Question on Lorentz transforms and relativity of simultaneity

roosh

Morbert wrote: »

I can't make sense of this. Nobody is saying Albert's brain processes Albert's experiences by viewing itself from a relatively moving train.
That you would think anyone is saying this seriously suggests you do not understand the responses you are getting.

Applying the LTs to Albert's brain activity gives us the perspective of the observer in the relatively moving train. That isn't how Albert's brain processes Albert's experience, from its perspective on the embankment.

Morbert wrote: »

For one thing, it doesn't even make sense to say the brain processes experiences. Instead, the brain generates experience, based on stimulus.

Now you're just playing semantics.

Albert's brain processes stimuli to generate Albert's experiences; the generation of Albert's experiences is itself a process carried out by the brain.

Morbert wrote: »

You can repeat this falsehood as often as you want. I will continue to correct you.

And I will continue to point out the rudimentary facts about the physical world, which you are consistently trying to ignore.

Morbert wrote: »

1) The simultaneity of events is a frame-dependent observation, and not a physical or absolute characteristics of events.

Photons physically strike observers' retinae, in the physical world; an observer's brain processes the stimuli from the photons to generate what they see as a "flash of light". Observers experience ordered experiences of such things as flashes of light; this means that they see one flash first and another flash second. The reason they see one flash first and another flash second is because the photons from one flash physically strike their retinae first, while the photons from the second flash, physically strike their retinae second.

Morbert wrote: »

2) There are no contradictions or paradoxes, as explicitly shown in my diagrams, as all observers agree on what events are co-incident, even if they don't agree on ordering of events separated by a spacelike interval.

The reference frame S' "says" that the photons physically strike Albert's retinae in the order of one first, then the other, while Albert is physically standing on the embankment.

If the photons physically strike Albert's retinae in the given order, while he is physically standing on the embankment, then his brain will generate an ordered experience.

If S' doesn't say that the photons don't physically strike Albert's retinae in that order, then S' doesn't correspond to the physical world.

Morbert wrote: »

Now.... Do you know what I mean by 1) and 2)

Do you know what I mean by my replies?

Morbert

roosh wrote: »

They disagree on the order in which the photons physically strike Albert's retinae, while he is physically standing on the embankment.

This, together with how Albert's brain processes Albert's experiences; or more pointedly, how his brain processes photons which physically strike his retinae, to produce his experiences, from its location on the embankment, at rest relative to it, the paradox arises.

I will ask you again. Do understanding my posts? This is not a rhetorical question. I genuinely feel that you do not understand my posts. For example, when I say the ordering of events separated by a space-like interval is unphysical, just as time dilation and length contraction are unphysical, do you know what I mean by space-like? When I say the causal structure is invariant under transformation, which means no paradox exists, do you understand?

Morbert

And I will continue to point out the rudimentary facts about the physical world, which you are consistently trying to ignore.

Roosh, I am not going to let you get away with this. Your posts actually have the potential to be quite damaging to anyone reading this who is unfamiliar with relativity. What you say about what is and isn't physical is categorically untrue, and categorically contrary to relativity.

http://en.wikipedia.org/wiki/Relativity_of_simultaneity
"In physics, the relativity of simultaneity is the concept that simultaneity–whether two events occur at the same time–is not absolute, but depends on the observer's reference frame."

http://en.wikipedia.org/wiki/General_covariance
"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."

These are the facts. These are what you ignore.

The physical relation between events is characterised by a structure that is not frame-dependent.

Simultaneity is frame-dependent. Therefore, simultaneity is not part of the physical relation between events.

The causality of events is frame-independent, and is therefore physical.

Therefore, we can conclude two important facts:

1) What S or S' says about the simultaneity of brain activity is not physical. Neither S nor S' is more correct when it comes to the simultaneity of brain activity.

2) What S or S' say about the causal structure of brain activity is physical. Both agree exactly with the causal structure of brain activity. I.e. They agree with what events are causally connected to other events. And they agree with what experiences the stimulus in question will produce.

Therefore, we can conclude one even more important fact:

There is no paradox.

The physics, as mentioned in the above link, is invariant across all observers. What physically happens is agreed upon by all observers. If they disagree over some quality (I.e. Length, time dilation, or the simultaneity of retina strikes), then that quality is unphysical.

roosh

Morbert wrote: »

I will ask you again. Do understanding my posts? This is not a rhetorical question. I genuinely feel that you do not understand my posts. For example, when I say the ordering of events separated by a space-like interval is unphysical, just as time dilation and length contraction are unphysical, do you know what I mean by space-like? When I say the causal structure is invariant under transformation, which means no paradox exists, do you understand?

Likewise, I would like to know if you understand what I mean.

When you say space-like, I take it to mean two events which are spatially separated, where the events don't have a causal influence on each other.

When you say the causal structure is invariant under transfromation I take it to mean that the transformation of the mathematical co-ordinates don't lead to a violation of causlity.

Morbert

roosh wrote: »

Likewise, I would like to know if you understand what I mean.

When you say space-like, I take it to mean two events which are spatially separated, where the events don't have a causal influence on each other.

When you say the causal structure is invariant under transfromation I take it to mean that the transformation of the mathematical co-ordinates don't lead to a violation of causlity.

Close. It means all observers will agree with the causal structure of events. This means that, even if two observers disagree over frame-dependent qualities like simultaneity, they will not disagree over what physically happens as a result of events.

Morbert

I might have identified the problem. Another question: Do you understand what I mean when I say all observers will agree with what events are co-incidental with other events (I.e. If two events occur at the same place and at the same time, all observers will agree that they do so)?

So, for example, using the toy model dlouth introduced: Do you accept that, regardless of the simultaneity of the retina strikes, both S and S' agree that the signals from the retinas strike the central processing unit at the same time. (I.e. One does does not reach the central processing unit before the other)?

roosh

Morbert wrote: »

Roosh, I am not going to let you get away with this. Your posts actually have the potential to be quite damaging to anyone reading this who is unfamiliar with relativity. What you say about what is and isn't physical is categorically untrue, and categorically contrary to relativity.

http://en.wikipedia.org/wiki/Relativity_of_simultaneity
"In physics, the relativity of simultaneity is the concept that simultaneity–whether two events occur at the same time–is not absolute, but depends on the observer's reference frame."

http://en.wikipedia.org/wiki/General_covariance
"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."

What I'm saying about what is an isn't physical is simply a matter of simple deduction; whether or not it is categorically contrary to relativity is immaterial, not least because relativity is, apparently, being questioned. Thus far your argument has simply been "relativity says that isn't true"; but given that relativity is being questioned, that isn't sufficient.

Again, I will state some basic facts about the physical world, if you care to challenge those facts then we might get somewhere, but if you continue to reply with "relativity says it isn't true", then the points will remain, because the points, apparently, are a challenge of "what relativity says".

Basic facts
- photons physically strike Albert's retinae in the physical world

- Albert's brain processes photons which physically strike his retinae, to generate his experience of flashes of light.

