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Le dim. 9 févr. 2025, 01:24, Alan Grayson <[email protected]> a écrit : > It says "Everything". Am I misreading? I am not faulting you for endorsing > a nonsense interpretation of QM, the MWI, but you seem to have the > privilege to limit what's appropriate for me. That's all. I suggest you > check out my last post to Jesse. AG > On Saturday, February 8, 2025 at 3:48:23 PM UTC-7 Quentin Anciaux wrote: > >> Mr. AG, read the f.....g name of the list. >> >> Le sam. 8 févr. 2025, 22:50, Alan Grayson <[email protected]> a écrit : >> >>> >>> >>> On Saturday, February 8, 2025 at 2:08:05 AM UTC-7 Quentin Anciaux wrote: >>> >>> AG, what your thought experiment highlights is not a dichotomy in the >>> definition of the paradox, but rather a fundamental difference between >>> simultaneity-dependent contradictions and frame-dependent measurements in >>> relativity. >>> >>> 1. Why simultaneity matters in the original paradox >>> >>> The original paradox only appears when people assume there’s a universal >>> "at the same time" across both frames. >>> >>> Once we apply relativity of simultaneity, we see that each frame has its >>> own internally consistent timeline, resolving the contradiction. >>> >>> 2. Why spatial juxtaposition doesn’t create a paradox >>> >>> The observers at the midpoint are not measuring simultaneity-dependent >>> events, they are measuring spatial lengths, which are inherently >>> frame-dependent. >>> >>> There is no expectation in SR that two observers from different frames >>> must agree on length measurements—even if they occupy the same location in >>> space at a given moment. >>> >>> 3. Space and time are similar but not interchangeable >>> >>> Yes, spacetime diagrams treat space and time symmetrically in some >>> respects, but SR does not make space and time fully interchangeable. >>> >>> Time has an asymmetric role in causality (events in the past can >>> influence the future, but not vice versa), while space does not. >>> >>> This asymmetry means that disagreements in simultaneity lead to apparent >>> contradictions if misunderstood, while disagreements in spatial >>> measurements do not—because SR already accounts for them via length >>> contraction. >>> >>> 4. Your thought experiment is just a different way of looking at length >>> contraction >>> >>> The observer in the garage frame sees the car fitting, because in their >>> frame, the car is contracted. >>> >>> The observer in the car frame sees the car not fitting, because in their >>> frame, the garage is contracted. >>> >>> These are not "contradictory" observations, just different >>> frame-dependent measurements—exactly like time dilation or >>> velocity-dependent mass. >>> >>> The original paradox relied on a false assumption of absolute >>> simultaneity—hence why simultaneity "resolves" it. >>> Your thought experiment doesn’t introduce a new paradox—it just >>> reinforces how relativity treats space and time differently and why length >>> contraction, like time dilation, is not paradoxical, just unintuitive. >>> >>> Quentin >>> >>> Hope this discussion about well known facts for about 120 years will end >>> and we can return to everything-list purposes. >>> >>> >>> Yeah, it's done, provided philosophical issues are excluded from "list >>> purposes". If you recall, Brent was insistent that in the context of the >>> paradox, there is no objective reality. This means, if anything, that the >>> results of SR are appearances, or just appearances, or mere appearances. >>> Resutls depend upon the frame of reference of observers, so there's no >>> problem if they're contradictory. OTOH, since clocks in the GPS system >>> experience measurable delays due to SR effects, its results surely seem >>> objectively real. But we can just toss that issue under the rug, as >>> "philosophy".and go on to "legitimate" list purposes, which exclude obvious >>> foundational issues which were not completely resolved in 1905. Included in >>> subjects which pass your test include arguments against frequentist >>> probability in QM because some probabilities are so small, they can't be >>> realized in the lifetime of the universe. DId it ever occur to you that >>> these unrealized probabilities might be the result of wf solutions that >>> extend infinitely in space and time? Have you noticed that the tails of >>> these wf's extend infinitely in time and space? Ignoring that, what is your >>> alleged