This can only be tested by suitable macroscopic measurements. To discriminate between the class of theories we are proposing one must use statistically irreversible macroscopic events to measure the timing. If the probability of reversal is sufficiently low the events can be treated as if they were absolutely irreversible. If necessary their probability of being reversed can be factored into the experimental analysis. Typical experiment to test Bell's inequality Reported experiments generally involve a setup such as that shown in Figure .
Most experiments are symmetric.
L is the distance from either polarizer to the closest detector. Locality demands that a change large enough to violate Bell' s inequality can only happen in the time it would take light to travel the longer distance K . K is the distance from either polarizer to the more distant detector. It is technically difficult to directly measure D and none of the reported experiments do this. Indirect arguments about D are all questionable.