Toby Handfield has advanced a subtle form of dispositionalism that purports to reconcile the concept of causal powers with broadly Humean convictions by dissolving the requirement for objectively modal relations between powers and their manifestations. He suggests we should identify manifestations with certain types of causal processes, and identify powers with properties that are parts of their structures. The modal features of causal powers can then be explained in terms of internal relations between a power and the property of being (...) a certain type of causal process, but these relations are supervenient and do not add anything to the basic ontology. In this way, causal powers may be ‘connected’ to their manifestations without admitting objectively modal relations. I disagree with this characterisation of causal powers and its identification of manifestations with types of causal processes: I question the assumption that causal processes can be isolated in quantum physics in the way Handfield requires and confront Humean dispositionalism with the problem of individuating powers in an entangled world. (shrink)

Esfeld has proposed a minimalist ontology of nature called ‘super-Humeanism’ that purports to accommodate quantum phenomena and avoid standard objections to neo-Humean metaphysics. I argue that Esfeld’s sparse ontology has counterintuitive consequences and generates two self-undermining dilemmas concerning the nature of time and space. Contrary to Esfeld, I deny that super-Humeanism supports an ontology of microscopic particles that follow continuous trajectories through space.

Philosophers of quantum mechanics have generally addressed exceedingly simple systems. Laura Ruetsche offers a much-needed study of the interpretation of more complicated systems, and an underexplored family of physical theories, such as quantum field theory and quantum statistical mechanics, showing why they repay philosophical attention. She guides those familiar with the philosophy of ordinary QM into the philosophy of 'QM infinity', by presenting accessible introductions to relevant technical notions and the foundational questions they frame--and then develops and defends answers to (...) some of those questions. Finally, Ruetsche highlights ties between the foundational investigation of QM infinity and philosophy more broadly construed, in particular by using the interpretive problems discussed to motivate new ways to think about the nature of physical possibility and the problem of scientific realism. (shrink)

This paper argues against the proposal to draw from current research into a physical theory of quantum gravity the ontological conclusion that spacetime or spatiotemporal relations are not fundamental. As things stand, the status of this proposal is like the one of all the other claims about radical changes in ontology that were made during the development of quantum mechanics and quantum field theory. However, none of these claims held up to scrutiny as a consequence of the physics once the (...) theory was established and a serious discussion about its ontology had begun. Furthermore, the paper argues that if spacetime is to be recovered through a functionalist procedure in a theory that admits no fundamental spacetime, standard functionalism cannot serve as a model: all the known functional definitions are definitions in terms of a causal role for the motion of physical objects and hence presuppose spatiotemporal relations. (shrink)

I argue that, just like causal explanation requires laws of nature, so metaphysical explanation requires laws of metaphysics. I offer a minimal rendition of the argument for laws of metaphysics, assuming nothing about grounding or essences, and little about explanation. And I offer a positive and minimal functional conception of the laws of metaphysics, coupled with an argument that some laws of metaphysics are fundamental.

In _Form, Matter, Substance_, Kathrin Koslicki defends a hylomorphic analysis of concrete particular objects (e.g., living organisms). The Aristotelian doctrine of hylomorphism holds that those entities that fall under it are compounds of matter (hulē) and form (morphē or eidos). Koslicki argues that a hylomorphic analysis of concrete particular objects is well-equipped to compete with alternative approaches when measured against a wide range of criteria of success. A successful application of the doctrine of hylomorphism to the special case of concrete (...) particular objects, however, hinges on how hylomorphists conceive of the matter composing a concrete particular object, its form, and the hylomorphic relations which hold between a matter-form compound, its matter and its form. Through the detailed answers to these questions Koslicki develops in this book, matter-form compounds, despite their metaphysical complexity, emerge as occupying the privileged ontological status traditionally associated with substances, due in particular to their high degree of unity. (shrink)

