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11-06-2019, 20:13   #16
Morbert
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Originally Posted by roosh View Post
Einstein's clock synchronization procedure unequivocally states that clocks are assumed to be synchronized in "the stationary system"
You're still putting the cart before the horse here. The clocks are only considered to be synchronised under the standards of observations defined by the appropriate frame of reference.

It's not a case of "the clocks are synchronised therefore a reference frame is established". It's a case of, "the reference frame in which the system is described as stationary will describe the clocks as synchronised by the appropriate procedure"

It is one thing to suggest some Lorentz-Poincaire-type dynamics as an explanation for relativistic phenomena. It is another to suggest that the orthodox geometric account of relativistic phenomena is inconsistent.

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[A "common time"] cannot be defined at all unless 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.

Here we have the assumption of the Simultaneity of clock synchronization events.
This is stipulated by the reference frame. It is a definition established by our choice of reference frame. It is not an assumed metaphysical fact upon which we establish the reference frame.

Last edited by Morbert; 11-06-2019 at 20:16.
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11-06-2019, 20:30   #17
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So, the observer in "the stationary system" assumes that their clocks are synchronized while an infinite number of relatively moving observers have empirical evidence to the contrary. Relativity of Simultaneity rests entirely on this one observers assumption of the Simultaneity of events in their frame - despite the infinite amount of empirical evidence to the contrary.
This occurs in spatial geometry. I could say that one object is directly to the left of another and be correct given my facing. Somebody else facing a different direction would not agree. Notions of left of, behind, in front of are relative to the coordinate system of the observer.

I could say that I should regard nothing as "to the left" of anything else since an infinite number of observes would disagree. However that's exactly what I should expect since "left" is a coordinate dependent notion.

Similar in Special Relativity you should expect that different observers would disagree with your notion of "at the same time" because it's a coordinate relative statement.

Others producing evidence to the contrary is exactly what should happen if simultaneity is relative.

However the main point is that the relations between observers form a group with Minkowski space as its homogeneous space. Thus everything is in accord with thinking observers live on a Minkowski spacetime: different coordinates disagree and the relations between coordinates form the Poincaré group.
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12-06-2019, 05:08   #18
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@Morbert & @Fourier (and anyone else that may chooose to reply), I do want to make it known again, how apprecitive I am of you taking the time to reply. I am acutely aware that I fall distinctly into the "crackpot" category and how infuriatingly annoying it can be to discuss such issues with such "crackpots". I am having similar discussions elsewhere and the posters here on boards, have been the most patient and most helpful in pointing out the errors in my reasoning.

I sometimes find myself replying out of frustration that the point I am trying to make hasn't been "understood" - in previous discussions it has usually been the case that it was I that didn't understand some facet of the Einsteinian interpretation which rendered my "paradoxes" null and void. Sometimes the frustration with which I reply is as a result of the cumulative frustration from the other discussions combined. I just wanted to stress that it is never personal and again that I am deeply appreciative of the time you guys have given me over the years. I don't mean this to sound too sentimental, but you guys do a great service in offering to raise the scientific literacy of anyone ye engange with. Indeed, my [finally] being able to accept the internal consistency of the Einsteinian interpretation - it only took what, 10yrs? - is evidence to that effect.

The end result of this current discussion might be that you guys successfully show me the error in my reasoning again and I continue my [glacial] advancement towards a better understanding of the physical theories of science - I believe Paddy Power are already paying out. There is the smaller, highly improbable chance that I will demonstrate my argument in such a way that I change your perspectives. Such an eventuality would surely have to be taken as evidential support for the many worlds interpretation of QM in the sense that there really is a universe out there for every possible eventuality.

While it might seem like I seem to lack the self-awareness that might lead me to conclude that it is the first of the 2 scenarios above that is the most likely, my reasoning as to why "this time is different" is because I am not arguing against the self-consistency of relativity, I am advocating for a different interpretation. One which can be differentiated from the Einsteinian interpretation on the basis of empirical observation.
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12-06-2019, 05:54   #19
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You're still putting the cart before the horse here. The clocks are only considered to be synchronised under the standards of observations defined by the appropriate frame of reference.

