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Question on Lorentz transforms and relativity of simultaneity
Comments
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Agreed.As mentioned, and as per the response to ceejay, Albert's brain will process his experiences in the frame in which it, and he are at rest and where the event took place, that is reference frame S. If light physically hits his eyes simultaneously, then the experience, as processed by the brain, will be of light hitting both eyes simultaneously; if light physically hits both retinae non-simultaneously, then his brain will process the experience accordingly.
It does both, S just happens to be a special case where it is simultaneous and as such his memories would be affected accordingly. In other frames this wont be the case.It's just a question of whether the light physically hits his eyes simultaneously, as per S, or non-simultaneously, as per S';
Again unless he can "simultaneously" be in the doctors office (S) getting his eyes zapped and in a space ship (S') going 0.5c then he will have discordant memories. Fortunately he can't be.if the light physically hits his eyes as per both, then his brian should process discordant experiences.0 -
He is correct to the extent that an observers brain will process physical events in the reference frame in which it, the brain, is at rest. That is, if you are on the embankment, your brain will do it's processing on the embankment, of any sensory input. When light physically hits the retina it becomes input which the brain will process.citrus burst wrote: »Why only to an extent? I know we're not really talking about how the brain processes information but I just want to know why he isn't "fully" right.
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why?
It is just a question of whether the light physically hits your eyes simultaneously, non-simultaneously, or both. According to S the light physically hits your eyes simultaneously; according to S', it physically hits your eyes non-simultaneously.
If both represent real physical events, that is, if the light hitting your retina, as described in S' is a real, physical event, and the light hitting your retina as described by S, is a real, physical event, then your brain should process them as such; the processing will be done by the brain on the embankment.
Indeed, and there could be another reference frame which has the non-simultaneity, of the physical events, as being different from that in S'; this just represents an additional discordant experience that the observer should have.citrus burst wrote: »But there could then be another frame S'' that light hits his eyes simultaneous.
Albert's brain does it's processing of physical events in the frame in which it is at rest; that is, the processing occurs in the rest frame i.e. on the embankment. If light physically hits Albert's eyes, then his brain will process the experience accordingly; if light physically hits Albert's eyes non-simultaneously, then his brain will process the experience accordingly; if light physically hits Albert's eyes simultaneously, then his brain will process the experience accordinglycitrus burst wrote: »True, this is probably the most important thing you have said all thread. The moment light hits his eyes are his experiences. Every other frame is not his experience but somebody or something else's. This is how his memory is correct and not a mixed stew of the memories of all other reference frames. He was never "in" any of them. He can be "described" by all other reference frames, and all other reference frames will agree that the light hit his eyes simultaneous. They will not however observe the light hitting his eyes simultaneous.
This seems totally against common sense and it should be, but if special relativity is correct then it will be the case.
Put another way, Albert's brain will process sensory stimuli according as they are received by the sensory organs; when light physically hits the retina of the eye, that represents the receipt of a sensory stimulus, which the brain will process. The order in which the stimuli are received determines the experience.
According to S' the physical, sensory events - the processing of which takes place in the brains rest frame - that is the light hitting Albert's retinae, occurs non-simultaneously; so if Albert receives physical, sensory stimulation - as he should when light hits his retina - non-simultaneously, his brain will process a non-simultaneous experience.
On the other hand, when the light hits his retinae simultaneously, as it does according to S, his brain will process the simultaneous experience
If the light physically hits his eyes simultaneously, his brain will process the experience accordingly.citrus burst wrote: »yes
yes
No
If the light physically hits his eyes non-simultaneously, his brain will process the experience accordingly.
Does the light physically hit his eyes both simultaneously and non-simultaneously?
Bearing in mind that his brain will do the processing, in the frame in which it is at rest, of all physical events, of light hitting his eyes; and that Albert is physically on the embankment, not physically in the mathematical reference frame labelled S, or S'; where S and S' are mathematical representations, or descriptions, of physical events.
While you may agree with your amendment to the statement, I don't necessarily agree with it. The event takes place on the embankment, where Albert is physically located; S and S' are mathematical representations of the events and, as such, physical events cannot take place in those mathematical reference frames. It is simply a question of whether the mathematical representations correspont to actual, physical events.citrus burst wrote: »Agreed.
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It does both, S just happens to be a special case where it is simultaneous and as such his memories would be affected accordingly. In other frames this wont be the case.
Again, according to the description given by S', the light physically hits Albert's retinae - while Albert is standing on the embankment - non-simultaneously; if this is an accurate representation of physical events, then Albert's brain will process the non-simultaneous events while he is at rest on the embankment.
Only if the light doesn't physically hit Albert's retinae non-simultaneously, while he is physically on the embankment, will his brain not process them as non-simultaneous. If it doesn't physically hit his retinae non-simultaneously, while he is standing on the embankment, then the description of events given by the mathematical reference frame S' - which says that light physically hits his retinae non-simultaneously, while he is standing on the embankment - must not pertain to real, physical events.
Indeed, there is no suggestion that Albert is physically in two places; in this case, he is standing on the embankment only, not on the train whizzing by at relative velocity of 0.98c.citrus burst wrote: »Again unless he can "simultaneously" be in the doctors office (S) getting his eyes zapped and in a space ship (S') going 0.5c then he will have discordant memories. Fortunately he can't be.
The mathematical reference frame S says that light physically hits his retinae simultaneously, while he is physically standing on the embankment. S' says that, while he is physically standing on the embankment, the light hits his eyes non-simultaneously.
If light hits his eyes simultaneously, while he is standing on the embankment, then his brain will process the simultaneous experience; if light hits his eys non-simultaneously, while he is standing on the embankment, then his brain will process a non-simultaneous experience.
If both mathematical representations, of light physically hitting his retinae, while he is physically standing on the embankment, are valid, correct, true, or whatever term we care to use, then his brain will process discordant experiences of what are, supposedly, the same phenomenon.
Only if the light doesn't physically hit his eyes, non-simultaneously (for arguments sake), while he is physically standing on the embankment, will his brain not process discordant experiences.0 -
We can idealise the observer, can't we, to make the effect more noticeable; we can make Albert into "Giant Albert", or like Gulliver in the land of Liliput?0
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Look at this again:Try the transformations explicitly yourself. Let's say the rods a and b are each 1 lightsecond (ls) away from the observer in the middle. In the reference frame of the observer, we have:
Time of strikes is Ta =Tb = 0 s
Position of rod a is Xa = 1 ls
Position of rob b is Xb = -1 ls
Time strike a is witnessed is ta = 1 s
Time strike b is witnessed is tb = 1 s
The strikes are both witnessed at position x = 0 ls
Now let's transform the coordinates to a reference frame travelling at v relative to the observer. We'll use natural units, so that c = 1.
The time of strikes are
Ta' = γ(Ta-vXa) = -γv
Tb = γ(Tb-vXb) = γv
But the strikes are witnessed at
ta' = γ(ta-vx) = γ
tb' = γ(tb-vx) = γ
So you see that, even though the strikes are not simultaneous, all reference frames will agree that you witness both strikes simultaneously. Hence, causality is preserved.
Morbert uses the mathematics to describe the situation generically but also exactly. What the maths above shows is that in the rest frame the lightning strikes at points A and B happen simultaneously at t = 0 seconds, and that you see them simultaneously at t = 1 seconds because you are standing in the middle at a distance of 1 light second away from each rod.
From the maths above again using the results of the transformations, these show that in the moving frame the lightning strikes at A and B are no longer simultaneous - the strike at A happens at t = -γv seconds, and the strike a B happens at t = γv seconds, instead of them both happening at t = 0 seconds. In the moving frame of reference there is 2γv seconds between the two lightning strikes.
More significantly: even in the moving frame of reference the light from both lightning strikes still arrive at your position in the middle simultaneously though it is measured in the moving frame of reference as happening at t = γ seconds instead of at t = 1 seconds.
As you vary the chosen speed for the moving reference frame the separation in time between the two lightning flashes will change, and the precise moment when they simultaneously arrive at you standing in the middle will change, but the maths show that the light will always arrive simultaneously at you standing in the middle no matter what reference frame you use!
So there is no discordant memory situation to worry about
I must admit that I had missed the significance of this when I first read Morbert's post.0 -
As mentioned, and as per the response to ceejay, Albert's brain will process his experiences in the frame in which it, and he are at rest. If light physically hits his eyes simultaneously, then the experience, as processed by the brain, will be of light hitting both eyes simultaneously; if light physically hits both retinae non-simultaneously, then his brain will process the experience accordingly.
You keep saying this, and it will not be true no matter how many times you do. In S', the experience processed by the brain is still of being blinded in both eyes simultaneously. This is because in S', brain activity itself exhibits RoS. You are consistently ignoring this point.0 -
This assumes that the photons converge at the same point; the point being made is that the retina are not located at the same point, there is a distance between them such that, according to S', the light will hit the retina non-simultaneously.Look at this again:
Morbert uses the mathematics to describe the situation generically but also exactly. What the maths above shows is that in the rest frame the lightning strikes at points A and B happen simultaneously at t = 0 seconds, and that you see them simultaneously at t = 1 seconds because you are standing in the middle at a distance of 1 light second away from each rod.
From the maths above again using the results of the transformations, these show that in the moving frame the lightning strikes at A and B are no longer simultaneous - the strike at A happens at t = -γv seconds, and the strike a B happens at t = γv seconds, instead of them both happening at t = 0 seconds. In the moving frame of reference there is 2γv seconds between the two lightning strikes.
More significantly: even in the moving frame of reference the light from both lightning strikes still arrive at your position in the middle simultaneously though it is measured in the moving frame of reference as happening at t = γ seconds instead of at t = 1 seconds.
As you vary the chosen speed for the moving reference frame the separation in time between the two lightning flashes will change, and the precise moment when they simultaneously arrive at you standing in the middle will change, but the maths show that the light will always arrive simultaneously at you standing in the middle no matter what reference frame you use!
So there is no discordant memory situation to worry about
I must admit that I had missed the significance of this when I first read Morbert's post.0 -
Albert's brain isn't in S'; Albert's brain is with him on the embankment. Albert's brain will do its processing on the embankment, not in a relatively moving train. Albert's brain will process physical stimuli according as they are received.You keep saying this, and it will not be true no matter how many times you do. In S', the experience processed by the brain is still of being blinded in both eyes simultaneously. This is because in S', brain activity itself exhibits RoS. You are consistently ignoring this point.
S' says that the photons will hit Albert's retina, on the embankment, non-simultaneously; that is, S' says the physical stimuli will enter his retinae non-simultaneously, on the embankment. If senosry input enters Albert's retinae non-simultaneously, on the embankment, then his brain will process a non-simultaneous experience, on the embankment.
S says that the sensory stimuli will be received simultaneously, on the embankment; that is, S says the physical stimuli will enter his retinae simultaneously, on the embankment. If senosry input enters Albert's retinae simultaneously, on the embankment, then his brain will process a simultaneous experience, on the embankment.
It's just a question of whether he receives the physical, sensory stimuli simultaneously, non-simultaneously, or both, on the embankment; S says he will receive them simultaneously, on the embankment; S' says non-simultaneously, on the embankment. If both are valid representations of the physical, sensory stimuli, then his brain should produce discordant experiences of the received photons, on the embankment.0 -
Albert's brain isn't in S'; Albert's brain is with him on the embankment. Albert's brain will do its processing on the embankment, not in a relatively moving train. Albert's brain will process physical stimuli according as they are received.
S' says that the photons will hit Albert's retina, on the embankment, non-simultaneously; that is, S' says the physical stimuli will enter his retinae non-simultaneously, on the embankment. If senosry input enters Albert's retinae non-simultaneously, on the embankment, then his brain will process a non-simultaneous experience, on the embankment.
S says that the sensory stimuli will be received simultaneously, on the embankment; that is, S says the physical stimuli will enter his retinae simultaneously, on the embankment. If senosry input enters Albert's retinae simultaneously, on the embankment, then his brain will process a simultaneous experience, on the embankment.
It's just a question of whether he receives the physical, sensory stimuli simultaneously, non-simultaneously, or both, on the embankment; S says he will receive them simultaneously, on the embankment; S' says non-simultaneously, on the embankment. If both are valid representations of the physical, sensory stimuli, then his brain should produce discordant experiences of the received photons, on the embankment.
You still clearly don't understand how reference frames are applied. S and S' are two different sets of labels in which we consider the relevant events. What you are doing is considering the lights striking the eyes in S', but refusing to consider the brain activity in S' at each strike. This is a blatantly inconsistent use of coordinate labels. I do not know how to make this point any simpler.
Take this simplification: Instead of eyes, consider two synchronised clocks separated by an arbitrary distance, each equally close to a respective rod. In S, both clocks are struck by the respective lasers simultaneously, and register this. In S', the clocks are struck at different times, but they are also no longer synchronous. The clock struck first is a little ahead of the other. Thus, both clocks register the same time, even though they were struck at different times. You are saying "oh but the clocks aren't in S', they're in S." which is a nonsensical statement.
[edit]- Removed confusing sentence.0 -
I understand how reference frames are applied; this line of questioning, in part, questions the validity of how they are applied. What we are looking at here is the physicality of the events, as represented by the mathematical reference frames, and how Albert's brain processes physical stimuli which hit his retinae.You still clearly don't understand how reference frames are applied. S and S' are two different sets of labels in which we consider the relevant events. What you are doing is considering the lights striking the eyes in S', but refusing to consider the brain activity in S' at each strike. This is a blatantly inconsistent use of coordinate labels. I do not know how to make this point any simpler.
Take this simplification: Instead of eyes, consider two synchronised clocks separated by an arbitrary distance, each equally close to a respective rod. In S, both clocks are struck by the respective lasers simultaneously, and register this. In S', the clocks are struck at different times, but they are also no longer synchronous. The clock struck first is a little ahead of the other. Thus, both clocks register the same time, even though they were struck at different times. You are saying "oh but the clocks aren't in S', they're in S." which is a nonsensical statement.
[edit]- Removed confusing sentence.
We can stick with the thought experiment as is, considering Albert's eyes and brain; we can augment it to say that Albert is in the army and is awaiting instructions as to whether or not to blow up a bridge; his instructions are, if you receive the signals simultaneously, blow up the bridge, if you receive the signals non-simultaneously, do not blow up the bridge.
Albert is physically standing on the embankment; he's not in either S or S'; S and S' are simply mathematical representations of physical events. Albert's brain will process any physical stimuli received by his retinae from its location on the embankment; his brain doesn't process his experiences by viewing itself from a relatively moving reference frame. That is, as soon as physical stimulae enter Albert's retinae, his brain processes as though it is not subject to relativistic effects, because, as far as it is concerned, it isn't.
So, picture Albert standing on the embankment; now picture two photons hitting his retinae simultaneously; his brain will process the sensory stimuli and produce the simultaneous experience which informs him to blow up the bridge.
Again, picture Albert standing on the embankment; now, picture two photons hitting his retinae non-simultaneously; his brain will process the sensory stimuli and produce the non-simultaneous experience, which informs him not to blow up the bridge.
According to relativity, Albert receives the sensory information both simultaneously and non-simultaneously; from there it follows that his brain should produce discordant experiences and he should both blow up the bridge and not blow up the bridge.
EDIT: essentially the point you are making, by saying that Albert's brain undergoes relativistic effects, is that Albert's brain will process physical stimuli which are received through his retinae, from the perspective of a relatively moving observer; in other words, that Albert will process his experiences from the perspective of a relatively moving observer.
We might say that, from the perspective of a relatively moving observer, Albert's brain is measured to undergo relativistic effects, but Albert's won't process his experiences from the relatively moving observers perspective; if we say that the photons are only measured to hit Albert's retinae non-simultaneously, by a relatively moving observer, then we open the question as to whether or not the photons physically hit Albert's retinae simultaneously, or if there is an anomaly in the relatively moving observers measurements that mean his measurements don't represent the physical events, that is the photons hitting the retinae [non-simultaneously].
