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Question on Lorentz transforms and relativity of simultaneity
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No, just that the other thought occurred to me, so I decided to pursue it instead.The above is completely unrelated to anything I said.
So does this mean you accept that no contradiction is evident in your previous thought experiment?
How is that? If the speed of sound is constant relative to the medium through which it travels, then shouldn't the sound waves arrive at the midpoint simultaneously in one reference frame but not in the other?In your new thought experiment, the light switches on according to all observers. Just as, in the previous thought experiment, with photons instead of sound, the light switched off according to all observers.0 -
The assumption about the light device was one which dlouth (I think it was) introduced previously; it's the same light device. Morbert has stated previously that we are free to introduce such hypothetical devices.
I don't think it matters though because we can presumably exploit the disagreement over the simultaneity of events which occur at the same location in space and time, according to one reference frame, in other ways.
The assumption you made is that the light only turns on if all relatively moving observers agreed that the signal (sound or light) arrived simultaneously. This is not true.0 -
How is that? If the speed of sound is constant relative to the medium through which it travels, then shouldn't the sound waves arrive at the midpoint simultaneously in one reference frame but not in the other?
First, I should make clear that there was a typo in my previous post. I meant to type "on", not "off". I.e. Both versions of the thought experiment have a light switching on.
Second, there is no point in me entertaining a wild goose chase. So unless you can sort out your misunderstanding with the previous thought experiment, there is no point moving onto another. Especially since the mistake you are making is more or less the same.0 -
It isn't an assumption, its a prescription; we are perfectly entitled to prescribe such a light system, as dlouth, I think it was, prescribed earlier.citrus burst wrote: »The assumption you made is that the light only turns on if all relatively moving observers agreed that the signal (sound or light) arrived simultaneously. This is not true.0 -
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There is a fundamental difference between the propagation of light and sound, making the two cases quite different.First, I should make clear that there was a typo in my previous post. I meant to type "on", not "off". I.e. Both versions of the thought experiment have a light switching on.
Second, there is no point in me entertaining a wild goose chase. So unless you can sort out your misunderstanding with the previous thought experiment, there is no point moving onto another. Especially since the mistake you are making is more or less the same.
It might be easier just to answer one question: is the speed of sound constant relative to the medium through which it travels?0 -
It isn't an assumption, its a prescription; we are perfectly entitled to prescribe such a light system, as dlouth, I think it was, prescribed earlier.
It is a frame-dependent prescription. As I have explained before: According to some frames, the light will activate if the retinas are struck simultaneously. According to other frames, the light will activate if the retinas are struck in a specific order.0 -
No, this is quite different. The point you were making before is that all frames agree that the signal reaches the CPU, or the point that is midway between the rods, simultaneously; here, the sound signals don't reach that point simultaneously according to relatively moving frames.It is a frame-dependent prescription. As I have explained before: According to some frames, the light will activate if the retinas are struck simultaneously. According to other frames, the light will activate if the retinas are struck in a specific order.
We can prescribe a light system, as dlouth did, where the light only works if it is struck simultaneously; only this time by the sound waves.0 -
No, this is quite different. The point you were making before is that all frames agree that the signal reaches the CPU, or the point that is midway between the rods, simultaneously; here, the sound signals don't reach that point simultaneously according to relatively moving frames.
We can prescribe a light system, as dlouth did, where the light only works if it is struck simultaneously; only this time by the sound waves.
I have told you over and over and over and over that all observers agree on all co-incident events (events that occur at the same place and time). So all frames agree that the sound signals reach the centre point, (cpu or light).0 -
The speed of sound is constant in the medium through which it travels, isn't it; or, it's constant relative to the medium it travels through.I have told you over and over and over and over that all observers agree on all co-incident events (events that occur at the same place and time). So all frames agree that the sound signals reach the centre point, (cpu or light).
