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 (...) class='Hi'>argument does not need 'counterfactual definiteness'. (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 (...) class='Hi'>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)

I present a very general and simple argument—based on the no-signalling theorem—showing that within the framework of the unitary Schrödinger equation it is impossible to reproduce the phenomenological description of quantum mechanical measurements (in particular the collapse of the state of the measured system) by assuming a suitable mixed initial state of the apparatus. The thrust of the argument is thus similar to that of the ‘insolubility theorems’ for the measurement problem of quantum mechanics (which, however, focus on (...) the impossibility of reproducing the macroscopic measurement results). Although I believe this form of the argument is new, I argue it is essentially a variant of Einstein’s reasoning in the context of the EPR paradox—which is thereby illuminated from a new angle. (shrink)

We reconsider the nonlocal aspects of quantum mechanics with special reference to the EPR argument. We first confine our considerations to the correlations between the outcomes of measurements on spatially distant constituents, without worrying about the measurement problem. We pay particular attention to the relativistic aspects of the problem. Our first conclusion is that, when developed along the lines we follow, the EPR inference that quantum correlations and locality together imply incompleteness, is appropriate. We then investigate whether the other (...) common conclusion from the EPR argument, i.e. that standard quantum theory implies a spooky action at a distance, is correct. We emphasize the crucial role played by the locality assumption and we discuss the use of counterfactuals in the ‘relativistic’ reformulation of the EPR argument. We show that the above conclusion is false if understood as saying that standard quantum theory exhibits, at least with reference to possessed elements of physical reality, some sort of parameter dependence. Thus, in a sense, the coexistence of quantum mechanics with relativity is even more peaceful than commonly thought. We then go through a similar analysis by taking explicitly into account the measurement process. We point out the difficulties which one meets when confronting reduction mechanisms with relativistic requirements. This leads us to recognize the necessity of reconsidering the criteria for attributing objective properties to individual physical systems. Our final conclusion is that, in principle, it is perfectly possible to build up theories leading to the objectification of macroscopic properties which do not imply any spooky action at a distance. (shrink)

This paper tries to reconstruct Ernst Cassirer's potential reception of the EPR argument, as exposed by Einstein in his letter to Cassirer of March 1937. It is shown that, in conformity with his transcendental epistemology taking the conditions of accessibility as constitutive of the quantum object, Cassirer would probably have rejected the argument. Indeed, Cassirer would probably not have subscribed to its separability/local causality presupposition (which goes against his interpretation of the quantum formalism as a self-suf!cient condition constitutive (...) of the quantum object, without any reliance on spatial intuition), nor to its completeness requirement (as his partial endorsement of Bohr's complementarity, and his rejection of the Kantian "idea of complete determination", illustrate). By rejecting both of its premises, Cassirer's philosophy of physics thus enables to escape the EPR dilemma, and exhibits what, in Kantian terms, might be called a "negative utility" with respect to physical science. A further investigation of the anti-reductionist utility of Cassirer's systematic philosophy with respect to physics and other "symbolic forms" is !nally suggested. (shrink)

We perform a frequency analysis of the EPR-Bell argumentation. One of the main consequences of our investigation is that the existence of probability distributions of the Kolmogorov-type which was supposed by some authors is a mathematical assumption which may not be supported by actual physical quantum processes. In fact, frequencies for hidden variables for quantum particles and measurement devices may fluctuate from run to run of an experiment. These fluctuations of frequencies for micro-parameters need not contradict to the stabilization of (...) frequencies for physical observables. If, nevertheless, micro-parameters are also statistically stable, then violations of Bell's inequality and its generalizations may be a consequence of dependence of collectives corresponding to two different measurement devices. Such a dependence implies the violation of the factorization rule for the simultaneous probability distribution. Formally this rule coincides with the well known BCHS locality condition (or outcome independence condition). However, the frequency approach implies totally different interpretation of dependence. It is not dependence of events, but it is dependence of collectives. Such a dependence may be induced by the same preparation procedure. (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.

