We set out a fundamental ontology of atomism in terms of matter points. While being most parsimonious, this ontology is able to match both classical and quantum mechanics, and it remains a viable option for any future theory of cosmology that goes beyond current quantum physics. The matter points are structurally individuated: all there is to them are the spatial relations in which they stand; neither a commitment to intrinsic properties nor to an absolute space is required. The spatial relations change. All that is needed to capture change is a dynamical structure, namely dynamical relations as expressed in terms of the dynamical parameters of a physical theory.
We set out a fundamental ontology of atomism in terms of matter points. While being most parsimonious, this ontology is able to match both classical and quantum mechanics, and it remains a viable option for any future theory of cosmology that goes beyond current quantum physics. The matter points are structurally individuated: all there is to them are the spatial relations in which they stand; neither a commitment to intrinsic properties nor to an absolute space is required. The spatial relations change. All that is needed to capture change is a dynamical structure, namely dynamical relations as expressed in terms of the dynamical parameters of a physical theory.
As far as classical physics is concerned, it is possible to trace causal relations between physical objects (i.e. particles in this case) back to intrinsic properties of these objects (such as their mass and charge). On this view, causal relations turn out to be internal instead of external relations, supervening on intrinsic properties of the relata (as proposed by Heil and Lowe). However, one can raise doubts about this view already in Newtonian mechanics. The decisive blow to this view comes from quantum physics, with Bell’s theorem proving that no dynamics based on local, intrinsic properties of quantum objects can yield the empirical predictions of quantum mechanics. Nonetheless, quantum entanglement by no means implies that we have to abandon an ontology of objects (i.e. substances such as particles) in favour of an ontology of structures (as claimed by French and Ladyman). Any of the known proposals for a quantum ontology of matter in space-time is committed to objects. However, on any of these proposals, what determines the dynamics of these objects are not local, intrinsic properties, but a global or holistic property instantiated by all the objects together – that is, a structure that takes all the objects in the universe as its relata. The view set out in this paper thus amounts to combining ontic structural realism with an ontology of objects that can be conceived as substances. This suggestion is illustrated by drawing on the ontology of quantum physics worked out by Bohm and Bell. 1.
The paper sketches out an ontology of physics in terms of matter being primitive stuff distributed in space and all the properties physics is committed to being dispositions that fix the temporal development of the distribution of matter in space. Whereas such properties can be conceived as intrinsic properties of particles in classical mechanics, in quantum physics, there is a holistic property or structure that relates all matter and that fixes its temporal development. 1. Classical physics and intrinsic properties At the end of the “Opticks ” (1704), Newton writes: … it seems probable to me, that God in the Beginning form’d Matter in solid, massy, hard, impenetrable, moveable Particles …; no ordinary Power being able to divide what God himself made one in the first Creation. … the Changes of corporeal Things are to be placed only in the
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.
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.
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 Super-Humean strategy is a purely philosophical one: in a nutshell, on this strategy, there is a relationalist ontology, but a non-relationalist physical theory. When it comes to quantum mechanics, a discussion of ontology makes sense only if one spells out to which version of the quantum mechanics one is committed—that is, how one solves the measurement problem. The quantum theory going back to de Broglie and D. Bohm is the most prominent of them. It is based on a primitive ontology of permanent point particles as in the classical mechanics. The dynamical structure that a physical theory introduces is in any case defined for the universe as a whole. For instance, as soon as there are dynamical parameters whose value is conserved throughout the universe—such as the total energy—there are global correlations in the motions of the matter points.