It's not a case of "the clocks are synchronised therefore a reference frame is established". It's a case of, "the reference frame in which the system is described as stationary will describe the clocks as synchronised by the appropriate procedure"
I'm not sure if you remember in our previous discussions, but that is precisely how outlined the establishing of a reference frame; it involved populating the universe with synchronised clocks at rest relative to the observer - I think the point I was arguing was how an observer could be at rest relative to a set of imaginary, mathematical co-ordinates. It's not necessarily a point we need to get back into

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This is stipulated by the reference frame. It is a definition established by our choice of reference frame. It is not an assumed metaphysical fact upon which we establish the reference frame.
This would seem to suggest that the set of [imaginary] mathematical co-ordinates [chosen to describe physical events] bestows metaphysical properties upon the universe in the form of the Relativity of Simultaneity; together with the physical structure necessitated to accommodate it.

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It is one thing to suggest some Lorentz-Poincaire-type dynamics as an explanation for relativistic phenomena. It is another to suggest that the orthodox geometric account of relativistic phenomena is inconsistent.
Some key points here:

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

2) We don't need to rely on dynamics in a Lorentz-Poincare style interpretation; bcos an LP style formulation can be derived in an entirely kinematical manner, following the Einsteinian approach - as I will try to outline below.

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

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

3) The clock synchronisation thought experiment can be taken to represent a possible real-world, experimental set-up that can be used to test the assumption of Einstein's clock synchronisation convention - if the assumption is determined to be invalidated, then we are left with an alternative interpretation that has been derived kinematically.



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

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

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

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

The alternative is one where we equally have to accept that observers are both right and wrong, but it is the infintiely more palatable case where obervers are mistaken in their assumptions and it is the observational evidence which is correct.

Upon dropping the assumption of simultaneity of clock synchronisation events we are left with a purely kinematical derivation of the theory which extends the Galilean Principle of Relativity to simultaneity/synchronisation because, when you think about it, there is no way to determine that two events are simultaneous. We can determine that light signals from two events arrive at a detector simultaneously, but this cannot be used to determine the simultaneity of those events.
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12-06-2019, 06:21   #20
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This occurs in spatial geometry. I could say that one object is directly to the left of another and be correct given my facing. Somebody else facing a different direction would not agree. Notions of left of, behind, in front of are relative to the coordinate system of the observer.

I could say that I should regard nothing as "to the left" of anything else since an infinite number of observes would disagree. However that's exactly what I should expect since "left" is a coordinate dependent notion.

Similar in Special Relativity you should expect that different observers would disagree with your notion of "at the same time" because it's a coordinate relative statement.
The problem with this analogy is that, despite the co-geometrisation of space and time, both still maintain distinct properties, so statements about the properties of one doe not necessarily extend to the other. A key difference is that we can move to and fro in space but we can't move around in time. We can simultaneously hold obejects on the left and right in our conscious observtion, while we cannot do the same with "past" and "future" or "before" and "after", which are key aspects related to the notion of simultaneity.



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Others producing evidence to the contrary is exactly what should happen if simultaneity is relative.

However the main point is that the relations between observers form a group with Minkowski space as its homogeneous space. Thus everything is in accord with thinking observers live on a Minkowski spacetime: different coordinates disagree and the relations between coordinates form the Poincaré group.
Can I refer you to my most recent reply to Morbert immediately above this (just in case you haven't read it). I wil give an abridged version of the point here.

It is indeed in accord with the Minkowski spacetime interpretation, that is just one such interpretation. One I believe is not justified, on the basis of [implied] obervational evidence. Incidentally, the 4D Minkowski metric applies equally to the Lorentz-Poincare interpretation, however it is treated as a purely mathematical construct i.e. as a mathematical tool. I've read that the same is true in QFT.

