Primitive ontology and quantum state in the GRW matter density theory

The paper explains in what sense the GRW matter density theory (GRWm) is a primitive ontology theory of quantum mechanics and why, thus conceived, the standard objections against the GRW formalism do not apply to GRWm. We consider the different options for conceiving the quantum state in GRWm and argue that dispositionalism is the most attractive one.Comment: arXiv admin note: text overlap with arXiv:quant-ph/0603027 by other author

Causal Warrant for Realism about Particle Physics

While scientific realism generally assumes that successful scientific explanations yield information about reality, realists also have to admit that not all information acquired in this way is equally well warranted. Some versions of scientific realism do this by saying that explanatory posits with which we have established some kind of causal contact are better warranted than those that merely appear in theoretical hypotheses. I first explicate this distinction by considering some general criteria that permit us to distinguish causal warrant from theoretical warrant. I then apply these criteria to a specific case from particle physics, claiming that scientific realism has to incorporate the distinction between causal and theoretical warrant if it is to be an adequate stance in the philosophy of particle physic

What Is Kitcher's Real Realist Really a Realist about?

I review Philip Kitcher's defence of scientific realism against the so-called pessimistic induction. While supporting his overall strategy, I claim that there is a lacuna in Kitcher's argument, which needs to be filled by spelling out more precisely what parts of scientific theories we should be realists about. I attempt to do this and to show that scientific realism can thereby not only be protected against the pessimistic induction but also against a recent argument by Kyle Stanford, known as the "new induction

Dissolving the Measurement Problem Is Not an Option for the Realist

This paper critically assesses the proposal that scientific realists do not need to search for a solution of the measurement problem in quantum mechanics, but should instead dismiss the problem as ill-posed. James Ladyman and Don Ross have sought to support this proposal with arguments drawn from their naturalized metaphysics and from a Bohr-inspired approach to quantum mechanics. I show that the first class of arguments is unsuccessful, because formulating the measurement problem does not depend on the metaphysical commitments which are undermined by ontic structural realism, rainforest realism, or naturalism in general. The second class of arguments is problematic due to its refusal to provide an analysis of the term "measurement". It turns out that the proposed dissolution of the measurement problem is in conflict not only with traditional forms of scientific realism but even with the rather minimal realism that Ladyman and Ross themselves defend. The paper concludes with a brief discussion of two related proposals: Healey's pragmatist approach and Bub's information-theoretic interpretation

Dissolving the Measurement Problem Is Not an Option for the Realist

This paper critically assesses the proposal that scientific realists do not need to search for a solution of the measurement problem in quantum mechanics, but should instead dismiss the problem as ill-posed. James Ladyman and Don Ross have sought to support this proposal with arguments drawn from their naturalized metaphysics and from a Bohr-inspired approach to quantum mechanics. I show that the first class of arguments is unsuccessful, because formulating the measurement problem does not depend on the metaphysical commitments which are undermined by ontic structural realism, rainforest realism, or naturalism in general. The second class of arguments is problematic due to its refusal to provide an analysis of the term "measurement". It turns out that the proposed dissolution of the measurement problem is in conflict not only with traditional forms of scientific realism but even with the rather minimal realism that Ladyman and Ross themselves defend

The Foundational Significance of Leggett's Non-local Hidden-Variable Theories

Laudisa (Found. Phys. 38:1110-1132, 2008) claims that experimental research on the class of non-local hidden-variable theories introduced by Leggett is misguided, because these theories are irrelevant for the foundations of quantum mechanics. I show that Laudisa's arguments fail to establish the pessimistic conclusion he draws from them. In particular, it is not the case that Leggett-inspired research is based on a mistaken understanding of Bell's theorem, nor that previous no-hidden-variable theorems already exclude Leggett's models. Finally, I argue that the framework of Bohmian mechanics brings out the importance of Leggett tests, rather than proving their irrelevance, as Laudisa suppose

