The development of a compositional model shows the incoherence of such notions as levels of being and both bottom-up and top-down causality. The mathematization of nature through the partial considerations of physics qua quantities is seen to lead to Pythagoreanism, if what is not included in the partial consideration is denied. An ontology of only probabilities, if not Pythagoreanism, is equivalent to a world of primitive dispositionalities. Problems are found with each. There is a need for properties as well as (...) quantities and these properties must be qualitative as well as dispositional. So there is a need for physical qualia (qualities) for the depiction of the intrinsic character of the finest interstices of nature. (shrink)

I maintain that quantum mechanics is fundamentally about a system of N particles evolving in three-dimensional space, not the wave function evolving in 3N-dimensional space.

Faced with realist-resistant sciences and the no-nonsense attitude of the times realism has moved away from the rather grandiose program that had traditionally been characteristic of its school. The objective of the shift seems to be to protect some doctrine still worthy of the "realist" name. The strategy is to relocate the school to where conditions seem optimal for its defense, and then to insinuate that the case for such a " piecemeal realism" could be made elsewhere too, were there (...) but world enough and time. The burden of this paper is to examine this piecemeal approach and to show why, despite the relocation, it cannot escape the difficulties of its grander cousins. For that purpose I begin with some brief historical reminders, and with a quick review of the state of the argument before realism went to pieces. This will help us see what has been abandoned in realism's flight, and what baggage still remains. (shrink)

How confident does the history of science allow us to be about our current well-tested scientific theories, and why? The scientific realist thinks we are well within our rights to believe our best-tested theories, or some aspects of them, are approximately true.2 Ambitious arguments have been made to this effect, such as that over historical time our scientific theories are converging to the truth, that the retention of concepts and claims is evidence for this, and that there can be no (...) other serious explanation of the success of science than that its theories are approximately true. There is appeal in each of these ideas, but making such strong claims has tended to be hazardous, leaving us open to charges that many typical episodes in the history of science just do not fit the model. (See, e.g., Laudan 1981.) Arguing for a realist attitude via general claims – properties ascribed to sets of theories, trends we see in progressions of theories, and claimed links between general properties like success and truth that apply or fail to apply to any theory regardless of its content – is like arguing for or via a theory of science, which brings with it the obligation to defend that theory. I think a realist attitude toward particular scientific theories for which we have evidence can be maintained rationally without such a theory, even in the face of the pessimistic induction over the history of science. The starting point at which questions arise as to what we have a right to believe about our theories is one where we have theories and evidence for them, and we are involved in the activity of apportioning our belief in each particular theory or hypothesis in accord with the strength of the particular evidence.3 The devil’s advocate sees our innocence and tries his best to sow seeds of doubt. If our starting point is as I say, though, the innocent believer in particular theories does not have to play offense and propose sweeping views about science in general, but only to respond to the skeptic’s challenges; the burden of initial argument is on the skeptic.. (shrink)

We study the EPR-type correlations from the perspective of the relational interpretation of quantum mechanics. We argue that these correlations do not entail any form of “non-locality”, when viewed in the context of this interpretation. The abandonment of strict Einstein realism implied by the relational stance permits to reconcile quantum mechanics, completeness, (operationally defined) separability, and locality.

This essay is a discussion of the philosophical and foundational issues that arise in non-relativistic quantum theory. After introducing the formalism of the theory, I consider: characterizations of the quantum formalism, empirical content, uncertainty, the measurement problem, and non-locality. In each case, the main point is to give the reader some introductory understanding of some of the major issues and recent ideas.

