Chapter Fifteen: Objectivity and Realism in Quantum Mechanics

Dennis Dieks

Bernard d’Espagnat

Michaël Esfeld

In this chapter it is argued that the decisive argument against the reducibility of causal relations comes from quantum physics. Bell’s theorem proves that no dynamics based on the local, intrinsic properties of quantum objects can yield the empirical predictions of quantum mechanics. Nonetheless, it is argued that quantum entanglement by no means implies that we have to abandon an ontology of objects in favour of an ontology of structures. All extant proposals for a quantum ontology of matter in spacetime are committed to objects, whose dynamics are determined not by their local, intrinsic properties, but by an holistic property instantiated by all the objects together—a structure that takes all the objects in the universe as its relata. The view set out in this chapter combines ontic structural realism with an ontology of objects that can be conceived as substances.

Philipp Berghofer, Harald A. Wiltsche

This chapter reexamines wave function realism (WFR) through the lens of phenomenology. We begin by situating WFR within the broader debate about the ontology of the quantum state and the temptation to "read off" metaphysics from mathematical formalism. Against this background, we turn to the London-Bauer interpretation (LBI), the most explicit attempt to interpret quantum mechanics through phenomenological categories. On this view, the measurement transition is not a physical discontinuity but a reflective articulation of objectivity, and the wave function formally encodes the horizonal structure of world-givenness. We develop this idea by reconfiguring the notion of realism itself: not as objectivist, but as correlational and transcendental. The resulting picture suggests that quantum mechanics, rather than depicting a world "minus observers," mathematically articulates the very correlation through which a world becomes manifest at all.

Arthur Jabs

Vassilios Karakostas