solution; the MWI. Did it ever occur to you that at every >>> T-intersection, there is a countable set of outcomes for every turn, in >>> fact for any turn anywhere, by anything, including the common ant, the >>> multitude of species of flying insects. and prairie dogs whenever they look >>> around for predators? This is the foolishness you apparently endorse as >>> "list-purposes". What you apparetly prefer are non-interacting worlds, the >>> probability of each is indeterminate. And even on that single turn at any >>> intersection, you can't even explain how the sum of probabilites of a >>> countable set of outcomes can equal unity. In summary, IMO, you have a >>> self-serving view of the legitimate content of list purposes. AG >>> >>> >>> Le sam. 8 févr. 2025, 08:55, Alan Grayson <[email protected]> a >>> écrit : >>> >>> >>> >>> On Thursday, February 6, 2025 at 2:23:45 PM UTC-7 Alan Grayson wrote: >>> >>> On Thursday, February 6, 2025 at 5:28:34 AM UTC-7 Quentin Anciaux wrote: >>> >>> AG, this is the closest you’ve come to an actual discussion, so I’ll >>> give you a straight answer. >>> >>> Your question boils down to whether simultaneity alone is enough to >>> resolve the paradox, or if there's still an issue when two observers, >>> co-located in space but in different frames, observe contradictory outcomes. >>> >>> Why Simultaneity Resolves the Paradox: >>> >>> 1. The "paradox" only exists if you expect a single, universal answer to >>> the question, "Does the car fit?"—which would require a preferred frame of >>> reference. But SR explicitly denies the existence of such a frame. >>> >>> >>> 2. Simultaneity isn’t just a technicality—it’s fundamental to how events >>> are ordered in each frame. In the garage frame, the car is fully inside at >>> one moment because simultaneity in that frame aligns the back entering and >>> the front still inside. In the car frame, simultaneity shifts, meaning by >>> the time the back enters, the front has already exited. The disagreement is >>> built into SR itself. >>> >>> Addressing Your "Co-Located Observers" Thought Experiment: >>> >>> You suggest that if two observers are spatially co-located but in >>> different frames, they would observe contradictory facts. But this is where >>> you’re making an error. >>> >>> 1. Frame membership matters: Each observer is still bound to their own >>> frame’s simultaneity rules. Just because they are momentarily at the same >>> point in space does not mean they share the same perception of simultaneity >>> or event ordering. >>> >>> >>> 2. Contradictory observations are expected, not paradoxical: In >>> relativity, observers in different frames frequently measure different >>> physical quantities for the same event (lengths, time intervals, etc.). >>> This is no different. The garage observer measures the car fitting because >>> their simultaneity rules allow it. The car observer measures it not fitting >>> because their simultaneity rules say otherwise. Each observer’s measurement >>> is internally consistent in their own frame—so there’s no contradiction >>> within SR. >>> >>> >>> 3. Would additional observers change anything? >>> No. Additional observers in each frame will confirm their own frame’s >>> version of events, reinforcing the idea that simultaneity dictates >>> different conclusions. There is no paradox because neither frame’s >>> measurement is "more real" than the other. >>> >>> The mistake is assuming that because two observers are momentarily >>> co-located, they must agree on event sequences. They do not. Their velocity >>> relative to each other still dictates their simultaneity slicing of >>> spacetime, and that’s what resolves the paradox. >>> >>> If you truly accept that simultaneity is relative and that SR allows for >>> frame-dependent measurements, then you should see why "fitting and not >>> fitting" is not a contradiction but a natural consequence of relativity. >>> >>> If you still think there’s a paradox, then ask yourself: what >>> fundamental assumption are you making that requires a single absolute >>> answer to "Does the car fit?" Because that’s where the actual mistake lies. >>> >>> Quentin >>> >>> >>> FWIW, I wasn't seeking to prove in this thought experiment that there's >>> an absolute answer to whether the car fits. In fact, I was alleging the >>> opposite, that with juxtaposed observers at the midpoint of the garage, the >>> car fits in one frame, and doesn't fit in the