Dear Eckard,

My sincere apologies. I see I've been missing out on a very interesting discussion. Before I read through it and try to join back in, I want to refer back to your post on Jul. 7, 2013 @ 06:43 GMT. Since I've fallen out of sequence there, I'm posting this in a new thread.

The only thing that bothers me in what you wrote is the statement that you "consider it fallacious to have different perspectives at a time".

I think you're thinking too much about these people making observations and not enough about what their natural definition of space and time should be. I think we can get to the former easily enough after we deal with the latter--so I just want to ask you: do you think it's unreasonable for Albert to string out a measuring tape along the track and plot a graph of what he perceives as occurring along that axis of "space" through the course of "time"? Or to add a vertical tape measure and make a two-dimensional graph of an object's path through the two spatial dimensions? Or make a full three-dimensional graph?

Do you think it's any less reasonable for Henri to string out measuring tape along the floor and the wall of the train car and do something similar?

The principle of relativity says that they should both be able to do this, and the laws of physics should apply just as well in both of their frames.

Now, the clocks that they have with them in the first phase of the experiment have the same vertical distance between the mirrors, and a single photon bounces up and down. When this happens, the clock displays the number of "ticks", sending photons in all directions (and in these guys' frames of reference they can correct for the amount of time it takes those photons to reach their eyes by travelling through "space", etc.), so the experiment can actually be carried out in theory. But that really doesn't need to happen if you already just accept that their two coordinate systems are reasonable to use, because then you already know what's going to happen, from either perspective.

From Albert's perspective, H's clock moves to the right. The path of the photon in the clock on the train is therefore not vertical, but moves at an angle to the right. By the Pythagorean theorem, it travels a longer distance than the photon in Albert's clock, which just went up or down. Assuming c is a universal constant, this means that the "tick" of Henri's clock, as described by Albert, takes longer (t=d/c) than the "tick" of Albert's clock, as described by Albert.

The paradox is that the whole experiment can be *described* from Henri's perspective, where he just sits at rest and Albert moves gradually along his ruler. From Henri's perspective, the photon in his own clock goes vertically up and down, and it's Albert's that travels to the right. For all the same reasons as before, we conclude that as described in Henri's frame of reference, Albert's clock ticks more slowly than Henri's.

You said before that you "question the necessity to ascribe a different proper time to the observer" (meaning Albert in this example). This is the reason why. Relativistic time dilation is a real effect in the real world, and it's not a trivial problem to reconcile the fact with the ticking of an absolute clock. You also said that to you, "only the motion of the observer re train, or vice versa, is relevant", and not whether the train is actually moving. This was Einstein's way of thinking, and it's why I said before that you were thinking as a pure relativist. And the issue--the reason you and I are not seeing eye to eye, as far as I can tell--is that without defining a true cosmic frame of reference, actual or absolute motion, etc., and considering only relative motion as what matters, it's logically inconsistent to say that there is one absolute time, three-dimensional space is all that exists, time passes and all of reality is the three-dimensional present that exists "now", etc.

Time-dilation has to be admitted from a relativistic perspective, and it has to be reconciled with a global reference frame in order for it all to work. The way of actually allowing that their proper times tick at different rates while admitting an absolute time and the *existence* of a three-dimensional universe, is to define simultaneity as absolute, and therefore as something different from synchronicity. You and Paul are right that Einstein got simultaneity wrong, by defining it from an operationalist point of view. This is the point I keep trying to make. And I keep trying to show exactly how relativity works--and it works beautifully!--when it's understood in this way.

Cheers,

Daryl

    Dear Eckard,

    I think I see a possible point of confusion that might lead to you objecting to my above post. In your post above on Jul. 10, 2013 @ 21:44 GMT which you addressed to Christian Corda and Paul, you wrote "My objection does merely refer to the interpretation that the laws of physics provide the same picture if applied to the different perspectives of two moving relatively to each other inertial observers A and B - AT A TIME".

    First of all, it's not "the same picture", but that they apply equally as well from either perspective, as the descriptions from either perspective, as related through continuous coordinate transformations, are consistent with one another.

    I think you may be thinking too literally about this "AT A TIME". The measure of time in two different frames of reference is not the same (e.g., as per the above), so there is no consistent way of saying "at the same time" when talking about the descriptions from two different perspectives. Because of this, I think you're arguing that it's only relevant to describe things from one frame of reference or the other.

