Question on Lorentz transforms and relativity of simultaneity

Morbert

roosh wrote: »

From the perspective of Albert's brain, which is the perspective it processes Albert's expriences from, the distance to the centre is the same for each retina, and the speed that each signal travels at is the same; so, the order in which the physical strikes occur, determines the order in which they reach the centre; that is, according to Albert's brain as it processes photons which physically strike his retinae, while he is standing on the embankment, to generate Albert's experience.

Essentially what you are saying is "the experience a relatively moving observer has, of Albert's brain process...."; what that gives us is the relatively moving observers experience, not Albert's; we want Albert's experience; and Albert's experience is generated by his brain which processes stimuli which physically "strike" his sensory organs; and it processes them in the order the physical strikes occur.

If we say that the photons which strike Albert's retinae, while he is standing on the embankment, and which occur in the given order, is the experience of the relatively moving observer, not of Albert, then the implication is that the photons do not physically strike Albert's retinae while he is standing on the embankment, or that the physical strikes do not occur in the given order, while he is standing on the embankment; because, if they satisfied both of those conditions then they would be part of Albert's experience as an ordered pair of flashes.

That makes absolutely no sense.

It has been explained before that the brain does not process experiences.

It has also been explained to you before that all observers say the signals reach the processing unit simultaneously.

It has also been explained to you before that ordering of events separated by a spacelike interval is not an inherent quality of the system being considered.

roosh

Morbert wrote: »

That makes absolutely no sense.

It has been explained before that the brain does not process experiences.

It has also been explained that the brain processes physical stimuli to generate experiences, such that the generation of experiences is a process carried out by the brain. I'm sure that you're not particularly interested in that semantical argument, though.

Morbert wrote: »

It has also been explained to you before that all observers say the signals reach the processing unit simultaneously.

And it has also been explained that the measurements a relatively moving observer makes, of Albert's brain activity, is immaterial; what is material is how Albert's brain processes Albert's experiences; and as far as Albert's brain is concerned the distance from each retinae to the processing centre is the same, and the speed at which the signals travel is the same, so the arrival of the signals at the processing centre depends on the order the physical strikes occur at the retinae.

Morbert wrote: »

It has also been explained to you before that ordering of events separated by a spacelike interval is not an inherent quality of the system being considered.

And it doesn't need to be; just like you and I, Albert has ordered experiences, despite the fact that the ordering is not an inherent quality of the system; like us, Albert has experienced flashes of light which occur in the order of one first then the other, despite the ordering not being physical. He has these ordered experiences because photons physically strike his retinae, while he is standing on the embankment, and they do so in a given order.

roosh

dlouth15 wrote: »

You are throwing in a lot of unnecessary stuff here. It is very simple really.

Ignore frames of reference and Albert's brain and all that other complexity for the moment. You will note that I don't mention any of this in my question. Forget you ever heard about special relativity, Lorenz transformations and everything else. We will bring the complexity back later.

Now: the question basically was that the central processing unit determines simultaneity based on the arrival of signals from detectors. If the signals arrive simultaneously then the light goes on.

Very simply do you agree with that?

Yes.

Do you agree that, from the "perspective" of the system - which is the "perspective" it processes the signals from - that the distance, from receptor to the central unit, is the same from both receptors, and the speed that the signals travel at is the same along both paths?

dlouth15

roosh wrote: »

Yes.

Do you agree that, from the "perspective" of the system - which is the "perspective" it processes the signals from - that the distance, from receptor to the central unit, is the same from both receptors, and the speed that the signals travel at is the same along both paths?

Thanks for answering that question.

Now to answer your question, yes. The two receptors send a signal at the same time and they travel with the same speed v to arrive simultaneously at the central processing unit which then processes the two signals and the light goes on.

I have a further couple of questions if you don't mind.

If we stick with the idea that we're ignoring special relativity, Lorentz transformations and the like; imagine this setup with the two receptors and the central processing unit is moving at speed V relative to some stationary observer. Imagine that the light still strikes the two receptors simultaneously and travels towards the central processing unit. (remember we're not bothering with relativity at this point).

Would you agree that from the point of view of the observer, the light hits the two receptors simultaneously, the signal travels from one receptor towards the moving central processing unit at speed V+v and from the second processing unit at speed V-v. Similarly the distances as measured by the observer will also be different as from the time the simultaneous photons hits the receptors to when the signals are received the central processing unit will have moved.

Here's the important question: would you agree that the description from the observers point of view is every bit as valid (every bit as physical) as the description from an observer moving with the setup? Yes, some of the speeds and distances are different but essentially the same physical process is being described.

roosh

dlouth15 wrote: »

Thanks for answering that question.

no need to thank me, I'm genuinely just putting forward my understanding and debating on that basis.

dlouth15 wrote: »

Now to answer your question, yes. The two receptors send a signal at the same time and they travel with the same speed v to arrive simultaneously at the central processing unit which then processes the two signals and the light goes on.

Would you agree that this is how the system processes all photons which physically strike the receptors; that where the physical strikes occur in a different order the light will not go on?

dlouth15 wrote: »

I have a further couple of questions if you don't mind.

Not at all; as I say, I'm genuinely just debating my own understanding, be it right or wrong - I obviously think its right, otherwise it wouldn't form part of my understanding.

dlouth15 wrote: »

If we stick with the idea that we're ignoring special relativity, Lorentz transformations and the like; imagine this setup with the two receptors and the central processing unit is moving at speed V relative to some stationary observer.

Without the context of special relativity, what do we mean by "stationary" here?

dlouth15 wrote: »

Imagine that the light still strikes the two receptors simultaneously and travels towards the central processing unit. (remember we're not bothering with relativity at this point).

Would you agree that from the point of view of the observer, the light hits the two receptors simultaneously, the signal travels from one receptor towards the moving central processing unit at speed V+v and from the second processing unit at speed V-v. Similarly the distances as measured by the observer will also be different as from the time the simultaneous photons hits the receptors to when the signals are received the central processing unit will have moved.

Are we talking about the "stationary" observer here; if so, I have a few questions about how he conducts his measurements, only because I can't immediately visualise it.

dlouth15 wrote: »

Here's the important question: would you agree that the description from the observers point of view is every bit as valid (every bit as physical) as the description from an observer moving with the setup? Yes, some of the speeds and distances are different but essentially the same physical process is being described.

I would say that the observers might disagree on the relative velocity between them, because their clocks tick at different rates; I'm not sure how they would measure distances though, because that would involve reflected photons which I think might be affected by the implications of what is meant by "stationary" above.

Morbert

roosh wrote: »

And it has also been explained that the measurements a relatively moving observer makes, of Albert's brain activity, is immaterial; what is material is how Albert's brain processes Albert's experiences; and as far as Albert's brain is concerned the distance from each retinae to the processing centre is the same, and the speed at which the signals travel is the same, so the arrival of the signals at the processing centre depends on the order the physical strikes occur at the retinae.

That is not an explanation. That is a falsehood. Henry does not agree with Albert when he says the speed of the signal is the same in both "wires" connecting the retinas to the processing unit. He says it is faster in one than in the other. Signal speed is a frame-dependent quantity, not an inherent physical quality of the system. Hence, Henry's description of events is no more or less valid than Albert's.

And it doesn't need to be; just like you and I, Albert has ordered experiences, despite the fact that the ordering is not an inherent quality of the system; like us, Albert has experienced flashes of light which occur in the order of one first then the other, despite the ordering not being physical. He has these ordered experiences because photons physically strike his retinae, while he is standing on the embankment, and they do so in a given order.

And unless you can show that the "given order" is an inherent quality of the system, rather than a reflection of the reference frame used to label events, there is no contradiction.

roosh

Morbert wrote: »

That is not an explanation. That is a falsehood. Henry does not agree with Albert when he says the speed of the signal is the same in both "wires" connecting the retinas to the processing unit. He says it is faster in one than in the other. Signal speed is a frame-dependent quantity, not an inherent physical quality of the system. Hence, Henry's description of events is no more or less valid than Albert's.

That is Henry's experience, not Albert's; Albert's brain processes Albert's experiences from its own perspective, where the distance and speed is the same from both retinae. This is the same in every physical reference frame that Albert might find himself; if Albert were with Henry on the train it would be the same, or if Albert were on a different train moving relative to both Henry and the embankment it would be the same.

Morbert wrote: »

And unless you can show that the "given order" is an inherent quality of the system, rather than a reflection of the reference frame used to label events, there is no contradiction.

It isn't necessary that the "given order" be an inherent quality of the system; like you and I, Albert has had ordered experiences of flashes of light; he has often seen flashes occur in a given order; this despite the fact that the order isn't an inherent quality in the system.

EDIT: He has these ordered experiences because his brain processes photons which physically strike his retinae, to generate his experience; but photons physically striking his retinae doesn't necessarily mean that he will have an ordered experience of them; he has the ordered experience because the physical strikes occur in a given order; without the order being an inherent quality in the system.

Morbert

roosh wrote: »

That is Henry's experience, not Albert's; Albert's brain processes Albert's experiences from its own perspective, where the distance and speed is the same from both retinae. This is the same in every physical reference frame that Albert might find himself; if Albert were with Henry on the train it would be the same, or if Albert were on a different train moving relative to both Henry and the embankment it would be the same.

Again (and again and again), you are losing track of the conversation. Both Albert and Henry use different coordinate labels to describe events. Both descriptions of events agree with what experiences Albert's brain will generate. Both descriptions do not agree with the ordering of events. Neither description is more or less correct than the other. That is all there is to it.

