From: "Justin Schwartz" <jkschw at hotmail.com>
I guess I would put my explanation of this point in realist terms: there is one world, and it is the way it is; we find out about it through scientific inquiry. If our theories are approximately true, they will be preserved at least as special cases or approximations. Thus Newtonian mechanics, though strictly false, except at the limit where spacetime is flat (and, to betechnical, the velocity of light is inifinite_, is preserved rather than discarded, as phlogiston theory of Aristotlean physic was discarded, because it is good enough for most purposes, and a lot earier to use for building bridges or launching rockets than relativistic physics. Most of the relativistic effect aren't significantly detectible at low velocities or in the small regions of spacetime in which we work.
%%%%
CB: This seems to be consonant , not in conflict with , the theory of knowledge of Engels and Lenin; objective reality ( realism), relative and absolute truth ( Newtoniam physics is relatively true, no pun) , practice is the test of theory ( good enough for most purposes).