Tim88

Bold face mine: Apparently Celeritas finally understood my criticism on his phrasing, and we agreed to disagree. The three of us teach here relativity of simultaneity. As I pointed out earlier, clocks in physical reference systems (by means of which simultaneity is indicated) do not automatically adjust to the velocity change as sketched. Therefore your statement that acceleration makes the traveler's reference frame rotate in spacetime -illustrated by your non-Minkowski spacetime diagram- suggests to me a misunderstanding of relativity of simultaneity (despite your great ability of drawing all kinds of instructive diagrams). In any case, I find it unhelpful for showing robinpike that the Lorentz transformations are self consistent.

I would say so. Time is a measure of the progress of physical processes, and that implies motion. Concerning stationary waves, they are fundamentally built up from traveling waves - at least that is what I learned in physics classes a long time ago. Assuming that the theory is correct, without time traveling waves cannot be created - even if one neglects that physical fact in the mathematical equation.

At big scale it's clear that things are deterministic. But I haven't made up my mind if at microscopic level ("quantum") level things are deterministic chaotic or indeterministic chaotic. Based on rational reasoning, all things are likely deterministic chaotic. But intuitively we appear to have free will; is that just due to lack of human predictability or due to inherent randomness? So, I'm on a logical level more a determinist, but on an intuitive level more an indeterminist!

Because of the wrong statement on which you based your self contradiction, I have an issue with the part that I put in bold. Expanding on my illustration, would you agree with the following: "A further conclusion, is that it is not necessary to include an apparent trajectory in order to deduce the real trajectory - they are separate things. When a real trajectory is followed to the point of the ball hitting the net, the presence of the real trajectory cannot be 'denied' by any particular observer's point of view. Whereas for an apparent trajectory, this can be dependent on a particular observer's point of view." It sounds as if you tend to confound "apparent trajectory" (or "apparent clock retardation") with the statement "it may be denied that the ball moved at all" (or "it may be denied that something happened to the clock"). I say this because your earlier conclusion would be, restated in the words of my example: "If these two trajectories were apparent effects – such a scenario would be possible. But the the effect of the trajectory - the ball hitting the net - is real and so these two conditions cannot occur together – hence a logical contradiction has occurred". But there only would be a logical contradiction if one would conclude that no trajectories occurred, based on the deduction that it is not necessary to include an apparent trajectory in order to deduce the real trajectory. By the way, the old literature is full of this kind of discussions, because SR removed the physical model that originally was at the basis of the Lorentz transformation, as "unnecessary". To fill up the conceptual black hole, people next made up their own interpretations to make sense of it; but not all of those interpretations and formulations really match SR, leading to much unnecessary confusion.

About your deductions: 2. according to SR it is not possible. However if you do not require that, then it's no issue. 3. according to SR all inertial frames agree with that; it's thus maybe not required. 4. on face value that may be correct, but it leads to the erroneous deduction in your foregoing post - the same error as explained earlier: The error was, and still is, that "apparent" does not mean "merely apparent". And I gave the illustration with the apparent trajectories: Remove the apparent trajectories and the ball cannot really hit the target. Voila, self contradiction! In my analysis - in agreement with Swansont's last analysis - your issue is probably more basic than the twin paradox; [edit: however you do use the twin paradox to infer that time dilation cannot be merely apparent.] After establishing that time dilation is a physical effect, your issue is with the much simpler mutual time dilation paradox. And that can be understood after understanding measurements of objects in motion, such as started in the spin-off thread on mutual length contraction in http://www.scienceforums.net/topic/98501-lost-in-langevins-language/

Hi Celeritas, As I have pointed out many times in this thread, time dilation and length contraction of SR are not optical effects. As I stated, my illustration was not about optical effects but about physically correct phrasing when using maps. I'll try one last time to clarify the illustration, by putting your words in it. The self made Dynamic Mercator method, which is just one method, constructs a map of how things "exist on Earth". The copilot cannot keep the shape of the coastline on his creatively constructed dynamic map constant, because the Earth's projection is not invariant across the sequential reference maps from which he assembles his dynamic map. But that doesn't matter and it's perfectly correct to say that the coastlines change shape when they are flying over; for that's what his dynamic map shows him; it's simply what his method does. What alternative does he have? I think that here you did understand what I meant: that kind of kinematics language is improper when giving a physical explanation in the context of explaining what "really" happens as a result of you suddenly turning around. However, it appears that you nevertheless deem that it's "no harm"... In view of that, I suppose that we will have to agree to disagree! PS. I insist: especially in this thread the topic is about consistency of physical description. In such discussions it's essential to use a single reference standard per physical description of events, and to correctly describe changes of reference standards as such - not as physical changes to objects that, according to the theory, are unaffected.

