Realism comes in many varieties, in science and elsewhere. Van Fraassen's influential formulation took scientific realism to include the view that science aims to give us, in its theories, a literally true story of what the world is like. So understood, a quantum realist takes quantum theory to aim at correctly representing the world: many would add that its success justifies believing this representation is more or less correct. But quantum realism has been understood (...) both more narrowly and more broadly. A pragmatist considers use prior to representation and this has prompted some to dub pragmatist views anti-realist, including the view of quantum theory I have been developing recently. But whether a pragmatist view of quantum theory should be labeled anti-realist depends not only on its ingredients but also on how that label should be applied. Pragmatism offers a healthy diet of quantum realism. (shrink)

The work of Gleason and of Kochen and Specker has been thought to refute a naïve realist approach to quantum mechanics. The argument of this paper substantially bears out this conclusion. The assumptions required by their work are not arbitrary, but have sound theoretical justification. Moreover, if they are false, there seems no reason why their falsity should not be demonstrable in some sufficiently ingenious experiment. Suitably interpreted, the work of Bell and Wigner may be seen to yield independent (...) arguments for the falsity of naïve realistic approach to quantum mechanics. Quantum mechanics is no more like classical statistical mechanics than its creators thought it was. (shrink)

1. Realism. Physicists claim rightly to speak about reality. But what does “reality” mean?2. The Copenhagen Interpretation (CI). We consider CI as a minimal semantics for quantum theory, leaving ways open for additional interpretation.3. The Measuring Process. Several interpretations of the process as given in the liteature are discussed.4. Realistic Interpretation. Discussion of the de Broglie-Bohm-Bell interpretation. If well formulated, it is not a necessary consequence of quantum theory but cannot be excluded.

The theories of pre-quantum physics are standardly seen as representing physical systems and their properties. Quantum mechanics in its standard form is a more problematic case: here, interpretational problems have led to doubts about the tenability of realist views. Thus, QBists and Quantum Pragmatists maintain that quantum mechanics should not be thought of as representing physical systems, but rather as an agent-centered tool for updating beliefs about such systems. It is part and parcel of such views (...) that different agents may have different beliefs and may assign different quantum states. What results is a collection of agent-centered perspectives rather than a unique representation of the physical world. In this paper we argue that the problems identified by QBism and Quantum Pragmatism do not necessitate abandoning the ideal of representing the physical world. We can avail ourselves of the same puzzle-solving strategies as employed by QBists and pragmatists by adopting a perspectival quantum realism. According to this perspectivalism objects may possess different, but equally objective properties with respect to different physically defined perspectives. We discuss two options for such a perspectivalism, a local and a nonlocal one, and apply them to Wigner’s friend and EPR scenarios. Finally, we connect quantum perspectivalism to the recently proposed philosophical position of fragmentalism. (shrink)

Non-relativistic quantum mechanics is incompatible with our everyday or ‘classical’ intuitions about realism, not only at the microscopic level but also at the macroscopic level. The latter point is highlighted by the ‘cat paradox’ presented by Schrödinger. Since our observations are always made at the macroscopic level — even when applying the formalism to the microscopic level — the failure of classical realism at the macroscopic level is actually more fundamental and crucial.

A critique of phenomenological interpretation of quantum Bayesianism (QBism) is offered, in particular, the position of M. Bitbol and L. de La Tremblay, which removes remnants of scientific realism from QBism and adopts a radically phenomenological first person point of view. It is shown that phenomenological view of quantum mechanics cannot explain cognition of quantum reality and behavior of real quantum systems, because the ultimate reality for phenomenology is autonomous phenomena, which, in fact, do not (...) exist. Our proposed contextual quantum realism (CQR) does not invert, as the mentioned authors do, but rejects, the traditional relation between experience and reality. By reinterpreting QBism, our CQR removes remnants of phenomenology from it, but in such a way as not to fall into the other extreme – metaphysical realism. (shrink)

According to Healey’s pragmatist quantum realism, the only physical properties of quantum systems are those to which the Born rule assigns probabilities. In this paper, I argue that this approach to quantum theory fails to explain the results of protective measurements.

