In this paper the speed of light postulate is closely examined from the perspective of two inertial reference frames―unprimed and primed―in relative motion, revealing that the resulting inverse space-time transformation is in disagreement with the corresponding Lorentz transformation following from the light speed postulate and the coordinate’s transformation assumed symmetry with respect to the reference frames. It is demonstrated that the speed of light postulate actually requires length and time contraction with respect to the unprimed reference frame, length and time dilation with respect to the primed frame, resulting in the frames being at rest with respect to each other! When the coordinate’s transformation symmetry assumption is applied on the direct transformation resulting from the light speed postulate―which is shown incompatible with this assumption―, the Lorentz transformation and its inverse are erroneously obtained; it is shown to be restricted to certain coordinate relations, resulted in mathematical contradictions, and thus demonstrated to be unviable.