    But the point I think you may be missing when someone says, e.g. "at the same time you can describe things from one perspective or the other", is that what is really meant by that, is it's not just that things can be described in either frame of reference, end point, but that there is a continuous transformation between the two descriptions which allows the same sequences of events to be described either way.

    I hope that helps, and if I'm just misunderstanding you, I do apologise.

    Daryl

    Paul,

    You said you find it stunning that anyone ever read past section 1 part 1. The reason is that everything was headed towards positivism. It was a load of positivists who got us to where we are today.

    Regarding your answers to Eckard's question, I don't disagree with them, except for the last one. I've now written two essays arguing for the same presentist position as you, and against Einstein's "simultaneity=synchronicity", and trying to explain in detail just how relativity should be more objectively interpreted, and you simply object to everything. I think the closest you've ever come to agreeing with me was above, where you said you thought I'd agree with something you had written, but then proceeded to state your belief that there has to be a difference in our views.

    Please let me state once more exactly where Einstein went wrong on the whole simultaneity/synchronicity issue:

    A and B stand a distance d apart and B signals A. It takes t=d/c from the time of emission to the time of observation.

    Now A is jogging towards B and B signals A when A is precisely d away. It takes t

    Dear Eckard and Paul,

    I have some comments. First of all, reading through this discussion has confirmed for me that I was right (see below) about the point of "at the same time" being a point of confusion in this discussion. Eckard, when one says that one reference frame or another can be used to describe events, the meaning is not that one person can be in two places at the same time. The meaning is that any frame of reference is suitable to describe the same sequences of events. And the theory *does* provide a consistent way to transform from the coordinates of one frame to another.

    A simple exercise will help you to see this graphically. Draw a vertical line and a horizontal line and call them t and x, respectively. Now draw the lines t=x and t=-x. Now draw another line passing through the origin, rotated 30 degrees to the right of the t-axis. Call that t'. If t=x and t=-x represent the paths of photons through x in t, which both recede from an observer who sits at x=0 with unit velocity, and if the line t' is the worldline of another observer who moves through x in t, then clearly the photon that moves along t=x isn't moving away from this observer as quickly as the one that moves along t=-x.

    But motion and speed are all relative anyway, and we want to be able to say that the photons both recede with unit velocity from the perspective of this other observer as well. Something tells me you think this can't be described consistently on this same graph--i.e., that a consistent description can't be given at the same time from either perspective. Am I right about this? Again, my sincere apologies if I'm mistaken about this point of confusion.

    Anyway, it can. Draw a line rotated 30 degrees above the x-axis and call it x'. Now draw a line parallel to x' that lies somewhere above it. You should now have seven lines on the page, so it's getting a bit messy, but we're done drawing lines. Now, on the last line you drew, I want you to draw a dot where it intersects the two photon world-lines as well as where it intersects t'. These three events are synchronous along this observer's proper axis of space at this particular value of t'. And the distance that the two photons travelled from t'=0 to this value of t' should be the same in either direction along x'. If you drew the graph with a ruler, you can measure it.

    Therefore, "at the same time" the same sequences of events can be described from both perspectives, and indeed, from either observer's perspective the speed of light is the same in both directions.

    The only extra bit, in bringing things up to speed with Minkowski's 1908 paper, is that in order for the speed to have the same magnitude in both coordinate systems, this has to be a hyperbolic transformation, which rescales the axes relative to one another. Graphically, that's all there is to the Lorentz transformations in SR.

    And indeed, you should plainly see that the synchronous events in one coordinate frame are not synchronous in the other. But both frames do provide accurate descriptions of the same sequence of events.

    Now, you've asked if there is a naturally "privileged" perspective. If there's to be absolute simultaneity--i.e. if Einstein got it wrong when he defined synchronous events as simultaneous, and there's only a 3D Universe Now--then there has to be an absolute reference frame, relative to which bodies are either actually in motion or not; and when they actually are in motion, the actually simultaneous events will not be described by them as synchronous.

    Daryl

    Sorry, I forgot that the less than symbol doesn't work here:

    Now A is jogging towards B and B signals A when A is precisely d away. It takes t less than d/c from the time of emission to the time of observation because light travels at a finite speed and A jogged a little further so the distance the light travelled was less than d when A eventually observed it.

    Now A and B lock themselves up in the cabin of a ship and close all the windows. They stand a distance d apart and B signals A. How long is it from the time of emission to the time of the observation?