Two EPR arguments are reviewed, for their own sake, and for the purpose of clarifying the status of "stochastic" hidden variables. The first is a streamlined version of the EPR argument for the incompleteness of quantum mechanics. The role of an anti-instrumentalist ("realist") interpretation of certain probability statements is emphasized. The second traces out one horn of a central foundational dilemma, the collapse dilemma; complex modal reasoning, similar to the original EPR, is used to derive determinateness (of all spin (...) components of two spin- 1 / 2 particles in the singlet state) from just (a form of) weak locality, result definiteness, and an assumption on propensities based on conservation. Theories meeting these conditions are therefore constrained by the Bell inequalities. Neither controversial assumptions of "strong locality" ("factorability") nor of determinism are employed in the derivation. The categories of "stochastic hidden variables" are then analyzed; one can focus on "quasi-definite" theories, without loss of generality. A means of excluding these is proposed, based on a demand that certain ideal cases be accurately treated. Theorems from quantum measurement theory, sometimes cited as showing that such cases are not physically possible, are found inapplicable. (shrink)

We give a conceptually simple proof of nonlocality using only the perfect correlations between results of measurements on distant systems discussed by Einstein, Podolsky and Rosen—correlations that EPR thought proved the incompleteness of quantum mechanics. Our argument relies on an extension of EPR by Schrödinger. We also briefly discuss nonlocality and “hidden variables” within Bohmian mechanics.

Bohr’s reply to Einstein, Podolsky, and Rosen’s argument for the incompleteness of quantum theory is notoriously difficult to unravel. It is so diffcult, in fact, that over 60 years later, there remains important work to be done understanding it. Work by Fine , Beller and Fine , and Beller goes a long way towards correcting earlier misunderstandings of Bohr’s reply. This essay is intended as a contribution to the program of getting to the truth of the matter, both historically (...) and philosophically. In a paper of this length, a full account of Bohr’s reply is impossible, and so I shall focus on one issue where it seems further clarification is required, namely, Bohr’s attempt to illustrate EPR’s argument by means of a thought experiment. In addition, I shall attempt to clarify a few other points which, however minor, have apparently contributed to misunderstandings of Bohr’s position. As the title of this paper suggests, an account of these few points does not constitute an account of Bohr’s reply, but it is an important step in that direction. (shrink)

For many years after Bohr's response to the EPR argument, Bohr was considered to have provided an authoritative rebuttal of the ideas of the paper, and more generally of Einstein's stance on quantum theory. More recently, however, there has been great difficulty even in achieving general agreement on Bohr's meaning. Two recent papers, by Dickson, and by Clifton and Halvorson, have sought to establish the structure of Bohr's argument. In the present paper, the papers of EPR and Bohr (...) are re-assessed in the light of these recent papers, and also in light of the development and presentation of quantum information theory. (shrink)

Recent studies have shown that Einstein did not write the EPR paper and that he was disappointed with the outcome. He thought, rightly, that his own argument for the incompleteness of quantum theory was badly presented in the paper. We reconstruct the argument of EPR, indicate the reasons Einstein was dissatisfied with it, and discuss Einstein's own argument. We show that many commentators have been misled by the obscurity of EPR into proposing interpretations of its argument (...) that do not accurately represent Einstein's own views. Finally, we evaluate Einstein's own incompleteness argument, concluding that recent experimental findings have likely shown it to be unsound. (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)

"Indeed I have very little idea of what this means. I do not understand in what sense the word `mechanical' is used, in characterizing the disturbances that Bohr does not contemplate, as distinct from those he does. I do not know what the italicized passage means--- `an influence on the very conditions...' . Could it mean just that different experiments on the first system give different kinds of information about the second? But this was one of the main points of (...) EPR, who observed that one could learn *either* the position *or* the momentum of the second system..... Is Bohr just rejecting the premise--- `no action at a distance'---rather than refuting the argument?". (shrink)

