Abstract Primitive ontology (PO) approaches to quantum theory aim to describe the world in terms of matter distributed in 3-space (the PO). David Albert argues they cannot recover macroscopic structure without ad hoc coarse-graining (“squinting”). This paper formalises a Macro-Object Problem for the PO-approach based on Albert’s critique and enlists Contextual Bohmian Mechanics (CBM) to offer a solution. CBM augments the PO with a local context field $$\Lambda (x,t)$$ . While $$\Lambda$$ is fixed, the wavefunction $$\Psi$$ evolves unitarily and the particles Q follow a Bohmian guidance law; when $$\Lambda$$ changes on a bounded region R , a local completely positive instrument updates the state, with open-system energy bookkeeping and statistical locality outside R . I show that $$\Lambda$$ tiles spacetime into macro-object tokens, modulates the dynamics to confer genuine causal powers, and does so entirely within 3-space—thereby satisfying all the conditions for solving the Macro-Object Problem. I argue that physical objects are hylomorphic composites of both matter (hylē) and form (morphē), with matter corresponding to the particles and $$\Lambda$$ serving as a rigorous surrogate for local form.
Abstract Primitive ontology (PO) approaches to quantum theory aim to describe the world in terms of matter distributed in 3-space (the PO). David Albert argues they cannot recover macroscopic structure without ad hoc coarse-graining (“squinting”). This paper formalises a Macro-Object Problem for the PO-approach based on Albert’s critique and enlists Contextual Bohmian Mechanics (CBM) to offer a solution. CBM augments the PO with a local context field Λ(x,t) . While Λ is fixed, the wavefunction Ψ evolves unitarily and the particles Q follow a Bohmian guidance law; when Λ changes on a bounded region R , a local completely positive instrument updates the state, with open-system energy bookkeeping and statistical locality outside R . I show that Λ tiles spacetime into macro-object tokens, modulates the dynamics to confer genuine causal powers, and does so entirely within 3-space—thereby satisfying all the conditions for solving the Macro-Object Problem. I argue that physical objects are hylomorphic composites of both matter (hylē) and form (morphē), with matter corresponding to the particles and Λ serving as a rigorous surrogate for local form.
Abstract The primitive ontology approach to quantum mechanics seeks to account for quantum phenomena in terms of a distribution of matter in three-dimensional space (or four-dimensional spacetime) and a law of nature that describes its temporal development. This approach to explaining quantum phenomena is compatible with either a Humean or powerist account of laws. In this paper, I offer a powerist ontology in which the law is specified by Bohmian mechanics for a global configuration of particles. Unlike in other powerist ontologies, however, this law is not grounded in a structural power that is instantiated by the global configuration. Instead, I combine the primitive ontology approach with Aristotle’s doctrine of hylomorphism to create a new metaphysical model, in which the cosmos is a hylomorphic substance with an intrinsic power to choreograph the trajectories of the particles.
ABSTRACT This article surveys recent work on primitive ontology (PO) approaches to quantum mechanics, focusing on proposals that seek to integrate this approach with the metaphysics of causal powers. PO approaches aim to provide a clear metaphysical picture in which the world consists of local entities such as particles, matter density fields or flashes, and these entities compose macroscopic objects, such as scientists and their measuring devices. To account for the behaviour of these local entities, some PO theories invoke the metaphysics of powers. After motivating PO approaches and contrasting them with wave function realism, I consider the development of power‐based POs, contrasting them with both Humean POs and POs which invoke primitive laws. I explain how different power‐based frameworks address key quantum phenomena, and I survey some difficulties, including the Problem of Holism, of small worlds and of top‐down causation. Such challenges are best confronted, I suggest, by drawing on Aristotelian hylomorphism: If powers are grounded in forms that unify physical systems, then power‐based POs can accommodate holistic and context‐sensitive behaviour.
Abstract We propose an extension of Bell-type Bohmian quantum field theories, called Contextual Bohmian Quantum Field Theory (CBQFT), which integrates micro-level dynamics and macro-level contextual structure within a unified, ontologically explicit formalism. CBQFT introduces classical variables Λ that encode macroscopic contexts—such as detector configurations, thermal phases, or symmetry-breaking sectors—and allows these to modulate the underlying quantum dynamics in a lawlike way. We develop two versions of the model. CBQFT-1 treats context as a fixed but dynamically influential background, entering via a context-sensitive Hamiltonian and modified Bell-type jump rates on a single Fock space. CBQFT-2 upgrades context to a dynamical variable co-evolving with the particle (or field) configuration: Λ(x,t) selects a (typically inequivalent) representation of the field algebra on a Hilbert space, wavefunctions are realised as global sections of the resulting Hilbert bundle, and Bohmian trajectories are guided by globally well-defined velocity fields constructed from local currents. Context transitions in CBQFT-2 are governed by a stochastic kernel informed by particle (or field) configurations and histories. This yields a Bohmian QFT with an explicit feedback loop between quantum events and macroscopic structure, offering a hylomorphic account of measurement, decoherence, and top–down causation.