Many contemporary proponents of hylomorphism, the view that at least some material objects are comprised of both matter and form, endorse a version of hylomorphism according to which the form of a material object is a certain complex relation or structure. In this paper, I introduce three sorts of concerns for this “structural” approach. First, I argue that, in countenancing an abundance of overlapping yet numerically distinct material objects, “structural hylomorphists” are committed to a certain sort of systematic causal overdetermination. (...) Second, I argue that, because of its relatively thin conception of form, the view risks collapsing into some already well-entrenched metaphysical account of material objects. Finally, I argue that because the view emphasizes the more static structural features of composite material objects, structural hylomorphists seem unable to explain how it is that those objects might be said to persist over time through changes in such features. (shrink)

I develop a metaphysical position that is both lawless and anti-Humean. The position is called realist lawlessness and contrasts with both Humean lawlessness and nomological realism – the claim that there are laws in nature. While the Humean view also allows no laws, realist lawlessness is not Humean because it accepts some necessary connections in nature between distinct properties. Realism about laws, on the other hand, faces a central dilemma. Either laws govern the behaviour of properties from the outside or (...) from the inside. If the former, an unacceptable quidditist view of properties follows. But no plausible account of laws within properties can be developed that permits a governing role specifically for laws. I conclude in favour of eliminativism about laws. At the conceptual core, the notion of a law in nature is misleading. It is suggestive of an otherwise static world in need of animation. (shrink)

William Jaworski shows how hylomorphism can be used to solve mind-body problems--the question of how thought, feeling, perception, and other mental phenomena fit into the physical world. Hylomorphism claims that structure is a basic ontological and explanatory principle, and is responsible for individuals being the kinds of things they are, and having the powers or capacities they have. From a hylomorphic perspective, mind-body problems are byproducts of a worldview that rejects structure, and which lacks a basic principle which distinguishes the (...) parts of the physical universe that can think, feel, and perceive from those that can't. Without such a principle, the existence of those powers in the physical world can start to look inexplicable and mysterious. But if mental phenomena are structural phenomena then they are uncontroversially part of the physical world. Hylomorphism thus provides an elegant way of solving mind-body problems. (shrink)

Any empirical physical theory must have implications for observable events at the scale of everyday life, even though that scale plays no special role in the basic ontology of the theory itself. The fundamental physical scales are microscopic for the “local beables” of the theory and universal scale for the non-local beables. This situation creates strong demands for any precise quantum theory. This paper examines those constraints, and illustrates some ways in which they can be met.

A staunch hylomorphism involves a commitment to a sparse theory of universals and a sparse theory of composite material objects, as well as to an ontology of fundamental causal powers. Faint-hearted hylomorphism, in contrast, lacks one or more of these elements. On the staunch version of HM, a substantial form is not merely some structural property of a set of elements—it is rather a power conferred on those elements by that structure, a power that is the cause of the generation (...) (by fusion) and persistence of a composite whole through time. Bernard Williams discussed (and rejected) a faint-hearted version of HM in 1986, and faint-hearted HM has been defended more recently by Mark Johnston (2006) and Kathrin Koslicki (2008). I defend the superiority of the staunch version, in spite of its heavier ontological commitments, as a way of accounting for a real distinction between living organisms and heaps of matter, without recourse to dualism or vitalism, and as a way of combining a powers ontology with the possibility of gunk. (shrink)

Properties sometimes attributed to the “particle” aspect of a neutron, e.g., mass and magnetic moment, cannot straightforwardly be regarded in the Bohm interpretation of quantum mechanics as localized at the hypothetical position of the particle. This is shown by examining a series of effects in neutron interferometry. A related thought-experiment also provides a variation of a recent demonstration that which-way detectors can appear to behave anomolously in the Bohm theory.

David Lewis is a natural target for those who believe that findings in quantum physics threaten the tenability of traditional metaphysical reductionism. Such philosophers point to allegedly holistic entities they take both to be the subjects of some claims of quantum mechanics and to be incompatible with Lewisian metaphysics. According to one popular argument, the non-separability argument from quantum entanglement, any realist interpretation of quantum theory is straightforwardly inconsistent with the reductive conviction that the complete physical state of the world (...) supervenes on the intrinsic properties of and spatio-temporal relations between its point-sized constituents. Here I defend Lewis's metaphysical doctrine, and traditional reductionism more generally, against this alleged threat from quantum holism. After presenting the non-separability argument from entanglement, I show that Bohmian mechanics, an interpretation of quantum mechanics explicitly recognized as a realist one by proponents of the non-separability argument, plausibly rejects a key premise of that argument. Another holistic worry for Humeanism persists, however, the trouble being the apparently holistic character of the Bohmian pilot wave. I present a Humean strategy for addressing the holistic threat from the pilot wave by drawing on resources from the Humean best system account of laws. (shrink)