    "Well, dumb-dumb," says Einstein to Newton, "it obviously has to be t=d/c because all that matters is how they describe things in their local frame of reference. I know it seems silly if you know that the ship's actually moving; but what's 'real' motion anyway? And I know the consequences are weird--there's no such thing as Now; time doesn't actually pass; there's no objective distinction between past, present, and future; etc.--but how could it be any different when you can't ever know whether the cabin is really moving or not. And you can't ever know whether the cabin is really moving or not."

    Except you *can* know whether the cabin is really moving or not.

    And while the theory *can* be used to describe everything that happens from any reference frame, because that's one of the basic principles that's in its design, you can't then turn around and use the fact as an argument that there's no such thing as "actual" motion, time doesn't actually pass, there's no "Now", and reality has to be described as a block universe. Logic doesn't work that way. It's like Ken Wharton wrote in his essay (he was referring to something else, but the argument still applies): it's like putting on rose-tinted glasses in order to justify claiming that the world is actually red.

    It's been a hundred years, and hardly anyone will listen to Newton's muffled reply, "But all you have to do is look at the world around you to tell if you're really moving or not. I agree that you can describe everything that happens in a coordinate system in which you're "at rest"; but come on, Albert, open your eyes: the Earth is moving through the Universe at 370 km/s. There *is* an objective definition of motion, and therefore an objective definition of Now.

    "Now, to get back to this business in which A and B are holed up in a cabin: if that cabin's actually moving--say along the line from A to B, in that direction--then after B signals A, A closes the distance a bit--i.e., the distance d between B and A at the time of emission, since A moves towards the point of emission and B moves away from it, so they maintain a constant relative distance from each other--so the actual time it takes the signal to get from B to A is t less than d/c. If you've got trouble with this, please refer to the above example where A is jogging towards B. It's the same thing."

    I agree with Newton and disagree with Einstein. For these same reasons, I think Einstein's definition of simultaneity is wrong.

    Daryl

    Daryl

    This is not what Einstein said. This is what people translate him as saying. What he meant to say was both correct and obvious (see below in respect of this paper that Eckard is referring to). The irony being that he had no observation, because there was nothing to observe with. So his c is not observational light, there are no frames of reference, etc, etc. His c is just a constant in order to calibrate distance and duration. This is why he then defines SR, in order to provide a circumstance within which the two 1905 postulates reconcile, before going on to GR.

    So, yes in practice, the distance AB is irrelevant, because the distance travelled is from source (ie the position B was in at that time) to when the light is received, and A is moving towards it. But, as I said, Einstein did not have any observational light. He was, in effect, just measuring AB as is, when it exists, ie at a point in time. And that can be done two ways. Either one can establish the spatial difference. Or one can express the distance in terms of duration for something to travel it, like light at a constant speed. It cannot actually do this, because AB can only exist at one point in time, it being the spatial difference between two physically existent states.

    Paul

    Eckard

    Re the essay you referred me to.

    There is no synchronisation problem, or at least only at a practical level, which is an entirely different matter and not what Einstein was concerned with. Neither do timing devices have to be synchronised by signal exchanges.

    His definition of Poincare/Einstein synchronization is wrong. Einstein did not say that clocks are synchronised by this method, in terms of telling the time, which is their function. He was saying that for them to indicate the time of occurrence of an event in any other spatial location, they would have to be synchronised this way. In other words, set out of synchronisation in order to compensate for the duration delay whilst light travels the distance between event and recipient of the light.

    Einstein 1905 part 1 section 1:

    "If at the point A of space there is a clock, an observer at A can determine the time values of events in the immediate proximity of A by finding the positions of the hands which are simultaneous with these events. If there is at the point B of space another clock in all respects resembling the one at A, it is possible for an observer at B to determine the time values of events in the immediate neighbourhood of B. But it is not possible without further assumption to compare, in respect of time, an event at A with an event at B. We have so far defined only an "A time" and a "B time." We have not defined a common "time" for A and B, for the latter cannot be defined at all unless we establish by definition that the "time" required by light to travel from A to B equals the "time" it requires to travel from B to A".

    His concept of "immediate proximity" is wrong, physically, as there is always a delay, but it is an understandable approximation. When not in whatever constitutes "immediate proximity", ie at B, the light from A will take some time to reach B (as opposed to at A where being in the "immediate proximity" is deemed to result in no time delay). In fact there is a time delay in all circumstances. So looking at the timing device at B will give a reading of time of theevent at A which is 'late', in terms of time of occurrence of that 'distant' event, as opposed to time of receipt of light repreentation thereof.

