[the_roosh (OP)]

@Halc
My reply exceeds the word limit, so I will distill the debate down to a key point and post it separately. I will post the response to your post in 2/3 posts.

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

So you agree that it is predicted by the interpretation?

OK, so now you only need to show how it is “an actual measurement” actually measured  in the real-world experimental set-up (as represented by the thought experiment). As opposed to being “demanded by the mathematics”. You must demonstrate how the real-world conforms to the mathematics – in this very specific case.

Bearing in mind that the thought experiment represents a plausible, real-world experimental set-up from which we can make inferenes and deducctions about the real-world.

If there is no empirical observation which verifies the prediction or verifies that the “demands” of the mathematics (or rather, the demands of the assumption) are met, then the truth of the prediction/statement about the configuration of the physical system must be assumed.

The conclusion of RoS hangs on the thread of this statement/prediction about the configuration of the physical system. Assuming it to be true, assumes the conclusion of RoS
======================

[the_roosh (OP)]

@Halc - post 1/4

I will be offline for the next 3-4 weeks because I am doing a meditation retreat in Thailand and Malaysia, so you have time to respond to this.

Before signing off [for that time] I want to reiterate that I do appreciate your taking the time to reply, and reply in such detail. Either one of us (me) or both of us will be richer because of it (figuratively, in the sense of acquiring knowledge)
===============

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?

My apologies, I may have overstated the case.
She is performing a procedure from which deductions and inferences can be drawn and applied to the different interpretations.

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.

Agreed, which is why we can treat it as though it has actually happened and draw inferences and deductions from it.

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

I'm talking about the observations Alice must make and the observations she cannot make. We can deduce this from the thought experiment and apply it to a real-world experimental set-up.

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.

The mathematics are the same for the different interpretations. As such, they make truth claims about the configuration of a system. That is, predictions about the configuration of the system can be extracted from the different interpretations.
From the Einsteinian interpretation we can extract a prediction about the configuration of the physical system which says the reading on clock A will be d/c for events B1 and B2 i.e. events B1 and B2 will be simultaneous with the reading d/c on C0 – this statement about the physical system can be extracted from the interpretation.

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.

The position being advanced is that the Simultaneity of events in the stationary system cannot be determined – this fact is derived from the observational evidence, not from an assumption,  so it is not circular.

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.

The Einsteinian interpretation makes a prediction about the configuration of the physical system – the reading on C0 that coincides with B1 and B2 (note, this a claim of simultaneity in the stationary system). Alice's attempt at the synchronization procedure can be seen as a test of this prediction.
From the thought experiment we can draw conclusions about what the actual observations say and what assumptions they support or contradict.

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.

On what basis are you saying that they appear to be simultaneous? On the basis that light signals from both return to Alice/C0 simultaneously? As has been outlined, they would return simultaneously in the case when the clocks are not synchronised either, so this cannot be taken to indicate one or the other.

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.

This is the crux of the issue! How are the events “found to be (not assumed)” simultaneous in the frame i.e. what observation does Alice make that confirms that events B1 an B2 are simultaneous meaning that the clocks are sychronised. What observation does she make that confirms that the demands of the mathematics are fulfilled?

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.

The Einsteinian interpretation says simultaneity is relative. Either way, to satisfy the first part of the conditional – that leads to the conclusion that simultaneity is relative – the simultaneity of events in the stationary frame have to be assumed. IF events are not assumed to be simultaneous, the conclusion that simultaneity is relative cannot be reached.

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.

The question as to what empirical observation can be made to determine that two such events are simultaneous in the physical configuration of the system remains. The answer is that no such observation can be made as a matter of practicality of the real world, but also as a matter of principle according to the foundational assumptions of the Einsteinian interpretation.

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.

You are confusing the idea of deriving something mathematically and deriving something rom observation. The simultaneity of the events that is derived from the mathematics is a prediction. Just as the statement about the configuration of the system - where events B1 and B2 coincide with the reading d/c on C0 - derived from the Einsteinian interpretation, is a prediction (as you’ve stated above). It certainly isn’t derived from observation. The accuracy of the statement – about the physical configuration of the system – made derived from the Einsteinian interpretation must be assumed because it certainly is not observed, in any empirical manner.
Indeed, the foundational assumptions of the theory preclude its observation, in principle. Therein lies the assumption of the conclusion that simultaneity is relative – in the Einsteinian interpretation.
Just to be clear, the alternative interpretation says that the simultaneity of events cannot be determined in the stationary system and so does not rely on circular logic. This conclusion is drived from [plausible/necessary]  observations.

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.

It is also the circularity I am talking about. Alice is performing a valid variation on the prescribed synchronisation procedure. As such, inferences and conclusions can be drawn from it.
She “[concludes] that [the events] are simultaneous in a way meaningful only to that interpretation. Let’s think about that statement. How is it meaningful to that interpretation? All other observers say the events weren’t simultaneous. If this is the case, how can we have an interpretation that says simultaneity is relative? Alice must conclude that events in her frame are simultaneous for this interpretation to be valid. How does she conclude that the events are simultaneous? Not by way of empirical observation – the theory itself precludes it. By mathematics? Empiricism requires that mathematical predictions/calculations be verified by empirical observations (hence the name empiricism). How then does she conclude that the events were simultaneous in such a way that it is meaningful to the interpretation? Well, the interpretation requires the conclusion that events are simultaneous in her frame – bcos we already have the observational evidence to the contrary – so, to give meaning to the interpretation, Alice must assume the conclusion (that the events were simultaneous)

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?

We can simply say that the average [of the two-way] speed of light is c. Or just not make any assumptions about the simultaneity of events.
Either way, we can draw inferences and deductions from the thought experiment, as is.

[the_roosh (OP)]

@Halc - post 2/4

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.
I’m presuming you can see how this means that the two clocks aren’t actually synced.
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.
....
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.
 

Sounds very interesting. Can you recommend a source that shows the peer review of this confirming that it measures the one-way speed of light. I and many others would be very interested in reading it. Until then, I’ll go with the peer reviewed stuff that says it hasn’t been successfully measured.
It is interesting though that you are offering something which measures a different value for the speed off light (close though it may be) and asserting that this different value demonstrates that the one way speed of light is constant.

[the_roosh (OP)]

@Halc - post 3/4

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

A statement about the configuration of the physical system can be derived from the Einsteinian interpretation. This represents a prediction. It is a statement upon which one of its core conclusions rests entirely. It is a statement whose accuracy must be assumed; therefore one of its core conclusions must be assumed.

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.

A more accurate analogy:
If 5 pieces of fruit are apples in one frame, then they are oranges in a relatively moving frame. The observer in the stationary frame cannot see the pieces of fruit – under the foundational assumptions of the interpretation (a glass box with a non-transparent lid, where they can only look down on the box. All relatively moving observers make empirical observations (seeing into the box from the side) that the pieces of fruit in the box are oranges. The observer assumes that the 5 pieces of fruit are apples, therefore fruit is frame dependent.

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.

Not that it is meaningless, just that the simultaneity of two events, in a stationary system, cannot be determined by a comoving observer. So no circular conclusions need be drawn.

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.

We’re checking to see if the reading d/c on C0 coincides with events B1 and B2 i.e. testing to see if B1 and B2 are acctually synchronised in the stationary system – as the conclusion of RoS necessitates. Play around with it and you’ll see why its just the same issue in a different location.

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

My apologies, I probably intended to say that it was self-consistent. It’s validity is dependent on whether an interpretation that assumes its conclusions is more valid than one that doesn’t.

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.

The empirical evidence is that which can be deduced from the thought experiment – which represents a plausible real world experimental set-up, from which we can draw inferences and conclusions – the empirical observations of all other observers.
While it doesn’t contradict the interpretation, it contradicts the assumption upon which the interpretation hangs. The reason it doesn’t contradict the interpretation is because the interpretation assumes the conclusion. Basically, it takes the empirical evidence (of all other observers) and adds the assumption (which is contradicted by the evidence). The interpretation is basically the evidence + the unjustifiable assumption. By way of analogy:

The interpretation represents a map. The plausible real world set-up [as represented by the thought experiment] represents the territory. On the map there is a lake called Loch Ness. “In” the lake there is a picture of a partially submerged creature labelled “the Loch Ness Monster”. The key on the side of the map says that the Locch Ness Monsters presence in the lake must be “established by definition” i.e. it must be assumed that Nessy be in them there waters. The territory might look a lot like the map, but the underwater footage of the lake with no sign of Nessy certainly contradicts the assumption.

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.

Precisely. There is no observation that can be made to “prove” the simulltaneity of the events. That is, there is no empirical observation [that can be made] to verify the prediction/statement of the physical system than can be derived from the Einsteinian interpretation. There is no empirical observation which supports the contention that the clocks on Alice’s spaceship are synchronised, all empirical evidence shows the clocks on the spaceship are not synchronised. The contention that the clocks on board the spaceship are synchronised (from anyone’s perspective) is not supported by empirical observation so it can only be assumed. This contention is the string by which RoS dubiously hangs.

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.

By “putting words in your mouth” I think you will find that I am simply making inferences an deductions about what follows by way of necessity from what you do say.
The signals returning simultaneously to the detector verify that C1 and C2 are in sync in that frame. No they don’t! They verify that the signals return simultaneously to the detector. As has been pointed out, the signals would return simultaneously if the time to C1 and C2 were not the same, as this would be evened out on the return leg.
As you quite rightly state it does not “constitute any sort of verification concerning C0”, as such verification is impossible. Ask yourself, how then can Alice be sure that her calculations (which rest on her assumption) are actually correct, in her frame? How does Alice determine that the clocks are synchronised if it isn’t by way of observation that both events happen “at the same time”. How does she determine that the “demands” made by her mathematics are met by the physical system?
It might be worth pointing out now, too, that her conclusion of length contraction also rests on the assumption that her clocks are synchronised.
She simply cannot make this determination, she must assume it.

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.

It wouldn’t be like you [to be picky]!
To be equally picky, if you read back over where I asked you if you had any objections to the way the thought experiment was formalised, you will see the clock bolted to point B1 has a label B1 one on it while the clock bolted to B2 has a label B2 on it. Given that both clocks remain bolted to their respective spots means that for the purposes of what we are discussing – Alice’s synchronisation procedure in her spaceship – the distinction between points and clocks are immaterial because they remain co-located.
You were seeming to have extreme difficulty seeing how Alice’s synchronisation procedure was a valid variation on Einstein’s synchronisation convention, which is why I labelled the emitter as A and the clocks as B1 and B2. Incidentally, it is also why I introduced the clock at A, which you gave the name C0 to and made the statement about the reading on which coincides with the two events at B1 and at B2 on clocks C1 and C2.

[the_roosh (OP)]

@Halc - post 4/4
===============

Yes to all that, but none of that describes a verification procedure for it.

It would represent a verification procedure; indeed, it represents the only way in which the simultaneity of synchronisation events could actually be verified. That this cannot be verified is the point being made.

Did Einstein put a 3rd clock between the two in his description of the convention to sync the first two?  Don't remember that.

See what I mean about having difficulty with seeing how the thought experiment represents a valid variation on Einstein’s synchronisation procedure. That is why C0 – the name you gave it – was introduced. In Einstein’s convention he has light going from [the clocks at]:
A > B > A
In our thought experiment we have light going from the clocks at:
A > B1 > A
A > B2 > A
Can you now see how it is a valid variation on Einstein’s convention?
Incidentally, I don’t remember Einstein mentioning anything about flying 2 atomic clocks around the world on commercial airliners, but this represents a test of his theory because the prediction can be derived/extracted from the interpretation. Just as the statement/prediction pertaining to the reading on C0 can be derived/extracted.

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.

If there is no empirical observation that the clocks in Alice’s spaceship are synchronised with each other, in her frame of reference, then it can only be assumed to be a valid prediction. Assuming this assumes the conclusion.

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

With that I agree.[/quote]
If you agree that it is untestable, then you agree that it must be assumed. Given that the conclusion of RoS hangs by a string on the idea that the clocks are synchronised, in Alice’s frame, assuming this means that it follows, by way of necessity, that the conclusion of RoS is assumed.

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?

Alice has demonstrated that the idea, that her clocks are synchronised in her frame, is not supported by any empirical evidence so it must therefore be assumed. Indeed, the totality off observational evidence contradicts her assumption by showing that her clocks are not synchroniseed. It therefore shows us that the conclusion that simultaneity is frame dependent i.e. that simultaneity is relative i.e. the conclusion of RoS is propped up solely by circular reasoning i.e. the conclusion is 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.

It requires that the truth of the statement: clocks in the stationary system are synchronised, in that frame, be assumed – because it cannot be verified experimentally. Assuming the validity of this statement means the conclusion of RoS is assumed.

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".

The alternative doesn’t rely on circular reasoning because it makes no statement about the simultaneity of events in the stationary system. It simply says that this cannot be determined – a statement which can be derived from the observational evidence. That is, it starts with “We don’t know if the clocks are synchronised”. No conclusions assumed there.

 

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.

If we consider Alice’s assumption:
The clocks on Alice’s spaceship are synchronised with each other.
What empirical evidence is there to support that assumption? There is no actual evidence to support it.
Consider then, the totality of empirical evidence that does exist, all of which shows that the clocks on Alice’s spaceship are not synchronised. Therefore, the totality of empirical evidence contradicts Alice’s assumption.
At this point, Alice can weigh up the empirical evidence against her assumption. If she wants to stick her fingers in her ears, ignore the totality of empirical evidence that contradicts her assumption, and continue to cling on to her assumption, she can construct a narrative (the Einsteinian interpretation) which says that simultaneity is frame dependent. But, this conclusion rests entirely on her unverified, unsupported assumption. It rests on her assuming it to be true (on her spaceship) in spite of the observational evidence to the contrary, evidence which contradicts her assumption that her clocks, on her spaceship are synchronised. Her interpretation requires her to assume her conclusion.
The evidence represents a falsification of her assumption, but because she employs circular reasoning to construct a narrative, it doesn’t contradict her made up story.

It would be like Alice’s belief that the Flying Spaghetti Monster created the initial conditions of the universe. Then, all empirical evidence demonstrates where the initial conditions of the universe came from and there is no sign of the FSM. If Alice’s thesis says that we must establish by definition that the FSM created the initial conditions i.e. we must assume that the FSM created the initial conditions, then of course she will conclude that the FSM is responsible for the universe in its current configuration (derived from the initial conditions). The empirical observation of a Universe in its current configuration will not contradict her story about the FSM being responsible for the current configuration of the Universe. However, the totality of empirical evidence demonstrating where the initial conditions came from (with no sign of the noodly appendage of the FSM) certainly contradicts her assumption. Richard Dawkin’s might use the term “delusional” to describe Alice’s beliefs.

