistency derives from it's circularity.

It does, but so does yours.  That's the nature of any interpretation of something.  The circularity is necessary.  Self consistency means there are no contradictions along the circle.
The two interpretations have differing definitions of simultaneity, so each must assume its own definition when describing simultaneous events.  That's the circular conclusion that must be employed.  But the differing definitions are not premises, but rather necessities that follow from the premises.  So in that sense, neither interpretation is circular.

You found it relevant enough to ascribe a reading to it to coincide with the events B1 and B2. A resding that is predicted by the Einsteinian interpretation of the mathematics - what else could provide the "common time" necessary for determining the Simultaneity of the events?

An actual measurement, as described, also predicted by (and assuming) that interpretation.

There is no such test, which can make such a determination, which is why the assumption should be dropped - especially given the preponderance of evidence of non-simultaneity.

No claim of simultaneity was made.  Alice tested that the clocks are simultaneous in this one frame (the ship in the latest description).  That test relied on the interpretation of choice, yes.  She performed no test to attempt a falsification of one interpretation or the other.  Nobody in the thought experiment attempted to do an absolute sync of the two clocks.  If they desired to do so, the procedure they're using is completely wrong.

  If it is actually untestable, then it makes no empirical difference, and the fact of it becomes irrelevant.

The conclusion that Simultaneity is relative rests entirely upon it. So, it has more than a little relevance.

Well Alice didn't conclude that.  She performed a frame dependent test that makes syntactic sense only in the one interpretation.  If it makes you feel better, she demonstrated (in the absence of interpretation assumptions) that C1 and C2 appear simultaneous in that frame and wrote off the issue of their being actually simultaneous or not as having no practical significance, only philosophical significance.  She'd be right about that.

It is assumed under SR, not tested. Meaning the conclusion of RoS (in SR) is assumed.

I can't speak for you, but I have been trying to demonstrate that the Relativity of Simultaneity is based on circular reasoning. That is, that SR assumes its conclusion.

It does not assume its conclusions (RoS for instance). The conclusions are all derived.  You repeat this claim without evidence. Show where in Einstein's paper a conclusion is assumed before it is derived.
RoS is quite trivially demonstrated given the premises. There is no need to assume it.

The Relativity of Simultaneity says that "events which are simultaneous in one frame are not simultaneous in another, relatively moving frame". As you are in agreement with, SR assumes the simultaneity of events in one frame.

There are no specific events which are being assumed simultaneous.  It (the whole thing, not the bolded part) is a statement of RoS which can be applied to events already found to be (not assumed to be) simultaneous in a frame.

That is, the first part of the conclusion is assumed (in bold above).

The bolded part makes no assertions.  It is effectively a conditional phrase: "If two events are simultaneous in some frame".  It is not assuming any specific events are in fact simultaneous since no events are identified.  The meaning of 'simultaneous in a frame' is already established at the time such a statement would be made.

Without this assumption there is no conclusion of RoS - hence, it is circular, hence SR assumes its conclusion.

The statement above is not one concluding RoS.  It is stating (not concluding) that two such events meeting the qualification in bold part might also meet the qualification in the underlined part.  It uses the already established (not assumed) RoS to do this.

As you have pretty explicitly agreed that RoS is based on circular reasoning i.e. that the conclusion is assumed.

I never said any conclusion was assumed.  All were derived. It is circular in that it assumes (never proves) its own premises.  It results in a relative definition of 'simultaneous', but that again is derived, not assumed.

Alice is performing a relative procedure (assuming a relative interpretation) and concluding that two events are simultaneous in a way meaningful only to that interpretation. That's the circularity of it that I'm talking about.

Alice only needs to modify the premises from which the mathematical predictions of SR is derived. If she says that the speed of light is always measured to be the same, she frees herself from the assumption of Simultaneity of events in her stationary system and she no longer needs to employ circular reasoning to arrive at one of the most fundamental conclusions of SR - that Simultaneity is relative.