The alternative Lorentz-Poincare style interpretation, is one without the relativity of simultaneity, and the clock synchronisation thought experiment represents a potential real-world experiment to test Einstein's synchronisation convention. It ends up with a potential mountain of emprical evidence that clocks in a given "stationary system" are not synchronised versus the assumption of the observer in "the stationary system" that the clocks are synchronised.

The solution to this, in Einsteinian interpretation, is to allow for disgreement between observers and it results in the conclusion that simultaneity is relative. When one observer assumes that events in their frame are simultaneous while all other observers provide evidene that they are not simultaneous - and the assumption is allowed to stand in the face of the contrdictory evidence - the necessary conclusion is RoS. Make no mistake though, it self-consistent only on account of it's circularity.

An alternative interpretation sees the lone observer drop their assumption in the face of conflicting evidence.
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12-06-2019, 08:09   #21
Fourier
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The problem with this analogy is that, despite the co-geometrisation of space and time, both still maintain distinct properties, so statements about the properties of one doe not necessarily extend to the other. A key difference is that we can move to and fro in space but we can't move around in time. We can simultaneously hold obejects on the left and right in our conscious observtion, while we cannot do the same with "past" and "future" or "before" and "after", which are key aspects related to the notion of simultaneity.
That's due to the geometry being different. Since the geometry is of a different type (Lorentzian vs Euclidean) of course there will be features present in one and not present in the other.

However this doesn't affect features common to both and indeed all geometries, i.e. the relative nature of coordinate statements.

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It is indeed in accord with the Minkowski spacetime interpretation, that is just one such interpretation. One I believe is not justified, on the basis of [implied] obervational evidence.
That observational evidence is exactly in accord with the Minkowski spacetime view though, this is what you are missing. If "time" is just part of a coordinate definition on Minkowski spacetime you should expect other observers to disagree with you. There is no observational evidence that contradicts this view.

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I've read that the same is true in QFT.
If you mean the metric is treated as a tool in QFT this is false, it's treated the same way as in conventional treatments of Special Relativity.

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Make no mistake though, it self-consistent only on account of it's circularity.
Minkowski spacetime is as self-consistent in a non-circular manner as Euclidean geometry, since both can be constructed from the ZFC axioms of mathematics. I don't want to drag this off topic, but you won't get anywhere with this statement as it can be verified by a computer.
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12-06-2019, 09:35   #22
roosh
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That's due to the geometry being different. Since the geometry is of a different type (Lorentzian vs Euclidean) of course there will be features present in one and not present in the other.

However this doesn't affect features common to both and indeed all geometries, i.e. the relative nature of coordinate statements.
The fact that we can't move to and fro in time or that we can't simultaneosuly view before and after are not matters of geometry, they are simple facts of existence which apply to our empirical obsservations.

The idea that the relative notions of "on the left" or "on the right" changes upon rotation doesn't require an assumption. The idea that events are simultaneous in your frame does. The simultaneity of events in your reference frame cannot determined by your choosing of a co-ordinate reference frame. Your co-ordinate reference frame might describe them as being simultaneous, but this implies that there is an underlying assumption of simultaneity.


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That observational evidence is exactly in accord with the Minkowski spacetime view though, this is what you are missing. If "time" is just part of a coordinate definition on Minkowski spacetime you should expect other observers to disagree with you. There is no observational evidence that contradicts this view.
The contention isn't that it is not in accord with the Minkowski spacetime view. As has been mentioned, the mathematics of Minkowski spacetime apply equally to a Lorentz-Poincare interpretation. The difference being the ontological status attributed to both - in the LP interpretation the mathematics of Minkowski are simply that, mathematical. They are a useful mathematical tool.

The LP interpretation does not incorporate RoS. This demonstrates an alternative interpretation. So, yes, the Einsteinian/Minkowskian (EM) interpretation is one possible interpretation which is internally consistent. The kinematical LP interpretation is another such interpretation.

The clock synchronisation thought experiement can be viewed as a potential real-world experiment, that could possibly tell us something about both interpretations. As has been outlined, the EM interpretation is predicated on a foundational assumption which requires that assumption to be maintained in the face of overwhelming empirical evidence to the contrary.


