A Controlled Not variant of the standard quantum teleportation protocol affords a step-by-step analysis of what is, or can be said to be, achieved in the process in either location. Dominant interpretations of what quantum teleportation consists in and implies are reviewed in this light. Being mindful of the statistical significance of the terms and operations involved, as well as awareness of classical analogies, can help sort out what is specifically quantum-mechanical, and what is not, in so-called teleportation. What the (...) latter achieves appears to be the transmission, without the involvement of mysterious channels, of what a quantum state encapsulates: the multitiered probabilistic characterization of a given preparation, which might be all we can possibly know about a physical system in a given experimental situation. (shrink)

ABSTRACTAlexander Wendt’s Quantum Mind and Social Science is an effort to establish foundations of social science based on the ontology of modern physics. The quantum revolution has deservedly had repercussions in many sciences, but it is unwise to ground social science on physical theories, which are subject to constant revision. Additionally, despite its empirical success, there is no agreed-upon interpretation of quantum theory. Finally, even if there were, the random indeterminacy intrinsic to the quantum world cannot account for the intentionality (...) of human action. Intentional agents act for reasons, not at random; nor are the reasons chosen at random. (shrink)

The search for a coherent and fertile interpretation of quantum mechanics [QM] with collapse of the wave function is currently a hot topic. This paper focuses on the following sets of related issues: 1) In what sense, if any, do collapse theories constitute a view of the quantum world induced “from the practices-up”? [Here and throughout the paper the term “a view from the practices-up” will mean a view induced from the practices of scientists working on specific problems.] 2) What (...) general description does a collapse variant of QM yield of the physical world? What interpretative problems, if any, does it solve? How exactly does it differ from current mainstream versions of QM? What problems does it face? How serious are these problems in light of current background knowledge?. 3) In our present scientific and philosophical circumstances, what, if anything, makes the search for collapse theories an attractive program? (shrink)

Fritjof Capra's The Tao of Physics, one of several popularizations paralleling Eastern mysticism and modern physics, is critiqued, demonstrating that Capra gives little attention to the differing philosophies of physics he employs, utilizing whatever interpretation suits his purposes, without prior justification. The same critique is applied and similar conclusions drawn, about some recent attempts at relating theology and physics. In contrast, we propose the possibility of maintaining a cogent relationship between these disciplines by employing theological hypotheses to account for aspects (...) of physics that are free from interpretive difficulties, such as the ability to create mathematical structures with extraordinary predictive success. (shrink)

Quantum Theory and Humeanism have long been thought to be incompatible due to the irreducibility of the correlations involved in entangled states. In this paper, we reconstruct the tension between Humeanism and entanglement via the concept of causal structure, and provide a philosophical introduction to the ER=EPR conjecture. With these tools, we then show how the concept of causal structure and the ER=EPR conjecture allow us to resolve the conflict between Humeanism and entanglement.

After presenting Apostel’s views on scientific realism, I present definitions of the concepts of ontology and metaphysics. I then proceed to develop Apostel’s basic ontology and his metaphysics. Apostel proposed a particular understanding of existence based on his views on causation. He also developed a view of the universe as a causal self-explaining system. I discuss and illustrate three kinds of what he calls “metaphysical deductions” that aim to deliver such a view of the universe. The most important one is (...) the Leibnizian variational method, that should allow us to deduce the existing universe as the ‘best’ of all possible worlds. (shrink)

The condition of explicit theoretically discursive cognitive performance, as it culminates in scientific activity, is, I claim, the life world. I contrast life world and scientific world and argue that the latter arises from the first and that contrary to the prevailing views the scientific world (actually, worlds, since the classical world is substantially different from the quantum world) finds its completion in the life world and not the other way around. In other words: the closure we used to search (...) in a complete and comprehensive scientific description of all aspects of experience by referring it back to underlying atoms, genes and other scientific objects and the covering laws ruling them, should be sought in a reintegrating and occasionally dissolving of the abstract scientific model in the self-organizational fluidity and superposition-like indeterminateness and non-locality of the life world: “We have to acknowledge the indeterminate as a positive phenomenon” (Merleau-Ponty in his The Phenomenology of Perception). (shrink)

In this first section we start with defining the notions of inconsistency and para-consistency, we give an example of an inconsistency and clarify what according to us is the basic problem with respect to the occurrence of inconsistencies. We are then in a position to state the aim of this paper.