ABSTRACT Topos quantum theory is standardly portrayed as a kind of ‘neo-realist’ reformulation of quantum mechanics.1 1 In this article, I study the extent to which TQT can really be characterized as a realist formulation of the theory, and examine the question of whether the kind of realism that is provided by TQT satisfies the philosophical motivations that are usually associated with the search for a realist reformulation of quantum theory. Specifically, I show that the notion (...) of the quantum state is problematic for those who view TQT as a realist reformulation of quantum theory. 1Introduction 2Topos Quantum Theory 2.1Phase space 2.2Hilbert space 2.3Beyond Hilbert space 2.4Defining realism 2.5The spectral presheaf 2.6The logic of topos quantum theory 3Interpreting States in Topos Quantum Theory 4Interpreting Truth Values and Clopen Subobjects in Topos Quantum Theory 4.1Interpreting the truth values 4.2Interpreting Subcl 5Neo-realism 5.1The covariant approach 6Conclusion. (shrink)

A Review: Jens Hebor. The Standard Conception as Genuine Quantum Realism.

Quantum mechanics has sometimes been taken to be an empiricist (vs. realist) theory. I state the empiricist's argument, then outline a recently noticed type of measurement--protective measurement--that affords a good reply for the realist. This paper is a reply to scientific empiricism (about quantum mechanics), but is neither a refutation of that position, nor an argument in favor of scientific realism. Rather, my aim is to place realism and empiricism on an even score in regards to (...) quantum theory. (shrink)

This book is a critical introduction to the long-standing debate concerning the conceptual foundations of quantum mechanics and the problems it has posed for physicists and philosophers from Einstein to the present. Quantum theory has been a major infulence on postmodernism, and presents significant problems for realists. Keeping his own realist position in check, Christopher Norris subjects a wide range of key opponents and supporters of realism to a high and equal level of scrutiny. With a characteristic (...) combination of rigour and intellectual generosity, he draws out the merits and weaknesses from opposing arguments. In a sequence of closely argued chapters, Norris examines the premises of orthodox quantum theory, as developed most influentially by Bohr and Heisenberg, and its impact on varous philosophical developments. These include the ideas developed by W.V Quine, Thomas Kuhn, Michael Dummett, Bas van Fraassen, and Hilary Puttnam. In each case, Norris argues, these thinkers have been influenced by the orthodox construal of quantum mechanics as requiring drastic revision of principles which had hitherto defined the very nature of scientific method, causal explanati and rational enquiry. Putting the case for a realist approach which adheres to well-tried scientific principles of causal reasoning and inference to the best explanation, Christopher Norris clarifies these debates to a non-specialist readership and scholars of philosophy, science studies and the philosophy of science alike. Quantum Theory and the Flight From Realism suggests that philosophical reflection can contribute to a better understanding of these crucial, current issues. (shrink)

I examine the epistemological debate on scientific realism in the context of quantum physics, focusing on the empirical underdetermin- ation of different formulations and interpretations of QM. I will argue that much of the interpretational, metaphysical work on QM tran- scends the kinds of realist commitments that are well-motivated in the light of the history of science. I sketch a way of demarcating empirically well-confirmed aspects of QM from speculative quantum metaphysics in a way that coheres with (...) anti-realist evidence from the history of science. The minimal realist attitude sketched withholds realist com- mitment to what quantum state |Ψ⟩ represents. I argue that such commitment is not required for fulfilling the ultimate realist motiva- tion: accounting for the empirical success of quantum mechanics in a way that is in tune with a broader understanding of how theoretical science progresses and latches onto reality. (shrink)

This edited collection provides new perspectives on some metaphysical questions arising in quantum mechanics. These questions have been long-standing and are of continued interest to researchers and graduate students working in physics, philosophy of physics and metaphysics. It features contributions from a diverse set of researchers, ranging from senior scholars to junior academics, working in varied fields, from physics to philosophy of physics and metaphysics. The contributors reflect on issues about fundamentality (is quantum theory fundamental? If so, what (...) is its fundamental ontology?), ontological dependence (how do ordinary objects exist even if they are not fundamental?), realism (what kind of realism is compatible with quantum theory?), indeterminacy (can the world itself exhibit ontological indeterminacy?). With contributions from both physicists (including Nobel Prize winner Gerard 't Hooft), science communicators and philosophers. (shrink)