If the photons do physically hit the retinae non-simultaneously, then Albert's brain won't process them from the perspective of a relatively moving observer.0 -
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I understand how reference frames are applied; this line of questioning, in part, questions the validity of how they are applied. What we are looking at here is the physicality of the events, as represented by the mathematical reference frames, and how Albert's brain processes physical stimuli which hit his retinae.
We can stick with the thought experiment as is, considering Albert's eyes and brain; we can augment it to say that Albert is in the army and is awaiting instructions as to whether or not to blow up a bridge; his instructions are, if you receive the signals simultaneously, blow up the bridge, if you receive the signals non-simultaneously, do not blow up the bridge.
Albert is physically standing on the embankment; he's not in either S or S'; S and S' are simply mathematical representations of physical events. Albert's brain will process any physical stimuli received by his retinae from its location on the embankment; his brain doesn't process his experiences by viewing itself from a relatively moving reference frame. That is, as soon as physical stimulae enter Albert's retinae, his brain processes as though it is not subject to relativistic effects, because, as far as it is concerned, it isn't.
So, picture Albert standing on the embankment; now picture two photons hitting his retinae simultaneously; his brain will process the sensory stimuli and produce the simultaneous experience which informs him to blow up the bridge.
Again, picture Albert standing on the embankment; now, picture two photons hitting his retinae non-simultaneously; his brain will process the sensory stimuli and produce the non-simultaneous experience, which informs him not to blow up the bridge.
According to relativity, Albert receives the sensory information both simultaneously and non-simultaneously; from there it follows that his brain should produce discordant experiences and he should both blow up the bridge and not blow up the bridge.
EDIT: essentially the point you are making, by saying that Albert's brain undergoes relativistic effects, is that Albert's brain will process physical stimuli which are received through his retinae, from the perspective of a relatively moving observer; in other words, that Albert will process his experiences from the perspective of a relatively moving observer.
We might say that, from the perspective of a relatively moving observer, Albert's brain is measured to undergo relativistic effects, but Albert's won't process his experiences from the relatively moving observers perspective; if we say that the photons are only measured to hit Albert's retinae non-simultaneously, by a relatively moving observer, then we open the question as to whether or not the photons physically hit Albert's retinae simultaneously, or if there is an anomaly in the relatively moving observers measurements that mean his measurements don't represent the physical events, that is the photons hitting the retinae [non-simultaneously].
If the photons do physically hit the retinae non-simultaneously, then Albert's brain won't process them from the perspective of a relatively moving observer.
You continue to blatantly ignore everything I have said. Here is the important point again: In S', the experience processed by the brain is still of being blinded in both eyes simultaneously. This is because in S', brain activity itself exhibits RoS. So even though the Albert isn't struck simultaneously in S', his brain will still register simultaneous strikes for the same reason two clocks would register simultaneous strikes. You are consistently ignoring this point.
So in your new, completely superfluous and irrelevant augmented thought experiment, both reference frames would agree that Albert blows up the bridge.0 -
I'm not ignoring it, it just doesn't address the issue.You continue to blatantly ignore everything I have said. Here is the important point again: In S', the experience processed by the brain is still of being blinded in both eyes simultaneously. This is because in S', brain activity itself exhibits RoS. So even though the Albert isn't struck simultaneously in S', his brain will still register simultaneous strikes for the same reason two clocks would register simultaneous strikes. You are consistently ignoring this point.
So in your new, completely superfluous and irrelevant augmented thought experiment, both reference frames would agree that Albert blows up the bridge.
Do you disagree with the following:
if two photons physically hit his retinae simultaneously, while he is standing on the embankment, then his brain will produce a simultaneous experience; if two photons hit his retinae non-simultaneously, while he is standing on the embankment, then his brain will produce a non-simultaneous experience?0 -
I'm not ignoring it, it just doesn't address the issue.
Do you disagree with the following:
if two photons physically hit his retinae simultaneously, while he is standing on the embankment, then his brain will produce a simultaneous experience; if two photons hit his retinae non-simultaneously, while he is standing on the embankment, then his brain will produce a non-simultaneous experience?
Yes I disagree. The above is true in S but not in S'.0 -
We're not talking about either S or S' and we haven't specified which photons we're talking about; we're talking about how Albert's brain processes sensory information, that leads to Albert's experiences.Yes I disagree. The above is true in S but not in S'.
Maybe if we personalise it a bit;
do you agree, that if two photons physically hit your retinae simultaneously, while you are standing on an embankment, at rest relative to it, that your brain will produce a simultaneous experience?
Do you agree that if two photons physically hit your retinae non-simultaneously, while you are standing on an embankment, at rest relative to it, that your brain will produce a non-simultaneous experience?
Is this true or false for all physical photons?0 -
We're not talking about either S or S' and we haven't specified which photons we're talking about; we're talking about how Albert's brain processes sensory information, that leads to Albert's experiences.
Yes we are talking about S and S'. What is and isn't "simultaneous" depends on what reference frame you are using.Maybe if we personalise it a bit;
do you agree, that if two photons physically hit your retinae simultaneously, while you are standing on an embankment, at rest relative to it, that your brain will produce a simultaneous experience?
Do you agree that if two photons physically hit your retinae non-simultaneously, while you are standing on an embankment, at rest relative to it, that your brain will produce a non-simultaneous experience?
Is this true or false for all physical photons?
Which reference frame are you referring to? If the strikes are simultaneous, as defined by S, then my brain will produce a "simultaneous" experience. The same is not true for simultaneous strikes as defined by S', however.0 -
Consider this - for the brain to determine whether or not the retinas were stimulated by the photons at the same time or not, a signal must pass from each retina to some location in the brain which performs whatever operation is needed to compare two signals. So whether you're talking about retinas being stimulated and being assessed by an organic brain or some other light detecting devices with maybe some electronics comparing the signals, my point is that the comparison and the experience of simultaneity happens at a single location, and not two physically distinct locations. So the maths earlier show that the perception of the event will be that it is simultaneous no matter what reference frame you're using.
Think of it more abstractly in terms of information, and how you could come to a decision about two pieces of information - you need to have the two pieces of info to hand to make a determination. The maths effectively show that if you observe the events simultaneously in your rest frame, other moving observers will also conclude that you observe them simultaneously, though not at the same moment in time. The light hitting the retinas is not enough for an observation, there has to be additional time for information to be passed somewhere to check for simultaneity.
Also consider Occam's Razor applied to the situation: If your reasoning was sound then you could pick an infinite set of reference frames which would create whatever variation in time between events which in one particular frame of reference you would agree that they are simultaneous, and so in real life we would have many (possibly infinite) conflicting experiences of when things happen and in what order. Clearly that is not the case (at least not for me!), so therefore your reasoning is not sound, and humans do not experience multiple conflicting versions of events.
You don't seem to want to accept what the maths says, that if two photons arrive at a point in space at the same time as expressed in one frame of reference, then all other reference frames will show that the two photons will still meet at that point in space at some instant, it's just when that instant is that won't be the same in the different frames of reference.0 -
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What we're interested in here, is not necessarily what other observers will conclude, we're interested in how Albert's brain processes his experiences.Consider this - for the brain to determine whether or not the retinas were stimulated by the photons at the same time or not, a signal must pass from each retina to some location in the brain which performs whatever operation is needed to compare two signals. So whether you're talking about retinas being stimulated and being assessed by an organic brain or some other light detecting devices with maybe some electronics comparing the signals, my point is that the comparison and the experience of simultaneity happens at a single location, and not two physically distinct locations. So the maths earlier show that the perception of the event will be that it is simultaneous no matter what reference frame you're using.
Think of it more abstractly in terms of information, and how you could come to a decision about two pieces of information - you need to have the two pieces of info to hand to make a determination. The maths effectively show that if you observe the events simultaneously in your rest frame, other moving observers will also conclude that you observe them simultaneously, though not at the same moment in time. The light hitting the retinas is not enough for an observation, there has to be additional time for information to be passed somewhere to check for simultaneity.
Also consider Occam's Razor applied to the situation: If your reasoning was sound then you could pick an infinite set of reference frames which would create whatever variation in time between events which in one particular frame of reference you would agree that they are simultaneous, and so in real life we would have many (possibly infinite) conflicting experiences of when things happen and in what order. Clearly that is not the case (at least not for me!), so therefore your reasoning is not sound, and humans do not experience multiple conflicting versions of events.
You don't seem to want to accept what the maths says, that if two photons arrive at a point in space at the same time as expressed in one frame of reference, then all other reference frames will show that the two photons will still meet at that point in space at some instant, it's just when that instant is that won't be the same in the different frames of reference.
Let's ignore the issue of relativity of simultaneity for a second, and focus on how Albert's brain processes physical stimuli, when those stimuli reach him in his position on the platform.
Let's say a photon hits his right retina first, and then five minutes later, a photon hits his left eye; will his brain process the information and produce a simultaneous experience? No, it won't, it will produce a non-simultaneous experience. This is because Albert's brain processes physical stimuli in the order they are received. This must be true for all photons which physically strike his retinae, or else we can conclude that there is a difference in the physicality of the photons.
Now, back to RoS. S' says that the photons physically hit Albert's retinae non-simultaneously; now, as above, Albert's brain should process a non-simultaneous experience, if those photons are real, and physical.
If we say that they only strike hit retinae non-simultaneously from the perspective of a relatively moving observer, then we are denying the physicality of the events as they strike Albert's retinae; because, as we have seen above, Albert's brain processes stimuli in the order they are received to produce his experiences, not the experience of a relatively moving observer.
The point about Occam's Razor is simply evidence that the photons don't strike his retinae both simultaneously and non-simultaneously; because, if they did, they would produce two discordant experiences.
It might be helpful to imagine yourself on the embankment, and imagine two photons striking your retinae simultaneously; ask yourself, how would your brain process the experience for you?
Now imagine that two photons strike your retinae non-simultaneously; ask, how would your brain process the experience for you - not for some relatively moving observer?0 -
Let's say a photon hits his right retina first, and then five minutes later, a photon hits his left eye; will his brain process the information and produce a simultaneous experience?
No, this is what happens. Your brain creates the illusion of simultaneity. Because your brain response are so slow relative to different nerve responses in your body. Your brain knows that you need the illusion of simultaneity, so your world doesn't fell wobbly - so that's the illusion it gives you.
If I hit your knee, with a hammer, and you could see me do it. You would feel pain simultaneously to the hammer strike - this is your brain creating an illusion. If I did the hammer strikes without you seeing, you'd feel the pain 100, to even 200 milliseconds later - which sounds short but is really noticeable. Your brain cooks things up, so they look simultaneous even when they are not.
Simultaneity, even within a frame, is a illusion.0 -
If we ignore the thought experiment for a moment and just talk about how the brian processes information; if we take two random photons which physically hit our retinae non-simultaneously; that is, the left retina first and then the right retina. Our brain will process this sensory information in the order they are received. We know this, because not every single sensory experience is processed as a simultaneous events.No, this is what happens. Your brain creates the illusion of simultaneity. Because your brain response are so slow relative to different nerve responses in your body. Your brain knows that you need the illusion of simultaneity, so your world doesn't fell wobbly - so that's the illusion it gives you.
If I hit your knee, with a hammer, and you could see me do it. You would feel pain simultaneously to the hammer strike - this is your brain creating an illusion. If I did the hammer strikes without you seeing, you'd feel the pain 100, to even 200 milliseconds later - which sounds short but is really noticeable. Your brain cooks things up, so they look simultaneous even when they are not.
Simultaneity, even within a frame, is a illusion.
So, we know that the brain will process sensory information in the order it is received, in general; we can, of course, use idealised observers and instruments in our thought experiments, so that we can avoid conclusions such as, relativity is true because our senses deceive us. But we know anyway, that all experiences aren't processed as simultaneous, so we know that there is an ordering anyway - I don't think the reflex analogy is the same as light being received through the retinae, anway, because the light has to travel the same distance to be processed in both cases.
Knowing that our brain will process photons, which are physically received through the retinae, in the order they are received, we can ask, is this true for all photons, or just for some?0 -
If this is the case, then the following is redundant.What we're interested in here, is not necessarily what other observers will conclude, we're interested in how Albert's brain processes his experiences.
Usually in the order it is received.Let's ignore the issue of relativity of simultaneity for a second, and focus on how Albert's brain processes physical stimuli, when those stimuli reach him in his position on the platform.
No because there is a time difference between the two photons. So why would he think they happened at the same time?Let's say a photon hits his right retina first, and then five minutes later, a photon hits his left eye; will his brain process the information and produce a simultaneous experience? No, it won't, it will produce a non-simultaneous experience. This is because Albert's brain processes physical stimuli in the order they are received. This must be true for all photons which physically strike his retinae, or else we can conclude that there is a difference in the physicality of the photons.
See now you have thrown in an extra reference frame. At the start you just wanted to know what Albert observed. Albert makes his observation in S and as such has memories accordingly. How would S' have any bearing on Albert's memory/observation etc?Now, back to RoS. S' says that the photons physically hit Albert's retinae non-simultaneously; now, as above, Albert's brain should process a non-simultaneous experience, if those photons are real, and physical.
Drop something on a train, you see it fall in a straight line (you're on the train by the way). I'm on the platform. I see if fall in a parabolic fashion. How does my observation/memory in any way affect yours?
Now expand this to light and high velocities and once again what S' observes should have no bearing on what S observes.
No we are not. Like you said "Albert's brain processes stimuli in the order they are received to produce his experiences." They are observed, in this case, where Albert makes his measurement, simultaneous in S. Therefore Albert's brain is stimulated in such a way that his memory recalls being hit by both photon at the same time.If we say that they only strike hit retinae non-simultaneously from the perspective of a relatively moving observer, then we are denying the physicality of the events as they strike Albert's retinae; because, as we have seen above, Albert's brain processes stimuli in the order they are received to produce his experiences, not the experience of a relatively moving observer.
Again as you said "not the experience of a relatively moving observer." So why would his memories be in any way affected by S'. This line here pulls down your whole argument and logic.
They do in fact produce an infinite amount of experiences, not just two, but we are only using two reference frames. Why would the observations of one reference frame affect the observations of another and hence memory? Or as you put it:The point about Occam's Razor is simply evidence that the photons don't strike his retinae both simultaneously and non-simultaneously; because, if they did, they would produce two discordant experiences.Albert's brain processes stimuli in the order they are received to produce his experiences, not the experience of a relatively moving observer.
So either you do not understand the concept fully or you are arguing for the sake of arguing. You've managed to pick apart your own argument, yet still refuse to accept what you've been told countless times in this thread alone.It might be helpful to imagine yourself on the embankment, and imagine two photons striking your retinae simultaneously; ask yourself, how would your brain process the experience for you?
You've already answered this yourself. The point of relativity of simultaneity is that in general, something that is simultaneous in one reference frame will not be simultaneous in another.
This has absolutely no bearing on the physicality of observed events. Just the order in which they happen, as observed by a reference frame.
Again you've answered this yourself.Now imagine that two photons strike your retinae non-simultaneously; ask, how would your brain process the experience for you - not for some relatively moving observer?0 -
Now, back to RoS. S' says that the photons physically hit Albert's retinae non-simultaneously; now, as above, Albert's brain should process a non-simultaneous experience, if those photons are real, and physical.
I have already addressed this. S' says the photons hit Albert's retinae non-simultaneously. But since the brain is an extended object, S' also says simultaneity in brain activity is not the same as in S. Hence, S' says the photons hit non-simultaneously, and S' says Albert experiences this as being simultaneously blinded in both eyes.
So both S and S' agree with what physically happens.0 -
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This post is quite long, so it might be possible to take a different line, which starts with a very, very simple premise; a premise I presume you'll have no choice but to agree with; namely:
Albert is an observer in Albert's reference frame.