    What he is supposed to be writing about is the receipt of a light representation of reality. But, apart from the incorrect approximation with the 'immediate proximity', he gets this wrong because the last caveat is incorrect. All he needs is the time taken for light to travel AB, under 'perfect conditions'. The 'common time' is only required for B in respect of A, or vice-versa, and it is not a 'common time' but an adjusted time taking into account the duration delay whilst light travels. In other words, discounting the different spatial position so that the reference is the same. And although he writes about clocks synchronising, what he means is that for the timing devices to, in any position, tell the time of the occurrence of an event in another spatial position, then they have to be adjusted to eliminate the time delay whilst light travels. He writes before this paragraph: "substituting "the position of the small hand of my watch" for "time." ". The word stationary, which is used throughout the section is superfluous.

    The simple fact is that a reality occurs at a time. In doing so it generates physically existent light based representations of it, which in some cases are received, at a later time, depending on spatial position, and in real circumstances, physical conditions encountered. The timing system is about all devices showing the same time, ie being synchronised, in the proper sense of the word, within practical possibilities. That is the reference is one conceptual constant rate of change.

    Paul

    Eckard

    Re the first postulate. We may have been talking at cross purposes. I am referring to the statement in the introduction, second paragraph. What does he actually write. You are referring to his statement at the start of section 2, part 1 (On the relativity of lengths and times).

    Paul

    Daryl

    "this has to be a hyperbolic transformation"

    ? surely, it is just a matter(!) of relative spatial positions and timings of receipt of light. One could assume, to make it simpler, that all light travelled in the same physical circumstances.

    Paul

    Paul, that's not anything Newton said either. I said it.

    But about Einstein, you're confusing two things. It's not just the first postulate that leads "him" to say what he says there, but the definition of simultaneity, as he did state it, because saying the time it takes light to cross the distance from A to B is equal to that distance divided by c is equivalent to making that definition of simultaneity.

    Daryl

    Paul,

    It's not actually as complicated as it sounds. It's just another way of saying that the Lorentz transformation takes you from one frame to the other. The point I was really trying to get at was that by tilting the axes in that way, light is described as moving through space in time at the same rate in either direction, in both coordinate systems. But yes, in order to make that rate actually the same constant value in both coordinate systems, the axes do need to be rescaled in this way.

    Daryl

    Dear Eckard,

    As I promised in my Essay page, I have read your Essay. Here are some comments.

    You wrote: "Kramers-Kronig relations guarantee that the future does not influence the past. They allow calculating the imaginary part from the real part and vice versa of any complex function that is analytic in the upper half-plane. Analyticity implies the directional aspect of causality and vice versa. Time scale can be shifted without any restriction." This does not work in general relativity and in general in metric theories of gravity. He was Goedel who discovered a solution to the field equations of general relativity, in 1949, which permits the existence of closed timelike curves. You claims in my Essay page that "The current physics follows Einstein, Hilbert, and Wheeler in assuming a block universe without a now that separates the past from the future." Actually, Einstein, who disagreed with the existence of singularities, never avoided the possibility of the existence of such closed timelike curves. Instead, he claimed that "Goedel's solution gives me a shiver running down my spine". It was instead Hawking who labeled the chronology protection conjecture. I suspect this is due to the issue that the non-existence of closed timelike curves is a strong constrain for the singularity theorems.

    You wrote: "Wheeler's S-matrix is not just a tool but it already represents his inclination of attributing physical reality to any mathematical model." I disagree. Being unitary, S-matrix simply represents the respect of the rules of quantum mechanics and information preserving in physical evolutions.

    You wrote: "We may derive from Maxwell's equations (without convection terms) a speed of radar waves in vacuum that is consistent with just one time common to all locations, see the endnotes. It does not depend on the velocities of emitter and receiver in space. Only a reactive evanescent component near to each antenna moves with the antenna, but it does not propagate." I did not find this point in the endnotes, please, clarify. Also recall that Maxwell's equations are a consequence of Special Relativity.

    You wrote: "Any distance d of a location under consideration from a chosen one and also any time span t that has now elapsed since a chosen moment have naturally positive real values. This conflicts with the tenet that there is no common time but different local times." I do not see the conflict if one uses the Lorentz transformations. Please, clarify.

    You wrote: "Infinitely long rigid bodies (coordinate systems) [21] could transmit energy and information with any velocity, even with a velocity in excess of c." Actually, rigid bodies do not exist as they violate the Uncertainty Principle. Coordinate systems are merely abstractions that we use to describe phenomena.

    You wrote: "Einstein's constancy of c relative to any observer is not convincing as long as it implies different influences of differently moving observer on the same received light." This point does not convince you, I do not see problems and you must recall that it is valid ONLY for inertial observers.

