  The main problem in reconciling collapse theories with special relativity is that it seems very difficult to make state collapse (modeled as a real physical process) compatible with the structure of the Minkowski spacetime. In non-relativistic quantum mechanics, the earlier L-measurement in the EPR/B experiment induces a collapse of the entangled state of the particle pair and the L-measurement apparatus. Assuming (for the sake of simplicity) that measurement events occur instantaneously, state collapse occurs along a single spacelike hyperplane that intersects the spacetime region of the L-measurement event—the hyperplane that represents the (absolute) time of the collapse. But this type of collapse dynamics would involve a preferred foliation of spacetime, in violation of the spirit, if not the letter of the Minkowski spacetime. 