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If you mean the metric is treated as a tool in QFT this is false, it's treated the same way as in conventional treatments of Special Relativity.
The Minkowski metric of quantum field theory is generally regarded as a mathematical construct and not a real physical object. (Bryan and Medved, 2018 - the Problem with the Problem of Time)


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Minkowski spacetime is as self-consistent in a non-circular manner as Euclidean geometry, since both can be constructed from the ZFC axioms of mathematics. I don't want to drag this off topic, but you won't get anywhere with this statement as it can be verified by a computer.
The synchronisation thought experiment can be taken to represent a real-world experimental set-up which allows us to deduce certain facts about competing interpretations.

The thought experiment demonstrates that the assumption of simultaneity of events in "the stationary frame" is juxtaposed with observational evidence to the contrary.

There are [at least] 2 possible interpretations that can applied.

One of them allows the assumption to stand, despite the evidence, and concludes that "events which are simultaneous in one frame are not simultaneous in relatively moving frames" i.e. concludes that simultaneity is relative - as can clearly be seen, this is simply assuming the conclusion. Minkowski spacetime is the physical structure which is required for RoS to have any real physical meaning - something that is not without its own issues. The physicality of Minkowski spactime is an ongoing matter of debate, however, for RoS to be different from/incopatible with the notion of absolute simultaneity, Minkowski spacetime, in the form of "the Block Universe' (or any variation thereof that relies on RoS) must represent the underllying physical structure of the universe. The argument in the paper is that such a universal structure cannot allow for relative motion or the observation thereof.


The other interpretation simply inolves giving higher status to observational evidence than assumptions. It simply requires the assumption of simultaneity [in the "stationary system"] to be dropped in the face of empiricl evidence to the contrary. Dropping this assumption leaves us with a kinematical description that doesn't incorporate RoS and is therefore free of any of the issues associated with "the Block Universe". It also serves to align the conceptualisation of time in relativity with that of QM. Adjusting our idea of "time" and viewing it as a non-fundamental, non-emergent system of measuremen, further allows us to drop any background dependence, that may or may not be an issue.
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12-06-2019, 10:28   #23
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The Minkowski metric of quantum field theory is generally regarded as a mathematical construct and not a real physical object. (Bryan and Medved, 2018 - the Problem with the Problem of Time)
It's not see:
Peskin and Schroeder, Introduction to Quantum Field Theory
Weinberg, The Quantum Theory of fields
Zee, Quantum Field Theory in a Nutshell
Itzykson and Zuber, Quantum Field Theory

These are actual textbooks on Quantum Field Theory used by generations of particle physicists and thus reflect standard usage.

On a personal level, having actually worked in Quantum Field Theory general usage is not as you claim.

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The fact that we can't move to and fro in time or that we can't simultaneosuly view before and after are not matters of geometry, they are simple facts of existence which apply to our empirical obsservations.
In the Minkowskian view they are a consequence of geometry and hence in that view are analogous to "left" and "right". Even how left and right function is a "simple fact of existence", but it is explained in terms of Euclidean geometry.
The whole point of Minkowski space is how it explains these facts and their relations.

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maintained in the face of overwhelming empirical evidence to the contrary
Once again though this isn't evidence to the contrary this is what I have been saying over and over again. It's exactly what you would expect from living in Minkowski space. Empirical evidence to the contrary would be actual observations differing from that predicted by the Minkowski picture, this is not the case here.
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12-06-2019, 10:31   #24
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The physicality of Minkowski spactime is an ongoing matter of debate, however, for RoS to be different from/incopatible with the notion of absolute simultaneity, Minkowski spacetime, in the form of "the Block Universe' (or any variation thereof that relies on RoS) must represent the underllying physical structure of the universe
Minkowski spacetime doesn't require a Block Universe. Some people at times use it to argue for a Blockworld, but these are separate things.
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12-06-2019, 11:28   #25
roosh
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It's not see:
Peskin and Schroeder, Introduction to Quantum Field Theory
Weinberg, The Quantum Theory of fields
Zee, Quantum Field Theory in a Nutshell
Itzykson and Zuber, Quantum Field Theory

These are actual textbooks on Quantum Field Theory used by generations of particle physicists and thus reflect standard usage.