other. What I was alleging is >>> that this result seems curiously similar to the paradox when using "at the >>> same time" erroneously, whereas in this thought experiment only"same space" >>> is involved, not same time. AG >>> >>> >>> What this thought experiment shows is curious *dichotomy *concerning >>> the definition of the paradox. As long as it's assumed fitting and not >>> fittling occur at the same TIME, a "timely" form of juxtaposition, we have >>> a paradox (ostensibly resolved by the disagreement about simultaneity). But >>> when SPACE is juxtaposed, it's *not* considered a paradox. You'll note >>> that in the spacetime diagrams we have one dimension of time and one of >>> space, which have similar properties, albeit not identical. We also know >>> that given the initial condition, the car never fits from car's frame of >>> reference, and for a sufficient velocity, it will fit from the garage's >>> frame of reference. So the model of the spatial juxtapostion of the >>> observers at the halfway point in garage makes sense. AG >>> >>> >>> >>> Le jeu. 6 févr. 2025, 11:36, Alan Grayson <[email protected]> a >>> écrit : >>> >>> >>> >>> On Wednesday, February 5, 2025 at 4:23:46 PM UTC-7 Alan Grayson wrote: >>> >>> On Wednesday, February 5, 2025 at 3:37:31 PM UTC-7 Quentin Anciaux wrote: >>> >>> AG, the fact that your only response is to repeat "PRICK" like a broken >>> record says everything about your inability to engage in actual discussion. >>> >>> >>> FWIW, we can engage in a rational discussion if you would cease making >>> accusations about my motives and state of mind. I've reviiewed some of your >>> earlier explanations of the alleged paradox, and your more or less constant >>> complaint that I downplay the role of simultaneity in the resolution. While >>> I admit that my initial proposed solution was mistaken -- that length >>> contraction was alone sufficient to resolve the paradox -- I still fail to >>> see why simultaneity does the trick. I say this because all it does is show >>> that fitting and not fitting cannot occur "at the same time". But once it's >>> acknowleged that each frame in SR has its own set of clocks, not >>> synchronized with the clocks in some other frame, the concept "at the same >>> time" is meaningless. So, if you agree so far, the question becomes whether >>> fitting and not fitting "at different times" remains a paradox to resolve. >>> Although, "at the same time" is meaningless, it's possible to imagine the >>> car midway within the garage, and two juxtaposed observers, one in each >>> frame, which observe the car fitting and not fitting, now NOT simultaneous, >>> but spatially co-located. Can this mean another form of the paradox is >>> alive and well, since each observer has contradictory observations (where >>> additional observers are added where necessary to confirm the >>> observations)? Although SR allows measurement to be frame dependent, why >>> isn't this stuation* essentially identical *to the one which requires >>> simutaneity arguments to allegedly resolve? AG >>> >>> -- >>> >>> You received this message because you are subscribed to the Google >>> Groups "Everything List" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected]. >>> >>> To view this discussion visit >>> https://groups.google.com/d/msgid/everything-list/997c5736-cf45-482b-9511-2cccdc7a1b48n%40googlegroups.com >>> <https://groups.google.com/d/msgid/everything-list/997c5736-cf45-482b-9511-2cccdc7a1b48n%40googlegroups.com?utm_medium=email&utm_source=footer> >>> . >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "Everything List" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected]. >>> >> To view this discussion visit >>> https://groups.google.com/d/msgid/everything-list/986b5bd9-7547-417a-b396-7797414ee9aen%40googlegroups.com >>> <https://groups.google.com/d/msgid/everything-list/986b5bd9-7547-417a-b396-7797414ee9aen%40googlegroups.com?utm_medium=email&utm_source=footer> >>> . >>> >> -- > You received this message because you are subscribed to the Google Groups > "Everything List" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion visit > https://groups.google.com/d/msgid/everything-list/79bb53ed-57ff-4aa2-ac1b-a0f0917069e5n%40googlegroups.com > <https://groups.google.com/d/msgid/everything-list/79bb53ed-57ff-4aa2-ac1b-a0f0917069e5n%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "Everything List" group. 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