Mauro Dorato

By briefly reviewing three well-known scientific revolutions in fundamental physics (the discovery of inertia, of special relativity and of general relativity), I claim that problems that were supposed to be crying for a dynamical explanation in the old paradigm ended up receiving a structural explanation in the new one. This claim is meant to give more substance to Kuhn’s view that revolutions are accompanied by a shift in what needs to be explained, while suggesting at the same time the existence of a pattern that is common to all of the discussed case-studies. It remains to be seen whether also quantum mechanics, in particular entanglement, conforms to this pattern.

The main aim of our paper is to show that interpretative issues belonging to classical General Relativity (GR) might be preliminary to a deeper understanding of conceptual problems stemming from on-going attempts at constructing a quantum theory of gravity. Among such interpretative issues, we focus on the meaning of general covariance and the related question of the identity of points, by basing our investigation on the Hamiltonian formulation of GR. In particular, we argue that the adoption of a peculiar gauge-fixing within the canonical reduction of ADM metric gravity may yield a new solution to the debate between substantivalists and relationists, by suggesting a \emph{tertium quid} between these two age-old positions. Such a third position enables us to evaluate the controversial relationship between entity realism and structural realism in a well-defined case study. After having indicated the possible developments of this approach in Quantum Gravity, we discuss the structuralist and holistic features of the class of spacetime models that are used in the above mentioned canonical reduction.

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.

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.

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.

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.

In the first part of this paper, I try to clear the ground from frequent misconceptions about the relationship between fact and value by examining some uses of the adjective “natural” in ethical controversies. Such uses bear evidence to our “natural” tendency to regard nature (considered in a descriptive sense, as the complex of physical and biological regularities) as the source of ethical norms. I then try to account for the origin of this tendency by offering three related explanations, the most important of which regards it as the outcome of an adaptation: if any behaviour that favours our equilibrium with the environment is potentially adaptive, nothing can be more effective for this goal than developing an attitude toward the natural world that regards it as a dispenser of sacred norms that must be invariably respected. By referring to the Aristotelian notion of human flourishing illustrated in the first part of the paper, in the second I discuss some ethical problems raised by mini-chips implantable under in our bodies. I conclude by defending the potential beneficial effects of such new technological instruments.

Temporal becoming is usually considered the essence of the concept of time. But in our century most physicists and philosophers have defended the view that becoming is dependent on the existence of conscious beings and that there is no ontological difference between past and future. I evaluate these related claims both in light of their conceptual implications and by bringing to bear our best spacetime theories. ;Since a mind-independent becoming should be grounded in an ontological, non-epistemic asymmetry between past and future, I discuss the philosophical motivations for various "non-full views" of the future in contrast to the view that the future is as real as the past. I present the disagreement between these views both in terms of what is and in terms of possession of a definite truth value, thereby distinguishing an ontological and a semantic formulation. A formal definition of the "tree model" of reality allows a clear distinction of the often conflated notions of 'determinate', 'determined' and 'stable', and helps to formulate the differences between the "non-full" views and the "full view" of reality. ;To settle the issue concerning these views, I bring into the discussion the special theory of relativity. I show that oft-discussed arguments against the openness of the future presuppose a clarification of the properties of the relation 'being determinate for', in particular symmetry and transitivity. Within STR, objective becoming can be defended at the cost of relativizing what is determinate to spacetime points, of making the relation of determinedness time-asymmetric, and of denying determinateness to spacelike-related events. ;I conclude by urging that mind-independent temporal becoming can find a more hospitable environment in some isotropic cosmological models of general relativity, a claim that has been unreasonably neglected. If the universe does not present causal anomalies, the proper time of a co-moving 'fundamental particle' can be made common to every other world line. The existence of such a cosmic time would make current scientific talk of 'cosmic evolution' and 'the future of the universe' non-metaphorical.