The paper shows how the Bohmian approach to quantum physics can be applied to develop a clear and coherent ontology of non-perturbative quantum gravity. We suggest retaining discrete objects as the primitive ontology also when it comes to a quantum theory of space-time and therefore focus on loop quantum gravity. We conceive atoms of space, represented in terms of nodes linked by edges in a graph, as the primitive ontology of the theory and show how a non-local law in which (...) a universal and stationary wave-function figures can provide an order of configurations of such atoms of space such that the classical space-time of general relativity is approximated. Although there is as yet no fully worked out physical theory of quantum gravity, we regard the Bohmian approach as setting up a standard that proposals for a serious ontology in this field should meet and as opening up a route for fruitful physical and mathematical investigations. (shrink)

Objects and Persons presents an original theory about what kinds of things exist. Trenton Merricks argues that there are no non-living inanimate macrophysical objects -- no statues or rocks or chairs or stars -- because they would have no causal role over and above the causal role of their microphysical parts. Humans do exist: we have non-redundant causal powers. Along the way, Merricks has interesting things to say about mental causation, free will, and various philosophical puzzles. Anyone working in metaphysics (...) will enjoy this lucid and provocative book. (shrink)

Consider a circle and a pair of its semicircles. Which is prior, the whole or its parts? Are the semicircles dependent abstractions from their whole, or is the circle a derivative construction from its parts? Now in place of the circle consider the entire cosmos (the ultimate concrete whole), and in place of the pair of semicircles consider the myriad particles (the ultimate concrete parts). Which if either is ultimately prior, the one ultimate whole or its many ultimate parts?

The objects we encounter in ordinary life and scientific practice - cars, trees, people, houses, molecules, galaxies, and the like - have long been a fruitful source of perplexity for metaphysicians. The Structure of Objects gives an original analysis of those material objects to which we take ourselves to be committed in our ordinary, scientifically informed discourse. Koslicki focuses on material objects in particular, or, as metaphysicians like to call them "concrete particulars", i.e., objects which occupy a single region of (...) space-time at each time at which they exist and which have a certain range of properties that go along with space-occupancy, such as weight, shape, color, texture, and temperature. The Structure of Objects focuses in particular on the question of how the parts of such objects, assuming that they have parts, are related to the wholes which they compose. (shrink)

A modest proposal concerning laws, counterfactuals, and explanations - - Why be Humean? -- Suggestions from physics for deep metaphysics -- On the passing of time -- Causation, counterfactuals, and the third factor -- The whole ball of wax -- Epilogue : a remark on the method of metaphysics.

This is a study of a crucial and controversial topic in metaphysics and the philosophy of science: the status of the laws of nature. D. M. Armstrong works out clearly and in comprehensive detail a largely original view that laws are relations between properties or universals. The theory is continuous with the views on universals and more generally with the scientific realism that Professor Armstrong has advanced in earlier publications. He begins here by mounting an attack on the orthodox and (...) sceptical view deriving from Hume that laws assert no more than a regularity of coincidence between instances of properties. In doing so he presents what may become the definitive statement of the case against this position. Professor Armstrong then goes on to establish his own theory in a systematic manner defending it against the most likely objections, and extending both it and the related theory of universals to cover functional and statistical laws. This treatment of the subject is refreshingly concise and vivid: it will both stimulate vigorous professional debate and make an excellent student text. (shrink)

The quantum theory of de Broglie and Bohm solves the measurement problem, but the hypothetical corpuscles play no role in the argument. The solution finds a more natural home in the Everett interpretation.

