From: edprochak@gmail.com   
      
   On Sunday, July 1, 2018 at 3:52:39 PM UTC-4, Ed Lake wrote:   
   > On Sunday, July 1, 2018 at 10:29:01 AM UTC-5, Tom Roberts wrote:   
      
   >   
   > Within two closed inertial frames of reference *experiments* work   
   > identically. HOWEVER, when one frame of reference is observed from   
   > another frame of reference, the experiments may not work identically.   
   > The same laws are valid in EVERY inertial frame, but they can produce   
   > different results if one frame is moving relative to the other. The laws   
   > involve variables, such as the length of a second.   
   >   
   > < snip > pointless argument   
   >   
   > > You MUST learn to avoid implicitly using "God's eye", as there is no   
   > > such thing in modern physics. < snip > more of the same.   
   >   
   > No one but you is saying anything about "God's eye."  Einstein's theory   
   > says that if B is moving faster than A, then time will move slower for   
   > B.  And if C is moving faster than B, then time will move slower for C   
   > than for B. And if D is moving faster than C, then D time will move   
   > slower for D than for A, B and C. Etc., etc., etc.   
   >   
   > There is no "God's eye" involved.  Einstein just said that a   
   > "luminiferous ether" is "superfluous" if the faster an object travels,   
   > the slower time passes for that object.  Time comparisons can be used to   
   > determine who is moving faster than whom.  That works until the speed of   
   > light is reached, at which point time stops for the object moving at   
   > that speed.   
   >   
   > Ed   
      
   For the Gedanken experiment, time comparisons cannot be used   
   to determine who is moving, period. You are almost there   
   with your descriptions that used letters instead of train and   
   embankment.   
      
   So, I like to pose the experiment as 2  trains with windows   
   only on the side facing the other train. Nothing else to   
   reference. Tracks and embankments are out of sight.   
   Of course also extremely smooth ride, not vibrations to   
   indicate movement.   
      
   We can even imagine both trains are infinitely long,   
   or at least long enough to conduct our thought experiments.   
      
   Each car of both trains contains an observer, watching   
   the other train and and an experimenter conducting an   
   experiment to watch.   
      
   The trains move at speed V relative to the other.   
      
   Experiment 1   
   In one of the cars of train A, the experimenter drops   
   a ball. The observer in train B also records the   
   experiment.   
      
   Experiment 2   
   In one of the cars of train A, the experimenter shoots   
   a ball at speed V in the same direction as train B.   
   The observer in train B also records the experiment.   
      
   Experiment 3   
   In one of the cars of train B, the experimenter drops   
   a ball. The observer in train A also records the   
   experiment.   
      
   Experiment 2   
   In one of the cars of train B, the experimenter shoots   
   a ball at speed V in the same direction as train A.   
   The observer in train A also records the experiment.   
      
      
   SO what do they conclude?   
   Both conclude that a ball falls at a given rate   
   (the acceleration of gravity).   
      
   Both agree that when they drop a ball in their   
   own train, it falls straight down. and the both   
   agree that combined motions work the same within   
   their own train.   
      
   The same goes for light and time.   
      
   Particular observations may be different,   
   but are symetrical.   
      
   IOW, they agree that the laws of physics are the same   
   in both trains. If they published ballistics tables,   
   both trains would come up with the same results.   
      
   They do disagree on who is moving, and   
   no experiment can tell them the "correct" answer.   
   There is no "illusion" to dispel.   
      
   Ed   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)