christopherkirkreves

Hello again. I understand that you all think I’m just blinded to the truth that has been clearly laid out here before me by everyone in this thread due to me be so wedded to my own odd interpretation of this theory I can’t see anything other than my own ideas. Okay. There is an old trick in therapy (and perhaps this thread needs some therapy) where the one party is required to say what he (or she) believes the other party is saying. One of the hardest parts for me in this thread is that I’m being told that I’m wrong by several different people, but they are telling me that I am wrong for several different reasons, and those different reasons don’t necessary correspond with one another. And so, what follows is my attempt to say what I believe you all are saying, and to put these various ideas into one argument, and to then also include what I believe is the consequences of these arguments. The easy response to this is to say “Christopher, you’re just saying the same thing over and over and not listening.” And you may very well be justified in saying that because you really believe that I’m not trying to create some daylight in this discussion where we can really point out our disagreements and then discuss them. I’m trying. ----- This is what I think you all are saying (and the consequences): When it comes to the “Two Lightning Bolt Strikes” thought experiment if by stipulating that the two lightning bolt strikes occur simultaneously in one inertial frame of reference then this means the man in that inertial frame of reference will see the two flashes of light at the same time and this means the man in the other inertial frame of reference will see (encounter) one flash of light before the other then this means the man in the one frame of reference is actually at rest and the man in the other frame of reference is actually in motion and so the “Two Lightning Bolt Strikes” thought experiment is a test of absolute rest because for the one man to encounter the two flashes of light at the same time he must remain at rest at the midpoint between where the two flashes of light occurred and for the other man to encounter one flash of light before the other he must move away from the midpoint unless by stipulating that the two flashes of light occur simultaneously in one inertial frame of reference means also stipulating that the two flashes of light do not occur simultaneously for the man in the other inertial frame of reference and so neither man moves and so this is then not a test of absolute rest but rather it is the two flashes of light that move to both men but since it was stipulated that the two flashes of light occurred simultaneously for the one man and this also means it is stipulated that the two flashes of light do not occur simultaneously for the other man and so the two flashes of light travel equal distances at equal velocities to both men, but for the one man they left their points of origin at the same time, and so he encounters them at the same time, while for the other man they left their points points of origin one before the other, and so he will encounter one before the other but this means the conclusion of this thought experiment (“events which are simultaneous in one inertial frame of reference are not simultaneous in another”) is also a stipulated to premise of this thought experiment. For those of you who think that the “Two Lighting Bolt Strikes” thought experiment does not prove anything but is just a demonstration of how Relativity works will be just fine that this thought experiment assumes as one of its premises “events which are simultaneous in one inertial frame of reference are not simultaneous in another.” But if you think that this thought experiment proves something then the above logic shows that the “Two Lightning Bolt Strikes” thought experiment does not work, because it either leads to a test of absolute rest (which is unacceptable) or it assumes it conclusion (which is also unacceptable). Either way, whether Einstein intended prove or did not intent to prove “events which are simultaneous in one inertial frame of reference are not in another” he does not. And so, with many of you I am in agreement, he does not prove this. However, Comstock’s “One Light Bulb in a Moving Car” thought experiment, given the four axioms, does prove (in the sense of the thought experiment) “events which are simultaneous in one inertial frame of reference are not simultaneous in another.” And he only needs to assume the four axioms to do this and not also to assume the conclusion “events which are simultaneous in one inertial frame of reference are not in another” to do this. And in his thought experiment both men remain at rest and so there is no danger of having to say one is actually at rest and the other is actually in motion and so becoming a test of absolute rest. Now, if any of you who agree with me that Einstein’s “Two Lightning Bolt Strikes” thought experiment does not prove “events which are simultaneous in one inertial frame of reference are not in another” (because he did not intend to (or even though he intended to)) also think that Comstock’s thought experiment does not prove “events which are simultaneous in one inertial frame of reference and not simultaneous in another” in the same way as Einstein’s does not, then make you case. Let’s switch roles. You make an affirmative case as to why Comstock failed, and I will take on your role as the critiquers. And, of course, you could always just respond with “Christopher, you just don’t listen, so you wrong, but I’m just done wasting my time.” Okay. I think I’m listening. I think I’m trying very hard to understand your various, and at time conflicting, critiques of me. And where I have agreed I have admitted to be wrong, and where I have disagreed I have tried to state the reason(s) why. And where I have felt like I have been told I’m wrong for the same reason over and over, I have tried to vary my responses to try to get to a clearer understand of our differences. And he above piece of logic is, yet again, an attempt at a varied response. ------------- To studiot: “I do not like holding discussion with those who declare "whatever you are going to say is irrelevant", without knowing what I actually want to say.” Really? I believe I have put up with a lot of unnecessary hate and rudeness in this thread that did not in any way advance the discussion. And I believe I answered your questions the first time you asked them. And while it may have been rude of me to anticipate your response and so then also give my response (“it is irrelevant”) to your anticipated response when answering your question again (“It is all in the embankment”), are you, a denizen of the Internet and this forum, saying that what I did was so rude (and I’ll admit there was some rudeness to it) and so far beyond what is commonly found in this and other forums that your sensibilities keep you from stating the “explanation of the relativity of simultaneity” that you had already ready for me, but you just needed to know the “all important” point of where I believed the two lightning bolt strikes occurred (which is “in the embankment”)? -------- To swansont: “Certainly not 1905, when Einstein derived them from the postulate of invariant c,” You are right. At various times Einstein constructed his theory is various ways. And you are right, in 1905, in “On The Electrodynamics of Moving Bodies,” he proves “clocks synchronized in one inertial frame of reference are not synchronized in another,” based on the postulate of the invariant nature of light for all observers, and then by proving length contraction. “Observers moving with the moving rod would thus find that the two clocks were not synchronous while the observers in the stationary system would declare the clocks to be synchronous.” (see A. Einstein, “Zur Elektrodnamik bewegter Koper,” Annalen der Physik, 17, 1905) But by 1916 he had changed the structure of his theory. In his 1905 thought experiment he had to rely on clocks to prove the relativity of simultaneity. And in his 1905 thought experiment he had to first work though a small bit of simple math, and then first prove “length contraction,” to then prove the relativity of simultaneity. In his 1916 book (as well as in his 1916 paper) he seems to be doing what Comstock had done, and he seems to think he is doing it better (because he eliminated the need to clocks). So, yes, you can go through the various papers published by Einstein and make the argument that the Lorentz transformations are not based on the relativity of simultaneity. But, in his book, that was, I think, without argument, his most prominent construction of his theory, and which he continued to stick to for the rest of his life (lasted edited by him in 1952 three years before he died in 1955), he is, I believe, in his theoretical construction, in this theoretical construction, basing the Lorentz transformations on the relativity of simultaneity (as well as saying this is what he is doing in his 1916 paper). But, you are right, there are lots of different papers out there, and if you want to pull quotes from them and say he is really overall, or more prominently, or more generally, constructing his theory in other way, if you make your case based on his other writings, then we can debate. “That “every inertial frame of reference has its own particular time”? That's a conclusion of the Lorentz transform, which is derived from the invariant c postulate.” If you believe that the way he constructed his theory in his book is not his main and final constructed form of his theory, but rather, there a better way to say that his theory is constructed, then, yes, and I’d love to see your outline of how he constructed his theory. But, if you believe that the final and main form of his theory can be found in his 1916 book, then at the end of the “Two Lightning Bolt Strikes” thought expedient he concludes with “We thus arrive at the important result: Events which are simultaneous with reference to the embankment are not simultaneous with respect to the train and vice versa (relativity of simultaneity). Every reference-body (co-ordinate system) has its own particular time; unless we told the reference-body to which the statement of time refers, there is not meaning in the statement of the time of an event.” (pp. 30-31) Now, to me, it seems clear that he believes he has just proven, via the “Two Lightning Bolt Strikes” thought experiment, that “events which are simultaneous in one inertial frame of reference are not simultaneous in another” [my paraphrase], and then, upon proven this, he then immediate makes the logical deduction “Every reference-body … has its own particular time.” I don’t believe that when he says “Every reference-body … has its own particular time,” that he is expecting that the reader will realize that he is referring to his 1905 proof; especially sense he does not refer to it. It seems to me he is doing something very different here than he did in 1905. And it seems to me what he is doing here is proving “events which are simultaneous in one inertial frame of reference are not in another” on page 31 and this using this, implicitly, as a justification of the premises of the Lorentz transformations on page 34. But, again, I agree, if you go through all of his papers, you can make the case that he constructed his theory otherwise. “and who are you to say this wouldn't be intuitive for anyone but yourself” When people first come to studying the Theory of Relativity, whether that is a brilliant young sixth grader who will eventually go onto to get a Ph.D. in this field, I believe he and all of the rest of us first come to this theory with the common sense ideas that simultaneous events and length and time do not change if you are in motion relative to them. If you believe that some people, before studying the Theory of Relativity, have the “common sense” notion that “events which hare simultaneous in one inertial frame of reference are not in another” then okay, you must hang with a different crowd of people than I do. And so, only for my crowd then and not yours, is this counterintuitive and so must be justified. --------------- To pzkpfw: “We've been over that. This is where I give up” Well, you could make the argument that since the two lightning bolt strikes do occur in the embankment and since they do occur “at the same time” Einstein is stipulating that the two lightning bolt strikes occur simultaneous in the embankment frame while leaving whether they are or are not simultaneous in the train frame, at this point in the thought experiment, unknown or undetermined. (I don’t remember you making this argument, but if you did, I’m sorry.) However, if this this your argument, you then make the additional argument (in my opinion of your argument) that Einstein then reasons that since the two men are at two different points when the flashes of light reach them, then logic dictates, that if they are simultaneous for the man on the embankment then they are not simultaneous for the man in the train. At no point in Einstein’s language can I find him making (can I read into it him making ) the argument that “logic then dictates that the other man must see the one flash of light before the other because he will be at a different point than the man on the embankment when the flashes of light reach him” (or anything to that effect)). What I see Einstein doing is saying the man in the train is actually in motion and the man on the embankment is actually at rest. “Now in reality (considered with reference to the railway embankment) he is hastening towards the beam of light coming from B, while he is riding ahead of the beam of light coming from A” (p. 30); which is beyond any of the most flexible and open-minded aspect of my logic to see as anything other than a statement, by Einstein, of motion, and of who is and who is and who is not in actual motion. If you can read that statement quoted in another way that does not necessarily mean motion, then please let me know. And so, if by saying Einstein stipulates who sees the two flashes of light simultaneously and then logically deduces that the other man cannot see them simultaneously, this means also stipulating who is actually at rest and who is actually in motion, then this thought experiment is a test of absolute rest. (And this must be the case. For one man to see the two flashes of light at the same time, and given that they occurred at equal distances from him, then he cannot move. And for one man to see the one flash of light before the other, and given that they occurred at equal distances from him, then he must move. And so then we know who is actually in motion and who is actually at rest in this thought experiment. Thus absolute rest. And the only other way out of this logic is to assume the conclusion (which those who think that this thought experiment does not prove anything happily do), and so we end up with Einstein’s “Two Lightning Bolt Strikes” thought experiment does not prove “events which are simultaneous in one inertial frame of reference are not simultaneous in another” while Comstock’s “One Light Bulb On A Moving Car” thought experiment does prove “events which are simultaneous in one inertial frame of reference are not simultaneous in another” as was detailed out above). ------- To Le Repteux: Thank you. And if any of them take up the challenge to disprove that Comstock, unlike Einstein, proves “events which are simultaneous in one inertial frame of references are not in another” it will be interesting to see the kind of thinking that ensues when it is I critiquing their affirmative stance. -------- To studiot: “The point is that the lightning (along with everything else in the universe) is not in any frame at all.” When a bolt of lightning moves from a thunder cloud at rest relative to Earth (or, in other words, rotation along in the atmosphere along with the rotation of Earth) to the planet, it is in the inertial frame of reference of the Earth (ignoring the curved rotational aspects). It is moving from one object to another in one inertial frame of reference. It is only when, in Einstein’s thought experiment, the moving flashes of light are moving to objects that may be consider moving or not moving relative to the moving flashes light that the problems arise. -------------- To Le Repteux: “He only claims that the mind experiment in question does not explain the real observations that we make, not that the data from these observations are false.” Right. I have not questioned any of the empirical evidence that confirms this theory. I am only saying that I think there is a problem with the theory (specifically part of the theoretical structure) itself. ------- Thank you all! Cheers! - Christopher

