From: tjroberts137@sbcglobal.net   
      
   On 8/8/19 1:39 AM, Nicolaas Vroom wrote:   
   > The two postulates of SR are:   
   > [... a PARAPHRASE]   
      
   > In the book 2 "Spacetime Physics" by Taylor and Wheeler we can read:   
   > [... a different PARAPHRASE]   
      
      
   > In the book 3 "The evolution of scientific thought from Newton to Einstein"   
   > by A.d'Abro at page 451 we can read:   
   > [... yet another different PARAPHRASE]   
      
   > [... discussion bemoaning the differences among these PARAPHRASES]   
      
   All is resolved when you use the ACTUAL postulates from Einstein's 1905   
   paper:   
      
   1. The laws by which the states of physical systems undergo change are   
       not affected, whether these changes of state be referred to the one   
       or the other of two systems of co-ordinates in uniform translatory   
       motion.   
      
   2. Any ray of light moves in the "stationary" system of co-ordinates   
       with the determined velocity c, whether the ray be emitted by a   
       stationary or by a moving body.   
      
        [Earlier in the paper he defined the "stationary" system   
         of coordinates to be an arbitrary inertial frame. So   
         "stationary" is a label without semantic content.]   
      
   Note in particular that Einstein's statements are more precise than any   
   of the paraphrases. As I keep saying: physics is subtle and to   
   understand it one must be precise in thought and word.   
      
   Tom Roberts   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)