- Albert, in the past, has experiences two flashes of light in the sequence of one flash first, the other flash second; or in the order of one first, then the other.

- The reason Albert saw the flahses of light in the first place, was because the photons physically struck his retinae.


What we want to know is why he saw the flashes in the order of one first then the other?

Morbert wrote: »

These are the facts. These are what you ignore.

I could say ditto, but I've posed a question which you might be able to answer.

Morbert wrote: »

The physical relation between events is characterised by a structure that is not frame-dependent.

Simultaneity is frame-dependent. Therefore, simultaneity is not part of the physical relation between events.

The causality of events is frame-independent, and is therefore physical.

The question above speaks directly to these points, I think.

Morbert wrote: »

Therefore, we can conclude two important facts:

1) What S or S' says about the simultaneity of brain activity is not physical. Neither S nor S' is more correct when it comes to the simultaneity of brain activity.

What we can say is that human brains operate in the physical world; they don't operate according to mathematical descriptions of them; when Albert's brain produces Albert's experiences, it does so from it's own perspective and so doesn't apply the LTs to itself.

Morbert wrote: »

2) What S or S' say about the causal structure of brain activity is physical. Both agree exactly with the causal structure of brain activity. I.e. They agree with what events are causally connected to other events. And they agree with what experiences the stimulus in question will produce.

In the physical world, Albert's brain processes all photons which physically strike his retinae in the order they physically strike; with it taking the same time for the signal to reach the processing centre from each retina.

Morbert wrote: »

Therefore, we can conclude one even more important fact:

There is no paradox.

The physics, as mentioned in the above link, is invariant across all observers. What physically happens is agreed upon by all observers. If they disagree over some quality (I.e. Length, time dilation, or the simultaneity of retina strikes), then that quality is unphysical.

Relativity says there is no paradox, but the physical world would seem to disagree.

roosh

Morbert wrote: »

Close. It means all observers will agree with the causal structure of events.

Same difference.

Morbert wrote: »

This means that, even if two observers disagree over frame-dependent qualities like simultaneity, they will not disagree over what physically happens as a result of events.

Indeed, this is what relativity says.

roosh

Morbert wrote: »

I might have identified the problem. Another question: Do you understand what I mean when I say all observers will agree with what events are co-incidental with other events (I.e. If two events occur at the same place and at the same time, all observers will agree that they do so)?

So, for example, using the toy model dlouth introduced: Do you accept that, regardless of the simultaneity of the retina strikes, both S and S' agree that the signals from the retinas strike the central processing unit at the same time. (I.e. One does does not reach the central processing unit before the other)?

This is just the same point again. I do agree that mathematical representations that are S and S', say that they will reach the processing centre at the same time; but Albert's brain which operates in the physical world doesn't.

The issue in the above lies in the philosophical assumptions that relativity tacitly makes about time and how clocks measure it. The relatively moving observer will agree that the timestamp on the two imaginary retinae clocks, in Albert's eyes, will record the same time for the striking events; however, he will still say that they struck the retinae in the order of one first, then the other. This allows us to demonstrate the difference between the simultaneity as determined by a clock and physical order in which photons strike an observers retinae.

If they physically strike Albert's retinae in the order of one first, then the other, then this is how Albert's brain will process them to produce Albert's experience.

Morbert

roosh wrote: »

What we can say is that human brains operate in the physical world; they don't operate according to mathematical descriptions of them; when Albert's brain produces Albert's experiences, it does so from it's own perspective and so doesn't apply the LTs to itself.

In the physical world, Albert's brain processes all photons which physically strike his retinae in the order they physically strike; with it taking the same time for the signal to reach the processing centre from each retina.

You are contradicting yourself here. First, you say humans brains do not operate according to mathematical descriptions of them. However, the simultaneity of events is a mathematical, frame-dependent, description, yet you assume it is physical.

This is just the same point again. I do agree that mathematical representations that are S and S', say that they will reach the processing centre at the same time; but Albert's brain which operates in the physical world doesn't.

The issue in the above lies in the philosophical assumptions that relativity tacitly makes about time and how clocks measure it. The relatively moving observer will agree that the timestamp on the two imaginary retinae clocks, in Albert's eyes, will record the same time for the striking events; however, he will still say that they struck the retinae in the order of one first, then the other. This allows us to demonstrate the difference between the simultaneity as determined by a clock and physical order in which photons strike an observers retinae.

If they physically strike Albert's retinae in the order of one first, then the other, then this is how Albert's brain will process them to produce Albert's experience.

Before I go any further with this, do you, at the very least, accept the fact that relativity is self-consistent. If you start with the postulates of relativity, and carefully apply them, no paradox arises? The above implies you do.

Morbert

Here is what confuses me: In post #31, you are clearly attempting to identify an inconsistency in the theory of relativity.

Now, you seem to have retreated to your old position of "relativity makes tacit assumptions". Does this mean you now understand how relativity is consistent? Do you accept that there is no inconsistency in the theory?

roosh

Morbert wrote: »

You are contradicting yourself here. First, you say humans brains do not operate according to mathematical descriptions of them. However, the simultaneity of events is a mathematical, frame-dependent, description, yet you assume it is physical.

Brains don't operate according to mathematical descriptions of them; the order in which photons physically strike an observers retinae is a matter of physicality; that is, photons can physically strike an observers retinae in sequential order, or together, "tied for first place".

I don't assume that the mathematical, frame-dependent, description, of simultaneity is phyiscal, I ask if it corresponds to the physical world; if it does, then it implies that the photons physically strike Albert's retinae in the order of one first, then the other; if they do physically strike in this order, then his brain will process them in that order.

Morbert wrote: »

Before I go any further with this, do you, at the very least, accept the fact that relativity is self-consistent. If you start with the postulates of relativity, and carefully apply them, no paradox arises? The above implies you do.

That depends on whether or no relativity claims to represent events which occur in the physical world; mathematically, I would say there are no paradoxes, phyiscally, I would say there is.

roosh

Morbert wrote: »

Here is what confuses me: In post #31, you are clearly attempting to identify an inconsistency in the theory of relativity.

Now, you seem to have retreated to your old position of "relativity makes tacit assumptions". Does this mean you now understand how relativity is consistent? Do you accept that there is no inconsistency in the theory?

As mentioned in my last, post which, in fairness I was writing whiel you were typing this; it depends on what the theory of relativity says, with regard to how it corresponds to the physical world. Mathematically I would say it is self-consistent, but when we apply it to the physical world, then it seems that a paradox arises.

roosh

Right, I'm going to hit the hay; it's 2am here, so it's getting (or has already gotten) late.

No doubt we will continue this discussion; I mightn't get the chance to reply til sunday or monday, but I look forward to it, eitherway.

Take care.

Morbert

roosh wrote: »

Brains don't operate according to mathematical descriptions of them; the order in which photons physically strike an observers retinae is a matter of physicality;

Here you are assuming a mathematical, frame-dependent description is physical.

I don't assume that the mathematical, frame-dependent, description, of simultaneity is phyiscal, I ask if it corresponds to the physical world; if it does, then it implies that the photons physically strike Albert's retinae in the order of one first, then the other; if they do physically strike in this order, then his brain will process them in that order.