The underdetermination of theory by evidence must be distinguished from holism. The latter is a doctrine about the testing of scientific hypotheses; the former is a thesis about empirically adequate logically incompatible global theories or "systems of the world". The distinction is crucial for an adequate assessment of the underdetermination thesis. The paper shows how some treatments of underdetermination are vitiated by failure to observe this distinction, and identifies some necessary conditions for the existence of multiple empirically equivalent global theories. (...) We consider how empiricists should respond to the possibility of such systems of the world. (shrink)

Preanalytically, we are all scientific realists. But both philosophers and scientists become uncomfortable when forced into analysis. In the case of scientists, this discomfort often arises from practical difficulties in setting out a carefully described set of objects which adequately account for the phenomena with which they are concerned. This paper offers a set of representative examples of these difficulties for contemporary physicists. These examples challenge the traditional realist vision of mature scientific activity as struggling toward an ontologically well-defined world (...) picture. They challenge antirealist alternatives as well. (shrink)

I argue that space has three dimensions, and quantum mechanics does not show otherwise. Specifically, I argue that the mathematical wave function of quantum mechanics corresponds to a property that an N-particle system has in three-dimensional space.

: An examination of two thought experiments in contemporary physics reveals that the same thought experiment can be reanalyzed from the perspective of different and incompatible theories. This fact undermines those accounts of thought experiments that claim their justificatory power comes from their ability to reveal the laws of nature. While thought experiments do play a genuine evaluative role in science, they do so by testing the nonempirical virtues of a theory, such as consistency and explanatory power. I conclude that, (...) while their interpretation presupposes a whole set of background theories and putative laws, thought experiments nonetheless can evolve and be retooled for different theories and ends. (shrink)

Epistemologists have recently debated whether understanding is a species of knowledge. However, because they have offered little in the way of a detailed analysis of understanding, they lack the resources to resolve this issue. In this paper, I propose that S understands why p if and only if S has the non-Gettierised true belief that p, and for some proposition q, S has the non-Gettierised true belief that q is the best available explanation of p, S can correctly explain p (...) with q, and S can identify the features that make q the best explanation of p. On this analysis, understanding is reducible to knowing that p and that q is the best available explanation of p. (shrink)

This review of recent work in the philosophy of science motivated by a commitment to 'naturalism' begins by identifying three key axioms and one theorem shared by philosophers thus self-styled. Owing much to Quine and Ernest Nagel, these philosophers of science share a common agenda with naturalists elsewhere in philosophy. But they have disagreed among themselves about how the axioms and the theorems they share settle long-standing disputes in the philosophy of science. After expounding these disagreements in the work of (...) Boyd, Giere, Laudan, and Kitcher, I argue that naturalism needs to look for more than mere consistency in its foundations. (shrink)

Einstein regarded as one of the triumphs of his 1915 theory of gravity - the general theory of relativity - that it vindicated the action-reaction principle, while Newtonian mechanics as well as his 1905 special theory of relativity supposedly violated it. In this paper we examine why Einstein came to emphasise this position several years after the development of general relativity. Several key considerations are relevant to the story: the connection Einstein originally saw between Mach's analysis of inertia and both (...) the equivalence principle and the principle of general covariance, the waning of Mach's influence owing to de Sitter's 1917 results, and Einstein's detailed correspondence with Moritz Schlick in 1920. (shrink)

We discuss Russell's 1913 essay arguing for the irrelevance of the idea of causation to science and its elimination from metaphysics as a precursor to contemporary philosophical naturalism. We show how Russell's application raises issues now receiving much attention in debates about the adequacy of such naturalism, in particular, problems related to the relationship between folk and scientific conceptual influences on metaphysics, and to the unification of a scientifically inspired worldview. In showing how to recover an approximation to Russell's conclusion (...) while explaining scientists' continuing appeal to causal ideas (without violating naturalism by philosophically correcting scientists) we illustrate a general naturalist strategy for handling problems around the unification of sciences that assume different levels of naïveté with respect to folk conceptual frameworks. We do this despite rejecting one of the premises of Russell's argument, a version of reductionism that was scientifically plausible in 1913 but is not so now. (shrink)