[Halc]

My apologies, I may have overstated the case.
She is performing a procedure from which deductions and inferences can be drawn and applied to the different interpretations.

None of her deductions and inferences can be applied to other interpretations since she assumed an interpretation in making those deductions and inferences.
What she is doing is assigning an arbitrary coordinate system (an alignment of the four axes of 4D space) to her situation.  For convenience, she aligned the x axis to run between the two clocks she's trying to sync.  She doesn't have to do that, but it makes for far less trigonometry if she does that.  Perhaps you think this is an invalid assignment, and there is an objective X axis somewhere, waiting for some experiment to determine it.  An absolutist should probably assert that to be consistent.  Anyway, Alice aligns that axis with her clocks, and also aligns the t axis parallel to the worldlines of those two clocks, and her only claim is that the two sync events happen to have coordinates with the same value for t (and y and z while we're at it).
It's a pretty lightweight claim actually.  Bob does not disagree with her claim.  You do, but perhaps on grounds that Alice is not within her rights to align the coordinate system like that.  PoR says no empirical prediction is dependent on this choice of orientation.

Yes, if her task is to determine which interpretation represents reality, then she cannot take her assumptions (that it is valid to orient the abstract coordinate system to her convenience) in there with her.  But without those assumptions, I'm not sure what her actions are accomplishing.  Certainly not the syncing of her clocks.  There is no interpretation-independent procedure for doing that.

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.

Agreed, which is why we can treat it as though it has actually happened and draw inferences and deductions from it.

You can treat it as though it has actually happened.  But yes, you cannot draw interpretation independent inferences from it IF those inferences where made from one interpretation or another.  That's been your problem all along.  You made an interpretational assumption and you're repeatedly trying to apply your inferences to what Alice has been doing under a different interpretation.  All your conflicts come from doing this.
If your goal is to find the correct interpretation, drop all the begging assumptions and just look at the facts.  Alice has not been doing that, which is why I say she is going about your task all wrong.  She makes begging assumptions about her interpretation, so she's only showing her interpretation to be self consistent, but she's not asserting any sort of interpretation independent truth like some "pair of clocks are in fact in sync", which would actually be meaningless words without an interpretation.  How can meaningless words be a truth statement?

The mathematics are the same for the different interpretations.

The mathematics is very much not, but I don't see how this is relevant to the comment above.

As such, they make truth claims about the configuration of a system.
That is, predictions about the configuration of the system can be extracted from the different interpretations.

Does Alice make a truth claim?  She says that if she draws a line through the two sync events B1 and B2, that the coordinates of those two events along any second line drawn perpendicular to this first line will be the same.  That includes all three of the remaining axes.  I suppose that is a truth claim, and since it is an entirely abstract geometric one, it seems hard to contest the truth of it.  Perhaps you think she's making a different truth claim than this one, but doing so risks the committing of the strawman fallacy.
So what truth claim (something other than an empirical prediction) do you think Alice is making, or more exactly, what truth claim to you think I'm making about the situation with Alice?

Truth claims are not predictions since there is no way to directly verify them.

I think there are ways to verify the truth claim stated just above.  Provide a counterexample if you disagree with it.

  So for instance, Alice claims that events B1 and B2 have the same t,y,z coordinates in the coordinate system she has chosen, but she subsequently needs to use that coordinate system to verify the claim using some prediction related to that coordinate system.  She has not claimed that they have the same t coordinate given an alternate orientation of that t axis.  If her task is to determine if there is one correct orientation for the coordinate system, her claims seem to be irrelevant to that task.  PoR says any orientation can be used without affecting predictions made using that orientation.

From the Einsteinian interpretation we can extract a prediction about the configuration of the physical system which says the reading on clock A will be d/c for events B1 and B2 i.e. events B1 and B2 will be simultaneous with the reading d/c on C0 – this statement about the physical system can be extracted from the interpretation.

This is not a prediction, merely a truth claim, and a meaningless one without a frame reference.  If we're talking about her frame, then this would be a meaningful truth claim, but still not a prediction.

A lot of the miscomunication between us seems to be your usage of 'prediction' to mean 'interpretational dependent of state of the system' or worse 'truth claim'.  Prediction means that one will observer X if the test is performed.  A prediction is not interpretation dependent, which is why predictions are how valid theories are distinguished from invalid ones.

One cannot observe simultaneity, so it isn't a prediction.  One can, on the other hand. observe signals arriving at a measurement device in a certain order.  That's a prediction.  I refuse to label a statement of state to be a prediction.  If the word means something else to you, then find at different word that means an 'anticipated empirical observation'.

You talk all the time about predictions that cannot be verified.  I don't call those predictions, just descriptions of state.  Alice claims (not predicts or assumes) that her clocks are synced in her frame (more precisely worded about when described as an orientation of an abstract coordinate system to assign one spatial axis so both sync events pass through it), and neither Bob nor you (if you know your physics) should disagree with this.  That claim does not contradict her clocks being not synced in either Bob's frame or yours, so no contradiction has been demonstrated.  If we have such a contradiction, then we can devise an experiment that differentiates between the two cases and proposes an actual useful prediction.

Why is it that all these crank threads end up in arguments over a redefinition of standard terms?

The position being advanced is that the Simultaneity of events in the stationary system cannot be determined – this fact is derived from the observational evidence, not from an assumption,  so it is not circular.

Do you mean that the simultaneity of events relative to the arbitrarily designated system with Alice stationary in it?  If so, I disagree since Alice has shown exactly that.
If you mean a non-relative statement above, or you are claiming that Alice's system is not stationary, then 1, you are using interpretational dependent language (making assumptions just as you claim Alice is), and 2, I agree that such a determination cannot be made.

This is the crux of the issue! How are the events “found to be (not assumed)” simultaneous in the frame i.e. what observation does Alice make that confirms that events B1 an B2 are simultaneous meaning that the clocks are sychronised.

The setup assures the sync in frame A, even without observation. An observation of the simultaneous return signal serves as a redundant confirmation of this. Come on, you know these answers. Why must I endlessly repeat them?

What observation does she make that confirms that the demands of the mathematics are fulfilled?

All the setup observations need to be made as well: that the clocks are indeed placed equidistant from the middle point for instance. That observation of the setup is only needed for Alice to know the clocks are synced. The clocks are synced in that frame whether or not those observations are made. The setup is enough.
Your wording seemed to focus more on epistemology: how Alice might know/confirm the sync, rather than how the sync is assured given the stated setup.

The Einsteinian interpretation says simultaneity is relative.

It demonstrates that, not just assumes it.  Using 'says' doesn't make that very clear. It is an interpretational statement, yes. It isn't true in an absolute interpretation of relativity theory, not because the physics is different, but the language is different. Since the physics is the same, there can be no predictions to help Alice with her task of determining the correct interpretation.

IF events are not assumed to be simultaneous, the conclusion that simultaneity is relative cannot be reached.

Trying to parse this one, and failed.  Are you claiming that RoS implies that all events are simultaneous?  Probably not, but that's how this reads.

The question as to what empirical observation can be made to determine that two such events are simultaneous in the physical configuration of the system remains.

Nope.  Those words have no interpretation-independent meaning.  If you're going to use those words, you need to choose (assume if you will) an interpretation.  Only then can some empirical observation be made to make such a determination.
I'm asking you to reword the question in some way so it has meaning.  State the interpretation you assume, or state the question in terms that are not dependent on them.

Essentially, you're tasked with how one can determine the angle between a given line and another unspecified one.  One interpretation of the task is that one is free to specify it, and the other interpretation is that one cannot make the determination because the lack of a way to know where the 2nd line is.  Alice assuming the first answer allows a way to actually determine (not assume) the angle (using a protractor maybe), and you (assuming the second answer) say that usage of the protractor is invalid because the protractor requires both lines to be measurable, not just one plus an arbitrarily selected third line.

In fact there is no conflict.  You're both making assumptions, but different ones.  Nobody is just working from the facts, which happens to consist of a task description lacking clear meaning.

You are confusing the idea of deriving something mathematically and deriving something from observation.

No I'm not.  It's all quite mathematical since we're discussing synchronization, something that only has abstract meaning.  Synchronization of separated clocks cannot be observed.  What can be observed is perhaps the time displayed on a clock or several.   If 'synced' was defined as two clocks reading the same value at some observation event, then synchronization would be an observable (and event dependent) thing. Well, it isn't defined that way by either interpretation.  Both interpretations have an abstract definition of it, which is necessary for any non-local definition of something.
An absolute interpretation might contain a premise that there is one abstract inertial frame which corresponds physically to the physical universe in a way that the other abstract frames do not, making it a preferred intertial frame.  Most abstract interpretations do not attempt this, and instead use a non-inertial description of 3D space, or maybe a non-inertial foliation of 4D spacetime.  I actually don't know where your favored interpretation fits into all that.  The sync procedure depends on those assumed premises.

The simultaneity of the events that is derived from the mathematics is a prediction. Just as the statement about the configuration of the system - where events B1 and B2 coincide with the reading d/c on C0 - derived from the Einsteinian interpretation, is a prediction (as you’ve stated above).

I've stated no such thing. I said quite clearly that none of these things constitute predictions.  A prediction is a much stronger claim than any of that.

It certainly isn’t derived from observation. The accuracy of the statement – about the physical configuration of the system – made derived from the Einsteinian interpretation must be assumed because it certainly is not observed, in any empirical manner.

Which is why it isn't a prediction, yes.

Just to be clear, the alternative interpretation says that the simultaneity of events cannot be determined in the stationary system and so does not rely on circular logic.

The alternative interpretation assumes an interpretation, so it is circular in the same way as you use the term.  If an interpretation cannot assume itself, then your statement above carries no meaning.
The relative interpretation did not say that the two events were simultaneous. That's not what was determined. So the statement above is both begging a different meaning of the terms, and also ascribing strawman claims to the relative interpretation.

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.

It is also the circularity I am talking about. Alice is performing a valid variation on the prescribed synchronisation procedure. As such, inferences and conclusions can be drawn from it.
She “[concludes] that [the events] are simultaneous in a way meaningful only to that interpretation. Let’s think about that statement. How is it meaningful to that interpretation? All other observers say the events weren’t simultaneous.

That statement isn't meaningful under the interpretation. In fact, all other observers completely agree with Alice's statement:  The two events are simultaneous relative to her frame.
Kindly defend your assertion that they disagree with this, or that Alice is claiming something else.  Otherwise it's just the same old strawman claim.

Alice must conclude that events in her frame are simultaneous for this interpretation to be valid.

That said events are simultaneous in her frame.  Very different meaning.  I'm being entirely precise lest you quote me on agreeing with a statement that is misleading.
Your wording implies that events in some frame are simultaneous , and since all events are in all frames, that reduces to these events just being simultaneous, which isn't claimed at all.  The simultaneity is dependent on the frame, but there is no frame dependency on the presence of the events.

How does she conclude that the events are simultaneous? Not by way of empirical observation – the theory itself precludes it.

It does not.  You're begging a different interpretation with that statement.

Empiricism requires that mathematical predictions/calculations be verified by empirical observations (hence the name empiricism). How then does she conclude that the events were simultaneous in such a way that it is meaningful to the interpretation?

I never claimed empiricism.  She needs not do any verification at all for the clocks to be synced in her frame, so I guess she's not an empiricist.  If the setup is done correctly, that's all that is needed.  If Alice doesn't trust the setup, then she can't really trust the verification either.  Maybe somebody put mirrors and such in places that changed the path lengths and the setup isn't really as you described it in the OP.  In that case, Alice has been fooled.

I said it was redundant, so it can be done without the emitter and only the verification step if you like.  Both clocks just start at random times and send a signal to Alice when this happens.  If Alice, equidistant, sees those signals at the same time, the clocks are now verified synced, by chance instead of by design.

[An assumption must be made that] events are simultaneous in her frame – bcos we already have the observational evidence to the contrary

You never identify this 'contrary evidence', so pony up or shut up about it already.  Bob has no such evidence, nor does anybody's bodycam, so does it come from some other source?

So we drop all these assumptions. Now what? In the absence of such assumptions, where do we go?

We can simply say that the average [of the two-way] speed of light is c.

I think people in the 19th century attempted to test that and it was falsified.  Remember my example with the canoe on the creek?  It has an average speed of 1, despite the current in the creek, but the round trip time for the canoe is empirically dependent on the current of the water, and the round trip time for light is not empirically dependent on the reference frame represented by the creek.

Now it turns out that the two way speed of light does average to c and the issue above was explained by time/length contraction, unknown effects back in the 19th century.  So are we allowed to assume time and length contraction, or are we trying to derive everything from scratch?  Let's make the assumptions since both our interpretations support it.  I will accept the premise.

Or just not make any assumptions about the simultaneity of events.

Since such statements are interpretation dependent, we have to of course.  One defines it as a 2-way relation and the other as a 3-way relation.

What about terms like distance, location, and speed/velocity?  Those are interpretation dependent (all being properties in one and relations in the other).  Care must be taken when using such terms.

Either way, we can draw inferences and deductions from the thought experiment, as is.

Can we?  We've left little language in common to discuss what Alice is doing.

[Halc]

Sounds very interesting. Can you recommend a source that shows the peer review of this confirming that it measures the one-way speed of light.

I can find no such review.  Olaus Roemer, 1676.  A fairly accurate measurement was first taken, long before any 2-way method was attempted.  Do you contest that it was a 1-way experiment?  Do you suggest that since it wasn't two way, that the measurement was a guess?
It can still be performed today, and with more accurate instruments.

I and many others would be very interested in reading it. Until then, I’ll go with the peer reviewed stuff that says it hasn’t been successfully measured.

Ah, I see.  The measurement for some reason threatens your claim, thus it needs to be discarded.

It is interesting though that you are offering something which measures a different value for the speed off light (close though it may be) and asserting that this different value demonstrates that the one way speed of light is constant.

I don't thing the initial measurement of any value (say distance to the sun as a random example) was initially measured to the same precision as in subsequent refinements.