On the now dominant Quinean view, metaphysics is about what there is. Metaphysics so conceived is concerned with such questions as whether properties exist, whether meanings exist, and whether numbers exist. I will argue for the revival of a more traditional Aristotelian view, on which metaphysics is about what grounds what. Metaphysics so revived does not bother asking whether properties, meanings, and numbers exist (of course they do!) The question is whether or not they are fundamental.

Bohmian mechanics and the Ghirardi-Rimini-Weber theory provide opposite resolutions of the quantum measurement problem: the former postulates additional variables (the particle positions) besides the wave function, whereas the latter implements spontaneous collapses of the wave function by a nonlinear and stochastic modification of Schrödinger's equation. Still, both theories, when understood appropriately, share the following structure: They are ultimately not about wave functions but about 'matter' moving in space, represented by either particle trajectories, fields on space-time, or a discrete set of (...) space-time points. The role of the wave function then is to govern the motion of the matter. (shrink)

The aim of this essay is to distinguish and analyze several difficulties confronting attempts to reconcile the fundamental quantum mechanical dynamics with Born''s rule. It is shown that many of the proposed accounts of measurement fail at least one of the problems. In particular, only collapse theories and hidden variables theories have a chance of succeeding, and, of the latter, the modal interpretations fail. Any real solution demands new physics.

We outline Ladyman's 'metaphysical' or 'ontic' form of structuralrealism and defend it against various objections. Cao, in particular, has questioned theview of ontology presupposed by this approach and we argue that by reconceptualisingobjects in structural terms it offers the best hope for the realist in thecontext of modern physics.

It is generally argued that if the wave-function in the de Broglie–Bohm theory is a physical field, it must be a field in configuration space. Nevertheless, it is possible to interpret the wave-function as a multi-field in three-dimensional space. This approach hasn’t received the attention yet it really deserves. The aim of this paper is threefold: first, we show that the wave-function is naturally and straightforwardly construed as a multi-field; second, we show why this interpretation is superior to other interpretations (...) discussed in the literature; third, we clarify common misconceptions. (shrink)

A major disagreement between different views about the foundations of quantum mechanics concerns whether for a theory to be intelligible as a fundamental physical theory it must involve a ‘primitive ontology’ (PO), i.e. variables describing the distribution of matter in four-dimensional space–time. In this article, we illustrate the value of having a PO. We do so by focusing on the role that the PO plays for extracting predictions from a given theory and discuss valid and invalid derivations of predictions. To (...) this end, we investigate a number of examples based on toy models built from the elements of familiar interpretations of quantum theory. (shrink)

The article sets out a primitive ontology of the natural world in terms of primitive stuff—that is, stuff that has as such no physical properties at all—but that is not a bare substratum either, being individuated by metrical relations. We focus on quantum physics and employ identity-based Bohmian mechanics to illustrate this view, but point out that it applies all over physics. Properties then enter into the picture exclusively through the role that they play for the dynamics of the primitive (...) stuff. We show that such properties can be local, as well as holistic, and discuss two metaphysical options to conceive them, namely, Humeanism and modal realism in the guise of dispositionalism. 1 Introduction2 Primitive Ontology: Primitive Stuff3 The Physics of Matter as Primitive Stuff4 The Humean Best System Analysis of the Dynamical Variables5 Modal Realism about the Dynamical Variables6 Conclusion. (shrink)

This paper argues for a broadly dispositionalist approach to the ontology of Bohmian mechanics . It first distinguishes the ‘minimal’ and the ‘causal’ versions of Bohm’s theory, and then briefly reviews some of the claims advanced on behalf of the ‘causal’ version by its proponents. A number of ontological or interpretive accounts of the wave function in BM are then addressed in detail, including configuration space, multi-field, nomological, and dispositional approaches. The main objection to each account is reviewed, namely the (...) ‘problem of perception’, the ‘problem of communication’, the ‘problem of temporal laws’, and the ‘problem of under-determination’. It is then shown that a version of dispositionalism overcomes the under-determination problem while providing neat solutions to the other three problems. A pragmatic argument is thus furnished for the use of dispositions in the interpretation of the theory more generally. The paper ends in a more speculative note by suggesting ways in which a dispositionalist interpretation of the wave function is in addition able to shed light upon some of the claims of the proponents of the causal version of BM. (shrink)