Bold face emphasis mine: OK, so you also concluded that the Eucharist of the Gospels is a later invention, and that Jesus did not really found Christianity. That does not leave much for a historical Jesus. Perhaps the main difference between your mainstream opinion and that of Mysticists, is that the Essene preacher whose preaching apparently has been included in the Gospels was the start of Christianity, that without his preaching Christianity would not have taken off. In other words, much of the polarization in the discussion appears a bit artificial. Let's see if the following coarse summary makes sense: 1. "Historical Jesus" (or, what is left of him by "mainstream"): - an Essene preacher named Jesus had followers - this Jesus was killed, his followers claimed to see him in visions and started a new religion - some Hellenistic teachings were added by Paul as well as later by others, leading to contentions - then the Gospel accounts were written and/or finalized, uniting the Christian communities. 2. "No historical Jesus" (generic): - Jews who had been waiting for Christ claimed to have seen him in visions, and so a new religion started - some Hellenistic teachings were added by Paul as well as later by others, leading to contentions - also the sayings of an Essene preacher, possibly named Jesus, circulated in the Christian community - the Gospel narratives put Christ on Earth and put the sayings in his mouth. Is that about right? PS and I see that, of course, Wikipedia now also has entries on this topic: https://en.wikipedia.org/wiki/Christ_myth_theory https://en.wikipedia.org/wiki/Historical_Jesus [edit:slight refinement]

You did not reply directly to my answer, which does not correspond to your summary. Instead, I pointed out the logical error in your argument. And in what follows after the cited section, you repeat that same logical error.

Celeritas, I wrote a few days ago: As they were short, I'll now paste them back in here: and then (red bold face emphasis new) And you replied: As you see, that was not exactly my point, which was much more general. But I'm glad to see that we are getting nearer as you realize that there can be issues concerning physical description when you do geometrical fitting; only there are more than you here seem to realize. And I suspect that maps of the rest systems of some inertial observers cannot be continuously mapped to your map at all; but that's a side issue. If I do measurements in the lab, I'm required to use consistent measurement tools, calibrated to the same measurement standard. Now, since you talk just like the copilot in my map example, it appears that you disagree with the standard requirements to measurements; and that you agree with the copilot that it's physically correct to state that in the airplane's frame the coastlines are changing shape while you fly over them.

I didn't express my opinion about the debate opposing physical space to physical space-time; but in my opinion the conclusion that there's more than just mathematical space-time is about as provable as the physical existence of for example magnetic fields. I guess that such fields are considered part of modern physics because they play a clearly identified, active role in equations. I'm curious to hear what counterarguments exist against the presented arguments. Although I don't follow all of Einstein's reasoning, and he mixes up his own reasoning with that of others, I think that he gives a good overview. If we go through the list that Einstein presented, https://en.wikisource.org/wiki/Ether_and_the_Theory_of_Relativity 1. He starts with gravity's action at a distance, which we know to be not immediate. This implies that far away from the original cause, locally an influence acts on objects. For such a local action to occur, something physical must be "there". However I would counter that one usually describes that as a gravitational field which can be imagined as something physical in itself, and not, as "field" originally meant, a property of space. 2. Next he gets to the topic of light propagation. In a nutshell, the second postulate is based on ether theory: the speed of light in vacuum is a constant, independent of the motion of the source (and also independent of the motion of the detector). And it seems to me that my counter argument about self existing fields does not apply for this case: far away from heavy masses the speed of light is effectively the same as very far from heavy masses. If I'm not mistaken, the argument that maybe the gravitational fields of far away stars impose the speed of light in interstellar space is not compatible with GR, and probably also not with observation. Thus I consider light propagation the first strong argument in the list for the conclusion that physical space itself has properties. Is there any other plausible explanation?