If I may, let me restate my original position, but now with all of the comments, questions, and issues that have arisen in this thread in mind. One I believe that the Lorentz transformations are based on the relativity of simultaneity, because: 1. That is how Einstein does in fact construct his theory in his book “Relativity: The Special and General Theory.” (He works through the “Two Lightning Bolt Strikes” thought experiment, comes to its conclusion, and then moves onto the Lorentz transformations.) 2. This is how Einstein says he has constructed his theory in his paper “The Foundation of the General Theory of Relativity.” 3. And, the counterintuitive assumption of the Lorentz transformations (“every inertial frame of reference has its own particular time”) is justified by being the conclusion of the “Two Lightning Bolt Strikes” thought experiment. To believe that the Lorentz transformations are not based on the relativity of simultaneity, is to believe: 1. In his book he just randomly decides to talk about the relativity of simultaneity just before the Lorentz transformations. 2. In his paper his either misspeaks or there is some other interpretation of the meaning of “… there follow, in the well-known way, the relativity of simultaneity, the Lorentzian transformations …” than the plain meaning of the text. 3. And he lays out the Lorentz transformation with an unjustified counterintuitive assumption which could be justified it he had constructed his theory with the Lorentz transformations based on the relativity of simultaneity. Two The statement “events which are simultaneous in one inertial frame of reference are not simultaneous in another” is counterintuitive. It may seem intuitive to you 100 years post the Theory of Relativity. But, in the early 1900’s it was definitely counterintuitive and could not simply be asserted but rather had to be argued for and demonstrated. It had to be justified. I believe that if the statement “events which are simultaneous in one inertial frame of reference are not simultaneous in another” is not a premise of the “Two Lightning Bolt Strikes” thought experiment, then the “Two Lightning Bolt Strikes” thought experiment does not work. Einstein says the two men are both equal distances from the two flashes of light at the time of their occurrences. And Einstein stipulates that the two flashes of light occur at the same time. And then you will say to me “You say that they occur ‘at the same time’ but you don’t say in what inertial frame of reference.” And then I will say “At this point in this thought experiment the concept ‘events which are simultaneous in one inertial frame of reference are not simultaneous in another’ has not been established yet, and so even though the events do occur, as stipulated by Einstein, in the inertial frame of reference of the embankment, this is not relevant. The way a man (or woman) in the early 1900’s would have understood the idea ‘at the same time’ would simply be the common sense idea that they occurred ‘at the same time’ without any need to reference inertial frames of reference. It is once Einstein establishes ‘events which are simultaneous in one inertial frame of reference’ that he then logically deduces ‘every inertial frame of reference has its own particular time.’ At this point in this thought experiment neither of these two ideas have been established yet. It is the purpose of this thought experiment to establish this, and so, by definition, this has not yet been established at the start of the thought experiment.” And then you will say to me “You don’t understand what you are talking about.” And then I will say “Okay let us agree to disagree.” I believe Einstein does not take “events which are simultaneous in one inertial frame of reference are not simultaneous in another and therefore every inertial frame of reference has its own particular time” as a premise of this thought experiment. There is no place in his text where he says he is doing this. I believe he is laying out his thought experiment with the early 1900 common sense understanding of “at the same time” which, at this point in the construction of his theory, does not include “every inertial frame of reference has its own particular time.” And so, if he is doing what I believe he is doing, with the two flashes of light occurring at the same time and at equal distances from the man on the embankment and traveling at equal velocities to the man on the embankment, the man on the embankment will see the two flashes of light at the same time. And so, if he is doing what I believe he is doing, with the two flashes of light occurring at the same time and at equal distances from the man on the train and traveling at equal velocities to the man on the train, the man on the train will see the two flashes of light at the same time. And so, the conclusion “events which are simultaneous in one inertial frame of reference are not simultaneous in another” does not follow. The thought experiment, if Einstein is doing what I believe he is doing, does not work. Now, if he is using “events which are simultaneous in one inertial frame of reference are not simultaneous in other” as a premise of this thought experiment, then it does work. However, this then means using the conclusion of this thought experiment as its premise. And I do not believe that Einstein used the conclusion of his thought experiment as its premise. And, lastly, it has been suggested in this thread that Einstein does not use his conclusion as his premise but rather that Einstein says that “the two flashes of light will either be simultaneous for the man on the train or for the man on the embankment, and I, Einstein, assert that if one man sees them simultaneous then it then logically deduced that the other man will see one before the other.” There is no point in this text where he says this is his argument. There is no point in this text where he implies this is his argument. To say that this is what Einstein is saying is, I believe, to read into his words something that is not there. The closest you can get to arguably finding him saying this is in the statement “We thus arrive at the important result: Events which are simultaneous with reference to the embankment are not simultaneous with respect to the train and vice versa (relativity of simultaneity.” (pp. 30 – 31). But this particular statement is, these particular set of words make up, the conclusion of the “Two Lightning Bolt Strikes” thought experiment. If Einstein is making the argument that “the two flashes of light will either be simultaneous for the man on the train or for the man on the embankment, and I, Einstein, assert that if one man sees them simultaneous then it then logically deduced that the other man will see one before the other” why would he only make this argument (if he is making this argument) in the latter half of his conclusory statement and in most obscure langue where it has to be read in that this argument is there (if it is there)? If Einstein is making the argument that “the two flashes of light will either be simultaneous for the man on the train or for the man on the embankment, and I, Einstein, assert that if one man sees them simultaneous then it then logically deduced that the other man will see one before the other” then this is pretty central to his overall argument and you would think he would take the time (as he does will all of the other various aspects of the “Two Lightning Bolt Strikes” thought experiment) to make this explicit (or even somewhat more implicit). And so, I do not believe he is making this argument. I believe this is reading in too much into his words and it is not there. When Einstein says “Now in reality (considered with reference to the railway embankment) he [the man on the train] is hastening towards the beam of light coming from B, whilst he is riding on ahead of the beam of light coming from A” I believe he is saying what he is saying. I believe he is saying that the man on the train is in motion towards the one beam of light and is in motion away from the other beam of light. I don’t see him saying “from the perspective of the embankment at rest it appears that the man on the train is moving towards one flash of light and it appears that that the man on the train is moving away from the other flash of light.” I see him saying that it is the embankment that is actually at rest (“Now in reality”) and the man on the train who is actually in motion. Now you could say “no, this is the language, ‘Now in reality (considered with reference to the railway embankment),’ where we can read in that Einstein is making the argument ‘the two flashes of light will either be simultaneous for the man on the train or for the man on the embankment, and I, Einstein, assert that if one man sees them simultaneous then it then logically deduced that the other man will see one before the other.’” And I suppose I can see how you can see him saying “the two flashes of light will either be simultaneous for the man on the train or for the man on the embankment,” but the latter half of that argument “and I, Einstein, assert that if one man sees them simultaneous then it then logically deduced that the other man will see one before the other,” I believe, can in no way be read into this language here. I believe he is saying what he is saying. He is saying that the man on the embankment is the one actually at rest and he is saying that it is the man on the train who is actually in motion. He says “Now in reality (considered with reference to the railway embankment) he [the man on the train] is hastening towards the beam of light coming from B, whilst he is riding on ahead of the beam of light coming from A.” He is saying that physically (in the sense of a thought experiment) the two flashes of light are moving towards the man on the embankment and physically (in the sense of a thought experiment) the man on the train is moving towards one flash of light while moving away from the other flash of light (while they also move towards him). He is not saying this only appears to be happening from the perspective of the embankment at rest. He is saying, these are his words, no reading in alternative meanings necessary, “he is hastening towards” and “he is riding on ahead.” To say that Einstein is saying that the man in the train “is moving” in these two phrases is to use alternative words but is in keeping with the plain meaning of the plain language and is not to read in an alternative meaning. However, what this means is, if (as it has been suggested in this thread) that Einstein stipulates for which person the two flashes of light are simultaneous (and in this case he just happens to choose the person on the embankment) and then by logical deduction the other man must see the one flash of light before the other, then by stipulating for which man the two flashes of light are simultaneous, this then becomes a test of absolute rest, because the other man does not just appear to be in motion from the perspective of man stipulated to see the two flashes of light simultaneous (and so also, by implication, is stipulated to be “at rest”) but rather “Now in reality…” “… he is hastening towards …” and “… he is riding on ahead …,” in other words he is the one actually physically moving (in the sense of a thought experiment) towards one beam of light and away from the other while the other man is the one actually physically at rest and having the two flashes of light move towards him. This is a test of absolute rest. If this is what Einstein is intentionally proposing (which I do not believe he is) then he has proposed a test of absolute rest. I simply think he made a mistake. I believe he was just accidentally thinking in terms of the man in the train as actually in motion and the man on the embankment as actually at rest, not consciously, but because the two flashes of light kind of seem to be “in” the inertial frame of reference of the embankment and “less connected” to the inertial frame of reference of the train. If Einstein is making the argument (which I do not believe he is) “the two flashes of light will either be simultaneous for the man on the train or for the man on the embankment, and I, Einstein, assert that if one man sees them simultaneous then it then logically deduced that the other man will see one before the other” then along with his statements of “hastening towards” and “riding on ahead,” which explicitly indicate actual physical movement (in the sense of a thought experiment), then he is saying by stipulating which man sees the two flashes light simultaneously we have established absolute rest and who is actually in motion. Three In Comstock’s thought experiment (the “One Light Bulb On A Moving Car” thought experiment, there is no need to assume the conclusion (“events which are simultaneous in one inertial frame of reference are not simultaneous in another”), there is no need to read in additional arguments into what he plainly says, there is no need to stipulate who sees the two flashes of light simultaneously and who does not (the man in the car will see them reach the front and the rear of the car simultaneously and the man on the road will see the one reach the rear of the car first and then the other reach the front of the car later), there is no need for the mathematics of the Lorentz transformations or its ramifications of “length contraction” and “time dilation” (all of which assumes the relativity of simultaneity and so becomes circular), and there is no chance that Comstock, unlike Einstein, unwittingly proposed a test of absolute rest. I believe, given the four axioms, Comstock’s thought experiment works and proves (in the sense of a thought experiment) “events which are simultaneous in one inertial frame of reference are not simultaneous in another” from which it can then be logically deduced “every inertial frame of reference has its own particular time” which is then the justification for this as an assumption of the Lorentz transformations, while, I believe, Einstein’s thought experiment does not. And that is the restatement of my initial position based on the issues and ideas that have come up in this thread. Thank you. ----- To studiot: I thought I did answer all of your questions. The two lightning bolt strikes occur in the inertial frame of reference of the embankment. The two clouds (not explicitly mentioned but that can assumed to be there) are in the inertial frame of reference of the embankment. The two bursts of lighting that make their way from the two clouds to the two points along the embankment are in the inertial frame of reference of the embankment. The two point of impact along the embankment are in the inertial frame of reference of the embankment. And when the two flashes of light from the strikes then leave the points of impact and head towards the two men, they are moving away from two points that are in the inertial frame of reference of the embankment. However, I believe that this is all irrelevant. I believe that the motion of lack of motion of emanating sources of the light (the points of impact), which are at rest relative the man on the embankment and are in motion relative to the man on the train, is irrelevant. If the two lightning bolt strikes occurred “at the same time” then even though the sources of those flashes of light are in motion relative to the man on the train is irrelevant and so he will see the two flashes of light at the same time. And, I believe, that just because the emanating sources of these flashes of light are in the inertial frame of reference of the man on the embankment and not in the inertial frame of reference of the man on the train does not make these flashes of light (moving through the vacuum of space, as stipulated) “in” the inertial frame of reference of the embankment or somehow “more connect” to the man on the embankment than to the man on the train. And in terms of changing the thought experiment, there are, in every thought experiment, essential and nonessential elements. For example, the walls of the train are not essential. And, in fact, I believe they are harmful in these sense that they can be misleading. What makes two different inertial frames of references is relative motion and not physical barriers. And so, if I’m right and the walls of the train are not essential, then Einstein’s thought experiment could be changed so that the man is riding on a skateboard down a side walk and not inside a train. The logic should work the same. It’s relative motion that is essential and not the train walls. And in the same way, the embankment, I believe is irrelevant. What matters is that the two sources of light are in the same inertial frame of reference as one man and in a different inertial frame of reference as another man (and the two men both happen to be the same distance from the two flashes of light at the time they occur). I also think that the embankment while not only not essential to this thought experiment is also misleading. By having lightning bolts strike two point along the embankment it gives the impression that the two flashes of light are “in” and “connected to” the inertial frame of reference of the embankment. And they are not. The sources of these flashes of light are, but not the flashes of light themselves. And so I think using two light bulbs in free space to analysis the logic is better. It strips away, what I believe is, some of the misleading elements of this thought experiment. ---------- To pzkpfw: “And you are assuming they are simultaneous in both frames.” Yes. This thought experiment establishes that “events which are simultaneous in one inertial frame of reference are not simultaneous in another” and so when Einstein says the two lightning bolt strikes occur “at the same time” the conclusion of this thought experiment has not yet been demonstrated and so there is no reason to assume that if they “occur at the same time” that this would not be the case from the perspective of all inertial frames of reference. It hasn’t been established yet. That is what this thought experiment purports to establish at the end, in its conclusion. “He stipulates elsewhere that the flashes are simultaneous for the embankment observer.” Cool. Where? I have no problem admitted when I’m wrong. (I don’t like to be wrong, but I have no problem admitted it.) I have been over and over this theory for many years. You have just made the claim that he stipulates that the two flashes of light are simultaneous for the embankment observer somewhere else. Where? “If talking from the point of view of the embankment there's no mistake to consider the train as moving.” Except for the fact that if the train does not merely appear to be moving from the perspective of the embankment but is in fact physically in motion then this becomes a test of absolute rest. And it cannot be “mere appearance.” The man on the train must physically actually move towards one flash of light and he must physically actually move away from the other flash of light in order to encounter (perceive) the one flash of light before the other. And so, if two flashes of light being simultaneous in one inertial frame of references mean another body in another inertial frame of reference must actually be physically towards one flash of light and must actually be physically moving away from the other flash of light (which he must be doing if he is not to see the two flashes of light simultaneously in his own inertial frame of reference) then this is most definitely a test of absolute rest. “Sorry, but I think your interpretation is very poor. I think you are tryting to hard to get to some conclusion you prefer.” I cannot see how “hasting towards” and “riding on ahead” are not statements of “motion.” And by saying “Now in reality” he is also saying that the man in the train is actually physically moving towards one source of light and actually physically moving away from the other source of light. I believe that that is the plain meaning of the language and not something I’m reading into his words. “I really don't think you've stumbled on some mistake that 98 years of science has missed.” I’m not the only one. I’ve seen two essays on the internet where two other guys have figured out the same thing. And there was also a posting in a forum where a guy said “hey, I figured out a test for absolute rest” and then used Einstein’s thought experiment. (He was, then, subsequently shouted down and no one realized, what I believe, was that he had found Einstein mistake, but then made the mistake of not realizing it was a mistake.) And, a few years ago, I sent this argument to a guy with a Ph.D. who specialization is Relativity. I had sent him several of my “paradoxes.” He enjoyed them. And he was able to show me why I was wrong over and over again. And then, I decided to send him my argument about why the “Two Lightning Bolt Strikes” thought experiment was wrong. He essentially conceded the argument and said something to the effect of “that’s why I use the other thought experiment” and then essentially brushed this off as no big deal. (Which, of course, we disagreed about whether it was or was not a big deal.) And so, no, I am not the only one who has noticed his. And my guess is back in the days before the internet, over the last 100 years, there have been guys and gals here and there who have noticed this, and then for whatever reason (perhaps because they thought it was not big deal) just let it go. “(and in disagreement with Comstoicks result)” Comstock’s thought experiment concludes “events which are simultaneous in one inertial frame of reference are not simultaneous in another. Comstock’s thought experiment does not take as a premise “events which are simultaneous in one inertial frame of reference are not simultaneous in another.” The physical (in the sense of a thought experiment) set up of Comstock’s thought experiment, and given the four initial axioms, logically leads to “events which are simultaneous in one inertial frame of reference are not simultaneous in another.” This does not need to be stipulated to in order to then also reach this as the conclusion. “I do not see your interpretation of Einstein as rational” And if we’ve reached this point, then we really need to part ways. If we’ve reached this point then we probably cannot even “agree to disagree.” “"playing God" view.” I should never have mentioned “God.” I’m sorry. That was a mistake. What I was trying to say is that if both observers are equally positioned to see the two flashes of light simultaneously, but it must be stipulated who sees them simultaneously, then in the thought experiment, by being the one who gets to make that decision one is, in a sense, “playing God.” It is too loaded of a word. And I should not have used. And, besides, I was using it in a context where I now think I misunderstood you position. I thought you were saying both men were equally positioned to see the two flashes of light simultaneously and so we must stipulate who sees the two flashes of light simultaneously (“playing God). But now I think you’re saying something different. I now think your saying something more like “it must be stipulated for which of the two men the two flashes of light are simultaneous. In the initial set up to the thought experiment it could be simultaneous for either man. But in the real world it will be simultaneous for one man (and therefore not for the other). So in the make believe world of thought experiments, after the initial set it, it then must be stipulated who sees the two flashes of light simultaneously.” And, yes, then the “playing God” would go away. --------------- To swansont: Eddington’s starlight deflection test occurred three years after (1919) after Einstein published his book (1916). I believe that it is appropriate to talk about thought experiment and logic and not just empirical evidence. And I believe that, like all theoretical structures, it is not just one big mass of undifferentiated ideas, but that theoretical structures have a starting point (or a few starting points) which are then built upon. And in my reading of the Theory of Relativity, it seems clear to me that the starting point is the relativity and simultaneity, and then it gets built up from there. The Special Theory of Relativity can exists without the General Theory of Relativity, but the General Theory of Relativity cannot exist without the Special Theory of Relativity. This theory, like all theories, is not just one big undifferentiated mass of ideas. There is structure to it. And examining that theoretical structure (and not just the results of empirical tests), and determining whether or not the structure holds, I believe, is a task worth doing and time not wasted. ---- Thank you all! Cheers! - Christopher