The answer, is no, it does not. By this, I mean if a reference frame, for example, says two events are simultaneous, that does not correspond to reality. Another frame, which says they are not simultaneous, is no more or less correct. Instead, it is an arbitrary description. Similar to the way a frame might describe the set-up as stationary, or moving at some velocity.

That depends on whether or no relativity claims to represent events which occur in the physical world; mathematically, I would say there are no paradoxes, phyiscally, I would say there is.

And we were so close.

ceejay

At this stage I'm prepared to accept the possibility that roosh is actually just trolling us all

However, just in case you're not -

To state my understanding of your assertion of the paradox, it's the following:

Based on these key assumptions:
- Relativity says that different reference frames result in different descriptions of when the photons hit each retina
- these different descriptions are equally valid descriptions of the order of the real physical events of photons hitting the retinas
- The order of the events at the retinas equals Albert's experience of the order of the events for all descriptions of the sequence of events

This produces the following deduction:
- That the difference descriptions of the order of the events create multiple conflicting experiences in Albert's brain of the same two events

However, Albert clearly doesn't have that kind of experience, he only has one memory of the experience. Hence a paradox arises.

I believe you would agree that the paradox arises because the deduction is false, i.e. people don't have multiple conflicting experiences of the same events, and you are searching for the reason why the deduction is false.

For the deduction to be false one or more of the assumptions must be false:

- The theory of special relativity is incorrect
- The descriptions are not equally valid descriptions of the order of real physical events
- Albert's experience of the order of the events does not equal the order of the events at the retinas for all descriptions of the sequence of the events

Your posts have been questioning the validity of the second assumption mainly, and also now the first assumption. You consistently assert the third assumption as being true without questioning the validity of that assumption.

If we take the first two assumptions to be true and apply the theory of special relativity rigorously, we find that we have to adjust our common sense view of how Albert's experience of the sequence of events is connected to the sequence of events at his retinas for all descriptions of the sequence of events, and we find that the third assumption is not valid. The way Albert's experience of the sequence events is connected to the sequence of events at the retinas is dependent on which description of the events we are considering.

Based on revising the third assumption we can find what happens to the original deduction:
- In all of the descriptions of the real physical events Albert's experience is that the flashes of light were simultaneous, even though in most of the descriptions the light flashes started at different times, and hit his retinas at different times. In one particular description the light flashes started at the same time, and hit his retinas at the same time.

The revised deduction is that there is only one experience of the events for Albert, and since that matches with our own experiences we can therefore say that there is no longer a paradox.

The paradox is resolved by reassessing the assumption that the sequence of events at Albert's retinas is equal to his experience of the sequence of events in every description of the sequence of events. This is consistent with the theory of special relativity which has been rigorously tested in many experiments, and applying that theory consistently to the whole scenario resolves the paradox.

The very simplified scenario posted originally by Morbert shows this mathematically. The very specific graphs of the scenario posted by Morbert also are not mere illustrative sketches but accurate mathematical graphs of the actual events and show exactly that the perception of the events are simultaneous in both reference frames.

Now, are you trolling us or what?

roosh

Morbert wrote: »

Here you are assuming a mathematical, frame-dependent description is physical.

No, here we are deducing that if an observer sees two flashes of light in sequence, then the photons from those flashes must have physically struck his retinae in sequence, because his brain processes photons which physically strike his retinae, to generate his experience of flashes of light.

Morbert wrote: »

The answer, is no, it does not. By this, I mean if a reference frame, for example, says two events are simultaneous, that does not correspond to reality. Another frame, which says they are not simultaneous, is no more or less correct. Instead, it is an arbitrary description. Similar to the way a frame might describe the set-up as stationary, or moving at some velocity.

In the physical world, Albert's brain generates Albert's experiences by processing stimuli which hit his sensory organs; in the physical world, photons physically strike Albert's retinae; in the physical world, Albert's brain processes sequential experiences of such things as flashes of light; how does Albert's brain generate these sequential experiences of flashes of light, with explicit reference to photons stiking Albert's retinae?

Morbert wrote: »

And we were so close.

So close, yet so far away.

roosh

ceejay wrote: »

At this stage I'm prepared to accept the possibility that roosh is actually just trolling us all
...
Now, are you trolling us or what?

Ah, ya got me! I'm just trolling!

I'm not really though.

ceejay wrote: »

However, just in case you're not -

To state my understanding of your assertion of the paradox, it's the following:

Based on these key assumptions:
- Relativity says that different reference frames result in different descriptions of when the photons hit each retina
- these different descriptions are equally valid descriptions of the order of the real physical events of photons hitting the retinas
- The order of the events at the retinas equals Albert's experience of the order of the events for all descriptions of the sequence of events

I'm not sure about the third one; I would be more inclined to say that the order in which photons physically strike Albert's retinae, while he is on the embankment, dictates the sequence of his experience, of light flashes. Not necessarily his experience of the order of events, for all descriptions of the sequence of events - because I'm not entirely sure what that means, to be honest. If you believe it's the same, then we should be able to proceed with how I've stated it, because, I think, it is a little less wordy and a little easier to understand.

If the different descriptions are a valid representation of the order in which the photons physically strike the retinae, then Albert's brain will process them and generate the corresponding sequential experience.
This produces the following deduction:
- That the difference descriptions of the order of the events create multiple conflicting experiences in Albert's brain of the same two events

ceejay wrote: »

However, Albert clearly doesn't have that kind of experience, he only has one memory of the experience. Hence a paradox arises.

I believe you would agree that the paradox arises because the deduction is false, i.e. people don't have multiple conflicting experiences of the same events, and you are searching for the reason why the deduction is false.

The issue is that we are dealing with an idealised observer in Albert; he's had a prosthetic visual network surgically implanted; this removes any issue of the fallibility of our senses. We can also have a light connected to the "processing centre" of Albert's brain such that it switches on only if the signals from his retinae don't arrive in the order of one first, then the other - this was something dlouth suggested.

So, it's not so much that the deduction is false, such that "we don't have this experience, why don't we have it?" - perhaps our brains just rationalise this away so that we can operate more effectively in the physical world; it's that, given this idealised system, which are are entitled to postulate, a paradox should arise.

ceejay wrote: »

For the deduction to be false one or more of the assumptions must be false:

- The theory of special relativity is incorrect
- The descriptions are not equally valid descriptions of the order of real physical events
- Albert's experience of the order of the events does not equal the order of the events at the retinas for all descriptions of the sequence of the events

There is nothing special about mathemical rerfence frames, I'm sure you will agree; that is, they shouldn't - indeed can't - influence how physical systems operate; they can attempt to offer descriptions of how they operate, but physical systems don't operate according how they are described mathematically. What is of primary importance is how physical systems operate in the physical world.

Albert's experiences of events does equal the order of events at the retinae, in the physical world, not necessarily as they are described; because Albert's brain processes photons which physically strike his retinae, in the physical world, not on the basis of how they are described mathematically.