The reviews of Ehrman's pro-historicity book on Amazon are interesting and useful, for there we can find the opinions of people who have read the latest books on this topic: https://www.amazon.com/Did-Jesus-Exist-Historical-Argument/dp/0062204602/ref=cm_cr_arp_d_product_top?ie=UTF8#customerReviews [edit:] and this detailed review: https://www.amazon.de/review/RV49AMJHEFGO4/ref=cm_cr_dp_title?ie=UTF8&ASIN=B0053K28TS&channel=detail-glance&nodeID=530484031&store=digital-text Not sure if I'll buy that book....

Hi Memammal I now read the link you gave, http://infidels.org/library/modern/james_still/gospel_john.html and it's interesting indeed! The author James Still presents John's difference with the other Gospels as a Hellinization of a historical Jesus based on, among others, Philo. There is an obvious issue in view of Carrier's presentation of some of the same features of Philo's Jesus in Paul's writings as well as in Hebrews: Paul's writings are dated shortly after Philo, but John is dated much later. James Still seems to ignore Paul's portrayal of Jesus. However, perhaps you can fit that in with a historical Jesus, for concerning the Didache you remark: Are you suggesting that perhaps Paul created a faith to compete with the followers of Earthly Jesus, and that much later the communities merged so that in the end "John" was influenced by Paul's letters? Probably most scholars assume that there was Essene-based input to Christianity (perhaps related to the missing "Q" document) and that there were different competing Christian sects. It then all comes down to fitting them together on a plausible time and place map, with a plausible cause and effect logic. [edit]: it's unclear to me how you would explain the disagreement between that "Christian" Eucharist celebration and the one of the Gospels - except of course, if you take that away from the "historical Jesus". Very good, thanks! I quickly looked for a rebuttal by Carrier, but did not find one. I did find, BTW, his slide presentation: http://www.richardcarrier.info/Historicity_of_Jesus.pdf I guess that he'd better just remove the phrase (in bold face!) 'actually named “Jesus”' from his presentation; although it's striking there is no need for it and it's probably wrong. Such blunders do more harm than good (it can lead to what he calls the "fallacy fallacy").

Is there anyone here who wants to argue that there is only mathematical space-time, and thus argue against the presented arguments that space or space-time should be "substantial", or at least, contain something physical?

Haha it seems that we both got stuck in this discussion a little longer than intended. About Philo of Alexandria, it's 23 minutes into the video. Carrier says that according to Philo there was a Jewish belief about a celestial being called Jesus, who was the first born of God, the celestial image of God, God's agent of creation, and his high priest. I will have a look at the link you provided. And I don't know what you mean with "settle down", but concerning Paul and the Didache, indeed https://en.wikipedia.org/wiki/Didache#Eucharist adds nicely to my remarks. If there was a historical Jesus, there should be a "jump" from Jewish to Christian teachings on key Christian topics. About the denial section on https://web.archive.org/web/20070704232342/http://pages.ca.inter.net/~oblio/CritiquesGDon-2.htm , I found it too long to just refer like that so I indicated the location with 'from the phrase "central case of the crucified man and his cross"', which also tells you the topic of the denial by Minucius Felix. If you have Firefox (or similar), click on the Menu button, "Find", then paste and click on the arrow button to get to that section. Concerning the explanations that you offered: yes, sure, those were the historical reconstructions that I grew up with; they are based on the logical assumption that Christianity originated from a single location at a single time, as one should expect as result of a historical Jesus. Such reconstructions are one way of putting the pieces together, but some pieces don't seem to fit well and it's each one's opinion if the emerging picture looks plausible. And then to compare that with alternative reconstructions, how good or bad the pieces fit and how plausible that resulting picture looks, in comparison with the one tat we were all familiar with. And now I have found what may be a fair representation of the status quo of scholarly debate on this topic -as a good follow-up of the first post- and that is Ehrman vs. Carrier: http://astore.amazon.com/richardcarrier-20/detail/0062204602 http://www.richardcarrier.info/archives/1794 ?? Then you could also add for example the historicity of Herod and Pontius Pilate as evidence. It would indeed be too simple to ask if by chance there once was a guy with the name Jesus - the answer is surely Yes, no doubt about it. At a minimum, I think, "historical Jesus" implies a first century man on earth called Jesus who founded the Christian religion. As I understand it, a "historical Jesus" implies a single person who said and did at least some of the things ascribed to him, at those times and places, and without whom there would not have been Christianity. In short, a Jesus who mattered for history.