To xytz: Okay. ------- To studio: “since information cannot travel faster than c” This is a true statement, and a proposition that I’ve run into many times in the past when I was trying to turn the logic of this theory back in on itself and into a “paradox.” However, this factor does not come into play when examining either the “Two Lightning Bolt Strikes” thought experiment or the “One Light Bulb On a Moving Car” thought experiment. So, I agree. “Firstly the lightning event is a chance event and by chance, happens just right for the experiment. Secondly matters can be confirmed at leisure post event.That is both the positions of the observers and strikes can be measured subsequently.” Yep. It is a stipulation of this thought experiment that the two lightning bolt strikes occur at the same time. No problem. “Now ask yourself where does the lightning come from?” If the “Two Lightning Bolt Strikes” thought experiment works, it should also work if we replace the “lightning bolt strikes” with “light bulbs.” And we can then say that there are two light bulbs that are resting alongside the train tracks, and they are an equal distance from both men when they are in position with one another, and we can stipulate that the two light bulbs flash at the same time. I think what leads to much confusion with this thought experiment has to do with lightning bolts striking points along the embankment. This gives the reader the sense that the flashes of light are then more connected to the inertial frame of reference of the embankment than the inertial frame of reference of the train. But they are not. If the motion (or lack of motion) of the emanating source of light is irrelevant to the velocity of light, then it does not matter that the flashes of light come from lightning striking points along the embankment that happen to be at rest (in the inertial frame of reference of the embankment) relative to the man on the embankment. This thought experiment (if it works) should also work if there are two men out in free space and two light bulbs also out in free space. One of the men is at rest relative to the two light bulbs, and the other man is moving (relativity) towards one light bulb and away (relativity) from the other. From the odd man’s perspective it is the two light bulbs and the other guy that is moving. And, then, if we stipulate that the two light bulbs flash at the same time (which I believe we can do in a thought experiment) then the odd man will see the two flashes of light simultaneously. The two light bulbs are an equal distance from him at the time of the flashes and so the flashes of light (from his perspective of being at rest) travel over equal distances at equal velocities. Their motion (relative to him) at the time of the flashes is irrelevant. And so (to finally get around and answer your question) the lightning bolts are in the inertial frame of reference of the embankment, and the lightning bolt strikes occur in the inertial frame of reference of the embankment, and the emanating sources of the two flashes of light (the two points of impact) are in the inertial frame of reference of the embankment. “Does it come from a universe moving alongside the train?” Yes, from the perspective of the train at rest. “Or does it come from the universe where the track is sited?” I’m not sure what this means. The track is at rest relative to the embankment. The tracks and the embankment are in the same inertial frame of reference. The man in the train moving along the tracks is in a different inertial frame of reference. “Or does it come from another universe altogether?” There is only one universe in this thought experiment. And in that universe there are two different inertial frames of reference: the embankment and the train. And in this thought experiment the lightning bolts and the strikes all are in and all occur in the inertial frame of reference of the embankment. “Using that answer I can explain Einstein's train experiment to you.” Cool. Thank you. ---------- To pzkpfw: “That setup and stipulations are no different really (in the sense of setupishness and stipulationity) than the Einstein version. The setup by comstock ensures the flashes are simultaneous in the car frame, and shows they won't be for the bystander. Einstein sets up the embankment frame to have simultaneous flashes and shows they won't be simultaneous for the other observer.” I disagree. In Comstock’s thought experiment the setup “ensures” the flashes are simultaneous in the car and “ensures” the flashes are simultaneous for the bystander. For the man on the road the one flash of light travels a shorter distance and the other flash of light travels a longer distance. And so, if as stipulated, both flashes of light travel, for the man on the road, at equal velocities, the one flash of light must reach the rear of the car first and the other flash of light must reach the front of the car later. There is no difference, in Comstock’s thought experiment, between the “thinking” going into the analysis for the man on the road and the man in the car; there is not an “ensuring” and then a “showing.” The difference does not come from two different kinds of analysis, but in the fact that the two men are in two different situations in specifically whether the two flashes of light travel equal or unequal distances. For the man where the two flashes of light travel equal distances, then they reach the front and the rear of the car at the same time. And for the man where the two flashes of light travel unequal distances, then they reach the front and the rear of the car one before the other. In Einstein’s “Two Lightning Bolt Strikes” thought experiment, both men are in equal positions to see the two flashes of light simultaneously. When Einstein says (on page 30) “Now in reality (considered with reference to the railway embankment) he [the man on the train] is hastening towards the beam of light coming from B, whilst he is riding on ahead of the beam of light coming from A” I see this not as him stipulating that the two flashes are simultaneous for the man on the embankment and therefore also logic dictates that sense the man on the train will be in a different position than the man on the embankment when the flashes of light reach him he therefore must see one before the other, but rather as Einstein making the mistake of thinking that it is the man on the train who is actually “in motion” and that the flashes of light are somehow “in” or “more connected to” the inertial frame of reference of the embankment. But I think your reading of this (and your different reading of this than mine) is justifiable. When Einstein says “now in reality … he is hastening towards … [and] … riding ahead” I see this as a clear sign that Einstein is thinking that the man on the train is the one “actually in motion.” If I understand your interpretation of this quote correctly then “now in reality … he is hastening towards … [and] … riding ahead” means “if we stipulate that the man on the embankment will see the two flashes of light simultaneously, then from the perspective of the embankment at rest it is the man on the train who is in motion, and so we can then say he is in motion, we can talk about him as being in motion, and we can then also stipulate or logically conclude that he must see the one flash of light before the other.” Einstein certain doesn’t directly say this, and, I think, it’s a bit too much to read all of this into his words. Even if I’m wrong, I hope you will agree that it is at least plausible to read Einstein’s argument as one in which he makes the mistake of believing that it is the man on the train who is “actually in motion.” And a simple reading of the text, I believe, points to not the more complicated reading into his words but to the fact that he just so happened to make a mistake. We all do. “Comstock set it up so the flashes will be simultaneous in the car frame, by placing the bulb in the centre of the car. Einstein stipulates the strikes to be simultaneous in the embankment frame. It's basically the same thing. The real point is - what now is the situation for the other frame?” Again, I disagree. Einstein says the two lightning bolt strikes occur at the same time. This means they could reach the man in the train simultaneously. In Comstock’s thought experiment there is no possibility for the man on the road to see the two flashes of light reach the front and the rear of the car simultaneously. Comstock’s thought experiment proves “events which are simultaneous in one inertial frame of reference are not simultaneous in another.” Comstock proves the RoS (as you guys like to abbreviate it). In Einstein’s thought experiment both the man in the train and the man on the embankment are equally positioned to see the two flashes of light simultaneously. You have made the argument that if the one man sees the two flashes of light simultaneously then logically the other man cannot (and you have made the argument that Einstein is also making this argument). And I disagree. I think that in the “Two Lighting Bolt Strikes” thought experiment, since each man is justified in thinking that he is at rest, then, given how this thought experiment is set up, both the man on the train and the man on the embankment will see the two flashes of light simultaneously. (Again, we are discussing a thought experiment here and not whether or not the real world works this way.) And, even if I’m wrong, I hope you will agree that I am, at least, making a plausible argument. I hope you will agree that given how Einstein set up his “Two Lightning Bolt Strikes” thought experiment that it is not totally irrational to think that it leads to both men seeing the two flashes of light at the same time (in the world of thought experiments). And, if you agree that I’m not being totally and completely irrational in what I think his thought experiment leads to, then I think you will have to agree that Einstein’s and Comstock’s thought experiment are not equally valid, because I would argue (and I think you would agree with me) that for someone to conclude that in Comstock’s thought experiment both the man on the road and the man in the car can (or might or may) see the two flashes of light simultaneously is totally and completely irrational. Yes? No? “Aside from you seeming to contradict yourself (because the end result is the same but you claim different interpretations) that's where the Comstock experiment falls down, it doesn't show the reciprical nature of the relativity of simultaneity very well.” When Einstein says “… and vice versa (relativity of simultaneity) …” again you and I disagree. I do not think that he is saying because it could be the man on the train or the man on the embankment who sees the two flashes of light simultaneously this demonstrates the reciprocal nature of simultaneity but I think he is just asserting the reciprocal nature of simultaneity because that can be logically deduced. If Einstein’s thought experiment works and (my interpretation of what he is claiming) it proves that the man on the embankment will see the two flashes of light simultaneously and the man in the train will see the one before the other, then the same thing could be done with two lightning bolts coming from two clouds in the train striking two point in the train, and so the same logic (if his logic is right, and in my interpretation of his logic) will show, if we were to do the thought experiment in the inverse, that the man on the train will see the two flashes of light simultaneously while the man on the embankment will see the one before the other. In the same way Comstock’s thought experiment does not set out to show the reciprocal nature of simultaneity but it easily deduced. Simply move the light bulb out of the car and place it on the road. You will set the same result (with the two flashes of light hitting two points along the road) at the same time for the man on the road and one before the other for the man in the car. Comstock does not directly mention the reciprocal nature of simultaneity but it only a hop, skip, and a jump away and I’m sure he would have said “yeah.” “I really don't see why you are so hung up on that claimed "ambiguity".” Yep. We may be reaching a point of “agreeing to disagree.” To me it is totally clear that the two thought experiments are different, and one is weaker, and one is most likely wrong (unless other things are read into it), and one is ambiguous in a way that the other is not. I do respect your thinking. And so perhaps we just need to agree to disagree and end it here. “Einstein does that better by having both of his observers equidistant from the strikes.” Right. I’m sure in 1916 Einstein was away of Comstock’s 1910 thought experiment, and I think Einstein probably thought that his was the better of the two thought experiments because his thought experiment does not rely on clocks and Comstock’s necessary does (and two different sets of two clocks in the two different inertial frames of reference). “Simultaneity” is defined differently in Comstock’s and Einstein’s thought experiments and Einstein called his definition “… the most natural definition of simultaneity ….” I agree with you that Einstein’s thought experiment has its advantages … if it worked. But I don’t think it works. And you and I have been round and round this disagree of ours again and again. “Given you seem to accept Comstocks result, why do you phrase this as "that occurred at the same time" without reference to which frame they occured at the same time in?” “Well, that's basically getting to be metaphysical rubbish. Strikes are either going to be simultaneous in a frame or not. There's no "God power" involved in looking at a case where two strikes were simultaneous in one frame and figuring out whether they were in another. No more than Comstock is "God" with his light bulb placement.” In Einstein’s thought experiment he says that the two flashes of light occur at the same time and they do so when they are an equal distance from the two men. This thought experiment concludes (proves) that “events which are simultaneous in one inertial frame of reference are not in another.” If we don’t take this conclusion as also its premise then when examining this thought experiment “pre conclusion” it does not matter what inertial frame of reference these lightning bolt strikes come from. If we say, no, it does matter which frame of reference these lightning bolt strikes come from because “events which are simultaneous in one inertial frame of reference are not simultaneous in another” must be taken into account when determining whether or not in this thought experiment the man on the embankment and/or the man on the train will see the two flashes of light simultaneously or not, is then to use the conclusion of this thought experiment as one of its premises and this is circular logic. When using Comstock’s thought experiment there is no need to use the conclusion of the thought experiment, “events which are simultaneous in one inertial frame of reference are not simultaneous in another,” as a premise in order to prove that “events which are simultaneous in one inertial frame of reference are not simultaneous in another.” And so, if we are not using this as a premise, and if both men in Einstein’s thought experiment as it is set up are equally positioned to see the two flashes of light simultaneously, then if we are going to make the argument that, no, both men will not see the two flashes of light simultaneously but rather only one will and then we will logically reason that the other man will not, then, when analyzing Einstein’s thought experiment we are playing “God” is choosing one man over the other (and so would have to be the case in the real physical world). Now, if you saying that in this thought experiment we are not playing “God” in choosing one man over the other because the two lightning bolt strikes occurred in the inertial frame of reference of the embankment and so he will see them simultaneously, then I think you are making the same mistake as Einstein. The motion or lack of motion of the emanating sources of the flashes of light (the points of impact) is irrelevant. And once those flashes of light are in motion they are no more connected to the inertial frame of reference of the embankment than they are to the inertial frame of reference of the train. And if all we have done is stipulate that they occurred at the same time, then the man on the train is equally positioned to see them simultaneously and so to say one man or the other is the one who sees them simultaneously (and then argue that logic dictates then so the other man does not) is to become “metaphorically nonsensical” but to actually do this. “You continue to assume that simultaneous events must be simultaneous in all frames.” I assume this because before this thought experiment reaches its conclusion we have no reason to think otherwise. All we know at this point is what Einstein has stipulated and assumed. And before we reach the conclusion of this thought experiment he has stipulated that the two flashes of light occur at the same time. And so, without any reason to believe otherwise, yes, it is assumed that they are simultaneous for everyone. It is only after he reaches his conclusion of this thought experiment and proves (or believes he proves) that “events which are simultaneous in one inertial frame of reference are not simultaneous in another and therefore every inertial frame of reference has its own particular time” that we can then start talking about different inertial frames of references with events not being simultaneous in both and, in more general, different inertial frames of reference each having their own particular time (as is then assumed by the Lorentz transformations, which follow RoS). Again, in Comstock’s thought experiment the conclusion does not need to be assumed as a premise. ---- To swansont: “owing to length contraction” On page 30 of his book Einstein concludes: “We thus arrive at the important result: Events which are simultaneous with reference to the embankment are not simultaneous with respect to the train …” And he does this without a single reference to “length contraction” (or “time dilation” or the math of the Lorentz transformations). It is clear that Einstein believes he has proven this without reference to “length contraction.” And, I would argue (I have argued) that to use “length contraction” when analyzing this thought experiment, which is a ramification of the Lorentz transformations and the Lorentz transformations assume “every inertial frame of reference has its own particular time,” which is also the conclusion of this thought experiment, is to then engage in circular logic. I believe Einstein’s “Two Lightning Bolt Strikes” thought experiment must stand on itself own and apart from the rest of the theory which assumes “every inertial frame of reference has its own particular time” in order to prove that “every inertial frame of reference has its own particular time.” ------- To Dekan: “If we can work out the answers by doing "Thought Experiments" , why bother with any actual physical tests?” Thought experiments are useful, but so are empirical test. They are different. And while a thought experiment may be correct in the sense that given its premises it proves what it purports to prove its always possible that the premises are wrong or that the actual physical world is counterintuitive and so while the reasoning is right the world still doesn’t work that way. And To Janus: Yep. --------- To studiot: “This thread is going nowhere at approximately 0.99999999999c because no one seems to want to stick to the point and complete discussion of the first proposed 'experiment', rather prefering to introduce alternative experiments. Comstocks experiment or Einsteins? I could just as easily observe that Einstein introduced the formula E = mc2 in 1905, some 24 years after JJ Thompson introduced the formula E = 0.75melmc2” Yep. ----------- To Le Repteux: Maybe someday. --------- Thank you all. Cheers! - Christopher