In much recent work, invariance under intervention has become a hallmark of the correctness of a causal-law claim. Despite its importance this thesis generally is either simply assumed or is supported by very general arguments with heavy reliance on examples, and crucial notions involved are characterized only loosely. Yet for both philosophical analysis and practicing science, it is important to get clear about whether invariance under intervention is or is not necessary or sufficient for which kinds of causal claims. Furthermore, (...) we need to know what counts as an intervention and what invariance is. In this paper I offer explicit definitions of two different kinds for the notions intervention, invariance, and causal correctness. Then, given some natural and relatively uncontroversial assumptions, I prove two distinct sets of theorems showing that invariance is indeed a mark of causality when the concepts are appropriately interpreted. (shrink)

Reichenbach worked in an era when philosophers were hopeful about the unity of science, and particularly about unity of method. He looked for universal tests of causal connectedness that could be applied across disciplines and independently of specific modeling assumptions. The hunt for quantum causes reminds us that his hopes were too optimistic. The mark method is not even a starter in testing for causal links between outcomes in E.P.R., because our background hypotheses about these links are too thin to (...) supply the kind of information we need to put the method into play. When we turn to conventional statistical methods, we have seen that one test proposed — robustness of the conditional probabilities — can be conclusive only when we know that there are no other causal factors at work. In the particular case of E.P.R., it has often been assumed that this antecedent question can be settled by applying Reichenbach's conjunctive fork condition. But that application is in no way free of further modeling assumptions. Cartwright (1989) has shown that the conjunctive fork is only a necessary condition on a common cause under very limiting restrictions (restrictions that take one far from the case of maximal commonality); and she has argued that these special conditions are not satisfied in E.P.R.Finally, even given the assumption that there are no other causes at work, the significance of robustness for E.P.R. is unclear. We need a model which tells us how one outcome would influence the other; without that, there is no way of interpreting the results of the robustness test so that it is decisive. In each of the approaches we discussed, Reichenbach provided the crucial guiding ideas that underlay our construction of a causality test; but the articulation of a specific criterion depends on the other details of the model. What is a criterion for a specific kind of link in one model need not be in another. We have illustrated with robustness and E.P.R., but we take the point to be perfectly general: there are no tests of causality outside of models which already have significant causal structure built in. (shrink)

I discuss various formulations of stochastic Einstein locality (SEL), which is a version of the idea of relativistic causality, that is, the idea that influences propagate at most as fast as light. SEL is similar to Reichenbach's Principle of the Common Cause (PCC), and Bell's Local Causality. My main aim is to discuss formulations of SEL for a fixed background spacetime. I previously argued that SEL is violated by the outcome dependence shown by Bell correlations, both in quantum mechanics and (...) in quantum field theory. Here I reassess those verdicts in the light of some recent literature which argues that outcome dependence does not violate the PCC. I argue that the verdicts about SEL still stand. Finally, I briefly discuss how to formulate relativistic causality if there is no fixed background spacetime. (shrink)

The violation of the Bell inequality means that measurement-results in the two wings of the experiment cannot be screened off from one another, in the sense of Reichenbach. But does this mean that there is causation between the results? I argue that it does, according to Lewis's counterfactual analysis of causation and his associated views. The reason lies in his doctrine that chances evolve by conditionalization on intervening history. This doctrine collapses the distinction between the conditional probabilities that are used (...) to state screening off, and the counterfactuals with chance consequents that are used to state lack of causation. I briefly discuss ways to evade my argument. (shrink)

I show that locality, as it occurs in EPR arguments for the incompleteness of quantum mechanics, can be construed as causal independence understood in terms of Lewis’ counterfactual analysis of causation. This construal has two benefits. It supplements recent analyses, which have not treated locality in detail. And it clarifies the relation between two EPR arguments that have recently been distinguished. It shows that the simpler of the two is more complex than has been thought; and that the other argument (...) does not need ‘counterfactual definiteness’.I aim to show that in the EPR argument (Einstein et al. 1935) for the incompleteness of quantum mechanics (QM), locality can be taken as causal independence, understood in terms of Lewis’ counterfactual analysis of causation.Recent analyses of the EPR argument makes this construal of locality timely, for two reasons. First, these analyses typically say little about locality. (shrink)

Reichenbach's interpretation of quantum mechanics has been narrowly reduced to the advocacy of a three‐valued logic. His interpretation rests, though, on the same rich epistemological framework that shapes his influential analysis of space‐time theories. Different interpretations of the quantum formalism, with their conflicting ontologies and causes, emerge in this view as “equivalent descriptions”. One casualty of the conventionalist approach is the measurement problem. I give reasons for why Reichenbach's view on the nature of interpretations of quantum theory cannot be defended.