Given this fact we, can we not deduce that only simultaneous lightning strikes, which trigger the sound emitters, could possibly result in the simultaneous meeting of the sound waves at a location midway between the emitters; where the emitters and the midpoint are at rest relative to the air through which the sound travels?0 -
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The speed of sound is constant in the medium through which it travels, isn't it; or, it's constant relative to the medium it travels through.
Given this fact we, can we not deduce that only simultaneous lightning strikes, which trigger the sound emitters, could possibly result in the simultaneous meeting of the sound waves at a location midway between the emitters; where the emitters and the midpoint are at rest relative to the air through which the sound travels?
This has already been answered by myself previously. Remember what I said about the signals travelling through the wire? Remember how I asked you to do the Lorentz transformations to see how signals travelling at less than the speed of light (like sound) behave in a relativistic setting?
If you have difficulty with the Lorentz transformations, say so. I will gladly help you.0 -
Aaah, my apologies; I was taking the speed of the signals from the retinae to the CPU to be the speed of light, for the sake of convenience. If you don't mind and have the time, I would be interested in seeing how the LTs work for the case in hand, of the propagation of the sound waves.This has already been answered by myself previously. Remember what I said about the signals travelling through the wire? Remember how I asked you to do the Lorentz transformations to see how signals travelling at less than the speed of light (like sound) behave in a relativistic setting?
If you have difficulty with the Lorentz transformations, say so. I will gladly help you.
Also, is the speed of sound not constant relative to the medium through which it travels; that is, is the speed of sound in air a constant?0 -
On the previous point, about the discordant experiences with light; essentially, the issue as I see it is, the physical process that is my body processing photons, which make physical contact with my retinae, and my brain generating the resultant experiences, remains unchanged; it is the same for all photons which make physical contact with my retinae; even if relatively moving observers disagree over how the body processes them, they will agree that the body processes all photons, which make physical contact with my retinae, the same. Therefore, if photons make physical contact with my retinae in two different orders it should, physically, result in my brain generating two different experiences.
Essentially, stimuli making physical contact with the body in two different orders, should result in the body physically generating two different experiences; given that the physicality of the ordering doesn't matter. The relatively moving observers would still disagree over how the body processes them.
The time, as given by clocks, shouldn't matter either; if the photons make physical contact in two different orders, it should result in the body physically generating two different experiences.
EDIT: it might be helpful to look at the issue in the following way, by posing the question, will Albert's brain functioning change depending on his physical location; that is, will the physical processes of his body and brain, while he is standing on the platform, be different from what they would if he was located on the train?
The reason being, if Albert were located on the train and photons made physical contact with his retinae in the order of one first, then the other, his brain would generate an ordered experience.0 -
On the previous point, about the discordant experiences with light; essentially, the issue as I see it is, the physical process that is my body processing photons, which make physical contact with my retinae, and my brain generating the resultant experiences, remains unchanged; it is the same for all photons which make physical contact with my retinae; even if relatively moving observers disagree over how the body processes them, they will agree that the body processes all photons, which make physical contact with my retinae, the same. Therefore, if photons make physical contact with my retinae in two different orders it should, physically, result in my brain generating two different experiences.
Essentially, stimuli making physical contact with the body in two different orders, should result in the body physically generating two different experiences; given that the physicality of the ordering doesn't matter. The relatively moving observers would still disagree over how the body processes them.
The time, as given by clocks, shouldn't matter either; if the photons make physical contact in two different orders, it should result in the body physically generating two different experiences.
EDIT: it might be helpful to look at the issue in the following way, by posing the question, will Albert's brain functioning change depending on his physical location; that is, will the physical processes of his body and brain, while he is standing on the platform, be different from what they would if he was located on the train?
The reason being, if Albert were located on the train and photons made physical contact with his retinae in the order of one first, then the other, his brain would generate an ordered experience.
The core problem I see is you are not starting your train of thought with the Lorentz transformations. By trying to intuitively construct what is going on with thought experiments and intuition, errors will repeatedly slip in, because no matter how diligent you think you are, the fact that relativity posits relationships between observers that are completely alien to common sense means your intuition will betray you. Maybe smaller steps need to be taken, and built upon.
