Nonseparability, Potentiality, and the Context-Dependence of Quantum Objects

Abstract

SUMMARY. Standard quantum mechanics undeniably violates the notion of separability that classical physics accustomed us to consider as valid. By relating the phenomenon of quantum nonseparability to the all-important concept of potentiality, we effectively provide a coherent picture of the puzzling entangled correlations among spatially separated systems. We further argue that the generalized phenomenon of quantum nonseparability implies contextuality for the production of well-defined events in the quantum domain, whereas contextuality entails in turn a structural-relational conception of quantal objects, viewed as carriers of dispositional properties. It is finally suggested that contextuality, if considered as a conditionalization preparation procedure of the object to be measured, naturally leads to a separable concept of reality whose elements are experienced as distinct, well-localized objects having determinate properties.In this connection, we find it necessary to distinguish the meaning of the term reality from the criterion of reality for us. The implications of the latter considerations for the notion of objectivity in quantum mechanics are also discussed.Key words: nonseparability, potentiality, holism, contextuality, quantum object, objectivity THE MEANING OF THE SEPARABILITY PRINCIPLE IN CLASSICAL PHYSICSClassical physics is essentially atomistic in character. It portrays a view of the world in terms of analyzable, separately existing but interacting self-contained parts. Classical physics is also reductionistic. It aims at explaining the whole of forms of physical existence, of structures and relations of the natural world in terms of a salient set of elementary material objects linked by forces. Classical physics (and practically any experimental science) is further based on the Cartesian dualism of 'res cogitans' ('thinking substance') and 'res extensa' ('extended substance'), proclaiming a radical separation of an objective external world from the knowing subject that allows no possible intermediary. * Department of Philosophy and History of Science, University of Athens, Athens 157 71, Greece (E-mail: karakost@phs.uoa.gr) 2 In fact, the whole edifice of classical physics  be it point-like analytic, statistical, or field theoretic  is compatible with the following separability principle that can be expressed schematically as follows:Separability Principle: The states of any spatio-temporally separated subsystems S 1 , S 2 , ..., S N of a compound system S are individually well-defined and the states of the compound system are wholly and completely determined by them and their physical interactions including their spatio-temporal relations (cf. Howard 1989;Healey 1991).In the case, for instance, of point-like analytic mechanics, the state of a compound system consisting of N point particles is specified by considering all pairs {q 3N (t), p 3N (t)} of the generalized position and momentum coordinates of the individual particles. Hence, at any temporal moment t, the individual pure state of...

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