It isn't necessary that the "given order" be an inherent quality of the system; like you and I, Albert has had ordered experiences of flashes of light; he has often seen flashes occur in a given order; this despite the fact that the order isn't an inherent quality in the system.

EDIT: He has these ordered experiences because his brain processes photons which physically strike his retinae, to generate his experience; but photons physically striking his retinae doesn't necessarily mean that he will have an ordered experience of them; he has the ordered experience because the physical strikes occur in a given order; without the order being an inherent quality in the system.

Hence, there is no contradiction, as all observers agree with what Albert's brain will generate, since all observers agree that Albert's brain is stationary with respect to his retinas.

roosh

Morbert wrote: »

Again (and again and again), you are losing track of the conversation. Both Albert and Henry use different coordinate labels to describe events. Both descriptions of events agree with what experiences Albert's brain will generate. Both descriptions do not agree with the ordering of events. Neither description is more or less correct than the other. That is all there is to it.

I'm not losing track at all; in every physical location that Albert finds himself in the universe, be that on a train moving relative to an embankment, or a train moving relative to another train and an embankment, or on an embankment at rest relative to it, his brain will process all photons which physically strike his retinae in the same way; it will process them from its own perspective, not from anyone elses.

From the perspective of Albert's brain, which again, is the perspective it processes Albert's experiences from, the distance and speed for signals to reach the processing centre is the same for both retinae.

To generate Albert's experiences, Albert's brain processes stimuli which physically strike his retinae. Now, Albert's brain regularly generates ordered experiences of such things as flashes of light, the question is, how does it do this? The physical striking of his retinae by physical photons doesn't necessitate an ordered experience, there must be some mitigating factor. We know that mitigating factor is the order in which the photons physically strikes occur - not necessarily the physical order.

S' says the physical photon strikes occur in a given order, so Albert's brian should process an ordered experience.

Morbert wrote: »

Hence, there is no contradiction, as all observers agree with what Albert's brain will generate, since all observers agree that Albert's brain is stationary with respect to his retinas.

The manner in which Albert's brian processes photons which physically strike his retinae is what leads to the paradox.

Morbert

roosh wrote: »

I'm not losing track at all; in every physical location that Albert finds himself in the universe, be that on a train moving relative to an embankment, or a train moving relative to another train and an embankment, or on an embankment at rest relative to it, his brain will process all photons which physically strike his retinae in the same way; it will process them from its own perspective, not from anyone elses.

From the perspective of Albert's brain, which again, is the perspective it processes Albert's experiences from, the distance and speed for signals to reach the processing centre is the same for both retinae.

To generate Albert's experiences, Albert's brain processes stimuli which physically strike his retinae. Now, Albert's brain regularly generates ordered experiences of such things as flashes of light, the question is, how does it do this? The physical striking of his retinae by physical photons doesn't necessitate an ordered experience, there must be some mitigating factor. We know that mitigating factor is the order in which the photons physically strikes occur - not necessarily the physical order.

S' says the physical photon strikes occur in a given order, so Albert's brian should process an ordered experience.

The manner in which Albert's brian processes photons which physically strike his retinae is what leads to the paradox.

From the other thread:

roosh wrote: »

So Albert can't take two physical clocks with him as he boards the train, reset them and use them; and he can't take his trusty metre stick with him? Just as he could theoretically lay out clocks all over the universe to define his frame as being at rest relative to the embankment, he can theoretically take those same clocks, reset them, and use them to define his reference frame as being at rest relative to the train.



There is no disagreement between the reference frames with regard to the motion of either physical observer relative to the other physical observer; there is a disagreement over the order of one physical strike with the other physical strike.

You're saying also saying that the ordering of events is observer dependent in the manner that an observer's perception of beauty is, when it clearly isn't; an observer doesn't use any measuring instruments to measure the beauty of a rainbow; the order of events is measured by making a physical measurement which involves something which is physically instrinsic to the event, the photon.



Again, we know that observers have ordered experiences of events, despite the fact that order is not an intrinsic property of the system; we know that an observers experience is determined by the physical stimuli which "strike" their sensory organs. The striking of the sensory organs alone doesn't necessitate that an observer will have an ordered experience; what necessitates the ordered experience is the order in which the physical strikes occur. Again, this is despite the fact that the ordering is not an intrinsic, physical characteristic of the system.

S' says that the physical retinae strikes occur in the order of one first, then the other; if they do, then Albert's brain should process them in that order, and generate an ordered experience.

You are ignoring what I said. I'll try again.

What you said, above, is untrue. It is untrue because both Albert and Henry agree with what experiences Albert experiences. No contradiction. No paradox. S says Albert's experiences simultaneous strikes as simultaneous. S' says Albert experiences non-simultaneous strikes as simultaneous. Neither is more or less correct.

What you also keep ignoring is this: If spacetime were Newtonian, you would be correct. Since it is Minkowskian, there is no paradox.
http://en.wikipedia.org/wiki/Minkowski_spacetime

[edit]- Here is the salient point in the article. Consider our two events, x and y

Wikipedia wrote:

x chronologically precedes y if y − x is future directed timelike.
x causally precedes y if y − x is future directed null

y-x is spacelike. (As is x-y) Therefore, you cannot say x or y chronologically precedes the other.

roosh

Morbert wrote: »

From the other thread:

You are ignoring what I said. I'll try again.

I love that whenever you say that I am ignoring what you've said, it is usually in a post where you ignore my specific responses to your different points.

You've tried to assert that the measurement of the order of events is not an intrinsic property of the physical events, by likening it to an observers perception of the beauty of a rainbow, or their opinion of a film; but it has been demonstrated how the two are not analogous.

You also seem to be conflating the arbitrary choice of measuring implements, and the resultant units, with the arbitrariness of the physical properties they measure. As I said, Albert doesn't blindly decide which event is first and which is second by drawing straws, this is determined by the physical measurements that the measuring instruments make, of photons which are physically intrinsic to the original events. Albert's choice as to whether to use a banana or a metre stick to measure length, is entirely arbitrary, but the physical photons which are measured, and which are physically intrinsic to the original events are not.

You also assert that Albert will measure a different order because he uses different clocks and measuring sticks, but that isn't necessarily the case. You further assert that they are different because the measurements he makes are different, but that doesn't follow at all. Albert can use the exact same clocks and measuring sticks he was using. This means that the ordering of events isn't intrinsic to the measuring instruments either; I'm just wondering if this can be extended to the arbitrary, mathematical reference frames which are represented by the units of the measuring instruments.

Morbert wrote: »

What you said, above, is untrue. It is untrue because both Albert and Henry agree with what experiences Albert experiences. No contradiction. No paradox. S says Albert's experiences simultaneous strikes as simultaneous. S' says Albert experiences non-simultaneous strikes as simultaneous. Neither is more or less correct.

And this is just a repeat of the same point we've covered; Albert's brain processes Albert's experiences from its own perspective, where the speed and distance is the same for both retinae; it processes his experiences on the basis of stimuli which physically strike his senses, and it processes them in the order the physical strikes occur.

S' says the physical strikes occur in a different order to S, so that should result in two different experiences.

Morbert wrote: »

What you also keep ignoring is this: If spacetime were Newtonian, you would be correct. Since it is Minkowskian, there is no paradox.http://en.wikipedia.org/wiki/Minkowski_spacetime

Minkowski spacetime doesn't change the fact that Albert's brain processes his experiences from its own perspective; Minkowski spacetime is simply the mathematical solution which appears to accommodate the apparent paradox, but it only does so mathematically.

Morbert wrote: »

[edit]- Here is the salient point in the article. Consider our two events, x and y

x chronologically precedes y if y − x is future directed timelike.
x causally precedes y if y − x is future directed null[/QUOTE]


y-x is spacelike. (As is x-y) Therefore, you cannot say x or y chronologically precedes the other.[/QUOTE]
When you say chronologically, what precisely do you mean?

Morbert

roosh wrote: »

I love that whenever you say that I am ignoring what you've said, it is usually in a post where you ignore my specific responses to your different points.

I say you are ignoring what I say because you are ignoring what I say. We will specifically go through what you are ignoring below.

You've tried to assert that the measurement of the order of events is not an intrinsic property of the physical events, by likening it to an observers perception of the beauty of a rainbow, or their opinion of a film; but it has been demonstrated how the two are not analogous.

Here, for example, you ignore what I said previously: The beauty of a rainbow, and the ordering of spacelike events, are extrinsic, unphysical properties. More specifically, the example of a beautiful rainbow was an example of how an unphysical quality can be applied to a physical object. In this manner, it is absolutely an appropriate analogy.

You also seem to be conflating the arbitrary choice of measuring implements, and the resultant units, with the arbitrariness of the physical properties they measure. As I said, Albert doesn't blindly decide which event is first and which is second by drawing straws, this is determined by the physical measurements that the measuring instruments make, of photons which are physically intrinsic to the original events. Albert's choice as to whether to use a banana or a metre stick to measure length, is entirely arbitrary, but the physical photons which are measured, and which are physically intrinsic to the original events are not.

Here, you also ignore what I said previously. Albert's measurement apparatus (In this case, his retinas and his brain, or the simplified model of retinas and a CPU) is absolutely arbitrary. It is no more or less appropriate than Henry's apparatus. Your "drawing straws" statement is irrelevant. You are arguing against a straw man because you are apparently not willing to have the patience to sit down and think your position through.