It is more interesting that you're challenging the result of the experiment.  The relative interpretation says the speed of light actually is frame independent, and thus c, one way, in any direction.  Yours apparently does not.  If this experiment (given perfect instruments) should yield something other than c, then you have your empirical distinction, and one or the other interpretation could be falsified.  Are you claiming that?  The experiment was certainly repeated (lacking a better way to go about it at the time), and in opposite directions.  They would have noticed if the value was consistently more one way than the opposite way.

If you're not claiming an empirical difference in the measurement, then you compulsion to deny of the validity of the one-way experiment demonstrates your biases taking a higher priority than fact.

Hey, I now have my empirical test for the ignorant/troll interpretation of these posts.

[Halc]

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

A statement about the configuration of the physical system can be derived from the Einsteinian interpretation. This represents a prediction.

That's the metaphysical definition, yes.
This is a science forum and I use the empirical definition of 'prediction'.  Post on a philosophy forum if you want to debate metaphysical truths.

It is a statement upon which one of its core conclusions rests entirely. It is a statement whose accuracy must be assumed; therefore one of its core conclusions must be assumed.

Agree, but none of this makes it an empirical prediction.

A more accurate analogy:
If 5 pieces of fruit are apples in one frame, then they are oranges in a relatively moving frame. The observer in the stationary frame cannot see the pieces of fruit – under the foundational assumptions of the interpretation (a glass box with a non-transparent lid, where they can only look down on the box. All relatively moving observers make empirical observations (seeing into the box from the side) that the pieces of fruit in the box are oranges. The observer assumes that the 5 pieces of fruit are apples, therefore fruit is frame dependent.

OK, the fruit is frame dependent. If that's the foundational assumption, nobody has any empirical evidence to contradict it.  The observer assumes the interpretation, but given that, he knows the fruit is apples because he's in the frame where it's apples. That part is not an additional assumption.

This scenario is not unlike direct idealism where the moon exists only when somebody is looking at it.

We’re checking to see if the reading d/c on C0 coincides with events B1 and B2 i.e. testing to see if B1 and B2 are acctually synchronised in the stationary system

The i.e. makes no sense.  C0 plays no role in the verification that C1 and C2 are synced.  It is just a 3rd clock that you brought for Alice to make additional observations.

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

My apologies, I probably intended to say that it was self-consistent.

How can it be self consistent but not valid?  What do the two mean to youterms ?

It’s validity is dependent on whether an interpretation that assumes its conclusions is more valid than one that doesn’t.

Ah, I see.  Relativity doesn't assume RoS.  At no point is it listed as a premise or is any conclusion based on it before it is demonstrated (and it is demonstrated with a simple example, so like, a couple pages if Einstein is wordy in his examples).

Please don't make statements like this without referencing at least one piece of evidence that contradicts what the interpretation says should be observed.

The empirical evidence is that which can be deduced from the thought experiment – which represents a plausible real world experimental set-up, from which we can draw inferences and conclusions – the empirical observations of all other observers.
While it doesn’t contradict the interpretation, it contradicts the assumption upon which the interpretation hangs.

Hmm... Neither the specific observation nor the contradiction is identified.  You just keep asserting that there is one.  Thought so.

The interpretation represents a map. The plausible real world set-up [as represented by the thought experiment] represents the territory. On the map there is a lake called Loch Ness. “In” the lake there is a picture of a partially submerged creature labelled “the Loch Ness Monster”. The key on the side of the map says that the Locch Ness Monsters presence in the lake must be “established by definition” i.e. it must be assumed that Nessy be in them there waters. The territory might look a lot like the map, but the underwater footage of the lake with no sign of Nessy certainly contradicts the assumption.

Two mistakes.  1) The monster is an assumption, not a conclusion. If it was demonstrated given different assumptions, then the interpretation doesn't assume that conclusion. 2) Absence of evidence is not evidence of absence. No actual contradiction was demonstrated  Oh yea, 3) you personal feeling of implausibility is a good reason to prefer a different interpretation, but it isn't evidence of anything.

There is no empirical observation [that can be made] to verify the prediction/statement of the physical system than can be derived from the Einsteinian interpretation.

True of any interpretation, by definition of the word 'interpretation'.  You didn't answer the question I asked.

There is no empirical observation which supports the contention that the clocks on Alice’s spaceship are synchronised, all empirical evidence shows the clocks on the spaceship are not synchronised.

You have a test for the latter claim?  Alice could use it to falsifiy one or the other interpretation.  If you don't, then it's just another empty assertion.  You have to stop doing those.  BTW, I agree with the first statement (the part before the comma that should have been a semicolen).

The contention that the clocks on board the spaceship are synchronised (from anyone’s perspective) is not supported by empirical observation so it can only be assumed.

They're synced relative to a frame.  They're synced relative to Alice's frame even from Bob's perspective, so it isn't specific to a perspective, despite the usage of that wording by some people to mean a frame reference.
The interpretation is indeed assumed in that statement, as you assume a different interpretation when making your alternate assertions.

The signals returning simultaneously to the detector verify that C1 and C2 are in sync in that frame. No they don’t! They verify that the signals return simultaneously to the detector. As has been pointed out, the signals would return simultaneously if the time to C1 and C2 were not the same, as this would be evened out on the return leg.

And as has been pointed out (by you), if the time to B1 and B2 from A were not the same, then the signals would not arrive back at A at the same time.  Since the emitter and detector are at A and the clocks at the B locations in that frame, and since the time from A to B is the same as B to A by definition, the verification is valid.

As you quite rightly state it does not “constitute any sort of verification concerning C0”, as such verification is impossible.

It's entirely possible to verify some things concerning C0.  I just said the two reflected signals are not involved in that verification.

Ask yourself, how then can Alice be sure that her calculations (which rest on her assumption) are actually correct, in her frame?

We'd have to assume she's capable of mathematics, and that stuff like 2+2=4 is not a frame dependent fact.  Are we casting doubt on these things now?

How does Alice determine that the clocks are synchronised if it isn’t by way of observation that both events happen “at the same time”. How does she determine that the “demands” made by her mathematics are met by the physical system?

See prior answers to this endlessly repeated question.

It might be worth pointing out now, too, that her conclusion of length contraction also rests on the assumption that her clocks are synchronised.

Does your interpretation not include length contraction?  For that matter, how does a conclusion of length contraction follow from a determination of two clocks being synchronized?  What exactly is assumed to contracted in this example?

Your claims get taller and taller..

Given that both clocks remain bolted to their respective spots means that for the purposes of what we are discussing – Alice’s synchronisation procedure in her spaceship – the distinction between points and clocks are immaterial because they remain co-located.

Only in the frame of the ship.  So in Bob's frame, C1 is not at any one location.
It is because of Bob that I carefully distinguish between B1 and C1.

[Halc]

See what I mean about having difficulty with seeing how the thought experiment represents a valid variation on Einstein’s synchronisation procedure. That is why C0 – the name you gave it – was introduced. In Einstein’s convention he has light going from [the clocks at]:
A > B > A

Yes, and he is giving a definition of simultaneity between clocks at A and B, using a different method than putting anything equidistant between them.

His definition provides a direct way to verify that two clocks at points A and B are in sync.  Send a signal from A at t1 (as measured on the clock at A).  When the signal arrives at B, the signal is reflected at time t2 (as measured on the clock at B).  The signal is then received back at A at time t3 on the clock at A.
If t2-t1 = t3-t2, the clocks are by definition in sync.  That method works with any interpretation.  It is frame dependent only because 'location' (what A and B are) is a frame dependent concept, so the frame dependence concerns the location, but not the sync test for the clocks.

I do believe that your interpretation also accepts this definition of simultaneous.  Your interpretation simply defines 'location' differently (as a property of an object, not a relation).

Anyway, we were talking about names of things.  Einstein had A and B instead of B1 and B2.  Yes, we changed the names quite a bit.  I cannot find the sync procedure in Einstein's stuff.  I find the references to the points A and B and a way to determine if clocks at those points are simultaneous, but I can't find the experiment that Alice is doing.

In our thought experiment we have light going from the clocks at:
A > B1 > A
A > B2 > A

From/To A, yes, but the clock there was not referenced.  It's from emitter at A, and to observer at A.

Can you now see how it is a valid variation on Einstein’s convention?

Clocks at A and B1 (or B2) are not claimed to be in sync.  It is a valid variation to get clocks at B1 and B2 in sync, yes.  Did I say otherwise?  Notice that I say clock at B (as does Einstein), not clock C.  It needs to be established that it is at location B1 and B2 (or Einstein's A and B) for the statement to be true.  The definition of simultaneous you quote requires this.

Incidentally, I don’t remember Einstein mentioning anything about flying 2 atomic clocks around the world on commercial airliners, but this represents a test of his theory because the prediction can be derived/extracted from the interpretation. Just as the statement/prediction pertaining to the reading on C0 can be derived/extracted.

Agree.  I derived what it says.  That clock is by definition not in sync with the other two.  If you subtracted d/c from what it says (fall behind, not spring ahead), Alice could verify that it is now in sync with the other two, and do so without moving.  I had her moving to a midpoint and taking a photo from there.  That was a needlessly complicated way to go about it.  Just use the definition.

I've said repeatedly that SoR does not assume SoR.  It follows from different premises.

If there is no empirical observation that the clocks in Alice’s spaceship are synchronised with each other, in her frame of reference

There is an empirical observation.  Alice can use the definition and have light go between the two clocks if you like.  So glad you agree that Alice has determined this.
No idea how this is a relevant reply to my comment about RoS assuming RoS. Your reply is a distraction, meaning you have no evidence for your claim.  It is in fact trivially established from a premise of light speed being constant in any frame.  No clocks are involved in the demonstration.

Given that the conclusion of RoS hangs by a string on the idea that the clocks are synchronised

But I don't give that at all.  It hangs on constant light speed.  No mention of clocks is necessary to show it.  You're making up strawman arguments.  Are you finding these arguments on your denial sites (that you call 'peer review').  Peer review means the peers of the person (like Roemer for instance) putting out new science, not your peers.

Roemer's peers very much approved of his methods, else he'd not be in the history books as the one who first measured light speed.  So it appears that you cannot comment on that experiment because you cannot think for yourself.  You need to find a denial site where your peers do the work for you so you can spout their arguments here, not your own.  Further evidence that you can't think for yourself is that you have no comment when I point out the fallacy of your arguments.  Instead of responding as to how my arguments are wrong, you just repeat the same fallacious lines over an over again, because responses to my posts are not included in the sites from which you get all your material.
I have not eliminated troll either.  The two are not mutually exclusive.

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

Alice has demonstrated that the idea, that her clocks are synchronised in her frame, is not supported by any empirical evidence so it must therefore be assumed.

She can follow the very definition of synchronized, so this is wrong.  Again, you have no response of your own to this, so you just repeat this statement.  I doubt your peers actually said that since they would not have worded it that way.  Alice very much has empirical evidence of the way you word it there.

Your argument falls apart since you have no response to mine except to repeat these easily disproved assertions.

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

The alternative doesn’t rely on circular reasoning because it makes no statement about the simultaneity of events in the stationary system.

It assumes there is such a concept as a stationary system.  Drop that if you want to distinguish between interpretations.

It simply says that this cannot be determined

That's an interpretation specific conclusion. If you assert that, you are assuming your conclusions. Drop that as well.
Say we don't know if it can be determined.

If we consider Alice’s assumption:
The clocks on Alice’s spaceship are synchronised with each other.

If her goal is to find the correct interpretation, then she has not assumed one.  She's done  a procedure that does not meet Einstein's definition of simultaneous, so such a determination has not been made.

What empirical evidence is there to support that assumption? There is no actual evidence to support it.

You're the one making assumptions.  Alice has no idea if her clocks are synced.  She doesn't care actually.  She's there to determine which interpretation is correct, and here she is doing this procedure that doesn't help.  She has no plan actually.

Maybe she should do the light speed measurement using a 1-way experiment as Roemer did 350 years ago.  The R interpretation says that it should measure exactly c, and you say it should measure some number that by chance is not likely to be c.  That's a distinction.  Why don't we have Alice do that?  I described the setup.  Alice measures c.  TaDaaaa....  A is wrong.  R is correct.  We can do it several times in different frames and directions in case the first measurement was a chance fluke.

Show me you know how to think and don't need to rely on your peers (or just flat out denial) to respond to this.  We can do it with nice accurate atomic clocks and a tape measure that's as accurate as we want.  It's a thought experiment.  Budget is no barrier.  The real test was not a thought experiment, but the best long term clock they had at the time was a sundial.  The pendulum clock had been invented about 7 years prior, and this invention, coupled with the sun, is probably why that discovery was made at that time.

[the_roosh (OP)]

Again, we have to bring things right back to basics before we can proceed any further, and I believe this is the sticking point.

Synchronization of separated clocks cannot be observed.

This is exactly the point!

If Alice cannot observe that the clocks in her inertial frame are synchronised then she can only assume that they are. And, it doesn't matter if she does this in an absolute manner or a frame dependent manner. If she cannot observe then she can only assume, in both contexts.

Empirically speaking, that is.

You are confusing the idea of deriving something mathematically and deriving something from observation.

No I'm not.  It's all quite mathematical since we're discussing synchronization, something that only has abstract meaning.

The synchronisation procedure is a real-world, physical process. It is not "all quite mathematical", it is not simply a mathematical procedure. Yes, mathematics are abstract and the definition of synchronisation under a mathematical co-ordinate frame is an abstraction, but there's a reason why empirical tests are required to verify mathematical predictions. To check the validity of the abstract mathematics.

The abstract mathematics doesn't necessarily imply that the clocks are synchronised. The Lorentz-Poincare interpretation also employs the Lorentz transformation between the relatively moving reference frames, but the clocks in those reference frames are not synchronised, under that interpretation. Only the Einsteinian interpretation assumes this on the basis of establishing synchronisation by definition that is - clearly and unequivocaly - by assuming it.

Einstein even talks about what we mean by the "time" of an event. He says that we are always talking about the simultaneity of events as in when a train arrives at a station, it is simultaneous with the reading with the position off the hands on the watch.

Disclaimer: You will have trouble parsing the following, but try reading it a few times and some times without the square brackets. Its purpose is to highlight that clock synchronisation is a real-world, physical, not-mathematical procedure.