xyzt said: “Good, Continue to waste your time. I am through trying to educate you.” You and I totally disagree. I believe that to try to disprove myself (or anyone else) is not a waste of time. Every day I ask the question over and over again “Do I know what I think I know.” And apparently you don’t believe in this same approach to life. That’s cool. ---- swansont said: “On must ask where an observer is when each bolt strikes, and where that observer is when the light reaches him/her, and that depends on the presence of relative motion. If the bolts do not travel the same distance, then the strikes can't be observed to be simultaneous.” This is the crux of the issue. If the man on the train is correct in thinking he is at rest (as Einstein says he is), then this observer [the man on the train] is at the midpoint between the two sources of light when they flashed and he will remain at this point and so he will see them simultaneously; because the two flashes of light have traveled the same distances at the same velocity to him. And so, in this thought experiment, if both men are correct in thinking that they are the one at rest (which Einstein says they are) then they will both see the two flashes of light simultaneously. And so, this thought experiment does not prove that “events which are simultaneous in one inertial frame of reference are not simultaneous in another.” (But Comstock’s does.) “It's not. The premise is that SR is correct. The investigation is whether events are simultaneous, but the status is not assumed.” When I read the book “Relativity: The Special and General Theory” it is clear to me that Einstein is building up the Theory of Relativity proof by proof and all resting on the initial proof of “the relativity of simultaneity.” But that’s just my impression of what he is doing. However, in the same year he published this book for the masses, 1916, he also published a scholarly article for the elite (not me) titled “The Foundation of the General Theory of Relativity.” And the third paragraph reads as follows: “Thus the special theory of relativity does not depart from classical mechanics through the postulate of relativity, but through the postulate of the constancy of the velocity of light in vacuo, from which, in combination with the special principle of relativity, there follow, in the well-known way, the relativity of simultaneity, the Lorentzian transformation, and the related laws for the behavior of moving bodies and clocks.” (see A. Einstein, "Die Grundlage der allgemeinen Relativitatsheorie," Annalen der Physik, 49, 1916.) (Please note, the “principle of relativity” is not the same thing as the “theory of relativity” and the former is explained in chapter 5 of his book.) In his book he builds his theory, proof by proof, based on the initial proof of the “Two Lightning Bolt Strikes” thought experiment. Not on the Lorentz transformations or anything else. He does this, but he does not actually come out and say “I’m build my theory on the “Two Lighting Bolt Strikes” thought experiment proving the “Relativity of Simultaneity.”” But, in that same year, 1916, in a different publication he does come out say this is what he is doing. In that quote is saying that the Special Theory of Relativity rests on two postulates: 1. The constancy of the velocity of light, and 2. The special principle of relativity And then he says “… there follow, in the well-known way …” He is saying what comes next in his theoretical structure of proof based proof and what he fist lists (after laying out the postulates) is: “the relativity of simultaneity” and then immediately after this (just does he does in his book) he lists: “the Lorentzian transformations” and then (again just as he does in his book) the ramifications of the Lorentz transformations “and the related laws for the behavior of moving bodies and clocks” (ie, “length contraction” and “time dilation”) And so you and I disagree. I think it is circular logic, when investigating whether or not the flashes of light are simultaneous, to take “events which are simultaneous in one inertial frame of reference are not in another” as a premise. I do not believe Einstein used this as a premise. I think he thought he made his case without this as a premise (as Comstock six years earlier had done). Thank you. -------- To studiot: I do want to have a wider discussion (not just about all of the Special Theory of Relativity, but also about the General Theory of Relativity). But, I was wrong in thinking that it would be totally obvious that the “Two Lighting Bolt Strikes” thought experiment does not work and we could more quickly move onto other things. But, I don’t mind. We can spend as much time on just this one aspect of this theory, on just this one thought experiment, for as long as is needed. Okay. In five lines? 1. Einstein says (and I agree with him) that the man on the train can consider himself to be at rest. 2. Einstein stipulates that the two flashes of light occur at the same time and at the same distance from the man on the train. 3. The motion, or lack of motion, of the emanating sources of the flashes light (the points of impact) are irrelevant. 4. And so, with the two flashes of light occurring (as stipulated) at the same time and then traveling at equal velocities over equal distances to the man on the train (who is justifiably “at rest”) he will then see the two flashes of light at the same time. 5. And so, this thought experiment does not prove that the man on the embankment will see the two flashes of light at the same time while the man on the train will see the one flash of light before the other. And if I’m allowed one more line (and, here again, I’m repeating myself but it seems somewhat necessary): 6. It is the conclusion of this thought experiment that “events which are simultaneous in one inertial frame of reference are not simultaneous in another and therefore every inertial frame of reference has its own particular time” and to address my five lines above by saying that this is not just the conclusion of this thought experiment but also a premise, I believe, is to engage in circular logic. Thank you. -------- To pzkpfw: In 1910 D.F. Comstock proposed the “One Light Bulb in a Moving Car” thought experiment. Given these four axioms: One. There is no absolute rest. Two. The velocity of light is independent of the motion of the emanating source. Three. The velocity of light is invariant for all observers. Four. The law of physics hold true (are the same) in all inertial frames of reference. This proves (in the sense of a thought experiment) “events which are simultaneous in one inertial frame of reference are not simultaneous in another.” Comstock proves the relativity of simultaneity. And this is done without the mathematics of the Lorentz transformations, this is done without any reference to “time dilation” or “length contraction,” and this is done without any ambiguity over for whom the two events are simultaneous and for whom one will occur before the other and therefore a stipulation is needed. The man in the car will see the two flashes of light reach the front and rear of the car simultaneously and the man on the road will see the one flash of light reach the rear of the car first and then the other flash of light reach the front of the car later. I believe Einstein, six year later, in his “Two Lightning Bolt Strikes” thought experiment, was attempting to prove the same thing Comstock proved in his “One Light Bulb In a Moving Car” thought experiment. And I believe he failed. I understand your argument. And while I don’t agree with you I must admit it is a plausible argument. When Einstein says “We shall show directly that the answer must be in the negative” (me quoting you quoting him) I believe he is saying that just as Comstock did show that the man in the car must see the two flashes of light reach the front and the rear of the car simultaneously and the man on the road must see the one flash of light reach the rear of the car first then the other flash of light reach the front of the car later, so too will he, Einstein, show in his “Two Lightning Bolt Strikes” thought experiment that the man on the embankment must see the two flashes of light simultaneously while the man on the train must see the one flash of light before the other. But, of course, I have to admit that your reading of his language is plausible. I have to admit that maybe Einstein is not attempting to do what Comstock did six years earlier. I have to admit that maybe Einstein is saying that it could be the man on the embankment or it could be the man on the train who see the two flashes of light simultaneously and then therefore logic dictates that since other guy is in a different position he can’t also see them simultaneously. Yep. Okay. So, then I have two question/comments for you. One. If Einstein is doing what you say he is doing, then, while his thought experiment does work, it is a much weaker thought experiment than Comstock’s. Comstock proves “events which are simultaneous in one inertial frame of reference are not simultaneous in another” without any ambiguity over who sees them simultaneously and who does not. If Einstein thought experiment works as you say it does, why use it and not the much stronger thought experiment that was well known at the time (1916) and that had been around for six years (since 1910)? Two. While “thought experiments” cannot “prove” what actually physically happens in the real world, they are supposed to “demonstrate” or “describe” what does happen in the real world. In other words, while the “Two Lightning Bolt Strikes” cannot “prove” that “events which are simultaneous in one inertial frame of reference are not simultaneous in another” is in fact what happens in the real physical world, it is intended to “show” that this is in fact what does happen in this real physical world. This thought experiment cannot “prove” this is true, but this thought experiment is saying essentially “yeah, this is how the real physical world does work.” Okay. If you agree with me so far, then here is my point: So, if in the real physical world there was a real physical man on a train and a real physical man on an embankment and there were two real physical flashes of light an equal distance from them that occurred at the same time, then (again, noting that this thought experiment did not prove anything) this thought experiment is telling us that one of the men will see the two flashes of light simultaneously while the other man will see the one flash of light before the other. Yes? And so, if you’re right and it’s a matter of stipulation about who sees them simultaneously and who sees one before the other, then in a sense we are playing “God.” In this thought experiment either you or I or Einstein steps in and says the man on the train or the man on the embankment is the one who sees them simultaneously. But, in the real physical world, you and I and Einstein, do not have this power. And so, if you and I agree that both the man on the embankment and the man on the train are equally positioned to see the two flashes of light at the same time, and if one of them does and the other does not, then in the real physical world, “God” must step in and take the place of you and I and Einstein and do the stipulating in the real physical world and decide who, the man on the train or the man on the embankment, sees the flashes of light simultaneously and who does not. But, in Comstock’s thought experiment there is no need for a “God.” In the world of thought experiments it is the man in the car who sees them reach the front and the rear of the car simultaneously and the man on the road who sees the one flash of light reach the rear of the car first and then the other flash of light reach the front of the car later. And if this same situation was to occur in the real physical world then then, while this thought experiment cannot prove this will happen, this thought experiment shows (or demonstrates) that this will happen in the real physical world without “God” having to step in an make the determination (stipulation). No? Thank you. ------ To Le Repteux: I’m not ignoring you, but as you can see my two hours of internet time at the public library is already taking up with a more basic discussion. What you are talking about, for me, is a much later discussion. Thank you. - Christopher (ps as always, sorry for the typos)

xytz said: “You aren't right, you are badly and profoundly wrong. Doesn't seem to stop you from posting the same errors over and over.” Okay. Let us say that the Lorentz transformations are not based on the “Two Lightning Bolt Strikes” thought experiment. Let us say that in his book for the popular masses such as myself, “Relativity: The Special and the General Theory,” Einstein is not building a theoretical structure brick by brick (proof by proof) but is rather taking the reader on a survey journey through several of the topics related to the Theory of Relativity. And let us say that he just happens to choose to talk about the “Relativity of Simultaneity” first just because he thinks that a reader of general knowledge and interest would find that interesting. And then after randomly talking about the “Relativity of Simultaneity” which concludes with “every inertial frame of reference has its own particular time” he then just randomly moves onto another topic related to the Theory of Relativity which just so happens to be the “Lorentz Transformations” which just so happen to have as one of their assumptions the counterintuitive idea that “every inertial frame of reference has its own particular time.” And let us say that it is all just a coincidence that he spends 33 pages setting up the “Two Lightning Bolt Strikes” thought experiment and concludes “every inertial frame of reference has its own particular time” and then immediate moves onto another random topic for the general population of readers which just so happens to have this conclusions as one of its assumptions and this counterintuitive assumption just so happens to now be justified by the “Two Lightning Bolt Strikes” thought experiment. Okay. Let us say this. That still doesn’t matter. If I come up with some mathematical formulas based, in part, on the assumption that “you can tell a person’s personality based on the lumps on their head,” and then some other guy, totally independent of me, comes up with a thought experiment that proves “you can tell a person’s personality based on the lumps on their head,” and then I use my math to examine that guy’s thought experiment, then, even though he and I originally worked independently, I am engaged in circular logic. I am using math that assumes the conclusion of the thought experiment that I am now examining. Even if I am wrong and Einstein did not construct his theory with the Lorentz transformations “based on” or “justified by” the “Two Lightning Bolt Strikes” thought experiment, that still does not change the facts that, one, the math of the Lorentz Transformations assumes “every inertial frame of reference has its own particular time,” and, two, the conclusion of the “Two Lightning Bolt Strikes” thought experiment is “every inertial frame of reference has its own particular time,” and so, three, to use this math to examine this thought experiment is to examine something already assumed and so is to engage in circular logic. No? Please do advise. Thank you. ---- studiod said: “Note I have not said any are wrong or right, just offered to discuss whether they are necessary or the best group of assumptions. Do you wish to listen as well as preach?” Cool. I hope you are getting the impression of me that I am not just hear to preach my “controversial” or “suspect” ideas about the Theory of Relativity. I have already admitted where I think my language, and ideas, have fallen short; based on what you have pointed out. And I have publically made the appropriate changes. If you believe that I need to make more changes to the first section of my first post in the thread, then please let me know. If I agree with you I will make the changes. If I disagree I will tell you why and we can discuss. I did not intend to come here to preach, but I seem to be doing a lot of that. I came here to lay out what I thought was a very clear piece of logic that showed that Einstein’s thought experiment needs to be replaced with Comstock’s. And, as you can see, at first I thought this idea was so obvious I didn’t think I needed to even respond to anyone. (And then when all the hate came pouring down I was ready to run, until challenged by the person I’m not allowed to directly address suggested that I go back and look at the previous responses, to which I did, and then I found myself unwittingly responding and “preaching.”) I hope you can see that I am willing to listen. I have made several corrections based on your and other people’s comments. Thank you. ------ To Le Repteux: There is something to what you said that I agree with, but for the most part I think we do not agree. And I’d love to debate you about what is the exact nature of “light.” But, right now, I have enough work to do in debating over whether Einstein’s “Two Lighting Bolt Strikes” thought experiment works and specifically right now over whether it is circular logic to use the Lorentz transformations to examine this thought experiment. Thank you. ---------- xyzt said: “Relativity is a non-contradictory theory. Only cranks who misinterpret relativity claim that they have found "contradictions".” As I’m sure you might suspect of someone such as myself, I spent years trying to turn the logic of the Special and General Theories of Relativity back on themselves and into a paradox. That is how I learned this theory. And, now, I understand that once you accept the premises it is an internally consistent theory. And so, if you assume “every inertial frame of reference has its own particular time” and then examine the “Two Lightning Bolt Strikes” thought experiment, then, yes, this thought experiment leads to the conclusion “every inertial frame of reference has its own particular time.” But I don’t believe that Einstein made this assumption (certainly not explicitly and I don’t believe even implicitly) when he laid out this thought experiment and analyzed it in the first 10 chapters of his book. I do not believe that Einstein concluded that “every inertial frame of reference has its own particular time” based on the assumption that “every inertial frame of reference has its own particular time.” Thank you. ---------- To pzkpfw: In the “twin paradox” the problem arises in that from both perspectives the other twin should not age while the observing twin does age. And this cannot be. But this “paradox” is resolved in that the experiences of the two twins are not the same. The twin in the space ship experiences acceleration and deceleration which are pseudo gravitational fields and so time goes more slowly. And the twin in the space ship shifts from one world line to another and so (as shown by the space time diagrams) skips over a big chunk of time that the twin remaining on Earth experiences. And so, the “paradox” is resolved and it is the twin on the space ship who does not age. If you are saying (and if you are saying that Einstein is saying) that in the “Two Lightning Bolt Strikes” thought experiment it could either be the man on the embankment who sees the two flashes of light simultaneously or the man on the man on the train who sees the two flashes of light simultaneously, then (I believe) you are then in the same position as those who initially proposed the “twin paradox.” I don’t think that it is enough to just say (to just stipulate) that the man on the train will see the two flashes of light simultaneously or to just say (to just stipulate) that the man on the embankment will see the two flashes of light simultaneously. This seems to be the major disagree between you and I. I think that if both the man on the train and the man on the embankment are in positions to see the two flashes of light simultaneously then (in this thought experiment) they will both see the two flashes of light simultaneously. I think to make your argument that one will see the two flashes of light simultaneously while the other will see one flash of light before the other, you need to make an argument (similar to that made in the “twin paradox”) as to why either the man on the embankment or the man on the train is preferred to see the two flashes of light simultaneously over the other. The fact that the two lightning bolt strikes occurred in the inertial frame of reference of the embankment does not give “preference” of simultaneity to the man in the inertial frame of reference of the embankment. Einstein stipulates that the air above the embankment has been removed. And so, after the strikes occurred, the flashes of light are moving through the vacuum of space and so as they travel to the two men they are no more connected to the inertial frame of reference of the embankment as they are connected to the inertial frame of reference of the train. And so, if it is stipulated (as it is) that they occurred simultaneously (as it is) and if they travel at equal velocities over equal distances (which they do) and if the man on the train is justified in considering himself to be at rest (which he is) then the two flashes of light will reach him at the same time. There is no reason, I can see, to prefer one man over the other (as is found in the “twin paradox”) when it comes to who will see the two flashes of light simultaneously. The fact that the sources of the flashes of light (the points of impact) are in one guys inertial frame of reference and not in the other guys inertial frame of reference, I believe, is irrelevant. I believe that the motion or lack of motion (from the perspective of each other observer) of the sources of the flashes of light (the points of impact) is irrelevant when examining this thought experiment. And again, any reference to “events which are simultaneous in one inertial frame of reference are not simultaneous in another and so given that the strikes are stipulated to be simultaneous in the embankment frame of reference means that they are not simultaneous in the train frame of reference” is to engage in circular logic as it is the conclusion of this thought experiment that “events which are simultaneous in one inertial frame of reference are not simultaneous in another” and so the conclusion should not also be used as a premise. Please advise. Thank you. - Christopher