We can take that an progress from there if needs, be, but I've addressed the points raised below.
Not necessarily, because are are interested in the physicality of the events as described by other reference frames.citrus burst wrote: »If this is the case, then the following is redundant.
OK, so when photons make physical contact with Albert's retinae, his brain will process them in the order they are received.citrus burst wrote: »Usually in the order it is received.
We're just establishing a few things first about how Albert's brain processes photons which physically make contact with his retinae.citrus burst wrote: »No because there is a time difference between the two photons. So why would he think they happened at the same time?
Also, we don't need to worry about the "time" difference between the photons, we only need to consider that non-simultaneous means that one physically makes contact with the retinae before the other, such that we could label them in the order they are received i.e. 1 and 2.
In the beginning we just wanted to establish how Albert's brian processes photons which make phyiscal contact with his retinae; as you said above, usually in the order they are received.citrus burst wrote: »See now you have thrown in an extra reference frame. At the start you just wanted to know what Albert observed. Albert makes his observation in S and as such has memories accordingly. How would S' have any bearing on Albert's memory/observation etc?
We introduce the second reference frame because we are interested in the physicality of the events in that reference frame; bearing in mind how Albert's brain processes photons which make physical contact with his retinae.
This is a somewhat different example, because it doesn't involve photons making physical contact with our retinae - we can felsh it out so that it does, but then we have the same issue as we have been discussing.citrus burst wrote: »Drop something on a train, you see it fall in a straight line (you're on the train by the way). I'm on the platform. I see if fall in a parabolic fashion. How does my observation/memory in any way affect yours?
No, but the physicality of the events does have a bearing on what the "stationary" observer, or Albert observes; given what we know about how Albert's brain will process photons which physically make contact with his retinae.citrus burst wrote: »Now expand this to light and high velocities and once again what S' observes should have no bearing on what S observes.
We can put away the metre sticks and clocks, because we're not interested in what Albert measures with his measuring instruments, we are interested in how his brain processes his experiences. As we have established, Albert's brain will process photons which physically make contact with his retinae, in the order they are received.citrus burst wrote: »No we are not. Like you said "Albert's brain processes stimuli in the order they are received to produce his experiences." They are observed, in this case, where Albert makes his measurement, simultaneous in S. Therefore Albert's brain is stimulated in such a way that his memory recalls being hit by both photon at the same time.
According to S', the photons physically make contact with Albert's retinae non-simultaneously; that is, one physically makes contact with the right retina, for arguments sake, before the other physically makes contact with the left retina.
Given what we know about how Albert's brain processes photons which physically make contact with his retinae - in the order they are received - if the photons physically make contact with his retinae in such a way that one physically makes contact before the other, Albert's brain should process them in that order and produce a non-simultaneous experience.
Remembering that as far as Albert's brain is concerned, when it is processing Albert's experiences, the distance and time it takes for all photons which physically make contact with his retinae, or the signals which originate in the retinae, to reach any idealised "processing centre", is the same for both retinae; such that, if a pair of photons make physical contact with Albert's retinae, such that one arrives first and the other second, then his brain will process them to produce a non-simultaneous experience.
Or so it would seem; but it's the physicality of the events as described by S' which we are interested in; S' says that the photons make physical contact with Albert's retinae non-simultaneously, in the physical world, where Albert is standing on the embankment.citrus burst wrote: »Again as you said "not the experience of a relatively moving observer." So why would his memories be in any way affected by S'. This line here pulls down your whole argument and logic.
We know how Albert's brain processes all photons, which make physical contact with his retinae, to produce his experiences - as opposed to how a relativley moving observer will - supposedly - measure Albert's brian activity and the conclusion that relatively moving observer will - supposedly - arrive at, with regard to Albert's experiences.
Not for the same observer, as we can reason they should, given how we know how an observers brain processes physical stimuli which make physical contact with their retinae, for example.citrus burst wrote: »They do in fact produce an infinite amount of experiences, not just two, but we are only using two reference frames. Why would the observations of one reference frame affect the observations of another and hence memory? Or as you put it:
The observations of one reference frame would affect the experiences of another if the observations of that other "reference frame" pertain to photons which make physical contact with the other observers retinae.
I understand the concept, I'm just highlighting an example of how it cannot correspond to the physical world.citrus burst wrote: »So either you do not understand the concept fully or you are arguing for the sake of arguing. You've managed to pick apart your own argument, yet still refuse to accept what you've been told countless times in this thread alone.
and that all events as represented by the various reference frames correspond to real, physical events; such that, one reference frame says that photons make physical contact with an observers retinae simultaneously the other says that they make physical contact non-simultaneously.citrus burst wrote: »You've already answered this yourself. The point of relativity of simultaneity is that in general, something that is simultaneous in one reference frame will not be simultaneous in another.
We know how an observers brain processes photons which make physical contact with the observers retinae, in the physical world, and that is how we arrive at our conclusion.
The only question is, do the events in S' correspond to real physical events; that is, do the photons physically make contact with Albert's retinae in the order of one first, then the other? Because if they do, then this is the order in which Albert's brain will process them, to produce Albert's experiences; because that is how Albert's brain processes ALL photons which make phyiscal contact with his retinae.
No, but the physicality of events, and the order they are received, does have a bearing on how an observer's brian will process them; in fact, it dictates how the brain will process them.citrus burst wrote: »This has absolutely no bearing on the physicality of observed events. Just the order in which they happen, as observed by a reference frame.
And hopefully any other perceived issues.citrus burst wrote: »Again you've answered this yourself.0 -
And I have addressed this already, but I've no problem trying to clarify it until it is understood.I have already addressed this. S' says the photons hit Albert's retinae non-simultaneously. But since the brain is an extended object, S' also says simultaneity in brain activity is not the same as in S. Hence, S' says the photons hit non-simultaneously, and S' says Albert experiences this as being simultaneously blinded in both eyes.
So both S and S' agree with what physically happens.
We know how Albert's brian processes Albert's experiences; if photons make physical contact with his retinae, then his brian will process them in the order they arrive. For Albert's brain, when it is producing Albert's experiences, the distance and time it takes for physical stimuli to reach an idealised "processing centre" is the same for both retinae. This is how Albert's experiences are produced, by Albert's brain, while he is physically standing on the embankment.
The only question which remains pertains to the physicality of the photons which make physical contact with his retinae, in the physical world, while he is physically standing on the emabnkment.
S' says the photons physically make contact with Albert's retinae in a particular order, one first, then the other; given what we know about how Albert's brain operates, to produce Albert's experiences, if the photons make physical contact with Albert's retinae in the order of one first, then the other, while Albert is physically standing on the embankment, then his brain will produce a non-simultaneous experience; from it's cosy position "in Albert's reference frame".
The only question to be answered is, do the photons make physical contact with Albert's retinae in the order of one first, then the other, while Albert is physically standing on the embankment?0 -
S' says the photons physically make contact with Albert's retinae in a particular order, one first, then the other;
Yes, we all agree with thatgiven what we know about how Albert's brain operates, to produce Albert's experiences, if the photons make physical contact with Albert's retinae in the order of one first, then the other, while Albert is physically standing on the embankment, then his brain will produce a non-simultaneous experience; from it's cosy position "in Albert's reference frame".
Yes, in S that is true. However, in your argument you are ignoring the effects of relativity in the processing that the brain has to do when viewed from the perspective of S'. Your statements are saying that everything up to the retina will change in S' compared to S, but once the electrical impulses start flowing from the retinas into the brain and are being processed that this will be the same in S' and S - that is not correct. You have to consistently apply the Lorenz transformation to everything, you can't pick and chose what's affected and what's not.But since the brain is an extended object, S' also says simultaneity in brain activity is not the same as in S. Hence, S' says the photons hit non-simultaneously, and S' says Albert experiences this as being simultaneously blinded in both eyes.
So both S and S' agree with what physically happens.
You can't treat the brain as a point object and everything that happens after the light hitting the retinas as a being instantaneous. The optic nerve is maybe 5cm in length, so even at the speed of light the fluctuations in the electric fields in the nerve will take 165 picoseconds to propagate, and then there's whatever other brain activity which may be located in physically separate parts of the brain requiring additional time for signals to pass, etc., plus then processing to compare the signals from each eye. All of this will experience relativistic effects, with the net effect that even though in S' the photons hit the retinas non-simultaneously, the experience for Albert in S' will be that they are simultaneous.
Effectively the scenario can be represented by the original mathematical representation such that at x=0 the light is experienced as simultaneous at t=1 in S, and simultaneous at t=y in S'. The retinas and brain processing are just adding some equal steps to each leg of the journey of the information about each photon getting to x=0.0 -
The question which then arises from that is, does the description of the events, as given by S', accurately correspond to the physical world?Yes, we all agree with that
In the physical world, Albert is physically located on the embankment; so, do the photons physically hit Albert's retinae non-simultaneously, while Albert is physically standing on the embankment; that is, while Albert is standing on the embankment, do the photons physically hit his retinae in the order of, for arguments sake, right first and then left?
It might be worth highlighting that I'm not saying that everything up to the retina will change in S', I'm simply asking if the events as described by S' correspond to the physical world; that is, do the photons physically hit Albert's retinae in the order of one first, then the other? Because, if they do, we can deduce how Albert's brain should process Albert's experience, based on how it processes other photons which physically hit his retinae, while he is standing on the embankment.Yes, in S that is true. However, in your argument you are ignoring the effects of relativity in the processing that the brain has to do when viewed from the perspective of S'. Your statements are saying that everything up to the retina will change in S' compared to S, but once the electrical impulses start flowing from the retinas into the brain and are being processed that this will be the same in S' and S - that is not correct. You have to consistently apply the Lorenz transformation to everything, you can't pick and chose what's affected and what's not.
Bear in mind, Albert's brain doesn't process Albert's experiences form the perspective of a relatively moving observer; Albert's brain doesn't apply the Lorentz transformation to its own neuronal activity; as far as Albert's brian is concerned, the length of time it take for signals from the retinae to reach the "processing centre" is the same for all photons which physically strike Albert's retinae, while Albert is standing on the embankment.
That is why we ask the question, do the events, as described by S' correspond to the physical world; do the photons physically strike Albert's retinae in the order of one first, then the other, while Albert is physically standing on the embankment?
We don't treat the brain as a point object, or at least I don't; we idealised the "processing centre" for the sake of argument; we also don't treat everything that happens after the light hitting the retinae as being instantaneous, we treat it how Albert's brian processes Albert's experiences.You can't treat the brain as a point object and everything that happens after the light hitting the retinas as a being instantaneous. The optic nerve is maybe 5cm in length, so even at the speed of light the fluctuations in the electric fields in the nerve will take 165 picoseconds to propagate, and then there's whatever other brain activity which may be located in physically separate parts of the brain requiring additional time for signals to pass, etc., plus then processing to compare the signals from each eye. All of this will experience relativistic effects, with the net effect that even though in S' the photons hit the retinas non-simultaneously, the experience for Albert in S' will be that they are simultaneous.
If Albert is standing on the embankment and two photons physically strike his retinae, right first and then the left; Albert's brain will process them in that order; the time it takes the signal from each retina to reach the "processing centre" will be the same for both eyes, such that, if the photons strike in the order of one first, then the other, Albert's experience will reflect this.
The issue is that we're not concerned with how a relatively moving observer will measure Albert's brain functions, and the conclusions he will draw about Albert's experiences.Effectively the scenario can be represented by the original mathematical representation such that at x=0 the light is experienced as simultaneous at t=1 in S, and simultaneous at t=y in S'. The retinas and brain processing are just adding some equal steps to each leg of the journey of the information about each photon getting to x=0.
We are interested in how Albert's brain processes sensory stimuli, to produce Albert's experiences; we know that when Albert's brain is producing Albert's experiences, it will process physical stimuli in the order they are received; that is, if two photons physically strike Albert's retinae, in the order of one first, then the other, then his brain will produce a non-simultaneous experience.
Knowing this we are only interested in the physicality of the events as described by S', and how they correspond to the physical world. S' says that the photons physically arrive at Albert's retinae in the order of one first, then the other, while Albert is physically standing on the embankment. If this is true, the Albert's brain will process the photons which physically strike his retinae, the same way it processes ALL photons which phyiscally strike his retinae, in the order they are received; because this is how Albert's brain produces Albert's experiences.
Some things that might be worth remembering ar that Albert's brain doesn't produce his experiences from the perspective of a relatively moving observer, and physical events don't happen "in" reference frames, because reference frames are constituted of mathematical co-ordinates which don't exist a priori in nature; reference frames are used to describe events which happen in the physical world, events don't happen "in" reference frames.0 -
I'm simply asking if the events as described by S' correspond to the physical world; that is, do the photons physically hit Albert's retinae in the order of one first, then the other?
The point is that there is no one definitive description of the sequence of events in "the physical world". The description of the events using S as the reference frame says the photons hit the retinas simultaneously and Albert experiences that as simultaneous, the description of events using S' as the reference frame says that the photons don't hit the retinas simultaneously but that Albert does still experience them simultaneously. Using the Lorenz transformations we can show that these descriptions are actually consistent with each other taking into account the relative velocity of the reference frames. Neither description is "more real" than the other, or than any other arbitrary reference frame.
The reference frames are more than arbitrary mathematical constructs. They are how reality and the sequence of events appear to an observer at rest with respect to that reference frame. If we start talking about a reference frame, we are implicitly talking about how events would be perceived by an observer in that reference frame - and that perception will be different for observers in other reference frames.
In our thought experiment there are two events where the photons hit each retina. An observer in S would describe them as simultaneous, an observer in S' would not. That is all. There are not four events - two simultaneous in S, and a different two non-simultaneous in S'. They are the same two physical real events, just experienced by different observers in S and S' as happening at different times.
As you say yourself:Bear in mind, Albert's brain doesn't process Albert's experiences form the perspective of a relatively moving observer;
Albert is in S and he experiences them as simultaneous.
Some other observer (Barry) is in S' and they would experience them as non-simultaneous.
Barry can use the Lorenz transformations to determine how the events would be experienced by an observer in S such as Albert, and would conclude that Albert would experience them as simultaneous.
Equally Albert can use the transformations to work out how the events would be experienced by an observer in S' such as Barry and would conclude that Barry would experience them as non-simultaneous.Albert's brain doesn't apply the Lorentz transformation to its own neuronal activity; as far as Albert's brian is concerned, the length of time it take for signals from the retinae to reach the "processing centre" is the same for all photons which physically strike Albert's retinae, while Albert is standing on the embankment.
Absolutely, and this is all about how things are percieved in S. The Lorenz transformations would only need to be applied to the neuronal activity etc. when Barry in S' is trying to work out how Albert in S would perceive the experiences.
Yes they do.That is why we ask the question, do the events, as described by S' correspond to the physical world;
The description of the timing of the photons hitting Albert's retinas depends on the relative motion of the observer doing the describing relative to Albert. An observer standing still beside Albert would agree with Albert that they hit simultaneously. An observer moving quickly relative to Albert would say they hit at different times. Albert still sees them as simultaneous.do the photons physically strike Albert's retinae in the order of one first, then the other, while Albert is physically standing on the embankment?
Yes, if that timing of the events is as described in Albert's frame of reference.If Albert is standing on the embankment and two photons physically strike his retinae, right first and then the left; Albert's brain will process them in that order;
Yes, again as described in Albert's frame of reference.the time it takes the signal from each retina to reach the "processing centre" will be the same for both eyes, such that, if the photons strike in the order of one first, then the other, Albert's experience will reflect this.
But that is exactly the point - the relatively moving observer describes the events happening differently to how Albert describes them, but can use the maths to find how Albert would describe them.The issue is that we're not concerned with how a relatively moving observer will measure Albert's brain functions, and the conclusions he will draw about Albert's experiences.