Classical and quantum field theory provide not only realistic examples of extant notions of empirical equivalence, but also new notions of empirical equivalence, both modal and occurrent. A simple but modern gravitational case goes back to the 1890s, but there has been apparently total neglect of the simplest relativistic analog, with the result that an erroneous claim has taken root that Special Relativity could not have accommodated gravity even if there were no bending of light. The fairly recent acceptance of (...) nonzero neutrino masses shows that widely neglected possibilities for nonzero particle masses have sometimes been vindicated. In the electromagnetic case, there is permanent underdetermination at the classical and quantum levels between Maxwell's theory and the one-parameter family of Proca's electromagnetisms with massive photons, which approximate Maxwell's theory in the limit of zero photon mass. While Yang–Mills theories display similar approximate equivalence classically, quantization typically breaks this equivalence. A possible exception, including unified electroweak theory, might permit a mass term for the photons but not the Yang–Mills vector bosons. Underdetermination between massive and massless (Einstein) gravity even at the classical level is subject to contemporary controversy. (shrink)

Neo-positivism is dead. Let that imperfect designation stand for the project that dominated and defined the philosophy of science, especially in its Anglophone form, during the fifty or so years following the end of the Second World War. While its critics were many,1 its death was slow, and some think still to find a pulse.2 But die it did in the cul-de-sac into which it was led by its own faulty compass.

This paper describes Heidegger as a robust scientific realist, explains why his view has received such conflicting treatment, and concludes that the special significance of his position lies in his insistence upon linking the discussion of science to the question of its relation with technology. It shows that Heidegger, rather than accepting the usual forced option between realism and antirealism, advocates a realism in which he embeds the antirealist thesis that the idea of reality independent of human understanding is unintelligible. (...) This reading is defended against Rorty's antirealist interpretation, as well as Dreyfus' depiction of him as a deflationary realist, and his assessment of background realism is contrasted with Fine's. Further, the robustness of Heidegger's realism is laid out across several texts from 1912 to 1976, in order to show that he is neither an instrumental realist nor an internal realist. Finally, the point is made that the development of his view concerning realism gives rise to a critique of objectivity that is now being similarly advocated by numerous thinkers from a variety of disciplines, and that this critique is inevitably ethical and political. (shrink)

This essay has two main claims about EPR’s Reality Criterion. First, we claim that the application of the Reality Criterion makes an essential difference between the EPR argument and Einstein’s later arguments against quantum mechanics. We show that while the EPR argument, making use of the Reality Criterion, does derive that certain interpretations of quantum mechanics are incomplete, Einstein’s later arguments, making no use of the Reality Criterion, do not prove incompleteness, but rather point to the inadequacy of the Copenhagen (...) interpretation. We take this fact as an indication that the Reality Criterion is a crucial, indispensable component of the incompleteness argument(s). The second claim is more substantive. We argue that the Reality Criterion is a special case of the Common Cause Principle. Finally, we relate this proposal to Tim Maudlin’s recent assertion that the Reality Criterion is an analytic truth. (shrink)

The issue of realism about the physical world is distinct from the semantic issue of correspondence truth. So it is an aberration to identify the two issues (Dummett), to dismiss the realism issue out of hostility to correspondence truth (Rorty, Fine), to think that that issue is one of interpretation, or to argue against realism by criticizing various claims about truth and reference (Putnam, Laudan). It is also an aberration to identify realism with nonskepticism, truth-as-the-aim-of-science, or scientific convergence. Realism is (...) an overarching metaphysical issue which should be settled before any of these epistemic and semantic issues. (shrink)

I show why old and new claims on the role of counterfactual reasoning for the EPR argument and Bell’s theorem are unjustified: once the logical relation between locality and counterfactual reasoning is clarified, the use of the latter does no harm and the nonlocality result can well follow from the EPR premises. To show why, after emphasizing the role of incompleteness arguments that Einstein developed before the EPR paper, I critically review more recent claims that equate the use of counterfactual (...) reasoning with the assumption of a strong form of realism and argue that such claims are untenable. (shrink)

There is confusion among scholars of Bohr as to whether he should be categorized as an instrumentalist (see Faye 1991) or a realist (see Folse 1985). I argue that Bohr is a realist, and that the confusion is due to the fact that he holds a very special view of realism, which did not coincide with the philosophers’ views. His approach was sometimes labelled instrumentalist and other times realist, because he was an instrumentalist on the theoretical level, but a realist (...) on the level of models. Such a realist position is what I call phenomenological realism. In this paper, and by taking Bohr’s debate with Einstein as a paradigm, I try to prove that Bohr was such a realist. (shrink)