To studiot: “So yes it is true but it is not a fundamental assumption of relativity.” Okay. I get it. I was wrong. I’m sorry. I misspoke. 1. The statement “There is no absolute rest” is less of an “assumption” and more of a “logical deduction.” 2. The statement “The velocity of light is independent of the motion of the emanating source” should be classified, as you point out, as more of something like a “principle” than an “assumption.” 3. However, the statement “The velocity of light is invariant for all observers” is still, as far as I know, an “assumption” because, as far as I know, this has yet to be empirically demonstrated. (Michelson-Morley does not demonstrate this.) And so, in the first section of my first post in this thread it should instead read: The Special Theory of Relativity is resting on four logical deductions, principles, and assumptions (relevant to this discussion): One. There is no absolute rest. Two. The velocity of light is independent of the motion of the emanating source. Three. The velocity of light is invariant for all observers. Four. The law of physics hold true (are the same) in all inertial frames of reference. However, logical deductions, principles, and assumptions could all be called “axioms.” (As xytz tried to correct me on earlier, but I guess I didn’t listen.) And so, in the first section of my first post in this thread it should instead read: The Special Theory of Relativity is resting on four axioms (relevant to this discussion): One. There is no absolute rest. Two. The velocity of light is independent of the motion of the emanating source. Three. The velocity of light is invariant for all observers. Four. The law of physics hold true (are the same) in all inertial frames of reference. And, since I’m really only talking about part of the Special Theory and not the whole thing, instead, it really should read: The “Two Lightning Bolt Strikes Thought Experiment” is resting on four axioms (relevant to this discussion): One. There is no absolute rest. Two. The velocity of light is independent of the motion of the emanating source. Three. The velocity of light is invariant for all observers. Four. The law of physics hold true (are the same) in all inertial frames of reference. Thank you for helping me make my language more precise. Now, has the first section of my original post been vetted enough in that it is now sufficiently precise enough to move onto the next section and discuss whether the “Two Lightning Bolt Strikes Thought Experiment” works as a thought experiment? Thank you. ---- To pzkpfw: If I understand your argument correctly, then you are saying: One: In the “Two Lightning Bolt Strikes Thought Experiment” it is set up so that it may either be the man on the train or the man on the embankment that sees the two flashes of light simultaneously, However, Two: Logic dictates that since the two men are in two different places relative to the sources of those lights when they perceive them, then if one man sees them simultaneously then the other man must see one before the other, And, Three: Einstein stipulates that the two flashes of light are simultaneous for the man on the embankment, And so, Four: The man on the embankment will see the two flashes of light simultaneously while the man on the train will see the one flash of light before the other. Am I close to understanding you? If this is your argument, it is correct on its face. However, this is not the argument Einstein is making. Einstein is not saying that either the man on the embankment or the man on the train may see the two flashes of light simultaneously. And its just that we stipulate that the man on the embankment sees the two flashes of light at the same time. And then, based on the logical argument that both men can’t see the two flashes at the same time and given our stipulation, we then therefore arrive at the conclusion that the man on the train sees one flash of light before the other. Einstein clearly believes that his thought experiment, as it is, leads to the conclusion that the man on the embankment will see the two flashes of light simultaneously while the man on the train will see one before the other and this thought experiment does this without saying something to the effect of “and the only reason why we know the man on the train sees the one flash of light before the other is because logic dictates that both men cannot see the two flashes of light simultaneously and we stipulated that the man on the embankment sees the two flashes of light simultaneously.” He believes based on his set up alone, he demonstrates that the two flashes of light will be perceived by the man on the embankment simultaneously and the man on the train will see the one flash of light before the other, and not based on us stipulating one or the other man [the man on the train or the man on the embankment] as the one who sees the two flashes of light simultaneously. (And, of course, I agree with you that if one man or the other may see the two flashes of light simultaneously while the other man then cannot see them simultaneously then this is not a test of absolute rest.) Thank you. ------------ To robinpike: “Obviously, the 'moving' observer is going to see the flash of light first.” Are you saying that it is the man on the train who is actually in motion and the man on the embankment who is actually at rest? Or, are you saying that it could either be the man on the embankment or the man on the train who is in motion and whichever one is in motion is going to see one flash before the other? I think this thought experiment leads to the idea that since neither man is in motion, from his own perspective, that both men will see the two flashes of light simultaneously. pzkpfw is more along the line of one of the two men will see the two flashes of light simultaneously, we just don’t which one until we stipulate which one, and then logic dictates that the other man is the one in motion and so he will see the one flash of light before the other. If you think that one of these two men must be in motion, then I think you agree more with pzkpfw than me. “The explanation would seem to require a mention of how length as well as time is perceived?” In the first ten chapters of his book where he lays out and concludes what he does in the “Two Lightning Bolt Strikes” thought experiment, he defines what length and time are for the purposes of this thought experiment. They are what you would intuitively expect: measuring rods and clocks. It is only after he has proven (or after he believes he has proven) that “events which are simultaneously in one inertial frame of reference are not simultaneous in another inertial frame of reference and therefore every inertial frame of reference has its own particular time” and so justifying an assumption of the Lorentz transformations and so then finding the ramifications of the Lorentz transformations of “time is slower between inertial frames of reference, and from both perspectives” and “length in the direction of motion is shorter between inertial frames of reference, and from both perspectives” and so leading to all the weird length and time ideas that flow from the Theory of Relativity. But, at the point of the “Two Lightning Bolt Strikes” thought experiment, Einstein defines “length” and “time” and he does so in the common sense way you’d expect these concepts to be defined (pre Lorentz transformations). Thank you. ----------- To studiot: “In this second system the coordinates of the same two points are given by the Lorenz transformation of the coordinates in the first system.” I have no idea if your math is correct or not. Maybe someday I take the hard plunge and learn the math. However, in the context of the “Two Lightning Bolt Strikes” thought experiment we are pre math. Whether or not the man on the embankment will see the two flashes of light simultaneously, while the man on the train will see the one flash of light before the other, does not depend on numbers. And it certainly does not depend on the numbers found in the Lorentz transformations. The Lorentz transformations rest of establishment of “every inertial frame of reference has its own particular time” and this is established (or attempted to be established) through the “Two Lightning Bolt Strikes” thought experiment, and so to explain the results of the “Two Lightning Bolt Strikes” thought experiment via the mathematics of the Lorentz transformations would be to engage in circular logic. ------------ To xytz: “So, you made a whole bunch of false statements and you come back with "I mis-spoke".” If I’m standing on my floor I can say “My body is resting on the floor” and I can say “My body is resting on my feet.” The first statement makes perfect sense. The second statement also makes perfect sense to us because we intuitively understand that the words “my body” actually to mean “the rest of my body other than my feet” because my feet which are part of “my body” are not resting on themselves. And so while the second statement makes sense, in a technical sense it is also wrong. I said that the “Special Theory of Relativity is resting on the Two Lighting Bolt Strikes thought experiment.” In the same way that the statement “My body is resting on my feet” is technically wrong, then so am I here in this statement about Special Relativity. However, what I said is essentially or basically true in the same way that the statement “My body is resting on my feet” is essentially or basically true. I believe that me just coming out straight forward and saying that “I was wrong” and “I misspoke” and not trying to argue that “while my was technically wrong it was essentially or basically right” in the same way that saying “My body is resting on my feet” is technically wrong while essentially right was being gracious and was an attempt to avoid another tangential line of argument in this thread that I would then need to address. I understand that it is part of the Internet culture, and specifically the forum culture, to never admit to a mistake, and if you do then you are open to having that admission highlighted with the implication that if you admitted to a mistake in at one time then the rest of what you have said should be suspect. But, of course, I disagree. And so, in the last section of my first post in this thread it should be corrected to read: The General Theory of Relativity is resting [in part] on the Special Theory of Relativity and the [main body of the] Special Theory of Relativity is resting on its [initial] two lightning bolt strikes thought experiment and the two lightning bolt strikes thought experiment is false. The foundation of this theoretical structure must be revised. (see Comstock, D.F. (1910), “The Principle of Relativity”, Science 31 (803): 767–772) Thank you for helping me make my language more precise. And I don’t believe the diction between “subsumes” or “rest” matters. If you think so fine. I don’t. And if you do believe that such a distinction between these two terms and concepts does matter then please show me why. If I agree with you I will correct my language. And if I don’t agree with you I will tell you why and we can discuss. “I already did. Here it is again. The Lorentz transforms tie the time of the observer on the platform to the time of the observer on the train:” On page 30 of his book Einstein writes: “We thus arrive at the important result: Events which are simultaneous with reference to the embankment are not simultaneous with respect to the train and vice versa (relativity of simultaneity). Every reference-body (co-ordinate system has its own particular time; unless we are told the reference-body to which the statement of time refers, there is no meaning in a statement of the time of an event.” And he does so without any claim to have only arrived at this conclusion based on the mathematics of the Lorentz transformations. He believes he arrives at this conclusion based on the four implicit and explicit axioms found contextually as he spells out the “Two Lightning Bolt Strikes” thought experiment. And I argue (and others in the forum have told me that I’m wrong) that this thought experiment is the bases of the Lorentz transformations (in that it is then what makes the counterintuitive assumption of the Lorentz transformations that every inertial frame of reference has its own particular time then a reasonable assumption), and if I’m right, then to use the math of the Lorentz transformations to prove that the “Two Lighting Bolt Strikes” thought experiment works is then to engage in circular logic (in using something assuming the conclusion as then also the premise of the same thought experiment). Thank you. - Christopher