It is well-known that developments of quantum mechanical states according to the Schrödinger equation during a measurement seem to prevent measurements from having definite results. For, the usually assumed (idealized) Schrödinger development of the measured object and the measuring apparatus during a measurement typically results in a state of the entire system which is a superposition of the eigenstates of the measured observable and measuring observable. And the most common interpretations of quantum mechanics state that an observable does not have (...) a definite value if the quantum mechanical state is a superposition of the eigenstates of the observable. Many ways out of this problem have been suggested. I want to discuss an interpretation suggested by S. Kochen (Kochen 1985), and suggest similar interpretations, each of which accept the universal validity of the Schrödinger equation, and yet yield definite results for measurements. (shrink)

The paper argues that on three out of eight possible hypotheses about the EPR experiment we can construct novel and realistic decision problems on which (a) Causal Decision Theory and Evidential Decision Theory conflict (b) Causal Decision Theory and the EPR statistics conflict. We infer that anyone who fully accepts any of these three hypotheses has strong reasons to reject Causal Decision Theory. Finally, we extend the original construction to show that anyone who gives any of the three hypotheses any (...) non-zero credence has strong reasons to reject Causal Decision Theory. However, we concede that no version of the Many Worlds Interpretation (Vaidman, in Zalta, E.N. (ed.), Stanford Encyclopaedia of Philosophy 2014) gives rise to the conflicts that we point out. (shrink)

It is a widespread belief that the Kochen-Specker theorem imposes a contextuality constraint on the ontology of beables in quantum hidden variables theories. On the other hand, after Bell’s influential critique, the importance of von Neumann’s wrongly called ‘impossibility proof’ has been severely questioned. However, Max Jammer, Jeffrey Bub and Dennis Dieks have proposed insightful reassessments of von Neumann’s theorem: what it really shows is that hidden variables theories cannot represent their beables by means of Hermitian operators in Hilbert space. (...) Hereby I show that i) the very same constraint can be derived from Gleason’s theorem, and that ii) if we consider the import of von Neumann’s and Gleason’s theorems, the relevance of the Kochen-Specker theorem for hidden variables theories gets substantially weakened: it does not force them to be contextual in any interesting sense of the term. (shrink)

We pursue a model-oriented rather than axiomatic approach to the foundations of Quantum Mechanics, with the idea that new models can often suggest new axioms. This approach has often been fruitful in Logic and Theoretical Computer Science. Rather than seeking to construct a simplified toy model, we aim for a 'big toy model', in which both quantum and classical systems can be faithfully represented—as well as, possibly, more exotic kinds of systems. To this end, we show how Chu spaces can (...) be used to represent physical systems of various kinds. In particular, we show how quantum systems can be represented as Chu spaces over the unit interval in such a way that the Chu morphisms correspond exactly to the physically meaningful symmetries of the systems—the unitaries and antiunitaries. In this way we obtain a full and faithful functor from the groupoid of Hubert spaces and their symmetries to Chu spaces. We also consider whether it is possible to use a finite value set rather than the unit interval; we show that three values suffice, while the two standard possibilistic reductions to two values both fail to preserve fullness. (shrink)

It is still a matter of controversy whether the Principle of the Common Cause (PCC) can be used as a basis for sound causal inference. It is thus to be expected that its application to quantum mechanics should be a correspondingly controversial issue. Indeed the early 90’s saw a flurry of papers addressing just this issue in connection with the EPR correlations. Yet, that debate does not seem to have caught up with the most recent literature on causal inference generally, (...) which has moved on to consider the virtues of a generalised PCC-inspired condition, the so-called Causal Markov Condition (CMC). In this paper we argue that the CMC is an appropriate benchmark for debating possible causal explanations of the EPR correlations. But we go on to take issue with some pronouncements on EPR by defenders of the CMC. (shrink)