The best case for thinking that quantum mechanics is nonlocal rests on Bell's Theorem, and later results of the same kind. However, the correlations characteristic of Einstein–Podolsky–Rosen (EPR)–Bell (EPRB) experiments also arise in familiar cases elsewhere in quantum mechanics (QM), where the two measurements involved are timelike rather than spacelike separated; and in which the correlations are usually assumed to have a local causal explanation, requiring no action-at-a-distance (AAD). It is interesting to ask how this is possible, in the light (...) of Bell's Theorem. We investigate this question, and present two options. Either (i) the new cases are nonlocal too, in which case AAD is more widespread in QM than has previously been appreciated (and does not depend on entanglement, as usually construed); or (ii) the means of avoiding AAD in the new cases extends in a natural way to EPRB, removing AAD in these cases too. There is a third option, viz., that the new cases are strongly disanalogous to EPRB. But this option requires an argument, so far missing, that the physical world breaks the symmetries which otherwise support the analogy. In the absence of such an argument, the orthodox combination of views—action-at-a-distance in EPRB, but local causality in its timelike analogue—is less well established than it is usually assumed to be. 1 Introduction1.1 Background1.2 Outline of the argument2 The Experiments2.1 Standard EPRB2.2 Sideways EPRB2.3 Comparing the experiments2.4 The need for beables3 The Symmetry Considerations3.1 The action symmetry3.2 Time-symmetry in SEPRB4 The Basic Trilemma4.1 An intuitive defence of Option III?5 Avoiding the Trilemma?6 The Classical Objection7 Defending Option III7.1 The free will argument7.2 Independence and consistency8 Entanglement and Epistemic Perspective. (shrink)

We prove that the general scheme for physical theories that we have called semantic realism(SR) in some previous papers copes successfully with a number of EPR-like paradoxes when applied to quantum physics (QP). In particular, we consider the old arguments by Furry and Bohm- Aharonov and show that they are not valid within a SR framework. Moreover, we consider the Bell-Kochen-Specker und the Bell theorems that should prove that QP is inherently contextual and nonlocal, respectively, and show that they can (...) be invalidated in the SR approach. This removes the seeming contradiction between the basic assumptions of SR and QP, and proves that some problematic features that are usually attributed to QP, us contextuality and nonlocality, occur because of the adoption of a verificationist position, from one side, and from an insufficient adherence to the operational principles that have inspired QP itself, from the other side. (shrink)

We present an exegesis of the Einstein-Podolsky-Rosen argument for the incompleteness of quantum mechanics, and defend it against the critique in Fine. (1) We contend,contra Fine, that it compares favorably with an argument reconstructed by him from a letter by Einstein to Schrödinger; and also with one given by Einstein in a letter to Popper. All three arguments turn on a dubious assumption of “separability,” which accords separate elements of reality to space-like separated systems. We discuss how this (...) assumption figures in the literature spawned by the Bell inequalities. (shrink)

Using three intuitive notions about causes, including Redhead's robustness condition, I formulate necessary conditions on partial causes. I then demonstrate that we cannot explain the EPR correlations in terms of partial causes unless we abandon the quantum mechanical framework and adopt a nonlocal hidden-variable theory. The argument, unlike its predecessors, does not appeal to relativity theory.

We examine possible causal structures of experiments with entangled quantum objects. Previously, these structures have been obscured by assuming a misleading probabilistic analysis of quantum non locality as 'Outcome Dependence or Parameter Dependence' and by directly associating these correlations with influences. Here we try to overcome these shortcomings: we proceed from a recent stronger Bell argument, which provides an appropriate probabilistic description, and apply the rigorous methods of causal graph theory. Against the standard view that there is only an (...) influence between the measurement outcomes, we show that there must be an influence from one setting to its distant outcome: EPR correlations can only come about if one of the outcomes is a common effect of both settings. Our discussion makes explicit under which assumptions similar conclusions from information theoretic considerations can be interpreted causally. (shrink)

Although Bohr's reply to the EPR argument is supposed to be a watershed moment in the development of his philosophy of quantum theory, it is difficult to find a clear statement of the reply's philosophical point. Moreover, some have claimed that the point is simply that Bohr is a radical positivist. In this paper, we show that such claims are unfounded. In particular, we give a mathematically rigorous reconstruction of Bohr's reply to the _original_ EPR argument that clarifies (...) its logical structure, and which shows that it does not rest on questionable philosophical assumptions. Rather, Bohr's reply is dictated by his commitment to provide "classical" and "objective" descriptions of experimental phenomena. (shrink)