Currently, we have a complicated measurement apparatus (retinas and a cpu, or retinas and a light, or retinas and a complex biological brain belonging to Albert). Let's replace this complicated apparatus with a simpler one: Two clocks where the retinas used to be. When they are struck, they stop ticking. So a measure of simultaneity that used to be "Do the retinas send a signal processed by a complex brain that generates the experience of simultaneous blindness" is replaced by "Do the clocks stop with the same reading on their faces". If the clocks stop with the same time reported on each clock, the system will report simultaneous strikes. If the clocks don't, then non-simultaneous strikes.
Here is my question to you: Do you accept that, even though different observers will disagree over whether or not the clocks were struck at the same time, all observers will agree with what the clock apparatus reports. I.e. if one observer sees that both clocks report the same time, all observers will agree. To stress it even further: Even though different observers disagree over simultaneity, all observers agree with what is reported by that particular system.
This is not a trick question, I am genuinely trying to see where we can start from.I would be interested in seeing how the LTs work for the case in hand, of the propagation of the sound waves
Sure. I will throw the results up when I get a chance (probably later this evening). They will answer your question about whether or not the speed of sound, relative to the medium, is isotropic in all reference frames (the answer is no, due to time dilation effects across different paths).0 -
Aaah, my apologies; I was taking the speed of the signals from the retinae to the CPU to be the speed of light, for the sake of convenience. If you don't mind and have the time, I would be interested in seeing how the LTs work for the case in hand, of the propagation of the sound waves.
Let the speed of sound be [latex]v[/latex]. It doesn't matter what the speed is really. The same calculations apply to electrical signals. The important thing is that the speed is the same from either detector is the same.
Frame [latex]S[/latex]:
If you imagine that we have the two detectors in the rest frame [latex]S[/latex] at positions [latex]$x_{L}=-x$[/latex] and [latex]$x_R=x$[/latex] either side of the CPU which is at the origin in that frame. The speed of the signal is [latex]v \le c[/latex]. So at time [latex]t=0[/latex], signals travel at respective velocities [latex]v_L=v[/latex] and [latex]v_R=-v[/latex] and arrive at the CPU at [latex]t_C=x/v[/latex].
So we essentially have three spacetime events: [latex]E_{L}=\left(-x,\,0\right) [/latex], [latex]E_{R}=\left(x,\,0\right) [/latex] and [latex]E_{C}=\left(0,\, x/v\right)[/latex].
Frame [latex]S^\prime[/latex].
Frame [latex]S^\prime[/latex] is moving at speed [latex]-V[/latex] relative to frame [latex]S[/latex]. [edit: changed direction of V]
Applying the Lorentz transformation, the three events in [latex]S^{\prime}[/latex] are then [latex]E_{L}^{\prime}=\left(-\gamma x,\,-\gamma x/v\right)[/latex], [latex]E_{R}^{\prime}=\left(\gamma x,\,\gamma x/v\right)[/latex] and [latex]E_{C}^{\prime}=\left(-\gamma Vx/v,\,\gamma x/v\right)[/latex]. Note that the time coordinates for [latex]E_{L}^{\prime}[/latex] and [latex]E_{R}^{\prime}[/latex] are different: [latex]-\gamma x/v\neq\gamma x/v[/latex]. In frame [latex]S^{\prime}[/latex] the signals are detected at different times at the light detectors.
So the question is how is it that they reach the point [latex]x_C^{\prime}=-\gamma Vx/v[/latex] at the same time [latex]t_C^{\prime}=\gamma x/v[/latex]?
The key thing is that velocities are also transformed. Signals travel from detectors towards CPU at [latex]v_{L}^{\prime}=\left(V+v\right)/\left(1+vV/c^{2}\right)[/latex]and [latex]v_{L}^{\prime}=\left(V-v\right)/\left(1-vV/c^{2}\right).[/latex]Note that the absolute values of these velocities are different. The signals do not travel at the same speeds towards the CPU.