Fifty years after the publication of Bell's theorem, there remains some controversy regarding what the theorem is telling us about quantum mechanics, and what the experimental violations of Bell inequalities are telling us about the world. This chapter represents my best attempt to be clear about what I think the lessons are. In brief: there is some sort of nonlocality inherent in any quantum theory, and, moreover, in any theory that reproduces, even approximately, the quantum probabilities for the outcomes of (...) experiments. But not all forms of nonlocality are the same; there is a distinction to be made between action at a distance and other forms of nonlocality, and I will argue that the nonlocality required to violate the Bell inequalities need not involve action at a distance. Furthermore, the distinction between forms of nonlocality makes a difference when it comes to compatibility with relativistic causal structure. (shrink)

Quantum mechanics portrays the universe as involving non-local influences that are difficult to reconcile with relativity theory. By postulating backward causation, retro-causal interpretations of quantum mechanics could circumvent these influences and accordingly reconcile quantum mechanics with relativity. The postulation of backward causation poses various challenges for the retro-causal interpretations of quantum mechanics and for the existing conceptual frameworks for analyzing counterfactual dependence, causation and causal explanation. In this chapter, we analyze the nature of time, causation and explanation in a local, (...) deterministic retro-causal interpretation of quantum mechanics that is inspired by Bohmian mechanics. This interpretation of quantum mechanics offers a deterministic, local ‘hidden-variables’ model of the Einstein-Podolsky-Rosen experiment that poses a new challenge for Reichenbach’s principle of the common cause. In this model, the common cause – the state of particles at the emission from the source – screens off the correlation between its effects – the distant measurement outcomes – but nevertheless fails to explain the correlation between the effects. (shrink)

In concluding his ‘Autobiographical notes’, Albert Einstein explained that the purpose of his exposition was to ‘show the reader how the efforts of a life hang together and why they have led to expectations of a definite form’. Einstein's remarks tell of a coherence between personal ‘strivings and searchings’ and scientific activity, which has all but vanished in the midst of the current trend of social constructivism in history of science. As Nancy Nersessian recently pointed out, in the process of (...) illuminating complex relationships between scientific activity and its social context, ‘socio-historical analysis has “black-boxed” the individual scientist’. Has the pendulum swung too far? In reaction to the preceding great-man hagiographie approach to the history of science, the social constructivists have largely ‘thrown the baby out with the bathwater’; consideration of individual scientists' personal approaches to science was unnecessarily expunged with the removal of ‘genius’ as an explanatory tool. (shrink)

This paper defends a counterfactual account of explanation, according to which successful explanation requires tracing patterns of counterfactual dependence of a special sort, involving what I call active counterfactuals. Explanations having this feature must appeal to generalizations that are invariant--stable under certain sorts of changes. These ideas are illustrated by examples drawn from physics and econometrics.

Is the common cause principle merely one of a set of useful heuristics for discovering causal relations, or is it rather a piece of heavy duty metaphysics, capable of grounding the direction of causation itself? Since the principle was introduced in Reichenbach’s groundbreaking work The Direction of Time (1956), there have been a series of attempts to pursue the latter program—to take the probabilistic relationships constitutive of the principle of the common cause and use them to ground the direction of (...) causation. These attempts have not all explicitly appealed to the principle as originally formulated; it has also appeared in the guise of independence conditions, counterfactual overdetermination, and, in the causal modelling literature, as the causal markov condition. In this paper, I identify a set of difficulties for grounding the asymmetry of causation on the principle and its descendents. The first difficulty, concerning what I call the vertical placement of causation, consists of a tension between considerations that drive towards the macroscopic scale, and considerations that drive towards the microscopic scale—the worry is that these considerations cannot both be comfortably accommodated. The second difficulty consists of a novel potential counterexample to the principle based on the familiar Einstein Podolsky Rosen (EPR) correlations in quantum mechanics. (shrink)

An analysis is made of Deutsch's recent claim to have derived the Born rule from decision-theoretic assumptions. It is argued that Deutsch's proof must be understood in the explicit context of the Everett interpretation, and that in this context, it essentially succeeds. Some comments are made about the criticism of Deutsch's proof by Barnum, Caves, Finkelstein, Fuchs, and Schack; it is argued that the flaw which they point out in the proof does not apply if the Everett interpretation is assumed.