If the mathematical descriptions correspond to physical events, then it means the photons physically strike in the oder of one first, then the other, and Albert's brain will process them in that order.

ceejay wrote: »

Your posts have been questioning the validity of the second assumption mainly, and also now the first assumption. You consistently assert the third assumption as being true without questioning the validity of that assumption.

If we take the first two assumptions to be true and apply the theory of special relativity rigorously, we find that we have to adjust our common sense view of how Albert's experience of the sequence of events is connected to the sequence of events at his retinas for all descriptions of the sequence of events, and we find that the third assumption is not valid. The way Albert's experience of the sequence events is connected to the sequence of events at the retinas is dependent on which description of the events we are considering.

As outlined above, that wasn't necessarily the assumption; Albert's experience of the sequence of events is connected to the physical events, not necessarily to the descriptions of the events. The mathematical descriptions of the events, of course, aren't physically connected to the events they describe, because the descriptions are abstract; but if the descriptions accurately represent the events they purport to describe, then photons physically strike Albert's retinae in the order of one first, then the other, while he is located on the embankment, if this happens then his brain will generate a sequential experience.

ceejay wrote: »

Based on revising the third assumption we can find what happens to the original deduction:
- In all of the descriptions of the real physical events Albert's experience is that the flashes of light were simultaneous, even though in most of the descriptions the light flashes started at different times, and hit his retinas at different times. In one particular description the light flashes started at the same time, and hit his retinas at the same time.

The revised deduction is that there is only one experience of the events for Albert, and since that matches with our own experiences we can therefore say that there is no longer a paradox.

The assumption you were working off was:
Albert's experience of the order of the events does not equal the order of the events at the retinas for all descriptions of the sequence of the events

This isn't a correct formulation of the assumption though; as mentioned, Albert's experience of the order of events does equal the order of the events at the retinae, in the physical world, not necessarily the order in which they are mathematically described.

ceejay wrote: »

The paradox is resolved by reassessing the assumption that the sequence of events at Albert's retinas is equal to his experience of the sequence of events in every description of the sequence of events. This is consistent with the theory of special relativity which has been rigorously tested in many experiments, and applying that theory consistently to the whole scenario resolves the paradox.

But taking the correct assumption, that the sequence of events at Albert's retinae, in the physical world, does equal the sequence of his experience, not the sequence as described mathematically, the paradox arises again; if, and only if, the mathematical description of the physical events is valid, and corresponds to physical events.

Bear in mind, the assumption, that the processing time of signals from each retinae, to the central processing centre, is the same for both retinae, as far as Albert's brain is concerned, is an assumption taken directly from relativity. This is an important point, because Albert's experiences are generated by Albert's brain, from its own perspective.

The issue arises when we apply this to what we know about what Albert's brain processes in the physical world, namely, photons which physically strike his retinae, while he is standing on the embankment.

There would be no issue except that S' makes a statement about the order in which photons physically strike Albert's retinae.

ceejay wrote: »

The very simplified scenario posted originally by Morbert shows this mathematically. The very specific graphs of the scenario posted by Morbert also are not mere illustrative sketches but accurate mathematical graphs of the actual events and show exactly that the perception of the events are simultaneous in both reference frames.

Indeed, they represent "what relativity says"; but we are taking into account "what the physical world" says also.

Relativity should apply at all points throughout the process, not just certain convenient points.

Morbert

roosh wrote: »

No, here we are deducing that if an observer sees two flashes of light in sequence, then the photons from those flashes must have physically struck his retinae in sequence, because his brain processes photons which physically strike his retinae, to generate his experience of flashes of light.

That is an incorrect deduction. Just because Albert experiences blindness in both eyes simultaneously does not mean his eyes were struck simultaneously.

im invisible

He could have been struck on the back of the head

citrus burst

roosh wrote: »

Using reference frames doesn't necessarily cloud our reasoning; what clouds our reasoning is how we tacitly treat reference frames. S and S' are constituted of mathematical co-ordinates, which don't physically exist, and as such "mahtematical things" physical events cannot happen "in" them; physical events can be described "by" them, but events do not hapen "in" them. When we don't make this expressly clear, then our reasoning can become clouded because both statements means very different things.

If it doesn't cloud our reasoning, then why say it? Retract your statement and make a completely different point?

I agree the coordinates don't exist, but the reference frames do exist. An experiment can be done in a reference frame. You can live in a reference frame. So things can and do happen "in" them. What happen's in them is described by the arbitrarily chosen coordinate system. I could mess around with the coordinate system all I want; change their origin, orientation, even what type of coordinates I want, with out changing how the event actually happened. We usually choose the coordinates that most easily describe the situation, not to say that this is the correct approach.

roosh wrote: »

The physical observer Albert, and his retinae, are represented in S' prime using a set of mathematical co-ordinates; his location on the embankment, at rest relative to it, is represented using a set of mathematical co-ordinates; the physical striking of his retinae, by the photons, while he is standing on the embankment, is represented by mathematical co-ordinates.

I'm not sure I agree with you here. Are you saying that Albert is represented by one reference frame S', with one set of coordinates, call them C. That his location on the embankment, is represented by a different set of coordinates, call them C'. And that the photons hitting his eyes are represented by another coordinate system C''? Or do the coordinates system C represent all of the above in S'?

I really feel you should clarify this as it is of utmost importance.

roosh wrote: »

S' "says" that the photons strike Albert's retinae in the order of one first then the other; if S' corresponds to the physical world, then S' implies that Albert's retinae get struck in the order of one first, then the other.

Ok. You have said this many times.

roosh wrote: »

The ambulance is physical, agreed; the observer standing on the embankment, and the embankment are physical, agreed. But "the ambulance" isn't a representation of the measurements of the relatively moving observer, just as the embankment isn't a representation of the measurements that Albert will, supposedly make; that is the mathematical reference frames S' and S, respectively; S' is not physical, and neither is S.

But the measurements each make are frame dependent. You agree with this?

roosh wrote: »

Why the inverted commas around "physically" and "outside"; this could be misconstrued to mean "not really physically" and "not really outside", but that probably isn't what you meant, but I thought it would be worth hearing a clarifiction.

What I meant was that the person was actually in a different frame, to put emphasis on it.

roosh wrote: »

As you say, "different variables and different consequences"; it is precisely the idea that the actual speed of light is constant, as opposed to just the measured speed, which leads to the conclusion that simultaneity is relative, or that, according to an oberver moving relative to Albert, the photons physically strike Albert's retinae in the order of one first, then the other.

Are you trying to put forward the idea that the actual speed of light is different then the measured speed of light? If it were, this theory and a man called Albert Einstein would never have been heard of.

roosh wrote: »

People seem to be fond of making the analogy to sound, even though the two examples are materially different to the extent that they are not analgous in every way, and certainly not in the manner we are discussing. If we were talking about the colour of light seen by the observers, the analogy might, perhaps, be valid, but we're talking about the order in which photons physically strike an observers retinae, and the order in which the resulting flashes of light are seen by the observer. Alternatively, if the analogy factored in the order in which the eardrums of the observer are stimulated, it might also be valid.