So, from the abstract, mathematical, stationary, co-ordinate reference frame that Alice chooses to employ, we can derive a prediction about the [real-world, physical, not-mathematical] clock synchrnoisation procedure that Alice carries out onboard her physical, not mathematical spaceship, which constitutes her "stationary system". This mathematical description says that the reading on the [real-world, physical, not-mathematical] clock, which we have labelled as "A", that the reading on this clock that corresponds to the [real-world, physical, not-mathematical] photon making physical - not mathematical - contact with the [real-world, physical, not-mathematical] clocks [which we have labelled] B1 and B2 (because they are nailed to the floor at points B1 and B2, in her "stationary system"/in her reference frame), that the reading on this clock will correspond to a value of d/c and will be the same for both [real-world, physical, not-mathematical] events.

As you have clearly stated, "synchronization of separated clocks cannot be observed". If it cannot be observed but Alice maintains that they are synchronised in any way, shape, form, context, frame, in any way whatsoever, then she does this purely by assuming it to be the case. If she cannot observe it then she can only assume it, she can only establish it by definition.

Again, you are confusing the map with the territory. The key on your map says the Loch Ness Monster must be assumed to be in the lake and you are concluding that the Loch Ness Monster is in the lake. That is, empirically speaking, ciruclar reasoning.

EDIT:
you seem to be under the impression that I'm an absolutist, despite you remarking earlier in the discussion that I wasn't - remember, I'm saying that there is no absolute time. It's understandable given that I am referencing Lorentz-Poincare theory but that is simply to demonstrate the assumption inherent in the Einsteinian interpretation.

If we can get you past the basic point of empiricism then I can outline the rest of the interpretation and demonstrate how no absolute reference frame is necessary.

[Halc]

Hey roosh, how was the trip?

Again, we have to bring things right back to basics before we can proceed any further, and I believe this is the sticking point.

Synchronization of separated clocks cannot be observed.

This is exactly the point!

If Alice cannot observe that the clocks in her inertial frame are synchronised

I didn't say 'in her inertial frame'.  Given an abstract selection of a coordinate system, the synchronization of two clocks can very much be measured/observed, per Einstein's definition of synchronized clocks.  That procedure even works in your interpretation.
You send a pulse at time T1a from a clock at one location and measure the time T1b on the clock at the distant location when that pulse is received. Subtracting the two gives duration D1.  You do the same in the reverse direction to get D2.  Iff D1 and D2 are equal, the clocks at those two locations are in sync in the selected frame by definition.

Since the frame selection is an arbitrary selection of abstract coordinate systems, the statement that two clocks are in sync in that frame is a purely abstract statement.  Perhaps your disconnect is along those lines, like Alice is making some sort of metaphysical claim when she runs her verification procedure.  She's not.

You are confusing the idea of deriving something mathematically and deriving something from observation.

No I'm not.  It's all quite mathematical since we're discussing synchronization, something that only has abstract meaning.

The synchronisation procedure is a real-world, physical process. It is not simply a mathematical procedure.

It requires a selection of a coordinate system, which makes the result of the real world procedure only as physical as that selection, which is to say it isn't.

Yes, mathematics are abstract and the definition of synchronisation under a mathematical co-ordinate frame is an abstraction

But that abstraction is all that Alice is claiming.

but there's a reason why empirical tests are required to verify mathematical predictions. To check the validity of the abstract mathematics.

Disagree.  I can think of no physical procedure that is used to verify a purely mathematical concept.  One can verify the prediction that a sync procedure (done from the midpoint say) indeed produces a valid sync by doing the verification by definition (which is not done at the midpoint), but that is a test that the physical behavior matches the mathematical model, not a verification of the mathematical definition.

The abstract mathematics doesn't necessarily imply that the clocks are synchronised.

No frame reference, so I don't disagree with this.

The Lorentz-Poincare interpretation also employs the Lorentz transformation between the relatively moving reference frames, but the clocks in those reference frames are not synchronised, under that interpretation.

By definition, yes.  Still not disagreeing.

So, from the abstract, mathematical, stationary, co-ordinate reference frame that Alice chooses to employ

It isn't stationary.  It is an arbitrary frame.  The fact that you found one mention of the word 'stationary' as a simple designation in Einstein's work is not an assertion that the frame is a preferred one.  I continue to harp on this because you're using the concept to give metaphysical meaning to something that isn't a metaphysical statement.

we can derive a prediction about the [real-world, physical, not-mathematical] clock synchrnoisation procedure that Alice carries out onboard her physical, not mathematical spaceship, which constitutes her "stationary system". This mathematical description says that the reading on the [real-world, physical, not-mathematical] clock, which we have labelled as "A", that the reading on this clock that corresponds to the [real-world, physical, not-mathematical] photon making physical - not mathematical - contact with the [real-world, physical, not-mathematical] clocks [which we have labelled] B1 and B2 (because they are nailed to the floor at points B1 and B2, in her "stationary system"/in her reference frame), that the reading on this clock will correspond to a value of d/c and will be the same for both [real-world, physical, not-mathematical] events.

I didn't get the last bit: "will be the same for both events".  What events?  I assume the zeroing events of the clocks at B1 and B2, in which case I agree that the reading of d/c on clock at A would be simultaneous with those two zeroing events in the frame where all the clocks involved remain at their respective locations.  I would not agree to the ambiguously worded statement of something being the same for both events.

If she cannot observe it then she can only assume it, she can only establish it by definition.

Establishing it by definition is not assuming it.  She's quite capable of applying the definition and verifying it.  She has not done so in the procedure you describe above.  The definition doesn't involve a 3rd location.

[the_roosh (OP)]

Hey roosh, how was the trip?

It was good, thanks  . Just left the monastery today and am heading to Malaysia in the next couple of days for another 2 week retreat. I had time to flesh out a different part off the argument I'm making, which we'll hopefully get to 

I didn't say 'in her inertial frame'.

This is probably a big part of the issue. I am trying to clarify my thinking but I am using terms imprecisely/interchangably, which is probably leading to us talking past each other in some cases. I'm having a similar discussion on another forum with people who I'e debated against before, who are probably used to me doing this, so haven't been pulling me up on it, because they understand the point I am trying to make. So, I haven't learned to be more precise. So apologies if that is the case.

Given an abstract selection of a coordinate system, the synchronization of two clocks can very much be measured/observed, per Einstein's definition of synchronized clocks.  That procedure even works in your interpretation.
You send a pulse at time T1a from a clock at one location and measure the time T1b on the clock at the distant location when that pulse is received. Subtracting the two gives duration D1.  You do the same in the reverse direction to get D2.  Iff D1 and D2 are equal, the clocks at those two locations are in sync in the selected frame by definition.

Apologies, can we walk thru this bcos I'm not fully clear on your reasoning here. I'll outline my understanding, sticking as closely to the Einsteinian synchronisation procedure as I can, and you can highlight where I'm going wrong - if that suits?

You have the 2 clocks as you outline there. Let's call the clocks C1 and C2 for convenience. At time T0 on C1, you send the pulse to C2, which zeros C2. How do you measure the duration of the journey from C1 to C2?

or, do you mean:
that both clocks are started independently, not synchronously and at the random time T1a [on C1], a pulse is sent from one clock to the other clock [C2] which registers the time of T1b. Subtract the 2 values to get D1. This would give us a random value not necessarily the duration of the journey from C1 to C2 - because we don't know if the clocks were started simultaneously. Lets, for arguments sake, say that the value it gives us is 2 units of time.

Then, at a random time T2b a pulse is sent from C2 to C1. The 2 values are subtracted to give D2. Let's imagine for a second though, that C2 was started 1 unit of time before C1. Subtracting the two values will give us 0 (assuming the same journey time).

Since the frame selection is an arbitrary selection of abstract coordinate systems, the statement that two clocks are in sync in that frame is a purely abstract statement.  Perhaps your disconnect is along those lines, like Alice is making some sort of metaphysical claim when she runs her verification procedure.  She's not.

This is where the disconnect is, I think. We don't need to assume that she is making a metaphysical claim - even though such a claim has pretty drastic metaphysical implications pertaining the the physical structure of the universe, stemming from that claim.

We need only talk about the physical system in which Alice finds herself, and the physical synchronisation procedure that she carries out. We're talking about empirical verification of Alice's claims. In this sense, her statement that the two clocks are in sync is not a purely abstract statement. It's a statement about the physical configuration of a real-world inertial system.

Yes, mathematics are abstract and the definition of synchronisation under a mathematical co-ordinate frame is an abstraction

But that abstraction is all that Alice is claiming.

And what we're doing is seeing how well Alice's abstraction maps onto the physical world. We're checking to see if her abstraction can be verified empirically.

Given Alice's abstraction we are free to derive/deduce other claims about the configuration of her physical system that follow as a necessity from her abstraction. Alice may not have expreessly stated these from the outset, as she may have been unaware of them, but as with any physicl theory/interpretation, we can see what it logically necessitates and go about testing that, empirically. In doing so, we can see that her abstraction includes a logically necessary statement about the simultaneity of clock synchronisation events and their coincidence with the reading on a clock located midway between them. This is simply a statement about the configuration of the physical system that we can deduce from Alice's abstraction and which gives us further insight into her interpretation.

As we have agreed, this part of Alice's abstraction cannot be verified empirically, that is, we cannot determine, by way of observation, that Alice's abstraction is an accurate representatation of the physical world. For Alice to maintain her belief in this abstraction she does so, not on the basis of empirical observation, she does so only by way of assumption.

In this sense, Alice's abstraction (co-ordinate reference frame) is the "map" and her physical, inertial frame is the territory. Her map includes claims about the territory that are not to be found anywhere in the territory.

Disagree.  I can think of no physical procedure that is used to verify a purely mathematical concept.  One can verify the preduction that a sync procedure (done from the midpoint say) indeed produces a valid sync by doing the verification by definition (which is not done at the midpoint), but that i8 a test that the physical behavior matches the mathematical model, not a verification of the mathematical definition.

As has been stated, we can derive a statement from Alice's abstraction about the physical configuration of her inertial frame i.e. her physical, "stationary system". This claim pertains to the reading on the clock at the midpoint. It is a logically necessary statement about the physical system, derived from her abstraction. As a statement about the configuration of a physical sysyem, it is subject to the rules of empiricism. Empirically speaking it is untestable. So, from a purely empiricial standpoint, it is an assumption.

The abstract mathematics doesn't necessarily imply that the clocks are synchronised.

No frame reference, so I don't disagree with this.

The Lorentz-Poincare interpretation also employs the Lorentz transformation between the relatively moving reference frames, but the clocks in those reference frames are not synchronised, under that interpretation.

By definition, yes.  Still not disagreeing.

The Lorentz transformation does not necessitate that simultaneity is relative because there are [at least] 2 difffering interpretations of the evidence which employ the LT. One interpretation concludes the relativity of simultaneity, the other doesn't, so RoS is not a necessity of the Lorentz Transformation.

It isn't stationary.  It is an arbitrary frame.  The fact that you found one mention of the word 'stationary' as a simple designation in Einstein's work is not an assertion that the frame is a preferred one.  I continue to harp on this because you're using the concept to give metaphysical meaning to something that isn't a metaphysical statement.

Apologie, I threw that in there in a state of exasperation in attempt to cover all bases. I am not imbuing the term "stationary" with any metaphysical qualities. My imprecise usage is causing some difficulty in some cases.

I didn't get the last bit: "will be the same for both events".  What events?  I assume the zeroing events of the clocks at B1 and B2, in which case I agree that the reading of d/c on clock at A would be simultaneous with those two zeroing events in the frame where all the clocks involved remain at their respective locations.

This is precisely what I meant. This is the statement about the configuration of the physical system that can be derived from Alice's abstraction. It is this that cannot be observed and which must be assumed. If either of the zeroing events is not simultaneous with this reading, then the two clocks are not synchronised. Alice has no way of verifying, empirically, that the zeroing events are simultaneous with this clock reading . Therefore, from an empirical standdpoint, she can only assume that this is the case.

Establishing it by definition is not assuming it.

Maybe not. However, it is the not being able to verify it empirically that makes it an assumption.

  She's quite capable of applying the definition and verifying it.  She has not done so in the procedure you describe above.  The definition doesn't involve a 3rd location.

She cannot verify it. As you have said yourself, the synchronisation of spatially separated clocks cannot be observed. If it cannot be observed, then it cannot be verified - at least not empirically.

[Halc]

I didn't say 'in her inertial frame'.

This is probably a big part of the issue. I am trying to clarify my thinking but I am using terms imprecisely/interchangably, which is probably leading to us talking past each other in some cases. I'm having a similar discussion on another forum with people who I'e debated against before, who are probably used to me doing this, so haven't been pulling me up on it, because they understand the point I am trying to make. So, I haven't learned to be more precise. So apologies if that is the case.

Let me correct my statement then.  One can empirically observe the simultaneity of clocks given an abstract coordinate system, using the empirical method described by Einstein's definition.  That definition is meaningless sans said coordinate system, hence my statement that one 'cannot observe synchronization of clocks' without specification of that choice of coordinate system.  Einstein's definition is entirely empirical, which means the state can indeed be observed, given a frame.
Alice in our examples has not been employing this method.

Apologies, can we walk thru this bcos I'm not fully clear on your reasoning here. I'll outline my understanding, sticking as closely to the Einsteinian synchronisation procedure as I can, and you can highlight where I'm going wrong - if that suits?

OK.  The synchronization procedure is not the same as the verification-by-definition procedure...  just so you know.  The former is how one goes about syncing the clocks in a frame, and the latter is one way to verify that they're indeed in sync in that frame.

You have the 2 clocks as you outline there. Let's call the clocks C1 and C2 for convenience. At time T0 on C1, you send the pulse to C2, which zeros C2. How do you measure the duration of the journey from C1 to C2?

The verification procedure (the 'by definition' one) doesn't zero anything.  When clock at C1 reads T1, it sends the pulse, which is received at C2 at T2 say.  The duration is T2-T1 as measured by those respective clocks.  That's the number we're after.  It might be negative, but the clocks are not in sync if it is negative.

or, do you mean:
that both clocks are started independently, not synchronously and at the random time T1a [on C1], a pulse is sent from one clock to the other clock [C2] which registers the time of T1b. Subtract the 2 values to get D1. This would give us a random value not necessarily the duration of the journey from C1 to C2 - because we don't know if the clocks were started simultaneously. Lets, for arguments sake, say that the value it gives us is 2 units of time.

This sounds better.  Yes, it doesn't matter what time the pulse is sent, so long as it is known.
All this is in Einstein's paper when he discusses the definition of synchronized clocks.  Did you not read it?  It seems you argue by parroting others (your peers) rather than actually reading the papers being criticized.