Yes, if that's how the sequence of the events is described in Albert's frame of reference.We are interested in how Albert's brain processes sensory stimuli, to produce Albert's experiences; we know that when Albert's brain is producing Albert's experiences, it will process physical stimuli in the order they are received; that is, if two photons physically strike Albert's retinae, in the order of one first, then the other, then his brain will produce a non-simultaneous experience.
Correct so far, and the events are still the same two physical events, just described in S' with different timings.Knowing this we are only interested in the physicality of the events as described by S', and how they correspond to the physical world. S' says that the photons physically arrive at Albert's retinae in the order of one first, then the other, while Albert is physically standing on the embankment.
But the point is that how you describe "the order that they are received" is totally dependent on the frame of reference that you are using, and since Albert's experiences are tied to his frame of reference, "the order that they are received" for Albert is simultaneous. It doesn't matter how the events would be described by any other relatively-moving observer, since that doesn't change the fact that for Albert the events happen simultaneously. You can't take the sequence of hitting one retina first and then the other retina as described in S' and use it directly as-is in S without applying the Lorenz transformations, and when you do, the events become simultaneous in S.If this is true, the Albert's brain will process the photons which physically strike his retinae, the same way it processes ALL photons which phyiscally strike his retinae, in the order they are received; because this is how Albert's brain produces Albert's experiences.
Exactly!Some things that might be worth remembering ar that Albert's brain doesn't produce his experiences from the perspective of a relatively moving observer,
That is true, they are all the same events, the reference frames just give us different perspectives on when they happen - but no one description is more right/valid than another.and physical events don't happen "in" reference frames, because reference frames are constituted of mathematical co-ordinates which don't exist a priori in nature; reference frames are used to describe events which happen in the physical world, events don't happen "in" reference frames.0 -
Again, thanks for the comprehensive reply ceejay.
I think it is necessary to clarify a couple of things which are central to the question. The first thing is, we are not interested in how a relatively moving observer will measure Albert's brain activity, and the conclusion he will draw about Albert's perception; we are interested in the physical process which leads to Albert's brain producing Albert's experiences or perception - we can extrapolate this to a more precise "machine' later, but for the time being we can stick with Albert.
The second point directly pertains to the following paragraph:The reference frames are more than arbitrary mathematical constructs. They are how reality and the sequence of events appear to an observer at rest with respect to that reference frame. If we start talking about a reference frame, we are implicitly talking about how events would be perceived by an observer in that reference frame - and that perception will be different for observers in other reference frames.
When we speak about reference frames, we are referring to the set of co-ordinate labels which are used to describe the events which occur in the physical world. The co-ordinate labels do not exist a priori in nature, so the reference frames that we refer to are mathematical constructs; that is, they are "mathematical things", not physical. These reference frames are used to describe the events which occur in the physical world and to describe how physical observers measure those events.
In that sense, we cannot really say that events occur "in" a reference frame, because that would be to ascribe physical properties to mathematical reference frames; more accurately we should say that the reference frames describe the physical events, or the events as described in, or by, the reference frames. This, I think, is part of the issue because it can cloud our reasoning if we aren't clear on it.
In a separate discussion on the same issue, a "proponent of Einsteinian relativity" - making the very same point that you are making in the response below - stated that "Albert isn't really an observer in Albert's reference frame", in the sense of Albert the physical person; when we say Albert in Albert's reference frame, we mean the co-ordinates which represent Albert in a given reference frame - this is an important distinction which we will discuss below.
Indeed, relativity says that the events described by any particular reference frame are not "more real" than those described by any other; the events described in every rerference frame are as real, and as physical, as those described in every other reference frame. This is what relativity says, but what we want to do is relate these descriptions of events back to the physical world.The point is that there is no one definitive description of the sequence of events in "the physical world". The description of the events using S as the reference frame says the photons hit the retinas simultaneously and Albert experiences that as simultaneous, the description of events using S' as the reference frame says that the photons don't hit the retinas simultaneously but that Albert does still experience them simultaneously. Using the Lorenz transformations we can show that these descriptions are actually consistent with each other taking into account the relative velocity of the reference frames. Neither description is "more real" than the other, or than any other arbitrary reference frame.
Albert's Brain
Let's start with what we know about how Albert's brain processes Albert's experiences; let's say that Albert is standing on the embankment, it's pitch black and his assistant hasn't arrived with his instruments yet, but someone is testing the lasers that will be used in the experiment; so we're not talking about the simultaneous/non-simultaneous events just yet.
Standing on the embankment, Albert sees two flashes of light, but they don't seem to flash together; Albert sees the one from the right first, and then the one from the left - this must be because the tester has fired them in this order, although that is not necessarily relevant for this line of reasoning.
We know that Albert sees the one from the right first and then the one from the left; we are interested in why this is. Knowing how Albert's brain operates, when producing Albert's perceptions, we can deduce that the reason he sees the right flash first and then the left, is because the photons from the right laser must have physically hit his right retina first and the photon from the left laser must have physically hit his left retina second; such that the order of the physical contact between the photons and Albert's retinae must have been right first and left second. The time difference between them doesn't matter here, we are only interested in the order.
This means that Albert's brain processes photons which physically strike his retinae, in the order in which they make physical contact wth the retina, or cornea, or, for simplicity sake, eye.
This is how Albert's brain will process ALL photons which physically make contact with his eyes; namely, in the order they are received. From here, we are only interested in the order in which the photons make physical contact with Albert's eyes and the physicality of any descriptions which describe the order in which the photons hit Albert's eyes - because we know that Albert's brain will process ALL photons in the order they are received, to give Albert the consequentially ordered perception.
Here we come across the issue that was alluded to above, the issue of saying that physical observers are "in" mathematical reference frames. If we say that "Albert is in S", then by extension Albert's retinae are in S, such that, any event which occurs on the surface of Albert's retinae must necessarily occur in S, or "in Albert's reference frame"; so, if S' says that the photons physically strike Albert's retinae non-simultaneously, they must necessarily strike them non-simultaneously "in Albert's reference frame" or in S.In our thought experiment there are two events where the photons hit each retina. An observer in S would describe them as simultaneous, an observer in S' would not. That is all. There are not four events - two simultaneous in S, and a different two non-simultaneous in S'. They are the same two physical real events, just experienced by different observers in S and S' as happening at different times.
As you say yourself:
Albert is in S and he experiences them as simultaneous.
Some other observer (Barry) is in S' and they would experience them as non-simultaneous.
Barry can use the Lorenz transformations to determine how the events would be experienced by an observer in S such as Albert, and would conclude that Albert would experience them as simultaneous.
Equally Albert can use the transformations to work out how the events would be experienced by an observer in S' such as Barry and would conclude that Barry would experience them as non-simultaneous.
But we know that that is not what relativity says, so there must be an issue with our statement "Albert is in S"; the issue is addressed when we acknowledge that Albert isn't "in" S, and the photons don't strike his retinae "in" S, but that S is a mathematical representation of the events which occur in the physical world. Similarly, S' is a mathematical representation of the measurements of a relatively moving observer. This just brings us back to the question of how the relatively moving observer's measurements correspond to the physical world and the physical events. Do the photons physically strike Albert's retinae non-simultaneously? Because if they do, we know how Albert's brain will process them to create Albert's experience, in the physical world, on the embankment. Again, we are not interested in how a relatively moving observer will, supposedly, measure Albert's brain activity, and the conlcusion he will, supposedly, arrive at, with respect to Albert's experiences - we are interested in Albert's experiences, not the relatively moving observers; here the physicality of the non-simultaneous retinae striking events is key.
How things are perceived by Albert "in" S depends on how his brain processes physical stimuli which make physical contact with his retinae; we know that his brain processes photons in the order in which they make physical contact with his retinae.Absolutely, and this is all about how things are percieved in S. The Lorenz transformations would only need to be applied to the neuronal activity etc. when Barry in S' is trying to work out how Albert in S would perceive the experiences.
We are not interested in how Barry, supposedly, measures Albert's brain activity and what his, supposed, perception of Albert's experience will be.
If they correspond to the physical world, then it means that photons physically strike Albert's retinae in the order of one first then the other, while Albert is standing on the embankment. If this is true, then Albert's brain will process them in that order and produce a non-simultaneous perception.Yes they do [correspond to the physical world].
The question we are interested in is, is the description of events, as described by the relatively moving observer accurate, and do they correspond to the physical world; that is, the relatively moving observer says that, while Albert is standing on the embankment, photons make physical contact with his retinae in the order of one first, then the other; we want to know whether or not the photons do make physical contact with Albert's retinae, in the order of one first, then the other, while Albert is standing on the embankment; because if they do, then this is how Albert's brain will process them, and the perception or experience it produces will be a non-simultaneous one.The description of the timing of the photons hitting Albert's retinas depends on the relative motion of the observer doing the describing relative to Albert. An observer standing still beside Albert would agree with Albert that they hit simultaneously. An observer moving quickly relative to Albert would say they hit at different times. Albert still sees them as simultaneous.
Albert's brain operates in the physical world; it will process physical photons which physically strike his retinae in the order they are received, while he is standing on the embankment. If reference frames don't reflect this fact, then they do not describe the physical world.Yes, if that timing of the events is as described in Albert's frame of reference.
Yes, if that's how the sequence of the events is described in Albert's frame of reference.
Again, this is how Albert's brain will process Albert's experiences, while Albert is physically standing on the embankment; we are not interested in how Barry will, supposedly, measure Albert's brain activity, or what Barry's, supposed, perception of Albert's experience will be.Yes, again as described in Albert's frame of reference.
We are just interested in the physicality of the events as described by the relatively moving observer; 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? If they do, we know how Albert's brain processes ALL photons which make physical contact with his retinae in the order of one first then the other.But that is exactly the point - the relatively moving observer describes the events happening differently to how Albert describes them, but can use the maths to find how Albert would describe them.
Indeed, this is the idea; as described by S', the photons, supposedly, make physical contact with Albert's retinae in the order of one first then the other; if this is true, then this is how Albert's brain will process them to produce Albert's experience; because Albert's brain processes ALL photons, which make physical contact with his eyes, in the order they are received.Correct so far, and the events are still the same two physical events, just described in S' with different timings.
Albert's experiences aren't tied to any mathematical description of physical events; Albert's brian operates in the physical world and it will process ALL photons, which physically strike his eyes, in the order they are received.But the point is that how you describe "the order that they are received" is totally dependent on the frame of reference that you are using, and since Albert's experiences are tied to his frame of reference, "the order that they are received" for Albert is simultaneous. It doesn't matter how the events would be described by any other relatively-moving observer, since that doesn't change the fact that for Albert the events happen simultaneously. You can't take the sequence of hitting one retina first and then the other retina as described in S' and use it directly as-is in S without applying the Lorenz transformations, and when you do, the events become simultaneous in S.
Again, we are interested in the physicality of the events described by the reference frames; we want to know if 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 they do, then Albert's brain will process them in that order.
Indeed, no one is more valid than the other, all are, supposedly, equally physical. If the events as described by S' are physical, then it means that photons physically strike Albert's retinae in the order of one first then the other; if this is true, then Albert's retinae will process them in that order, and produce a non-simultaneous experience.That is true, they are all the same events, the reference frames just give us different perspectives on when they happen - but no one description is more right/valid than another.0 -
Apologies, I forgot to reply to this post.
We don't need to reference any reference frames initially, we can just establish how Albert's brain processes physical stimuli. We know that, while Albert is physically standing on the embankment, his brain will process all photons, which physically strike his retinae, in the order they are received; that is, if photons physically strike his retinae in the order of one first then the other, while he is standing on the embankment, his brian will process them in that order.Yes we are talking about S and S'. What is and isn't "simultaneous" depends on what reference frame you are using.
From there we are only interested in the physicality of events as described by the different reference frames. S' says that, while Albert is physically standing on the embankment, two photons physically strike his retinae in the order of one first then the other; if this is true, then knowing how Albert's brain processes photons which physically strike his retinae, his brain should produce an experience of light flashing in the order of one side first, then the other.
I'm referring to the physical world; if photons physically strike your retinae in the order of one first then the other, while you are standing in your front garden, at rest relative to the garden, will your brain process them in that order?Which reference frame are you referring to?
If the strikes are simultaneous, as defined by S, then my brain will produce a "simultaneous" experience. The same is not true for simultaneous strikes as defined by S', however.
Bearing in mind that the order of events doesn't depend on how they are described by mathematical reference frames. The mathematical reference frames can help us deduce how one observer will, supposedly, measure the events, given the co-ordinates of the events in another reference frame.
We are then interested in how these descriptions relate back to the physical world; that is, if, according to S', the photons strike Albert's retinae in the order of one first then the other, while he is standing on the embankment, do they physically strike his retinae in the order of one first then the other?
If they do, then we know how Albert's brain processes photons which physically strike his retinae in the order of one first, then the other, while he is standing on the embankment.0 -
I don't think any one here is debating whether the order in which information is received, is the order in which it is processed.
So you only want to know how one observer in one reference frame will determine physical observations? In this case; our lovely test subject Albert sitting on an embankment. Well we have clarified many times that he will determine processes to occur in the order he receives them, no?Again, thanks for the comprehensive reply ceejay.
I think it is necessary to clarify a couple of things which are central to the question. The first thing is, we are not interested in how a relatively moving observer will measure Albert's brain activity, and the conclusion he will draw about Albert's perception; we are interested in the physical process which leads to Albert's brain producing Albert's experiences or perception - we can extrapolate this to a more precise "machine' later, but for the time being we can stick with Albert.
That is to say he doesn't perceive things "backwards" in a sense that, a plate is broken on the ground, recombines and the then flies back up to the top of a table, is considered "backwards" as that's not how the event actually happened. He actually received the information as the plate falling, breaking and lying in pieces.
Next thing to add on is that, if he receives two pieces of information at the same time, he perceives these things to happen at the same time, no? But this does not mean that he is correct. Events can be spatially or temporally separated. For example he might receive the information of a star going supernova and a green light signal at the same time and consider that they both "physically" happened at the same time. But the star went supernova millions of years ago, it just took the light that long to get to him.
When we speak about reference frames, we are referring to the set of co-ordinate labels which are used to describe the events which occur in the physical world. The co-ordinate labels do not exist a priori in nature, so the reference frames that we refer to are mathematical constructs; that is, they are "mathematical things", not physical. These reference frames are used to describe the events which occur in the physical world and to describe how physical observers measure those events.
Well no I think we need to lend a bit more physical structure to reference frames in the that they are real. True, yes the labels we use are arbitrary and only mathematical concepts physicists use to make their problems easier and therefore don't exist in nature. But the actual reference frame itself, where "things can happen" do exist in nature. I mean trains, planes, boats, cars and spaceships are real in nature and are designed to "exist" in different reference frames then the earth in order to allow faster movement between the arbitrary points on the earth's surface that we use to describe location. The points aren't real, but the reference frames are there. Unless you are denying the fact that we exist etc but I don't think we need to debate existence at this point.
Well no they don't occur in the arbitrary points (x,y,z,t) that we use to "locate" the reference frame. But they do occur in physical parts where the experiment, whatever happened.In that sense, we cannot really say that events occur "in" a reference frame, because that would be to ascribe physical properties to mathematical reference frames; more accurately we should say that the reference frames describe the physical events, or the events as described in, or by, the reference frames. This, I think, is part of the issue because it can cloud our reasoning if we aren't clear on it.
No one is denying here that, the mathematical reference part is just an address given to something, so that it can be used to gain data from, pretty much.
Sure, ok.In a separate discussion on the same issue, a "proponent of Einsteinian relativity" - making the very same point that you are making in the response below - stated that "Albert isn't really an observer in Albert's reference frame", in the sense of Albert the physical person; when we say Albert in Albert's reference frame, we mean the co-ordinates which represent Albert in a given reference frame - this is an important distinction which we will discuss below.