This paper introduces the special issue The societal impact of the emerging quantum technologies as a contribution to a more inclusive societal debate on quantum technologies. It brings together five contributions. Three are authored by quantum technology researchers who give explorations of the possible impacts of quantum technologies on science, industry and society. The fourth contribution discusses within the framework of responsible research and innovation, the ways in which quantum technologies and the societal debate about them are presented in European (...) policy documents. The final contribution analyses how the popularisation of quantum theory for wider audiences has evolved, and can be improved, with the emergence of quantum technologies. This introduction is also a call for a renewed effort to make quantum theory understandable. A preamble to a societal debate about quantum technologies is that all stakeholders understand these technologies to a reasonable degree, and the current framing of quantum theory as enigmatic in not helpful to meeting this. It is argued that philosophers of physics can help overcome this framing by explaining how quantum theory and quantum technologies are similar to every-day descriptions and technologies. (shrink)

Counterfactuals in quantum theory are briefly reviewed and it is argued that they are very different from counterfactuals considered in the general philosophical literature. The issue of time symmetry of quantum counterfactuals is considered and a novel time-symmetric definition of quantum counterfactuals is proposed. This definition is applied for analyzing several controversies related to quantum counterfactuals.

Whilst a straightforward consequence of the formalism of non-relativistic quantum mechanics, the phenomenon of quantum teleportation has given rise to considerable puzzlement. In this paper, the teleportation protocol is reviewed and these puzzles dispelled. It is suggested that they arise from two primary sources: (1) the familiar error of hypostatizing an abstract noun (in this case, ‘information’) and (2) failure to differentiate interpretation dependent from interpretation independent features of quantum mechanics. A subsidiary source of error, the simulation fallacy, is also (...) identified. The resolution presented of the puzzles of teleportation illustrates the benefits of paying due attention to the logical status of ‘information’ as an abstract noun. Introduction The quantum teleportation protocol 2.1 Some information-theoretic aspects of teleportation 2.1.1 Preamble 2.1.2Application to teleportation The puzzles of teleportation Resolving (dissolving) the problem 4.1 The simulation fallacy The teleportation process under different interpretations 5.1 Collapse interpretations:Dirac/von Neumann, GRW 5.2 No collapse and no extra values: Everett 5.3 No collapse, but extra values: Bohm 5.3.1 A note on active information 5.4 Ensemble and statistical viewpoints Concluding remarks. (shrink)

A Hilbert-space model for quantum logic follows from space-time structure in theories with consistent state collapse descriptions. Lorentz covariance implies a condition on space-like separated propositions that if imposed on generally commuting ones would lead to the covering law, and such a generalization can be argued if state preparation can be conditioned to space-like separated events using EPR-type correlations. The covering law is thus related to space-time structure, though a final understanding of it, through a self-consistency requirement, will probably require (...) quantum space-time. (shrink)

Fine has recently proved the surprising result that satisfaction of the Bell inequality in a Clauser-Horne experiment implies the existence of joint probabilities for pairs of noncommuting observables in the experiment. In this paper we show that if probabilities are interpreted in the von Mises-Church sense of relative frequencies on random sequences, a proof of the Bell inequality is nonetheless possible in which such joint probabilities are assumed not to exist. We also argue that Fine's theorem and related results do (...) not impugn the common view that local realists are committed to the Bell inequality. (shrink)

I argue that the Causal Markov Condition (CMC) is in principle applicable to the Einstein–Podolsky–Rosen (EPR) correlations. This is in line with my defence in the past of the applicability of the Principle of Common Cause to quantum mechanics. I first review a contrary claim by Dan Hausman and Jim Woodward, who endeavour to preserve the CMC against a possible counterexample by asserting that the conditions for the application of the CMC are not met in the EPR experiment. In their (...) view the CMC is inapplicable to the EPR correlations—i.e. it neither obtains nor fails. The view is grounded upon the non-separability of the quantum state, and the consequent unavailability of interventions. I urge that whether interventions are available in EPR—and why—is a complex and contextual question that does not have a unique or uniform answer. Instead, I argue that different combinations of causal hypotheses under test and interpretations of quantum mechanics yield different answers to the question. (shrink)