Following the lead of Gustav Bergmann ( 1967 ), if not his precise terminology, ontologies are sometimes divided into those that are ‘relational’ and those that are ‘constituent’ (Wolterstorff 1970 ). Substance ontologies in the Aristotelian tradition are commonly thought of as being constituent ontologies, because they typically espouse the hylemorphic dualism of Aristotle ’s Metaphysics – a doctrine according to which an individual substance is always a combination of matter and form. But an alternative approach drawing more on the (...) fourfold ontological scheme of Aristotle’s Categories is not committed to this doctrine and may regard individual (or ‘primary’) substances as having no constituent structure, their only possible complexity residing in their possession, in some cases, of a multiplicity of substantial parts. However, as we shall see, this does not imply that such an ontology falls instead into the relational camp: for although it invokes, in addition to the category of individual substance, also those of substantial kind (‘secondary’ substance), attribute, and mode (or ‘individual accident’), it need not and arguably should not take there to be external relations between entities in the different categories. On this view, truths of exemplification and instantiation, such as ‘Dobbin is white’ and ‘Dobbin is a horse’, do not need relational truthmakers. Hence, it can be maintained that there are no such relations as ‘exemplification’ and ‘instantiation’, at most only certain relational truths of exemplification and instantiation – truths whose logical form is relational. Th is being so, I shall argue, such an ontology cannot fairly be classified as a ‘relational’ one. (shrink)

My goal in this paper is to provide characterizations of matter, form and constituency in a way that avoids what I take to be the three main drawbacks of other hylomorphic theories: (i) commitment to the universal-particular distinction; (ii) commitment to a primitive or problematic notion of inherence or constituency; (iii) inability to identify viable candidates for matter and form in nature, or to characterize them in terms of primitives widely regarded to be intelligible.

This book explains, in simple terms, with a minimum of mathematics, why things can appear to be in two places at the same time, why correlations between simultaneous events occurring far apart cannot be explained by local mechanisms, and why, nevertheless, the quantum theory can be understood in terms of matter in motion. No need to worry, as some people do, whether a cat can be both dead and alive, whether the moon is there when nobody looks at it, or (...) whether quantum systems need an observer to acquire definite properties. The author's inimitable and even humorous style makes the book a pleasure to read while bringing a new clarity to many of the longstanding puzzles of quantum physics. (shrink)

According to the doctrine of Super-Humeanism, the world’s mosaic consists only of permanent matter points and changing spatial relations, while all the other entities and features figuring in scientific theories are nomological parameters, whose role is merely to build the best law system. In this paper, I develop an argument against Super-Humeanism by pointing out that it is vulnerable to and does not have the resources to solve the well-known problem of immanent comparisons. Firstly, I show that it cannot endorse (...) a fundamentalist solution à la Lewis, since its two pillars—a minimalist ontology and a best system account of lawhood—would generate, together, a tedious problem of internal coherence. Secondly, I consider anti-fundamentalist strategies, proposed within Humeanism, and find them inapplicable to the Super-Humean doctrine. The concern is that, since it is impossible to choose the best law system within Super-Humeanism, this doctrine may be charged with incoherence. (shrink)

To understand Aristotle’s conception of form, we have to see clearly the relationship between his account and Plato’s Theory of Forms. I offer a novel interpretation of Aristotle’s Moderate Realism, in which forms are simple particulars that ground the character and mutual similarity of the entities they inform. Such an account has advantages in three areas: explaining (1) the similarity of particulars, (2) the synchronic unity of composite particulars, and (3) the diachronic unity or persistence of intrinsically changing particulars.