You also assert that Albert will measure a different order because he uses different clocks and measuring sticks, but that isn't necessarily the case. You further assert that they are different because the measurements he makes are different, but that doesn't follow at all. Albert can use the exact same clocks and measuring sticks he was using. This means that the ordering of events isn't intrinsic to the measuring instruments either; I'm just wondering if this can be extended to the arbitrary, mathematical reference frames which are represented by the units of the measuring instruments.

This, again, tells me you have no idea what you are talking about. You do not even understand the basics of the position you are arguing against. The "assertions" I am making can be found in any basic, elementary textbook on the theory of relativity. For the nth time, I will post the relevant link. Read it very carefully.

http://en.wikipedia.org/wiki/General_covariance
"In theoretical physics, general covariance (also known as diffeomorphism covariance or general invariance) is the invariance of the form of physical laws under arbitrary differentiable coordinate transformations. The essential idea is that coordinates do not exist a priori in nature, but are only artifices used in describing nature, and hence should play no role in the formulation of fundamental physical laws."

If Albert moves onto the train, his clocks and rulers, whether or not they are the same clocks and rulers, will be employed differently. The manner in which the clocks and rulers are employed, should play no role in the formulation of what is physically happening on a fundamental level. Do you understand this? Do you understand that the ordering of events in terms of the coordinate time of Henry's clocks, or Albert's clocks, or Albert's brain should play no role in the formulation of what is physically happening on a fundamental level. You, whether you understand it, or admit it, or not, are using coordinate frames to decide what is physically happening.

And this is just a repeat of the same point we've covered; Albert's brain processes Albert's experiences from its own perspective, where the speed and distance is the same for both retinae; it processes his experiences on the basis of stimuli which physically strike his senses, and it processes them in the order the physical strikes occur.

And to repeat my response forever and ever: The "perspective of Albert's brain" is no more or less valid than the perspective of Henry's brain. When Alert measures the speed of the signals to be the same, that does not mean that they are physically the same, because the coordinate labels employed by Albert should play no role in formulating the fundamental physics of the scenario.

S' says the physical strikes occur in a different order to S, so that should result in two different experiences.

No it shouldn't. S' says the physical strikes occur in a different order, but that the measurement apparatus that is Albert's brain, whether it is taken to be a single cpu or a complex web of neurons, will measure the strikes as occurring simultaneously. I'll repeat it again, because you consistently, repeatedly, exasperatingly, keep... ignoring... this... fact: S' "says" that Albert's brain will measure the strikes to be simultaneous. Therefore S' does not say the experience should be one of two strikes occurring non-simultaneously.

This is what kills me. We explicitly showed you, using a toy model of retinas, some wire, and a CPU, that S' says Albert's brain will measure the strikes to be simultaneous. We took the time to explain to you why the same holds if we replace the toy model with a realistic brain. Instead of absorbing this information, you instead ignored it.

One more time, to be sure it sinks in: S' says Albert's brain will measure the strikes to be simultaneous. It therefore doesn't make any predictions contrary to the predictions of S with what Albert will experience.

Minkowski spacetime doesn't change the fact that Albert's brain processes his experiences from its own perspective; Minkowski spacetime is simply the mathematical solution which appears to accommodate the apparent paradox, but it only does so mathematically.

Minkowski spacetime is not a mathematical solution to accommodate a paradox. It is a statement about the physical structure of the universe. Your assertion that is is mathematical can be dismissed out of hand, as is presupposes a presentist interpretation of relativity.

When you say chronologically, what precisely do you mean?

In the simplest terms: x chronologically precedes y means x happens before y according to all possible frames of reference.

roosh

Morbert wrote: »

I say you are ignoring what I say because you are ignoring what I say. We will specifically go through what you are ignoring below.

Again, it's not me ignoring what you are saying; I'm engaging with what you are saying and providing responses on that basis.

Morbert wrote: »

Here, for example, you ignore what I said previously: The beauty of a rainbow, and the ordering of spacelike events, are extrinsic, unphysical properties. More specifically, the example of a beautiful rainbow was an example of how an unphysical quality can be applied to a physical object. In this manner, it is absolutely an appropriate analogy.

And here you ignore my response explaining why the cases are sufficiently different to mean that they are not analagous. The point you are making about unphysical qualities being applied to physical objects would be analagous to how language, or linguistic labels are used to refer to physical objects. Bear in mind that the assertion, that the order is extrinsic, is also being questioned; you tried to demonstrate its extrinsic nature by using the rainbow analogy, but it has been clearly pointed out how the two are sufficiently different for the analogy not to demonstrate your assertion; that the order is extrinsic. But to clarify why the analogy doesn't work, I'll outline it again.

The ordering of events is markedly different to an observers perception of beauty, or their opinion of a film; an observer's opinion of a film depends on their past experiences, the order they ascribe to events is not. The same observer would disagree about the order of events, depending on their location, whereas if an observer watched the same movie in two identical theatres they would not change their opinion of the movie. Where two observers, who watched the movie in the same theatre, might disagree about how good the movie is, they should not disagree about the order of events (as long as they were at rest relative to each other). This means that the ordering of events isn't intrinsic to the observer as their opinions on a movie are.

They're also not intrinsic to the measuring instruments, because the same instruments can measure a different order. The measuring instruments are used to measure physical properties; they measure the photons which physically strike and those photons are physically intrinsic to the original events.

We can only measure what is physical, and while we measure the physical photon strikes we conclude that they occur in a given order; but the detection of physical photon strikes only allows us to conclude that the photons are physical and the striking events are physical. How do we deduce the order of the strikes, if there is nothing physical about the order?

Morbert wrote: »

Here, you also ignore what I said previously. Albert's measurement apparatus (In this case, his retinas and his brain, or the simplified model of retinas and a CPU) is absolutely arbitrary. It is no more or less appropriate than Henry's apparatus. Your "drawing straws" statement is irrelevant. You are arguing against a straw man because you are apparently not willing to have the patience to sit down and think your position through.

Albert's brain isn't as arbitrary as Henry's apparatus, when it comes to generating Albert's experiences. In this case, Albert's brain definitely is more appropriate.

Again, the drawing straws statement pertains to the ascription of an order to the events; this is not how the order of events is ascribed, so it isn't arbitrary; the instruments used to measure the order might be arbitrary, and the units might be as well but that doesn't mean that the order is; it means that the units the order is expressed in are.

Morbert wrote: »

This, again, tells me you have no idea what you are talking about. You do not even understand the basics of the position you are arguing against. The "assertions" I am making can be found in any basic, elementary textbook on the theory of relativity. For the nth time, I will post the relevant link. Read it very carefully.

My replies were directly to the statements you had made and the assertions weren't the same as what you've posted below; you said that Albert uses different clocks on the train, but that isn't necessarily the case; you said that they are different because they make different measurements, but that isn't necessarily the case; you have now changed that to "they are employed differently". It might be worth looking at your own statements first.

Morbert wrote: »

http://en.wikipedia.org/wiki/General_covariance
"In theoretical physics, general covariance (also known as diffeomorphism covariance or general invariance) is the invariance of the form of physical laws under arbitrary differentiable coordinate transformations. The essential idea is that coordinates do not exist a priori in nature, but are only artifices used in describing nature, and hence should play no role in the formulation of fundamental physical laws."

If Albert moves onto the train, his clocks and rulers, whether or not they are the same clocks and rulers, will be employed differently. The manner in which the clocks and rulers are employed, should play no role in the formulation of what is physically happening on a fundamental level. Do you understand this? Do you understand that the ordering of events in terms of the coordinate time of Henry's clocks, or Albert's clocks, or Albert's brain should play no role in the formulation of what is physically happening on a fundamental level. You, whether you understand it, or admit it, or not, are using coordinate frames to decide what is physically happening.

This doesn't address the issue, because it doesn't contradict anything I've said. The clocks shouldn't play a role in the formulation of what is physically happening at a fundamental level; other than to make measurements. And that is what I have said, the same clocks can be used and will arrive at different measurements, so the ordering of events isn't intrinsic to the clocks.

Bear in mind, I'm not the one trying to distinguish between the clocks as a reason for the order of events being different, by saying a) they're different clocks, b) they're different because they make different measurements, and then c) they are employed differently.


Again, the ordering of events isn't intrinsic to the observer, in the manner opinion of a film is; indeed, it isn't intrinsic to the observer at all, because the same observer would arrive at different conclusions depending on his location. The ordering of events isn't intrinsic to the measuring instruments because the same instruments can measure a different order.

The measuring instruments measure physical properties, they detect physical photons which are physically intrinsic to the original events; but the detection of physical photons doesn't allow us to conclude anything about the order of events, it only allows us to conclude that the photons are physical; how is it then, that we measure the order of events?

Morbert wrote: »

And to repeat my response forever and ever: The "perspective of Albert's brain" is no more or less valid than the perspective of Henry's brain. When Alert measures the speed of the signals to be the same, that does not mean that they are physically the same, because the coordinate labels employed by Albert should play no role in formulating the fundamental physics of the scenario.

When it comes to generating Albert's experiences, Albert's brain is, most definitely, more valid than Henry's brain.

Again, the co-ordinate labels don't play a role in the formulation of the fundamental physical events, Albert's physical brain is described by the co-ordinate labels and from the perspective of Albert's brain - which is the perspective it generates Albert's experiences from - the speed is the same from both retinae.