Well if there are real, they must be physical? They might contradict each other, but they are still physical. I mean how can a radio in the same reference frame be loud and quiet?Indeed, relativity says that the events described by any particular reference frame are not "more real" than those described by any other; the events described in every rerference frame are as real, and as physical, as those described in every other reference frame. This is what relativity says, but what we want to do is relate these descriptions of events back to the physical world.
Ok, you can mess around with your thought experiment as much as you like, as long as you give us the same freedom.Albert's Brain
Let's start with what we know about how Albert's brain processes Albert's experiences; let's say that Albert is standing on the embankment, it's pitch black and his assistant hasn't arrived with his instruments yet, but someone is testing the lasers that will be used in the experiment; so we're not talking about the simultaneous/non-simultaneous events just yet.
So what can we deduce straight away from this? Not just necessarily that they were fired at different times.Standing on the embankment, Albert sees two flashes of light, but they don't seem to flash together; Albert sees the one from the right first, and then the one from the left - this must be because the tester has fired them in this order, although that is not necessarily relevant for this line of reasoning.
1) as you say the hatch on laser A was opened first and then the hatch on laser B was opened.
2) the hatch on both lasers was opened at the same time. Laser A is just closer then laser B.
3) the light from laser A is faster then the light from B.
Now we can throw away 3 straight away as every modern day physics theory is based on the speed on light being constant.
Again as you said, its dark so Albert doesn't know which of one or two is different. We can specify in the experiment which is the case.
Because, like I said earlier, either situation 1 or 2 is set up. And like we have all said earlier, Albert's brain perceives information in the order it is received. I don't know why you keep bringing this point up since no one is debating it?We know that Albert sees the one from the right first and then the one from the left; we are interested in why this is. Knowing how Albert's brain operates, when producing Albert's perceptions, we can deduce that the reason he sees the right flash first and then the left, is because the photons from the right laser must have physically hit his right retina first and the photon from the left laser must have physically hit his left retina second; such that the order of the physical contact between the photons and Albert's retinae must have been right first and left second. The time difference between them doesn't matter here, we are only interested in the order.
Why do we not care about the time of the events? Order depends on the timing of the events,no? Depending on the timing they could be simultaneous, or not.
So can we now make this a postulate of your argument and assume it is now true in all cases?This means that Albert's brain processes photons which physically strike his retinae, in the order in which they make physical contact wth the retina, or cornea, or, for simplicity sake, eye.
But order depends on (x,t), so it is not as simple as you say.This is how Albert's brain will process ALL photons which physically make contact with his eyes; namely, in the order they are received. From here, we are only interested in the order in which the photons make physical contact with Albert's eyes and the physicality of any descriptions which describe the order in which the photons hit Albert's eyes - because we know that Albert's brain will process ALL photons in the order they are received, to give Albert the consequentially ordered perception.
See, this is where you lose me. Up until you say "so, if S' says that the photons physically" is fairly self evident. But I have no idea what you mean after, where you get you argument and logic from.Here we come across the issue that was alluded to above, the issue of saying that physical observers are "in" mathematical reference frames. If we say that "Albert is in S", then by extension Albert's retinae are in S, such that, any event which occurs on the surface of Albert's retinae must necessarily occur in S, or "in Albert's reference frame"; so, if S' says that the photons physically strike Albert's retinae non-simultaneously, they must necessarily strike them non-simultaneously "in Albert's reference frame" or in S.
How do you draw the conclusion that what S' perceives is what S should perceive? You said it yourself "If we say that "Albert is in S", then by extension Albert's retinae are in S, such that, any event which occurs on the surface of Albert's retinae must necessarily occur in S, or "in Albert's reference frame"
This basically means we are obliged to use the same coordinate system for all of S. We also have to use a different coordinate system for S'. This for me is a pretty big problem and one you should look to address and make self consistent. Or in the very least explain it in a better, easier to understand way, as simply as possible.
The only issue so far that we have encountered is your comments in the previous.But we know that that is not what relativity says, so there must be an issue with our statement "Albert is in S"; the issue is addressed when we acknowledge that Albert isn't "in" S, and the photons don't strike his retinae "in" S, but that S is a mathematical representation of the events which occur in the physical world. Similarly, S' is a mathematical representation of the measurements of a relatively moving observer. This just brings us back to the question of how the relatively moving observer's measurements correspond to the physical world and the physical events. Do the photons physically strike Albert's retinae non-simultaneously? Because if they do, we know how Albert's brain will process them to create Albert's experience, in the physical world, on the embankment. Again, we are not interested in how a relatively moving observer will, supposedly, measure Albert's brain activity, and the conlcusion he will, supposedly, arrive at, with respect to Albert's experiences - we are interested in Albert's experiences, not the relatively moving observers; here the physicality of the non-simultaneous retinae striking events is key.
The issue isn't addressed when we say Albert isn't "in" S. He might as well be. He's on an embankment on the earth. Earth can be moving at any arbitrary speed, but we might as well say its not moving, because we'll have to "add" its initial speed onto the relatively moving observer.
We use the tags S and S' to show that they are in different frames. The photons physically hit his eyes on the earth. This is described by S. The photons then have to travel to S', in order to be observed by the relatively moving observer. Due to the motion of S' the light will be received differently then how it was received in S. But like you said we don't care about how S' observed the light.
Your postulate again
How things are perceived by Albert "in" S depends on how his brain processes physical stimuli which make physical contact with his retinae; we know that his brain processes photons in the order in which they make physical contact with his retinae.
Ok, but, why are we sometimes interested?We are not interested in how Barry, supposedly, measures Albert's brain activity and what his, supposed, perception of Albert's experience will be.
Your postulate.
If they correspond to the physical world, then it means that photons physically strike Albert's retinae in the order of one first then the other, while Albert is standing on the embankment. If this is true, then Albert's brain will process them in that order and produce a non-simultaneous perception.
So now we are interested in S' again? It is accurate and does correspond to the physical world.The question we are interested in is, is the description of events, as described by the relatively moving observer accurate, and do they correspond to the physical world; that is, the relatively moving observer says that, while Albert is standing on the embankment, photons make physical contact with his retinae in the order of one first, then the other; we want to know whether or not the photons do make physical contact with Albert's retinae, in the order of one first, then the other, while Albert is standing on the embankment; because if they do, then this is how Albert's brain will process them, and the perception or experience it produces will be a non-simultaneous one.
So does mine, and it also follows your postuale.Albert's brain operates in the physical world; it will process physical photons which physically strike his retinae in the order they are received, while he is standing on the embankment. If reference frames don't reflect this fact, then they do not describe the physical world.
So now we are not interested in S'?Again, this is how Albert's brain will process Albert's experiences, while Albert is physically standing on the embankment; we are not interested in how Barry will, supposedly, measure Albert's brain activity, or what Barry's, supposed, perception of Albert's experience will be.
Yup your postulate seems to be true.We are just interested in the physicality of the events as described by the relatively moving observer; 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? If they do, we know how Albert's brain processes ALL photons which make physical contact with his retinae in the order of one first then the other.
So now we are interested in S' again? You've got to remember that for S' the light hits Albert and then gets detected by S'. It has a longer path to take then in S. Albert gets hit in the reference frame, as described mathematically by S.Indeed, this is the idea; as described by S', the photons, supposedly, make physical contact with Albert's retinae in the order of one first then the other; if this is true, then this is how Albert's brain will process them to produce Albert's experience; because Albert's brain processes ALL photons, which make physical contact with his eyes, in the order they are received.
No they are described by them. Language is no way tied to the letters that are used to describe it, yet you don't seem to be debating it.Albert's experiences aren't tied to any mathematical description of physical events; Albert's brian operates in the physical world and it will process ALL photons, which physically strike his eyes, in the order they are received.
So you want to test your postulate?Again, we are interested in the physicality of the events described by the reference frames; we want to know if 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 they do, then Albert's brain will process them in that order.Indeed, no one is more valid than the other, all are, supposedly, equally physical. If the events as described by S' are physical, then it means that photons physically strike Albert's retinae in the order of one first then the other; if this is true, then Albert's retinae will process them in that order, and produce a non-simultaneous experience.
So what you are saying does the moon, which is moving relative to the earth affect, my measurement, on earth? Since the moon measures an event that was simultaneous on earth not simultaneous due to its relative motion?
I would take exception to the line "If the events as described by S' are physical, then it means that photons physically strike Albert's retinae in the order of one first then the other; if this is true, then Albert's retinae will process them in that order, and produce a non-simultaneous experience."
How did you deduce this? Well not deduce, how did you put these two together and get 4? Please try and explain this to me0 -
That's great. The important point then is photons physically making contact with the retinae of an observer constitutes "receiving information".citrus burst wrote: »I don't think any one here is debating whether the order in which information is received, is the order in which it is processed.
On the basis of seeing both lights at the same time, and no other information, if Albert concludes anything more than that he saw the lights at the same time, then he is potentially setting himself up to be incorrect. What he can conclude is that photons from both events struck his retinae at the same time, and this is why his brain processed the flahses as occurring together.citrus burst wrote: »So you only want to know how one observer in one reference frame will determine physical observations? In this case; our lovely test subject Albert sitting on an embankment. Well we have clarified many times that he will determine processes to occur in the order he receives them, no?
That is to say he doesn't perceive things "backwards" in a sense that, a plate is broken on the ground, recombines and the then flies back up to the top of a table, is considered "backwards" as that's not how the event actually happened. He actually received the information as the plate falling, breaking and lying in pieces.
Next thing to add on is that, if he receives two pieces of information at the same time, he perceives these things to happen at the same time, no? But this does not mean that he is correct. Events can be spatially or temporally separated. For example he might receive the information of a star going supernova and a green light signal at the same time and consider that they both "physically" happened at the same time. But the star went supernova millions of years ago, it just took the light that long to get to him.
The breaking plate example is somewhat different to the question we are considering, but it isn't one that is disputed.
We don't need to lend more physical structure to the mathematical co-ordinates, I think that is part of the underlying issue. We can treat the mathematical co-ordinate systems as they are, a means of describing what occurs in those physical reference frames you mention, the car, the boat, the spaceship etc. It can cloud our reasoning if we don't make this distinction, because we start to make statements such as "it occurs in this reference frame but not in that"; this is made clearer when we talk about photons making physical contact with the retinae of an observer. If we say they make physical contact in a certain order in one reference frame, but not in the other, then we are suggesting that an observers retinae can be both in a reference frame and not in a reference frame.citrus burst wrote: »Well no I think we need to lend a bit more physical structure to reference frames in the that they are real. True, yes the labels we use are arbitrary and only mathematical concepts physicists use to make their problems easier and therefore don't exist in nature. But the actual reference frame itself, where "things can happen" do exist in nature. I mean trains, planes, boats, cars and spaceships are real in nature and are designed to "exist" in different reference frames then the earth in order to allow faster movement between the arbitrary points on the earth's surface that we use to describe location. The points aren't real, but the reference frames are there. Unless you are denying the fact that we exist etc but I don't think we need to debate existence at this point.
When we make explicit reference to the physical location of the observer we can avoid this conflation. When we say that one reference frame describes the physical events in such a way that it says the photons make physical contact with the observers retinae, in the order of one first then the other, while he is standing on the embankment, then we can make deductions based on what we know about how an observers brain will process photons which physically strike the observers retinae i.e. in the order that they physically hit the retinae.
Indeed, S' says that, while Albert is physically standing on the embankment, photons physically strike his retinae in the order of one first, then the other. Given our postulate, we know how Albert's brain should process any photons, which make physical contact with his retinae, to produce his experience, while he is standing on the embankmentcitrus burst wrote: »Well no they don't occur in the arbitrary points (x,y,z,t) that we use to "locate" the reference frame. But they do occur in physical parts where the experiment, whatever happened.
No one is denying here that, the mathematical reference part is just an address given to something, so that it can be used to gain data from, pretty much.
If the events as described by S' are real, physical, valid, or however we wish to describe them; if they correspond to the physical world, then it means that photons physically strike Albert's retinae in the order of one first, then the other, while he is physically standing on the embankment. If this is true, given our postulate, we know how Albert should process photons which physically strike his retinae, while he is standing on the emabnkment.citrus burst wrote: »Well if there are real, they must be physical? They might contradict each other, but they are still physical. I mean how can a radio in the same reference frame be loud and quiet?
We mess around with the thought experiment solely to establish the postulate to which you have agreed. But, of course, the same freedom must be extended.citrus burst wrote: »Ok, you can mess around with your thought experiment as much as you like, as long as you give us the same freedom.
What we can also deduce, and which is the important point for the issue in question, is that the photons from one laser physically struck his retinae in the order of A first, then then B.citrus burst wrote: »So what can we deduce straight away from this? Not just necessarily that they were fired at different times.
1) as you say the hatch on laser A was opened first and then the hatch on laser B was opened.
2) the hatch on both lasers was opened at the same time. Laser A is just closer then laser B.
3) the light from laser A is faster then the light from B.
Now we can throw away 3 straight away as every modern day physics theory is based on the speed on light being constant.
Again as you said, its dark so Albert doesn't know which of one or two is different. We can specify in the experiment which is the case.
We're not interested in the timing because there are a near infinite range of time values which can result in a given order of events, we are only interested in the order in which the photons make physical contact with Albert's retinae, because we know that is how his brain will process them.citrus burst wrote: »Because, like I said earlier, either situation 1 or 2 is set up. And like we have all said earlier, Albert's brain perceives information in the order it is received. I don't know why you keep bringing this point up since no one is debating it?
Why do we not care about the time of the events? Order depends on the timing of the events,no? Depending on the timing they could be simultaneous, or not.
True for all photons which make physical contact with an observers retinae?citrus burst wrote: »So can we now make this a postulate of your argument and assume it is now true in all cases?
I would be more inclined to say that (x,t) depend on the order; that is, I would ascribe the causal influence to the physical events, not the mathematical co-ordinates.citrus burst wrote: »But order depends on (x,t), so it is not as simple as you say.
The logic is quite simple. We have the agreed postulate which tells us how Albert's brain will process all photons which make physical contact with Albert's retinae, while Albert is physically standing on the embankment; that is, in the order they make phyiscal contact with his retinae.citrus burst wrote: »See, this is where you lose me. Up until you say "so, if S' says that the photons physically" is fairly self evident. But I have no idea what you mean after, where you get you argument and logic from.
How do you draw the conclusion that what S' perceives is what S should perceive?
S' says that the photons make physical contact with Albert's retinae, in the order of one first, then the other, while Albert is physically standing on the embankment. If this is valid, then Albert's brain should process them in that order, given the agreed upon postulate.
This is just highlighting the issue of making such statements as "the photons strike Albert's retinae simultaneously 'in Albert's reference frame'" or "the photons strike Albert's retinae non-simultaneously 'not in Albert's reference frame'".citrus burst wrote: »You said it yourself "If we say that "Albert is in S", then by extension Albert's retinae are in S, such that, any event which occurs on the surface of Albert's retinae must necessarily occur in S, or "in Albert's reference frame"
This basically means we are obliged to use the same coordinate system for all of S. We also have to use a different coordinate system for S'. This for me is a pretty big problem and one you should look to address and make self consistent. Or in the very least explain it in a better, easier to understand way, as simply as possible.
If Albert is in Albert's reference frame, then so are his retinae; if photons physically strike his retinae then they necessarily strike them "in Albert's reference frame". So if S' says they strike Albert's retinae non-simultaneously, then they must, necessarily, strike Albert's retinae non-simultnaeously "in Albert's reference frame" if Albert and his retinae are "in Albert's reference frame".
We can avoid this issue by simply acknowledging the mathematical reference frames for what they are; attempted descriptions of physical events.