Then, at a random time T2b a pulse is sent from C2 to C1. The 2 values are subtracted to give D2. Let's imagine for a second though, that C2 was started 1 unit of time before C1. Subtracting the two values will give us 0 (assuming the same journey time).

Yes, except worded as 'clock at location C1, C2, not clocks C1 and C2'.  It's really important to distinguish between the two.  I see you got a duration of 2 one way and 0 the other way.  They're not in sync in that frame, by definition.

This is where the disconnect is, I think. We don't need to assume that she is making a metaphysical claim - even though such a claim has pretty drastic metaphysical implications pertaining the the physical structure of the universe, stemming from that claim.

How is this a disconnect?  We seem to agree that Alice is not making any metaphysical assumptions.  She's doing physics, not metaphysics.  The latter doesn't involve all the toy's she's playing with.

We need only talk about the physical system in which Alice finds herself, and the physical synchronisation procedure that she carries out. We're talking about empirical verification of Alice's claims. In this sense, her statement that the two clocks are in sync is not a purely abstract statement. It's a statement about the physical configuration of a real-world inertial system.

Again, she claims they're in sync in the one frame.  Different claim.  Agree with the rest.

But that abstraction is all that Alice is claiming.

And what we're doing is seeing how well Alice's abstraction maps onto the physical world. We're checking to see if her abstraction can be verified empirically.

Given Alice's abstraction we are free to derive/deduce other claims about the configuration of her physical system that follow as a necessity from her abstraction. Alice may not have expreessly stated these from the outset, as she may have been unaware of them, but as with any physicl theory/interpretation, we can see what it logically necessitates and go about testing that, empirically. In doing so, we can see that her abstraction includes a logically necessary statement about the simultaneity of clock synchronisation events and their coincidence with the reading on a clock located midway between them. This is simply a statement about the configuration of the physical system that we can deduce from Alice's abstraction and which gives us further insight into her interpretation.

All OK

As we have agreed, this part of Alice's abstraction cannot be verified empirically, that is, we cannot determine, by way of observation, that Alice's abstraction is an accurate representatation of the physical world.

We just agreed that there are all these verification tests that can be done and all the bit you just got finished typing.  Now you say that it cannot be done.  Pick a story please.  Alice is going to make all these additional observervations and every one of them will be a frame dependent observation, but that doesn't make them non-empirical tests.  She has a test for clocks being in sync, and given that plus a little trivial mathematical work, she can verify that the clock at the midpoint is indeed fast by d/c compared to either of the other two clocks.  Not compute it, but empirically verify it.

For Alice to maintain her belief in this abstraction she does so, not on the basis of empirical observation, she does so only by way of assumption.

And here you go with this assertion of assumptions again.  There is an empirical way to verify these things.  None of it is assumed.  Your comment doesn't follow at all.

In this sense, Alice's abstraction (co-ordinate reference frame) is the "map" and her physical, inertial frame is the territory.

The inertial frame is the abstraction.  The territory is all the toys.  You are making a metaphysical assumption in declaring an inertial frame to be a physical thing.  I'm not doing that, and neither is Alice.

As has been stated, we can derive a statement from Alice's abstraction about the physical configuration of her inertial frame i.e. her physical, "stationary system".

You stated that wrong.  The coordinate system is an abstraction, not a physical system.  I cannot go over and lean on the X axis.

This claim pertains to the reading on the clock at the midpoint. It is a logically necessary statement about the physical system, derived from her abstraction. As a statement about the configuration of a physical sysyem, it is subject to the rules of empiricism. Empirically speaking it is untestable. So, from a purely empiricial standpoint, it is an assumption.

It is quite testable, so not an assumption at all.  We had Alice doing just such a test. You're just making up false assertions without backing them.

The Lorentz transformation does not necessitate that simultaneity is relative because there are [at least] 2 difffering interpretations of the evidence which employ the LT.

Agree.  I said the sync verification procedure works with either interpretation.

One interpretation concludes the relativity of simultaneity, the other doesn't, so RoS is not a necessity of the Lorentz Transformation.

Agree.  Are you claiming I said otherwise?

I didn't get the last bit: "will be the same for both events".  What events?  I assume the zeroing events of the clocks at B1 and B2, in which case I agree that the reading of d/c on clock at A would be simultaneous with those two zeroing events in the frame where all the clocks involved remain at their respective locations.

This is precisely what I meant. This is the statement about the configuration of the physical system that can be derived from Alice's abstraction.

No, it is an abstract claim based on the abstract selection of coordinate system.  Claims of simultaneity are abstract claims.  They can be physically verified only given a choice of abstract coordinate systems.
If I had agreed that clocks C1 and C2 are in sync, that would be a metaphysical claim.  But I said clocks at locations C1 and C2 are in sync, and the location of said physical objects is entirely undefined without the abstract coordinate system. Doesn't matter where the origin is, but the abstract orientation of the axes is critical to defining an abstract concept like location.
I know, your interpretation has a preferred orientation and thus location is a property, not a relation to a coordinate system.  Alice is making no claims about such an interpretation since she's expended no effort in verifying that her clocks remain at their respective locations. Nailing them to the moving floor hardly suffices.

It is this that cannot be observed and which must be assumed. If either of the zeroing events is not simultaneous with this reading, then the two clocks are not synchronised. Alice has no way of verifying, empirically, that the zeroing events are simultaneous with this clock reading . Therefore, from an empirical standdpoint, she can only assume that this is the case.

Frame reference missing, so all this is meaningless.  If you mean to imply 'in her selected frame', then the statement is merely wrong, as per my comments above.

Maybe not. However, it is the not being able to verify it empirically that makes it an assumption.

I suppose it would be. Good thing we have an empirical verification that can be performed.

[the_roosh (OP)]

OK.  The synchronization procedure is not the same as the verification-by-definition procedure...  just so you know.  The former is how one goes about syncing the clocks in a frame, and the latter is one way to verify that they're indeed in sync in that frame.

OK, hopefully we can make some progress by focusing on this.

The verification procedure (the 'by definition' one) doesn't zero anything.  When clock at C1 reads T1, it sends the pulse, which is received at C2 at T2 say.  The duration is T2-T1 as measured by those respective clocks.  That's the number we're after.  It might be negative, but the clocks are not in sync if it is negative.

There is a critical issue with the statement "the duration is T2-T1 as measured by those respective clocks". The issue lies in the fact that we have not established a "common time" for both clocks.

If the clock at C2 started one unit of time before the clock at C1, such that when the clock at C1 reads T=0 the clock at C2 reads T=1 then the value T2-T1 will not accurately reflect the journey time for the pulse. If the pulse takes 1 unit of time to reach the clock at C2 then the reading on the clock at C2 will be T=2. Subtracting the two values will give a journey time of 2 units of time.

Now, if the pulse is reflected from the clock at C2 but takes 3 units of time in the opposite direction, it will arrive at the clock at C1 when that clock reads T=4. Subtracting the two values will give a journey time of 2 units of time. Concluding that the clocks are synced is clearly erroneous given the starting configuration of the system.

So, the method as you have outlined cannot be used to empirically verify the synchronisation of the clocks in any way, shape, form, frame or system.

[Halc]

There is a critical issue with the statement "the duration is T2-T1 as measured by those respective clocks". The issue lies in the fact that we have not established a "common time" for both clocks.

Maybe we shouldn't call it a duration then.  T1 is what the one clock at the first location reads when the pulse is sent from there.  T2 is what the seconds clock reads when the pulse is received from there.  Subtracting them gives a figure, and it seems to offend you to call it a duration, which seems fine since indeed, no common time has been established.  So we simply have a number that is the difference between the two readings.  The clocks literally can say anything, so this value can be any figure at all, positive or negative.  So let's just not call it a duration.

If the clock at C2 started one unit of time before the clock at C1 such that when the clock at C1 reads T=0 the clock at C2 reads T=1

You don't know this.  You can't make this assumption about something not yet measured.

then the value T2-T1 will not accurately reflect the journey time for the pulse. If the pulse takes 1 unit of time to reach the clock at C2 then the reading on the clock at C2 will be T=2. Subtracting the two values will give a journey time of 2 units of time.

Quite right.  Shouldn't call it a journey time then either.  Just a difference of 2 units between the pair of readings.

Now, if the pulse is reflected from the clock at C2

No reflection is part of the procedure.  The pulse can be sent at any time.  Yes, it can be done exactly at the moment the signal was received from location C1, but it doesn't have to be.  We just need to know what the clock there said when the pulse is sent.

from the clock at C2 but takes 3 units of time in the opposite direction. but takes 3 units of time in the opposite direction, it will arrive at the clock at C1 when that clock reads T=4. Subtracting the two values will give a journey time of 2 units of time. Concluding that the clocks are synced is clearly erroneous given the starting configuration of the system.

Both differences are empirically measured to be 2, so by Einstein's definition, the clocks are empirically in sync.  Only the empirical readings of the clocks were used to determine this.

I noticed that you needed to posit light speed in one direction (something you've asserted cannot be measured, and thus a metaphysical assumption) being thrice that of light going the other direction.  You're free to add this strange complication despite the fact that even most absolute interpretations (e.g. LET) will not posit it, but it doesn't change the empirical facts. In the frame in which they stay at their locations, the clocks have been measured to be in sync by definition.

I think you need to respond to post 46 which covers the earliest measurement of the speed of light, and which used a one-way method.  It would be a long time before a two-way method could be employed.  Your argument here seems to hinge on a metaphysical assumption of direction-dependent light speed.

[the_roosh (OP)]

Maybe we shouldn't call it a duration then.  T1 is what the one clock at the first location reads when the pulse is sent from there.  T2 is what the seconds clock reads when the pulse is received from there.  Subtracting them gives a figure, and it seems to offend you to call it a duration, which seems fine since indeed, no common time has been established.  So we simply have a number that is the difference between the two readings.  The clocks literally can say anything, so this value can be any figure at all, positive or negative.  So let's just not call it a duration.

I'm not offended at all by calling it duration. I was just pointing out the error in your reasoning. If you don't want to call it a duration that's fine, we can call it a figure or a reading or a value, whatever. The issues still remain.

You don't know this.  You can't make this assumption about something not yet measured.

It's called specifying the intial conditions of the experimental set-up.

There are an infinite number of ways in which the physical system can be configured. We are free to choose any configuration we like for the sake of argumentation. I'm simply just choosing one that best illustrates the error in your reasoning.

No reflection is part of the procedure.  The pulse can be sent at any time.  Yes, it can be done exactly at the moment the signal was received from location C1, but it doesn't have to be.  We just need to know what the clock there said when the pulse is sent.

Let a ray of light start at the “A time” tA from A towards B, let it at the “B time” tB be reflected at B in the direction of A (Einstein, 1905).

So,yes, it can be done at the moment the initial signal was received, which is why I constructed it that way as it is more intuitive.

Both differences are empirically measured to be 2, so by Einstein's definition, the clocks are empirically in sync.  Only the empirical readings of the clocks were used to determine this.

I have outlined a case where both differences are empirically measured to be 2, using only the empirical readings of the clocks to determine this. The initial conditions of the set-up were specified such that the clocks were not in sync but still both differences are empirically measured to be 2.

So, we have two competing explanations for both differences being empirically measured to be 2; one in which the clocks are synced one in which they aren't. As Alice cannot distinguish between the two scenarios on the basis of empirical observation, this set of empirical observations does not empirically verify the synchrony of the clocks.

But, here's the kicker: there are other empirical observations of the process, all of which show that the clocks aren't synchronised and that the light does take longer to travel in one direction than the other.

Therefore, any conclusion Alice draws about her clocks being synchronised is arrived at, not on the basis of empirical evidence but purely by assuming the conclusion to be true. This goes for any statement Alice makes about her clocks being synchronised, frame dependent or absolute - it matters not one jot, because there is simply no possible experiment she can conduct to empirically verify  the simultaneity of [spatially separated, clock synchronisation] events.

I noticed that you needed to posit light speed in one direction (something you've asserted cannot be measured, and thus a metaphysical assumption) being thrice that of light going the other direction.  You're free to add this strange complication, but it doesn't change the empirical facts.

You're correct, we are free to add this complication and it doesn't change the empirical facts. It is precisely that the empirical facts are not changed which allows us to draw the conclusion that Alice cannot distinguish between the two empirically and so, she can only rely on assumption to make the statement that her clocks are synced - in a frame dependent manner or an absolute manner.

In the frame in which they stay at their locations, the clocks are still in sync by definition.

The clocks stay in their locations in her inertial frame, bolted to the floor of her spaceship. As for the motion of her spaceship, Galileo taught us that that we cannot determine the nature of the inertial motion of her spaceship. So, whether or not one of the clocks advances towards the light pulse while the other moves away from it, Alice simply cannot determine this by way of experiment.

Any inertial co-ordinate system that implies that neither clock advances toward the light pulse and that neither clock moves away from it, is a co-ordinate system which carries with it the tacit assumption of the simultaneity of [clock synchronisation] events - an assumption that cannot be verified empirically and is in fact contradicted by the majority of empirical evidence.

I think you need to respond to post 46 which covers the earliest measurement of the speed of light, and which used a one-way method.  It would be a long time before a two-way method could be employed.  Your argument here seems to hinge on a metaphysical assumption of direction-dependent light speed.

I'll take a look at it again. Did you provide the provide the peer reviewed papers? From what I read you were trying to assert that attempts to measure the one-way speed of light came oh so, very nearly close to providing an exact measurement for the speed of light. This can be translated as, they demonstrated a variable speeed of light because it wasn't the defined value c.

Until you provide some sort of reference or link, I'm going to go with wikipedia and its references

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.

Experiments that attempted to directly probe the one-way speed of light independent of synchronization have been proposed, but none has succeeded in doing so.[3] Those experiments directly establish that synchronization with slow clock-transport is equivalent to Einstein synchronization, which is an important feature of special relativity. Though those experiments don't directly establish the isotropy of the one-way speed of light, because it was shown that slow clock-transport, the laws of motion, and the way inertial reference frames are defined, already involve the assumption of isotropic one-way speeds and thus are conventional as well.[4] In general, it was shown that these experiments are consistent with anisotropic one-way light speed as long as the two-way light speed is isotropic.[1][5]

Following one of the references led me to a book called Time, Tense, and Causation by Michael Tooley:

an assumption that is made by standard formulations of the Special Theory of Relativity, but which has no experimental support, and which may even be untestable in principle—the assumption,namely,that the measured one-way speed of light is a constant in all directions in all inertial frames.

