My main concern has always been to understand how we can use our best physical theories to answer general metaphysical and epistemological questions, and my research focuses fundamentally on that. I have worked in the foundations of quantum mechanics with the aim of understanding what our metaphysical commitments and the epistemological limitations are if we live in a quantum world. I endorse a view based on the notion of “primitive ontology,” according to which all fundamental physical theories have a similar structure. Roughly, the idea is that satisfactory fundamental physical theories have two components: on the one hand there is matter, described in terms of a three-dimensional object is space (or four-dimensional object in space-time); and on the other hand, we have the laws of nature, which can be more abstractly defined, whose role is to fundamentally describe how matter behaves. In this way, the view is both descriptive and normative: it prescribes how, in order to be explanatory, a fundamental physical theory should be structured, and it describes how many theories that in the past we have found satisfactory shared a similar structure.
According to this approach, therefore, all quantum theories have a common structure. This thesis has been explored in many papers. “E’ completa la descrizione della realtà fisica fornita dalla meccanica quantistica?”, “La storia del gatto che era sia vivo che morto,” and “Ontologie quantistiche di particelle, campi e lampi” emphasize respectively how the early quantum interpretations required some fixing, how it was done, and what the consequences of such fixing are for our picture of reality. “On the Common Structure of Bohmian Mechanics and the Ghirardi-Rimini-Weber Theory” and “Many-Worlds and Schrödinger’s First Quantum Theory” are the articles in which we spell out the thesis of the common structure between the three most popular quantum interpretations, namely Bohmian mechanics, GRW, and Many-Worlds. In “On the Metaphysics of Quantum Mechanics” I generalize the argument to all the quantum interpretations, and in “Primitive Ontology and the Structure of Fundamental Physical Theories,” I discuss the basic ingredient of the above mentioned common structure, and extent the view to all fundamental physical theories, including classical and relativistic mechanics. In “Predictions and Primitive Ontology in Quantum Foundations: A Study of Examples,” it is analyzed how empirical predictions are derived from the theoretical framework, and how they ultimately depend on the choice of the ontology of the theory. In “Primitive Ontology in a Nutshell” I reply to some concerns and questions that are commonly raised about the primitive ontology view.
The primitive ontology approach, in addition of being a unification view of the different quantum interpretations, has several other advantages over the received view. In particular, it insightfully provides an account of theory formation, and it unifies the classical and quantum understandings of world. In “On the Classical Limit of Quantum Mechanics” and “Seven Steps toward the Classical World,” I developed the proposal that one can establish that material quantum objects behave classically just in case there is a “local plane wave” regime, which naturally corresponds to the suppression of all quantum interference. In the forthcoming article “Primitive Ontology and the Classical World,” I argue that one can meaningfully talk about the classical limit only in the context of the primitive ontology approach. The continuity between our quantum and classical understanding of the world is discussed in “Quantum Mechanics and Paradigm Shifts,” in which I argue that it is unnecessary to treat the quantum revolution as a Kuhnian revolution, given that there is no irreducible classical-quantum distinction. I have also published an article “Primitive Ontology and Scientific Realism. Or: The Pessimistic Meta-Induction and the Nature of the Wave Function,” in which I use the primitive ontology approach to connect the debate over the nature of the wave function in philosophy of physics with the traditional debate about realism and antirealism in philosophy of science. I argue that within the primitive ontology approach one can defeat the pessimistic meta-induction argument against scientific realism more successfully than the alternative wave function realism or ontic structuralism (moderate or radical). I further analyze the nature of the wave function in “A New Argument for the Nomological Interpretation of the Wave Function: The Galilean Group and the Classical Limit of Nonrelativistic Quantum Mechanics.” The point of the paper is to argue that the best way preserve symmetry properties of nonrelativistic quantum mechanics is to interpret the wave function as a nomological entity. In fact, Galilean symmetry suggests the wave function being a ray in Hilbert space, which in turns suggests it being analog to a gauge potential, which is traditionally is being considered as part of the law, and not part of the ontology of matter.
In a forthcoming paper, “Towards a Structuralist Elimination of Properties: Scientific Realism, Quantum Ontology and the Nature of Reality,” I take the view to the next step, arguing that one should consider mass, charge and spin like part of the laws of nature and not as fundamental properties of matter. In the paper I stress how this approach could be interesting for those ontic structuralists working on eliminating properties from the ontology of fundamental physical theories.
Moreover, the primitive ontology view, in part because it emphasizes the role of symmetries, has allowed me to gain a peculiar perspective also on other theories. For instance, in “Maxwell’s Paradox: The Metaphysics of Classical Electrodynamics and its Time Reversal Invariance,” I argue that classical electrodynamics has a paradoxical flavor: the claim that there are electromagnetic fields in the world and the claim that the theory possesses the symmetry properties that we take to have are incompatible. This is connected with the primitive ontology idea: the main characteristics of a theory, like symmetry properties for instance, will crucially depend on which primitive ontology is selected for it.
In “Space, Time, and (how they) Matter: a Discussion about some Metaphysical Insights Provided by our Best Fundamental Physical Theories,” I use this perspective in the debates on the philosophy of time, shedding light on some recent claims that space and time can be dispensed with.
In “What is Bohmian Mechanics,” many confusions and misperceptions about the nature of such theory are clarified, underlining its virtues of coherence, simplicity, clarity and understandability, and its insightfulness in analyzing foundational issues, as well as certain experimental setups.
I have written several book reviews, the last of which is the volume “Protective Measurement and Quantum Reality” edited by Shan Gao. Also, my review of Hemmo and Schenker’s “The Road to Maxwell’s Demon,” created some debate and the authors decided it was worth discussing. I have my reply to them published as well in “Reply to Authors: ‘The Road to Maxwell’s Demon’.”
I am also co-author of a book on the philosophy and foundations of physics, written in Italian, together with Mauro Dorato (Department of Philosophy, University of Rome III, Italy), Federico Laudisa (Department of Philosophy, University of Milano-Bicocca, Italy) and Nino Zanghì. The book, “La Natura delle Cose” (“The Nature of Things”), has been written for a philosophy or a physics student who is interested in the main problems of the theory of relativity, statistical mechanics, quantum theory and causation, but it might be accessible, even if with some effort, by an interested reader. My contribution is constructed along the lines of the dissertation, and argues for the common structure of fundamental physical theories, focusing on quantum theories.