    Cheers,

    Ch.

      Dear all

      (in alphabetic order: Christian Corda, Daryl Janzen, Edwin Klingman, Israel Perez, Paul Reed, Pentcho Valew, Sean Gryb),

      You uttered arguments concerning Einstein's special theory of relativity that are more or less at variance not just with my endnotes but also among each other. While I am pretty sure being correct in that the future is quite different from the past, I merely suspect that length contraction was fabricated in order to explain the null result of Michelson's 1881 and 1887 experiments.

      Israel, you wrote to me:

      "These words "fabricated" and "rescuing" suggest me that either you are not fully understanding the physics or you are not aware of it. Einstein also labelled Lorentz contraction as ad-hoc hypothesis. Fortunately, more recently, people are starting to understand the great insight of Lorentz and they are realizing that Einstein was fundamentally wrong."

      I just follow David Bohm who explained in his textbook on Special Relativity Lorentz's "attempt to rescue the ether".

      Then you asked me:

      "do you have any other plausible explanation to the outcome of the MMX that doesn't invoke time dilation and length contraction? Actually, there are not many explanations, another option that comes to my mind is the so-called emission theories. But I have already studied it in great detailed in the past and the solution is not consistent. Do you have any other option in mind?"

      For a while I favored Maxwell's light-carrying aether because I got aware of incorrectness in the calculated expectation by Michelson and Morley. However, this small incorrectness was already mentioned by these authors and cannot account for their null result. Norbert Feist did also correctly perform his experiment but he misinterpreted it as support for the ether hypothesis.

      Edwin Klingman, you offer rather in passing a new idea: Light is carried by the gravitation field which symmetrically surrounds the earth. This, you argue, could explain the null result, too. This alternative sounds exciting. I only didn't get aware of anybody who noticed it. I myself cannot judge it.

      Pentcho Valew, many but certainly not all of your arguments against Einstein's theory of relativity are obviously irrefutable. You are still interpreting Michelson's experiment as evidence in support of emission theory because Michelson disproved Maxwell's theory of ether. In contrast to you, I see the emission theory, which goes back to Newton and was again suggested by Ritz, not just at odds with many properties of electromagnetic waves in application to electrical engineering. I see it suffering from the same deficit as did Maxwell's ether theory: They continued to imagine electromagnetic waves somehow bound to something traditionally tangible: either quasi-material particles of light or a conveying material medium to propagate within. As did Einstein in 1905, I question the hypothesis of ether, and I trust in my own experience that confirms c as the limit to the speed of light, of signals, and of energy propagation.

      Daryl Janzen, you criticized in particular the block universe and the notion existence but you introduced Albert (A) and Henry (H) as to reiterate Einstein's these that the simultaneity of distant events is relative. You also try to lecture me that "relativistic time dilation is a real effect in the real world". You wrote:

      "The way of actually allowing that their proper times tick at different rates while admitting an absolute time and the *existence* of a three-dimensional universe, is to define simultaneity as absolute, and therefore as something different from synchronicity. You and Paul are right that Einstein got simultaneity wrong, by defining it from an operationalist point of view."

      Did someone follow your suggestion to distinguish between Einstein-synchronicity and simultaneity?

      Paul Reed, if I understood and recall your comments correctly, you agree in principle with Daryl, Israel, and most other physicist on that length contraction and time dilution are real effects. You merely substituted the word contracted by altered. Presumably, you do not trust in the counterintuitive quadratic dependency on v.

      Since I cannot yet see progress toward an agreement on correct solutions to a bundle of diverging opinions, I will try and explain my reasoning step by step in one more post. So far, I would like you to confirm that we may restrict our consideration on two points A and B located in vacuum and moving along a straight line with constant velocity v away from each other.

      Christian, after uncounted failed attempts I just got again access to the internet and found your comments on my essay. I highly appreciate your effort, and I found interesting details in it but not yet any serious argument against Shannon's view. You will hopefully not take it amiss if I postpone my detailed reply.

      Regards to all,

      Eckard

        Daryl

        Not so. Expressing a distance in terms of how long it would take light, at its perfect constant speed, to travel that distance is a valid alternative to expressing the distance in terms of difference in spatial locations. Establishing when an event occurred by comparing the timing of different receipts of light from that occurrence, is something else.