On a personal level, having actually worked in Quantum Field Theory general usage is not as you claim.
Ok, I'll take your point. I'll check out those references, thank you!

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In the Minkowskian view they are a consequence of geometry and hence in that view are analogous to "left" and "right". Even how left and right function is a "simple fact of existence", but it is explained in terms of Euclidean geometry.
The whole point of Minkowski space is how it explains these facts and their relations.


Once again though this isn't evidence to the contrary this is what I have been saying over and over again. It's exactly what you would expect from living in Minkowski space. Empirical evidence to the contrary would be actual observations differing from that predicted by the Minkowski picture, this is not the case here.
I think you're slightly missing the point. I'm not sayinng that it is evidence contrary to the EM interpretation.

As mentioned, the thought epxeriment can be taken to represent a [potential] real-world experimental set-up and as such, it allows us to make a number of deductions about our competing interpretations; that is, we can learn something about the interpretations by considering it.

The EM interpretation is fully consistent with the observational evidence. The contention is that it applies an assumption, along with that observational evidence, which the observational evidence itself renders unjustified.


For a moment, try to shelve any thoughts about Minkowski spacetime - bear in mind, I am saying that Minkowski spacetime is consistent with the obervational evidence - and lets consider the thought experiment solely on its own merits. We can view it as an empirical test of Einstein's clock synchronisation convention.

Without going through the whole thing again, Alice performs the synchronisation procedure. The light signals return simultaneously to her and she assumes her clocks are synchronised that is, she assumes the simultaneity of [clock synchronisation events] in her "stationary system".

All other, relatively moving, observers provide empirical evidence that the [clock synchroonisation] events were not simultaneous and that her clocks are not synchronised. This empirical evidence doe not support her attempt to establish a "common time" for her clocks ; her attempt to "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" is not supported by the empirical observations.

So, Alice is at a crossroads, two possible interpretations, leading in opposite directions.

She can maintain her insistence that the clock synchronisation events, in her "stationary system", were simultaneously. She can maintain that all other observers are wrong/mistaken and that it is her assumption that is correct. If she chooses this route, she will arrive at the conclusion that simultaneity is relative. This is a conclusion necessitated by maintaining that both her assumption and the observational evidence are correct - despite the observational evidence contradicting her assumption. Incidentally, she must also accept that she is mistaken and that the others are correct.

To reiterate, the Relativity of Simultaneity says that events which are simultaneous in one reference frame [the frame of the "stationary system"] are not simultaneous in a relatively moving frame. The observational evidence says that the [clock synchronisation] events in Alice's frame were not simultaneous, while Alice assumes that they were. Hence, the conclusion is assumed.

Down this route lies Minkowski spacetime.


Back at the crossroads, the other road - the other interpretation - simply involves Alice dropping her assumption.

Last edited by roosh; 12-06-2019 at 11:40.
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12-06-2019, 11:34   #26
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Minkowski spacetime doesn't require a Block Universe. Some people at times use it to argue for a Blockworld, but these are separate things.
"The Block Universe" is simply the philosophical interpretation of Minkowski spacetime. While Minkowski spacetime may siimply be a mathematical representation of spacetime, there are deductions that can be made about it that are then illustrated through the block world conceptualisation.

The same deductions could be made without the imgagination of the 4D block
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12-06-2019, 12:07   #27
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She can maintain her insistence that the clock synchronisation events, in her "stationary system", were simultaneously. She can maintain that all other observers are wrong/mistaken and that it is her assumption that is correct. If she chooses this route, she will arrive at the conclusion that simultaneity is relative
Alice doesn't assume she is correct though in the standard Minkowskian view though. She assumes she has a working definition of a time coordinate, but not that it is absolutely correct and everybody else is wrong. Doing that would be to assume absolute time. She simply assumes it is a functioning way of defining time for her own purposes and she will be able to demonstrate that it and every other method of defining time will be disagreed with by others. In the Minkowskian view this is fine since all such definitions are ultimately just coordinates so you wouldn't expect anything else.