Thank you for the responses. --- pzkpfw wrote: “Another is that events occurring at a single location (which equates to "an observer") will be agreed on by all (to be simultaneous or not). For example, two cars drive into a stop sign at the same time. There is no observer (whether standing "still" by the pole or "flying by" at Mach 3) who will think one car hit the sign first - there'd be no pole remaining for the other car to hit, and all observers will agree if both cars hit the pole.” I believe you are talking about the general area of non-synchronized clocks between inertial frames of reference. So, for example, in Comstock’s thought experiment both the man in the car and the man in the road will agree that the two flashes of light reach the clocks in the car at the front and the rear of the car at the same time. And, in fact, if these clocks had light sensitive switches where they mechanical hands were frozen at a particular reading when the flashes of light reach them, they would have to show the same time otherwise there would be a paradox and this theory would either, one, show that we live in a paradoxical world, or, two, then be shown to be false. I believe you are saying the same thing with the cars and pole example you use. No? The non-synchronization of clocks comes much later in this theoretical structure. In fact, I don’t believe it is addressed in Einstein’s book, but it is definitely today part of the theory. If I’m right it arouse as a consequence of the Space-time diagrams. However, it definitely comes after the Lorentz transformations and the establishment of length contraction and time dilation. What I am talking about is the thought experiment that comes before these transformations and the establishment that “events which are simultaneous in one inertial frame of reference are not simultaneous in another” as true (as far as thought experiments go) so that this counterintuitive assumption of the Lorentz transformations is not simply suspect. “So if the flashes were simultaneous in the embankment frame and the equidistant embankment observer sees them at the same time, will the train observer see them at the same time? No. Because he is moving, according to the embankment observer, and light travels at a finite speed, one flash must reach the train observer before the other. And the train observer won't disagree; the flashes can't reach him at the same time in one frame, and at different times in another frame.” If this is right, then this becomes a test of absolute rest; if we can in fact say that it is the man on the train who is moving (“Because he is moving …”). Or, if this is right, then the two flashes of light moving through the vacuum of space (as Einstein stipulates in his thought experiment) are somehow more connected to the inertial frame of reference than to the inertial frame of reference of the train. This could be perhaps argued is the case because the flashes of light originated from two points in the inertial frame of reference of the embankment. But this would be a totally new theory in physics are relativity. Right now, the understanding is that the motion of the emanating source of light is independent of the velocity of that light (and this applies to the man in the train). “The flashes can be simultaneous in either (or neither) relatively-moving observers frame, but can't be simultaneous in both frames.” This may or may not be true. I understand your argument. (There is the possibility that light travels towards all things, but that is a much, much more complicated and a much, much later and not appropriate here argument.) However, even if you are right, this does not shore up Einstein’s two lightning bolt strikes thought experiment. You are making a different argument. (And, again, you may be right and so maybe instead of replacing Einstein’s argument with Comstock’s we can replace it with yours.) Einstein does not say that maybe the guy on the embankment sees both of the flashes at the same time while the guy on the train sees one flash of light before the other or maybe the guy on the train sees both flashes of light at the same time while the guy on the embankment sees one flash before the other, we just don’t know (sort of in line with the same kind of thinking in the “twin paradox”). He does not say this. He says: “Hence the observer [the man on the train] will see the beam of light emitted from B earlier than he will see that emitted from A.” (p. 30) So, while I respect your reasoning, I don’t think it leads to shoring up Einstein’s two lightning bolt strikes thought experiment. Both the man on the embankment and the man on the train are in equal positions to see the two flashes of light at the same time, but Einstein says that it is the man on the train (and not the man on the embankment) who does and will see one flash of light before the other. And if I’ve missed and/or overlooked any of your important points, please let me know. Thank you. ----- phildukephd wrote: “It may be I am missing something here, but don't the Michaelson- Morley experimental results show Einstein's theory re different frameworks is correct?” Michelson-Morley does not involve different frames of reference. The observers and the beams of light were all in the same inertial frame of reference at all times. “And of course there are many more tests made via modern technology that confirm Einstein's thnking.” Yes. I hope I don’t come across as disputing this. Yes, there are lots of various empirical physical tests confirming both the Special and the General Theories of Relativity. “I believe in the value of thought experiments, but their experimental confirmation is very desirable. and eventually absolutely necessary. I suggest that a hypothesis that cannot be tested remains of little value until it is tested.” I have also posted in this thread a proposed empirical physical test of the initial assumptions that “the velocity of light is invariable for all observers;” which, if my limited research is correct, has not yet been directly tested. Please let me know if I’ve missed anything. Thank you. -------- studio said: “Although your posts are long enough to be sermons, you appear to be seeking a rational discussion.” I was criticized for not addressing all of the points being made against me. I did not think they were relevant to showing (or even addressing) that Einstein was wrong … specifically … when he concluded based on the two lightning bolts strikes thought experiment that “events which are simultaneous relative to the embankment are not simultaneous relative to the train.” And now that I am taking the time to address each criticism/critique … well now … “That means that none of your three assumptions above are available.” All theories rest on assumptions. All of Physics rests on the assumption that “the physical world exists.” Rene Descartes and David Hume have shown us that this cannot be “know.” And therefore when dealing with Physics we must “assume” this. And that’s fine. Assumptions are everywhere. If we got hung up on only dealing with things not based on assumptions we’d end up saying nothing more than Descartes did in “I think, therefore I am,” and then now saying nothing more than Hume did in “Thought exits.” Of course the Special Theory of Relativity rests on the assumption “There is no absolute rest.” None of what Einstein said would make sense if we thought “well maybe there is absolute rest.” Of course the Special Theory of Relativity rests on the assumption “The velocity of light is independent of the motion of the emanating source.” None of what Einstein said would make we thought “maybe the velocity of light depends of the velocity of the emanating source.” Of course the Special Theory of Relativity rests on the assumption “The velocity of light is invariant for all observers.” None of what Einstein said would make sense if we thought “well maybe the velocity of light depends on the motion of the observer.” And while he does not just come straight out and list these three assumptions in a row, they all can be contextually found in the first ten chapters of his book. (And, I’m sorry, but I’m too tired from this “sermon” to flip around the pages and pull out quotes. But they are all there.) “The guiding principle is a sort of conservation principle (but not a conservation law as in the conservation of energy) which can be phrased that we want (assume) that the laws of physics are such that they work out the same in all reference systems” As xyzt pointed out earlier, I have made mistakes by summarizing (glossing over) things. In addition to the three assumptions I listed I could have included others (such as “The Special Theory of Relativity rests on the assumption that the physical world exists” and “The Special Theory of Relativity rests on the assumptions that not only does the physical world exits but it is knowable” and so on.) And I could have included the “assumption” that “the laws of physics are the same for all inertial frames of reference.” And, now that I think about it, I was wrong. I didn’t include this assumption because I didn’t think it was relevant to the point I was making (that the two flashes of light thought experiment does not work). But, now I think I should have included it. I’m sorry about that. In my first post in this thread I should have written: The Special Theory of Relativity is resting on four assumptions (relevant to this discussion): One. There is no absolute rest. Two. The velocity of light is independent of the motion of the emanating source. Three. The velocity of light is invariant for all observers. Four. The law of physics hold true (are the same) in all inertial frames of reference. However, I do not agree with you that the three assumptions that I listed are not assumptions of this theory. This theory would make no sense without them. And while I do not agree that the three assumptions that I listed need to be thrown out and replaced with the one assumption you listed, I do agree with you that I was wrong for not listing this assumption. Thank you. And please let me know if I’ve missed anything. --- Thank you. - Christopher (PS: Sorry for the typos that are inevitably all over the place in here.)

(I only have two hours of internet time at the public library, and I made a lot of typos rushing through that long response yesterday.) And one big one was: “I’m saying that thought experiments are equivalent to empirical physical evidence.” I meant to say the opposite: “I’m [not] saying that thought experiments are equivalent to empirical physical evidence.” To DimaMazin: Thank you for offering to send me your math, but I am totally unqualified to analyze it. I understand the concepts of the Special and General Theories of Relativity, but not the math. And I know that some people say that the Theory of Relativity is all math based, and therefore I am opening myself up to the comment that I shouldn’t be saying anything about this theory or he concepts contained within it if I don’t understand the math. But, oh well. Such a comment still would not show that “the man on the embankment will see the two flashes of light at the same time while the man on the train will see the one flash of light before the other.” Thank you for your offer. Cheers! - Christopher

I have reread the entire thread. Strange said: 1. “We already know that times and distances are observer dependent and not necessarily the same for all observers. The thought experiment you are referring to (and making a bit of a hash of) is intended to demontrate that the concept of "at the same time" is also not the same for all observers. So if you say "at the same time" you need to specify which frame of reference this is in (I think that if you go back to Einstein's orginal description, you will find he does that). Similarly, you need to specify which frame of reference you are referring to when you say where the lightning strikes happen (again, I think you will find Einstein does this).” I disagree. The two lightning bolt strike flashes of light thought experiment is not merely meant to “demonstrate something already known” but rather to “demonstrate this is true.” How did we already know that times and distances are observer dependent before it was demonstrated? It had to, at some point, be first demonstrated. Michelson-Morley does not demonstrate this. 2. “This contradicts what you previously said. This has nothing to do with the movement (or otherwise) of the source. It is purely that the man on the train is moving towards (and away from) the place where the lightning strike happened. As you previously said.” Yes. I set up the thought experiment as Einstein did and then walked to the conclusion that Einstein did. And then I went back and showed why this was false. Yes. I am saying the way Einstein laid out the logic is incorrect. So, yes, I contradict my summarization of his logic, because it needs to be. - And, no, the man on the train is not moving towards the two flashes of light. If so, then this is a test of absolute rest. If there is no absolute rest then the man on the train can just as easily be considered as being at rest. And it is the flashes of light that are moving towards him. Einstein states that the air above the embankment has been removed. And so once the lightning bolt strikes occur the are no more connected to the inertial frame of reference of the embankment as they are to the inertial frame of reference of the train. From the perspective of the man on the train at rest (which Einstein says he is justified in believing) the two flashes of light come from two moving sources (the points of impact) from equal distances (as Einstein sets up this thought experiment to include) and at equal velocities. And so, the man on the train will see the two flashes of light simultaneously. 3. “Of course it isn't. This is a thought experiment, therefore it cannot prove or disprove anything. It is purely a teaching aid (failed in this case, apparently).” One of the assumptions of the Lorentz transformations is that each inertial frame of reference has its own “time.” This is counterintuitive. And, so, how is Einstein justified is in making this counterintuitive assumption? Because before the lays out the Lorentz Transformations in Chapter 11 he spends the first 10 chapters and first 33 pages of his book in laboriously laying out this thought experiment and proving that “events which are simultaneous in one inertial frame of reference are not simultaneous in another and therefore every inertial frame of reference has its own particular time.” To quote him directly from pages 30 and 31: “We thus arrive at the important result: Events which are simultaneous with reference to the embankment are not simultaneous with respect to the train and vice versa (relativity of simultaneity). Every reference-bot (co-ordinate system) has its own particular time …” If he’s not “proving” this “result” then why is it important? He is “proving” or “demonstrating” or “showing” or whatever word you want to use that this is true. But he is wrong. The two flashes of light thought experiment does not “demonstrate” that events that are simultaneous in one inertial frame of reference are not simultaneous in another. Both the man on the embankment and the man on the train will see the two flashes of light at the same time. The two flashes of light thought experiment does not “show” that events that are simultaneous in one inertial frame of reference are not simultaneous in another. Both the man on the embankment and the man on the train will see the two flashes of light at the same time. When I use the word “prove” when talking about this thought experiment I am not saying that this “proves” that this is how the physical world actually works. I’m saying that thought experiments are equivalent to empirical physical evidence. But, yes, you can “prove” (or “demonstrate” or “show”) things are true with thought experiments … in the world of thought experiments. And that is what Einstein is doing. He is “demonstrating” or “showing” that “events that are simultaneous in one inertial frame of reference are not simultaneous in another” based on the two lightning bolt strikes thought experiment. He is not proving this is empirically physically true, but rather is it showing that it is true based on the premises of this thought experiment in the world of thought experiments. But he is wrong. Both the man on the embankment and the man on the train will both see the two flashes of light at the same time. 4. “I also don't get why you think your failure to understand something means that a very well-tested and practically useful theory should be wrong.” Whether or not the physical world works according the ideas laid out in the Special and General Theories of Relativity is totally separate from whether or not the two lightning bolt strikes thought experiment works. Someone can be wrong, but still get it right. I am not questioning whether or not there are many, many tests that confirm the predictions of the Special and General Theories of Relativity. What I am point out is that the two flashes of light thought experiment does not work. 5. “This pedagogical example is not intended to prove anything, merely to explain it.” I totally disagree. For him to lay out the Lorentz Transformations with the implicit assumption that “every inertial frame of reference has its own particular time” is to lay out a counterintuitive assumption. And I suppose there is no rule against counterintuitive premises, but one should not. However, if one can “demonstrate” that a counterintuitive assumption is actually correct, then all the better. And, again, he takes 10 Chapters and 33 pages to do this. But, again, his logic is flawed in this first 10 chapters and first 33 pages. Both men will see the two flashes of light at the same time. --- xyzt said: 1. “False, GR subsumes SR, it does not "rest on SR"” “Subsumes” or “rests” I don’t care. The point is that you don’t get to the theory of General Relativity without the theory of Special Relativity. One of the foundations of General Relativity is the thought experiment showing that acceleration and gravitation are equivalent (and later modified so say just so on a “local” level). And this is separate and independent of Special Relativity. But the General Theory of Relativity also rests on the idea that because in a spinning disk the outer edges move faster than the inner portions to another body at rest to the spinning disk and so, given the conclusions of the Special Theory of Relativity, the clocks at the edge of this disk will run more slowly than clocks at the center of the disk and (quoting from page 90): “Thus o our circular dis, or, to make the case more general, in every gravitational field, a clock will go more quickly or les quickly, according to the position in which the clock is situated (at rest).” You need the Special Theory of Relativity to get to the General Theory of Relativity, and, before all that, you need first show that “events which are simultaneous in one inertial frame of reference are not simultaneous in another inertial frame of reference” so be able to make the counterintuitive claim that “all inertial frames of reference have their own particular time” without simply asserting something counterintuitive as true. 2. “False. SR rests on a set of axioms. Relativity of simultaneity is a CONSEQUENCE of those axioms.” Yes. I agree. I misspoke. I was summarizing. I am sorry. However, what this simply means is that after accepting the axioms of the Special Theory of Relativity the first part of that theory reasoned out (the two flashes of light thought experiment leading to the conclusion “events which are simultaneous in one inertial frame of reference are not simultaneous in another inertial frame of reference”) is incorrect. And, so, it is not what the Special Theory of Relativity is actually resting on that needs to be replaced with Comstock’s thought experiment, but rather the first part of the Special Theory of Relativity, that then the rest of the Lorentz Transformations and the rest of the Special Theory of relativity is resting on, that needs to be replaced. I misspoke. I will try to be more precise in the futurre. 3. “False. You simply misunderstand the thought experiment. In addition, thought experiments cannot be used to disprove (falsify) a theory, only real experiments can do that. As an aside, RoS is not testable. There is some debate about this issue in the philosophical (not physical circles) but the bottom line is that it isn't testable.” Please show me why the man on the embankment will see the two flashes of light simultaneously while the man on the train will see one before the other. Please show why I misunderstand this thought experiment. And, again, I’m not talking about the actual physical world. I am talking about whether or not this thought experiment works as a thought experiment in “showing” what it purports to show: that events which are simultaneous with respect to the embankment are not simultaneous with respect to the train. ---- Strange said: “1. Thinking that you can prove or disprove anything with a thought experiment. 2. Thinking that your misunderstanding of a thought experiment has any significance. 3. Thinking that the theory is based on relativity of simultaneity 4. Thinking that your misunderstandings of a popular science book trump experimental evidence. 5. Oh, I give up. Like all the rest, you will just ignore all attempts at explanation and assume you know best. Good luck. ” You and I disagree. I think that in the world of thought experiments you can prove things with thought experiments. Why did Einstein take 33 pages to “show” “demonstrate” that “events which are simultaneous with respect to the embankment are not simultaneous with respect to the train” and call this an “important result” (page 30) if he was just “illustrating” something and not “proving” something in the world of thought experiments? I do believe that this theory is based on the relativity of simultaneity. If this was not “established” (“proved”) first then the premises of the Lorentz transformations that “every inertial frame of reference has its own particular time” would simply be counterintuitive without anything to back it up and therefore suspect. Again, I am talking about Einstein’s argument about the two flashes of light in his book and not about experimental evidence or anything to do with the actual facts in the real world. I hope I don’t appear to be ignoring you now. But maybe so. It may appear that I’m just typing in a bunch of words while ignoring the merits of you critique of me. I hope not. All I can do is try. I cannot control your impression of me. ----- And so … Before the point in the thread where I was ready to give up, and I said no one had shown me that I was wrong but only told me that I was wrong, I still do not see where anyone had in fact shown me that I was wrong about Einstein’s thought experiment being wrong. I do not see here anyone showing me that “the man on embankment will see the two flashes of light at the same time while the man on the train will see the one flash of light before the other.” ---- To Janus: Thank you for taking up the challenge. “Now if we switch to the train frame, we have to stay true to these facts: The light from each strike reaches the train observer at different times and when he is next to different points of the embankment, and his camera will have recorded two pictures confirming this.” It sound to me like you are saying the same thing that Einstein said. He wrote (page 30): “Now in reality (considered with reference to the railway embankment) he is hastening towards the beam of light coming from B, whilst he is riding on ahead of the beam of light coming from A.” I think this is where he makes his mistake. He is thinking of the beams of light somehow being “in” or “more connected” to the inertial frame of reference of the embankment and “separate” and “independent” and “not connected, or less connected” to the inertial frame of reference of the train. I don’t think you can say that the one flash of light will reach the man on the train before the other. In fact, the embankment is totally unnecessary. If this thought experiment works then it could be two light bulbs rest in free space relative to one another man in free space. Then then there is a another lone man, from the perspective of the other three bodies, moving towards one light bulb and away from the other. But, from the perspective of the lone man, it is the other man and the two light bulbs that are in motion. And if it is stipulated that when the two light bulbs are an equal distance from the lone man and they flash at the same time (as it is in Einstein’s thought experiment) then the motion of the two light bulbs is irrelevant to the velocity at which the flashes of light travel to the man and so since they travel over equal distances the lone man will see the two flashes of light at the same time. The embankment is irrelevant. And if it is said that the lone man will see the one flash of light before the other because simultaneous events in one inertial frame of reference are not simultaneous in another, then we are back to circular logic as this thought experiment is meant to “demonstrate” or “show” or “prove” this conclusion (in the world of thought experiments). If you think I misunderstood the point you were making, please let me know. (The idea you bring up about each flash of light must pass the one man before the other man is very interesting. I’ve never thought about that before. But I don’t think that gets you to “events which are simultaneous in one inertial frame of reference are not simultaneous in another,” but rather perhaps to “events which are simultaneous in one inertial frame of reference are simultaneous in another, but from the perspective of both inertial frames of reference these same events are not simultaneous in the other inertial frame of reference” which is not what Einstein was going for. And, again, if we simply switch over to Comstock’s thought experiment we get to where Einstein was attempting to go.) I’m going to skip over your thought on length contraction for now. Length contraction comes after the Lorentz Transformations. Before the Lorentz Transformations Einstein simply asserts: “A priori it is by no means certain that this last measurement will supply us with the same result as the first. Thus the length of the train as measured from the embankment may be different from that obtained by measuring in the train itself.” (page 33). I have no problem with the Lorentz transformation and their conclusions once “events which are simultaneous in one inertial frame of reference are not simultaneous in another and therefore every inertial frame of reference has its own time” has been established, which Comstock’s thought experiment does and Einstein’s does not ... to my logic. Again, thank you for taking the challenge, and please let me know if I overlooked an important point in your response. Thank you. - Christopher