The signal is detected by the left detector at time [latex]t_{L}^{\prime}=-\gamma x/v[/latex]. It travels at [latex]v_{L}^{'}[/latex] velocity a distance of [latex]x_{C}^{'}-x_{L}^{\prime}[/latex]. Therefore the time at which it reaches the CPU is [latex]t_{C}^{\prime}=t_{L}^{\prime}+\left(x_{C}^{'}-x_{L}^{\prime}\right)/v_{L}^{'}[/latex]. If we do the algebra we find that [latex]t_{C}^{\prime}=\gamma x/v[/latex], which is exactly what was predicted by the Lorentz transformation applied to [latex]E_{C}[/latex]. We can do the same thing for the other detector on the right hand side: [latex]t_{C}^{\prime}=t_{R}^{\prime}+\left(x_{C}^{'}-x_{R}^{\prime}\right)/v_{R}^{'}[/latex] and again we get the same result: [latex]t_{C}^{\prime}=\gamma x/v[/latex]. Thus signals arrive simultaneously at the CPU even though they are detected by the detectors at different times in frame [latex]S^\prime[/latex].
Some general observations: Every thing predicted by special relativity is predicted mathematically. If you are trying to establish an inconsistency about special relativity the inconsistency must arise from the mathematics since it is a mathematical theory.
For example if it were shown that in frame [latex]S^\prime[/latex] the signals arrived at the CPU at two different times then we would have found an inconsistency in the theory since this would have indicated the CPU firing in one frame but not firing in the other.
What does not demonstrate an inconstancy is you saying that although the mathematics says one thing, "physically" something else should be happening according to your intuition of the situation. This is false reasoning because your intuition about what should be the case is not something predicted by special relativity in the first place. In fact a lot of commonsense notions have to be abandoned in order for special relativity to work. Yet it solves a very fundamental problem of reconciling electromagnetism with other branches of physics and has withstood all experimental tests within its limits to date.0 -
We can essentially take the complexity out of it by considering whether or not the physical functioning of the brain will be the same regardless of it's physical location. If it will physically function the same, regardless of where it is located, then the complexity doesn't matter.The core problem I see is you are not starting your train of thought with the Lorentz transformations. By trying to intuitively construct what is going on with thought experiments and intuition, errors will repeatedly slip in, because no matter how diligent you think you are, the fact that relativity posits relationships between observers that are completely alien to common sense means your intuition will betray you. Maybe smaller steps need to be taken, and built upon.
Currently, we have a complicated measurement apparatus (retinas and a cpu, or retinas and a light, or retinas and a complex biological brain belonging to Albert).
I'm working on the presumption that Albert's brain physically functions the same, regardless of whether he is on the platform or on the train; that is to say that the underlying physical processes are unaffected by how they are labeled.
The issue, then, is that if Albert were on board the train and photons made physical contact with his eyes in the order of one first, then the other, his body would process them and his brain would generate an ordered experience. However, the contention is that this will not be the case for photons which make physical contact with his retinae, in the same order while he is standing on the embankment.
This is where the physical photons which make physical contact with his retinae come from the same physical lightning strikes, and where the physical ordering of the events doesn't matter.
The only piece of intuition there is that Albert's brain will physically function the same on the train as on the embankment; if that is incorrect, then relativity must suggest that his brain will function differently depending on its physical location.
I do agree that, according to relativity, the observers will agree on the time shown by each clock; but, I don't agree with the contention that the same time reading on a clock implies simultaneity, because this would only be true for synchronised clocks; the same time reading on clocks which are not synchronised implies non-simmultaneity.Let's replace this complicated apparatus with a simpler one: Two clocks where the retinas used to be. When they are struck, they stop ticking. So a measure of simultaneity that used to be "Do the retinas send a signal processed by a complex brain that generates the experience of simultaneous blindness" is replaced by "Do the clocks stop with the same reading on their faces". If the clocks stop with the same time reported on each clock, the system will report simultaneous strikes. If the clocks don't, then non-simultaneous strikes.