Morbert wrote: »

No it shouldn't. S' says the physical strikes occur in a different order, but that the measurement apparatus that is Albert's brain, whether it is taken to be a single cpu or a complex web of neurons, will measure the strikes as occurring simultaneously. I'll repeat it again, because you consistently, repeatedly, exasperatingly, keep... ignoring... this... fact: S' "says" that Albert's brain will measure the strikes to be simultaneous. Therefore S' does not say the experience should be one of two strikes occurring non-simultaneously.

This demonstrates to me that you don't understand the position you are arguing against; I'm not saying that S' says that Albert should have a non-simultaneous experience; in fact, I have acknowledged that S' doesn't say this on numerous occasions.

What S' does say though, is that the physical strikes occur in a given order, while Albert is standing on the embankment; using this information together with what we know about how Albert's brain processes sensory stimuli to generate his experiences, while he is standing on the embankment, we can deduce that, if S' corresponds to physical events, then Albert's brain should generate a non-simultaneous experience; in the physical world, not "in" a mathematical reference frame.

Morbert wrote: »

This is what kills me. We explicitly showed you, using a toy model of retinas, some wire, and a CPU, that S' says Albert's brain will measure the strikes to be simultaneous. We took the time to explain to you why the same holds if we replace the toy model with a realistic brain. Instead of absorbing this information, you instead ignored it.

One more time, to be sure it sinks in: S' says Albert's brain will measure the strikes to be simultaneous. It therefore doesn't make any predictions contrary to the predictions of S with what Albert will experience.

And what kills me is that I have addressed this point repeatedly; the issue doesn't arise between the comparison of the two mathematical descriptions to each other, it arises when we relate the mathematical reference frames back to the physical world.

We're not interested in what Henry says about Albert's experiences, we're interested in what Albert says about Albert's experiences; we are, however, interested in what Henry says about photons which physically strike Albert's retinae, while Albert is standing on the embankment; because we know how Albert's brain processes them to generate Albert's experiences.

Mathematically there is no paradox, physically there is.

Morbert wrote: »

Minkowski spacetime is not a mathematical solution to accommodate a paradox. It is a statement about the physical structure of the universe. Your assertion that is is mathematical can be dismissed out of hand, as is presupposes a presentist interpretation of relativity.

I didn't say it was a solution to accomodate it, I said that it was the solution which does accommodate it.

Whether a block universe or a presentist universe is pre-supposed, Minkowskis formulation is mathematical.

Morbert wrote: »

In the simplest terms: x chronologically precedes y means x happens before y according to all possible frames of reference.

You seem to be using the term "chronology" differently to how it is being used here:

The time ordering of two spacelike separated events is arbitrary, when all inertial frames are taken into account, but for three or more events it is not generally so. We determine the structure of possible time orderings, or chronologies,...

Constraints on chronologies - Shapere & Wilczek
The above seems to suggest that the chronology of events is simply their "time ordering", which, for two "spatially separated" events is also said to be arbitrary, such that:

it's possible to make two spatially separated events appear in any order by choosing to view them from different frames of reference.

SR and the curious physics of chronology

In our case, the "time ordering", or chronology of the events, according to S' is different to the chronology, or "time ordering", of events in S. This would lead us back to the discussion we have been having.


On the same point; are the events not separated by a time-like interval according to S'?

EDIT: just a question on the above point

x chronologically precedes y if y − x is future directed timelike.
x causally precedes y if y − x is future directed null

If we say that x does not chronologically precede y, does that not point to a physically absolute simultaneity, as juxtaposed with the non-physical relativity of simultaneity?

Morbert

roosh wrote: »

And here you ignore my response explaining why the cases are sufficiently different to mean that they are not analagous. The point you are making about unphysical qualities being applied to physical objects would be analagous to how language, or linguistic labels are used to refer to physical objects. Bear in mind that the assertion, that the order is extrinsic, is also being questioned; you tried to demonstrate its extrinsic nature by using the rainbow analogy, but it has been clearly pointed out how the two are sufficiently different for the analogy not to demonstrate your assertion; that the order is extrinsic. But to clarify why the analogy doesn't work, I'll outline it again.

The ordering of events is markedly different to an observers perception of beauty, or their opinion of a film; an observer's opinion of a film depends on their past experiences, the order they ascribe to events is not. The same observer would disagree about the order of events, depending on their location, whereas if an observer watched the same movie in two identical theatres they would not change their opinion of the movie. Where two observers, who watched the movie in the same theatre, might disagree about how good the movie is, they should not disagree about the order of events (as long as they were at rest relative to each other). This means that the ordering of events isn't intrinsic to the observer as their opinions on a movie are.

And that response is absolutely meaningless. It is completely and entirely beside the point. Maybe this is why you think I am ignoring your response. The ordering of events is absolutely relative to the observer. More specifically, it is relative to the set of instruments used to make the measurement. Even more specifically, we can say that the measured order of events will differ between measurement apparatuses as a function of the relative velocity between the apparatuses. This is a fact, and you highlighting some arbitrary difference between simultaneity and the quality of film does nothing to counter that fact.

They're also not intrinsic to the measuring instruments, because the same instruments can measure a different order. The measuring instruments are used to measure physical properties; they measure the photons which physically strike and those photons are physically intrinsic to the original events.

This is also irrelevant. Despite it's irrelevance, I have already told you that, yes, it is not intrinsic to the measurement instruments. It is, however, intrinsic to the relative velocity between those instruments and the objects they are being applied to.

We can only measure what is physical, and while we measure the physical photon strikes we conclude that they occur in a given order; but the detection of physical photon strikes only allows us to conclude that the photons are physical and the striking events are physical. How do we deduce the order of the strikes, if there is nothing physical about the order?

The measuring instruments measure physical properties, they detect physical photons which are physically intrinsic to the original events; but the detection of physical photons doesn't allow us to conclude anything about the order of events, it only allows us to conclude that the photons are physical; how is it then, that we measure the order of events?

Yes, we only measure physical things. But how we measure things, and how those measurements are expressed (I.e. Length, duration, ordering) involves frames of references.

Albert's brain isn't as arbitrary as Henry's apparatus, when it comes to generating Albert's experiences. In this case, Albert's brain definitely is more appropriate.

Absolutely not. That is a bare faced assertion that can be dismissed out of hand. It is antithetical to the very principle of relativity.

My replies were directly to the statements you had made and the assertions weren't the same as what you've posted below; you said that Albert uses different clocks on the train, but that isn't necessarily the case; you said that they are different because they make different measurements, but that isn't necessarily the case; you have now changed that to "they are employed differently". It might be worth looking at your own statements first.

The above is an irrelevant objection to my shorthand description of the clocks. While I'm always happy to clarify, I won't entertain irrelevant digressions. By different clocks, I mean different coordinate measures. Further digressions of this kind will be summarily ignored.

This doesn't address the issue, because it doesn't contradict anything I've said. The clocks shouldn't play a role in the formulation of what is physically happening at a fundamental level; other than to make measurements.

Again, the co-ordinate labels don't play a role in the formulation of the fundamental physical events, Albert's physical brain is described by the co-ordinate labels and from the perspective of Albert's brain - which is the perspective it generates Albert's experiences from - the speed is the same from both retinae.

This absolutely contradicts what you are saying. The ordering of events, i.e. the coordinate time labels of events, plays no role in what is happening at a fundamental level. What you are saying is that they do. You are saying the coordinate time labels generated by the measurement apparatus (Albert's Brain) plays a role in what is happening on a fundamental level.

This demonstrates to me that you don't understand the position you are arguing against; I'm not saying that S' says that Albert should have a non-simultaneous experience; in fact, I have acknowledged that S' doesn't say this on numerous occasions.

What S' does say though, is that the physical strikes occur in a given order, while Albert is standing on the embankment; using this information together with what we know about how Albert's brain processes sensory stimuli to generate his experiences, while he is standing on the embankment, we can deduce that, if S' corresponds to physical events, then Albert's brain should generate a non-simultaneous experience; in the physical world, not "in" a mathematical reference frame.

No. S' says the physical strikes occur in a different order, but that the measurement apparatus that is Albert's brain, whether it is taken to be a single cpu or a complex web of neurons, will measure the strikes as occurring simultaneously. I'll repeat it again, because you consistently, repeatedly, exasperatingly, keep... ignoring... this... fact: S' "says" that Albert's brain will measure the strikes to be simultaneous.

S' says that Albert's brain will measure the strikes to be simultaneous.
S' says that any measurement apparatus that is stationary relative to the poles will measure the strikes to be simultaneous.
S' says that retinas and a single cpu, or a single light detector, or a complex brain, or a convoluted apparatus consisting of elephants, fruit bats, and disgruntled postal employees will measure the strikes to be simultaneous if the apparatus is stationary with respect to the pole.

Therefore... when you say "if [the coordinate times of] S' correspond to physical events, then Albert's brain should generate a non-simultaneous experience", you are dead wrong. You are dead wrong because, while S' says the strikes occurred non-simultaneously, it also says any apparatus stationary with respect to the strikes will measure the strikes to be simultaneous.

<snipping repetition and further irrelevancies>

You seem to be using the term "chronology" differently to how it is being used here:

Constraints on chronologies - Shapere & Wilczek

The above seems to suggest that the chronology of events is simply their "time ordering", which, for two "spatially separated" events is also said to be arbitrary, such that:

SR and the curious physics of chronology

In our case, the "time ordering", or chronology of the events, according to S' is different to the chronology, or "time ordering", of events in S. This would lead us back to the discussion we have been having.