This paper examines the epistemological significance of the present situation of underdetermination in quantum mechanics. After analyzing this underdetermination at three levels---formal, ontological, and methodological---the paper considers implications for a number of variants of the thesis of scientific realism in fundamental physics and reassesses Lakatos‘ characterization of progress in physical theory in light of the present situation. Next, this paper considers the implications of underdetermination for Weinberg’s ‘‘dream of a final theory.’’ Finally, the paper concludes by suggesting how (...) one might still think of realism and progress in fundamental physics despite the possibility of persistent underdetermination in quantum mechanics. (shrink)

Scientific realism does not view theoretical terms as mere instruments of experimental predictions; it grants referential status to natural kind terms with 'epistemic access' and view scientific theories and terms as corresponding to physical phenomena and entities which exist independently of observation, and as thereby being the source of objective -approximate and not absolute- knowledge of the physical realm. As a result, scientific realism is accused of ontologising the unobservables. Against this charge, scientific realism posits the idea (...) of the dialectical relation between theoretical terms referring to the unobservables and scientific methods. The second argument made by realism is the ‘no miracle’ thesis. These arguments stand challenged by the Copenhagen interpretation of quantum mechanics. The aim of the paper is to examine the relevance of the two arguments of scientific realism in countering the idea that the existence of quantum states in the microphysical world renders realism obsolete. (shrink)

A comprehensive formal system is developed that amalgamates the operational and the realistic approaches to quantum mechanics. In this formalism, for example, a sharp distinction is made between events, operational propositions, and the properties of physical systems.

The roles of classical realism, logical positivism, and pragmatic instrumentalism in the shaping of fundamental ideas in quantum physics are examined in the light of some recent historical and sociological studies of the factors that influenced their development. It is shown that those studies indicate that the conventionalistic form of instrumentalism that has dominated all the major post-World War II developments in quantum physics is not an outgrowth of the Copenhagen school, and that despite the “schism” in (...) twentieth century physics created by the Bohr-Einstein “disagreements” on foundational issues in quantum theory, both their philosophical stands were very much opposed to those of conventionalistic instrumentalism. Quotations from the writings of Dirac, Heisenberg, Popper, Russell, and other influential thinkers, are provided, illustrating the fact that, despite the various divergencies in their opinions, they all either opposed the instrumentalist concept of “truth” in general, or its conventionalistic version in post-World War II quantum physics in particular. The basic epistemic ideas of a quantum geometry approach to quantum physics are reviewed and discussed from the point of view of a quantum realism that seeks to reconcile Bohr's “positivism” with Einstein's “realism” by emphasizing the existence of an underlying quantum reality, in which they both believed. This quantum geometry framework seeks to introduce geometro-stochastic concepts that are specifically designed for the systematic description of that underlying quantum reality, by developing the conceptual and mathematical tools that are most appropriate for such a use. (shrink)

The interpretation of quantum mechanics has been a problem since its founding days. A large contribution to the discussion of possible interpretations of quantum mechanics is given by the so-called impossibility proofs for hidden variable models; models that allow a realist interpretation. In this thesis some of these proofs are discussed, like von Neumann’s Theorem, the Kochen-Specker Theorem and the Bell-inequalities. Some more recent developments are also investigated, like Meyer’s nullification of the Kochen-Specker Theorem, the MKC-models and Conway (...) and Kochen’s Free Will Theorem. This last one is taken to suggest that the problems that arise for certain interpretations of quantum mechanics are not limited to realist interpretations only, but also affect certain instrumentalist interpretations. It is argued that one may arrive at a more satisfying interpretation of quantum mechanics if one adopts a logic that seems more compatible with the instrumentalist viewpoint namely, intuitionistic logic. The motivations for adopting this form of logic rather than classical logic or quantum logic are linked to some of the philosophical ideas of Bohr. In particular a new interpretation of Bohr’s notion of complementarity is proposed. Finally some possibilities are explored for linking the intuitionistic interpretation of quantum mechanics to the mathematical formalism of the theory. (shrink)