If by "classical" you mean that "the classic response of someone in denial is to say that you told me I was wrong while not showing me that I was wrong when in fact that person had been shown that he was wrong" then please show me where in this thread you showed that "the man on the embankment will see the two flashes of light at the same time while the man in the train will see the one flash of light before the other." Maybe I'm in such denial that that that logic is here in this thread but because I'm in such denial my eyes can't see it. Please show it to me. To say that I'm "classically" in denial is again to "tell" me that I'm wrong while not "showing" me that I'm wrong. Thank you. - Christopher

Okay. I tried. I give up. You believe that I am simply unreasonable. However, while many of you told me that I was wrong, not a single one of you showed me that I was wrong. And what I mean by that is if the two lightning bolt strikes thought experiment is so obviously right, then walk me through it. Show me why the man on the embankment will see the two flashes of light at the same time and the man on the train will see the one flash of light before the other. I don't think you can do it. And I don't think you can do it not because I'm someone who refuses to see reason, but because the logic is not there. So, okay, it's off to the Speculations folder. I lost. And I apologize to the moderator for addressing him directly, but it seemed appropriate. And I do thank you for just moving me to Speculations and not straight up deleting me. Thank you. - Christopher

To the moderator: Thank you for deleting my angry vent about the other forum deleting my post. It was bad form. And thank you for allowing the rest of my post to remain on your forum. I will try to be more proper in the future. (However, by then also leaving my response to my quote of them, it makes it sound like I’m saying “I don’t get it” to my own post.) To those who have taken the time to read my essay and respond: I understand that you think that I don‘t understand the Special and General Theories of Relativity. But, I don’t understand why. I never said that the two lightning bolt strikes thought experiment proves anything in the physical world. The philosophy of science teaches us that a theory can never be proven true but it can be proven false. If my theory is that every time I flip my coin it will come up heads, and if I flip it a billion times and it comes up heads every time, I have not proven my theory true but rather I have confirmed it to a high degree of likelihood, because on the one billion and one flip it could come up tails (and if it does then I have proven my theory false). However, in the world of thought you can prove things. If, given certain assumptions (or premises) you reason you way to a conclusion, and if you logic is right, then you have proven that conclusion (in the world of thought). My point is given the assumptions of the two lightning bolt strikes thought experiment (... and if I’m wrong about what the assumptions are then please specifically point out what the correct assumptions are ...) Einstein incorrectly then concludes that “events that are simultaneous in one inertial frame of reference are not simultaneous in another inertial frame of reference.” However, if you take those same assumptions and use them in Comstock’s thought experiment you can conclude “events that are simultaneous in one inertial frame of reference are not simultaneous in another inertial frame of reference.” This must be established in order to then say “each inertial frame of reference has its own particular time” as Einstein does. And this must be established in order to justify the Lorentz Transformation, and this must be established in order to then go on and on showing such things as “clocks synchronized in one inertial frame of reference are not synchronized in another” and so on and so on including the idea “clocks experiencing centrifugal force run more slowly the greater the centrifugal force and therefore in all gravitational fields clocks run more slowly the greater the gravitational force” and so on and so on. The Theory of Relativity is a set of proofs based on proofs. And the initial proof is that “events which are simultaneous in one inertial frame of reference are not simultaneous in another.” The two lightning bolt strikes thought experiment is not merely a pedagogical sideshow demonstration (and even if it was it still does not work). It is the initial proof that all of the other proofs are based on. I don’t mind being wrong. I don’t like it, but I don’t mind it. I understand that you guys all think that I am wrong. That is fine. But can you please specifically show where my logic is wrong. Thank you. - Christopher (PS: The discussion turned to how to test the Special Theory of Relativity. There are several tests of this theory: Michelson-Morley, Kennedy-Thorndike, Ives-Stilwell and so on. However, none of these test the assumption “the velocity of light is invariant for all observers.” I believe I have figured out how to do this. Again, thank you.) ----- Test of an Initial Assumption of the Special Theory of Relativity Send an electromagnetic wave to a satellite above Earth’s atmosphere and in the vacuum of space and not in synchronous motion with the rotation of the Earth. Then have that satellite relay the electromagnetic wave to another satellite in synchronous motion with the first satellite and also above Earth’s atmosphere and in the vacuum of space. And then have that second satellite return the electromagnetic wave back to Earth. And then do the same thing again but in the reverse direction. From the perspective of the Earth at rest, the two satellites are in motion and the electromagnetic wave relayed from one to the other will travel two different distances in the two different cases. The Special Theory of Relativity predicts that from the perspective of Earth in one case it will take a longer time for the wave to be returned to Earth and in the other case it will take a shorter time for the wave to be returned to Earth. As the satellites move they rotate relative to the Earth at rest. This rotation will make their linear motion increase and decrease. The linear motion of the satellite relaying the electromagnetic wave when it relays it and the linear motion of the other satellite when it receives the electromagnetic wave need to be the same for the flash of light to have moved between them in the same inertial frame of reference from the perspective of Earth. This can be done if the satellites are in the right positions. And it will be different depending on which way the flash of light is being relayed. (FN: Any bending of the wave as it is relayed from one satellite to the other due to gravity will need to be factored in.) If the two electromagnetic waves take two different amounts of time to return to planet Earth then the Special Theory of Relativity will again be confirmed, and if the two electromagnetic waves take the same amount of time to return to planet Earth then the Special Theory of Relativity will have been shown to be false. The variations in the atmosphere as the electromagnetic wave makes its way to and back from the satellites may make the results inconclusive. However, if this experiment were to be done over and over and over again a sufficiently large number of times then the individual skewed results would tend to balance out and the overall results would either tend towards the difference between the two cases as predicted by the Special Theory of Relativity or tend towards equal amounts of time in the two cases and so disprove the theory. There are several tests of the Special Theory of Relativity: Michelson-Morley, Kennedy-Thorndike, Ives-Stilwell and so on. None of these directly test what happens when a wave of light moves across a vacuum in one inertial frame of reference and the observer is in another inertial frame of reference. This is a direct test of the Special Theory of Relativity assumption of “the speed of light is invariable for all observers.” ----- Synchronized Clocks The above proposed test requires synchronized clocks. One method is to synchronize two clocks next to one another then slowly transport one of them to the other location very slowly. Due to time dilation this will cause them to become unsynchronized but only to a small degree. There is another way to synchronize two clocks at a distance. Start with four clocks; place one at one of the two locations and place three at the other location. Synchronize two of the nearby clocks. Then transport (quickly or slowly) one of them to the other stationary clock. Then synchronize those two clocks with the slightly out of sync time with the first clock. Then return the moved clock back to the first clock. Synchronize the fourth clock with the out of sync clock. Then return the clock that was already moved back to the other clock. The velocity at which the moved clock is moved each time must be the same and the three accelerations must be the same and the three decelerations must be the same. The time discrepancy between the first and the second clock is at much or less than the time discrepancy between the first and the fourth clock. And the time discrepancy between the second and the fourth clock is as much or less than the time discrepancy between the second and the third clock. If this is done carefully enough these should be equal amounts. The two processes are perfectly inversely symmetrical. If the second clock was behind the first clock 3/4 of the time difference between the first and fourth clocks then the fourth clock would be behind the second clock 3/4 of the time difference between the second and third clocks. But this would mean the time difference between the second and third clock would be greater than the time difference between the first and the fourth clocks. And given that the processes are perfectly inversely symmetrical this logically cannot be. For the time difference between the first and the fourth clock to be the same as the time difference between the second and third clocks the time difference between the first and the second clocks must be 1/2 the time difference between the first and the fourth clocks. And so, after doing this reset the second clock forward 1/2 of the time difference between the first and the fourth clocks and to a logical certainty (although maybe not to a practical one given how precise the moving can be done) they are synchronized. This actually could be done with fast moving clocks. The amount of discrepancy is unimportant. What is important is that the two processes are as perfectly inversely symmetrical as possible. (FN: This could be done repeatedly over and over again with any number of clocks to get an overall amount and reduce any biases in the actual physical process.)

----- The Special Theory of Relativity The Special Theory of Relativity is resting on three assumptions: One. There is no absolute rest. Two. The velocity of light is independent of the motion of the emanating source. Three. The velocity of light is invariant for all observers. ----- The Two Lightning Bolt Strikes Thought Experiment A man is sitting still on an embankment alongside a set of train tracks. He has two mirrors fashioned together in a v shape so he can see down the length of the train tracks in both directions at the same time. There is also man on a train. The train is moving down the tracks. He too has a v shaped set of mirrors that allow him to see down the length of the train tracks in both directions at the same time. When the man on the moving train reaches the point where the man on the embankment is sitting two lightning bolts strike two points along the train tracks at the same time. The two points where the lightning bolts strike are equal distances from the two men at the time of the strikes. After the lightning bolts strike the train tracks the man on the train continues to move. As the flashes of light move towards the two men the man on the train moves towards one flash of light and away from the other. With the distance between the man on the train and the one flash of light getting shorter and with the distance between the man on the train and the other flash of light getting longer, this means the man on the embankment will see the flashes of light simultaneously while the man on the train will see the flash of light he is moving towards before he sees the flash of light he moving away from. There is no known way to determine absolute rest. When two bodies are in motion relative to one another we cannot say which body is actually in motion and which body is actually at rest or if both are in motion and neither is at rest. And so it could be the train that is in motion or it could be the embankment that is in motion or both. The Special Theory of Relativity tells us that the man on the train will consider himself to be at rest and the embankment to be in motion. And the Special Theory of Relativity tells us that the man on the train will consider the distances the two flashes of light have traveled to be the equal distances they have traveled relative to the train. The Special Theory of Relativity also tells us that the man on the train will not see the one flash of light travel at a greater velocity towards him and the other flash of light travel at a lesser velocity towards him. He will see both flashes of light travel at the same velocity (300,000 km/sec). So, if the two flashes of light have traveled equal distances at equal velocities but one arrives before the other, then, for the man on the train, the lightning bolt strike he is relatively moving towards must have occurred first and the lightning bolt strike he is relatively moving away from must have occurred later. And so, Einstein concludes: “Events which are simultaneous with reference to the embankment are not simultaneous with respect to the train ....” The Special Theory of Relativity tells us that the velocity of light is independent of the motion of the emanating source. And so, for the man on the train, when the two lightning bolts strike the two points along the moving tracks and create the two flashes of light, the sources of these flashes of light (the points of impact) being in motion does not affect the velocity at which these flashes of light travel towards him. And so, in this thought experiment, given that the motion or lack of motion of the emanating source of the light is irrelevant, and given that it may be the man on the train who is at rest and embankment that is in motion, with the two flashes of light traveling at the same velocity over equal distances to the man on the train this means that the man on the train will see the two flashes of light at the same time. To say that the man on the embankment will see the two flashes of light at the same time while the man on the train will see one flash of light before the other, is to say that the man on the embankment is the one actually at rest and the man on the train is the one actually in motion; which we cannot. And to say that the man on the embankment will see the two flashes of light at the same time while the man on the train will see one flash of light before the other because “simultaneous events in one inertial frame of reference are not simultaneous in another inertial frame of reference” is a premise of this thought experiment and not just its conclusion is to engage in circular logic; which we should not. The fact that the lightning bolt strikes occur outside the train and the man in the train is in the train is irrelevant. This thought experiment could just as easily have been proposed with a man sliding along the frictionless train tracks just by himself. This thought experiment does not prove: “Events which are simultaneous with reference to the embankment are not simultaneous with respect to the train ....” The theoretical justification for the Special Theory of Relativity is the validity of this thought experiment. ----- Alternative Thought Experiment A different thought experiment was proposed by David Frost Comstock in 1910 (six years before Einstein proposed his two lightning bolt strikes thought experiment). Taking the premises of Einstein’s thought experiment and using them with Comstock’s thought experiment, it then does work. In this thought experiment there is one light bulb in the middle of a moving car. It flashes. One flash of light goes to the front of the car. And another flash of light goes to the rear of the car. From the perspective of the car at rest the man in the car will see the two flashes of light reach the front and the rear of the car simultaneously and from the perspective of the road at rest the man on the road will see the one flash of light reach the rear of the car first and then the other flash of light reach the front of the car later. And so, given the premises, this proves: “Events which are simultaneous with reference to the embankment [car] are not simultaneous with respect to the train [road]....” (FN: In his book Einstein takes some time to work out what he believes is the correct definition of “simultaneous” and he finds it in “If the observer perceives the two flashes of lightning at the same time, then they are simultaneous.” This alternative thought experiment does not prove that the flashes of light reaching the front and the back of the car are “simultaneous” for the man in the car in the way he defined this term. So, not only must the thought experiment be replaced with the alternative thought experiment but the definition of “simultaneous” must also be replaced. The definition he used does not apply here. In this thought experiment “simultaneous” cannot mean that identical clocks at the front and the rear of the car show the same time readings when the flashes of light reach them, because, if this theory is true, both the man in the car and the man on the road will say that the flashes of light reached the two clocks at identical time readings given the non-synchronization of clocks between inertial frames of reference. The man on the road has to measure the time the flashes of light reach the front and rear of the car based on synchronized clocks in his own inertial frame of reference. And so the man on the road would have to have two clocks: one at the point on the road corresponding to the rear of the car when the flash of light reaches it, and one at the point on the road corresponding to the front of the car when the other flash of light reaches it. The man in the car also has to have two clocks at the front and the rear of the car. And the definition of “simultaneous” is then identical time readings on these two clocks for each man in their own inertial frame of reference; which is the case for the man in the car and is not the case for the man on the road. And so in the revised statement “Events which are simultaneous with reference to the embankment [car] are not simultaneous with respect to the train [road]” the term “simultaneous” means something different than how Einstein defined it. It may be a trivial distinction but it should be noted.) The General Theory of Relativity is resting on the Special Theory of Relativity and the Special Theory of Relativity is resting on the two lightning bolt strikes thought experiment and the two lightning bolt strikes thought experiment is false. The foundation of this theoretical structure must be revised. (see Comstock, D.F. (1910), “The Principle of Relativity”, Science 31 (803): 767–772) ----- mod deletions ----- Frankly, I don’t mean to be rude, but I don’t get it. The point of the two flashes of light thought experiment is to show that “events which are simultaneous relative to the embankment are not simultaneous relative to the train.” I don’t understand what Physcisforums.com is saying about demonstrating assumptions not being justified. ? Is PF saying that the two lightning bolt strikes thought experiment is about “disproving an assumption” rather than proving something? Is PF saying that the thought experiment that the Special Theory of Relativity (and then the General Theory of Relativity) is resting on does not prove anything but rather “disproves an assumption”? Is PF saying that this whole elaborate theoretical structure is resting on a “disproved assumption”? No. The two lightning bolt strikes thought experiment is meant to prove that “events which are simultaneous in one inertial frame of reference are not simultaneous in another inertial frame of reference.” But it does not prove this. However, Comstock’s thought experiment does. Thank you. - Christopher (And, obviously, I should not have stepped away for two weeks.)