Textbook Quantum Mechanics and the Problem of Ontological Commitment

One important difference between quantum mechanics (QM) and most other scientific theories is that we cannot just look at QM textbooks in order to find out what the theory is about (beyond mere predictions of possible measurement outcomes). If questions about what is represented by the quantum formalism are addressed at all, the answers given by textbooks do not amount to a coherent ontology of QM. Proposals for such ontologies exist, but each of them has its own peculiar way of going beyond textbook QM, by either adding variables (e. g., the de Broglie-Bohm theory), modifying the dynamics (e. g., the GRW model) or reinterpreting our experience of unique measurement outcomes (e. g. Everettian QM). The fact that we are (currently, and to some extent in principle) unable to experimentally discriminate between these proposals creates a dilemma for anyone who expects QM to inform us about the structure of reality. One can either opt for one particular version of QM (as, e. g., Wallace (2012) does for the Everettian approach or Esfeld and Deckert (2017) for the Bohmian), but then one faces a problem of underdetermination that is usually considered problematic for a realist’s commitment; or one can limit one’s ontological commitment to some core content of QM unaffected by the underdetermination between its different versions, but this seems to sacrifice realism with respect to large parts of QM (as exemplified most explicitly in Hoefer forthcoming). In my talk, I will sketch a way out of this dilemma, by showing that the core of QM, as it is formulated in standard textbooks, allows for a much more substantive ontological commitment than is usually acknowledged. For this purpose, I will first defend the ontological respectability of textbook QM against a recent attack by Callender (forthcoming) and then substantiate my claim by looking at an example that has been claimed to be particularly troubling for an ontologically committed realism about QM, namely the case of spin (see Saatsi forthcoming). The features of the kind of realism I propose will highlight the way in which QM forces us to change our thinking about the ontological content of scientific theories. References: Callender, C. (forthcoming): „Can we quarantine the quantum blight?“ In French and Saatsi (forthcoming). Esfeld, M. and D.-A. Deckert (2017): A Minimalist Ontology of the Natural World. Routledge. French, S. and Saatsi, J. (Eds.) (fortchcoming): Scientific Realism and the Quantum. Oxford University Press. Hoefer, C. (forthcoming): „Scientific realism without the quantum“. In French and Saatsi (forthcoming). Saatsi, J. (forthcoming): „Truth vs. progress realism about spin“. In French and Saatsi (forthcoming). Walace, D. (2012): The Emergent Multiverse: Quantum Theory according to the Everett Interpretation. Oxford University Press

Quantum Ontology without Speculation

Existing proposals concerning the ontology of quantum mechanics (QM) either involve speculation that goes beyond the scientific evidence or abandon realism about large parts of QM. This paper proposes a way out of this dilemma, by showing that QM as it is formulated in standard textbooks allows for a much more substantive ontological commitment than is usually acknowledged. For this purpose, I defend a non-fundamentalist approach to ontology, which is then applied to various aspects of QM. In particular, I will defend realism about spin, which has been viewed as a particularly hard case for the ontology of QM

Dissolving the Measurement Problem Is Not an Option for the Realist

This paper critically assesses the proposal that scientific realists do not need to search for a solution of the measurement problem in quantum mechanics, but should instead dismiss the problem as ill-posed. James Ladyman and Don Ross have sought to support this proposal with arguments drawn from their naturalized metaphysics and from a Bohr-inspired approach to quantum mechanics. I show that the first class of arguments is unsuccessful, because formulating the measurement problem does not depend on the metaphysical commitments which are undermined by ontic structural realism, rainforest realism, or naturalism in general. The second class of arguments is problematic due to its refusal to provide an analysis of the term "measurement". It turns out that the proposed dissolution of the measurement problem is in conflict not only with traditional forms of scientific realism but even with the rather minimal realism that Ladyman and Ross themselves defend. The paper concludes with a brief discussion of two related proposals: Healey's pragmatist approach and Bub's information-theoretic interpretation

Dissolving the Measurement Problem Is Not an Option for the Realist

This paper critically assesses the proposal that scientific realists do not need to search for a solution of the measurement problem in quantum mechanics, but should instead dismiss the problem as ill-posed. James Ladyman and Don Ross have sought to support this proposal with arguments drawn from their naturalized metaphysics and from a Bohr-inspired approach to quantum mechanics. I show that the first class of arguments is unsuccessful, because formulating the measurement problem does not depend on the metaphysical commitments which are undermined by ontic structural realism, rainforest realism, or naturalism in general. The second class of arguments is problematic due to its refusal to provide an analysis of the term "measurement". It turns out that the proposed dissolution of the measurement problem is in conflict not only with traditional forms of scientific realism but even with the rather minimal realism that Ladyman and Ross themselves defend