Scientific realism is the view that our best scientific theories can be regarded as (approximately) true. This is connected with the view that science, physics in particular, and metaphysics could (and should) inform one another: on the one hand, science tells us what the world is like, and on the other hand, metaphysical principles allow us to select between the various possible theories which are underdetermined by the data. Nonetheless, quantum mechanics has always been regarded as, at best, (...) puzzling, if not contradictory. As such, it has been considered for a long time at odds with scientific realism, and thus a naturalized quantum metaphysics was deemed impossible. Luckily, now we have many quantum theories compatible with a realist interpretation. However, scientific realists assumed that the wave-function, regarded as the principal ingredient of quantum theories, had to represent a physical entity, and because of this they struggled with quantum superpositions. In this paper I discuss a particular approach which makes quantum mechanics compatible with scientific realism without doing that. In this approach, the wave-function does not represent matter which is instead represented by some spatio-temporal entity dubbed the primitive ontology: point-particles, continuous matter fields, space-time events. I argue how within this framework one develops a distinctive theory-construction schema, which allows to perform a more informed theory evaluation by analyzing the various ingredients of the approach and their inter-relations. (shrink)

Foundations of Relational Realism: A Topological Approach to Quantum Mechanics and the Philosophy of Nature by Michael Epperson and Elias Zafiris sets out to achieve three goals: to develop a version of Whiteheadian metaphysics that the authors call “relational realism”; to formalize relational realism in terms of category theory, in particular sheaf theory; and to use relational realism to solve the interpretative problems of quantum mechanics. These goals are ambitious, to say the least, and (...) all this is leaving aside those sections of FRR which argue that relational realism yields the key to understanding quantum gravity!The text is 388 pages long and comprises two parts. Part I, by Epperson, introduces relational realism and its application to quantum mechanics. Part II, by Zafiris, develops the sheaf theory formalism for relational realism. As the authors say, their exposition is “nonlinear”, and this feature of FRR, alon .. (shrink)

What ontology does realism about the quantum state suggest? The main extant view in contemporary philosophy of physics is wave-function realism . We elaborate the sense in which wave-function realism does provide an ontological picture, and defend it from certain objections that have been raised against it. However, there are good reasons to be dissatisfied with wave-function realism, as we go on to elaborate. This motivates the development of an opposing picture: what we call spacetime (...) state realism , a view which takes the states associated to spacetime regions as fundamental. This approach enjoys a number of beneficial features, although, unlike wave-function realism, it involves non-separability at the level of fundamental ontology. We investigate the pros and cons of this non-separability, arguing that it is a quite acceptable feature, even one which proves fruitful in the context of relativistic covariance. A companion paper discusses the prospects for combining a spacetime-based ontology with separability, along lines suggested by Deutsch and Hayden. (shrink)

The belief that quantum mechanics does not admit a realistic interpretation is widespread. According to some scholars concerned with the foundations of QM all existing interpretations of this theory presuppose instead a form of realism which consists in assuming that QM deals with individual objects and their properties. We uphold in the present paper that the arguments supporting the contextuality and the nonlocality of QM are a significant clue to the implicit adoption of stronger forms of realism. (...) If these kinds of realism are substituted by a simpler and more intuitive semantic realism one can contrive a noncontextual and local interpretation of the formalism of QM. Moreover one can provide a model for such an interpretation in which local realism and QM do not conflict and some fundamental problems of the standard interpretation of QM are avoided. (shrink)

