This paper involves one crucial assumption; namely, that the statistical predictions of quantum mechanics for Bell's variant of the EPR experiment will continue to be verified as detector efficiencies are improved and the need for coincidence counters is eliminated. This assumption entails that any hidden-variables theory for quantum mechanics must violate Bell's inequality--the inequality derived in Bell (1964). It is shown here that four locality conditions are involved in the derivation of Bell's inequality; and that a violation of any of (...) the four locality conditions will either entail the existence of superluminal influences or the existence of superluminal signals (superluminal influences that can be used to transmit information), if conspiratorial theories can be ruled out. The attempts so far to rule out conspiratorial theories are all found to be rather dubious, but there are other considerations developed here that rule them out convincingly. Finally, it is demonstrated that violations of each of the four locality conditions can be used to transmit information superluminally, if certain auxiliary conditions are satisfied. This is of particular interest because one of these conditions corresponds to a condition dubbed "completeness" by Jon Jarrett. Jarrett and others have suggested that violations of completeness cannot be used to send information superluminally. Demonstrating otherwise is, perhaps, the most significant result obtained in this paper. (shrink)

http://dx.doi.org/10.5007/1808-1711.2008v12n1p49 The aim of this article is to offer a rejoinder to an argument against scientific realism put forward by van Fraassen, based on theoretical considerations regarding microphysics. At a certain stage of his general attack to scientific realism, van Fraassen argues, in contrast to what realists typically hold, that empirical regularities should sometimes be regarded as “brute facts”, which do not ask for explanation in terms of deeper, unobservable mechanisms. The argument from microphysics formulated by van Fraassen is based (...) on the claim that in microphysics the demand for explanation leads to a demand for the so-called hidden-variable theories, which “runs contrary to at least one major school of thought in twentieth-century physics”. It is shown here that this argument does not represent an insurmountable obstacle to scientific realism, not even when a series of important theoretical and experimental results against hidden-variable theories — and not merely a conflict with a certain school of thought—is taken into account. (shrink)