Mauro Dorato

In the first part of the paper I argue that an ontology of events is precise, flexible and general enough so as to cover the three main alternative formulations of quantum mechanics as well as theories advocating an antirealistic view of the wave function. Since these formulations advocate a primitive ontology of entities living in four-dimensional spacetime, they are good candidates to connect that quantum image with the manifest image of the world. However, to the extent that some form of realism about the wave function is also necessary, one needs to endorse also the idea that the wave function refers to some kind of power. In the second part, I discuss some difficulties raised by the recent proposal that in Bohmian mechanics this power is holistically possessed by all the particles in the universe.

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and the sort of ‘primitivism’ that denies that facts of identity and individuality must be analysable has become outdated.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.

In this paper I argue that the debate between the so-called “presentists” – according to whom only the present is real – and the “eternalists”, according to whom past present and future are equally real, has no ontological significance. In particular, once we carefully distinguish between a tensed and a tenseless sense of existence, it is difficult to find a single ontological claim on which the two parties could disagree. Since the choice of using a tense or a tenseless language is dictated by purely pragmatic reasons, we should abstain from bringing to bear pseudo-debates generated by the “tensed” or the “tenseless theories” of time on the question of understanding the philosophical implications of contemporary spacetime theories, or notions like becoming, change and persistence in time.

In this essay I claim that thought experiments have invariably been very important to inquire into the foundations of natural science (in particolar physics). In particular, they have proved essential to test the stability of allegedly clear but ultimately contradictory concepts, that were nonetheless at the basis of widely shared scientific theories. By quickly reviewing some famous Gedankenexperimenten proposed by Einstein against the completeness of (Bohr’s interpretation of) quantum mechanics, I will try to ask how could they possibly have the critical role that they always had.

Debates about the ontological implications of the general theory of relativity have long oscillated between spacetime substantivalism and relationism. I evaluate such debates by claiming that we need a third option, which I refer to as “structural spacetime realism.” Such a tertium quid sides with the relationists in defending the relational nature of the spacetime structure, but joins the substantivalists in arguing that spacetime exists, at least in part, independently of particular physical objects and events, the degree of “independence” being given by the extent to which geometrical laws exist “over and above” physical events exemplifying them. By showing that structural spacetime realism is the natural outcome of a semantic, model-theoretic approach to the nature of scientific theories, I conclude by arguing that the notion of partial isomorphic representation is the most plausible candidate to connect spacetime models with reality.

The conceptual relation between objective becoming and the direction of time is explored by discussing an ontologically asymmetric notion of causation. It is claimed that such a notion, in terms of which Stein defined objective becoming in Minkowski spacetime, has either a purely metaphysical status or is reducible to physical concepts. In the former case, it is adequate for Stein's purpose but irrelevant to physical theories. In the latter, the causal asymmetry can be related to irreversible physical processes only in an extrinsic way. This dilemma creates additional difficulties both to a unified theory of the direction of time and to the project of making room for becoming in the physical world.

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.