The aim of this paper is twofold. In the first part, it clarifies the nature of wave function within the framework of the primitive ontology approach to quantum mechanics using the tools of ontic structural realism. In the second part, it critically discusses the primitive ontological move of postulating from the start matter localized in spacetime as the ultimate referent for quantum theory, in particular the case where the latter is applied to the general relativistic gravitational field.
The aim of this paper is twofold. In the first part, it clarifies the nature of wave function within the framework of the primitive ontology approach to quantum mechanics using the tools of ontic structural realism. In the second part, it critically discusses the primitive ontological move of postulating from the start matter localized in spacetime as the ultimate referent for quantum theory, in particular the case where the latter is applied to the general relativistic gravitational field.
Abstract Ontic structuralism or ontic structural realism in the philosophy of physics can be broadly considered as an interpretative strategy providing a set of conceptual and metaphysical tools—or, more ambitiously, an ontological framework—in order to account for central features of current fundamental physics. This article aims to review the main structuralist interpretative moves in the context of our two best fundamental physical theories of matter and spacetime, namely, quantum theory (quantum mechanics and quantum field theory) and general relativity. We highlight in particular the structuralist understanding of permutation invariance, entanglement and nonlocality in quantum theory, and of the dynamical features of spacetime, (gauge‐theoretic) diffeomorphism invariance and background independence in general relativity.
The aim of this paper is to summarize a particular approach of doing \nmetaphysics through physics - the primitive ontology approach. The idea is that any \nfundamental physical theory has a well-defined architecture, to the foundation of which \nthere is the primitive ontology, which represents matter. According to the framework \nprovided by this approach when applied to quantum mechanics, the wave function is not \nsuitable to represent matter. Rather, the wave function has a nomological character, given that its role in the theory is to implement the law of evolution for the primitive ontology.
Primitive ontology is a program which seeks to make explicit the ontological commitments of physical theories in terms of a distribution of matter in ordinary space-time. This program targets wave-function realism, which interprets the high-dimensional configuration space on which wave-functions are defined as our fundamental physical space. Wave-function realism allegedly fails to account for a correspondence between the ontology it postulates and the ‘manifest image’ of the world in which experimental tests of the theory are performed, and therefore the wave-function must be completed with an additional structure which describes what fundamentally exists in ordinary space-time: the ‘primitive ontol- ogy’. However primitive ontologies face some difficulties, in particular concerning the ontological status of the wave-function. In this paper, I defend a realist inter- pretation of the wave-function as describing objects in ordinary space-time, which does not require supplementing the theory with additional structure. The main dif- ference between this proposal and other primitive ontology proposals is that the fundamental constituents of reality are not conceived of as localised objects, but as primitive relations. This interpretation purports to share the advantages of both wave-function realism and primitive ontologies without facing the same difficulties. I argue that the need for an additional structure stems from a commitment to the locality of the fundamental constituents of reality, and that such commitment is unnecessary for recovering the manifest image of the world.
The meaning of the wave function has been a hot topic of debate since the early days of quantum mechanics. Recent years have witnessed a growing interest in this long-standing question. Is the wave function ontic, directly representing a state of reality, or epistemic, merely representing a state of (incomplete) knowledge, or something else? If the wave function is not ontic, then what, if any, is the underlying state of reality? If the wave function is indeed ontic, then exactly what physical state does it represent? In this book, I aim to make sense of the wave function in quantum mechanics and find the ontological content of the theory. The book can be divided into three parts. The first part addresses the question of the nature of the wave function (Chapters 1-5). After giving a comprehensive and critical review of the competing views of the wave function, I present a new argument for the ontic view in terms of protective measurements. In addition, I also analyze the origin of the wave function by deriving the free Schroedinger equation. The second part analyzes the ontological meaning of the wave function (Chapters 6, 7). I propose a new ontological interpretation of the wave function in terms of random discontinuous motion of particles, and give two main arguments supporting this interpretation. The third part investigates whether the suggested quantum ontology is complete in accounting for our definite experience and whether it needs to be revised in the relativistic domain (Chapters 8, 9).
The paper sides with the primitive ontology approach to quantum physics, as exemplified notably in Bohmian mechanics. It argues that the objects of the primitive ontology of quantum physics are structurally individuated by the spatial relations in which they stand. They neither have a primitive thisness (haecceity) nor intrinsic properties (such as mass or charge), but only stand in spatial relations. These relations make it that they are physical objects. Furthermore, in virtue of these relations, they are individuals, being absolutely discernible. Ontic structural realism thus plays a twofold role in the philosophy of quantum physics: it comes in not only at the level of the dynamics (structures of entanglement), but already at the level of the objects (primitive ontology) that instantiate the structures of entanglement, these objects being individuated by spatial relations.
According to scientific realism, science gives us an approximately true description of what the world is like. But what does it mean? In this chapter, we focus on the ontological and metaphysical aspects of this discussion. That is, we are concerned with the following questions: what there is, according to our best scientific theories? And how are these things that theories say exist? We start from the assumption that a genuine scientific realism must deal with these issues. Taking non-relativistic quantum mechanics as a case study, we discuss some of the challenges currently faced by a genuinely realistic stance. We argue, first, that in the ontological aspect, realists are in the same boat as science, that is, without sufficient epistemic justification to adopt the belief in the entities postulated by a single quantum theory, given that experience (currently) is not able to decide between rival theories; in the metaphysical aspect, realists also encounter problems with theory choice, given the possibility of associating more than one metaphysical theory with the description of the entities postulated by each quantum theory. The same goes for structuralist alternatives, since, even if we accept that scientific theories are committed to the existence of structures, but not objects, we still do not know what structures are, metaphysically. Finally, we move forward in the discussion with the meta-Popperian method, which serves to reduce the metaphysical alternatives associated with the ontological postulates of scientific theories. We may not know what the correct alternative is, but we have been able to progressively check which metaphysical alternatives are incompatible with each scientific theory.