Here is my question to you: Do you accept that, even though different observers will disagree over whether or not the clocks were struck at the same time, all observers will agree with what the clock apparatus reports. I.e. if one observer sees that both clocks report the same time, all observers will agree. To stress it even further: Even though different observers disagree over simultaneity, all observers agree with what is reported by that particular system.
This is not a trick question, I am genuinely trying to see where we can start from.
Cheers.Sure. I will throw the results up when I get a chance (probably later this evening). They will answer your question about whether or not the speed of sound, relative to the medium, is isotropic in all reference frames (the answer is no, due to time dilation effects across different paths).0 -
I had no idea boards supported LaTex?!Frame [latex]S^\prime[/latex].
Frame [latex]S^\prime[/latex] is moving at speed [latex]V[/latex] relative to frame [latex]S[/latex].
Applying the Lorentz transformation, the three events in [latex]S^{\prime}[/latex] are then [latex]E_{L}^{\prime}=\left(-\gamma x,\,-\gamma x/v\right)[/latex], [latex]E_{R}^{\prime}=\left(\gamma x,\,\gamma x/v\right)[/latex] and [latex]E_{C}^{\prime}=\left(-\gamma Vx/v,\,\gamma x/v\right)[/latex]
I think these should be
[latex]E'_L = \left(-\gamma x,\gamma Vx\right)[/latex]
[latex]E'_R = \left(\gamma x,-\gamma Vx\right) [/latex]
[latex]E'_C = \left(-\gamma V x/v ,\gamma x/v\right)[/latex]0 -
Yeah, I tend to think of the moving frame as the one with the stuff to be measured and one from which the observations are made as being at rest. I've changed my post so that [latex]-V[/latex] has been substituted for [latex]V[/latex] and I think it now works.I had no idea boards supported LaTex?!
I think these should be
[latex]E'_L = \left(-\gamma x,\gamma Vx\right)[/latex]
[latex]E'_R = \left(\gamma x,-\gamma Vx\right) [/latex]
[latex]E'_C = \left(-\gamma V x/v ,\gamma x/v\right)[/latex]0 -
Roosh, would you agree that regardless of the complexity of Albert's brain, the assumption has to be made that we're dealing with a physical object with observable characteristics that can be modeled and measured by observers moving with velocities relative to the brain?
If so, what then is the simplest setup that can be imagined that can demonstrate the alleged inconsistencies?
If not, why do you think that Albert's brain might be different to an observable physical system?0 -
I would agree that we are dealing with a physical object which could, theoretically, be modeled by different observers.Roosh, would you agree that regardless of the complexity of Albert's brain, the assumption has to be made that we're dealing with a physical object with observable characteristics that can be modeled and measured by observers moving with velocities relative to the brain?
If so, what then is the simplest setup that can be imagined that can demonstrate the alleged inconsistencies?
If not, why do you think that Albert's brain might be different to an observable physical system?
We can negate the issue of complexity simply by addressing the question of whether or not the physical processes, of the system, will operate the same, regardless of its physical location; that is, will Albert's brain physically function differently on the train than it will on the platform? In this manner we can hypothesise the most complex possible system, or the least complex possible system, as that should be sufficient for addressing our question.
If Albert were located on the train and the photons made physical contact with his eyes, in the order of one first then the other, his body, or brain, would generate an ordered experience. However, when photons make physical contact with his retinae, while he is standing on the embankment, in the order of one first then the other, his brain will not generate an ordered experience. This would seem to suggest that the physical operations of Albert's brain, or his body as a whole, functions differently depending on his physical location.0 -
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SR suggests that the physical location of the system should not make any difference. The difference arises when spacetime events as measured by one frame are measured by another.I would agree that we are dealing with a physical object which could, theoretically, be modeled by different observers.
We can negate the issue of complexity simply by addressing the question of whether or not the physical processes, of the system, will operate the same, regardless of its physical location; that is, will Albert's brain physically function differently on the train than it will on the platform? In this manner we can hypothesise the most complex possible system, or the least complex possible system, as that should be sufficient for addressing our question.
