Abstract

In the conflict between Albert Einstein and Niels Bohr over the fundamental nature of reality, quantum mechanics was the experimental data being interpreted. The Copenhagen school maintained, crudely speaking, that reality at the microscopic level was to some extent subjective and acausal. Einstein, on the other hand, believed that no event was without cause and proposed the famous Einstein-Podolsky-Rosen paradox attacking the conclusions of quantum mechanics as being self-contradictory. The paradox, of course, was that quantum mechanics was observed to be experimentally true.

The EPR proposal for an operational definition of reality was eminently sensible: If an event could be predicted with certainty it was real. The difficulty was that EPR did not discuss the aspect of locality. I would suggest extending their definition to read: To the extent that an event can be predicted it is locally causal; to the extent that an observed event is unpredictable it is real but only causal on a non-local scale.