In earlier work, I criticized de Regt’s contextual theory of understanding, and advertised the advantages of my own, knowledge-based account. Using the early history of the standard model in particle physics as an illustration, I instead consider the benefits of unifying these two accounts of understanding. I argue that de Regt’s account substantially improves my own account of explanatory consideration, and that my account of explanatory comparison substantially improves upon his account of explanatory evaluation. De Regt and my apparent disagreement (...) about the so-called factivity of understanding is defused through a voluntaristic approach to the scientific realism debates. (shrink)

In this paper, we discuss various aspects of Heisenberg’s thought on hidden variables in the period 1927–1935. We also compare Heisenberg’s approach to others current at the time, specifically that embodied by von Neumann’s impossibility proof, but also views expressed mainly in correspondence by Pauli and by Schroedinger. We shall base ourselves mostly on published and unpublished materials that are known but little-studied, among others Heisenberg’s own draft response to the EPR paper. Our aim will be not only to clarify (...) Heisenberg’s thought on the hidden-variables question, but in part also to clarify how this question was understood more generally at the time. (shrink)

Truth is a fundamental philosophical concept that, despite its common and everyday use, has resisted common-sense formulations. At this point, one may legitimately wonder if there even is a common-sense notion of truth or what it could look like. In response, I propose here a common-sense account of truth based on four “truisms” that set a baseline for how to go about building an account of truth. Drawing on both ordinary language philosophy and contemporary pragmatic approaches to truth, I defend (...) a pragmatic, common-sense theory of truth. The result is a theory that focuses the use and function of truth while also emphasizing its “subject-independence.”. (shrink)

This essay offers a discussion and contextualisation of a series of letters exchanged between Jordi Cat and Paul Feyerabend from 1989 to 1994. These letters provide insights into Feyerabend’s later thought on a variety of themes including quantum holism, the disunity of science, the development of logical empiricism, and science activism. In doing so, we provide some original analysis and exegesis of Feyerabend’s evolving views on scientific methodology and quantum mechanics by focusing on Feyerabend’s changing attitudes towards Bohm, Bohr, and (...) his eventual colleague Hans Primas and his later sympathies with the algebraic approach. We also highlight Feyerabend’s role in the growth of the Disunity of Science movement and how he connected disunity to practical considerations in the philosophy of action. (shrink)

The present study attempts to provide a consistent and coherent account of what the world could be like, given the conceptual framework and results of contemporary quantum theory. It is suggested that standard quantum mechanics can, and indeed should, be understood as a realist theory within its domain of application. It is pointed out, however, that a viable realist interpretation of quantum theory requires the abandonment or radical revision of the classical conception of physical reality and its traditional philosophical presuppositions. (...) It is argued, in this direction, that the conceptualization of the nature of reality, as arising out of our most basic physical theory, calls for a kind of contextual realism. Within the domain of quantum mechanics, knowledge of 'reality in itself', 'the real such as it truly is' independent of the way it is contextualized, is impossible in principle. In this connection, the meaning of objectivity in quantum mechanics is analyzed, whilst the important question concerning the nature of quantum objects is explored. (shrink)

Standard quantum mechanics undeniably violates the notion of separability that classical physics accustomed us to consider as valid. By relating the phenomenon of quantum nonseparability to the all-important concept of potentiality, we effectively provide a coherent picture of the puzzling entangled correlations among spatially separated systems. We further argue that the generalized phenomenon of quantum nonseparability implies contextuality for the production of well-defined events in the quantum domain, whereas contextuality entails in turn a structural-relational conception of quantal objects, viewed as (...) carriers of dispositional properties. It is finally suggested that contextuality, if considered as a conditionalization preparation procedure of the object to be measured, naturally leads to a separable concept of reality whose elements are experienced as distinct, well-localized objects having determinate properties. In this connection, we find it necessary to distinguish the meaning of the term reality from the criterion of reality for us. The implications of the latter considerations for the notion of objectivity in quantum mechanics are also discussed. (shrink)