We can say that S' says that that the photons physically strike Albert's retinae in the order of one first, then the other, while Albert is physically located on the embankment. We can say that this is what a relatively moving observer will, supposedly, measure. We can then relate these back to the physical world. Given our postulate, we know how Albert's brain will process photons which physically make contact with his retinae, while he is standing on the embankment. If the description of events, as given by S', correspond to physical events, then Albert's brain should process them as a non-simultaneous event. In other words, if the relatively moving observers measurements, of the photons which physically strike Albert's retinae, accurately correspond to physical events i.e. if the photons do physically strike Albert's retinae in the order of one first, then the other, while he is physically standing on the embankment, then we know how his brain should process them, to form Albert's experience.
We don't care about how the observer on the train will observe the light, we are interested in what the observer on the train says about how the photons will physically strike Albert's retinae, while Albert is standing on the embankment. Does his description of events correspond to the physical world? He says that the photons physically strike Albert's retinae in the order of one first, then the other, while Albert is standing on the embankment. If the photons physically strike Albert's retinae in the order of one first, then the other, while he is standing on the embankment, then given our postulate, his brain will process an experience where light flashes from one direction first, then the other.citrus burst wrote: »The only issue so far that we have encountered is your comments in the previous.
The issue isn't addressed when we say Albert isn't "in" S. He might as well be. He's on an embankment on the earth. Earth can be moving at any arbitrary speed, but we might as well say its not moving, because we'll have to "add" its initial speed onto the relatively moving observer.
We use the tags S and S' to show that they are in different frames. The photons physically hit his eyes on the earth. This is described by S. The photons then have to travel to S', in order to be observed by the relatively moving observer. Due to the motion of S' the light will be received differently then how it was received in S. But like you said we don't care about how S' observed the light.
We are interested in how S' corresponds to the physical; that is, the physicality of the photon striking events, because we know how Albert's brain will process photons which physically strike his retinae.citrus burst wrote: »Ok, but, why are we sometimes interested?
...
So now we are interested in S' again? It is accurate and does correspond to the physical world.
...
So now we are not interested in S'?
Sorry, I'm not sure what you mean by "so does mine", do you mean, "so does my brain [process photons in the order they are received]?citrus burst wrote: »So does mine, and it also follows your postuale.
Yes, but S' says that Albert's retinae get struck in the order of one first then the other; if this is physically accurate, then Albert's brain will process them in that order.citrus burst wrote: »So now we are interested in S' again? You've got to remember that for S' the light hits Albert and then gets detected by S'. It has a longer path to take then in S. Albert gets hit in the reference frame, as described mathematically by S.
We could debate the issue of language, but I don't think we need to; we can stick to talking about reference frames and how they correspond to the physical world.citrus burst wrote: »No they are described by them. Language is no way tied to the letters that are used to describe it, yet you don't seem to be debating it.
We are interested in how your brain processes your experiences, and what affects your experiences is how sensory information is taken in by your sensory organs; for example, how photons physically strike your retinae. If an observer on the moon says that photons physically strike your retinae in the order of one first, then the other, then this will have direct consequences for how your brain processes those photons; assuming the measurements of the observer on the moon correspond to physical events; that is, if he says photons physically strike your retinae in the order of one first then the other, while you are standing in your front garden, and if his measurement accurtely reflect the physical world, then your brain should process the photons in that order, to produce your experience.citrus burst wrote: »So what you are saying does the moon, which is moving relative to the earth affect, my measurement, on earth? Since the moon measures an event that was simultaneous on earth not simultaneous due to its relative motion?
We start with our postulate, which tells us how Albert's brain processes photons which physically strike his retinae, while he is standing on the embankment.citrus burst wrote: »I would take exception to the line "If the events as described by S' are physical, then it means that photons physically strike Albert's retinae in the order of one first then the other; if this is true, then Albert's retinae will process them in that order, and produce a non-simultaneous experience."
How did you deduce this? Well not deduce, how did you put these two together and get 4? Please try and explain this to me
S' says that the photons physically strike his retinae in the order of one first, then the other, while he is standing on the embankment.
If the events, as described by S', correspond to the physical world; that is, if photons strike Albert's retinae in the order of one first, then the other, while he is standing on the embankment, then given our postulate, Albert's brain should process them in the order of one first, then the other, and produce an ordered experience.0 -
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So lets get some common ground. S says that the two photons hit Albert's eyes simultaneous? Albert's memories reflect this as per the postulate?
S' is moving relative to S?
S' detects one photon before the other, after they have reflected off Albert's eyes?
Somehow Albert's memories are affected by this?
I would like to add in another observer in Albert's frame, or as you like, standing next to Albert. Or at least, have Albert observing something.
This was just to show that we can trust Albert's memory.
The breaking plate example is somewhat different to the question we are considering, but it isn't one that is disputed.
Well we need to make the distinction that some things are moving relative to other things. We can do it whatever we're comfortable with.We don't need to lend more physical structure to the mathematical co-ordinates, I think that is part of the underlying issue. We can treat the mathematical co-ordinate systems as they are, a means of describing what occurs in those physical reference frames you mention, the car, the boat, the spaceship etc. It can cloud our reasoning if we don't make this distinction, because we start to make statements such as "it occurs in this reference frame but not in that"; this is made clearer when we talk about photons making physical contact with the retinae of an observer. If we say they make physical contact in a certain order in one reference frame, but not in the other, then we are suggesting that an observers retinae can be both in a reference frame and not in a reference frame.
I assume the photons make contact with some sort of detector, can be detected by all all observers etc.If we say they make physical contact in a certain order in one reference frame, but not in the other, then we are suggesting that an observers retinae can be both in a reference frame and not in a reference frame.
Sorry can you clarify what you mean by this?
And treat their observations correctly.When we make explicit reference to the physical location of the observer we can avoid this conflation. When we say that one reference frame describes the physical events in such a way that it says the photons make physical contact with the observers retinae, in the order of one first then the other, while he is standing on the embankment, then we can make deductions based on what we know about how an observers brain will process photons which physically strike the observers retinae i.e. in the order that they physically hit the retinae.
S also says he is standing on the embankment. But S says that they "physically" strike his retinas simultaneous.Indeed, S' says that, while Albert is physically standing on the embankment, photons physically strike his retinae in the order of one first, then the other. Given our postulate, we know how Albert's brain should process any photons, which make physical contact with his retinae, to produce his experience, while he is standing on the embankment
But this leads nothing to your argument.If the events as described by S' are real, physical, valid, or however we wish to describe them; if they correspond to the physical world, then it means that photons physically strike Albert's retinae in the order of one first, then the other, while he is physically standing on the embankment. If this is true, given our postulate, we know how Albert should process photons which physically strike his retinae, while he is standing on the emabnkment.
No they physically struck each other at the same time.What we can also deduce, and which is the important point for the issue in question, is that the photons from one laser physically struck his retinae in the order of A first, then then B.
Fair enoughWe're not interested in the timing because there are a near infinite range of time values which can result in a given order of events, we are only interested in the order in which the photons make physical contact with Albert's retinae, because we know that is how his brain will process them.
Yes, I guess.True for all photons which make physical contact with an observers retinae?
But as we are debating, order is relative to velocity.I would be more inclined to say that (x,t) depend on the order; that is, I would ascribe the causal influence to the physical events, not the mathematical co-ordinates.
At this point, I'm just going to stop and throw in another postulate. Albert's brain stops detecting photons after they are detected. This ok?The logic is quite simple. We have the agreed postulate which tells us how Albert's brain will process all photons which make physical contact with Albert's retinae, while Albert is physically standing on the embankment; that is, in the order they make phyiscal contact with his retinae.
As in it only detects a photon once.
So in this case. Laser fired, hits Albert's eye, detected, some is reflected and detected by S'.
Yes but if we use are new postulate, Albert's brain stop detecting the photons before they reached S'.S' says that the photons make physical contact with Albert's retinae, in the order of one first, then the other, while Albert is physically standing on the embankment. If this is valid, then Albert's brain should process them in that order, given the agreed upon postulate.
Ok
This is just highlighting the issue of making such statements as "the photons strike Albert's retinae simultaneously 'in Albert's reference frame'" or "the photons strike Albert's retinae non-simultaneously 'not in Albert's reference frame'".
No they are detected none simultaneous.If Albert is in Albert's reference frame, then so are his retinae; if photons physically strike his retinae then they necessarily strike them "in Albert's reference frame". So if S' says they strike Albert's retinae non-simultaneously, then they must, necessarily, strike Albert's retinae non-simultnaeously "in Albert's reference frame" if Albert and his retinae are "in Albert's reference frame".
Or we could avoid this issue, by only using mathematical reference frames. You assume the problem arises from the use of them, after reading "physically strike Albert's retinae in the order of one first" 30+ times in one post it gets a bit tiresome and we can be forgiven for taking short cuts like using S instead of "Albert's rest frame"We can avoid this issue by simply acknowledging the mathematical reference frames for what they are; attempted descriptions of physical events.
But if we use postulate 2, Albert's brain stopped detecting the photons after they hit his eye.We can say that S' says that that the photons physically strike Albert's retinae in the order of one first, then the other, while Albert is physically located on the embankment. We can say that this is what a relatively moving observer will, supposedly, measure. We can then relate these back to the physical world. Given our postulate, we know how Albert's brain will process photons which physically make contact with his retinae, while he is standing on the embankment. If the description of events, as given by S', correspond to physical events, then Albert's brain should process them as a non-simultaneous event. In other words, if the relatively moving observers measurements, of the photons which physically strike Albert's retinae, accurately correspond to physical events i.e. if the photons do physically strike Albert's retinae in the order of one first, then the other, while he is physically standing on the embankment, then we know how his brain should process them, to form Albert's experience.
Well, now how on observer on a train, observes the light will directly influence what they say about how the light physically strikes Albert. Do you agree with this? He says what he says, because he "physically" receives the information in a certain order, just like Albert. So his observations can't really be thrown away because they don't fit your argument. In fact I think this is the missing link.
We don't care about how the observer on the train will observe the light, we are interested in what the observer on the train says about how the photons will physically strike Albert's retinae, while Albert is standing on the embankment. Does his description of events correspond to the physical world? He says that the photons physically strike Albert's retinae in the order of one first, then the other, while Albert is standing on the embankment. If the photons physically strike Albert's retinae in the order of one first, then the other, while he is standing on the embankment, then given our postulate, his brain will process an experience where light flashes from one direction first, then the other.
Well if we assume postulate 1 is right, S' will process the information like Albert process information, in the order it is received.
We are interested in how S' corresponds to the physical; that is, the physicality of the photon striking events, because we know how Albert's brain will process photons which physically strike his retinae.
I meant my brain follows postulate 1.Sorry, I'm not sure what you mean by "so does mine", do you mean, "so does my brain [process photons in the order they are received]?
But S says that the light hit Albert's simultaneous, and as such Barry's brain will process the information as such, if this is physically accurate.Yes, but S' says that Albert's retinae get struck in the order of one first then the other; if this is physically accurate, then Albert's brain will process them in that order.
Yes
We start with our postulate, which tells us how Albert's brain processes photons which physically strike his retinae, while he is standing on the embankment.
YesS' says that the photons physically strike his retinae in the order of one first, then the other, while he is standing on the embankment.
NoIf the events, as described by S', correspond to the physical world; that is, if photons strike Albert's retinae in the order of one first, then the other, while he is standing on the embankment, then given our postulate, Albert's brain should process them in the order of one first, then the other, and produce an ordered experience.0 -
I would suggest a simplified version of the above. Instead of two eyes and a brain we have two photodetectors connected by two wires to a central unit that emits a flash of light when an electrical signal is simultaneously (and only simultaneously) received from the two photodetectors.
This is oriented as belowS' (the moving frame) y ^ | | d' d' | %-------*-------% | | O'-----------------------------------> x Velocity V--->
The two light detectors (%) are at a distance d' from the light flasher (*).
The whole frame moves with velocity V relative to a stationary frame and the electrical signal travels with velocity v' as measured in the moving frame.
To an observer in the moving frame S' light simultaneously hits the detectors and two electrical signals travel towards the centre. The two signals arrive simultaneously and the flash goes off.
Now the question is what happens when observed from the stationary frame?
Roosh, is this a reasonable simplification?0 -
No, Albert's memories are affected by the order in which the photons physically make contact with his retinae.citrus burst wrote: »So lets get some common ground. S says that the two photons hit Albert's eyes simultaneous? Albert's memories reflect this as per the postulate?
S' is moving relative to S?
S' detects one photon before the other, after they have reflected off Albert's eyes?
Somehow Albert's memories are affected by this?
The relatively moving observer doesn't just say that the light reflected from Albert's eyes arrives at him, the relatively moving observer, non-simultaneously, he says that the light hits Albert's eyes in the order of one first, then the other, and is reflected in that order.
By all means.citrus burst wrote: »I would like to add in another observer in Albert's frame, or as you like, standing next to Albert. Or at least, have Albert observing something.
Ah, OK; yes, we can idealise Albert so that his memories and experiences are infallible; or we can replace him with a less complicated, but more precise machine; I just think it helps to personalise the issue, because it can make the consequences more tangible.citrus burst wrote: »This was just to show that we can trust Albert's memory.
Indeed, "things" move relative to other "things", not relative to mathematical co-ordinates. As long as this is reflected in our reasoning there shouldn't be an issue.citrus burst wrote: »Well we need to make the distinction that some things are moving relative to other things. We can do it whatever we're comfortable with.
I assume the photons make contact with some sort of detector, can be detected by all all observers etc.
It might be easier to address this point with a question; if Albert's retinae are in S - because Albert is an observer in S - how can photons physically strike his retinae and those events don't occur in S?citrus burst wrote: »Sorry can you clarify what you mean by this?
Bearing in mind that the measurements of S', say, supposedly correspond to the physical world and imply that the photons physically strike Albert's retinae in the order of one first, then the other.
Yes, by relating them back to the physical world.citrus burst wrote: »And treat their observations correctly.
Indeed, this is why Albert should have discordant experiences, and why the apparent paradox arises.citrus burst wrote: »S also says he is standing on the embankment. But S says that they "physically" strike his retinas simultaneous.
If we know how Albert's brain processes photons which physically strike his retinae, we then only need to know the order in which photons physically strike his retinae.citrus burst wrote: »But this leads nothing to your argument.
S' says the strike in the order of one first, then the other, S says they strike together, "tied for first place"; given how Albert's brain processes photons which physically strike his retinae, this should lead to discordant experiences.
Look at the formulation again, we are talking prior to the original thought experiment where Albert sees the flashes simultaneously; in this pre-experiment testing of the lasers, he sees the flashes happen in the order of one first, then the other; this means that the photons struck his retinae in that order, not together.citrus burst wrote: »No they physically struck each other at the same time.
S' says that the photons make physical contact with Albert's retinae in the order of one first, then the other; so his brain should process an ordered experience which reflects this.citrus burst wrote: »Yes, I guess [it's true for all photons which make physically contact with an observers retinae].
Not necessarily, because we can consider two photons which arrive in the given order "in Albert's rest frame", where the velocity of a relatively moving observer doesn't matter; this is just to establish how Albert's brain processes photons which make physical contact with his retinae.citrus burst wrote: »But as we are debating, order is relative to velocity.
I don't see any real problem with this, as long as it doesn't lead to us having to consider photons which physically hit Albert's retinae "in one frame", as being different to photons which strike Albert's retinae "in a different reference frame".citrus burst wrote: »At this point, I'm just going to stop and throw in another postulate. Albert's brain stops detecting photons after they are detected. This ok?
As in it only detects a photon once.
Yes, but S' says that the photons physically hit Albert's retinae in the order of one first, then the other, and were reflected in that order.citrus burst wrote: »So in this case. Laser fired, hits Albert's eye, detected, some is reflected and detected by S'.
If they physically hit Albert's retinae in that order, then his brain will process them as an ordered experience.