Based on the new general framework for the probabilistic description of experiments, introduced in [E.R. Loubenets, Research Report No 8, MaPhySto, University of Aarhus, Denmark (2003); Proceedings Conference “Quantum Theory, Reconsideration of Foundations”, Ser. Math. Modeling, Vol. 10 (University Press, Vaxjo, 2004), pp. 365–385], we analyze in mathematical terms the link between the validity of Bell-type inequalities under joint experiments upon a system of any type and the physical concept of “local realism”. We prove that the violation of (...) Bell-type inequalities in the quantum case has no connection with the violation of “local realism”. In a general setting, we formulate in mathematical terms the condition on “local realism” under a joint experiment and consider examples of quantum “locally realistic” joint experiments. We, in particular, show that quantum joint experiments of the Alice/Bob type are “locally realistic”. For an arbitrary bipartite quantum state, we derive quantum analogs of the original Bell inequality. In view of our results, we argue that the violation of Bell-type inequalities in the quantum case cannot be a valid argument in the discussion on locality or non-locality of quantum interactions. (shrink)

One of the most influential contemporary authors of the new materialist turn in the social sciences is Karen Barad. Barad’s work in agential realism, based on her interpretations of quantum physics, has been widely cited within a growing body of new materialist publications. However, in translating Barad’s assertions into social domains, there has been increasing critical appraisal of the physics underlying her work and its relationship with non-quantum domains. In this paper, we contribute to this discussion by (...) exploring aspects of agential realism through quantum decoherence and quantum Darwinism. We explore implications for Barad’s metaphysics and the relationship of the social with the rest of the material world. (shrink)

Scientific realism is discussed in a variety of quantum mechanical settings, and defended against rival views on a number of scores. The search for the hidden is the source of much scientific creativity.

We first present a realistic framework for quantum probability theory based on the path integral formalism of quantum mechanics and illustrate this framework by constructing a model that describes a quantum particle evolving in a discrete space-time lattice. We then present a finite model for describing the internal dynamics of “elementary particles” and show that this model gives the standard particle classification scheme and successfully predicts particle masses.

ABSTRACT: The article examines the controversial relation of scientific realism with quantum mechanics. To this end, two distinct discussions are invoked: the discussion about ‘realism’ in the context of quantum mechanics and the discussion about ‘scientific realism’ in the context of the general philosophy of science. The aim is to distinguish them in order, first, to argue that the former—revolving around ‘local realism’ and the theorems of Bell and Kochen–Specker—unjustifiably identifies realism with features (...) of a particular worldview, and thereby fosters the impression that the failure of ‘local realism’ in quantum experiments constitutes a failure of scientific realism too; and, second, in light of the latter discussion, to claim that scientific realism and quantum mechanics can be compatible—there is ground for dealing with quantum measurement simply as a physical mind-independent interaction. Therefore, a realist approach to the theory is possible despite its notorious measurement problem, even if th... (shrink)

D. Dieks has proposed a semantical rule which he claims yields a realistic interpretation of the formalism of quantum mechanics without the projection postulate. I argue that his proposal is unacceptable because it violates a natural requirement of psychophysical parallelism. His "semantical rule" is not an acceptable interpretive rule because it does not identify structures in the theory with structures in our experience, but postulates a merely probabilistic relationship between the two. Dieks' interpretation is contrasted with Everett's relative state (...) interpretation, which attempts the same task but respects psychophysical parallelism. (shrink)

In The Philosophy of Information, Luciano Floridi presents an ontological theory of Being qua Being, which he calls “Informational Structural Realism”, a theory which applies, he says, to every possible world. He identifies primordial information (“dedomena”) as the foundation of any structure in any possible world. The present essay examines Floridi’s defense of that theory, as well as his refutation of “Digital Ontology” (which some people might confuse with his own). Then, using Floridi’s ontology as a starting point, the (...) present essay adds quantum features to dedomena, yielding an ontological theory for our own universe, Quantum Informational Structural Realism, which provides a metaphysical interpretation of key quantum phenomena, and diminishes the “weirdness” or “spookiness” of quantum mechanics. (shrink)

We expound an alternative to the Copenhagen interpretation of the formalism of nonrelativistic quantum mechanics. The basic difference is that the new interpretation is formulated in the language of epistemological realism. It involves a change in some basic physical concepts. The ψ function is no longer interpreted as a probability amplitude of the observed behaviour of elementary particles but as an objective physical field representing the particles themselves. The particles are thus extended objects whose extension varies in time (...) according to the variation of ψ. They are considered as fundamental regions of space with some kind of nonlocality. Special consideration is given to the Heisenberg relations, the Einstein-Podolsky- Rosen correlations, the reduction process, the problem of measurement, and the quantum-statistical distributions. (shrink)