It is shown how the development of physics has involved making explicit what were homocentric projections which had heretofore been implicit, indeed inexpressible in theory. This is shown to support a particular notion of the invariant as the real. On this basis the divergence in ideals of physical intelligibility between Bohr and Einstein is set out. This in turn leads to divergent, but explicit, conceptions of objectivity and completeness for physical theory. *I am indebted to Dr. G. McLelland. Professor F. (...) Rohrlich and an anonymous referee of this journal for several improvements in the formulation of the paper. (shrink)

Bell’s theorem is purported to demonstrate the impossibility of a local “hidden variable” theory underpinning quantum mechanics. It relies on the well-known assumption of ‘locality’, and also on a little-examined assumption called ‘statistical independence’ (SI). Violations of this assumption have variously been thought to suggest “backward causation”, a “conspiracy” on the part of nature, or the denial of “free will”. It will be shown here that these are spurious worries, and that denial of SI simply implies nonlocal correlation between spacelike (...) degrees of freedom. Lorentz-invariant theories in which SI does not hold are easily constructed: two are exhibited here. It is conjectured, on this basis, that quantum-mechanical phenomena may be modeled by a local theory after all. (shrink)

This paper argues against the possibility of presenting a consistent version of the Copenhagen Interpretation of Quantum Physics, characterizing its founders' philosophical pronouncements including those on the realism-antirealism issue, as a contingent collection of local, often contradictory, moves in changing theoretical and sociopolitical circumstances. The paper analyzes the fundamental differences of opinion between Bohr and the mathematical physicists, Heisenberg and Born, concerning the foundational doctrine of the "indispensability of classical concepts", and their related disagreements on "quantum reality." The paper concludes (...) with an explanation of how the appearance of consensus was achieved despite fundamental disagreements among the proponents. The paper undermines the adequacy of the notion of a general conceptual framework to describe the philosophical endeavors of working scientists. (shrink)

Gerald Holton has famously described Einstein’s career as a philosophical “pilgrimage”. Starting on “the historic ground” of Machian positivism and phenomenalism, following the completion of general relativity in late 1915, Einstein’s philosophy endured (a) a speculative turn: physical theorizing appears as ultimately a “pure mathematical construction” guided by faith in the simplicity of nature and (b) a realistic turn: science is “nothing more than a refinement ”of the everyday belief in the existence of mind-independent physical reality. Nevertheless, Einstein’s mathematical constructivism (...) that supports his unified field theory program appears to be, at first sight, hardly compatible with the common sense realism with which he countered quantum theory. Thus, literature on Einstein’s philosophy of science has often struggled in finding the thread between ostensibly conflicting philosophical pronouncements. This paper supports the claim that Einstein’s dialog with Émile Meyerson from the mid 1920s till the early 1930s might be a neglected source to solve this riddle. According to Einstein, Meyerson shared (a) his belief in the independent existence of an external world and (b) his conviction that the latter can be grasped only by speculative means. Einstein could present his search for a unified field theory as a metaphysical-realistic program opposed to the positivistic-operationalist spirit of quantum mechanics. (shrink)

Philosophers of biology typically pose questions about individuation by asking “what is an individual?” For example, we ask, “what is an individual species”, “what is an individual organism”, and “what is an individual gene?” In the first part of this chapter, I present my account of the gene concept and how it is used in investigative practices in order to motivate a more pragmatic approach. Instead of asking “what is a gene?”, I ask: “how do biologists individuate genes?”, “for what (...) purposes?”, and “do their practices of individuating genes serve these purposes?" In the second part of this chapter, I propose that we use this approach when analyzing concepts of organisms and biological individuals. Following philosophical pragmatism, I argue that we should abstain from attempts to situate individuation of Darwinian individuals or of holobionts in a philosophy of nature. Instead, we should analyze practices of individuating organisms in terms of three-place relations between the world, ideas, and human purposes and actions. I conclude with three lessons: an ontological, an epistemological, and a meta-philosophical lesson, which I suggest, apply to philosophy of science generally and to philosophy and metaphysics at large. (shrink)