The natural place to begin is with Einstein,and his original, 1905 formulation of the Special Theory. There, Einstein explicitly assumed that the one-way speed of light is a constant in all inertial frames. He did not,however, view that postulate as one for which there was experimental evidence. His position was rather that,while there is evidence for the assumption that the round-trip speed of light in a vacuum is a universal constant,the further postulate that the time taken for light to travel between two locations is the same in both directions is instead something which one establishes as true ‘by definition’.194 On Einstein's own approach,therefore,it is simply a matter of convention that the one-way speed of light in a vacuum is a constant.195. This idea that one can view it as true by definition that the oneway speed of light is a constant is a rather jarring one, and has given rise to a controversy that is still not yet fully resolved.

Thus,on the one hand,a number of philosophers, starting with Hans Reichenbach,have strongly defended the view that the non- conventional content of the Special Theory of Relativity precludes any experiment that could be used to determine whether the oneway speed of light is in fact a constant.196 But,on the other hand, a number of proposals have been advanced, and continue to be advanced,by physicists and others,concerning experiments that could be carried out to determine the one-way speed of light. The experiments proposed so far,however, all seem to be flawed,for, upon close scrutiny,all of the experiments appear to involve some principle or other that is true only if the one-way speed of light is a constant,and, if this is right, then none of the experiments proposed so far can possibly result in a value for the one-way speed of light which differs from that of the average round-trip speed.197

So, while Einstein explicitly assumes the one-way speed of light, by extension he tacitly assumes the simultaneity of events in the "stationary system" (frame dependent or otherwise) - in the case we have been discussing he tacitly assumes the simultaneity of clock synchronisation events. Therefore, the conclusion that simultaneity is relative is entirely circular.

Now, you can continue to try and frame the discussion however you like, but you there is no escaping the very simple fact that there is no experiment which can empirically determine that two spatially separated events are simultaneous (in any way, frame dependent or otherwise). Therefore, any conclusion that states that two [specific] events are simultaneous (in any way, frame dependent or otherwise) assumes that conclusion.

[Halc]

If the clock at C2 started one unit of time before the clock at C1 such that when the clock at C1 reads T=0 the clock at C2 reads T=1

You don't know this.  You can't make this assumption about something not yet measured.

It's called specifying the intial conditions of the experimental set-up.

You're making an assumption that gets contradicted by the empirical measurement taken.  The empirical test (the numbers you provided in your example) trumps the assumption, proving it incorrect.  You can't presume the peg to be square and measure it to be round and expect the presumption to still hold.

The pulse can be sent at any time.  Yes, it can be done exactly at the moment the signal was received from location C1, but it doesn't have to be.

Let a ray of light start at the “A time” tA from A towards B, let it at the “B time” tB be reflected at B in the direction of A (Einstein, 1905).

I'm just saying that it isn't a requirement.  It didn't say it wasn't allowed.

Both differences are empirically measured to be 2, so by Einstein's definition, the clocks are empirically in sync.  Only the empirical readings of the clocks were used to determine this.

I have outlined a case where both differences are empirically measured to be 2, using only the empirical readings of the clocks to determine this. The initial conditions of the set-up were specified such that the clocks were not in sync but still both differences are empirically measured to be 2.

Your assumption of the initial conditions (peg is square) was shown to be incorrect by an empirical measurement of a round peg.  The premise (of not-in-sync) was proven incorrect.  The empirical test passed.  The clocks are in sync in that frame by definition.

As Alice cannot distinguish between the two scenarios on the basis of empirical observation, this set of empirical observations does not empirically verify the synchrony of the clocks.

She can very much tell.  She sees that 2 = 2.  That's the only measured fact.  The premise that they're not in sync is demonstrably wrong.

But, here's the kicker: there are other empirical observations of the process, all of which show that the clocks aren't synchronised and that the light does take longer to travel in one direction than the other.

I don't recall Alice or anybody else measuring any such thing.   Wouldn't matter if they did, since the definition was satisfied.

You're correct, we are free to add this complication and it doesn't change the empirical facts. It is precisely that the empirical facts are not changed which allows us to draw the conclusion that Alice cannot distinguish between the two empirically and so, she can only rely on assumption to make the statement that her clocks are synced - in a frame dependent manner or an absolute manner.

No assumptions are made.  Light can be faster one way than the other if that interpretation makes you happy.  I know of no alternate interpretation that suggests this, but there's nothing invalid about it.  It doesn't change the fact that the clocks are synced in that frame by definition, and the premise about them not being synced is shown to be wrong.

I think your problem is that you're running with a different definition of being in sync than what Einstein describes.  If you want to show an inconsistency with Einstein's interpretation, you need to use his definitions.

Alice simply cannot determine this by way of experiment.

She doesn't have to.  She's chosen a coordinate system in which her stuff is stationary, a requirement of the test.  Her (purely abstract) conclusion then only applies to her choice of abstract coordinate systems.

I'll take a look at it again. Did you provide the provide the peer reviewed papers?

The guy is in the history books as the first to measure light speed. If his peers found his methods invalid, he would not hold that honor. It gained support by Newton and others and was confirmed 50 years later by different methods.

I also mentioned that you're probably looking for review from your peers, not his. Do some thinking for yourself for once and tell me what's wrong with his methods. Why can't a similar experiment be run today with our far more accurate clocks and such?

From what I read you were trying to assert that attempts to measure the one-way speed of light came oh so, very nearly close to providing an exact measurement for the speed of light.

Didn't say oh-so-close. He was off by about a quarter, which isn't bad considering they didn't have any idea how many zeros the figure would have before then.
As I said, the most accurate clock they had back then was a sundial.  But I assert that the test can be run today with under 1% error.

This can be translated as, they demonstrated a variable speeed of light because it wasn't the defined value c.

Not sure what you're talking about.  There was no defined 'c' back then.  They didn't know it to have a finite speed or a constant one.  The test can be (and was) repeated in different directions, and yields the same figure in any of them.

Until you provide some sort of reference or link, I'm going to go with wikipedia and its references

OK:
https://en.wikipedia.org/wiki/R%C3%B8mer%27s_determination_of_the_speed_of_light

Tell me what's wrong with it, and don't just quote some unrelated text that you interpret as meaning that what he did cannot have been done.

Following one of the references led me to a book called Time, Tense, and Causation by Michael Tooley:

an assumption that is made by standard formulations of the Special Theory of Relativity, but which has no experimental support, and which may even be untestable in principle—the assumption,namely,that the measured one-way speed of light is a constant in all directions in all inertial frames.

Newton assumed a direction-independent light speed, despite not assuming a frame independent one.  Yes, all interpretations of relativity (including absolute ones) assume a direction independent constant light speed.  You are allowed to posit an interpretation that does otherwise, but I don't see the point in such a needless complication.  If you do make such a premise, the definition of synced clocks needs to change accordingly.  You cannot discredit the relative interpretation by making contradictory premises like that.

Now, you can continue to try and frame the discussion however you like, but you there is no escaping the very simple fact that there is no experiment which can empirically determine that two spatially separated events are simultaneous (in any way, frame dependent or otherwise).

Lacking a premise of direction-independent light speed, I agree that the defined test for simultaneity doesn't work.

Therefore, any conclusion that states that two [specific] events are simultaneous (in any way, frame dependent or otherwise) assumes that conclusion.

Relativity makes a constant light speed premise, but the rest is derived from that premise, never assumed as you continue to assert.  The derivations are in the paper.  There is no conclusion made that light speed is constant, thus there is no circularity about it.

The fact that you continue on this line (plus your inability to address the Roemer thing) makes me suspect you incapable of thinking through any of this. You seem to just parrot other people's work without understanding any of it.

[the_roosh (OP)]

OK, I think I can see where the issue lies now.

  It doesn't change the fact that the clocks are synced in that frame by definition, and the premise about them not being synced is shown to be wrong.

I think your problem is that you're running with a different definition of being in sync than what Einstein describes.  If you want to show an inconsistency with Einstein's interpretation, you need to use his definitions.

You've mistakenly assumed that I am trying to demonstrate an inconsistency or contradiction in the Einsteinian interpretation and it is against this contention that you are arguing. You might be drawing inferences from other threads that I have started and incorrectly applying them in the context of this disucssion.

What I'm not doing
Let me state it once again: I am not trying to show an inconsistency with Einstein's interpretation - at least not in this line of discussion.

I understand that , by way of cognitive bias, those "defending" Einsteinian relativity tend to assume that I am attempting to show a contradiction in Einstein's interpretation. I know this bcos everyone I've discussed it with repeatedly states this misapprehension.

Indeed, for years this was the approach I had taken because I couldn't appreciate that Einstein's theory is internally self-consistent. Ideas still occur to me of ways in which a contradiction might be found but invariably they run into the fact that no contradiction/inconsistency can be found within Einstein's theory. It is internally self-consistent.

What I am doing
What I am saying, however, is that the conclusions of the Einsteinian interpretation are assumed i.e. the conclusions are arrived at through circular reasoning. Of course, this will not uncover an inconsistency in the Einsteinian interpretation, in fact, it assumes the internal consistency of the Einsteinian interpretation.

What is required
In order to demonstrate this circular logic we need only present an alternative interpretation of the evidence - as represented in the thought experiment. In order to do this we need only demonstrate that there is no way to distinguish between the two cases by way of empirical observation. On that basis we can see what the two - empirically equivalent - interpretations necessitate and draw conclusions from that.

I am also saying that it is possible to interpret the evidence in a manner that doesn't assume the conclusions. Untestable assumptions about an Ether, an absolute reference frame, and the simultaneity of events can be dropped without changing the mathematics of the theory or the predictions.

The Synchronisation [veriffication] Convention
Let's look at Einstein's synchronisation convention again. Remember, I'm not trying to demonstrate an inconsistency or a contradiction, I'm demonstrating that the simultaneity of clock synchronisation events i.e. the synchronisation of the clocks is assumed. It's not expressly assumed, it is tacitly assumed.

we establish by definition that the “time” required by light to travel from A to B equals the “time” it requires to travel from B to A.

This is the part that cannot be determined by way of empirical observation. It is an assumption, plain and simple. This is the expressed assumption.

We can extend this to the clock synchronisation experimental set-up with Alice. Yes, I know Einstein doesn't do that, but he doesn't mention anything about flying atomic clocks around the world either. We can extend his synchronisation convention to the thought experiment and make further deductions. When we do, we see that there is a  tacit - not expresssed - assumption that the clock synchronisation events are simultaneous in the "stationary system". It is assumed because - just like the “time” required by light to travel from A to B [equaling] the “time” it requires to travel from B to A - it arguablly cannot be determined empirically.

Let a ray of light start at the “A time” tA from A towards B, let it at the “B time” tB be reflected at B in the direction of A, and arrive again at A at the “A time” t0 A.
In accordance with definition the two clocks synchronize if tB - tA = t' A - tB

If tease this abstract convention apart, we can see that it simply boils down to:
"IF we sart with two clocks that are already synchronised and IF we assume that the time for a signal to go from A to B is the same as from B to A, then bouncing a light signal from A to B and back to A IF" tB - tA = t' A - tB then in accordance with definition the two clocks synchronize.

This is all fine, there is absolutely no problem with any of that. Incidentally, you might not recognise it bcos it isn't expressly stated, but the initial conditions that are implied include synchronised clocks.

We can start with different initial conditions however and say:
IF we start with two clocks that aren't syncronised, with one having started 1 unit of time before the other and IF we assume that the time from A to B is 1 unit of time while the time from B to A is 3 units of time and then we bounce a light pulse between them. In accordance with the definition, the two clocks are not synchronized if tB - tA = t' A - tB.

Here we have two different scenarios - one with clocks synchronised, one with clocks not synced - with the exact same empirical evidence. There is therefore, no way to distunguish between the two by way of empirical observation.

Now, it might be tempting to jump to the conclusion that choosing one over the other represents an equal assumption, but you'd be wrong, because the two scenarios - despite the empirical equivalence - are not equal.


Relativity of Simultaneity
As has been mentioned, there are two parts to the relativity of simultaneity:
1) Events which are simultaneous in one frame (the "stationary system")
2) are not simultaneous in relatively moving inertial frames

It is  number 1 above that is in contention because there is no experiment which can be carried out to reliably determine the simultaneity of spatially separated events. This is a direct consequence of the Galilean Principle of Relativity. When light signals arrive at an observer simultaneously from two equidistant locations (in the physical world), they cannot rule out the possibility that they were advancing towards one light signal, while retreating from the other. They simply cannot determine, by way of experiment, which is the case.

Establishing by definition that the observer [in their own frame] doesn't advance towards one and retreat from the other doesn't make it so, it simply assumes it to be the case.

You're making an assumption that gets contradicted by the empirical measurement taken.   The empirical test (the numbers you provided in your example) trumps the assumption, proving it incorrect.  You can't presume the peg to be square and measure it to be round and expect the presumption to still hold.

OK, maybe I'm being too presumptuous in assuming that you understand the concept of "the initial conditions of an experimental set-up". There are questions after this so we can try to diagnose where your lack of undderstanding lies.

In short:
We are free to choose any initial conditions for the experiment that we choose and then examine the empirical measurements that follow from those initial conditions. In our case, we choose initial conditions in which the clocks are not in sync. Why? Bcos we are perfectly entitled to and it allows us to demonstrates that the results of your empirical test do not empirically verify that the clocks are synced. How does it do this? It does this by demonstrating that the exact same empirical results are returned from an experimental set-up in which the clocks are not in sync.

======================
Do you understand the idea that - as a simple matter of fact - experiments necessarily start from "initial conditions"? Simply due to the fact that this is how the physical world works.

Do you understand that, theoretically, there are [as good as] an infinite set of initial conditions from which our experimental set-up can start? I say as good as just in case you have an issue with the idea of the infinite set. There are more possible initial conditions than we can possibly list - we could talk about irrelevancies such as the color of Alice's jumper or the stage of digestion that her breakfast is at.

Do you understand that we don't have to outline the outcomes for every single variation of the experiment; that we can select the one that best illustrates our point? We can do this because it represents a realistic example of the initial conditions that the experiment can start from.