If Albert were located on the train and the photons made physical contact with his eyes, in the order of one first then the other, his body, or brain, would generate an ordered experience. However, when photons make physical contact with his retinae, while he is standing on the embankment, in the order of one first then the other, his brain will not generate an ordered experience. This would seem to suggest that the physical operations of Albert's brain, or his body as a whole, functions differently depending on his physical location.
However is conscious experience a spacetime event? It is only available to the system having the experience itself? Does it even mean anything to talk about conscious experience in conjunction with different reference frames?
This is why I tried to introduce the simpler system of the two light detectors and a CPU in the middle which flashes when signals from the light detectors occur simultaneously. Why is this not sufficient to demonstrate the inconsistency you believe occurs?
What is your basis for believing that Albert's brain might function in a fundamentally different way?0 -
Yeah, I tend to think of the moving frame as the one with the stuff to be measured and one from which the observations are made as being at rest. I've changed my post so that [latex]-V[/latex] has been substituted for [latex]V[/latex] and I think it now works.
The problem isn't specifically with V, it's how you're transforming the time coordinate. [latex]E'_C[/latex] and [latex]E'_R[/latex] are separated by a timelike interval, but you've transformed them so that they are now separated by a spacelike interval. I.e. In S', you have the two events occurring at the same time ([latex]\gamma x/v[/latex]) which would be impossible under the Lorentz transformations.0 -
Thanks Morbert. You are right. Didn't notice that. I'm going to have another go when I have a bit of time.0
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There appears to be two schools of thought when it comes to conscious experience; one, the materialist paradigm, suggests that conscious experience is nothing more than a by-product of the machinations of the brain; in this sense, conscious experience wouldn't be reducible to a single spacetime event, but would be reducible to a number of spacetime events. The other school of thought appears to be that consciousness is "metaphysical".SR suggests that the physical location of the system should not make any difference. The difference arises when spacetime events as measured by one frame are measured by another.
However is conscious experience a spacetime event? It is only available to the system having the experience itself? Does it even mean anything to talk about conscious experience in conjunction with different reference frames?
For the point in question, however, I don't think it matters whether or not conscious experience is a spacetime event; the point being made was that, when we take what relativity says about the physical world, and apply it to the physical world, that it gives rise to a paradox; that might be a physical paradox as opposed to a mathematical one. It isn't necessarily being said that relativity, as a closed system, is paradoxical or self-contradictory, in a mathematical sense, but rather, when it is applied to the physical world it would appear to suggest a paradox should arise.
Would you agree that if Albert's brain generates an ordered experience on the train, when photons make physical contact with his retinae in the order of one first, then the other, that his brain should generate a similar experience on the platform, if photons make physical contact with his eyes in the order of one first then the other; if there is no difference in how his brain functions between different physical locations and there is no difference in the physicality of the photons which strike his retinae?
You may have answered your own question above, by suggesting the issue lies in the consciousness of the system.This is why I tried to introduce the simpler system of the two light detectors and a CPU in the middle which flashes when signals from the light detectors occur simultaneously. Why is this not sufficient to demonstrate the inconsistency you believe occurs?
I'm not suggesting it does, I'm asking if relativity says it does. If photons which make physical contact with Albert's retinae in the order of one first then the other lead to Albert's brain generating an ordered experience, on the train, then unless Albert's brain functions differently, photons which make physical contact in a given order on the platform should also lead to his brain generating an ordered experience. If that isn't the case, then it suggests that Albert's brian physically functions differently, depending on its physical location.What is your basis for believing that Albert's brain might function in a fundamentally different way?0 -
I do agree that, according to relativity, the observers will agree on the time shown by each clock; but, I don't agree with the contention that the same time reading on a clock implies simultaneity, because this would only be true for synchronised clocks; the same time reading on clocks which are not synchronised implies non-simmultaneity.