In his recent work, Michael Redhead (1986, 1987, 1989, 1990) has introduced a condition he calls robustness which, he argues, a relation must satisfy in order to be causal. He has used this condition to argue further that EPR-type correlations are neither the result of a direct causal connection between the correlated events, nor the result of a common cause associated with the source of the particle pairs which feature in these events. Andrew Elby (1992) has used this same condition (...) as a premise in an independent argument for the conclusion that EPR-type correlations cannot be causally explained (except, perhaps, by a nonlocal hidden variable theory). I wish to argue here that robustness is itself too fragile a notion to support such conclusions. (shrink)

The argument of Einstein, Podolsky, and Rosen is reviewed with attention to logical structure and character of assumptions. Bohr's reply is discussed. Bell's contribution is formulated without use of hidden variables, and efforts to equate hidden variables to realism are critically examined. An alternative derivation of nonlocality that makes no use of hidden variables, microrealism, counterfactual definiteness, or any other assumption alien to orthodox quantum thinking is described in detail, with particular attention to the quartet or broken-square question.

The Einstein-Podolsky-Rosen argument for the incompleteness of quantum mechanics involves two assumptions: one about locality and the other about when it is legitimate to infer the existence of an element-of-reality. Using one simple thought experiment, we argue that quantum predictions and the relativity of simultaneity require that both these assumptions fail, whether or not quantum mechanics is complete.

Entangled states are a specific feature of quantum physics that neither have a counterpart in classical physics nor in the realm of our ordinary experiences. In this chapter we outline the debate about these particular states both historically and systematically. We delineate how the debate originated in an argument for the incompleteness of quantum mechanics by Einstein, Podolsky and Rosen, and we show why, on the one hand, the argument is not considered convincing today, on the other hand, (...) however, still affects present discussions. In a second part we give a systematic overview over the contemporary debate on entanglement which focusses on Bell’s theorem and its consequences. Discerning different levels, we reconstruct the theorem and its premises in a clear way and discuss possible consequences. We analyze in detail the received view that Bell’s theorem implies non-locality and relate it to concepts such as “non-separability‘ and “holism‘. Especially we examine the question whether the phenomena involving entangled systems can be explained causally and whether the central conflict between a non-locality and the theory of relativity can be solved. (shrink)

We argue that causal decision theory is no worse off than evidential decision theory in handling entanglement, regardless of one’s preferred interpretation of quantum mechanics. In recent works, Ahmed and Ahmed and Caulton : 4315–4352, 2014) have claimed the opposite; we argue that they are mistaken. Bell-type experiments are not instances of Newcomb problems, so CDT and EDT do not diverge in their recommendations. We highlight the fact that a Causal Decision Theorist should take all lawlike correlations into account, including (...) potentially acausal entanglement correlations. This paper also provides a brief introduction to CDT with a motivating “small” Newcomb problem. The main point of our argument is that quantum theory does not provide grounds for favouring EDT over CDT. (shrink)

We argue that causal decision theory is no worse off than evidential decision theory in handling entanglement, regardless of one’s preferred interpretation of quantum mechanics. In recent works, Ahmed and Ahmed and Caulton : 4315–4352, 2014) have claimed the opposite; we argue that they are mistaken. Bell-type experiments are not instances of Newcomb problems, so CDT and EDT do not diverge in their recommendations. We highlight the fact that a Causal Decision Theorist should take all lawlike correlations into account, including (...) potentially acausal entanglement correlations. This paper also provides a brief introduction to CDT with a motivating “small” Newcomb problem. The main point of our argument is that quantum theory does not provide grounds for favouring EDT over CDT. (shrink)

We argue against the common view that it is impossible to give a causal account of the distant correlations that are revealed in EPR-type experiments. We take a realistic attitude about quantum mechanics which implies a willingness to modify our familiar concepts according to its teachings. We object to the argument that the violation of factorizability in EPR rules out causal accounts, since such an argument is at best based on the desire to retain a classical description of (...) nature that consists of processes that are continuous in space and time. We also do not think special relativity prohibits the superluminal propagation of causes in EPR, for the phenomenon of quantum measurement may very well fall outside the domain of application of special relativity. It is possible to give causal accounts of EPR as long as we are willing to take quantum mechanics seriously, and we offer two such accounts. (shrink)