        His definition of simultaneity was meant to just be a compensation for observational light travelling. In other words, for two timing devices to be in the same observational frame, when they are at different spatial locations, then one has to move the time on one of the devices forward/backwards. Which is obvious. Another way of effecting that is just to look at the time, with all the devices synchronised to the same time, then on the basis of knowing the differential in spatial position, adding/subtracting the relevant duration.

        The issue is that Einstein, with the best of intentions, then had no observation. So in effect, this differential was attributed to being a characteristic of existence itself. What he stated is irrelevant, if he did not then do what he stated!

        Paul

        Daryl

        The Lorentz transformation does not take you anywhere, gamma is just the ratio of the transversal to the vertical. At the theoretical level, the way to convert one frame to another is to establish the spatial difference at the time of receipt of light, then deduct/add the duration incurred whilst light travelled that distance, ie one assumes a constancy of light speed. In practice, environmental conditions may affect the various lights.

        Paul

        Eckard

        As I have said before, it is first best if you understand what SR is, according to the man who wrote it. Then any comments you make about Einstein's concept of relativity can be properly focussed on what, in effect, it was.

        Why are you only "pretty sure" that the future is different from the past? Obviously it is, it is a different reality, the future not having occurred yet, and the past being a previous reality in the sequence that has ceased to exist. Reality being that physically existent state which exists at any given time (the present). Incidentally, something is either different or not different.

        I have seen no evidence that length contraction was fabricated. It was a genuine explanation by Lorentz and FitzGerald for what they thought was happening. And anyway, as I explained to you before, whilst that all needs understanding as such, it is irrelevant to the Einstein conundrum. Because he had no observation, there was nothing to observe with. He created the 'room' for variability by misunderstanding timing. So in effect, he attributed the relativity which occurs in the receipt of light, to the occurrence of existence itself, citing timing devices situated with the entities as the rationalisation. This is obvious when someone tries to explain Einstein. Cox and Forshaw is a very good example. They have light, a light beam clock, but if you are awake as you read it, then you ask, but where is the light that these observers receive? There isn't any. Somehow observers are observers without having anything to observe. Length alteration, as a result of a differential in force (later identified as gravity) incurred, may or may not happen. What this concept did was create a mind set that there was a relativity of some form or other. In 1905 it was irrelevant, explainable as a consequence. The same argument and numbers applied to the relativity of length as they did to duration.

        In respect of the part of this post specifically addressing me:

        -I do not know if length alteration, ie some physical alteration of matter in one dimension, as a result of a differential in force incurred, occurs. However, it is irrelevant for the rest of the argument. And the correct substitution of the word alteration for contraction is irrelevant. Remember, if it contracts, it must at some stage revert. Indeed, Lorentz, et al, wrote of 'returning to its rest state', but everybody just concentrates on the first part of the process. There was no concept that matter contracted, or indeed expanded, and then just stayed in that state.

        -time dilation does not occur, the existential rate of change does not alter. The only thing that does occur in this respect is an optical illusion. If there is relative motion, then the distance is altering between the recipient and the source of light, and hence the delay in each light which conveys the existential sequence will vary (either shorten or lengthen-a Doppler effect) for the recipient. That is, the perceived rate of change (time) will alter, but not the physically existent rate of change.

        -I do not understand your v comment.

        I await your next post to us. But remember this. A and B represent a discrete definitive physically existent state (ie a reality) at a given time. In terms of spatial position, these can only be compared at the same time. That is the distance AB is a differential in spatial position between two physically existent states at the same time. There can be no distance between something which exists and something else which does not. My underlying point being that they are not A and B, they are only A and B once. If they occur in a different physically existent state then they are different. And as I said above, different is different, not 'just a little bit' or whatever, ie it cannot be A and be different as well. This highlights the fundamentally incorrect way in which we are conceiving reality, by speaking of its (A's and B's) and changes thereto. A consequence of this is in respect of the equation x=vt. Distance can be expressed, conceptually, in terms of duration incurred. The concept being that instead of expressing distance as the fixed spatial quantity which it is, it can alternatively be quantified as the duration which would have been incurred had any given entity been able to travel along it, either way. But it must be understood that there is no duration as such, so this physically cannot happen, and it is just an alternative to, and the equivalent of, a spatial measure, ie a singular quantity.

        Paul

        Dear all,

        As a first step, I will try and explain my reasoning concerning synchronization. How to synchronize antenna A with antenna B when the distance between them steadily grows with velocity v?

        I assume:

        - Symmetry. The clock rate of A is assumed identical with the clock rate of B.

        - Antenna A emits at t=0 a signal to be transferred to B and corrected for the delay due to that transfer.