The "time ordering" refers to coordinate time, which is not in the the same context of the "chronological precedence" statements made by Wikipedia.

Also, when they say the ordering of events between three spacelike events might not be arbitrary, they mean that, if you have three events A,B and C, they can appear in the order A,B,C, or C,B,A, or be simultaneous, but some orders like C,A,B, or B,C,A, or B,A,C, are impossible. This is true, but irrelevant to the current conversation.

On the same point; are the events not separated by a time-like interval according to S'?

No. The interval is frame-independent. It is a physical relation, and therefore not implying any frame of reference. So all observers will agree.

EDIT: just a question on the above point
If we say that x does not chronologically precede y, does that not point to a physically absolute simultaneity, as juxtaposed with the non-physical relativity of simultaneity?

In a trivial sense, yes. We can define an absolute simultaneity if we define everything outside the light cones of an event as simultaneous with that event. But this leads to definition at odds with the more standard definition of "occurring at the same coordinate time". Human history, for example, would all be defined as "simultaneous" to an eye blink of a distant alien. And similarly, the history of the alien race would all be "simultaneous" to a blink of your eyes. This is a confusing and unhelpful definition of simultaneous.

This is why we say "x neither precedes nor follows y" instead of saying "x and y are simultaneous".

roosh

Morbert wrote: »

And that response is absolutely meaningless. It is completely and entirely beside the point. Maybe this is why you think I am ignoring your response. The ordering of events is absolutely relative to the observer. More specifically, it is relative to the set of instruments used to make the measurement. Even more specifically, we can say that the measured order of events will differ between measurement apparatuses as a function of the relative velocity between the apparatuses. This is a fact, and you highlighting some arbitrary difference between simultaneity and the quality of film does nothing to counter that fact.


This is also irrelevant. Despite it's irrelevance, I have already told you that, yes, it is not intrinsic to the measurement instruments. It is, however, intrinsic to the relative velocity between those instruments and the objects they are being applied to.



Yes, we only measure physical things. But how we measure things, and how those measurements are expressed (I.e. Length, duration, ordering) involves frames of references.

Although it is a point I would like to explore further it probably is just an "irrelevant digression", with regard to the question in hand. The physical ordering of events certainly appears to be irrelevant, becuase it doesn't seem to affect how an observers brain processes the photons which physically strike the observer's retinae; we can see this from the fact that Henry's brain will process an ordered experience, inspite of the fact that the ordering of events isn't physical and one doesn't chronologically precede the other. The same must also be true for Albert's brain.

Morbert wrote: »

Absolutely not. That is a bare faced assertion that can be dismissed out of hand. It is antithetical to the very principle of relativity.

If the interpretation of the principle of relativity requires us to accept that, when it comes to generating Albert's experiences, Henry's brain is on a par with Albert's, the I would suggest that interpretation of the principle of relativity needs revisiting; because Albert's experiences are generated by Albert's brain, not Henry's.

Morbert wrote: »

The above is an irrelevant objection to my shorthand description of the clocks. While I'm always happy to clarify, I won't entertain irrelevant digressions. By different clocks, I mean different coordinate measures. Further digressions of this kind will be summarily ignored.

As you mentioned, the analogy you were using was to demonstrate how non-physical characteristics can be ascribed to physical events. What it didn't demonstrate was that this is true for the ordering of events; because it was demonstrated how the two were sufficiently different to mean they weren't analogous in that way.

But, it probably is just an "irrelevant digression", because the physical ordering of the photon events, or the physical chronology of those events doesn't appear to affect how an observers brain will process them. Henry's brain will process an ordered experience, despite the abscence of a physical chronology.

Morbert wrote: »

This absolutely contradicts what you are saying. The ordering of events, i.e. the coordinate time labels of events, plays no role in what is happening at a fundamental level. What you are saying is that they do. You are saying the coordinate time labels generated by the measurement apparatus (Albert's Brain) plays a role in what is happening on a fundamental level.

That's not what I'm saying at all; I'm saying that if photons physically strike Albert's retinae while he is standing on the embankment, and they do so in the order of one first, then the other, then his brain will process them to generate an ordered experience. We know this, because Albert has ordered experiences all the time.

The question then is, do the physical photons strikes occur in the order of one first, then the other, while Albert is standing on the embankment?

Morbert wrote: »

No. S' says the physical strikes occur in a different order, but that the measurement apparatus that is Albert's brain, whether it is taken to be a single cpu or a complex web of neurons, will measure the strikes as occurring simultaneously. I'll repeat it again, because you consistently, repeatedly, exasperatingly, keep... ignoring... this... fact: S' "says" that Albert's brain will measure the strikes to be simultaneous.

I'm not saying that S' says any differently.

Morbert wrote: »

S' says that Albert's brain will measure the strikes to be simultaneous.
S' says that any measurement apparatus that is stationary relative to the poles will measure the strikes to be simultaneous.
S' says that retinas and a single cpu, or a single light detector, or a complex brain, or a convoluted apparatus consisting of elephants, fruit bats, and disgruntled postal employees will measure the strikes to be simultaneous if the apparatus is stationary with respect to the pole.

The physical world says that if photons physically strike Albert's retinae while he is standing on an embankment, and they do so in the order of one first, then the other, then his brain will process an ordered experience.

S' says that the physical photon strikes occur in the order of one first then the other; therefore Albert's brain should generate an ordered experience.

Morbert wrote: »

Therefore... when you say "if [the coordinate times of] S' correspond to physical events, then Albert's brain should generate a non-simultaneous experience", you are dead wrong. You are dead wrong because, while S' says the strikes occurred non-simultaneously, it also says any apparatus stationary with respect to the strikes will measure the strikes to be simultaneous.

I'm not suggesting that the mathematical reference frame implies anything different; I'm saying the physical world does.

Morbert wrote: »

The "time ordering" refers to coordinate time, which is not in the the same context of the "chronological precedence" statements made by Wikipedia.

Although it isn't necessarily relevant, could you recommend any other references on that point?

Morbert wrote: »

Also, when they say the ordering of events between three spacelike events might not be arbitrary, they mean that, if you have three events A,B and C, they can appear in the order A,B,C, or C,B,A, or be simultaneous, but some orders like C,A,B, or B,C,A, or B,A,C, are impossible. This is true, but irrelevant to the current conversation.

Indeed, I was only referencing their use of the term "chronology".

Morbert wrote: »

No. The interval is frame-independent. It is a physical relation, and therefore not implying any frame of reference. So all observers will agree.

Is it possible for two events to have the same interval, according to S', yet actually be timelike separated; I'm guessing it should be.

Morbert wrote: »

In a trivial sense, yes. We can define an absolute simultaneity if we define everything outside the light cones of an event as simultaneous with that event. But this leads to definition at odds with the more standard definition of "occurring at the same coordinate time". Human history, for example, would all be defined as "simultaneous" to an eye blink of a distant alien. And similarly, the history of the alien race would all be "simultaneous" to a blink of your eyes. This is a confusing and unhelpful definition of simultaneous.

This is why we say "x neither precedes nor follows y" instead of saying "x and y are simultaneous".

I'll leave the lightcone discussion to the other thread, unless you'd prefer to merge it in here.

Morbert

The core of the issue:

roosh wrote: »

if photons physically strike Albert's retinae while he is standing on the embankment, and they do so in the order of one first, then the other, then his brain will process them to generate an ordered experience.

That statement is frame-dependent. It is true for S. It is not true for S'. According to S', photons that physically strike Albert's retinas, while he is standing on the embankment, in the order of one first, then the other, will be measured as simultaneous by Albert's brain. Neither S nor S' is more correct. Simultaneity, in other words, is relative.

I'll leave the light cone stuff for the other thread.

roosh

Morbert wrote: »

The core of the issue:



That statement is frame-dependent. It is true for S. It is not true for S'. According to S', photons that physically strike Albert's retinas, while he is standing on the embankment, in the order of one first, then the other, will be measured as simultaneous by Albert's brain. Neither S nor S' is more correct. Simultaneity, in other words, is relative.

I'll leave the light cone stuff for the other thread.

The ordering might be frame dependent; that Albert's brain processes photons in the order they physically strike his retinae, isn't.

While S and S' might mathematically agree that the photons reach an idealised processing centre simultaneously, the physical world doesn't.

Put yourself in Albert's shoes; if you are standing on the embankment and two photons physically strike your retine, and do so in the order of one first, then the other, then your brain will process and ordered experiece; simply because that is how your brain operates when generating your experiences.

Morbert

roosh wrote: »

The ordering might be frame dependent; that Albert's brain processes photons in the order they physically strike his retinae, isn't.

While S and S' might mathematically agree that the photons reach an idealised processing centre simultaneously, the physical world doesn't.

That is simply not the case at all. Whether or not Albert's brain processes photons in the order they strike his retinas is absolutely frame dependent. And the physical world most certainly says all observers will agree that the photons reach an idealised processing centre simultaneously. All co-incident events (events that happen at the same place and time) are agreed to be coincident by all observers. That co-incidence is fundamentally physical. If it wasn't, causality itself would be oberver-dependent, which is obviously absurd.

Put yourself in Albert's shoes; if you are standing on the embankment and two photons physically strike your retine, and do so in the order of one first, then the other, then your brain will process and ordered experiece; simply because that is how your brain operates when generating your experiences.