PS concerning the video of Carrier's presentation in the OP, I still read a little more, and I came, by chance again (it's indeed a very small world!) on the following phrase (emphasis mine): "the only way to kill mythicism is to prove that Paul knew of a historical Jesus. Given almost all scholars (all until Carrier's so far unexplained conversion) already think this is proven, the argument is unlikely to develop." - https://web.archive.org/web/20070704231459/http://pages.ca.inter.net/~oblio/CritiquesGDon.htm "unexplained"?

OK finally here's my take on the self contradiction in SR according to you (and as before, bold face mine, with a partial retake): What you describe here is very similar to what I described to you in my earlier post, and there is no contradiction: "From that perspective [of the system S2] the clock rate first is increased to its proper rate, and then on the way back home it is strongly decreased as the traveler tries to catch up with the Earth." The starting assumption of SR is the same as that of Newton's mechanics: any inertial reference system can be chosen for the description of physical phenomena. It's a feature of the Galilean transformations that this works in Newton's mechanics. And it's a feature of the Lorentz transformations that this works in special relativity: if we choose the inertial system S2 for the description of physics, we describe the phenomena somewhat differently (figuratively speaking, "from a different perspective") but we make the same prediction about the clock retardation of C1 on C0 when they are back side by side. I have the impression that we are back to the logically fallacy that I pointed out earlier: the mistake to think that everything must be either "only apparent" or "fully real". In fact, your own type of illustration serves well here. If we have disagreeing measurement tools, or if you see the trajectory of a volleyball from one angle and I see the same from another angle, then we could disagree about the trajectory. But we will still agree if the ball falls through the net or not. Where is the self contradiction? Or maybe you think that the time dilation effect cannot be mutual, so that the clock on Earth cannot be running slow according to the inertial system in which C2 is temporarily in rest? Hi Celeritas, I'm still waiting for your comments on my examples in which I illustrated that your presumed "B spacetime system" may be suited for geometrical descriptions, but it's not generally valid for the laws of physics - as you apparently know.

I see that the fonts are different, so that in your post on my screen the length contraction factor in the sketch is slightly different. Anyway, the car's frame measurement is as follows: The car's observers measure distances on the ground. The "car's" measurement is that the distance between the two balls on the ground is 1m. Celeritas elaborated on the Lorentz transformations in post #14 and I think that he explained it nicely. Be aware that Lp there corresponds to the proper length of the "rest system" S - which is this moving length measurement the car. But after loosing time on this, I'm afraid that something went wrong and he messed up the equations, as x’sep = γ(Lp-v(t'2-t'1)) is, I suppose, short for: x’2 - x’1 = γ ((x2 - x1) - v (t'2 - t'1)) which corresponds to the subtraction of two transformations of the type: x’ = γ (x - vt') But the Lorentz transformation in the direction of motion is: x’ = γ (x - vt) Thus, concretely: x2 - x1 = 1 m x’2 - x’1 = 1.5 m γ = 1.5 1.5 = 1.5*1 - v*<time difference between the events according to clocks in the car>

I disagree with the first, and totally agree with the second statement above. It's an interesting topic. it will be fun to discuss such things as how our "conscious now" functions according to our interpretations of SR in the philosophy forum.