Verschränkte Zustände sind einer der charakteristischen Züge der Quantenphysik, für die es weder eine Entsprechung in der klassischen Physik noch in der alltäglichen Erfahrungswelt gibt. In diesem Kapitel umreißen wir historisch und systematisch die Debatte um diese besonderen Zustände. Wir stellen ihren Ursprung in einem Argument von Einstein, Podolsky und Rosen für die Unvollständigkeit der Quantenmechanik dar und zeigen, warum dieses Argument einerseits heute nicht mehr als überzeugend betrachtet wird, andererseits dennoch bis in aktuelle Debatten hinein nachwirkt. In (...) einem zweiten Teil geben wir einen systematischen überblick über die zeitgenössischen Debatten zu Verschränkung, die sich um Bells Theorem und dessen Konsequenzen drehen. Einer klaren Darstellung des Theorems und seiner Voraussetzungen auf verschiedenen Ebenen folgt eine Diskussion der möglichen Konsequenzen. Detailliert wird die meist angeführte Konsequenz einer Nicht-Lokalität analysiert und in Beziehung zu Begriffen wie?Nicht-Separabilität“ und?Holismus“ gesetzt. Besonderes Augenmerk liegt auf der Frage, ob die Phänomene verschränkter Zustände kausal erklärt werden können und ob der zentrale Konflikt einer Nicht-Lokalität mit der Relativitätstheorie gelöst werden kann. (shrink)

Verschränkte Zustände sind einer der charakteristischen Züge der Quantenphysik, für die es weder eine Entsprechung in der klassischen Physik noch in unserer alltäglichen Erfahrungswelt gibt. In diesem Kapitel umreißen wir historisch und systematisch die Debatte um diese besonderen Zustände. Wir stellen ihren Ursprung in einem Argument von Einstein, Podolsky und Rosen für die Unvollständigkeit der Quantenmechanik dar und zeigen, warum dieses Argument einerseits heute nicht mehr als überzeugend betrachtet wird, andererseits dennoch bis in aktuelle Debatten hinein nachwirkt. In (...) einem zweiten Teil geben wir einen systematischen Überblick über die zeitgenössischen Debatten zu Verschränkung, die sich um Bells Theorem und dessen Konsequenzen drehen. Einer klaren Darstellung des Theorems und seiner Voraussetzungen auf verschiedenen Ebenen folgt eine Diskussion der möglichen Konsequenzen. Detailliert wird die meist angeführte Konsequenz einer Nicht-Lokalität analysiert und in Beziehung zu Begriffen wie „Nicht-Separabilität“ und „Holismus“ gesetzt. Besonderes Augenmerk liegt auf der Frage, ob die Phänomene verschränkter Zustände kausal erklärt werden können und ob der zentrale Konflikt einer Nicht-Lokalität mit der Relativitätstheorie gelöst werden kann. (shrink)

Taking a cue from Bohr’s use of the notion of a reference frame in his reply to EPR’s argument against the completeness (and consistency) of standard quantum theory, this paper presents an analysis ofthe role of reference frames in the situation considered by EPR, using a quantum‐theoretical account of physical reference frames based on the work of Mackey, and Aharonov and Kaufherr. That analysis appears to justify at least some crucial aspects of a Bohrian reply to EPR.

It is often argued that no local common cause models of EPR correlation exist. However, Szabó and Rédei pointed out that such arguments have the tacit assumption that plural correlations have the same common causes. Furthermore, Szabó showed that for EPR correlation a local common cause model in his sense exists. One of his requirements is that common cause events are statistically independent of apparatus settings on each side. However, as Szabó knows, to meet this requirement does not entail that (...) different combinations of common cause events (e.g. meet and join in lattice-theoretic terminology) are statistically independent of measurement settings. This further condition is formulated in two ways. First, the apparatus settings are completely independent of such combinations. Second, the apparatus settings on each side are independent of such combinations. Does a common cause model which meets the former and the latter respectively exist? This problem is considered. In particular, the latter version is Szabó’s and Rédei’s open problem. Negative answers are given to both versions. (shrink)