This paragraph is just a reiteration of your previous assertion, and it is wrong. That is not how your brain operates when generating experiences, whether we are talking about an idealised brain or a realistic brain. If I experience simultaneous blindness, then the most I can say is the photon strikes occured simultaneosly according to the reference frame that labels my brain stationary.

Let me ask you this: Say we mix up the experiment a little. Let's say Albert is on the train and Henry is on the embankment. Let's also say the rods are on the train. Henry controls the rods, and fires one laser first, then the other, such that the photons strike one of Albert's retinas first, then the other. Albert, however, experiences the blindness simultaneously. Would you still maintain that Albert's measurements/experiences are more indicative of reality than Henry's

roosh

Morbert wrote: »

That is simply not the case at all. Whether or not Albert's brain processes photons in the order they strike his retinas is absolutely frame dependent. And the physical world most certainly says all observers will agree that the photons reach an idealised processing centre simultaneously. All co-incident events (events that happen at the same place and time) are agreed to be coincident by all observers. That co-incidence is fundamentally physical. If it wasn't, causality itself would be oberver-dependent, which is obviously absurd.

The generation of Albert's experiences doesn't depend on how they are described mathematically; that is, they are not frame dependent; it doesn't even depend on the physical frame of reference that he finds himself in, because, regardless of where he is, his brain will process sensory stimuli in the same manner.

Albert's brain processes physical stimuli in the order in which the stimuli make physical contact with his sensory organs. While the order, in which the stimuli make physical contact with his sensory organs, might be "frame dependent" this physical fact isn't. It's true for all reference frames. The issue lies in what the other reference frames say about how the process is executed by the brain; but what those other reference frames say, mathematically, about how Albert's brain generates Albert's experience is immaterial, because we know how Albert's brain physically generates Alberts experiences from physical, sensory stimuli which makes physical contact with his sensory organs.

Morbert wrote: »

This paragraph is just a reiteration of your previous assertion, and it is wrong. That is not how your brain operates when generating experiences, whether we are talking about an idealised brain or a realistic brain. If I experience simultaneous blindness, then the most I can say is the photon strikes occured simultaneosly according to the reference frame that labels my brain stationary.

So, now you are suggesting that we use physical observations to make deductions about mathematical reference frames. That is getting the cart before the horse. We use the mathematical reference frames to make deductions about the physcal world.

And S' says that the photons make physical contact with one retinae first and then the other; if the photons make physical contact with Albert's sensory organs in that order; that is, if photons make physcial contact with one retina first and then the other, then that is how Albert's brain will process them, in the overall process of generating his experience.

Morbert wrote: »

Let me ask you this: Say we mix up the experiment a little. Let's say Albert is on the train and Henry is on the embankment. Let's also say the rods are on the train. Henry controls the rods, and fires one laser first, then the other, such that the photons strike one of Albert's retinas first, then the other. Albert, however, experiences the blindness simultaneously. Would you still maintain that Albert's measurements/experiences are more indicative of reality than Henry's

If the photons make physical contact with one retina first and then the other, Albert won't have a simultaneous experience.

EDIT: if you are standing in your front garden and a pair of photons make physical contact with your eyes in the order of one first then the other; that is, one photon makes physical contact with one eye first and the other photon makes physical contact with the other eye second; what kind of experience will your brain generate?

Morbert

roosh wrote: »

The generation of Albert's experiences doesn't depend on how they are described mathematically; that is, they are not frame dependent; it doesn't even depend on the physical frame of reference that he finds himself in, because, regardless of where he is, his brain will process sensory stimuli in the same manner.

Albert's brain processes physical stimuli in the order in which the stimuli make physical contact with his sensory organs. While the order, in which the stimuli make physical contact with his sensory organs, might be "frame dependent" this physical fact isn't. It's true for all reference frames. The issue lies in what the other reference frames say about how the process is executed by the brain; but what those other reference frames say, mathematically, about how Albert's brain generates Albert's experience is immaterial, because we know how Albert's brain physically generates Alberts experiences from physical, sensory stimuli which makes physical contact with his sensory organs.

You are deeply frustrating. It is like arguing with a man who insists the sky is green because he has been living in a forest all his life.

How Albert's brain orders physical stimuli is frame dependent. Everything you said in red is false. It is wrong. It is incorrect. It is not true on any physical or metaphysical level.

So, now you are suggesting that we use physical observations to make deductions about mathematical reference frames. That is getting the cart before the horse. We use the mathematical reference frames to make deductions about the physcal world.

And S' says that the photons make physical contact with one retinae first and then the other; if the photons make physical contact with Albert's sensory organs in that order; that is, if photons make physcial contact with one retina first and then the other, then that is how Albert's brain will process them, in the overall process of generating his experience.

No. I have told you over and over and over and over and over and over and over that the statement in blue is a frame dependent statement. It is true according to S. It is not true according to S'. According to S', the retinas are struck non-simultaneously, but due to the hyperbolic structure of spacetime, the same structure responsible for the universal speed of light, the signal travels through one wire in a more dilated manner than the other. This description is absolutely frame dependent. No argument there. But it is no more or less frame dependent than Albert's description of events. We have two descriptions of the interactions between light, retinas, wires, and a cpu. You cannot say one is more physical than the other.

You cannot say one description is more indicative of reality than the other. No you cannot.

If the photons make physical contact with one retina first and then the other, Albert won't have a simultaneous experience.

But he would. Henry could push one button first, then the other, triggering the lasers to fire non-simultaneously, and would strike Albert's retinas non simultaneously. He could do so in such a way that Albert would experience the flashes as simultaneous. Who is wrong in this case?

In case you are tempted to blame the discrepancy on the signalling from the button pushes to the rods, let's embed the rods alongside the track, such that the wires are perpendicular to the track, and parallel to each other.

EDIT: if you are standing in your front garden and a pair of photons make physical contact with your eyes in the order of one first then the other; that is, one photon makes physical contact with one eye first and the other photon makes physical contact with the other eye second; what kind of experience will your brain generate?

The question presupposes a frame, but you do not specify which frame. For example, is this a frame in which I am stationary? Or is this a frame in which I am tumbling very fast through space on a rotating rock? You cannot make a frame-dependent statement without tendering the frame.

roosh

Morbert wrote: »

You are deeply frustrating. It is like arguing with a man who insists the sky is green because he has been living in a forest all his life.

How Albert's brain orders physical stimuli is frame dependent. Everything you said in red is false. It is wrong. It is incorrect. It is not true on any physical or metaphysical level.



No. I have told you over and over and over and over and over and over and over that the statement in blue is a frame dependent statement. It is true according to S. It is not true according to S'. According to S', the retinas are struck non-simultaneously, but due to the hyperbolic structure of spacetime, the same structure responsible for the universal speed of light, the signal travels through one wire in a more dilated manner than the other. This description is absolutely frame dependent. No argument there. But it is no more or less frame dependent than Albert's description of events. We have two descriptions of the interactions between light, retinas, wires, and a cpu. You cannot say one is more physical than the other.

You cannot say one description is more indicative of reality than the other. No you cannot.




But he would. Henry could push one button first, then the other, triggering the lasers to fire non-simultaneously, and would strike Albert's retinas non simultaneously. He could do so in such a way that Albert would experience the flashes as simultaneous. Who is wrong in this case?

In case you are tempted to blame the discrepancy on the signalling from the button pushes to the rods, let's embed the rods alongside the track, such that the wires are perpendicular to the track, and parallel to each other.

Relativity says that if Albert, or you, are standing on the embankment with metre stick and clock in hand, as far as you are concerned, the metre stick is not contracted and time is not dilated; this goes for your brain too. So, when a photon makes physical contact with your eyes, while you are standing on an embankment, that is how your body will process it, as though length is not contracted and time is not dilated. This is under parabolic geometry also.

If photons make physical contact with your eyes in the order of one first, then the other, then your body will process them in that order and your brain will generate an ordered experience.

Morbert wrote: »

The question presupposes a frame, but you do not specify which frame. For example, is this a frame in which I am stationary? Or is this a frame in which I am tumbling very fast through space on a rotating rock? You cannot make a frame-dependent statement without tendering the frame.

You are standing on an embankment, at rest relative to it, where there is relative motion between you and a train, and whatever other objects you like to insert. The statements you make above are statements about the absolute nature of motion of the objects in question, not absolute statements about relative motion. They are also, apparently, just different ways of artificially labeling the same physical scenario; the artificial labels should have no bearing on the physical behaviour at a fundamental level; just as the the process of pouring tea into a cup shouldn't be affected differently by saying "the tea is poured into the cup" and making the equivalent statement in a different language; where the different languages represent different ways of artificially labeling the same physical process.

Morbert

roosh wrote: »

Relativity says that if Albert, or you, are standing on the embankment with metre stick and clock in hand, as far as you are concerned, the metre stick is not contracted and time is not dilated; this goes for your brain too. So, when a photon makes physical contact with your eyes, while you are standing on an embankment, that is how your body will process it, as though length is not contracted and time is not dilated. This is under parabolic geometry also.

If photons make physical contact with your eyes in the order of one first, then the other, then your body will process them in that order and your brain will generate an ordered experience.

This is correct as far as Albert is concerned. As far as someone else is concerned, it is not correct. And since relativity says no perspective is preferred, you cannot say Albert's perspective is more correct.

Again, according to Albert, the photons that strike Albert simultaneously will be perceived simultaneously. But according to Henry, the photons strike Albert in the order of one fist then the other and will be perceived by Albert simultaneously.