Abstract The Problem of Macro-Objects concerns how three-dimensional, middle-sized objects, such as scientists and their measuring devices, can exist in a quantum world. This paper discusses the problem for wave function realism and the primitive ontology approach to quantum mechanics, focussing on Alyssa Ney’s recent two-stage solution, in which macro-objects are functionally reduced to micro-objects and micro-objects are parts of a whole in which they are grounded (the wave function field). It raises metaphysical difficulties with this proposal which a hylomorphic account of wholes may be able to address, noting possible implications for one’s philosophy of mind depending on one’s preferred solution to the Measurement Problem.
The wave function of quantum mechanics can be understood in terms of the dispositional role it plays in the dynamics of a distribution of matter in three-dimensional space (or four-dimensional spacetime). There is more than one way, however, of specifying its dispositional role. This paper considers Suárez’s theory of ‘Bohmian dispositionalism’, in which the particles are endowed with their own ‘Bohmian dispositions’, and Simpson’s theory of ‘Cosmic Hylomorphism’, in which the particle configuration comprises a hylomorphic substance which has an intrinsic power. I argue that Bohmian dispositionalism fails to capture intuitively correct counterfactuals about what would happen in Small Worlds which have only a small number of particles, but that this problem is avoided by Cosmic Hylomorphism, in which the cosmic power manifests a teleological process.
This thesis develops a detailed account of the emergence of for all practical purposes continuous, quasi-classical world histories from the discontinuous, stochastic micro dynamics of Minimal Bohmian Mechanics (MBM). MBM is a non-relativistic quantum theory. It results from excising the guiding equation from standard Bohmian Mechanics (BM) and reinterpreting the quantum equilibrium hypothesis as a stochastic guidance law for the random actualization of configurations of Bohmian particles. On MBM, there are no continuous trajectories linking up individual configurations. Instead, individual configurations are actualized independently of each other, carving out the decoherence-induced branching structure of the universal wave function. Yet, by contrast to the Everett interpretation, branches of the universal wave function are not actualized in parallel, i.e. all at the same time. Rather, world branches, on MBM, are actualized sequentially. For an introduction to MBM, the transition from BM to MBM is described, and their empirical equivalence is established. I present the conditions under which MBM can be classified as a primitive ontology (PO) theory, regarded as crucial for the acceptance of a theory as Bohmian by many proponents of BM. While rendering MBM compatible with the PO approach, it must not fall prey to the problem of communication, arising from the two-space reading of BM. The issue of temporal solipsism, identified by Bell as a serious problem for his “Everett (?) theory” – the historic predecessor of MBM – is discussed. I argue that Barbour’s time capsule approach does not provide a satisfactory solution. In particular, his adopting a more than minimal psychophysical parallelism between brain processes and experience of macroscopic change is argued to be reasonable in light of our current best neuroscience, yet problematic for theories relying solely on time capsules, understood as highly structured, individual, internally static configurations. As a solution, I introduce worlds, and world histories, as key concepts in providing a link between MBM’s micro dynamics and macroscopic phenomena. Worlds, other than time capsules, are coarse-grained regions in phase- or configuration space, defined as sets of possible micro states satisfying a relation of sufficient similarity from a macroscopic perspective, with respect to a given micro state. Hence, worlds may overlap. I argue that worlds thus construed are a reasonable option for replacing the disjoint macro regions of phase space, resulting from the usual way of partitioning phase space in the standard framework of Boltzmannian statistical mechanics. This move solves the issue of discontinuous change of macro variables upon the micro state crossing the boundary between different macro regions. I adapt this move for MBM’s discontinuous micro dynamics in configuration space. Issues revolving around the microscopic-macroscopic distinction, particle identity, impenetrability and haecceity in light of the desideratum of particle number conservation, etc., are discussed. I provide a detailed explanation of how overlapping worlds in MBM form world histories, thereby linking up macroscopically distinct worlds. Thus, the problem of temporal solipsism is resolved in a way that is compatible with a more than minimal psychophysical parallelism.