In a nutshell: we can specify any [realistic] initial conditions we choose. In our case, I sepcified that one clock was started 1 unit of time before the other. Why? Bcos I am entitled to, and it is the easiest (or at least, it should be) to understand. We could specify other intial conditions with one clock starting 2/3/4/etc. units of time ahead of the other and vary the journey time for the pulse if we wish.

============================

The guy is in the history books as the first to measure light speed. If his peers found his methods invalid, he would not hold that honor. It gained support by Newton and others and was confirmed 50 years later by different methods.

I also mentioned that you're probably looking for review from your peers, not his. Do some thinking for yourself for once and tell me what's wrong with his methods.

Well, I wouldn't be so presumptuous to assume that I am a peer of those scientists who peer review papers for inclusion in journals, or those scientists who have peer reviewed papers that now represent accepted scientific fact. That is who you are talking about when you talk about "[my] peers" right? Bcos, that's what I mean when I talk about peer reviewed evidence.

He's in the history books because he demonstrated that the speed of light is finite, when the thinking at the time was that it was infinite/instantaneous. He isn't in the history books bcos his measurement in any way verifies that the one-way speed of light is constant, in all directions, in all inertial frames and is equal to the value represented by c.

His measurement was off by about 25%, as you mentioned. So, if you're holding this up as evidence for Einstein's interpretation of relativity, I'm arfraid you are achieving the opposite. If it were to be taken as a serious experimental test of Einstein's relativity it would invalidate it.

Is that the answer that "[my] peers" give? You seem to know better than me who these "peers" are.

[moved up] But I assert that the test can be run today with under 1% error. Why can't a similar experiment be run today with our far more accurate clocks and such?

You tell me! It would seem that for all of the experimental verification of Lorentz-Poincare Einsteinian relativity, accurately verifiying the one-way speed of light would strike me as the pièce de résistance. Could it be that do so, in a way that verifies Einstein's interpretation is not actually as easy as it might seem?

You're not the only one who asserts as much. Here is a snippet from a peer reviewed paper titled, A REVIEW OF ONE-WAY AND TWO-WAY EXPERIMENTS TO TEST THE ISOTROPY OF THE SPEED OF LIGHT. The authors share your optimism for the future measurement of the one-way speed of light. Unfortunately, they make it pretty clear that it hasn't yet been done.

If we compare the one-way experiments of [48] in Fig. 7 with the two-way experiments in Fig. 6, the results are about 4 to 6 orders of magnitude smaller in the one-way experiments than those of two-way experiments. Also the most recent one-way experiment performed by Krisher et al [79] in 1988 in NASA- Jet Propulsion Laboratory Deep Space Network (DSN) presents 2 orders of magnitude smaller values than that of NASA‟s previous experiment by Vessot et al [77, 78] in 1976. This is contradictory to our expectation based on STR [the Special Theory of Relativity] where we expect lower order of magnitude values with greater improvements.

The results of the one-way experiments are increasing in magnitude with time, whereas, the two-way experiments are decreasing in magnitude with greater precision and improvements with time. However, the results from the limits of the one-way experiments of [11] at the GRAAL facility are consistent with STR. But the regularity in the variations of the reported results of the GRAAL measurements reported in [11] in different timeperiods remains unclear and needs further experimental investigations.

=================
you'll like this part
=================

We have presented a comparison of experiments in Fig. 8 that shows the one-way speed of light measurement is approximately 2000 times more sensitive than that of round-trip test. Will [48] showed that experiments which test the isotropy in one-way or two-way (round-trip) have observables that depend on test functions but not on the particular
synchronization procedure. He noted that “the synchronization of clocks played no role in the interpretation of experiments provided that one is careful to express the results in terms of physically measurable quantities”. Hence the synchronization is largely irrelevant and one-way speed of light is measurable.

Results of the experimental tests spanning at least 24 hours periods in different seasons of the year should be recorded. Any hypothetical diurnal variations that might be observed should follow the figures presented in the
section 2.2 in Fig. 3 and Fig. 4.

But before we get too excited though:

Some authors such as Mansouri and Sexl (1977)[9][10] as well as Will (1992)[11] argued that this problem doesn't affect measurements of the isotropy of the one-way speed of light, for instance, due to direction dependent changes relative to a "preferred" (aether) frame Σ. They based their analysis on a specific interpretation of the RMS test theory in relation to experiments in which light follows a unidirectional path and to slow clock-transport experiments. Will agreed that it is impossible to measure the one-way speed between two clocks using a time-of-flight method without synchronization scheme, though he argued: "...a test of the isotropy of the speed between the same two clocks as the orientation of the propagation path varies relative to Σ should not depend on how they were synchronized...". He added that aether theories can only be made consistent with relativity by introducing ad-hoc hypotheses.[11] In more recent papers (2005, 2006) Will referred to those experiments as measuring the "isotropy of light speed using one-way propagation".[6][12]

However, others such as Zhang (1995, 1997)[1][13] and Anderson et al. (1998)[2] showed this interpretation to be incorrect. For instance, Anderson et al. pointed out that the conventionality of simultaneity must already be considered in the preferred frame, so all assumptions concerning the isotropy of the one-way speed of light and other velocities in this frame are conventional as well. Therefore, RMS remains a useful test theory to analyze tests of Lorentz invariance and the two-way speed of light, though not of the one-way speed of light. They concluded :"...one cannot hope even to test the isotropy of the speed of light without, in the course of the same experiment, deriving a one-way numerical value at least in principle, which then would contradict the conventionality of synchrony."[2] Using generalizations of Lorentz transformations with anisotropic one-way speeds, Zhang and Anderson pointed out that all events and experimental results compatible with the Lorentz transformation and the isotropic one-way speed of light must also be compatible with transformations preserving two-way light speed constancy and isotropy, while allowing anisotropic one-way speeds.

The alternative interpretation I have put forward above preserves the two-way light speed while incorporating anisotropic one-way speeds.

[Halc]

You've mistakenly assumed that I am trying to demonstrate an inconsistency or contradiction in the Einsteinian interpretation and it is against this contention that you are arguing. You might be drawing inferences from other threads that I have started and incorrectly applying them in the context of this disucssion.

You state, in this thread, that Alice makes one claim that is contradicted by some alternate claim by Bob. You seem to leverage this assessment of contradiction in order to push whatever alternate position (this atemporal universe as the title calls it) that you hold.
It would be a contradiction in the interpretation if they actually made contradictory claims as you state. I've been taking the position that all their claims are entirely consistent.

What I'm not doing
Let me state it once again: I am not trying to show an inconsistency with Einstein's interpretation - at least not in this line of discussion.

Let me quote the OP then:

While the observer in the "stationary" frame is performing this clock synchronisation, they observe a relatively moving observer perform the exact same synchronisation process. They are also located midway between 2 clocks. The light pulses are sent to each clock and reflected; crucially, the "stationary" observer sees the light pulses hit each clock not-simultaneously, get reflected, and arrive at the "moving" observer simultaneously. The "moving" observer concludes that their clocks are synchronised. The "stationary" has observed that the clocks are not synchronised.

Here, in the original thought experiment, we are provided with a clear case of why the assumption of synchronisation/simultaneity is unjustified.

My bold. You misrepresent the claims of the two observers (later to be named Alice and Bob) and also lay claim that assumptions were made (none were other than assumptions of the premises of SR, neither of which mention simultaneity).  It is that statement that prompted me to jump into this thread. The entire thread since then seems to have been about this, despite your claim here that it is not what you are doing. If you're not intending to show inconsistency with the interpretation, then don't claim said inconsistency in your OP like that.
Say it is fine, but here is some alternate interpretation. I notice that nobody is discussing that since you've taken the hostile route and declared the mainstream interpretation to be wrong.

What I am doing
What I am saying, however, is that the conclusions of the Einsteinian interpretation are assumed i.e. the conclusions are arrived at through circular reasoning.

You need to be far more explicit that this empty statement here.  The conclusion you seem to claim to be assume is the simultaneity of a pair of clocks in a given frame, but since a statement concerning simultaneity is not part of either of the premises of the interpretation, this doesn't hold water. Maybe you mean something else. Say it clearly instead of vacuously like that. There are exactly two assumptions made, and neither of them is listed as a conclusion.

So if your purpose here is to do that, you need to name the assumption that is the same as the conclusion.  Without that, there is no circularity, only A that leads to B without any additional assumptions. B doesn't lead back to A. Show me a circle, or your claims of this circularity are empty.

What is required
In order to demonstrate this circular logic we need only present an alternative interpretation of the evidence

There are valid alternative interpretations. In what possible way would that be evidence of the circularity of the first interpretation?

The mainstream alternative interpretation keeps constant light speed but replaces Galilean relativity with one where position become a property instead of a relation.  The sync definition outlined by Einstein still works perfectly in this interpretation.

You're suggested discarding the constant light speed premise as well. Then the sync definition doesn't work anymore. It is a strange interpretation, but not invalid if that's what you want to go with. Not sure if it is actually valid. Have to think about it.

In order to do this we need only demonstrate that there is no way to distinguish between the two cases by way of empirical observation.

Of course there is no way.  They wouldn't be interpretations if there was an empirical way to distinguish them. You don't need to demonstrate this since nobody asserts otherwise.
But none of this supports a claim that any interpretation assumes its conclusions.

we establish by definition that the “time” required by light to travel from A to B equals the “time” it requires to travel from B to A.

This is the part that cannot be determined by way of empirical observation. It is an assumption, plain and simple. This is the expressed assumption.

It directly follows from the 2nd premise of SR.  Even an absolute interpretation assumes that premise. Perhaps your interpretation does not.  Anyway, it isn't a 3rd premise. It follows from the 2nd. No additional assumptions have been made.

Let a ray of light start at the “A time” tA from A towards B, let it at the “B time” tB be reflected at B in the direction of A, and arrive again at A at the “A time” t0 A.
In accordance with definition the two clocks synchronize if tB - tA = t' A - tB

If tease this abstract convention apart, we can see that it simply boils down to:
"IF we sart with two clocks that are already synchronised and IF we assume that the time for a signal to go from A to B is the same as from B to A[/quote]Not an assumption. That is necessary given constant light speed.

then bouncing a light signal from A to B and back to A IF" tB - tA = t' A - tB then in accordance with definition the two clocks synchronize.

They are synchronized. The action doesn't synchronize the clocks if they were not before we did this.  The wording here makes it sound like the latter.

This is all fine, there is absolutely no problem with any of that. Incidentally, you might not recognise it bcos it isn't expressly stated, but the initial conditions that are implied include synchronised clocks.

Not so. It was a conditional. Iff they are synchronized, the condition  tB - tA = t' A - tB will be met, and if they are not, that condition will not be met. Alice need not assume the clocks are in sync in order to run the test.

We can start with different initial conditions however and say:
IF we start with two clocks that aren't syncronised, with one having started 1 unit of time before the other and IF we assume that the time from A to B is 1 unit of time while the time from B to A is 3 units of time

No you cannot. This violates the 2nd premise. Work out your own sync convention if you want to go with a different set of premises.  I stated above that the convention doesn't work if that premise is dropped. Even most absolute interpretations keep that premise, thus making this sync convention valid under them.

Here we have two different scenarios - one with clocks synchronised, one with clocks not synced - with the exact same empirical evidence. There is therefore, no way to distunguish between the two by way of empirical observation.

That why your alternate interpretation might be valid. It's why they're called interpretations.

Now, it might be tempting to jump to the conclusion that choosing one over the other represents an equal assumption

It represents an assumption of the two premises. No more. Your interpretation apparently doesn't assume either of them.

but you'd be wrong, because the two scenarios - despite the empirical equivalence - are not equal.

I never concluded that assuming those two premises is equal to assuming different premises. Where are you going with any of this?

Relativity of Simultaneity
As has been mentioned, there are two parts to the relativity of simultaneity:
1) Events which are simultaneous in one frame (the "stationary system")
2) are not simultaneous in relatively moving inertial frames

Not necessarily at least.  Pairs of events can definitely be simultaneous in more than one frame.  Anyway, I know what you mean, and yes, this is a conclusion drawn from the two premises.

It is  number 1 above that is in contention because there is no experiment which can be carried out to reliably determine the simultaneity of spatially separated events.

Number 1 is a sentence fragment identifying a pair of events, and your statement here is worded in a way that has no meaning under the interpretation. So it is like saying there is no experiment which can locate the invisible pink unicorn.

This is a direct consequence of the Galilean Principle of Relativity. When light signals arrive at an observer simultaneously from two equidistant locations (in the physical world), they cannot rule out the possibility that they were advancing towards one light signal, while retreating from the other.

Meaningless statement under the relative interpretation.  You are using language from a different interpretation.  That makes you the one making additional assumptions.

We are free to choose any initial conditions for the experiment that we choose

If they're in violation of the premises of a given interpretation, they are initial conditions for a different interpretation, and in no way invalidates the first interpretation.

I also mentioned that you're probably looking for review from your peers, not his. Do some thinking for yourself for once and tell me what's wrong with his methods.

Well, I wouldn't be so presumptuous to assume that I am a peer of those scientists who peer review papers for inclusion in journals

I said your peers, not Roemer's peers.  I presume you're not submitting papers to journals. Many of your arguments seem to come from your peers, and not from you.

He's in the history books because he demonstrated that the speed of light is finite, when the thinking at the time was that it was infinite/instantaneous. He isn't in the history books bcos his measurement in any way verifies that the one-way speed of light is constant, in all directions, in all inertial frames and is equal to the value represented by c.

His experiment can be reproduced today with modern measuring devices.  I am looking to you for a reason why his non-round-trip method is an invalid method to measure light speed.  Don't quote other sites which you interpret as asserting that it cannot be done.  Tell me why it can't be done.  Suppose light moved at thrice the speed in one direction as the other.  Wouldn't Roemer see triple the time if he did the experiment in one direction as the other? You evade this question because it is an apparent inconsistency in your 'initial condition' that not even the absolutist interpretation will take.  Resolve the inconsistency or conisder that interpretation to be falsified.

His measurement was off by about 25%, as you mentioned. So, if you're holding this up as evidence for Einstein's interpretation of relativity, I'm arfraid you are achieving the opposite. If it were to be taken as a serious experimental test of Einstein's relativity it would invalidate it.

Are you asserting that modern measurements would still be off by 25%?  That would indeed quickly falsify all modern interpretations, including LET, which still presumes direction independent light speed.  Here's your chance to be famous.  The experiment is pretty trivial.  Surely somebody would have noticed by now.