For the record, SR theory proper does not assert constant light speed. It only presumes the frame independent appearance of it. It is the relative interpretation of SR theory that makes the metaphysical assumption that said light speed actually is constant.  This metaphysical interpretation is probably the most mainstream interpretation, but being metaphysics, lacks any kind of evidence to support it.  Einstein himself very much used the relative interpretation.

That said, in making that statement above, you burden yourself with an assumption that there is a stationary system.  If we're going to drop the metaphysical assumption that light speed is (not just appears) constant in any frame, we also need to drop the stationary frame concept.  Not doing so would be 'circular reasoning' the way you seem to use the term.
So we drop all these assumptions. Now what? In the absence of such assumptions, where do we go?

The "one-way" speed of light, from a source to a detector, cannot be measured independently of a convention as to how to synchronize the clocks at the source and the detector.

They had a convention.  This is pre-relativity, so they used Earth frame without knowing that it mattered.  They were (in hindsight) measuring the speed of light as it appeared in that frame.  It wasn't until considerably later that measurements became accurate enough to conclude the frame independence of that appearance.

You put a clock far away and observe it from a distance.  When it appears to read zero, you zero the local clock. That's the sync convention that was used.  The two clocks, unchanged, should always locally appear to read the same value.
If light speed was infinite, then the local clock would always be in sync with the observed value on the distant clock (and in fact would be the actual value).  If light speed is some finite number, then changing the distance between the observer and the distant clock should (and did) change the sync between the two clocks.  The distant one would appear to log less time (run slower) as it moved further away and more time was needed for light to get from there one-way to the observer.  It would appear to get ahead as the distant clock grew closer.
By observing this change in the sync between the two clocks, a remarkably accurate measurement of one-way light speed was taken.

Albert Einstein chose a synchronization convention (see Einstein synchronization) that made the one-way speed equal to the two-way speed

The people back then used a different convention, but one just as valid.  In particular, it didn't rely on two-way light trips.  There were no mirrors involved.

Then it isn't a prediction.

It makes a truth claim about the configuration of a physical system, it is therefore a prediction.

You and I have quite a different definition of what a prediction is.  I have an empirical definition, not a metaphysical one.

If one assumes an SR interpretation...

You have made repeated statements to this effect. Let me put it in context:
If one assumes that the Flying Spaghetti Monster created the initial conditions of the universe, then one will conclude that the FSM is responsible for the current state of the Universe.

How is the premise a conclusion?  It's just a tautology.  Assuming that I have 5 apples, then I have 5 apples.  Yes, that's circular, but not invalid.  I don't consider my having 5 apples to be a conclusion, but rather the premise.  RoS on the other hand is not a premise.

One can simply drop the assumption of Simultaneity altogether - effectively extending the Galilean Principle of Relativity to the notions of Simultaneity/Synchronization.

Don't know what you mean by this.  The first part seems to suggest that simultaneity is meaningless.  The second part seems to suggest a different metaphysical assumption, and you seem to balk at such assumptions, labeling any conclusions drawn from them to be circular and thus somehow fallacious.

Taking a photo involves one way light.  No light need travel from the camera to anything.  It records what is seen from that event off to the side.  The picture need not be taken at any particular time.  Tomorrow is fine.

Light from the events B1 and B2 must travel to the camera.

We were talking about testing C0, so it would be light from A and B1 that must travel to the camera.  We've already done the procedure for B1 and B2.  You introduced this 3rd clock and asked how to verify how much it is out of sync with the other two.

Yes, I am assuming one interpretation when performing the procedure.  The procedure is entirely wrong for a different interpretation.  My goal is to demonstrate the validity of the one interpretation, not that it is the only valid one.

The validity of the interpretation is very questionable.

You said you accepted the interpretation as valid. Now you say otherwise.

The preponderance of evidence is against the assumption of Simultaneity of events in the stationary system.