Borrowing from bvr, I sketched for Michel that "particular case" of Langevin's general statement. PS I had already done so in post #7, but apparently an illustration with a car and dropping balls on the ground is more appealing than two rulers with lasers. And balls are easier than lasers for illustrating the reciprocity thanks to relativity of simultaneity. For Michel I'll refine the explanation by including the detailed view that I presented in post #7 to the last picture in the overview of post #24, and by adding the elements of the car and ground illustration in all applicable sentences by Langevin: __________________________ | | | | | c1 c2 | / \--- ----1m---- ---/ \ ___________\__/___o__"1.5m"__o___\__/___________________ <-- v (from the view that the car is in rest, the ground is moving to the left) Here's a "zoom in" on those rulers, according to the car's inertial rest frame: car [cm] 00 10 20 30 40 50 60 70 80 90 100 I I simultaneous positions "in" the car ground ["cm"] 00 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 According to the determination with the "car frame", the ruler on the "moving" ground is length contracted by a factor 1.5. A 150 cm long ruler on the ground is contracted to 100 cm, according to observers who take the view that the car is in rest. The spatial distance of two events that are simultaneous for the car observers, is shorter for them than for ground observers in motion relative to them: ds2 = invariant = (dx2 + dy2 + dz2) - c2dt2 Simultaneous means that the time between the events dt=0 => dx2 + dy2 + dz2 is maximal for the car observers in this example. This statement contains, as a particular case, what is called the Lorentz contraction, that is to say, the fact that the ground ruler considered by different groups of observers, some resting on the ground, others in motion relative to it, is shorter for those who see the ground ruler passing by as for those who are attached to the ground ruler. We have already seen that the length of the ground ruler for observers who see it passing by, is defined by the distance in space of two simultaneous positions (for those car observers) on both ends of the ground ruler. According to the preceding this distance will be shorter for those car observers than for all others, especially those attached to the ground ruler. We also easily understand (from the illustrative pictures in post #24) how the Lorentz contraction can be reciprocal, that is to say how two rulers that are equal when at rest, appear mutually shortened when they slide against one another, and observers attached to one of the rulers will see the other one shorter than its own. This reciprocity holds, because observers associated with the two rulers in motion relative to each other don't define simultaneity the same way. [edit: added the space-time equation]

In that post I refer to an inertial reference system, in which from two fast moving clocks, one clock (the "traveler") slows down to zero speed when leaving the Earth. All such determinations are non-absolute in the way as you illustrated.

One last time, hopefully it will be clear to you one day: __________________________ | | | | | c1 c2 | / \--- ----1m---- ---/ \ ____________\__/___o__"1.5m"__o___\__/___________________ The spatial distance of two events that are simultaneous for the car observers, is shorter for them than for ground observers in motion relative to them. This statement contains, as a particular case, what is called the Lorentz contraction

Indeed, as I emphasized, it's the other way round: the events are simultaneous for the car's rest frame. However, there is no "crossing of frames"; such a concept is not SR. 1.5 m is the ruler reading of the moving ground frame according to the car frame. That is a measure of the length contraction of that moving ruler according to the car; there is nothing to worry about! [edit:] Maybe you forgot to read to the end? Here it is again: Full situation from the car's perspective: __________________________ | | | | | c1 c2 | / \--- ----1m---- ---/ \ ____________\__/___o__"1.5m"__o___\__/___________________ That is philosophical interpretation by Einstein in the 1950's (your 1916 one did not fit in there), in complete disagreement with his own interpretation around 1920 and that of Langevin in 1911 (whose paper is discussed here) as well of that of Lorentz. Einstein did not possess SR, and he did not claim that either; and it was on purpose an operational theory, free of such ideas as ether or block universe. Once more, please discuss that in the appropriate thread; block universe philosophy is not the topic here. [edit: little addition]

In my adaptation of bvr's example, yes, that is the measurement as taken from the Earth. But I see no need for a mathematical operation. The physical operation that the earthling does to determine proper length, is to simply put a ruler between the balls. As the balls are not moving relative to the ruler, no timing is needed. This proper length is the measured distance between the balls on the ground.

There is no need for assuming different 3D realities, as most of us are trying to explain in the thread on clocks and rulers. In the paper that is discussed here, where do you see a suggestion of multiple 3D realities? Further, you are advocating the block universe philosophy while you could equally well argue for the 3D ether. Which reminds me of the Rules (by chance I just had a look at them, see "Converting the Heathens"): http://www.scienceforums.net/topic/7813-science-forums-etiquette/ Such discussions probably belong in the philosophy forum - and a related topic is actually being discussed there: http://www.scienceforums.net/topic/97105-is-space-time-a-physical-entity-or-a-mathematical-model/

I don't think so, a deterministic universe is in my opinion a totally different topic, as a 3D universe can be deterministic. PS. It may be useful to spin the discussion about the space vs spacetime debate off to a dedicated thread though.