Since the coupling charge and the response coefficient for gravity are identical, it follows that gravity can only operate in a single directional sense, because changing the sign of m for a particle would reverse the sense of both the coupling and the response, leaving the particle’s overall behavior unchanged. In other words, if we considered gravitation to apply a repulsive force to a certain particle by setting the particle’s coupling charge to -m, we would also set its inertial coefficient to -m, so the particle would still accelerate into the applied force.

— 2.2  Force Laws and Maxwell’s Equations

— Reflections on Relativity

— mathpages

2013.06.09 Sunday ACHK