        - The distance d_0 at t=0 is known, and the distance d_1 at the moment of arrival t_1 can be calculated as d_0 + vT with T = t_1 - t_0.

        - The velocity c of light refers to the difference between the position of A at the moment of emission and the position of B at the moment of arrival, i.e. in the assumed case to d_1 divided by T.

        Obviously, the correction depends on the sign of v.

        There were perhaps three reasons for Einstein to apply Poincaré's synchronization.

        - He had realized that averaging the correction for positive and negative velocity yields a dependency of second order (a dependency on v squared) that corresponded to what Poincaré had dubbed Lorentz transformation, cf. his comment on "quantities of first order" in "On the Electrodyn."

        - He almost copied Poincaré and Lorentz although he didn't quote their papers.

        - He ignored to some extent logics and common sense.

        Eckard

        Dear Christian,

        In order to avoid that we merely agree to disagree on almost all you wrote, I would like you to first accept that Maxwell's equations were established long before 1905 when Einstein suggested his Special Relativity. You are not the first one who claims that Maxwell's equations can be derived from Special Relativity. I see such maneuvers as lacking obedience of causality among theoreticians. Nonetheless, I would appreciate you giving me a hint to such calculation on the web.

        I will reply to the many other questions as soon as possible to me.

        Cheers,

        Eckard

        Eckard

        I do not understand this post, or even if you have got the example correct. You say the "distance between them steadily grows with velocity v", which means there is relative motion, or they are travelling in different directions?

        Forget the clocks, these are irrelevant. And let us assume that the rate of change in reality is the same as that for light (this just makes the explanation simpler but does not interfere with the logic). [Note: you have presumed that physically A and B are identical over time, so the distance AB can always be measured using the same points on A & B, which will not be the case. Also, if there is relative motion, then there is the possibility that the differential in force incurred which is causing this could be causing dimension alteration].

        As each reality occurs, which in this example means a degree of change in spatial position, (it cannot be the same reality if something is in a different position), a light based representation of that physically existent state is created. The existential sequence progresses, and the resulting existent lights travel (we are assuming perfect conditions, ie all the lights travel at c). Now, if the distance between A and B remains the same, then the sequence of lights will be received, after the initial delay, at the same rate as they were generated, and as reality altered, ie the perceived (received) rate of change (timing) will be the same as that which is physically occurring. If the distance is ever changing, which could be a function of A and B travelling in different directions, ie their relative momentum is the same but the effect in terms of distance is the same as if they were travelling in the same direction but at different speeds, then the duration between the receipt of each light will change on each occasion as the distance alters, so the perceived rate of change will be different to that which is occurring.

        This might be what you are trying to explain, ie the caveat of 'uniform translatory motion' is wrong because it depends on direction of travel. But I am not sure, as the real point of his first postulate is that reality is unaffected by the reference used to calibrate it (albeit he invoked an unnecessary condition). [Incidentally, I have asked you for a translation of the sentence defining the first postulate in the Introduction, having realised that you are quoting the definition as in section 1 part 2 (On the relativity of lengths and times)].

        Poincaré starts with an incorrect view as to how timing works, ie not that the real reference is a conceptual constant rate of change, and the ability to synchronise timing devices to this is a practical matter, and not an issue about time. He then goes on to develop his A B example, with light transmissions to enable syncronisation. Einstein realises this is the equivalent of observation, so his A B example was supposed to be about synchronisation of light received. But as he developed his theory he had no observational light, just an example of light which was used as a reference, nobody saw with it, so the relativity in effect was attributed to existence.

        Poincaré, 1898, para 4:

        "All this is unimportant, one will say; doubtless our instruments of measurement are imperfect, but it suffices that we can conceive a perfect instrument. This ideal can not be reached, but it is enough to have conceived it and so to have put rigor into the definition of the unit of time. The trouble is that there is no rigor in the definition. When we use the pendulum to measure time, what postulate do we implicitly admit? It is that the duration of two identical phenomena is the same; or, if you prefer, that the same causes take the same time to produce the same effects."

        Poincaré, 1898, para 13:

        "To conclude: We have not a direct intuition of simultaneity, nor of the equality of two durations. If we think we have this intuition, this is an illusion. We replace it by the aid of certain rules which we apply almost always without taking count of them.

