On Quantum Non-locality and Possible Worlds. Critical Remarks

Abstract

In 2006 Tomasz F. Bigaj published in English a book "Non-locality and the Possible Worlds. A Counterfactual Perspective on Quantum Entanglement". He considered the question whether a satisfactory interpretation of quantum mechanics in the standard form should include the assumption of a non-local, immediate influence of one part of a specific quantum system (like two electrons in the singlet state) on the other, spatially separated part of that system. Bigaj - following H. Stapp - chooses as conceptual instruments of his analysis counterfactual conditional statements and possible-worlds semantics of such statements. After thorough examination of different Stapp's arguments, he reaches the conclusion "that no matter what available interpretation of counterfactuals we decide to follow, there is no need in standard quantum mechanics for measurement-included non-locality". My critique concerns mainly Bigaj's selection of conceptual tools: the counterfactuals and possible-worlds semantics. I point to the fact that such selection assumes the "necessitarian" interpretation of laws of nature in the domain of micro-objects (e.g. for systems like two electrons in the singlet state). The different, "regularist" interpretation of physical laws in that domain is possible as well, and counterfactual arguments are not valid for such interpretation.