Particles and Individuality in Quantum Physics: redefining object’s concept

Doctoral Dissertation uoadl:2919230 267 Read counter

Department of History and Philosophy of Science
Library of the School of Science
Deposit date:
Rousomani Kalliopi
Dissertation committee:
Ψύλλος Στάθης, Καθηγητής, ΕΚΠΑ
Δημητρακόπουλος Κώστας, Καθηγητής, ΕΚΠΑ
Πορτίδης Δημήτρης, αν. Καθηγητής, Πανεπιστήμιο Κύπρου
Στεφάνου Γιάννης, επ. Καθηγητής, ΕΚΠΑ
Χριστοδούλου Δήμητρα, επ. Καθηγήτρια, ΕΚΠΑ
Καπάνταης Δούκας, Ακαδημία Αθηνών
Λιβάνιος Βασίλης, επ. Καθηγητής, Πανεπιστήμιο Κύπρου
Original Title:
Σωματίδια και Ατομικότητα στη Κβαντική Φυσική: επαναπροσδιορίζοντας την έννοια του αντικειμένου
Translated title:
Particles and Individuality in Quantum Physics: redefining object’s concept
Quantum particles can be considered objects since quantum physics describes them as bearers of properties. Nevertheless, quantum particles exist in a way significantly different from that of classical objects, which are considered idealizations of ordinary things. For that reason, the concept of object calls for some redefinition so that it can be applied in every aspect of reality. Tracing the differences between classical and quantum particles is the first step towards this objective.
The indistinguishability of quantum particles, as recorded in the findings of statistical research of quantum systems, constitutes the main difference between quantum and classical particles, feeding the debate concerning the nature of the subatomic world. Philosophical argument has focused on Leibniz’s Principle of the Identity of Indiscernibles (PII) and both the “prevailing” and the “alternative” view have been formed with reference to it. Both the “prevailing” and the “alternative” view attribute a different normative content to PII: the “prevailing” view invokes PII as a principle of individuation, concluding that it fails to perform that role. On the other hand, the alternative view invokes PII as a principle on which the arithmetic difference of objects can be founded, concluding that among all the quantum particles only the fundamental bosons cannot be considered objects.
Nevertheless, the whole discussion overlooks the particles’ aspect of quantum particles, since it considers only superposition states where particles become indistinguishable and their individuation is metaphysically impossible. But indistinguishability is not the only way of existence for quantum particles; according to the principle of wave-particle duality, for every kind of particle there exist certain conditions under which the wave properties retreat against particle properties and then quantum particles become distinguishable and exist as individuals.
The redefinition of the concept of object must be done on the basis of the dual nature of quantum particles so that something can be an object without necessarily behaving in an individual way. To this direction, the distinction between the concepts of countability and individuality is called for: objects must always exist as countable entities and only at appropriate conditions must exist as individuals. Under this conceptualization, quantum particles can be considered both as objects and potentially as indivituals.

However, the individuation of objects under certain conditions is inconsistent with the idea of an intrinsic individuality, which is inseparable with reductionist metaphysical theories concerning objects, like bundle and substratum theories. Instead the Aristotelian theory of substance is put forward, according to which objects always exist as objects of some kind and they are individuated by kind.
Main subject category:
Other subject categories:
Philosophy - Psychology
(in)distinguishability, countability, wave/particle duality, substance theory
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