Some influential arguments in the metaphysics of consciousness, in particular Chalmers’ Zombie Argument, suppose that all the physical properties of composed physical systems are metaphysically necessitated by their fundamental constituents. In this paper I argue against this thesis in order to debate Chalmers’ argument. By discussing, in non-technical terms, an EPR system I try to show that there are good reasons to hold that some composed physical systems have properties which are nomologically necessitated by their fundamental constituents, i.e., (...) which emerge in the sense of the so-called ‘nomological supervenience’ views. (shrink)

Specker contradiction, I prove that ‘local realistic’ theories predict nontrivial violations of the quantum mechanical EPR-type perfect anticorrelations. The proof invokes the same stochastic local realism conditions used in Bell arguments. For a class of theories called ‘orthodox spin theories’, the perfect anticorrelations used in the proof emerge from rotational symmetry. Therefore, an orthodox spin theorist must abandon either the spirit of relativity, as encoded by local realism, or the letter of relativity, which demands rotational invariance.

The concept of “propagation in time” of Vigier and co-workers (V et al.) implies the idea of a supertime; it is thus alien to most Minkowskian pictures and certainly to mine. From this stems much of Vet al.'s misunderstandings of my position. In steady motion of a classical fluid nobody thinks that “momentum conservation is violated,” or that “momentum is shot upstream without cause” because of the suction from the sinks! Similarly with momentum-energy in space-time and the acceptance of an (...) advanced causality. As for the CT invariance of the Feynman propagator, the causality asymmetry it entails is factlike, not lawlike. The geometrical counterpart of the symmetry between prediction and retrodiction and between retarded and advanced waves, as expressed in the alternative expressions 〈B|UA〉=〈BU|A〉=〈B|U|A〉 for a transition amplitude between a preparation |A〉 and a measurement |B〉, is CPT-invariant, not PT-invariant. These three expressions respectively illustrate the collapse, the retrocollapse, and the symmetric collapse-and-retrocollapse concepts. As for Sutherland's argument, what it “falsifies” is not my retrocausation concept but the hidden-variables assumption he has unwittingly made. (shrink)

A formulation by Einstein of the Einstein-Podolsky-Rosen incompleteness argument found in his scientific manuscripts is presented and briefly commented on. It is the only known version in which Einstein discussed the argument for spin observables. The manuscript dates, in all probability, from late 1954 or early 1955 and hence also represents Einstein's latest version of the incompleteness argument and one of his last statements on quantum theory in general. A puzzling formulation raises the question of Einstein's interpretation (...) of space quantization and the non-classical spin degree of freedom. (shrink)

Skyrms's formulation of the argument against stochastic hidden variables in quantum mechanics using conditionals with chance consequences suffers from an ambiguity in its "conservation" assumption. The strong version, which Skyrms needs, packs in a "no-rapport" assumption in addition to the weaker statement of the "experimental facts." On the positive side, I argue that Skyrms's proof has two unnoted virtues (not shared by previous proofs): (1) it shows that certain difficulties that arise for deterministic hidden variable theories that exploit a (...) nonclassical probability theory extend to the stochastic case; (2) the use of counterfactual conditionals relates the Bell puzzle to Dummett's (1976) discussion of realism in quantum mechanics. (shrink)

From conceptual point of view, we argue about the nature of reality inferred from EPR argument in quantum mechanics.

In the May 15, 1935 issue of Physical Review Albert Einstein co-authored a paper with his two postdoctoral research associates at the Institute for Advanced Study, Boris Podolsky and Nathan Rosen. The article was entitled “Can Quantum Mechanical Description of Physical Reality Be Considered Complete?” (Einstein et al. 1935). Generally referred to as “EPR”, this paper quickly became a centerpiece in the debate over the interpretation of the quantum theory, a debate that continues today. The paper features a striking case (...) where two quantum systems interact in such a way as to link both their spatial coordinates in a certain direction and also their linear momenta (in the same direction). As a result of this “entanglement”, determining either position or momentum for one system would fix (respectively) the position or the momentum of the other. EPR use this case to argue that one cannot maintain both an intuitive condition of local action and the completeness of the quantum description by means of the wave function. This entry describes the argument of that 1935 paper, considers several different versions and reactions, and explores the ongoing significance of the issues they raise. (shrink)