After a brief account of theway quantum theory deals with naturalprocesses, the crucial problem that such atheory meets, the measurement or, better, themacro-objectification problem is discussed.The embarrassing aspects of the occurrence ofentangled states involving macroscopic systemsare analyzed in details. The famous example ofSchroedinger's cat is presented and it ispointed out how the combined interplay of thesuperposition principle and the ensuingentanglement raises some serious difficultiesin working out a satisfactory quantum worldview, agreeing with our definiteperceptions. The orthodox solution to themacro-objectification (...) problem, i.e. thepostulate of wave packet reduction, isanalyzed and is proved to be inconsistent withthe assumption that the theory governes alsothe measurement process. After these premises,the rest of the paper is devoted to discuss arecent proposal of overcoming the difficultiesof the standard formalism by acceptingnonlinear and stochastic modifications of thequantum dynamics. The proposed theory is shownto agree with all known predictions of thestandard theory concerning microscopic systemsand to account, on the basis of a universaldynamics which is assumed to govern allnatural processes, for wave packet reductionin measurement processes and, more important,to eliminate all the difficulties concerningmacroscopic situations. Actually, the proposedtheory allows one to take consistently amacrorealistic position about natural processes and about our definite perceptions. (shrink)

Amid the wide variety of interpretations of quantum mechanics, the notion of a fully coherent ontological interpretation has seen a promising evolution over the last few decades. Despite this progress, however, the old dualistic categorical constraints of subjectivity and objectivity, correlate with the metrically restricted definition of local and global, have remained largely in place – a reflection of the broader, persistent inheritance of these comfortable strictures throughout the evolution of modern science. If one traces this inheritance back to (...) its ancient roots in Plato and Aristotle, it is clear that the coherence, scientific utility, and historical durability of the various natural philosophies that followed have been directly proportional to their commitment, tacit or explicit, to object-oriented realism. As Simondon might put it, it is a commitment to the primacy of individuated substance over the process of individuation. For Whitehead, it is the misplaced assimilation of becoming to being, of potentiality to actuality. Quantum mechanics has challenged this commitment with a combined breadth and depth of force that far exceeds any other theory in the history of science. The theory’s objectively demonstrable empirical application is manifest only by way of a fundamentally subjective, context-dependent mechanism of measurement. More compelling still, actual system states are always actualizations of locally contextualized yet globally conditioned potential system states, such that “globally objective” reality is no longer merely the object of local measurement, but also its product. Thus, any coherent, ontological interpretation of quantum theory must include a conceptual framework by which objectivity and subjectivity, actuality and potentiality, global and local, being and becoming, individuated fact and process of individuation, are no longer understood as merely epistemic, mutually exclusive category pairs descriptive of an already extant, closed reality – but rather as mutually implicative ontological categories explicative of an ontogenetic, open reality-in-process. (shrink)

Quantum probability (QP) theory can be seen as a type of vector symbolic architecture (VSA): mental states are vectors storing structured information and manipulated using algebraic operations. Furthermore, the operations needed by QP match those in other VSAs. This allows existing biologically realistic neural models to be adapted to provide a mechanistic explanation of the cognitive phenomena described in the target article by Pothos & Busemeyer (P&B).