So, to clarify, we have a physical system which receives input in the form of two photons striking it, and reports "yes" or "no" the the question of "Did the physical strikes occur simultaneously?". And you accept that just because different observers disagree over whether or not the physical strikes are simultaneous doesn't mean the system in question should paradoxically produce two mutually exclusive reports?0 -
The system doesn't report "yes" or "no", the times on the clocks are what is reported; only if the clocks are synchronised does it imply that the events are simultaneous.So, to clarify, we have a physical system which receives input in the form of two photons striking it, and reports "yes" or "no" the the question of "Did the physical strikes occur simultaneously?". And you accept that just because different observers disagree over whether or not the physical strikes are simultaneous doesn't mean the system in question should paradoxically produce two mutually exclusive reports?
To refer to the illustration of the point above; if Albert were located on the train and the photons, from the lightning strikes, struck his retinae in the order of one first then the other, his body would process them and his brain would generate an ordered experience; if Albert's brain functions the same on the platform as it does on the train, then if the photons, from the same lightning strikes, strike his retinae in the order of one first, then the other is brain should generate an ordered experience.
However, the contention appears to be that this isn't the case.0 -
The system doesn't report "yes" or "no", the times on the clocks are what is reported; only if the clocks are synchronised does it imply that the events are simultaneous.
So you are saying the system isn't necessarily reporting any real simultaneity, because whether or not the system reports the photon strikes as simultaneous depends on whether or not the clocks are synchronised?0 -
There should be no difference, I agree.Would you agree that if Albert's brain generates an ordered experience on the train, when photons make physical contact with his retinae in the order of one first, then the other, that his brain should generate a similar experience on the platform, if photons make physical contact with his eyes in the order of one first then the other; if there is no difference in how his brain functions between different physical locations and there is no difference in the physicality of the photons which strike his retinae?
However we need to recognise the implicit frames of reference involved in your statement. The first is a frame of reference in which the train is at rest (or a frame moving with the train). The second is a frame of reference in which the platform is at rest. We're really talking about two separate scenarios involving frames in which Albert is at rest and we can expect things to happen in the same way in both these frames.
Can you point out the paradox?0 -
I don't think anyone would contend that Albert's brain on the train functions differently to how it would function on the platform. Who is contending that?To refer to the illustration of the point above; if Albert were located on the train and the photons, from the lightning strikes, struck his retinae in the order of one first then the other, his body would process them and his brain would generate an ordered experience; if Albert's brain functions the same on the platform as it does on the train, then if the photons, from the same lightning strikes, strike his retinae in the order of one first, then the other is brain should generate an ordered experience.
However, the contention appears to be that this isn't the case.
All SR deals with is how measurements are made of the same system in different reference frames. In the example you have given we have two identical physical systems, clones of Albert, and each has their own implicit reference frame. SR only comes into play when one of these Alberts makes observations of what is happening with the other.
You could also have a single Albert who starts off on the platform and then gets on the train. Will his brain function the same in both cases as far as Albert is concerned? Yes, because when he's on the platform there's an implicit frame associated with him in which he's at rest. When he is on the train there's another implicit frame in which he's also at rest and the earlier one ceases to be relevant. SR is only involved when we have two or more frames from which measurements are made on the same system.0 -
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Is this not what relativity says when it says that the relativity of simultaneity is not physical?So you are saying the system isn't necessarily reporting any real simultaneity, because whether or not the system reports the photon strikes as simultaneous depends on whether or not the clocks are synchronised?
I'm not sure if the system reports "real" simultaneity; the physicality of the ordering would be a separate debate; as would the question of whether or not lightning strikes can occur without an implicit physical ordering, such that the detection of photons from those strikes has to have a physical ordering. But, as mentioned, that would be a separate debate.
What we do know is that Alber's brain generates real experiences based on physical stimuli which make contact with his sensory organs. If he were on the train and photons struck his retinae in the order of one first, then the other then his brain would generate an ordered experience. If the physical functioning of his brain doesn't change depending on it's physical location, then photons which strike his retinae in the order [of one first then the other] should also lead to his brain generating an ordered experienece. Would you agree?0
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