Another "Wedge Circle" and Brownian Motion Question --- side view / top down view A small solid is floating on the top of a liquid. It is contained within barrier walls. The barrier walls reside above the liquid and do not directly interact with the fluid. The shape of the barrier is a "wedge." There are three walls: a long wedged barrier wall, a short straight barrier wall, and a long straight barrier wall. There is a small opening at the narrow end of the wedge, and a small opening at the wide end of the wedge. The barrier walls are fixed in place and do not move relative to the container of fluid. This is all within a closed system. top down view The small floating solid is subject to Brownian Motion. It moves randomly. And, from time to time, it randomly collides with the barrier walls. When the small floating solid collides with the barrier walls, randomly over and over again, the overall angle of reflection is perpendicular to the angle of each wall. The overall angle of reflection from colliding with the long wedged barrier wall is slightly to the left. The overall angle of reflection from colliding with the short straight barrier wall is directly to the right. And the overall angle of reflection from colliding with the long straight barrier wall is neither more left nor more right. (There is also Brownian Motion within the small floating solid and within the solid barrier walls. These fluctuations will randomly make the angles of reflections greater and smaller than the angles of incidences by varying degrees. However, since these fluctuations are random, the probability is that there will be no overall net effect. The overall angle of reflection will be perpendicular to the angle of each barrier wall.) top down view There is an area around the small floating solid, within which, it will likely move to next. The specific place it will move to next within this area is random (with the exception that the small floating solid will more likely move a shorter rather than a longer distance). If the distance between the long wedged barrier wall and long straight barrier wall is within this area, then the reflections off of these walls will significantly interact with each other, and after reflecting off of one of these walls the small floating solid will either move out into the open space or it will cross the open space and collide with the other wall. top down view If the small floating solid moves out into the open space, and then comes to a stop, its next move will be random. However, with the long wedged barrier wall and the long straight barrier wall being within this area, the movement of the small floating solid will not be totally random. The trajectories of the overall reflections off of these walls crisscross with each other, and nudge the small floating solid more and more to the left in an overall zigzag pattern. (The actual path of the small floating solid will not strictly be a zigzag. The actual path of the small floating solid will be filled with random movements in all directions. However, overtime, the small floating solid will be nudged more and more to the left in an overall zigzag pattern.) If the small floating solid crosses the open space and collides with other wall, it will then be reflected off of the other wall. The overall angle of reflection off of the long wedged barrier wall is slightly to the left. So when the small floating solid reflects off of the long wedged barrier wall and then crosses the open space and collides with the long straight barrier wall, overall, the small floating solid will be moving slightly more to the left. And thus the overall angle of reflection off of the long straight barrier wall will no longer be neither more left nor more right. The overall angle of reflection off of the long straight barrier wall will be slightly left. And this will make the overall zigzag pattern slightly more pronounced to the left. (This more pronounced zigzag pattern also comes from the overall neither more left nor more right longer reflections off of the long straight barrier wall that cross the open space and collide and then reflect off of the angled long wedge barrier wall.) top down view When the small floating solid collides with the short straight barrier wall, randomly over and over again, the overall angle of reflection is directly to the right. At times, the small floating solid will be reflected directly out into the open area of the wedge just to the right of the short straight barrier wall. At other times, after being reflected off ofthe short straight barrier wall, it will collide first with another barrier wall before then being reflected out into the open area just to the right of the short straight barrier wall. Once in the open area of the wedge, the next movement of the small floating solid will be random. It can move left and collide again with the short straight barrier wall which will reflect it back to the right. It can move to another place within the open area. Or, it can collide with the long wedged barrier wall or long straight barrier wall, where the interaction between these two will start nudging it, overall, back to the left. top down view Due to the differences in the reflections from the collisions with the barrier walls and their interactions, the small floating solid will move overall to the left. Then, at some point, the probability is that it will exit the wedge barrier through the small opening on the left. top down view If there is an infinitely long line of connected wedge barriers fixed in place above an endless container of fluid, then the small floating solid will move overall to the left forever. One form of the Second Law of Thermodynamics is "No cycle is possible whose sole result is the abstraction of heat from a single reservoir and the performance of an equivalent amount of work." "Work" is forcetimes distance. When an object is set in motion "work" is done on that object. To move the small floating solid continuously overall to the left "work" must be done on the small floating solid. And the "work" done here comes from a single heat bath. --- top down view The wedge barrier can be curved around into a "wedge circle." The widest part of the wedge is closed off by a straight barrier wall. There is a small opening between the widest part of the wedge and the narrowest part of the wedge, making it an open circle. When the small floating solid collides with the outer wedged barrier wall, randomly over and over again, the overall angle of reflection is slightly counterclockwise. When the small floating solid collides withthe straight barrier wall, randomly over and over again, the overall angle of reflection is directly clockwise. And, when the small floating solid collides with the inner circular barrier wall, randomly over and over again, the overall angle of reflection is neither more counterclockwise nor more clockwise. top down view The trajectories of the overall reflections off of the outer wedged barrier wall and inner circular barrier wall crisscross with each other and an overall zigzag pattern will occur. This will nudge the small floating solid more and more counterclockwise. The longer overall counterclockwise reflections off of the outer wedged barrier wall that cross the open area and collide with the inner circularbarrier wall will make the overall reflections off of the inner circular barrier wall slightly more counterclockwise, and a more pronounced overall zigzag pattern counterclockwise will emerge. (This more pronounced zigzag pattern will also come from the overall neither more counterclockwise nor more clockwise longer reflections off of the inner circular barrier wall that cross the open space and collide and then reflect off of the angled outer wedged barrier wall.) After colliding with the straight barrier wall, at times, the small floating solid will be reflected directly clockwise out into the open space of the "wedge circle" just clockwise of the straight barrier wall. At other times, after colliding with the straight barrier wall, the small floating solid will collide first with another barrier wall before then being reflected out into the open space just clockwise of the straight barrier wall. Once in the open area just clockwise of the straight barrier wall the next movement of the small floating solid will be random. It can move counterclockwise and collide with the straight barrier wall again which will reflect it back clockwise. It can move to another place within the open area. Or, it can collide with the outer wedged barrier wall or inner circular barrier wall, where the interaction between these two will start nudging it, overall, back counterclockwise. top down view The small floating solid will move in an overall counterclockwise circular path. And then, at some point, the probability is that it will move counterclockwise through the small opening from the widest to the narrowest part of the wedge. The motion in an overall counterclockwise circular path will continue. And this process will continue forever. Just as "work" is done in moving the small floating solid leftward in the infinite line of connected straight wedge barriers, so to "work" is done in the "wedge circle" in moving the small floating solid counterclockwise over and over again. And, here too, this "work" comes from a single heat bath. If the small floating solid in the "wedge circle" is connected to a round, and very very light weight, magnet, and if this magnet is capable of rotating around a central axis, then this magnet will be rotated overall counterclockwise. And if a wire is placed perpendicular to the lines of magnetic flux, then a current will be created in the wire in one overall direction. And, in accordance with Lenz Law, when the magnet is creating a current in the wire the motion of the rotating magnet (and the connected small floating solid) will be slowed to equal the current created in the wire. The thermal energy of the fluid is turned into the kinetic energy of the small floating solid (and rotating magnet) and this is then turned an electrical current. Another form of the Second Law of Thermodynamics is "The entropy of a closed system cannot decrease with time." As long as there is thermal energy the small floating solid (and the magnet) will continue move overall counterclockwise, and more and more thermal energy will be turned into an electrical current. --- What are the Second Law implications of the "wedge circle?" --- 1. The Feynman Brownian Ratchet fails to produce rotation in one overall direction because larger and smaller fluctuations in Brownian Motion in the solid and fluid elements of the system push and retard the ratchet "forwards" and "backwards" equally. The question presented here involves a small floating solid having collisions with differently angled barrier walls. The Brownian Motion fluctuations in the solid elements here will make the angles of reflections greater and smaller than the angles of incidences to varying degrees, however, since these fluctuations are random, overall they will have no net effect. The "wedge circle" is not just another version of the Feynman Brownian Ratchet. 2. In the straight wedge barrier, the overall reflections near the corner between the short straight barrier wall and the long wedged barrier wall are largely perpendicular to each wall, even though each wall blocks the open area to one side of the other wall, since that also near the corner between the two walls there will be more reflections off of one wall that then reflect off the other. (And the same is true in the "wedge circle" with the reflections near the corner between the straight barrier wall and outer wedged barrier wall.) 3. There is an overall zigzag pattern that emerges between the short straight barrier wall and long wedged barrier wall in the straight wedge barrier, and between the straight barrier wall and outer wedged barrier wall in the "wedge circle." While moving the small floating solid away from the corner, the small floating solid is moved a little bit more rightward and a little bit more clockwise. While this slows the overall leftward motion and overall counterclockwise motion some, this does not change the overall effects. 4. The analysis is easier if the collisions are considered perfectly elastic. If less than perfectly elastic collisions occur, heat is generated (and the motion of the reflected small floating solid is slowed down). This heat is concentrated, at first, at the point of contact. It will then disperse out from there until it is evenly spread throughout the system. Considering less than perfectly elastic collisions complicates the analysis, but does not change, overall, the angle of reflection. Before the heat is evenly dispersed throughout the system, there will be a greater concentration of heat in the barrier wall, in barrier wall side of the small floating solid, and in the liquid around and beneath the barrier wall. This greater concentration of heat will mean more Brownian Motion activity on the barrier wall side of the small floating solid than on the other. This will push the small floating solid further away from the barrier wall but, overall, it will not change the angle of reflection. 5. The small floating solid does not need to move infinitely leftward or counterclockwise forever for "work" to be done. When Brownian Motion sets a small floating solid in motion, without the presence of barrier walls, in one random direction and then another, "work" is being done. Another form of the Second Law of Thermodynamics is "If a system undergoes spontaneous change, it will change in such a way that its Entropy will increase or, at best, remain constant." It is well known that when Brownian Motion sets a small floating solid in motion (or even when the random fluctuations of Brownian Motion lead to momentary decreases in Entropy within the fluid itself) that this formulation of the Second Law of Thermodynamics is temporarily violated. This is also true when the small floating solid is within the wedge barriers. However, when the small floating solid is within the wedge barriers and the motion of the small floating solid starts and stops and starts again, the overall path of that motion is predictable. There is a greater decrease in disorder when the small floating solid moves around within the wedge barriers than when it moves around without them. And there is a greater decrease in Entropy. 6. There is probably no need for the small floating solid, and the same effects could come from just a fluid in a "wedge circle" shaped container, but the overall movement of a mass of fluid, as opposed to the movement of a single floating solid, is much harder to conceptualize.

A "Wedge Circle" and Brownian Motion Question side view A small solid is floating on the top of a liquid. It is contained within barrier walls. The barrier walls reside above the liquid and do no directly interact with the fluid. The small floating solid is subject to Brownian Motion. It moves randomly. And, from time to time, it randomly collides with the barrier walls. top down view The shape of the barrier is a "wedge circle." The widest part of the wedge is closed off with a straight wall. The smallest part of the wedge is open to the circle. When the small solid collides with the wedged wall, randomly over and over again, the overall angle of reflection is counter clockwise. When the small solid collides with the straight wall, randomly over and over again, the overall angle of reflection is clockwise. top down view The small solid and wedged wall collisions are elastic. The small solid and straight wall collisions are inelastic. After colliding with the wedged wall the kinetic energy of the small solid is preserved in its overall counter clockwise reflection. While, after colliding with the straight wall the kinetic energy of the small solid is not preserved in an overall clockwise reflection. top down view So, over an extended period of time, the small solid will move in an overall counter clockwise circular path. When the small solid moves in an overall counter clockwise circular path, and does so over and over again, is "work" being done? --- 1. A Feynman Brownian Ratchet fails to produce rotation in one overall direction because larger and smaller fluctuations in Brownian Motion in the fluid and solid elements of the system push and retard the ratchet "forwards" and "backwards" equally. While in the question presented here, the Brownian Motion in the small floating solid and in the solid barrier walls will randomly make the reflections more or less clockwise and more or less counter clockwise. With these variations in the angles of reflection being random, however, the probability is that overall they will have no net effect. This question is not just another version of the Feynman Brownian Ratchet. Here, there is a small solid having elastic and inelastic collisions with angled solid barrier walls. 2. The collisions do not have to be perfectly elastic or inelastic. If the collisions with wedged wall are more elastic and if the collisions with straight wall are more inelastic, an overall counter clockwise circular path is still created, and the question remains. 3. If the space above the liquid is filled with air, then the Brownian Motion interaction between the gas and the barrier walls can complicate the analysis. This is eliminated if we assume a vacuum and not air in the space above the liquid. 4. When the small solid collides with the inner circular wall, randomly over and over again, the overall angle of reflection from this is neither more clockwise nor more counter clockwise. 5. It would be more accurate to say "When the small solid collides with the wedged wall, randomly over and over again, the probability is for the overall angle of reflection to be counter clockwise." And, it would be more accurate to say "When the small solid collides with the straight wall, randomly over and over again, the probability is for the overall angle of reflection to be clockwise." So, if the collisions with the wedged wall are elastic and the collisions with the straight wall are inelastic, the question should then be "When, as is probable, the small solid moves in an overall counter clockwise circular path, and does so over and over again, is "work" being done?" 6. If the collisions with the straight wall are perfectly inelastic, from time to time, the small solid will come to a stop and its kinetic energy will be returned to thermal energy. If periodically stopping seems problematic, then the straight wall can be removed and replaced by an outer circular barrier wall where the collisions will be elastic. Now, the small solid will move in an overall counter clockwise path while within the inner "wedge circle" and will move in an overall clockwise path while within the outer "wedge circle." 7. If "work" is being done, what are the second law implications?