Chakravartty and others have pressed that the defender of scientific realism needs to supply a metaphysical story, most saliently a modal story, of how knowledge of the unobservable can be possible. Here I consider the challenge the problem of theory change poses to theories of modal metaphysics.

Non-Humean accounts of the metaphysics of nature posit either laws or powers in order to account for natural necessity and world-order. We argue that such monistic views face fundamental problems. On the one hand, neo-Aristotelians cannot give unproblematic power-based accounts of the functional laws among quantities offered by physical theories, as well as of the place of conservation laws and symmetries in a lawless ontology; in order to capture these characteristics, commitment to governing laws is indispensable. On the other hand, (...) ontologies that entirely exclude some kind of power ascription to worldly entities face what we call the Governing Problem: such ontologies do not have the resources to give an adequate account of how laws play their governing role. We propose a novel dualist model, which, we argue, has the resources to solve the difficulties encountered by its two dominant competitors, without inheriting the problems of either view. According to the dualist model, both laws and powers are equally fundamental and irreducible to each other, and both are needed in order to give a satisfactory account of the nomological structure of the world. The dualist model constitutes thus a promising alternative to current monistic views in the metaphysics of science. (shrink)

Dispositional Essentialism and Ontic Structural Realism aim to account for modality. Dispositional Essentialism takes properties to account for laws. In particular, it takes determinate properties to account for laws of nature, which are determinable. Ontic Structural Realism does the reverse. According to Steven French, Ontic Structural Realism takes laws and symmetries to be part of the fundamental structure of the world. Determinate properties are “dependent” on laws. The core difference between Dispositional Essentialism and Ontic Structural Realism’s accounts of modality is (...) the direction of the dependence between properties and laws. As a result, French describes Ontic Structural Realism as a reverse-engineering of Dispositional Essentialism, and Chakravartty differentiates them by saying that Dispositional Essentialism gives a bottom-up account of modality whereas Ontic Structural Realism’s is top-down. Both views face significant problems. The main problems these views face stem from relational individuation. Properties are individuated by their relations to further properties. As such, it is hard to see how they can be metaphysically prior to those relations as per Dispositional Essentialism. Equally, laws are relations between properties. As such, it is hard to see how they could be metaphysically prior to the properties they relate as per Ontic Structural Realism. Both properties and laws seem dependent on each other. By requiring one to come first and explain the other, dispositional essentialists and ontic structural realists end up in a chicken-egg scenario. I propose a hybrid between Dispositional Essentialism and Ontic Structural Realism. My hybrid view does away with the dogma of ontological priority between properties and laws. Instead, properties and laws symmetrically depend. I argue that my hybrid view is the way out of the chicken-egg-property-law conundrum. It paves a new way for making sense of modality from a structuralist perspective. (shrink)

The composition of objects is a much discussed issue in metaphysics. In this paper I look at various approaches to this issue in the context of two examples: the relationship between ‘everyday’ objects, such as tables, and their constituent physical entities, and the relationship between structures and objects, from the perspective of structural realism. My aims are first, to defend forms of eliminativism in both cases, whereby one can still make statements about the entities to be eliminated ; and second, (...) to highlight some of the metaphysical moves that are available to the structuralist in articulating their ontology. In doing so I hope also to indicate how metaphysics and the philosophy of science can be brought into a more productive relationship. (shrink)

The paper has three parts. In the first part ExtOSR, an extended version of Ontic Structural Realism, will be introduced. ExtOSR considers structural properties as ontological primitives, where structural properties are understood as comprising both relational and structurally derived intrinsic properties or structure invariants. It is argued that ExtOSR is best suited to accommodate gauge symmetry invariants and zero value properties. In the second part, ExtOSR will be given a Humean shape by considering structures as categorical and global. It will (...) be laid out how such structures serve to reconstruct non-essential structural kinds and laws. In the third part Humean structural realism will be defended against the threat of quidditism. (shrink)

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. (shrink)