It could be because they are both waves? It could be because they are both different enough that analogies can be drawn from them? It could be that they are both frame dependent? It could simply be that it makes a good every day example of a difficult situation to imagine, such as the loudness of a radio being relative to distance, or the frequency of a siren being relative to velocity. Who knows? In my case I used it to show that the relative velocity of sound to its observer affects the measured frequency of its siren. I used this to show how things can be different for different reference frames. I don't see any issue with this.

roosh wrote: »

Again, it's not the reference frames themselves, per se, which cause the issue to become muddled, it is the use of certain statements about the reference frames which attribute physical characteristics to what are, in essence, non-physical.

What certain statements are these?

roosh wrote: »

Indeed, it is helpful to make the distinction between physical frames of reference and mathematical reference frames, which is what I have endeavoured to do in this discussion, by speaking about physical locations in the physical world and the mathematical representation of the same.

This is the first I've heard of this endeavor. Pretty much up to this point, your fall back argument has been that they are not real. I don't think you have made the connection between physical locations and reference frames. The Earth being one large reference frame, with an associated "unreal" coordinate system known as longitude and latitude.

roosh wrote: »

The emboldened bit is the critical piece of information; they will disagree about which eye physically gets struck first, while Albert is standing on the embankment. Some will say that the photons physically strike the retinae in the order of one first, then the other, while he is standing on the embankment; another observer would say they physically strike in the opposite order, while he is physically standing on the embankment; another observer would say that they physically strike such that they are "tied for first place", on the embankment.

Why is the emboldened part the critical piece of information? I mean if we have 3 reference frames, S, S' and S''. S is the rest frame and S' and S'' are moving relative to S but in opposite directions, then they should disagree what eye got hit first.

You don't seem to have any issue with when I mentioned that if Albert was hit in S non simultaneously then there could be a reference frame that says the light did in fact hit him simultaneously.

roosh wrote: »

As you mention above, relativity says that, despite the disagreement between the observers, that all their measurements correspond to the physical world; that is, the following statements are both true:

They do correspond to the physical world.

roosh wrote: »

- while Albert is standing on the embankment, photons physically strike his retinae in the order of one first, then the other.

For most references frames, moving relative to Albert and the embankment

roosh wrote: »

- while Albert is standing on the embankment, the photons don't physically strike his retinae in the order of one first, then the other, they strike such that they are "tied for first place".

Only for Albert, standing on the embankment, and all others standing on the embankment or at rest relative to the embankment.

roosh wrote: »

Knowing how Albert's brain processes photons which physically strike his retinae, to produce his experiences, while he is standing on the embankment, this leads to the paradoxical situation where he should have discordant experiences of what are supposed to be the same events.

No. Like you have said, Albert's brain doesn't care about what others say about it, only the information it receives.

roosh wrote: »

Of course, if relativity doesn't say that the photons physically strike his retinae in the order of one first, then the other, while he is standing on the embankment, then the description of events given by S' do not correspond to the physical world, where Albert is standing on the embankment and photons physically strike his retinae.

So what you are saying here is that all things observed by moving things aren't physical. That when I get into my car and start driving the events I see do not correspond to the physical world.

roosh wrote: »

Just to reiterate what we are interested in; we're intersted in:
- how Albert's brain operates in the physical world, to produce Albert's experiences

Ok

roosh wrote: »

- how Albert's brain processes photons which physically strike Albert's retinae, while he is standing on the embankment.

Ok this is the same as the previous, just more elaborate. Presumably we also care about when he is not standing on the embankment, ie anywhere else in the universe.

roosh wrote: »

- the physicality of the retinae striking events, as described by both S and S'

By S and S' we mean to relatively moving objects, one of which Albert resides in

roosh wrote: »

Given this information we can make deductions about Albert's experiences, particularly when we idealise Albert and give him a prosthetic visual network which is as infallible as any inanimate system.

ok

roosh wrote: »

We are interested in whether or not the measurements of the relatively moving observer, which lead him to conclude that the photons physically strike Albert's retinae in the order of one first, then the other, while Albert is standing on the embankment are accurate; that is, do the photons physically strike Albert's retinae in the order of one first, then the other, while Albert is standing on the embankment.

I think the physically standing on the embankment is what is causing a lot of issue but I will get to that later.

roosh wrote: »

With that information we can make deductions about Albert's experience, because we know how Albert's brain processes Albert's experiences.

ok

roosh wrote: »

When you say "in Albert's reference frame" do you mean for anyone "standing on the embankment" or, more precisely, "anyone in the physical world who is not physically moving relative to the embankment"?

Yes, perhaps I should have called it Earth's reference frame, S. Where 99.999999% of people have spent all their time. If you aren't moving relative to something, you are in the same reference frame as it.

If you didn't know this, then you truly do not understand reference frames.

roosh wrote: »

Remember that S' is the set of mathematical co-ordinates used to describe events in the physical world; S' =/= the train, becuase the train is physical the co-ordinates aren't; S' is a set of co-ordinates used to describe events as they would supposedly be measured from the train; S' also describes Albert's location on the embankment, at rest relative to it; it describes the events which are the photons physically striking Albert's retinae, and it describes them as physically striking his retinae in the order of one first, then the other.

S and S' are tags we have given to distinguish the coordinates systems of two relatively moving objects. I agree that S' =/= the train, it could be anything really. S' does describe Albert's location, but you have to remember that Albert's location is constantly moving in S'. Similarly the train is constantly moving in S. The seats however are not constantly moving in S'. Similarly the embankment is not moving in S.

roosh wrote: »

However, it's a little more rigorous than that isn't it; relativity says that his measurements lead him to the conclusion that the photons physically strike Albert's retinae in the order of one first, then the other, while Albert is standing on the embankment.

Yes if he is moving relative to Albert, no if he isn't.

roosh wrote: »

If these measurements are accurate, and the photons do physically strike Albert's retinae in the order of one first, then the other, then we know how his brain will process them.

According to a relatively moving observer, not Albert

roosh wrote: »

The measurement of the order depends on the relative motion of the observer, in the physical world; but the measurements supposedly correspond to the physical world; the observer on the train will supposedly make measurements which imply that the photons physically strike Albert's retinae in the given order, while he is standing on the embankment.

Yes, so in Albert's case he isn't moving relative to the set up, he and the set up are in the same reference frame S. So Albert's memories correspond to his measurements.

Remember the other observer is at rest in S' and moving relative to S. Or as you like it, he is sitting on the train, moving relative to Albert and the setup on the embankment. For Albert at rest relative to the set up, the light hits his eyes and his memories are structured accordingly. Everyone else in S will agree. For the other observer, I should also mention that some light is reflected off Albert's eyes, moving relative to the set up and some time after Albert has done his measurement, light arrives at the train and the observer there makes his measurement.

