infinite              spacetime          equals infinite                             motion;
             finite                            spacetime equals                               finite motion.                                   there
     can only be one;                                      no thing is infinite              
                                          ­                                                               except
infinity itself which                 if a thing is                                        
                                spacetime
if                    ­   spacetime is a thing;       if time is                                   a thing  it
is infinite;                    space is not infinite by               definition