To consider metaphysical claims a priori and devoid of empirical content, is a rather commonplace received opinion. This paper attempts an exploration of a contemporary philosophical heresy: it is possible to test metaphysical claims if they play an indispensable role in producing empirical success, i.e. novel predictions. To do so one, firstly, needs to express the metaphysical claims employed in the logico-mathematical language of a scientific theory, i.e. to explicate them. Secondly, one should have an understanding of what it is (...) to test and to verify or to falsify a metaphysical claim. Finally, one also need to consider the philosophical practice of testing a metaphysical claim. These three aspects are introduced in this paper and they are illustrated by means of the metaphysical concept of common cause and the principle of the common cause. (shrink)

The fact that there exist in nature thoroughly deterministic systems whose future behavior cannot be predicted, no matter how advanced or fined-tune our cognitive and technical abilities turn out to be, has been well established over the last decades or so, essentially in the light of two different theoretical frameworks, namely chaos theory and (some deterministic interpretation of) quantum mechanics. The prime objective of this paper is to show that there actually exists an alternative strategy to ground the divorce between (...) determinism and predictability, a way that is older than—and conceptually independent from—chaos theory and quantum mechanics, and which has not received much attention in the recent philosophical literature about determinism. This forgotten strategy—embedded in the doctrine called “emergent evolutionism”—is nonetheless far from being a mere historical curiosity that should only draw the attention of philosophers out of their concern for comprehensiveness. It has been indeed recently revived in the works of respected scientists. (shrink)

Van Fraassen's 1991 modal interpretation of Quantum Mechanics offers accounts of measurement and state preparation. I argue that both accounts overlook a class of interactions I call General Unitary Measurements, or GUMs. Ironically, GUMs are significant for van Fraassen's account of measurement because they challenge it, and significant for his account of preparation because they simplify it. Van Fraassen's oversight prompts a question about modal interpretations: developed to account for ideal measurement outcomes, can they consistently account as well for the (...) whole horizon of laboratory practices by which we investigate QM? (shrink)

Popper wrote extensively on the quantum theory. In Logic der Forschung he devoted a whole chapter to the topic, while the whole of Volume 3 of the Postscript to the Logic of Scientific Discovery is devoted to the quantum theory. This volume entitled Quantum Theory and the Schism in Physics incorporated a famous earlier essay, ‘Quantum Mechanics without “the Observer”’ . In addition Popper's development of the propensity interpretation of probability was much influenced by his views on the role of (...) probability in quantum theory, and he also wrote an insightful critique of the 1936 paper of Birkhoff and von Neumann on nondistributive quantum logic. (shrink)

In what sense do the sciences explain? Or do they merely describe what is going on without answering why-questions at all. But cannot description at an appropriate ‘level’ provide all that we can reasonably ask of an explanation? Well, what do we mean by explanation anyway? What, if anything, gets left out when we provide a so-called scientific explanation? Are there limits of explanation in general, and scientific explanation, in particular? What are the criteria for a good explanation? Is it (...) possible to satisfy all the desiderata simultaneously? If not, which should we regard as paramount? What is the connection between explanation and prediction? What exactly is it that statistical explanations explain? These are some of the questions that have generated a very extensive literature in the philosophy of science. In attempting to answer them, definite views will have to be taken on related matters, such as physical laws, causality, reduction, and questions of evidence and confirmation, of theory and observation, realism versus antirealism, and the objectivity and rationality of science. I will state my own views on these matters, in the course of this essay. To argue for everything in detail and to do justice to all the alternative views, would fill a book, perhaps several books. I want to lead up fairly quickly to modern physics, and review the explanatory situation there in rather more detail. (shrink)

In this essay we show that some thesis -contended by some authors searching on physical causation- about causal pseudoprocesses, processes of which the most salient aspect seems to be travelling faster than the speed of light, must be rejected o seriously modified. Secondly, we will argue that there is just one non causal entities category and that special relativity does not provide any particular motivation to appeal to an ontological distinction based on identity over time. In addition, this conclusion we (...) will enable us to offer a more accurate definition of a pseudoprocess than that found in the relevant literature. In third place, we will show in some detail how such processes, understood the way that we suggest here, are and have been valuable methodological tools when studying –through usual measurement procedures- effective causal relations holding in the physical world. Finally, we will connect our conclusions with R. Torretti’s criticism on the relation between ordinary causation and governed-by-differential-equations physical processes and we will show that, although neutral on his anthropocentric background, the account here argued provides, against what Torretti claims, a natural explanation to the physical connection between ordinary causation and causal processes such as studied by physics. (shrink)