The authors survey some debates about the nature and structure of physical theories and about the connections between our physical theories and naturalized metaphysics. The discussion is organized around an “ideal view” of physical theories and criticisms that can be raised against it. This view includes controversial commitments regarding the best analysis of physical modalities and intertheory relations. The authors consider the case in favor of taking laws as the primary modal notion, discussing objections related to alleged violations of the (...) laws, the apparent need to appeal to causality, and the status of probability. The “ideal view” includes a commitment that fundamental physical theories are explanatorily sufficient. The authors discuss several challenges to recovering the manifest image from fundamental physics, along with a distinct challenge to reductionism based on acknowledging the contributions of less fundamental theories in physical explanations. (shrink)

Quantum Theory, similar to Relativity Theory, requires a new concept of space-time, imposed by a universal constant. While velocity of lightcnot being infinite calls for a redefinition of space-time on large and cosmological scales, quantization of action in terms of a finite, i.e. non vanishing, universal constanthrequires a redefinition of space-time on very small scales. Most importantly, the classical notion of “time”, as one common continuous time variable and nature evolving continuously “in time”, has to be replaced by an infinite (...) manifold of transition rates for discontinuous quantum transitions. The fundamental laws of quantum physics, commutation relations and quantum equations of motion, resulted from Max Born’s recognition of the basic principle of quantum physics:To each change in nature corresponds an integer number of quanta of action. Action variables may only change by integer values ofh, requiring all other physical quantities to change by discrete steps, “quantum jumps”. The mathematical implementation of this principle led to commutation relations and quantum equations of motion. The notion of “point” in space-time looses its physical significance; quantum uncertainties of time, position, just as any other physical quantity, are necessary consequences of quantization of action. (shrink)

This survey of major developments in North American philosophy of science begins with the mid-1960s consolidation of the disciplinary synthesis of internalist history and philosophy of science (HPS) as a response to criticisms of logical empiricism. These developments are grouped for discussion under the following headings: historical metamethodologies, scientific realisms, philosophies of the special sciences, revivals of empiricism, cognitivist naturalisms, social epistemologies, feminist theories of science, studies of experiment and the disunity of science, and studies of science as practice and (...) culture. A unifying theme of the survey is the relation between historical metamethodologists and scientific realists, which dominated philosophical work in the late 1970s. I argue that many of the alternative cognitive naturalisms, social epistemologies, and feminist theories that have been proposed can be understood as analogues to the differences between metamethodological theories of scientific rationality and realist accounts of successful reference to real causal processes. Recent work on experiment, scientific practice, and the culture of science may, however, challenge the underlying conception of the field according to which realism and historical rationalism (or their descendants) are the important alternatives available, and thus may take philosophy of science in new directions. (shrink)

Many thought experiments are used to probe theoretical statements. One crucial strategy for doing this, or so I will argue, is the following. A TE reveals an inconsistency in part of our previously held, sometimes empirically well-established, theoretical statements. A TEer or her critic then proposes a resolution in the form of a conjecture, a hypothesis that merits further investigation. To explore this characterisation of the epistemic function of such TEs, I clarify the nature of the inconsistencies revealed by TEs, (...) and how TEs reveal and resolve them. I argue that this can be done without settling the question of which cognitive processes are involved in performing a TE; be they propositional or non-propositional. The upshot is that TEs’ reliability, like real experiments, is to be found, in part, in their replicability by the epistemic community, not in their cognitive underpinnings. (shrink)

I discuss the interpretation of spontaneous collapse theories, with particular reference to Bell's suggestion that the stochastic jumps in the evolution of the wave function should be considered as local beables of the theory. I develop this analogy in some detail for the case of non-relativistic GRW-type theories, using a generalisation of Bell's notion of beables to POV measures. In the context of CSL-type theories, this strategy appears to fail, and I discuss instead Ghirardi and co-workers' mass-density interpretation and its (...) relation to Schrödinger's original charge-density interpretation. This discussion is extended to relativistic CSL-type theories. A few remarks on Everett's interpretation conclude the paper. (shrink)