Confused ideas about the weirdness of quantum mechanics have sometimes been blamed for the spread of anti-realist positions in philosophy. In this seminar, I shall re-examine the relation between realism and quantum theory. My goal is to argue that one can remain a realist in a reasonably familiar sense, while adopting a theory which amounts to a form of idealism. After sketching the abstract mathematical structure of quantum theory, I will introduce realism and consider some (...) of its problems and some counter-arguments. Next I will look at why quantum theory needs an interpretation and at some of the features common to many proposed interpretations. Then I will discuss some of the gaps in decoherence theory, when it is considered as an interpretation of quantum theory, and I will end with a sketch of my own realist version of idealism in which the fundamental entities are structures which define minds, and the fundamental laws govern the stochastic developments of those structures. (shrink)

Quantum entanglement poses a challenge to the traditional metaphysical view that an extrinsic property of an object is determined by its intrinsic properties. So structural realists might be tempted to cite quantum entanglement as evidence for structural realism. I argue, however, that quantum entanglement undermines structural realism. If we classify two entangled electrons as a single system, we can say that their spin properties are intrinsic properties of the system, and that we can have knowledge (...) about these intrinsic properties. Specifically, we can know that the parts of the system are entangled and spatially separated from each other. In addition, the concept of supervenience neither illuminates quantum entanglement nor helps structural realism. (shrink)

Abstract Quantum mechanics has seemed to defy all attempts to construe it realistically, but antirealism, like the many?worlds hypothesis, is even more difficult to accept. In order to give a realist construal of quantum mechanics, we need first to distinguish the objective and rational aspect of reality from the paradigmatic thing?like aspects of having determinate physical properties: quantum?mechanical entities may be real in the former sense though not in the latter. Anti?realist arguments are based on the difficulty (...) of giving an account of quantum?mechanical collapse and the apparent superluminal velocities involved. Objections to superluminal velocities on the score of the special theory of relativity are found not to be conclusive, and the price?there being some preferred frame of reference?to be acceptable. A sketch of a probabilistic account of quantum?mechanical collapse is offered, which makes the difference between the macro? and the micro?world a matter of degree rather than kind. If that, or some other, account proved acceptable, we could be quantum?mechanical realists, though quantum?mechanical reality would be very different from that of material objects in hardware shops. (shrink)

Quantum mechanics, and classical mechanics, are framework theories that incorporate many different concrete theories which in general cannot be arranged in a neat hierarchy, but discussion of ‘the ontology of quantum mechanics’ tends to proceed as if quantum mechanics were a single concrete theory, specifically the physics of nonrelativistically moving point particles interacting by long-range forces. I survey the problems this causes and make some suggestions for how a more physically realistic perspective ought to influence the metaphysics (...) of quantum mechanics. (shrink)

First, this article considers the nature of quantum reality and the concept of realism in quantum theory, in conjunction with the roles of locality, causality, and probability and statistics there. Second, it offers two interpretations of quantum mechanics, developed by the authors of this article, the second of which is also a different theory of quantum phenomena. Both of these interpretations are statistical. The first interpretation, by A. Plotnitsky, “the statistical Copenhagen interpretation,” is nonrealist, insofar (...) as the description or even conception of the nature of quantum objects and processes is precluded. The second, by A. Khrennikov, is ultimately realist, because it assumes that the quantum-mechanical level of reality is underlain by a deeper level of reality, described, in a realist fashion, by a model, based in the pre-quantum classical statistical field theory, the predictions of which reproduce those of quantum mechanics. Moreover, because the continuous fields considered in this model are transformed into discrete clicks of detectors, experimental outcomes in this model depend on the context of measurement in accordance with N. Bohr’s interpretation and the statistical Copenhagen interpretation, which coincides with N. Bohr’s interpretation in this regard. (shrink)

In this new edition, Arthur Fine looks at Einstein's philosophy of science and develops his own views on realism. A new Afterword discusses the reaction to Fine's own theory. "What really led Einstein . . . to renounce the new quantum order? For those interested in this question, this book is compulsory reading."--Harvey R. Brown, American Journal of Physics "Fine has successfully combined a historical account of Einstein's philosophical views on quantum mechanics and a discussion of some (...) of the philosophical problems associated with the interpretation of quantum theory with a discussion of some of the contemporary questions concerning realism and antirealism. . . . Clear, thoughtful, [and] well-written."--Allan Franklin, Annals of Science "Attempts, from Einstein's published works and unpublished correspondence, to piece together a coherent picture of 'Einstein realism.' Especially illuminating are the letters between Einstein and fellow realist Schrodinger, as the latter was composing his famous 'Schrodinger-Cat' paper."--Nick Herbert, New Scientist "Beautifully clear. . . . Fine's analysis is penetrating, his own results original and important. . . . The book is a splendid combination of new ways to think about quantum mechanics, about realism, and about Einstein's views of both."--Nancy Cartwright, Isis. (shrink)

