The present paper argues that the typical structuralist claims according to which invariances, symmetries and the like are fundamental – especially in physics – should not be understood in terms of physical relations being fundamental. Rather, they should be understood in terms of ‘metaphysical coherentism’ - the idea that object-like parts of reality exhibit symmetric relations of ontological dependence. The view is developed in some detail, in particular by showing that i) symmetric ontological dependence does not necessarily lead to uninformative (...) metaphysical explanations, and ii) metaphysical coherentism strikes the best balance between the requirements of naturalism and those of theoretical consistency – especially in view of the difficulties that structuralists seem to have in accounting for all state-independent properties of particles in relational terms. On this basis, the coherentist picture is applied to the interpretation of the quantum domain, and contrasted with extant varieties of structuralism, of both the eliminative and the non-eliminative sort, and holism. (shrink)

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 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, diffeomorphism invariance and background independence in general relativity. (shrink)

This is the revised version of an invited keynote lecture delivered at the "1st Australian Computing and Philosophy Conference". The paper is divided into two parts. The first part defends an informational approach to structural realism. It does so in three steps. First, it is shown that, within the debate about structural realism, epistemic and ontic structural realism are reconcilable. It follows that a version of OSR is defensible from a structuralist-friendly position. Second, it is argued that a version of (...) OSR is also plausible, because not all relata are logically prior to relations. Third, it is shown that a version of OSR is also applicable to both sub-observable and observable entities, by developing its ontology of structural objects in terms of informational objects. The outcome is informational structural realism, a version of OSR supporting the ontological commitment to a view of the world as the totality of informational objects dynamically interacting with each other. The paper has been discussed by several colleagues and, in the second half, ten objections that have been moved to the proposal are answered in order to clarify it further. (shrink)

This paper sets out a moderate version of metaphysical structural realism that stands in contrast to both the epistemic structural realism of Worrall and the—radical—ontic structural realism of French and Ladyman. According to moderate structural realism, objects and relations (structure) are on the same ontological footing, with the objects being characterized only by the relations in which they stand. We show how this position fares well as regards philosophical arguments, avoiding the objections against the other two versions of structural realism. (...) In particular, we set out how this position can be applied to space-time, providing for a convincing understanding of space-time points in the standard tensor formulation of general relativity as well as in the fibre bundle formulation. (shrink)

This paper offers a critical assessment of the current state of the debate about the identity and individuality of material objects. Its main aim, in particular, is to show that, in a sense to be carefully specified, the opposition between the Leibnizian ‘reductionist’ tradition, based on discernibility, and the sort of ‘primitivism’ that denies that facts of identity and individuality must be analysable has become outdated. In particular, it is argued that—contrary to a widespread consensus—‘naturalised’ metaphysics supports both the acceptability (...) of non-qualitatively grounded (both ‘contextual’ and intrinsic) identity and a pluralistic approach to individuality and individuation. A case study is offered that focuses on non-relativistic quantum mechanics, in the context of which primitivism about identity and individuality, rather than being regarded as unscientific, is on the contrary suggested to be preferable to the complicated forms of reductionism that have recently been proposed. More generally, by assuming a plausible form of anti-reductionism about scientific theories and domains, it is claimed that science can be regarded as compatible with, or even as suggesting, the existence of a series of equally plausible grades of individuality. The kind of individuality that prevails in a certain context and at a given level can be ascertained only on the basis of the specific scientific theory at hand. (shrink)

The determination of inertia by matter is looked at in general relativity, where inertia can be represented by affine or projective structure. The matter tensor T seems to underdetermine affine structure by ten degrees of freedom, eight of which can be eliminated by gauge choices, leaving two. Their physical meaning---which is bound up with that of gravitational waves and the pseudotensor t, and with the conservation of energy-momentum---is considered, along with the dependence of reality on invariance and of causal explanation (...) on conservation. (shrink)

After stressing how the attempt to provide a plausible account of the connection between language and the world was one of Putnam’s constant preoccupations, this article describes the four stages his thinking about the concepts of truth and reality went through. Particular attention is paid to the kinds of problems that made him abandon each stage to enter the next. The analysis highlights how all the stages but one express a general non-epistemic stance towards truth and reality—the right stance, according (...) to Putnam, in order to develop full-blooded realism. Since the last stage combines a version of direct realism with a pluralist conception of truth, the article proceeds by focusing on Putnam’s alethic pluralism, carefully distinguishing it from alethic deflationism. Finally a suggestion is made as to where Putnam’s alethic pluralism may be placed within the constellation of current pluralist positions about truth. (shrink)

1.: In this paper I discuss Putnam’s view on time and the special theory of relativity. I first locate Putnam’s philosophical approach within a more general framework, essentially making reference to Sellar’s distinction between the scientific image and the manifest image of the world. I then reconstruct Putnam’s argument in favour of the reality of the future and the determinateness of truth-value for future tense sentences by showing that it is based on three premises that generate a contradiction. In the (...) second part of the paper I discuss Putnam’s argument both by using later results belonging to the foundations of STR and quantum mechanics, and by invoking some conceptual analysis on the pseudo-predicate “is real”. Since I will show that the presentists/eternalists debate is ill-founded if regarded as ontological, I will conclude that it boils down to our different practical attitudes towards past, present and future. (shrink)