“Scientific theories are maps of the natural world.” This metaphor is often used as part of a deflationary argument for a weak but relatively global version of scientific realism, a version that recognizes the place of conventions, goals, and contingencies in scientific representations, while maintaining that they are typically true in a clear and literal sense. By examining, in a naturalistic way, some relationships between maps and what they map, we question the scope and value of realist construals of maps—and (...) by extension of scientific representations. Deflationary philosophy of science requires more variegated stances. (shrink)

Van Fraassen has argued that many philosophical positions should be understood as stances rather than factual beliefs. In this paper I discuss the vexed question of whether and how such stances can be rationally justified. Until this question has been satisfactorily answered, the otherwise promising stance approach cannot be considered a viable metaphilosophical option. One can find hints, and the beginnings of an answer to this question, in van Fraassen’s (and others’) writings, but no general, fully clear and convincing account (...) has been offered. I aim to provide such an account. In the first section I introduce the concept of a stance. In the second section I argue that stances may be justified pragmatically, in terms of both their epistemic fruits, and their coherence with values. In the third section I further consider the relationship between stances and values, arguing that the value-ladenness of a stance does not render it immune to rational scrutiny. In the final section I look at van Fraassen’s version of epistemological voluntarism, which plays a central role in his conception of the basis on which a stance may be rationally adopted. I show that voluntarism provides a theoretical framework, and approach to epistemology, within which the forms of justification appropriate to stance choice I outline in sections 2 and 3 find a natural home. (shrink)

QBism is one of the main candidates for an epistemic interpretation of quantum mechanics. According to QBism, the quantum state or the wavefunction represents the subjective degrees of belief of the agent assigning the state. But, although the quantum state is not part of the furniture of the world, quantum mechanics grasps the real via the Born rule which is a consistency condition for the probability assignments of the agent. In this paper, we evaluate the plausibility of recent criticism of (...) QBism. We focus on the consequences of the subjective character of the quantum state, the issue of realism and the problem of the evolution of the quantum state in QBism. In particular, drawing upon Born’s notion of invariance as the mark of the real, it is argued that there is no essential difference between Einstein’s program of ‘the real’ and QBists’ realism. Also, it will be argued that QBism can account for the unitary evolution of the quantum state. (shrink)

This paper offers a defense of backwards in time causation models in quantum mechanics. Particular attention is given to Cramer's transactional account, which is shown to have the threefold virtue of solving the Bell problem, explaining the complex conjugate aspect of the quantum mechanical formalism, and explaining various quantum mysteries such as Schrödinger's cat. The question is therefore asked, why has this model not received more attention from physicists and philosophers? One objection given by physicists in assessing Cramer's theory was (...) that it is not testable. This paper seeks to answer this concern by utilizing an argument that backwards causation models entail a fork theory of causal direction. From the backwards causation model together with the fork theory one can deduce empirical predictions. Finally, the objection that this strategy is questionable because of its appeal to philosophy is deflected. (shrink)

This paper analyses the early history of David Bohm’s mechanics from the perspective of Ludwik Fleck’s thought-collectives and shows how the thought-style of the scientific community limits the possible modes of thinking and what new possibilities for the construction of a new theory arise if these limits are removed.

Einstein’s unpublished 1927 deterministic trajectory interpretation of quantum mechanics is critically examined, in particular with regard to the reason given by Einstein for rejecting his theory. It is shown that the aspect Einstein found objectionable—the mutual dependence of the motions of particles when the (many-body) wavefunction factorises—is a generic attribute of his theory but that this feature may be removed by modifying Einstein’s method in either of two ways: using a suggestion of Grommer or, in a physically important special case, (...) using a simpler technique. It is emphasized though that the presence or absence of the interdependence property does not determine the acceptability of a trajectory theory. It is shown that there are other grounds for rejecting Einstein’s theory (and the two modified theories), to do with its domain of applicability and compatibility with empirical predictions. That Einstein’s reason for rejection is not a priori grounds for discarding a trajectory theory is demonstrated by reference to an alternative deterministic trajectory theory that displays similar particle interdependence yet is compatible with quantum predictions. (shrink)

This is a review of those key thought experiments in physics from the late 19th century onward that seem to have played a particular role in the process of the discovery or advancement of theory. Among others the paper discusses Maxwell's demon, several of Einstein's thought experiments in relativity, Heisenberg's microscope, the Einstein-Schrödinger cat, and the EPR thought experiment.