Its as equal as Albert's and corresponds the same as Albert's to the physical world, but it is different then Albert's measurement. It doesn't affect Albert's memories. My memories don't affect yours, yours don't affect mine etc. Albert can use the Lorentz transforms to figure out how separate the two light strikes are for the observer. The observer can use the Lorentz transforms in reverse to figure out how separate the two light strikes are for Albert (in this case he finds they are equal).

The only way the situation could arise were Albert has conflicting memories, is if he is physically in two places at once. That is he is the observer on the train and on the embankment. Since this does not occur in nature there is no paradox in the physical world.

roosh wrote: »

When Albert's brain is processing Albert's experiences, from its location on the embankment, at rest relative to it, it doesn't need to apply the LT to itself.

He does, it just so happens that 0/c = 0 and the square root of 1 is one and you are left with the Newtonian approximation t=t.

roosh wrote: »

We can try and boil it down to a few simple questions, because there are certain things you don't seem to be disputing, and it is directly from those, apparently, undisputes points that our deduction follows. Maybe we can isolate the point of disagreement, a little more specifically.

ok

roosh wrote: »

Do you agree with the the following?

- Albert is physially located on the embankment, at rest relative to it.

Yes we call this S.

roosh wrote: »

- photons physically strike Albert's retinae while he is standing on the embankment.

Yes

roosh wrote: »

- Albert's brain processes all photons which physically strike his retinae, while he is standing on the embankment.

No, but for the sake of this argument I will say yes. His eyes only process visible light, but I am being pedantic.

roosh wrote: »

- if two photons physically strike Albert's retinae in the order of one first, then the other, while he is standing on the embankment, his brain will process an ordered experience that corresponds to the order in which the photons physically strike his retinae.

Yes

roosh wrote: »

- S' "says" that the photons physically strike Albert's retinae in the order of one first, then the other, while he is standing on the embankment.

An observer in s' will say this. I don't know why you need to include the standing on the embankment part.

If we replace Albert with a light bulb. That is if the light from the same two lasers arrives at the same time, the light bulb will turn on, all observers will agree that the bulb turned on, they just won't agree why.

roosh

citrus burst wrote: »

If it doesn't cloud our reasoning, then why say it? Retract your statement and make a completely different point?

It's not the reference frames per se, it's the statements make about the reference frames; so I will retract whatever statement about reference frames was made, that wasn't this, and put this in its stead. One such statement is the statement "in a reference frame", because, as we will discuss below, it seems to conflate the mathematical co-ordinate reference framw, with the physical object that we might refer to as a frame of reference.

citrus burst wrote: »

I agree the coordinates don't exist, but the reference frames do exist. An experiment can be done in a reference frame. You can live in a reference frame. So things can and do happen "in" them. What happen's in them is described by the arbitrarily chosen coordinate system. I could mess around with the coordinate system all I want; change their origin, orientation, even what type of coordinates I want, with out changing how the event actually happened. We usually choose the coordinates that most easily describe the situation, not to say that this is the correct approach.

The mathematical reference frame and the physical reference frame, the trian say, are not the same thing. The mathematical co-ordinates extend beyond the train and "cover" the entire universe, the trian does not. Experiments can be conducted on the train, using it as a frame of reference, but experiments cannot be conducted in mathematical reference frames; the mathematical co-ordinates are used to describe the experiments that take place on the physical train.

citrus burst wrote: »

I'm not sure I agree with you here. Are you saying that Albert is represented by one reference frame S', with one set of coordinates, call them C. That his location on the embankment, is represented by a different set of coordinates, call them C'. And that the photons hitting his eyes are represented by another coordinate system C''? Or do the coordinates system C represent all of the above in S'?

I really feel you should clarify this as it is of utmost importance.

No, all of the above are represented by the co-ordinates of S'; Albert's head will have different co-ordinates to his feet.

citrus burst wrote: »

But the measurements each make are frame dependent. You agree with this?

That depends on what you mean by "frame"; if you mean they are dependent on the set of mathematical co-ordinates which describe them, then no, I don't agree; if you mean are dependent on their location in the physical world, then I do.

citrus burst wrote: »

What I meant was that the person was actually in a different frame, to put emphasis on it.

Ah, OK; for future reference it's probably better to use bold type, or italics for emphasis; inverted commas can suggest that it is being used in a manner that is different to its commonly understood manner, or that the word isn't actually meant - or something to that effect.

citrus burst wrote: »

Are you trying to put forward the idea that the actual speed of light is different then the measured speed of light? If it were, this theory and a man called Albert Einstein would never have been heard of.

LET postulates that the measured speed and the actual speed are different, as far as I know.

citrus burst wrote: »

It could be because they are both waves? It could be because they are both different enough that analogies can be drawn from them? It could be that they are both frame dependent? It could simply be that it makes a good every day example of a difficult situation to imagine, such as the loudness of a radio being relative to distance, or the frequency of a siren being relative to velocity. Who knows? In my case I used it to show that the relative velocity of sound to its observer affects the measured frequency of its siren. I used this to show how things can be different for different reference frames. I don't see any issue with this.

That's all fair enough, but it is obviously limited in its use, and doesn't really address the overall problem we are discussing, of which the point was a part.

citrus burst wrote: »

What certain statements are these?

"Experiments are done in a reference frame", because it can conflate the mathematical set of co-ordinates with the physical location.

citrus burst wrote: »

This is the first I've heard of this endeavor. Pretty much up to this point, your fall back argument has been that they are not real. I don't think you have made the connection between physical locations and reference frames. The Earth being one large reference frame, with an associated "unreal" coordinate system known as longitude and latitude.

I think I've tried to make the distinction between the physical location of an observer e.g. "on the embankment" and the mathematical co-ordinates "used to describe physical events".

The difference between the mathematical co-ordinates and the physical earht is that the mathematical co-ordinates extend beyond the earth.

citrus burst wrote: »

Why is the emboldened part the critical piece of information? I mean if we have 3 reference frames, S, S' and S''. S is the rest frame and S' and S'' are moving relative to S but in opposite directions, then they should disagree what eye got hit first.

The emboldened is the critical piece of information because the observers disagree on which eye physically gets struck first; and we know how Albert's brain processes Albert's experiences; based on how photons, or visible light, physically strike his retinae; adding S'' just compounds the issue.

citrus burst wrote: »

You don't seem to have any issue with when I mentioned that if Albert was hit in S non simultaneously then there could be a reference frame that says the light did in fact hit him simultaneously.

The same issue arises.

citrus burst wrote: »

They do correspond to the physical world.

Then Albert's retinae get struck in the order of one first, then the other, while he is standing on the embankment, and his brain should process an ordered experience from its location on the embankment.

citrus burst wrote: »

For most references frames, moving relative to Albert and the embankment

What do you mean "for most reference frames here"; if we flesh it out to a clearer statement we find that it means that most relatively moving observers will make measurement which imply that Albert's retinae get physically struck by photons, in the order of one first then the other, while he is standing on the embankment.

We add this to what we know about how Albert's brain produces Albert's experiences, for Albert, and our issue arises.

citrus burst wrote: »

Only for Albert, standing on the embankment, and all others standing on the embankment or at rest relative to the embankment.