You are standing on an embankment, at rest relative to it, where there is relative motion between you and a train, and whatever other objects you like to insert. The statements you make above are statements about the absolute nature of motion of the objects in question, not absolute statements about relative motion. They are also, apparently, just different ways of artificially labeling the same physical scenario; the artificial labels should have no bearing on the physical behaviour at a fundamental level; just as the the process of pouring tea into a cup shouldn't be affected differently by saying "the tea is poured into the cup" and making the equivalent statement in a different language; where the different languages represent different ways of artificially labeling the same physical process.

You have made serveral mistakes above. I will ignore the irrelevant mistakes and address the relevant ones: All frames agree that you are at rest relative to the embankment. All frames agree that there is relative motion between you and the train. Therefore you have not specified the frame you are referring to. And since you have not specified the frame you are referring to, I cannot interpret your premise in a non-ambiguous manner. Is this a frame, for example, where I and the embankment are at rest? Is this a frame where I and the embankment are orbiting the sun at a phenomenal rate? Is this a frame where I am orbiting the galaxy at an even more phenomenal rate? Is this a frame where the galaxy I am in is itself flying through our local cluster?

roosh

Morbert wrote: »

This is correct as far as Albert is concerned. As far as someone else is concerned, it is not correct. And since relativity says no perspective is preferred, you cannot say Albert's perspective is more correct.

Again, according to Albert, the photons that strike Albert simultaneously will be perceived simultaneously. But according to Henry, the photons strike Albert in the order of one fist then the other and will be perceived by Albert simultaneously.

So, as far as Albert is concerned, photons which make physical contact with his retinae will be processed in the order they make physical contact; such that, if photons make physical contact with his retinae in the order of one first, then the other, while he is standing on the embankment, his brain will generate an ordered experience.

According to relativity, photons make physical contact with Albert's retinae, while he is standing on the embankment, in the order of one first, then the other as well as not in that order; with both scenarios being equally true; therefore, Albert's brain should generate discordant experiences. Anything else is superfluous to the point.


It might be tempting to say that the photons don't strike Albert's retinae in the order of one first, then the other, as far as Albert is concerned, but anything which makes physical contact with Albert concerns him, while the physicality of the ordering doesn't matter, given that Henry's brain will generate an ordered experience despite the fact that the ordering of the events isn't physical.

Morbert wrote: »

You have made serveral mistakes above. I will ignore the irrelevant mistakes and address the relevant ones: All frames agree that you are at rest relative to the embankment. All frames agree that there is relative motion between you and the train. Therefore you have not specified the frame you are referring to. And since you have not specified the frame you are referring to, I cannot interpret your premise in a non-ambiguous manner. Is this a frame, for example, where I and the embankment are at rest? Is this a frame where I and the embankment are orbiting the sun at a phenomenal rate? Is this a frame where I am orbiting the galaxy at an even more phenomenal rate? Is this a frame where the galaxy I am in is itself flying through our local cluster?

Again, there are a number of issues with the statements above, all of which are relevant.

The questions you raise above, are are just different ways of artificially labeling the same physical scenario, according to yourself; how a physical scenario is artificially labeled should have no bearing at the fundamental, physical level; otherwise you are making a statement about the absolute motion of you and the embankment.

In the physical scenario, and in every reference frame, you are moving relative to the sun and at rest relative to the embankment. Throw in any other physical object you please and it won't change that.


By the way, when you say a frame where you and the embankment are at rest, relative to what other physical object do you mean?

Morbert

roosh wrote: »

So, as far as Albert is concerned, photons which make physical contact with his retinae will be processed in the order they make physical contact; such that, if photons make physical contact with his retinae in the order of one first, then the other, while he is standing on the embankment, his brain will generate an ordered experience.

According to relativity, photons make physical contact with Albert's retinae, while he is standing on the embankment, in the order of one first, then the other as well as not in that order; with both scenarios being equally true; therefore, Albert's brain should generate discordant experiences. Anything else is superfluous to the point.


It might be tempting to say that the photons don't strike Albert's retinae in the order of one first, then the other, as far as Albert is concerned, but anything which makes physical contact with Albert concerns him, while the physicality of the ordering doesn't matter, given that Henry's brain will generate an ordered experience despite the fact that the ordering of the events isn't physical.

And as far as Henry is concerned, if photons strike Albert's retinas in the order of one first and then the other, Albert will experience the strikes as simultaneous. And no reference is privileged, so Henry is no more or less correct than Albert.

Again, there are a number of issues with the statements above, all of which are relevant.

The questions you raise above, are are just different ways of artificially labeling the same physical scenario, according to yourself; how a physical scenario is artificially labeled should have no bearing at the fundamental, physical level; otherwise you are making a statement about the absolute motion of you and the embankment.

In the physical scenario, and in every reference frame, you are moving relative to the sun and at rest relative to the embankment. Throw in any other physical object you please and it won't change that.

Again, it is clear that you have absolutely no idea what you are talking about. You are tendering a physically ambiguous scenario. It is a physically ambiguous scenario because you yourself are tendering an artificial label, a coordinate statement ("one first then the other"), without specifying the coordinate frame you are using. So unless you specify the frame, your scenario is incoherent. It is not a matter of fundamental physics. It is a matter of you not making a meaningful statement, because you are making a coordinate statement without referencing a coordinate system.

By the way, when you say a frame where you and the embankment are at rest, relative to what other physical object do you mean?

Relative to a hypothetical set of perfect clocks and rulers which would provide a specific reference.

roosh

Morbert wrote: »

And as far as Henry is concerned, if photons strike Albert's retinas in the order of one first and then the other, Albert will experience the strikes as simultaneous. And no reference is privileged, so Henry is no more or less correct than Albert.




Again, it is clear that you have absolutely no idea what you are talking about. You are tendering a physically ambiguous scenario. It is a physically ambiguous scenario because you yourself are tendering an artificial label, a coordinate statement ("one first then the other"), without specifying the coordinate frame you are using. So unless you specify the frame, your scenario is incoherent. It is not a matter of fundamental physics. It is a matter of you not making a meaningful statement, because you are making a coordinate statement without referencing a coordinate system.



Relative to a hypothetical set of perfect clocks and rulers which would provide a specific reference.

It can essentially be boiled down to this:

As far as you are concerned, your body will process all photons which make physical contact with your retinae, while you are standing in your front garden; and it will process all photons which make physical contact, in the same manner; that is, in the order they make physical contact, while you are standing in your front garden. Your brain will generate an experience which corresponds to the order in which the photons make physical contact with your retinae; where the physicality of the ordering is irrelevant, and with it, which frame specifies which order - the important pieces of information are whether or not they make physical contact and the fact that the order, in which they make physical contact, is different.

Supposedly, photons make physical contact with your retinae in two different orders, while you are standing in your front garden, therefore, your brain should generate two different, discordant, experiences; as far as you are concerned.

Morbert

roosh wrote: »

It can essentially be boiled down to this:

As far as you are concerned, your body will process all photons which make physical contact with your retinae, while you are standing in your front garden; and it will process all photons which make physical contact, in the same manner; that is, in the order they make physical contact, while you are standing in your front garden. Your brain will generate an experience which corresponds to the order in which the photons make physical contact with your retinae; where the physicality of the ordering is irrelevant, and with it, which frame specifies which order - the important pieces of information are whether or not they make physical contact and the fact that the order, in which they make physical contact, is different.

Supposedly, photons make physical contact with your retinae in two different orders, while you are standing in your front garden, therefore, your brain should generate two different, discordant, experiences; as far as you are concerned.

You are treating frames of references inconsistently, as you refuse, somewhat suspiciously, to apply the Lorentz transformations to relate measures used by myself and Henry. As far as I am concerned, the photons strike my retinas simultaneously and I experience blindness in both eyes simultaneously. As far as Henry is concerned, the photons strike my retinas in the order of one first, then the other, and I experience blindness simultaneously. You cannot use Henry's coordinates to label the events, and then carry those labels to my coordinate system without the relevant Lorentz transformations. That is why you are predicting discordant experiences.

[edit]- Note, your phrase "as far as X is concerned" is only valid if it is interpreted as "according to the reference frame which measures X as at rest". If you mean something else, then your premise can be dismissed out of hand as inconsistent.

roosh

Morbert wrote: »

You are treating frames of references inconsistently, as you refuse, somewhat suspiciously, to apply the Lorentz transformations to relate measures used by myself and Henry. As far as I am concerned, the photons strike my retinas simultaneously and I experience blindness in both eyes simultaneously. As far as Henry is concerned, the photons strike my retinas in the order of one first, then the other, and I experience blindness simultaneously. You cannot use Henry's coordinates to label the events, and then carry those labels to my coordinate system without the relevant Lorentz transformations. That is why you are predicting discordant experiences.

[edit]- Note, your phrase "as far as X is concerned" is only valid if it is interpreted as "according to the reference frame which measures X as at rest". If you mean something else, then your premise can be dismissed out of hand as inconsistent.

That can be dismissed out of hand because it is inconsistent, as it relies on a statement about the absolute nature of motion of X. You should be saying "according to the reference frame which measures X as at rest relative to the hypothetical measuring instruments", but, of course, every reference frame measures X as being at rest relative to those.

But maybe we've been looking at this the wrong way, by focusing solely on light; if we amend the original thought experiment such that there is a device on each pole which emits a sound when the lightning makes physical contact with it.

If we use dlouth's (was it dlouth's?) device with the light, where the light only switches on if it struck simultaneously, and amend it so that the light only switches on if the sound waves strike it simultaneously.

