Space-time exchange invariance: Special relativity as a symmetry principle

Special relativity is reformulated as a symmetry property of space-time: sp ace-time exchange invariance. The additional hypothesis of spatial homogene ity is then sufficient to derive the Lorentz transformation without referen ce to the traditional form of the Principle of Special Relativity. The kine matical version of the latter is shown to be a consequence of the Lorentz t ransformation. As a dynamical application, the laws of electrodynamics and magnetodynamics are derived from those of electrostatics and magnetostatics respectively. The four-vector nature of the electromagnetic potential play s a crucial role in the last two derivations. (C) 2001 American Association of Physics Teachers.