Is that the answer that "[my] peers" give? You seem to know better than me who these "peers" are.

No, I've not known anybody to suggest direction-dependent light speed before.  That's a new one.

You tell me! It would seem that for all of the experimental verification of Lorentz-Poincare Einsteinian relativity

I'm talking about experimental verification of your interpretation with direction dependent light speed.  Not even Lorentz-Poincare suggests that.
Roemer's results are entirely consistent with that interpretation.

I see you continue to quote wiki pages unrelated to what Roemer was doing.
He wasn't testing isotropy.  He was measuring light speed using a one-directional method.

[the_roosh (OP)]

You state, in this thread, that Alice makes one claim that is contradicted by some alternate claim by Bob. You seem to leverage this assessment of contradiction in order to push whatever alternate position (this atemporal universe as the title calls it) that you hold.
It would be a contradiction in the interpretation if they actually made contradictory claims as you state. I've been taking the position that all their claims are entirely consistent.

My bold. You misrepresent the claims of the two observers (later to be named Alice and Bob) and also lay claim that assumptions were made (none were other than assumptions of the premises of SR, neither of which mention simultaneity).  It is that statement that prompted me to jump into this thread. The entire thread since then seems to have been about this, despite your claim here that it is not what you are doing. If you're not intending to show inconsistency with the interpretation, then don't claim said inconsistency in your OP like that.
Say it is fine, but here is some alternate interpretation. I notice that nobody is discussing that since you've taken the hostile route and declared the mainstream interpretation to be wrong.

A couple of important points:
1) There is a difference between the explicit assumptions that Einstein starts with and the tacit assumptions required
     for the interpretation to be considered valid.

2) If something cannot be verifiied empirically but it forms part of your conclusion, then it is assumed to be true. That is
the nature of empiricism. Creationists employ this sort of reasoning to support their claims about God.

===================
We need to be careful about what we mean by the above - about Bob coontraddicting Alice's claims. The phrasing is too nebulous. Indeed, this is where the misunderstanding stems from. Essentially, you are restating the idea that the Einsteinian interpretation is self-consistent. As I have stated, I am not disputing that.

It is Alice's assumption that her clocks, in her own frame, are in sync - add all the qualifications in the world you like - which is rendered unjustified by the totaity of empirical observations. The evidence presented by Bob contradicts this assumption because the evidence presented by Bob shows that the clocks didn't sync.

Does Bob agree that Alice's clocks are in sync "in her own co-ordinate system"? Well, if he quotes the Book of Revelation Relativity and the Gospel according to Einstein: "Blessed are those who believe without seeing", then yes, he agrees with Alice's claims. But he doesn't do so on the basis of any empirical observations that he has made. Why is this? This is bcos the empirical observations that he has made show him that the clocks are not in sync.

The empirical evidence doesn't contradict the narrative that Alice constructs around this assumption because she employs circular reasoning. She cannot determine by way of empicism that her clocks are synced, in her frame, in Bob's frame, in any frame anywhere. The empirical evidence from Bob says her clocks didn't sync, so Alice constructs a narrative to justify her assumption.

It's like Alice stands at the shore of Loch Ness and claims that the Loch Ness Monster is in the lake, but due to unfortunate circumstances, she cannot actually verify this empirically. Then Bob drives past the lake and is able to survey the lake better from his vantage point. Bob's survey of the lake shows no sign of the Loch Ness Monster. This directly contradicts Alice's claim that the Loch Ness Monster is in the lake. Alice constructs a narrative which says that the Loch Ness Monster is only in the Lake if you are standing by the lake. But you can't actually observe the LNM. If you are in a car driving by the lake, then the LNM isn't in the lake, in your frame of reference. Therefore, the LNM being in the lake is frame dependent.

Alice devises a method of verification for her claim that the LNM is in the lake. Her verification method says:
IF the LNM is in the lake then, IF it breathes, we will see bubbles on the lake. Alice sees Bubbles on the lake and concludes that the LNM is there, even if she hasn't observed the LNM.

There is an alternative interpretation however, which says that the bubbles could come from other forms of aquatic life. Indeed, Bob's empirical survey of the lake shows bubbles being produced by other aquatic life.

The empirical verification that you point to only works IF we assume the clocks are already in sync and IF we assume the one-way speed of light is isotropic. At the current time of writing, there is no way that she can empirically verify either of these conditions*. If she cannot verify them, then their validity can only be assumed. This is further illustrated by presence of alternative interpretations which return the same empirical values from different starting conditions - conitions under which the clocks are not in sync and the one-way speed of light is not isotropic.

*as per the peer** reviewed literature I have referenced, the idea that it is even possible to measure the one-way speed of light in such a way that it supports Einstein's interpretation is highly debatable.

**reviewed by the peers of those who wrote the paper i.e. qualified scientists

You need to be far more explicit that this empty statement here.  The conclusion you seem to claim to be assume is the simultaneity of a pair of clocks in a given frame, but since a statement concerning simultaneity is not part of either of the premises of the interpretation, this doesn't hold water. Maybe you mean something else. Say it clearly instead of vacuously like that. There are exactly two assumptions made, and neither of them is listed as a conclusion.

So if your purpose here is to do that, you need to name the assumption that is the same as the conclusion.  Without that, there is no circularity, only A that leads to B without any additional assumptions. B doesn't lead back to A. Show me a circle, or your claims of this circularity are empty.

The "important points" 1 & 2 above address this. But in brief again:

Einstein's conclusion is that simultaneity is relative. That is, that events which are simultaneous in one frame are not simultaneous in relatively moving reference frames.

The simultaneity of spatially separated events (in any frame) cannot be determined empirically. If it cannot be determined by way of empirical observation, then any conclusion which incorporates it does so by way of assumption.

Einstein might not have started out with these explicit assumptions, but we can demonstrate that they are tacitly assumed - bcos they cannot be observed.

There are valid alternative interpretations. In what possible way would that be evidence of the circularity of the first interpretation?
...
Of course there is no way.  They wouldn't be interpretations if there was an empirical way to distinguish them. You don't need to demonstrate this since nobody asserts otherwise.
But none of this supports a claim that any interpretation assumes its conclusions.

The alternative interpretations are based on the exact same empirical obervations but they have Alice's clocks not being synced in her own frame. This demonstrates that the empirical evidence cannot be used to verify that the clocks are synced in the relevant frame.

It doesn't show that an interpretation which says they are synced is internally inconsistent, but it does show that an interpretation in which the clocks are synced [in the releant frame], assumes that the clocks are synced.

We can view the syncing of clocks in terms of the simultaneity of clock syncing events. So assuming the syncing of clocks [in the relevant frame] - by way of necessity - assumes the simultaneity of clock syncing events [in the relevant frame]. We can extrapolate this to a general statement about the assumption of the simultaneity of events being assumed.

Since the conclusion of Relativity of Simultaneity hinges on this, we can derive the conclusion that the conclusion of RoS is assumed.

The mainstream alternative interpretation keeps constant light speed but replaces Galilean relativity with one where position become a property instead of a relation.  The sync definition outlined by Einstein still works perfectly in this interpretation.

You're suggested discarding the constant light speed premise as well. Then the sync definition doesn't work anymore. It is a strange interpretation, but not invalid if that's what you want to go with. Not sure if it is actually valid. Have to think about it.

Not necessarily discarding it, rather replacing or reinterpreting it:
not that the round-trip speed of light is a constant relative to all inertial frames,but rather that the round-trip speed of light is a constant as measured within all inertial frames

It directly follows from the 2nd premise of SR.  Even an absolute interpretation assumes that premise. Perhaps your interpretation does not.  Anyway, it isn't a 3rd premise. It follows from the 2nd. No additional assumptions have been made.

Again, points 1 & 2 above, address this in the difference between explicit and tacit assumptions.

If something cannot be observed but it forms a critical part of a conclusion then it - and by extension the conclusion -  are assumed.

Not an assumption. That is necessary given constant light speed.

The isotropic one-way speed of light is an assumption bcos it has not been - and possibly cannot ever be - measured.

They are synchronized. The action doesn't synchronize the clocks if they were not before we did this.

Precisey my point about the implicit initial conditions.

The wording here makes it sound like the latter.

I noticed that too. You might want to take it up with the translator of the 1905 paper bcos I've quoted directly from that.

This is all fine, there is absolutely no problem with any of that. Incidentally, you might not recognise it bcos it isn't expressly stated, but the initial conditions that are implied include synchronised clocks.

Not so. It was a conditional. Iff they are synchronized, the condition  tB - tA = t' A - tB will be met, and if they are not, that condition will not be met. Alice need not assume the clocks are in sync in order to run the test.

Alice doesn't need to assume it bcos the initial conditions are tacitly (there's that word again) prescribed.

Implicit in the condition (tB - tA = t' A - tB = synced clocks) is the initial conditions in which the clocks are synced - you indirectly state this above.

Given that we can specify different intial conditions and derive a contradictory - yet empirically equivalent - condition (tB - tA = t' A - tB = non-synced clocks), this demonstrates that the "empirical verification procedure" cannot distinguish between synced clocks (with an isoptropic one-way speed of light) and unsynced clocks (with an isotropic round-trip speed of light). Therefore, any interpretation which involves a conclusion that relies on the former, necessarily assumess that conclusion.

No you cannot. This violates the 2nd premise. Work out your own sync convention if you want to go with a different set of premises.  I stated above that the convention doesn't work if that premise is dropped. Even most absolute interpretations keep that premise, thus making this sync convention valid under them.

Again, I'm not trying to demonstrate an inconsistency in the Einsteinian interpretation, I'm demonstrating a tacit assumption that is implicit within that interpretation.

The empirical test cannot distinguish between the two cases - because they are empirically equiavalent interpretations. From that, we can derive the tacit assumption about the syncing of clocks and the simultaneity of events (in the relevant frame).

That why your alternate interpretation might be valid. It's why they're called interpretations.

It is this which demonstrates - not an inconsistency within Einstein relativity - but the tacit assumption wiith regard to clock synchronisation/simultaneity of events.

Meaningless statement under the relative interpretation.  You are using language from a different interpretation.  That makes you the one making additional assumptions.

Again, not trying to show an inconsistency in the Einsteinian interpretation.

The fact that there are alternative, contradictory interpretations of the same [real-world] evidence, demonstrates that either one or both of them assumes their conclusions - bcos both can't be correct, despite being empirically equivalent.

If they're in violation of the premises of a given interpretation, they are initial conditions for a different interpretation, and in no way invalidates the first interpretation.

Indeed, they are initial conditions for a different interpretation. An interpretation which is empirically equivalent. That means that the evidence does not distinguish between the two. Given that they are contradictory interpretations, this demonstrates that - at least one of them - must be assuming its conclusions bcos both cannot be correct.

Again, I'm not trying to demonstrate a contradiction in the Einsteinian interpretation.

His experiment can be reproduced today with modern measuring devices.

What are the results of these modern day measurements and can you provide peer** reviewed papers that demonstrate that these measurements represent empirical verification of STR? I'm sure you realise that such a paper would be pretty big news, so if such exists you shouldn't have much trouble finding it. Obviously, "my peers" would like to keep this sort of thing suppressed which is probably why I haven't been able to find anything on it, but I'm sure you should have no trouble coming up with the goods.

I am looking to you for a reason why his non-round-trip method is an invalid method to measure light speed.  Don't quote other sites which you interpret as asserting that it cannot be done.  Tell me why it can't be done.

I don't need to know all of the reasons why it can't be done. The onus is on you to demonstrate how it has been done. I have referenced peer** reviewed literature that outlines reasons why all attempts thus far have failed. If you wish to adopt the position that those peer** reviewed papers are incorrect, go right ahead. You might have to base it on a litle more than your own "say-so" though.

But, just for your benefit, one of the reasons why it would appear that it cannot be measured accurately is because a "common time" would need to be defined at two spatially separated locations. As we have seen with Einstein's 1905 paper, this would seem to necessitate first assuming the isotropicc, one-way speed of light - circular reasoning anyone?

  Suppose light moved at thrice the speed in one direction as the other.  Wouldn't Roemer see triple the time if he did the experiment in one direction as the other?

Unlikely given that the sensitivity of such a one-wway measurement is "2000 times" more sensitive than that of a two-way measurement, and I don't think his equipment was up to it. I'm not sure modern equipment is up to it yet.

The other paper I quoted - which supports your position - also makes reference to other issues that need to be accounted for like measurements taken over a longer period of time, seasonal efects, etc. I can try to find out more reassons if you don't know the answer yourself.

You evade this question because it is an apparent inconsistency in your 'initial condition' that not even the absolutist interpretation will take.  Resolve the inconsistency or conisder that interpretation to be falsified.

Nope, I haven't evaded it. I just know that the 75%-accurate measurement of the speed of light made in the 1600s isn't an empirical verification of Einstein's interpretation of relativity. I chose to address it in a different manner by referencing peer** reiewed literature from this aeon. I even referenced literature that attempts to make your case, so as not to be biased.

And, while I might not fully appreciate the intricacies of the information, I do understand it somewhat. Indeed, I understand it enough to know that it supports my position. I also understand that it doesn't matter whether or not I understand it, what matters is whether or not it is correct.

If you wish to adopt the position that Rømer's measurement is an empirical verification of Einstein's theory, or if you want to adopt the position that the one-way speed of light has been measured in such a way as to conclusively distinguish between the competing interpretations of the evidence, please, feel free. We can then try to see what your peers make of that.

Are you asserting that modern measurements would still be off by 25%?   That would indeed quickly falsify all modern interpretations, including LET, which still presumes direction independent light speed.  Here's your chance to be famous.  The experiment is pretty trivial.  Surely somebody would have noticed by now.

Are you asserting that modern day measurements have been conducted such that they conclusively distinguish between the competing interpretations?

I'll leave the fame and glory to yourself when you produce experimental results that are free of the biases that all previous attempts are laiden with.

I see you continue to quote wiki pages unrelated to what Roemer was doing.
He wasn't testing isotropy.  He was measuring light speed using a one-directional method.

We are discussing Einsteinian relativity, so therefore we are discusssing the one-way, isotropic speed of light - because that is what is pertinent to Einstein's relativity. If you think the information I posted is not relevant to the case of Rømer, then ipso facto, Rømer isn't relevant to this discussion - because the stuff I referenced is relevant Einsteinian relativity.



**reviewed by the peers of those who wrote the paper i.e. qualified scientists