It continues to be alleged that superluminal in uences of any sort would be inconsistent with special relativity for the following three reasons: they would imply the existence of a ‘distinguished’ frame; they would allow the detection of absolute motion; and they would violate the relativity of simultaneity. This paper shows that the first two objections rest upon very elementary misunderstandings of Minkowski geometry and on lingering Newtonian intuitions about instantaneity. The third objection has a basis, but rather than invalidating (...) the notion of faster-than-light influences it points the way to more general conceptions of simultaneity that could allow for quantum nonlocality in a natural way. (shrink)

I present a thought experiment in quantum mechanics and tease out some of its implications for the doctrine of “peaceful coexistence”, which, following Shimony, I take to be the proposition that quantum mechanics does not force us to revise or abandon the relativistic picture of causality. I criticize the standard arguments in favour of peaceful coexistence on the grounds that they are question-begging, and suggest that the breakdown of Lorentz-invariant relativity as a principle theory would be a natural development, given (...) the general trend of physics in this century. (shrink)

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)

This essay examines some of the arguments in David Deutsch's book The Fabric of Reality , chief among them its case for the so-called many-universe interpretation of quantum mechanics (QM), presented as the only physically and logically consistent solution to the QM paradoxes of wave/particle dualism, remote simultaneous interaction, the observer-induced 'collapse of the wave-packet', etc. The hypothesis assumes that all possible outcomes are realized in every such momentary 'collapse', since the observer splits off into so many parallel, coexisting, but (...) epistemically non-interaccessible 'worlds' whose subsequent branchings constitute the lifeline-or experiential world-series- for each of those proliferating centres of consciousness. Although Deutsch concedes that his 'multiverse' theory is counter-intuitive, he none the less takes it to be borne out beyond question by the sheer observational/predictive success of QM and the conceptual dilemmas that supposedly arise with alternative (single-universe) accounts. Moreover, he claims the theory resolves a range of longstanding philosophical problems, notably those of mind/body dualism, the various traditional paradoxes of time, and the freewill/determinism issue. The essay suggests on the contrary, that Deutsch unwittingly transposes into the framework of presentday quantum debate speculative themes from the history of rationalist metaphysics, often with bizarre or philosophically dubious results, and that he rules out at least one promising rival account, namely Bohm's 'hidden variables' theory. It goes on to consider reasons for resistance to that theory among proponents of the 'orthodox' (Copenhagen) doctrine, and for the strong anti-realist, at times even irrationalist bias that has characterized much of this discussion since Bohr's debates with Einstein about quantum non-locality, observer-intervention, and the limits of precise measurement. Finally, the contrast is pointed out between Deutsch's ontologically extravagant use of the many-worlds hypothesis (akin to certain ideas advanced by speculative metaphysicians from Leibniz down) and those realist modes of counterfactual reasoning- e.g. in Kripke and the early Putnam- which deploy similar arguments to very different causal-explanatory ends. (shrink)

In this essay, I offer a critical evaluation of Hilary Putnam's writings on epistemology and philosophy of science, in particular his engagement with interpretative problems in quantum mechanics. I trace the development of his thinking from the late 1960s when he adopted a strong causal-realist position on issues of meaning, reference, and truth, via the "internal realist" approach of his middle-period writings, to the various forms of pragmatist, naturalized, or "commonsense" epistemology proposed in his latest books. My contention is that (...) Putnam's retreat from a full-fledged realist outlook has been prompted in large part by his belief that it cannot possibly be reconciled with the implications of quantum mechanics for our understanding of processes and events in the subatomic domain. However, I suggest, this response should be seen as premature given the range of as-yet unresolved problems with quantum mechanics on the orthodox (Copenhagen) interpretation and also the existence of an alternative account - David Bohm's hidden-variables theory - which perfectly matches the established predictive-observational results while providing a credible realist ontology. I also examine Putnam's case for adopting a nonstandard (three-valued) "quantum logic" in relation to the thinking of other philosophers - Michael Dummett among them - who have espoused a more global or doctrinaire version of anti-realism. I conclude that Putnam's early (causal-realist) position is by no means untenable in light of the various arguments that he now takes as counting decisively against it. (shrink)