Backward causation, hidden variables and the meaning of completeness

Bell's theorem requires the assumption that hidden variables are independen t of future measurement settings. This independence assumption rests on sur prisingly shaky ground. In particular, it is puzzlingly time-asymmetric. Th e paper begins with a summary of the case for considering hidden variable m odels which, in abandoning this independence assumption, allow a degree of 'backward causation'. The remainder of the paper clarifies the physical sig nificance of such models, in relation to the issue as to whether quantum me chanics provides a complete description of physical reality.