We propose a technical reformulation of the measurement problem of quantum mechanics, which is based on the postulate that the final state of a measurement is classical; this accords with experimental practice as well as with Bohr’s views. Unlike the usual formulation (in which the post-measurement state is a unit vector in Hilbert space), our version actually opens the possibility of admitting a purely technical solution within the confines of conventional quantum theory (as opposed to solutions that either modify this (...) theory, or introduce unusual and controversial interpretative rules and/or ontologies).To that effect, we recall a remarkable phenomenon in the theory of Schrödinger operators (discovered in 1981 by Jona-Lasinio, Martinelli, and Scoppola), according to which the ground state of a symmetric double-well Hamiltonian (which is paradigmatically of Schrödinger’s Cat type) becomes exponentially sensitive to tiny perturbations of the potential as ħ→0. We show that this instability emerges also from the textbook wkb approximation, extend it to time-dependent perturbations, and study the dynamical transition from the ground state of the double well to the perturbed ground state (in which the cat is typically either dead or alive, depending on the details of the perturbation).Numerical simulations show that adiabatically arising perturbations may (quite literally) cause the collapse of the wave-function in the classical limit. Thus, at least in the context of a simple mathematical model, we combine the technical and conceptual virtues of decoherence (which fails to solve the measurement problem but launches the key idea that perturbations may come from the environment) with those of dynamical collapse models à la grw (which do solve the measurement problem but are ad hoc), without sharing their drawbacks: single measurement outcomes are obtained (instead of merely diagonal reduced density matrices), and no modification of quantum mechanics is needed. (shrink)

I discuss changes of perspective of four kinds in science and about science. Section 2 defends a perspectival nonrealism—something akin to Giere’s perspectival realism but not a realism—against the idea of complete, “Copernican” objectivity. Section 3 contends that there is an inverse relationship between epistemological conservatism and scientific progress. Section 4 casts doubt on strong forms of scientific realism by taking a long-term historical perspective that includes future history. Section 5 defends a partial reversal in the status of so-called context (...) of discovery and context of justification. Section 6 addresses the question of how we can have scientific progress without scientific realism—how progress is possible without the accumulation of representational truth. The overall result is a pragmatic instrumentalist perspective on the sciences and how to study them philosophically, one that contains a kernel of realism—instrumental realism. (shrink)

In recent years a general consensus has been developing in the philosophy of science to the effect that strong social constructivist accounts are unable to adequately account for scientific practice. Recently, however, a number of commentators have formulated an attenuated version of constructivism that purports to avoid the difficulties that plague the stronger claims of its predecessors. Interestingly this attenuated form of constructivism finds philosophical support from a relatively recent turn in the literature concerning scientific realism. Arthur Fine and a (...) number of other commentators have argued that the realism debate ought to be abandoned. The rationale for this argument is that the debate is sterile for it has, it is claimed, no consequence for actual scientific practice, and therefore does not advance our understanding of science or its practice. Recent “softer” accounts of social constructivism also hold a similar agnostic stance to the realism question. I provide a survey of these various agnostic stances and show how they form a general position that I shall refer to as “the anti-philosophical stance”. I then demonstrate that the anti-philosophical stance fails by identifying difficulties that attend its proposal to ban philosophical interpretation. I also provide examples of instances where philosophical stances to the realism question affect scientific practice. (shrink)

Naturalism implies unity of method--an application of the methods of science to the methodology of science itself and to value theory. Epistemological naturalists have tried to find a privileged discipline to be the methodological model of philosophy of science and epistemology. However, since science itself is not unitary, the use of one science as a model amounts to a reduction and distorts the philosophy of science just as badly as traditional philosophy of science distorted science, despite the fact that the (...) central theme of naturalized philosophy of science is that methodology should be true to science as practiced. I argue that naturalized philosophy of science must apply a plurality of methods to epistemological issues. (shrink)