The literature on the compatibility between the time of our experience--characterized by passage or becoming--and time as is represented within spacetime theories has been affected by a persistent failure to get a clear grasp of the notion of becoming, both in its relation to an ontology of events tt"spreadtt" in a four-dimensional manifold, and in relation to temporally asymmetric physical processes.In the first part of my paper I try to remedy this situation by offering what I consider a clear and faithful explication of becoming, valid independently of the particular spacetime setting in which we operate. Along the way, I will show why the metaphysical debate between the so-called tt"presentiststt" and tt"eternaliststt" is completely irrelevant to the question of becoming, as the debate itself is generated by a failure to distinguish between a tensed and a tenseless sense of tt"existencett". After a much needed distinction between absolute and relational becoming, I then show in what sense classical spacetime physics presupposes both types of becoming, for the simple reason that spacetime physics presupposes an ontology of events. As a consequence, not only does it turn out that using physics to try to provide empirical evidence for the existence of becoming amounts to putting the cart before the horses, but also that the order imposed by tt"the arrow of becomingtt" is more fundamental than any other physical arrow of time, despite the fact that becoming cannot be used to explain why entropy grows, or retarded electromagnetic radiation prevails versus advanced radiation.

In this paper I review three different positions on the wave function, namely: nomological realism, dispositionalism, and configuration space realism by regarding as essential their capacity to account for the world of our experience. I conclude that the first two positions are committed to regard the wave function as an abstract entity. The third position will be shown to be a merely speculative attempt to derive a primitive ontology from a reified mathematical space. Without entering any discussion about nominalism, I conclude that an elimination of abstract entities from one’s ontology commits one to instrumentalism about the wave function, a position that therefore is not as unmotivated as it has seemed to be to many philosophers.

In recent times, there have been notable attempts to introduce an objective present in Minkowski spacetime, a structure that, however, should also be capable to explain some aspects of our experience of time. I claim that the “interactive present” introduced by Arthur and Savitt for such purposes is inadequate, since it turns out to be neither a physically relevant property nor a good explanans of our temporal experience. In its conclusive part, and after having proposed a more adequate model for the time of our experience, I draw some general morals about the relationship between physical time and experiential time.

In this paper I examine the role of dispositional properties in the most frequently discussed interpretations of non-relativistic quantum mechanics. After offering some motivation for this project, I briefly characterize the distinction between non-dispositional and dispositional properties in the context of quantum mechanics by suggesting a necessary condition for dispositionality – namely contextuality – and, consequently, a sufficient condition for non-dispositionality, namely non-contextuality. Having made sure that the distinction is conceptually sound, I then analyze the plausibility of the widespread, monistic ontological thesis about the reducibility of dispositional properties to categorical properties in the context of the philosophy of quantum mechanics. I conclude that with the exception of Bohmian mechanics, the other “minimally realist” views of quantum mechanics require essential dispositions, i.e., dispositions of a non-reducible kind. Interestingly, seen behind the lenses of dispositionalism, Bohr’s and Bohm’s interpretations of quantum mechanics are much closer than it is usually recognized, a fact that could teach us something about the way the quantum world is.

In this paper we argue that the different positions taken by Dyson and Feynman on Feynman diagrams’ representational role depend on different styles of scientific thinking. We begin by criticizing the idea that Feynman Diagrams can be considered to be pictures or depictions of actual physical processes. We then show that the best interpretation of the role they play in quantum field theory and quantum electrodynamics is captured by Hughes' Denotation, Deduction and Interpretation theory of models (DDI), where “models” are to be interpreted as inferential, non-representational devices constructed in given social contexts by the community of physicists.

After some suggestions about how to clarify the confused metaphysical distinctions between dispositional and non-dispositional or categorical properties, I review some of the main interpretations of QM in order to show that – with the relevant exception of Bohm’s minimalist interpretation – quantum ontology is irreducibly dispositional. Such an irreducible character of dispositions must be explained differently in different interpretations, but the reducibility of the contextual properties in the case of Bohmian mechanics is guaranteed by the fact that the positions of particles play the role of the categorical basis, a role that in other interpretations cannot be filled by anything else. In Bohr’s and Everett-type interpretations, dispositionalism is instrumentalism in disguise.

Since the onset of logical positivism, the general wisdom of the philosophy of science has it that the kantian philosophy of (space and) time has been superseded by the theory of relativity, in the same sense in which the latter has replaced Newton’s theory of absolute space and time. On the wake of Cassirer and Gödel, in this paper I raise doubts on this commonplace by suggesting some conditions that are necessary to defend the ideality of time in the sense of Kant. In the last part of the paper I bring to bear some contemporary physical theories on such conditions.