ABSTRACT
Any theory whatsoever which, in all circumstances, attributes definite properties to non-interacting physical objects necessarily violates some of the predictions of quantum mechanics. The very existence of the hidden variables theories should, however, prompt to have a second look at the problem. The theory necessarily implies the existence of a violent nonlocality effect which, as a matter of fact, may reasonably be considered as similar to—and even more surprising than—the nonseparability of the orthodox theory. The simultaneous existence of non-separability effects and of the principle that the velocity of propagation of interactions is finite raises nontrivial conceptual problems. One possible way to study these problems is to make use of the fact that hidden variables theories exist which reproduce correctly the verifiable predictions of quantum mechanics. For the ensembles the expectation values coincide, of course, with the observed value.