So you assert, but this evidence is never presented.  So this is an empty assertion.  Please don't make statements like this without referencing at least one piece of evidence that contradicts what the interpretation says should be observed.  I don't make this statement about your pet interpretation despite my thinking that it has metaphysical issues.

Remember, as you have repeatedly stated, the Simultaneity of those events must be assumed not observered empirically.

Where did I say that?  I assumed an actual constant relative speed of light.  I cannot prove that it doesn't just appear to be that way.  I made no more assumptions than that. I did not conclude from that assumption that those events were simultaneous.

All other observers provide empirical evidence that the events weren't simultaneous.

Nobody provided any evidence that the events were simultaneous or not simultaneous.  I was waiting for you to introduce Bob and make such a statement.  Took you a while...
Your assertion is baseless. Everybody (Bob and whoever else might be out there) provided empirical evidence that did nothing except confirm what Alice concludes.

The signals returning simultaneously to the emitter does not verify that the signals made physical contact with B1 and B2 at a time corresponding to a reading of d/2 on C0 i.e. it doesn't confirm that the zeroing events were simultaneously

I didn't claim that. You are putting a lot of words in my mouth.  How many times must I point out claims that I didn't make? The signals returning simultaneously to the detector verify that C1 and C2 are in sync in that frame, and do not constitute any sort of verification concerning C0.
I also said that the reading on the C0 clock at the time did not play any role in the verification of what Alice is attempting to do with C1 and C2.
To be picky: B1 and B2 are locations, and one cannot make physical contact with a location.
That was probably a typo.  You mean physical contact with the clocks C1 and C2 bolted there.

The 3rd clock was introduced to try and make the set-up more similar to Einstein's formulation. You kindly named the third clock "C0" and told us the prediction that SR makes about the reading on that clock that should coincide with events B1 and B2 - that is, you pointed out the claim that SR makes about the configuration of the physical system.

Yes to all that, but none of that describes a verification procedure for it.
Did Einstein put a 3rd clock between the two in his description of the convention to sync the first two?  Don't remember that.

We are in total agreement then. The conclusion that Simultaneity is relative i.e. that it is frame dependent is based on circular reasoning.

I will not agree to that.  I've said repeatedly that SoR does not assume SoR.  It follows from different premises.  I agreed that those different premises cannot be proved.

As such, it is an untestable/unfalsifiable prediction/conclusion/hypothesis however you want to frame it.

With that I agree.

I've clarified this above.  Alice represents us trying to determine what kind of Universe she/we live in.

She's going about it all wrong then.

Alice is simply performing an experiment to try and help her determine what kind of universe she/we lives in. From her plausibly actualised observations we can draw conclusions about the universe thst we live in.

How so?  What has Alice ever done that might make you conclude one way or the other?

One can simply drop any assumptions about the Simultaneity of events in a stationary system.

Good start, yes.  You suggested this above, where I replied "Now what?".

The conclusion that simultaneity is relative requires the conclusion to be assumed.

No, it requires the premises leading to that conclusion to be assumed.  Nobody ever assumed RoS.  They assumed something else.  That something else is what we need to drop if we wish to determine what sort of universe we live in (A or R).  To not drop that assumption would indeed be begging a conclusion, even if RoS isn't the assumption being dropped.

The conclusion that it isn't relative simply require us to not make the assumption that it is.

Wrong.  That conclusion also requires you to assume that it isn't relative, not just drop the assumption that it is relative.  You've made a different assumption if you don't do that.
It is the difference between "I don't know" and "I know R is wrong".  Only under the latter assumption allows the conclusion you make above.  You are otherwise assuming the conclusion.

If you want to make a determination between the two, start with "I don't know".

It simply requires us to consider the totality of empirical evidence only and not append any assumptions to that evidence; assumptions that are contradicted by the evidence.

I agree you need to do that, but it is not enough.  It requires more than that.  It in fact requires a falsificaton test, and lacking that, the two views remain just interpretations.