Special relativity to a first observer O, and frame S′ (pronounced "S prime") belongs to a second observer O′. Since there is no absolute reference frame in relativity theory, a concept of 'moving' doesn't strictly exist, as everything is always moving with respect to some other reference frame. Instead, any two frames that move at the same speed in the same direction are said to be "comoving". Therefore, "S" and "S"′ are not "comoving". The principle of relativity, which states that physical laws have the same form in each inertial reference frame, dates back to Galileo, and was incorporated into Newtonian physics.
Relativity priority dispute relativity and Lorentz's electron theory. This is incorrect." [p. 96] Instead, Miller claims that the theories are mathematically equivalent but not physically equivalent. [p. 91-92] In his Einstein biography "Subtle is the Lord" (1982), Abraham Pais argued that Poincaré "comes near" to discovering special relativity (in his St. Louis lecture of September 1904, and the June 1905 paper), but eventually he failed, because in 1904 and also later in 1909, Poincaré treated length contraction as a third independent hypothesis besides the relativity principle and the constancy of the speed of light. According to Pais, Poincaré thus never understood (or at