It is widely held that quantum mechanics is the first scientific theory to present scientifically internal, fundamental difficulties for a realistic interpretation (in the philosophical sense). The standard (Copenhagen) interpretation of the quantum theory is often described as the inevitable instrumentalistic response. It is the purpose of the present article to argue that quantum theory doesnot present fundamental new problems to a realistic interpretation. The formalism of quantum theory has the same states—it will be argued—as the (...) formalisms of older physical theories and is capable of the same kinds of philosophical interpretation. This result is reached via an analysis of what it means to give a realistic interpretation to a theory. The main point of difference between quantum mechanics and other theories—as far as the possibilities of interpretation are concerned—is the special treatment given tomeasurement by the “projection postulate.” But it is possible to do without this postulate. Moreover, rejection of the projection postulate does not, in spite of what is often maintained in the literature, automatically lead to the many-worlds interpretation of quantum mechanics. A realistic interpretation is possible in which only the reality ofone (our) world is recognized. It is argued that the Copenhagen interpretation as expounded by Bohr is not in conflict with the here proposed realistic interpretation of quantum theory. (shrink)

It is argued that a realistic interpretation of quantum mechanics is possible and useful. Current interpretations, from “Copenhagen” to “many worlds” are critically revisited. The difficulties for intuitive models of quantum physics are pointed out and possible solutions proposed. In particular the existence of discrete states, the quantum jumps, the alleged lack of objective properties, measurement theory, the probabilistic character of quantum physics, the wave–particle duality and the Bell inequalities are analyzed. The sketch of a realistic (...) picture of the quantum world is presented. It rests upon the assumption that quantum mechanics is a stochastic theory whose randomness derives from the existence of vacuum fields. They correspond to the vacuum fluctuations of quantum field theory, but taken as real rather than virtual. (shrink)

Different realistic attitudes towards wavefunctions and quantum states are as old as quantum theory itself. Recently Pusey, Barret and Rudolph on the one hand, and Auletta and Tarozzi on the other, have proposed new interesting arguments in favor of a broad realistic interpretation of quantum mechanics that can be considered the modern heir to some views held by the fathers of quantum theory. In this paper we give a new and detailed presentation of such arguments, propose (...) a new taxonomy of different realistic positions in the foundations of quantum mechanics and assess the scope, within this new taxonomy, of these realistic arguments. (shrink)

In a recent paper [3] Arroyo and Arenhart presented a detailed critical analysis regarding some essential aspects of representational realism and the logos approach to Quantum Mechanics (QM) addressed in terms of i) “a diagnosis of what is wrong with currently available solutions”; ii) “a proposal of a new methodology for addressing the problem”; and finally, iii) “a positive proposal to answer the question, which is arrived at by following the methodology suggested.” In this work we provide a (...) detailed reply to some deep misunderstandings that arise in this presentation and which, in turn, allow Arroyo and Arenhart to conclude that “contrarily to what de Ronde has suggested, his proposal is not a way to avoid commitment to uncritical images of reality, but rather, one further position in the already huge cart of options of quantum mechanics.” After providing a more accurate account of our diagnosis, we continue to address our methodology which —like that of Einstein, Heisenberg, Pauli and Schrödinger— goes back to the Greek-Modern account of physics. We then present our proposal grounded on the invariant-objective search for theoretical unity and discuss why intensive powers of action cannot be considered in dispositional or teleological terms with respect to actuality. Finally, we list some of the main results already accomplished by the logos approach and discuss the essential role of ‘intuition’ and ‘understanding’ within the realist setting. (shrink)

A new paradox of quantum mechanics has recently been proposed by an author claiming that any attempt to inject realism in physical theory is bound to lead to inconsistencies. In this paper we show that the mentioned paradox is not such a one and that at present there are no reasons to reject realism.