There is no assumption that she is right and others are wrong.
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12-06-2019, 12:08   #28
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"The Block Universe" is simply the philosophical interpretation of Minkowski spacetime
My point was that there are alternate readings where Minkowski geometry is real, but there isn't a Blockworld. They're not synonymous.
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12-06-2019, 12:48   #29
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Alice doesn't assume she is correct though in the standard Minkowskian view though. She assumes she has a working definition of a time coordinate, but not that it is absolutely correct and everybody else is wrong. Doing that would be to assume absolute time. She simply assumes it is a functioning way of defining time for her own purposes and she will be able to demonstrate that it and every other method of defining time will be disagreed with by others. In the Minkowskian view this is fine since all such definitions are ultimately just coordinates so you wouldn't expect anything else.

There is no assumption that she is right and others are wrong.
Again, the contention isn't that the above isn't fine with the Minkowski view. As you highlight above, the Minkowski view is predicated on certain assumptions about the working definition of the time co-ordinate. The thought experiment allows us to investigate alternative interpretations and some of the consequences of those interpretaions.

Also, I didn't necessarily state that she assumes that it is absolutely correct and everybody else is wrong, I mentioned at the end that she must also accept that she is wrong and everyone else is right. In anyones language, this would represent a contradiction, but this is taken to be a feature, not a bug, of the Einsteinian interpretation.

Just for the sake of clarifying a point, let's label the implements that Alice uses in her synchronisation set-up. Let's label the emitter as A, the clock on one side as B1 and the clock on the other as B2.

In the real-world experimental set-up, as represented in the thought experiment, she assumes that the time the light signal takes from A to B1 equals the time from B1 to A, as well as assuming that the time the light signal takes from A to B2 equals the time from B2 to A, together with the assumption that the time for A to B1 equals A to B2, and the assumption that B1 to A equals B2 to A.

These assumptions are encoded in her choice of co-ordinate system and working definition of a time coordinate.

The observational results from the experiment do not support the above assumptions.

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She simply assumes it is a functioning way of defining time for her own purposes and she will be able to demonstrate that it and every other method of defining time will be disagreed with by others.
This is essentially agreeing with the point being made. Yes, she assumes - assumes being the operative word - that it is a functioning way of defining time for her own purposes and she also knows that others will disagree with it. The whole point being made is that Alice assumes it is functioning way of defining time, while others base their disagreements on emprical observations.

Essentially, this disagreement IS the Relativity of Simultaneity. Alice assumes her definition of time is valid, while all other observers disagree on the basis of empirical observation. It is Alice's continuing insistence that her assumption is valid that gives rise to the conclusion of RoS - without her assumption all that is left is the observational evidence that the events were not simultaneous.



Can you, at the very least, see the alternative interpretation that doesn't rely on the Relativity of Simultaneity, and that equally explains all the evidence? One in which the matematics of Poincare/Minkowski are taken to be just a mathematical construct?
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12-06-2019, 13:02   #30
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My point was that there are alternate readings where Minkowski geometry is real, but there isn't a Blockworld. They're not synonymous.
I won't necessarily argue that point. I know that Carlo Rovelli - in the Order of Time - argues for a different interpretation. He talks about some kind of a filial structure, like a family tree. He doesn't really put it together very well. Even this sort of structure, however, requires mini-blocks for each structure. There are others too, llike Julian Barbours etc. Am I correct in saying that records theories and theories of shape dynamics (I remember @Morbert mentioning that before), represent other such examples?

I would say, however, that the very idea of a temporal dimension, or being "extended in time" necessitates a block structure. To be extended in time requires either/both of a systems past and/or future configurations to co-exist along with it's present configurtion. If only the present configurtion makes up part of the universal structure, then the system cannot be said to be "extended in time" in any physically, meaningful way. Also, it would mean that the temporal dimension is pointlike.
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