A Seductive Fallacy
Keywords: Lorentz Transformation, Einsteins Theory of Relativity, velocity of light, experiment
It has been claimed since at least 1910 that the Lorentz Transformation and Einstein\'s Theory of Relativity are derivable without using the constancy of the velocity of light as a postulate. The proof makes three (in some versions, more) very basic and natural assumptions, and derives the Lorentz transformation with a constant velocity of light as the only possible transformation between moving inertial frames that satisfies experimental observations. It is shown that the proof is flawed by illegitimately interpreting a constant that has the dimensions of a velocity as the velocity of light, and by claiming that this is the only choice confirmed by experiment.