Different side of the same coin above.

citrus burst wrote: »

No. Like you have said, Albert's brain doesn't care about what others say about it, only the information it receives.

And it receives information from photons which physically strike his retinae; and apparently, photons physically strike his retinae in the order of one first, then the other, while he is standing on the embankment; this is according to the measurements of relatively moving observers, whose measurements are accurate and correspond to the physical world.

citrus burst wrote: »

So what you are saying here is that all things observed by moving things aren't physical. That when I get into my car and start driving the events I see do not correspond to the physical world.

No, I'm saying that, if the photons physicallly strike his retinae in the order of one first, then the other, then his brain will process an ordered experience.

Only if they don't physically strike in that order, will his brain not produce an ordered experience; if they don't physically strike in that order, then the description of S' doesn't correspond to the physical world.

citrus burst wrote: »

Ok this is the same as the previous, just more elaborate. Presumably we also care about when he is not standing on the embankment, ie anywhere else in the universe.

Indeed, but regardless of where he is standing on in the universe, his brain will process his experiences in the same manner; we can even relocate Albert from his location on the embankment and put him on the train which is moving relative to the embankment, and his brain will still process photons in the order they are received, with it taking the same time for signals to reach the processing centre from both retinae; from the perspective of Albert's brain, which is the perspective it produces his experiences from.

citrus burst wrote: »

By S and S' we mean to relatively moving objects, one of which Albert resides in

This is the crux of the issue, the co-ordinate reference frames extend beyond the embankment and are applied to relatively moving objects; they can also be used to represent his meaurements; the embankment, the trees he is at rest relative to, the shop down the road don't represent his measurements.

citrus burst wrote: »

Yes, perhaps I should have called it Earth's reference frame, S. Where 99.999999% of people have spent all their time. If you aren't moving relative to something, you are in the same reference frame as it.

If you didn't know this, then you truly do not understand reference frames.

I do indeed know that, but I also know you can't move relative to mathematical co-ordinates, so here again lies the distinction between the two.

citrus burst wrote: »

S and S' are tags we have given to distinguish the coordinates systems of two relatively moving objects. I agree that S' =/= the train, it could be anything really. S' does describe Albert's location, but you have to remember that Albert's location is constantly moving in S'. Similarly the train is constantly moving in S. The seats however are not constantly moving in S'. Similarly the embankment is not moving in S.

Above, however, you say that S and S' are relatively moving objects, one of which Albert resides in, so there does appear to be a conflation of the mathematical with the physical; which I think causes some problems and can cloud our reasoning.

citrus burst wrote: »

Yes if he is moving relative to Albert, no if he isn't.
...
According to a relatively moving observer, not Albert

But again, this just means that a relatively moving observers measurements imply that photons physically strike Albert's retinae in the order of one first, then the other, while he is standing on the embankment, and the measurements of an observer standing on the emabankment imply that they don't physically strike in that order.

This just gives rise to the issue, knowing what we know about how Albert's brain processes Albert's experiences - from its own perspective; that is, how it processes photons which physically strike his retinae, to generate his experiences, from his own perspective; which is how all his experiences are formed.

citrus burst wrote: »

Yes, so in Albert's case he isn't moving relative to the set up, he and the set up are in the same reference frame S. So Albert's memories correspond to his measurements.

Remember the other observer is at rest in S' and moving relative to S. Or as you like it, he is sitting on the train, moving relative to Albert and the setup on the embankment. For Albert at rest relative to the set up, the light hits his eyes and his memories are structured accordingly. Everyone else in S will agree. For the other observer, I should also mention that some light is reflected off Albert's eyes, moving relative to the set up and some time after Albert has done his measurement, light arrives at the train and the observer there makes his measurement.

Its as equal as Albert's and corresponds the same as Albert's to the physical world, but it is different then Albert's measurement. It doesn't affect Albert's memories. My memories don't affect yours, yours don't affect mine etc. Albert can use the Lorentz transforms to figure out how separate the two light strikes are for the observer. The observer can use the Lorentz transforms in reverse to figure out how separate the two light strikes are for Albert (in this case he finds they are equal).

The only way the situation could arise were Albert has conflicting memories, is if he is physically in two places at once. That is he is the observer on the train and on the embankment. Since this does not occur in nature there is no paradox in the physical world.

What affects Albert's memories are the physical stimuli which enter through his sensory organs, such as light; if light enters through one eye first and then the other, Albert's brain will process an ordered experience. According to the measurements of the relatively moving observer, which are valid and accurate, this is what happens; so Albert's brain should process an ordered experience.

citrus burst wrote: »

He does, it just so happens that 0/c = 0 and the square root of 1 is one and you are left with the Newtonian approximation t=t.

OK, so, this is how his brain processes his experiences when it applies the LT.

citrus burst wrote: »

Yes we call this S.

Again, there appears to be some conflation of the mathematical with the physical here; bear in mind, the mathematical co-ordinates are not the same as the physical location; the mathematical co-ordinates can be used to make calculations and predictions, the physical location cannot; at least, not in the same way.

citrus burst wrote: »

No, but for the sake of this argument I will say yes. His eyes only process visible light, but I am being pedantic.

I think we can substitute in the "blinding laser" there, if there's an issue.

citrus burst wrote: »

An observer in s' will say this. I don't know why you need to include the standing on the embankment part.

The "on the embankment" part is included because this is where the events occur; it's to distinguish it from the relatively moving observer who also has photons strike his retinae in the order of one first, then the other, while he is on the train.

citrus burst wrote: »

If we replace Albert with a light bulb. That is if the light from the same two lasers arrives at the same time, the light bulb will turn on, all observers will agree that the bulb turned on, they just won't agree why.

Yes, but when we include two photoreceptors a distance from the light bulb, and consider how the system process the signals - which it always does from its own perspective - then the order in which the photons physically strike the photoreceptors determines whether or not the buld switches on.

ceejay

Roosh,

Is your question fundamentally about how physically real are the timing of the events from the perspective of relatively moving observers?

Can I ask you to consider a different scenario:

Albert is standing on the embankment using some equipment to measure the frequency of two distant pulsars. Albert selects two pulsars such that their frequencies are equal and their pulses are in sync when he measures them on the embankment.

Next Albert goes into space and travels at a large fraction of the speed of light and measures the same two pulsars. He finds that their frequencies are now different, and they are no longer in sync.

He returns to Earth and repeats his experiments just to be sure, and the pulsars are back in sync with the same frequency.

He wants to be sure that the pulsars aren't changing while he's in space, so he asks his colleague Brian to go into space and measure the pulsars while Albert remains on Earth. Albert's measurements remain the same, they stay in sync and at the same frequency. Brian gets the same results as Albert did when Albert went into space, the pulsars change frequency and go out of sync.

So, are any of the measurements more or less physically real than any of the others?

roosh

ceejay wrote: »

Roosh,

Is your question fundamentally about how physically real are the timing of the events from the perspective of relatively moving observers?