Here, the differing order of the events should give rise to a paradox, shouldn't it, where the light switches on according to one reference frame but not the other.


We make the proviso, of course, that Albert (or the light device) and the rods are at rest relative to the medium through which the sound waves travel; we can put him in a dome or something like that, if necessary.

citrus burst

This thread has become a bit farcical. Roosh I don't know where you get your assumed authority in this field against the back drop of over 400 years of physics. Time and time again you refuse to listen to what people have said to you. Ignored basic comments out of hand, responded with at best vague or wordy answers and refused outright to accept the ideas of what people have been rather patiently trying to explain to you.

Special relativity is in no way fully correct. It doesn't take into account many things, such as forces. However, it does make extremely accurate predictions and is a good approximation for most things. It is totally self consistent, which cannot be said for what you are trying to argue. It correctly predicts electrodynamics, which pretty much by itself should be enough proof for anyone. Electrodynamics being the corner stone of modern physics, for relativity to be consistent with it, without any alterations or as you call them "mathematical tricks" is a huge success for the theory.

roosh wrote: »

That can be dismissed out of hand because it is inconsistent, as it relies on a statement about the absolute nature of motion of X. You should be saying "according to the reference frame which measures X as at rest relative to the hypothetical measuring instruments", but, of course, every reference frame measures X as being at rest relative to those.

What is inconsistent with what Morbert said? How can you just dismiss it? You've just given a hand waving argument that doesn't really answer or say anything?

roosh wrote: »

absolute nature of motion of X

What is absolute about motion? No object is in any way "absolutely" moving. Prove to me this notion of absoluteness that motion apparently has.

roosh wrote: »

You should be saying "according to the reference frame which measures X as at rest relative to the hypothetical measuring instruments",

Again this is just a way you have developed to get out of something, that at this stage even you know, albeit are unwilling to admit, answering a question or actually having to engage and think about.

When we say something is at rest, we mean its not moving relative to something. As I sit here writing I am at rest relative to the earth, my house etc. I am not at rest relative to an airplane flying over head, neither is my house or the earth. We call these objects that are at rest relative to each other reference frames. Basically anything that is moving at a constant velocity can be considered a reference frame and anything that is moving a the same velocity as reference frame can be considered at rest, relative to it. That is the people on the airplane are at rest with airplane (assuming there are not moving up and down it). Every reference frame has an associated coordinate system that is different then every other reference frame. These coordinate systems can extend for most intents and purposes to infinity. So the airplane has a coordinate system, that says the passengers don't move relative to it, but the entire rest of the earth does.

This is an important point, to sum it up means that pretty much any object can be considered a rest frame. But as you pointed out there are inconsistencies when we deal with two or more reference frames, or objects moving relative to each other. If someone on the airplane dropped something, according to everyone on the plane, it would fall down in a straight line, relative to the plane. Someone at rest relative to the earth might say that it fell in some sort of parabolic curve. These inconsistencies are dealt with by applying some sort of transformation. This is what all relativity tries to achieve. Classical mechanics sorted it out years ago, for relatively slow moving and moderately sized objects.

Relativity is pointless if you don't consider two or more objects. If the airplane was all that existed in the universe, you wouldn't need to do any of this. You have been talking about how an outside observers measurements influence another measurement and should in fact send the whole physical world into chaos. But every time you say it, you say we don't care what the other observer measures. In this case you don't need to invoke relativity, you've basically answered your own question.

roosh wrote: »

But maybe we've been looking at this the wrong way, by focusing solely on light; if we amend the original thought experiment such that there is a device on each pole which emits a sound when the lightning makes physical contact with it.

The reason we focus on light is because special relativity is essentially a theory on light. By doing this experiment we are taking a step back, to the world of classical mechanics.

roosh wrote: »

If we use dlouth's (was it dlouth's?) device with the light, where the light only switches on if it struck simultaneously, and amend it so that the light only switches on if the sound waves strike it simultaneously.

roosh wrote: »

Here, the differing order of the events should give rise to a paradox, shouldn't it, where the light switches on according to one reference frame but not the other.

Nope, let me explain why. You have made an assumption about the light and its device, while only considering one reference frame, the one where you are at rest. In it you have set up an operation system, the light only turns on when it receives two signals at the same time according to someone at rest to the set up.

Lets jump the gun a bit. Two observers, one at rest relative to the set up and one moving relative to it at 0.5c no nothing about how the light operates. Both see the light turn on and try to figure out the mechanics of the light. Both agree that the light turns on when it receives two signals. However the guy at rest says it turns on when the two signals arrive at the same time, but the guy moving relative says it turns on when the two signals arrive at some time interval. Both start testing around and confirm that the light only turns on when the time interval is the same as when if first turned on, t=0 for the guy at rest and t=t for the guy moving relative. So as we would expect causality is not affected.

The problem arose with your initial assumption about the operation of the light.

Morbert

roosh wrote: »

That can be dismissed out of hand because it is inconsistent, as it relies on a statement about the absolute nature of motion of X. You should be saying "according to the reference frame which measures X as at rest relative to the hypothetical measuring instruments", but, of course, every reference frame measures X as being at rest relative to those.

The above is completely unrelated to anything I said.

But maybe we've been looking at this the wrong way, by focusing solely on light; if we amend the original thought experiment such that there is a device on each pole which emits a sound when the lightning makes physical contact with it.

If we use dlouth's (was it dlouth's?) device with the light, where the light only switches on if it struck simultaneously, and amend it so that the light only switches on if the sound waves strike it simultaneously.

Here, the differing order of the events should give rise to a paradox, shouldn't it, where the light switches on according to one reference frame but not the other.


We make the proviso, of course, that Albert (or the light device) and the rods are at rest relative to the medium through which the sound waves travel; we can put him in a dome or something like that, if necessary.

So does this mean you accept that no contradiction is evident in your previous thought experiment?

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.

roosh

citrus burst wrote: »

What is inconsistent with what Morbert said? How can you just dismiss it? You've just given a hand waving argument that doesn't really answer or say anything? What is absolute about motion? No object is in any way "absolutely" moving. Prove to me this notion of absoluteness that motion apparently has.

This goes back to a discussion myself and Morbert were having in a different thread, about "statements absolute motion" and "absolute statements of relative motion". Morbert was saying that the former is not something we can make, we can only make statements of the latter variety; however, his statement was a statement about the absolute motion of X because it didn't specify relative to what X was at rest.

citrus burst wrote: »

Again this is just a way you have developed to get out of something, that at this stage even you know, albeit are unwilling to admit, answering a question or actually having to engage and think about.

If I was pursuing the same line of reasoning I would address it, but it appears to be fruitless; because the line of reasoning has changed, there isn't too much need to pursue it much further.

citrus burst wrote: »

When we say something is at rest, we mean its not moving relative to something. As I sit here writing I am at rest relative to the earth, my house etc. I am not at rest relative to an airplane flying over head, neither is my house or the earth. We call these objects that are at rest relative to each other reference frames. Basically anything that is moving at a constant velocity can be considered a reference frame and anything that is moving a the same velocity as reference frame can be considered at rest, relative to it. That is the people on the airplane are at rest with airplane (assuming there are not moving up and down it). Every reference frame has an associated coordinate system that is different then every other reference frame. These coordinate systems can extend for most intents and purposes to infinity. So the airplane has a coordinate system, that says the passengers don't move relative to it, but the entire rest of the earth does.

This is an important point, to sum it up means that pretty much any object can be considered a rest frame. But as you pointed out there are inconsistencies when we deal with two or more reference frames, or objects moving relative to each other. If someone on the airplane dropped something, according to everyone on the plane, it would fall down in a straight line, relative to the plane. Someone at rest relative to the earth might say that it fell in some sort of parabolic curve. These inconsistencies are dealt with by applying some sort of transformation. This is what all relativity tries to achieve. Classical mechanics sorted it out years ago, for relatively slow moving and moderately sized objects.

Relativity is pointless if you don't consider two or more objects. If the airplane was all that existed in the universe, you wouldn't need to do any of this. You have been talking about how an outside observers measurements influence another measurement and should in fact send the whole physical world into chaos. But every time you say it, you say we don't care what the other observer measures. In this case you don't need to invoke relativity, you've basically answered your own question.

This isn't in dispute; Morebert specified the interpretation of "according to X" which was, supposedly, required; but this was inconsistent with points made in our previous discussions.

citrus burst wrote: »

The reason we focus on light is because special relativity is essentially a theory on light. By doing this experiment we are taking a step back, to the world of classical mechanics.

So relativity is true for light but not for sound?

citrus burst wrote: »

Nope, let me explain why. You have made an assumption about the light and its device, while only considering one reference frame, the one where you are at rest. In it you have set up an operation system, the light only turns on when it receives two signals at the same time according to someone at rest to the set up.

Lets jump the gun a bit. Two observers, one at rest relative to the set up and one moving relative to it at 0.5c no nothing about how the light operates. Both see the light turn on and try to figure out the mechanics of the light. Both agree that the light turns on when it receives two signals. However the guy at rest says it turns on when the two signals arrive at the same time, but the guy moving relative says it turns on when the two signals arrive at some time interval. Both start testing around and confirm that the light only turns on when the time interval is the same as when if first turned on, t=0 for the guy at rest and t=t for the guy moving relative. So as we would expect causality is not affected.

The problem arose with your initial assumption about the operation of the light.

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.