        But what is the nature of these rules? No general rule, no rigorous rule; a multitude of little rules applicable to each particular case. These rules are not imposed upon us and we might amuse ourselves in inventing others; but they could not be cast aside without greatly complicating the enunciation of the laws of physics, mechanics and astronomy. We therefore choose these rules, not because they are true, but because they are the most convenient, and we may recapitulate them as follows: "The simultaneity of two events, or the order of their succession, the equality of two durations, are to be so defined that the enunciation of the natural laws may be as simple as possible. In other words, all these rules, all these definitions are only the fruit of an unconscious opportunism."

        Poincaré, 1900, page 20:

        "It is the case that, in reality, that which we call the principle of relativity of motion has been verified only imperfectly, as shown by the theory of Lorentz. This is due to the compensation of multiple effects, but:...2. For the compensation to work, we must relate the phenomena not to the true time t, but to a certain local time t' defined in the following fashion.

        Let us suppose that there are some observers placed at various points, and they

        synchronize their clocks using light signals. They attempt to adjust the measured

        transmission time of the signals, but they are not aware of their common motion, and

        consequently believe that the signals travel equally fast in both directions. They perform observations of crossing signals, one travelling from A to B, followed by another travelling from B to A. The local time t' is the time indicated by the clocks which are so adjusted. If V = 1/√Ko is the speed of light, and v is the speed of the Earth which we suppose is parallel to the x axis, and in the positive direction, then we have: t' = t − v x/V2."

        Poincaré, 1900, page 22:

        "Suppose T is the duration of the emission: what will the real length be in space of the perturbation?...The real length of the perturbation is L = (V - v')T. Now, what is the apparent length?...the local time corresponding to that is T(1-vv'/V2). At local time t', it is at point x, where x is given by the equations: t ' = t − vx/V2,

        x = v'T + V(t - T), from which, neglecting V2: x = [v'T + V(t - T)](1 + v/V)...The apparent length of the perturbation will be, therefore,

        L' = Vt' - (x - vt') = (V - v')T(1 +v/V) = L(1 + v/V)."

        Poincaré, 1902, para 90:

        "1. There is no absolute space, and we only conceive of relative motion; and yet in most cases mechanical facts are enunciated as if there is an absolute space to which they can be referred.

        2. There is no absolute time. When we say that two periods are equal, the statement has no meaning, and can only acquire a meaning by a convention.

        3. Not only have we no direct intuition of the equality of two periods, but we have not even direct intuition of the simultaneity of two events occurring in two different places."

        Poincaré, 1904, page 6:

        "The most ingenious idea is that of local time. Let us imagine two observers, who

        wish to regulate their watches by means of optical signals; they exchange signals,

        but as they know that the transmission of light is not instantaneous, they are careful

        to cross them. When station B sees the signal from station A, its timepiece should

        not mark the same hour as that of station A at the moment the signal was sent,

        but this hour increased by a constant representing the time of transmission. Let

        us suppose, for example, that station A sends it signal at the moment when its

        time-piece marks the hour zero, and that station B receives it when its time-piece

        marks the hour t. The watches will be set, if the time t is the time of transmission,

        and in order to verify it, station B in turn sends a signal at the instant when its

        time-piece is at zero; station A must then see it when its time-piece is at t. Then

        the watches are regulated."

        "And, indeed, they mark the same hour at the same physical instant, but under

        one condition, namely, that the two stations are stationary. Otherwise, the time

        of transmission will not be the same in the two directions, since the station A, for

        example, goes to meet the disturbance emanating from B, whereas station B sees

        before the disturbance emanating from A. Watches regulated in this way, therefore,

        will not mark the true time; they will mark what might be called the local time,

        so that one will gain on the other. It matters little, since we have no means of

        perceiving it. All the phenomena which take place at A, for example, will be

        behind time, but all just the same amount, and the observer will not notice it since

        his watch is also behind time; thus, in accordance with the principle of relativity

        he will have no means of ascertaining whether he is at rest or in absolute motion."

        Yes Paul,

        A and B are merely assumed to increase their distance. It did not matter if they possibly traveled in the same direction. Only their relative motion matters.

        Thank you for quoting Poincaré:

        "they mark the same hour at the same physical instant, but under one condition, namely, that the two stations are stationary. Otherwise, the time of transmission will not be the same in the two directions".

        This fact was either overlooked or ignored by Einstein, and Einstein built on his wrong assumption of nonetheless equal times his theory of relativity including Minkowski's ict.

        Einstein wrote in 1905: [my translation]

        "the time the light requires in order to get from A to B equals to the time it requires to get from B to A".

        No, the relative velocity between A and B does not require acceleration and also not imply any force that could be suspected to cause length alteration.

        Eckard