Can I ask you to consider a different scenario:

Albert is standing on the embankment using some equipment to measure the frequency of two distant pulsars. Albert selects two pulsars such that their frequencies are equal and their pulses are in sync when he measures them on the embankment.

Next Albert goes into space and travels at a large fraction of the speed of light and measures the same two pulsars. He finds that their frequencies are now different, and they are no longer in sync.

He returns to Earth and repeats his experiments just to be sure, and the pulsars are back in sync with the same frequency.

He wants to be sure that the pulsars aren't changing while he's in space, so he asks his colleague Brian to go into space and measure the pulsars while Albert remains on Earth. Albert's measurements remain the same, they stay in sync and at the same frequency. Brian gets the same results as Albert did when Albert went into space, the pulsars change frequency and go out of sync.

So, are any of the measurements more or less physically real than any of the others?

Just trying to get a better picture of the scenario; where are the pulsars located with respect to Albert on Earth, are they separated like the rods A and B?

roosh

Morbert wrote: »

Here you are assuming a mathematical, frame-dependent description is physical.

Just plugging the point from the other thread in here, we can say that Albert's brain process photons which physically strike his retinae, while he is standing on the embankment, and it processes them in the order that they strike, without necessarily implying that the order is physical.

S' says that the photons physically strike Albert's retinae while he is standing on the embankment, and that they strike in the order of one first, then the other; so his brain should process an ordered experience.

dlouth15

Roosh, I think at this point if you want to show an inconsistency in special relativity you have to start getting in to the mathematics of it. It is a mathematical theory to start with so any inconsistency will show up mathematically.
For example if you want to show that on the platform we have a situation where Albert (or a simplified model of Albert) both perceives simultaneous and non-simultaneous flashes, then this will be a result of the Lorentz transformation giving two different results for the timing of events happening in the same place.

The problem with using verbal reasoning as you are doing is that you can be led astray easily. A lot of this stuff is counter intuitive initially and the mathematics keeps you on track (if you'll pardon the pun). I outlined how this might be done in another thread and the same applies here.

My recommendation would be to start with the simplified model of Albert i.e. with two light detectors an the processing unit at a point at the centre. In this simplified scenario you need to show that for a given frame, the Lorentz transformation shows that the signals arrive a) at the same time and b) at two different times.

If you can show that you have uncovered a fatal flaw in special relativity.

You may argue that, yes, for this simple system there is no paradox. The paradox arises when you add complexity. What you need to do then is add more processing units. You need to remember, though, that signals must travel at <= c.

You then apply the Lorentz transformation again and see what happens. Remember that you also need to transform the signals as they travel from one processing unit to the others. Do you now get inconsistent results? Keep adding them if necessary until you get an inconsistency. If you do then you have again uncovered a flaw in special relativity and a Nobel prize is surely yours.

Personally I would love to see some inconsistency in a fundamental theory like SR, but I think I would want to see it done in a mathematically rigorous way, especially given the degree to which SR has been tested.

What wouldn't work would be someone verbally stating that it simply can't be the case since it violates their intuition about what should be happening. They might be right but the more likely situation their intuition is wrong and they can't be bothered to do the calculations.

roosh

dlouth15 wrote: »

Roosh, I think at this point if you want to show an inconsistency in special relativity you have to start getting in to the mathematics of it. It is a mathematical theory to start with so any inconsistency will show up mathematically.
For example if you want to show that on the platform we have a situation where Albert (or a simplified model of Albert) both perceives simultaneous and non-simultaneous flashes, then this will be a result of the Lorentz transformation giving two different results for the timing of events happening in the same place.

The problem with using verbal reasoning as you are doing is that you can be led astray easily. A lot of this stuff is counter intuitive initially and the mathematics keeps you on track (if you'll pardon the pun). I outlined how this might be done in another thread and the same applies here.

My recommendation would be to start with the simplified model of Albert i.e. with two light detectors an the processing unit at a point at the centre. In this simplified scenario you need to show that for a given frame, the Lorentz transformation shows that the signals arrive a) at the same time and b) at two different times.

If you can show that you have uncovered a fatal flaw in special relativity.

You may argue that, yes, for this simple system there is no paradox. The paradox arises when you add complexity. What you need to do then is add more processing units. You need to remember, though, that signals must travel at <= c.

You then apply the Lorentz transformation again and see what happens. Remember that you also need to transform the signals as they travel from one processing unit to the others. Do you now get inconsistent results? Keep adding them if necessary until you get an inconsistency. If you do then you have again uncovered a flaw in special relativity and a Nobel prize is surely yours.

Personally I would love to see some inconsistency in a fundamental theory like SR, but I think I would want to see it done in a mathematically rigorous way, especially given the degree to which SR has been tested.

What wouldn't work would be someone verbally stating that it simply can't be the case since it violates their intuition about what should be happening. They might be right but the more likely situation their intuition is wrong and they can't be bothered to do the calculations.

dlouth, this is just the exact same point that has been made all along, which we have been discussing.

Bear in mind that we were using the simplified model of Albert that you suggested, we amalgamated the simplified model with Albert in the form of a prosthetic visual system; we added the light to the top of his head also. You essentially agreed that there was a paradox but you attributed this to the idea that we were choosing a preferred frame for the processing of Albert's experiences. We weren't, however, we were simply stating what we know about how Albert's brain processes Albert's experiences. There was also the implication that there was a paradox for conscious systems, but possibly not for non-conscious systems; but this wasn't established, as the same reasoning holds for the simple system. you suggested, when it was used as Albert's prosthesis as when it was used on its own.


I understand the point that you, and others, have made, about what the mathematics of relativity say; I'm not disputing what the mathematics of relativity say, or the idea that relativity does actually say that a relatively moving observer will measure Albert's brain activity such that the signals converge simultaneously; what I'm saying is that we're not interested in the meaurement of Albert's brain activity by a relatively moving observer, we're interested in how Albert's brain processes Albert's experiences.

We know that Albert's brain processes photons which physically strike his retinae, while he is standing on the embankment; we know that his brain processes them in the order that the physical strikes occur; we know this because Albert has ordered experiences, while he is standing on the platform.

S' says that the photons physically strike Albert's retinae and that the physical strikes occur in the order of one first, then the other; if they do, then Albert's brain will process the physical strikes in the order that the physical strikes occur.

dlouth15

roosh wrote: »

S' says that the photons physically strike Albert's retinae and that the physical strikes occur in the order of one first, then the other; if they do, then Albert's brain will process the physical strikes in the order that the physical strikes occur.

No, and this point has been made several times on this thread.

It is not the order in which the photons strike the receptors that is important but rather the order in which the signals from those receptors reach the central processing unit that determines whether or not the central processing unit detects simultaneity? This is the more fundamental statement.

Do you agree with this?

roosh

dlouth15 wrote: »

No, and this point has been made several times on this thread.

It is not the order in which the photons strike the receptors that is important but rather the order in which the signals from those receptors reach the central processing unit that determines whether or not the central processing unit detects simultaneity? This is the more fundamental statement.

Do you agree with this?

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.

dlouth15

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

roosh wrote: »

[...]

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?

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.