How should we understand the relationship, for Aristotle, between matter, form, and hylomorphic composite? Are matter and form distinct from each other, so that each hylomorphic unity harbours a plurality within it, or would such a plurality undermine the unity of the composite? A recent strand of argument in both Aristotelian and contemporary literature on hylomorphism has concluded that no genuine unity can be composed of a plurality. I will argue that the objection motivating this conclusion falls away as improperly (...) formulated in light of Aristotle's metaontology—in particular, his thesis that unity is indeterminate. The genuine objection threatening hylomorphic unity is one that Aristotle himself formulates as a central concern in his Metaphysics: no substance can be composed of substances. He answers this genuine objection in his appeal to the actuality/potentiality distinction, and in Metaphysics VIII.6 he reminds us why no more basic problem of hylomorphic unity arises. Against the backdrop of Aristotle's metaontology, hylomorphic unity cannot be undermined by the plurality, just as such, of matter and form. (shrink)

The paper compares dispositionalism about laws of nature with primitivism. It argues that while the distinction between these two positions can be drawn in a clear-cut manner in classical mechanics, it is less clear in quantum mechanics, due to quantum non-locality. Nonetheless, the paper points out advantages for dispositionalism in comparison to primitivism also in the area of quantum mechanics, and of contemporary physics in general.

We consider the possibility that all particles in the world are fundamentally identical, i.e., belong to the same species. Different masses, charges, spins, flavors, or colors then merely correspond to different quantum states of the same particle, just as spin-up and spin-down do. The implications of this viewpoint can be best appreciated within Bohmian mechanics, a precise formulation of quantum mechanics with particle trajectories. The implementation of this viewpoint in such a theory leads to trajectories different from those of the (...) usual formulation, and thus to a version of Bohmian mechanics that is inequivalent to, though arguably empirically indistinguishable from, the usual one. The mathematical core of this viewpoint is however rather independent of the detailed dynamical scheme Bohmian mechanics provides, and it amounts to the assertion that the configuration space for N particles, even N “distinguishable particles,” is the set of all N -point subsets of physical 3-space. (shrink)

There is much to admire in this book. As a rigorous and systematic physics-oriented presentation of an austere empiricist fundamental metaphysics, it has no real rivals. The clarity with which the overall vision is presented will provide a valuable stalking-horse for those who would defend less austere approaches in the future. Esfeld and Deckert never shy away from the radical consequences of their approach, or try to disguise its revisionary nature. I also found several points of agreement with Esfeld and (...) Deckert’s metaphysical outlook. In particular, I thought their form of structural realism sophisticated and plausible and their application of it to contemporary physics salutary. Fundamental metaphysics would be a more respectable discipline if all of its exponents felt the need to show how their preferred ontology plays out in the context of real physics. These points of agreement noted, I will concentrate in these comments on points where I disagree with Esfeld and Deckert. From my perspective, the metaphysical project of the book is subject to two serious objections: firstly, it remains insufficiently naturalistic and overly a prioristic, and secondly, it drains much of the explanatory power out of fundamental physics. (shrink)

If a classical system has infinitely many degrees of freedom, its Hamiltonian quantization need not be unique up to unitary equivalence. I sketch different approaches (Hilbert space and algebraic) to understanding the content of quantum theories in light of this non‐uniqueness, and suggest that neither approach suffices to support explanatory aspirations encountered in the thermodynamic limit of quantum statistical mechanics.

We show that the Bohmian approach in terms of persisting particles that move on continuous trajectories following a deterministic law can be literally applied to quantum field theory. By means of the Dirac sea model—exemplified in the electron sector of the standard model neglecting radiation—we explain how starting from persisting particles, one is led to standard QFT employing creation and annihilation operators when tracking the dynamics with respect to a reference state, the so-called vacuum. Since on the level of wave (...) functions, both formalisms are mathematically equivalent, this proposal provides for an ontology of QFT that includes a dynamics of individual processes, solves the measurement problem, and explains the appearance of creation and annihilation events. 1Bohmian Mechanics from Quantum Mechanics to Quantum Field Theory2The Dirac Sea Model3Equilibrium States and the Vacuum4Excitations of the Vacuum and the Fock Space Formalism5The Appearance of Particle Creations and Annihilations6The Merits of the Bohmian Approach. (shrink)

In this paper, it is argued that Aristotelian hylomorphism can supply a useful and informative account of composite entities as these are described by physical theory. In particular, a hylomorphic account of quantum entangled systems is defined in detail, and compared to other alternatives currently on offer—in particular, ontic structural realism. In closing, it is suggested that the view of entanglement outlined here meshes well with a recently proposed ‘coherentist’ conception.