Albert's brain doesn't process photons which strike the retinae of a relatively moving observer.citrus burst wrote: »Yes but if we use are new postulate, Albert's brain stop detecting the photons before they reached S'.
That is part of the problem with saying "before they reached S'"; S' isn't something physical which the photons reach; S' describes the physical events mathematically. "Albert" is also "in" S', to the extent that he is represented by co-ordinates in S'.
S' says that the photons physically strike Albert's retinae non-simultaneously, or at least, he calculates that they do; by taking the flight time of the light reflected from Albert's retinae. If his measurements are correct, then the conclusion is that the photons physically struck Albert's retinae in the order of one first, then the other.citrus burst wrote: »No they are detected none simultaneous.
I could empathise alright, but the issue is that taking such short cuts can cloud our reasoning; we need to be clear on what it is that is being said.citrus burst wrote: »Or we could avoid this issue, by only using mathematical reference frames. You assume the problem arises from the use of them, after reading "physically strike Albert's retinae in the order of one first" 30+ times in one post it gets a bit tiresome and we can be forgiven for taking short cuts like using S instead of "Albert's rest frame"
Indeed, but S' says they physically struck Albert's retinae in the order of one first, and then the other, and that they were refelected in this order. The order in which they physically strike Albert's retinae determines his experiences.citrus burst wrote: »But if we use postulate 2, Albert's brain stopped detecting the photons after they hit his eye.
But he calculates back and determines, on the basis of his measurements, that the events, which were simultaneous in S, are non-simultaneous in S'; that is, his measurements lead him to the conclusion that the photons physically struck Albert's retinae in the given order.citrus burst wrote: »Well, now how on observer on a train, observes the light will directly influence what they say about how the light physically strikes Albert. Do you agree with this? He says what he says, because he "physically" receives the information in a certain order, just like Albert. So his observations can't really be thrown away because they don't fit your argument. In fact I think this is the missing link/
If they didn't physically strike Albert's retinae in the given order, then the relatively moving observers observation of non-simultaneous events is an optical illusion.
Indeed, the observer in S' will; but if the description of events, or the calucations that the observer in S' performs are deemed to be accurate, then the implication is that the photons physically struck Albert's retinae in the given order; if they struck Albert's retinae in that order, then Albert's brain will process an ordered experience.citrus burst wrote: »Well if we assume postulate 1 is right, S' will process the information like Albert process information, in the order it is received.
Ok, I was thinking that, but wasn't 100% on it.citrus burst wrote: »I meant my brain follows postulate 1.
Barry's brain won't process photons which hit Albert's retinae, only phtons which hit his; if photons hit his retinae simultaneously, then his brain will process a simultaneous experience - that would just represent the other side of the same paradox-coin.citrus burst wrote: »But S says that the light hit Albert's simultaneous, and as such Barry's brain will process the information as such, if this is physically accurate.
Why not, it follows from our postulate.citrus burst wrote: »No0 -
Hey dlouth, we can simplify it using the observer also; we can idealise the observer to say that this is how his brain functions; that there is a "centre of processing" where signals from the retinae must travel to to be processed, with the dimensions of your circuit above.I would suggest a simplified version of the above. Instead of two eyes and a brain we have two photodetectors connected by two wires to a central unit that emits a flash of light when an electrical signal is simultaneously (and only simultaneously) received from the two photodetectors.
This is oriented as belowS' (the moving frame) y ^ | | d' d' | %-------*-------% | | O'-----------------------------------> x Velocity V--->
The two light detectors (%) are at a distance d' from the light flasher (*).
The whole frame moves with velocity V relative to a stationary frame and the electrical signal travels with velocity v' as measured in the moving frame.
To an observer in the moving frame S' light simultaneously hits the detectors and two electrical signals travel towards the centre. The two signals arrive simultaneously and the flash goes off.
Roosh, is this a reasonable simplification?
Personally, I think it helps to make it a bit more tangible if we speak about the experiences produced by the brain; even if it is an idealised version of it. We could perhaps speak about an observer having been cryogenically frozen and then being re-animated in the future, where his visual network is replaced by this simplistic circuitry.
This is the issue; we're not interested in how a relatively moving observer will measure Albert's brain activity, or the conclusion he will draw about Albert's experiences; we are interested in how Albert's brain processes photons which physically make contact with his retinae. We know that his brain processes them in the order they make physical contact with his retinae, and this holds true for our simplified visual network.Now the question is what happens when observed from the stationary frame?
The only pertinent question then is, do the photons physically strike his retinae in the order of one first, and then the other, while he is standing on the embankment? If they do, then his brain will process them as an ordered experience.0 -
I've no problem with that. The important thing is that we've reduced it to three spacetime events. 1) the left detector firing; 2) the right detector firing and 3) the central point receiving the signals.Hey dlouth, we can simplify it using the observer also; we can idealise the observer to say that this is how his brain functions; that there is a "centre of processing" where signals from the retinae must travel to to be processed, with the dimensions of your circuit above.
Personally, I think it helps to make it a bit more tangible if we speak about the experiences produced by the brain; even if it is an idealised version of it. We could perhaps speak about an observer having been cryogenically frozen and then being re-animated in the future, where his visual network is replaced by this simplistic circuitry.
I agree. If light hits one retina and then the other in Albert's frame (whether stationary or moving), he will experience two events. This is because the eyes, the transmission mechanism and the brain (which we're considering to be point-like) are all fixed within Albert's frame.This is the issue; we're not interested in how a relatively moving observer will measure Albert's brain activity, or the conclusion he will draw about Albert's experiences; we are interested in how Albert's brain processes photons which physically make contact with his retinae. We know that his brain processes them in the order they make physical contact with his retinae, and this holds true for our simplified visual network.
The only pertinent question then is, do the photons physically strike his retinae in the order of one first, and then the other, while he is standing on the embankment? If they do, then his brain will process them as an ordered experience.0 -
Cool.I've no problem with that. The important thing is that we've reduced it to three spacetime events. 1) the left detector firing; 2) the right detector firing and 3) the central point receiving the signals.
Photons don't physically strike Albert's retinae "in 'Albert's' reference frame", because "Albert's reference frame" is a set of mathematical co-ordinates which don't exist a priori in nature. Photons only physically strike Albert's retinae in the physical world, where Albert is standing on the embankment.I agree. If light hits one retina and then the other in Albert's frame (whether stationary or moving), he will experience two events. This is because the eyes, the transmission mechanism and the brain (which we're considering to be point-like) are all fixed within Albert's frame.
The mathematical reference frames [attempt to] describe events in the physical world; "Albert's reference frame", or S, says that the photons physically strike Albert's retinae together, or "tied for first place", while Albert is standing on the embankment; "not Albert's reference frame", or S', says that the photons physically strike Albert's retinae in the order of one first then the other, while Albert is standing on the embankment.
In the physical world, Albert's brain processes photons, which physically strike his retinae, in the order they strike his retinae, while he is standing on the embankment.
S' says that the photons physically strike his retinae in the order of one first, then the other, while he is physically standing on the embankment; if the description given by S' corresponds to the physical world, such that the photons do physically strike his retinae in the order of one first then the other, while he is standing on the embankment, then his brain will process an ordered experience.0 -
Apologies, I forgot to reply to this post.
We don't need to reference any reference frames initially, we can just establish how Albert's brain processes physical stimuli. We know that, while Albert is physically standing on the embankment, his brain will process all photons, which physically strike his retinae, in the order they are received; that is, if photons physically strike his retinae in the order of one first then the other, while he is standing on the embankment, his brian will process them in that order.
The above is not true, as the order is reference-frame dependent. Instead, it is the causal structure of events that defines what Albert perceives. All reference frames agree on the causal structure of events.0 -
Could you draw a simple diagram for your setup? I think the problem is easy to solve but I don't want to get bogged down in confusion over this or that detail. The thread is a bit hard to follow.Cool.
Photons don't physically strike Albert's retinae "in 'Albert's' reference frame", because "Albert's reference frame" is a set of mathematical co-ordinates which don't exist a priori in nature. Photons only physically strike Albert's retinae in the physical world, where Albert is standing on the embankment.
The mathematical reference frames [attempt to] describe events in the physical world; "Albert's reference frame", or S, says that the photons physically strike Albert's retinae together, or "tied for first place", while Albert is standing on the embankment; "not Albert's reference frame", or S', says that the photons physically strike Albert's retinae in the order of one first then the other, while Albert is standing on the embankment.
In the physical world, Albert's brain processes photons, which physically strike his retinae, in the order they strike his retinae, while he is standing on the embankment.
S' says that the photons physically strike his retinae in the order of one first, then the other, while he is physically standing on the embankment; if the description given by S' corresponds to the physical world, such that the photons do physically strike his retinae in the order of one first then the other, while he is standing on the embankment, then his brain will process an ordered experience.0 -
The diagram you drew is perect; we just need to relate it back to the physical world. Imagine that your '%' are Albert's retinae and the '*' is the "processing centre" of the brain, in Albert's futuristic visual network. We then just need to imagine Albert standing on an embankment and then imagine two photons physically striking his retinae; where they come from is not necessarily important, all that is important is the order in which they physically strike the retinae.Could you draw a simple diagram for your setup? I think the problem is easy to solve but I don't want to get bogged down in confusion over this or that detail. The thread is a bit hard to follow.
I'm guessing your solution is to say that, from the perspective of a relatively moving observer, the signals from the retinae will converge on the processing centre simultaneously, even if they strike the retinae asynchronously. The issue is that we aren't interested in how a relatively moving observer will, supposedly, measure Albert's brain activity, or the conclusion he will, supposedly, arrive at with regards to Albert's experience.
What we are interested in is how Albert's brain processes Albert's experiences, or more pointedly, how Albert's brain will process photons which physically strike his retinae, while he is standing on the embankment.
We know that Albert's brain will process photons which physically strike his retinae, while he is standing on the embankment, in the order they physically strike his retinae; because this is how Albert's brain processes Albert's experiences in the physical world - as opposed to what a relatively moving observer will, supposedly, measure.
S' says that the photons physically strike Albert's retinae in the order of one first, then the other, while he is physically standing on the embankment; if this is accurate, then Albert's brain will process an ordered experience.0 -
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But he calculates back and determines, on the basis of his measurements, that the events, which were simultaneous in S, are non-simultaneous in S'; that is, his measurements lead him to the conclusion that the photons physically struck Albert's retinae in the given order.
Think about what you are saying here. Barry in S' receives information about an event that was at rest to him. Uses some means to determine, how that event happened, in the place that is at rest to him. Therefore reasons that this is wrong and he is right, since this is how he measured it. That Albert's measurement of simultaneous light strikes was incorrect and his was correct. That Albert's measurement is invalid, because Barry is in a "special frame" of higher importance then Albert's. That Albert's memories should follow that he was not, in fact blinded in both eyes, but rather in one first, then the other, despite, what Albert thinks.
This is to me is a big hole in your argument. You have put one reference frame on a plate and declared it special. You may not have meant it, but from your explanation, you have confirmed it. This is in contradiction to what Galileo, Newton and later Einstein did and said that all reference frames are equal. Special relativity postulate one.
What actually happens is Barry, in S', receives information from S, that the light struck Albert's eyes non-simultaneous, according to his reference frame. He then calculates back, knowing the speed he is moving relative to Albert and the timing between the two light strikes, that in Albert's frame S, the light "physically" hit Albert simultaneously, as per what Albert measured. There is no contradiction between Albert's memories and his measurements.
See optical illusion is a bad choice of words and makes me laugh. How can what our number one sensory organ detect be an "illusion." It gets the information, its up to the brain to process the information. Its the brain that makes false conclusions, that seem to cause the optical illusion.If they didn't physically strike Albert's retinae in the given order, then the relatively moving observers observation of non-simultaneous events is an optical illusion.
The classic example being a mirage. The optical illusion is that the brain thinks it sees water. What it actually see's is the reflection of the sky, but it determines it is water, in a vain attempt to save its life.
The illusion in this case, I guess is that we think that events are simultaneous for us, should be simultaneous for everywhere. But due to the finite speed of light, this might not the case.
Its unintuitive, and it should be. Its not an "optical illusion" but a part of the universe's nature.
See above for proper treatment of reference frames and measurement.Indeed, the observer in S' will; but if the description of events, or the calucations that the observer in S' performs are deemed to be accurate, then the implication is that the photons physically struck Albert's retinae in the given order; if they struck Albert's retinae in that order, then Albert's brain will process an ordered experience.Barry's brain won't process photons which hit Albert's retinae, only phtons which hit his; if photons hit his retinae simultaneously, then his brain will process a simultaneous experience - that would just represent the other side of the same paradox-coin.
Well I was assuming that some of the photons, bounce of Albert's eyes, in order to be detected by another reference frame. If all the photons fired by the laser were detected by Albert, then the whole experiment would be null and void.
I don't like that we use Albert as both a detector and an observer, it adds a certain complication that we don't really need.
I'd prefer to have one laser, that's beam is split and reflected by two mirrors. The light from the two lasers is redirected to two arbitrary points that are equidistant apart. The whole point of the set up is to make sure that the beams are in phase with each other and travel the same distance.
Then Albert, in the same frame as the set up, using some experimental set up, determines the time interval between the light from the two beams hitting the two arbitrarily chosen points.
Barry, moving relative to Albert also has an identical set up to Albert to determine the time interval between the two beams hitting the two arbitrary points.0 -
OK so the apparatus with the two detectors is stationary in a frame S and there is a moving frame S'. Is that the correct setup? I'll assume it is.S' says that the photons physically strike Albert's retinae in the order of one first, then the other, while he is physically standing on the embankment; if this is accurate, then Albert's brain will process an ordered experience.
From the point of view of the stationary frame there is no problem and the two detectors will be activated simultaneously and the electrical signal will travel towards the centre and activate the central processing unit.
From the point of view of the S' (moving relative to S), the detectors will fire non-simultaneously, however applying the Lorentz transformation, the velocities of the electrical signals as well as the lengths those signals have to travel will be transformed in such a way that the signals still arrive at the central point at the same time. The central processing unit still flashes.
Therefore even though the light detectors viewed from S' are activated at different times, the observer in S' can see that Albert still perceives the events as simultaneous (i.e. the flash)
Now does any of this violate causality or physicality or whatever? No. It would only violate causality if either or both of the light detection events occurred before the flash. But this does not happen under the Lorentz transformation.
The other thing that would violate physicality would be if the any signal was observed to be travelling faster than the speed of light. Again this does not happen under the Lorentz transformation.
Every observer in every frame sees a plausible physical situation.0 -
There is no need to treat any reference frame as special; the whole issue arises because we treat the description of retinae striking events, given by both reference frames as equally real, or equally physical.citrus burst wrote: »Think about what you are saying here. Barry in S' receives information about an event that was at rest to him. Uses some means to determine, how that event happened, in the place that is at rest to him. Therefore reasons that this is wrong and he is right, since this is how he measured it. That Albert's measurement of simultaneous light strikes was incorrect and his was correct. That Albert's measurement is invalid, because Barry is in a "special frame" of higher importance then Albert's. That Albert's memories should follow that he was not, in fact blinded in both eyes, but rather in one first, then the other, despite, what Albert thinks.
This is to me is a big hole in your argument. You have put one reference frame on a plate and declared it special. You may not have meant it, but from your explanation, you have confirmed it. This is in contradiction to what Galileo, Newton and later Einstein did and said that all reference frames are equal. Special relativity postulate one.
As we have mentioned before, reference frames, of the type S and S', are mathematical depictions of physical events; observers are not phyiscally "in" the mathematical reference frames, the mathematical reference frames represent the physical observers using a set of co-ordinate labels. So Albert isn't in a "special frame", Albert is physically located on the embankment; this is only "special" to the degree that it represents the physical scenario.
S and S' describe event which physically happen to Albert, while he is physically standing on the embankment. There are certain things we know about how Albert's brain produces Albert's experiences, when photons physically strike his retinae. Using the information about the physical retinae striking events, from both S and S' - which we treat as being equally phyiscal - we can deduce how Albert's brain would process such events, because we know how his brain operates in the physical world; not some "special" mathematical reference frame.
Again, the issue appears to be that you are talking about how a relatively moving observer will, supposedly, measure Albert's brain activity and the conclusion he will, supposedly, draw about Albert's experience. We're not interested in that though, we're interested in how Albert's brain processes photons which physically strike his retinae, while he is standing on the embankment; we're interested in the physicality of the retinae striking events, as described by the mathematical reference frames; and we're interested in the order in which the photons physically strike Albert's retinae.
Again, Albert and Barry aren't physically "in" S and S', respectively; Albert is physically on the embankment and Barry is physically on the train; S and S' are mathematical representations of the physical events, which [are supposed to] aid both observers in any calculations they might try to make.citrus burst wrote: »What actually happens is Barry, in S', receives information from S, that the light struck Albert's eyes non-simultaneous, according to his reference frame. He then calculates back, knowing the speed he is moving relative to Albert and the timing between the two light strikes, that in Albert's frame S, the light "physically" hit Albert simultaneously, as per what Albert measured. There is no contradiction between Albert's memories and his measurements.
The description of events given by S', be they caluclations, measurements or whatever form they take, says that the photons physically strike Albert's retinae while he is physically standing on the embankment, in the order of one first, then the other; if this description corresponds to physical events, such that Albert's retinae are struck in the given order, while he is standing on the embankment, then Albert's brain will process them in that order; because that is how Albert's brain operates in the physical world, to produce Albert's experiences.
We can try and find another phrase if needs be, but I think serves the intended purpose here.citrus burst wrote: »See optical illusion is a bad choice of words and makes me laugh. How can what our number one sensory organ detect be an "illusion." It gets the information, its up to the brain to process the information. Its the brain that makes false conclusions, that seem to cause the optical illusion.
The classic example being a mirage. The optical illusion is that the brain thinks it sees water. What it actually see's is the reflection of the sky, but it determines it is water, in a vain attempt to save its life.
The illusion in this case, I guess is that we think that events are simultaneous for us, should be simultaneous for everywhere. But due to the finite speed of light, this might not the case.
And the nature of the brain is to process photons which physically strike an observer's retinae in the order they are received, when that observer is standing on an embankment, say, in the physical world.citrus burst wrote: »Its unintuitive, and it should be. Its not an "optical illusion" but a part of the universe's nature.
See replies.citrus burst wrote: »See above for proper treatment of reference frames and measurement.
I understood that, but that wasn't what the statement said:citrus burst wrote: »Well I was assuming that some of the photons, bounce of Albert's eyes, in order to be detected by another reference frame. If all the photons fired by the laser were detected by Albert, then the whole experiment would be null and void.
Barry's brain won't process the information "as such", where "as such" means that light hits Albert's retinae simultaneously. The information that Barry's brain will process will be from the photons which physically impact his own retinae.citrus burst wrote: »But S says that the light hit Albert's simultaneous, and as such Barry's brain will process the information as such, if this is physically accurate.
It doesn't matter either way, we are only interested in the physicality of the photons which strike Albert's retinae, and the order in which they physically strike Albert's retinae. The information that Barry has, says that the photons physically strike Albert's retinae in the order of one first, then the other. If this information is correct, and Albert's retinae are struck in the given order, the we know how Albert's brain will process the photons.
The issue is that, in the physical world, Albert is both a detector and an observer; that's the function his senses play; we can idealise Albert such that his senses are infallible, or we can idealise him such that he has been cryogenically frozen and re-animated in the future, with some of his sensory system replaced by infallible machinery.citrus burst wrote: »I don't like that we use Albert as both a detector and an observer, it adds a certain complication that we don't really need.
Personalising it in this manner helps to crystalise it in the mind, I find; it's more difficult to dismiss an experience we ourselves could relate to; it makes it that much less abstract and that much more tangible. It also helps us avoid any philosophical assumptions about clocks and time.
I was thinking of a somewhat different thought experiment also, that didn't necessarily involve an observers experience, but I don't think it is neecssary. We can idealise Albert and stick with him; as I mentioned, I think it makes it that much more tangible.citrus burst wrote: »I'd prefer to have one laser, that's beam is split and reflected by two mirrors. The light from the two lasers is redirected to two arbitrary points that are equidistant apart. The whole point of the set up is to make sure that the beams are in phase with each other and travel the same distance.
Then Albert, in the same frame as the set up, using some experimental set up, determines the time interval between the light from the two beams hitting the two arbitrarily chosen points.
Barry, moving relative to Albert also has an identical set up to Albert to determine the time interval between the two beams hitting the two arbitrary points.0 -
I would clarify this somewhat and say that Albert - the apparatus with the two detectors - is standing on the embankment; the mathematical reference frames, S and S', reflect this physical situation; both label him as at rest relative to the platform and in motion relative to Henry, on the train.OK so the apparatus with the two detectors is stationary in a frame S and there is a moving frame S'. Is that the correct setup? I'll assume it is.
The key point is that we are not interested in how the observer moving relative to Albert will, supposedly, measure Albert's brain function, nor are we interested in the conclusion he will, supposedly, arrive at about Albert's experiences. We are interested in how Albert's brain processes photons which physically strike his retinae, to process his experiences; we know that his brain processes photons which physically strike his retinae in the order in which they physically strike his retinae, while he is standing on the embankment.citrus burst wrote: »From the point of view of the stationary frame there is no problem and the two detectors will be activated simultaneously and the electrical signal will travel towards the centre and activate the central processing unit.
From the point of view of the S' (moving relative to S), the detectors will fire non-simultaneously, however applying the Lorentz transformation, the velocities of the electrical signals as well as the lengths those signals have to travel will be transformed in such a way that the signals still arrive at the central point at the same time. The central processing unit still flashes.
Therefore even though the light detectors viewed from S' are activated at different times, the observer in S' can see that Albert still perceives the events as simultaneous (i.e. the flash)
We are interested, however, in the physicality of the photon striking events, as described by S'; we are interested in this because we know how Albert's brain will process photons which physically strike his retinae, while he is standing on the embankment.
According to the description of physical event given by S', the photons physically strike Albert's retinae in the order of one first, then the other, while he is physically standing on the embankment. If the photons physically strike Albert's retinae in this order, while he is standing on the embankment, then his brain will process them as an ordered experience.
It probably isn't a violation of causality, but extrapolating this to your set-up where the light flashes, it means that the light should both flash and not flash; which would seem to represent a paradox.citrus burst wrote: »Now does any of this violate causality or physicality or whatever? No. It would only violate causality if either or both of the light detection events occurred before the flash. But this does not happen under the Lorentz transformation.
The other thing that would violate physicality would be if the any signal was observed to be travelling faster than the speed of light. Again this does not happen under the Lorentz transformation.
Every observer in every frame sees a plausible physical situation.0 -
So S is the platform and S' is the train?I would clarify this somewhat and say that Albert - the apparatus with the two detectors - is standing on the embankment; the mathematical reference frames, S and S', reflect this physical situation; both label him as at rest relative to the platform and in motion relative to Henry, on the train.
If this is the case, then the light will hit his eyes as per our experiment set up. If the two mirrors are the same distance apart then the light will arrive simultaneous. If we move one of the mirrors, the light will arrive non-simultaneous. And that's pretty much it. Albert's memories are affected as per postulate one.The key point is that we are not interested in how the observer moving relative to Albert will, supposedly, measure Albert's brain function, nor are we interested in the conclusion he will, supposedly, arrive at about Albert's experiences. We are interested in how Albert's brain processes photons which physically strike his retinae, to process his experiences; we know that his brain processes photons which physically strike his retinae in the order in which they physically strike his retinae, while he is standing on the embankment.
But as you said, we don't care about what an observer in S' says, so S' is null and might as well not exist. Our problem is solved.We are interested, however, in the physicality of the photon striking events, as described by S'; we are interested in this because we know how Albert's brain will process photons which physically strike his retinae, while he is standing on the embankment.
But there is nothing in S' to make an observation/measurement and/or we are choosing to ignore it.According to the description of physical event given by S', the photons physically strike Albert's retinae in the order of one first, then the other, while he is physically standing on the embankment. If the photons physically strike Albert's retinae in this order, while he is standing on the embankment, then his brain will process them as an ordered experience.It probably isn't a violation of causality, but extrapolating this to your set-up where the light flashes, it means that the light should both flash and not flash; which would seem to represent a paradox.
I don't remember saying this??
Yes the two photons will interfere?
I don't know what you mean0 -
Roosh, I was going to reply to your previous post but I think at this point it would be best if we start again with a clear description of the current setup. It is hard to figure out what is going on by reading through the thread. I'm getting very confused and its a confusing subject to begin with. One thing I think is important is that things are discussed in terms of observable spacetime events (i.e. something that occurs at a particular point at a particular time (wrt whatever frame of reference). A basic picture too will help.0
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It was me that said that. I proposed a setup with two light detectors and a central flash that goes when a signal from each arrives at the central point. Unfortunately you were attributed to the quote.citrus burst wrote: »
I don't remember saying this??
Yes the two photons will interfere?
I don't know what you mean0 -
The co-ordinates of S are used to describe the position and motion of the relatively moving train, and observer, so S cannot simply refer to the physical platform; similarly, the co-ordinates of S' describe Albert's position on the platform, and the platform itself, so it cannot simply be the train.citrus burst wrote: »So S is the platform and S' is the train?
Which experimental set-up are you referring to here? The one we've been discussing is where S describes the retinae striking events as simultaneous; the Loretnz transform gives us the co-ordinates of those events in S'; according to S' the events are non-simultaneous; that is, S' says that the photons physically strike Albert's retinae in the order of one first, then the other. If they physically strike his retinae in that order, then that is how his brain will process them.citrus burst wrote: »If this is the case, then the light will hit his eyes as per our experiment set up. If the two mirrors are the same distance apart then the light will arrive simultaneous. If we move one of the mirrors, the light will arrive non-simultaneous. And that's pretty much it. Albert's memories are affected as per postulate one.
We're not interested in how he measures Albert's brain activity, becuase Albert's brain doesn't produce Albert's experiences from the perspective of a relatively moving observer.citrus burst wrote: »But as you said, we don't care about what an observer in S' says, so S' is null and might as well not exist. Our problem is solved.
We are interested in the physicality of the retinae striking events, however, because Albert's brain does process photons which physically strike his retinae.
We can have the light reflect from Albert's retinae to the relatively moving observer, this won't change the fact that S' says the photons physically strike Albert's retinae in the order of one first, then the other. Using only the co-ordinates of S we can get the co-ordinates of S', without any observer necessary, because we can calculate what he would measure; and we calculate that he would conclude that the photons physically strike Albert's retinae in a given order.citrus burst wrote: »But there is nothing in S' to make an observation/measurement and/or we are choosing to ignore it.
Apologies, it was dlouth that said that; but we can apply his formulation to make the result less observer centred.citrus burst wrote: »I don't remember saying this??
Yes the two photons will interfere?
I don't know what you mean
We can speak about re-animated Albert, after the cryogenic freezing and the surgery to replace his visual network with dlouths simplistic yet precice network; we can even attach a light bulb to him, such that it switches on if, and only if, the signals from his two retinae arrive at the idealised "processing centre" simultaneously, or "tied for first place"; as opposed to in the order of one first, then the other.
If the photons physically strike his retinae in the order as specified by S', then the light doesn't switch on; if they physically strike in the order specified by S, then it does.
Relativity says both are equally true; that is, that the photons physically strike his retinae in the order of one first, then the other, while he is physically standing on the embankment; and, they physically strike his retinae "tied for first place", while he is physically standing on the embankment.
If this is true then the light should both turn on, and not turn on. We can have it such that it detonates a bomb also, if we want to make it more dramatic; such that a building both gets demolished and doesn't get demolished.0 -
Hey dlouth, I can understand that it's getting confusing alright. I think it is fair to discuss things by referring to observable spacetime events, as long as we relate it back to the physical world, where the events occur.Roosh, I was going to reply to your previous post but I think at this point it would be best if we start again with a clear description of the current setup. It is hard to figure out what is going on by reading through the thread. I'm getting very confused and its a confusing subject to begin with. One thing I think is important is that things are discussed in terms of observable spacetime events (i.e. something that occurs at a particular point at a particular time (wrt whatever frame of reference). A basic picture too will help.
Set-up
The set-up is quite simple really, we can take the diagram you drew earlier and say that it represents Albert's replaced visual network - after he was cryogenically frozen and re-animated. We can also attach the light to Albert's head, as per your network, so we can have the best of both worlds.
Essentially, the '%' in your diagram can represent Albert's retinae; the '*' can represent the processing centre which produces both Albert's experience and the signal to switch on the light on Albert's head.
Albert is standing on an embankment, located midway between two lasers, A and B; he is positioned in such a way that his left retina is the same distance from A as his right retina is from B.
Albert's brain
I think it is important to set out how Albert's brain functions, in the physical world, to produce Albert's experiences. As far as Albert's brain is concerned, the time it takes for a signal to travel form % to * (retina to processing centre) is the same for both % (retinae); this is how it produces Albert's experiences, while Albert is physically standing on the embankment.
Albert's brain will process photons which physically strike his retinae, while he is standing on the embankment, in the order they strike his retinae.
Reference frames
The mathematical reference frames, S and S', can be used to describe events which happen in the physical world; the co-ordinates of S can be used to ascertain the co-ordinates of S', using the Lorentz transform, and vice versa.
According to the reference frame S, the photons physically strike Albert's retinae together, or "tied for first place", while Albert is physically standing on the platform.
According to S', the photons physically strike Albert's retinae in the order of one first, then the other, while he is standing on the embankment.
If both of these descriptions correspond to physical events, it means that the photons physically strike Albert's retinae in the order of one first, then the other, while he is physically standing on the embankment; and they physically strike his retinae together, or "tied for first place".
Knowing what we do about how Albert's brain will process photons, which physically strike his retinae while he is standing on the embankment, if both these descriptions represent physical events, then the light on Albert's head should both light up and not light up.0 -
How are the two frames S and S' moving relative to Albert?According to S', the photons physically strike Albert's retinae in the order of one first, then the other, while he is standing on the embankment.
If both of these descriptions correspond to physical events, it means that the photons physically strike Albert's retinae in the order of one first, then the other, while he is physically standing on the embankment; and they physically strike his retinae together, or "tied for first place".
Knowing what we do about how Albert's brain will process photons, which physically strike his retinae while he is standing on the embankment, if both these descriptions represent physical events, then the light on Albert's head should both light up and not light up.0 -
It depends on what you mean by "Albert".How are the two frames S and S' moving relative to Albert?
Albert, the physical observer standing on the embankment, is not moving relative to the co-ordinate labels of either S or S', because those co-ordinate labels do not exist a priori in nature; they're not physical, so physical observers cannot move relative to them.
If you mean the co-ordinate labels which represent Albert in both reference frames, then the co-ordinate labels which represent Albert are labeled as "at rest" relative to the co-ordinate lables which constitue S, but are labeled as "in motion" relative to S'.
Albert is not physically in S or S', because S and S' are not physical; S and S' prime attempt to describe events which happen in the physical world. Albert is physically standing on the embankment, at rest relative to it, and both mathematical reference frames reflect this. The photons do not strike Albert's retinae "in" the mathematical reference frame, the reference frames describe how the photons strike Albert's retinae, while he is standing on the embankment.
S' says the photons physically strike Albert's retinae in the order of one first, then the other, while he is physically standing on the embankment. If the photons physically strike Albert's retinae in that order, while he is standing on the embankment, then his brain will process an ordered experience; because that is how his brain processes photons which physically strike his retinae, in that order.0 -
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