We present the possibility of a relativistic formulation of the Einstein-Podolsky-Rosen argument. We pay particular attention to the need for a reformulation of the so-called reality criterion. We introduce such a reformulation for the reality criterion due to Ghirardi and Grassi and show how it applies to the nonrelativistic EPR argument. We elaborate on Ghiradi and Grassi’s proof and explain why it cannot be circumvented. Finally, we review and summarise our own views. This is a continuation of the (...) paper by myself and Patrick La Riviere whose defects are exposed in the present work. (shrink)

Cet ouvrage pose la question de la construction de sens au cours de religion catholique de Belgique francophone, avec une proposition qui concerne plus particulièrement les élèves de la fin du secondaire et leurs enseignant·es. Trois fils rouges guident le travail, qui lui confèrent une coloration spécifique. Le premier a trait au sens, entendu dans son acception la plus large, qui va du sens du langage au sens le plus ultime, en passant par le sens tel qu'il se décline au (...) coeur d’une existence. Le suivant renvoie à l’articulation entre la construction et la transmission d’un sens, la première expression se rapportant à la pratique des communautés de recherche, la seconde s’inscrivant dans l’acception classique du terme en lien aux savoirs. Le dernier fil conducteur est relatif à l’association de deux disciplines essentielles pour le cours: la philosophie et la théologie, avec une insistance sur la philosophie comme mode de vie et quête de sagesse, à rapprocher de la quête de sens, mais également sur l’intérêt d’introduire les jeunes à une forme de silence et d’introspection. (shrink)

In my reconstruction of Bohr's reply to the Einstein-Podolsky-Rosen argument, I pointed out that Bohr showed explicitly, within the framework of the complementarity interpretation, how a locally maximal measurement on a subsystem S2 of a composite system S1+S2, consisting of two spatially separated subsystems, can make determinate both a locally maximal Boolean subalgebra for S2 and a locally maximal Boolean subalgebra for S1. As it stands, this response is open to an objection. In this note, I show that meeting (...) the objection requires a modification of the complementarity thesis concerning what propositions can be taken as determinate, or what observables can be raken to have values, in a given measurement context. (shrink)

It is widely accepted that the violation of Bell inequalities excludes local theories of the quantum realm. This paper presents a stronger Bell argument which even forbids certain non-local theories. The conclusion of the stronger Bell argument presented here provably is the strongest possible consequence from the violation of Bell inequalities on a qualitative probabilistic level. Since among the excluded non-local theories are those whose only non-local probabilistic connection is a dependence between the space-like separated measurement outcomes of (...) EPR/B experiments, outcome dependence cannot be the crucial dependence for explaining a violation of Bell inequalities. Rather, the remaining non-local theories, which can violate Bell inequalities, are characterized by the fact that at least one of the measurement outcomes in some sense probabilistically depends both on its local as well as on its distant measurement setting. While this is not to say that what is usually called parameter dependence has to hold, some kind of dependence on the distant parameter cannot be avoided. Against the received view, established by Jarrett and Shimony, that on a probabilistic level quantum non-locality amounts to outcome dependence, this result confirms and makes precise Maudlin's claim that some kind of parameter dependence is required. (shrink)

It is argued that formal reconstructions of the EPR-argument do not only show semantical incompleteness, but also incorrectness of quantum mechanics together with the projection postulate. The latter has to be rejected because it contradicts Schrödinger's equation. A logical analogon to the problem is given.

In 1935, Einstein, Podolsky, and Rosen (EPR) published an important paper in which they claimed that the whole formalism of quantum mechanics together with what they called a “Reality Criterion” imply that quantum mechanics cannot be complete. That is, there must exist some elements of reality that are not described by quantum mechanics. They concluded that there must be a more complete description of physical reality involving some hidden variables that can characterize the state of affairs in the world in (...) more detail than the quantum mechanical state. This conclusion leads to paradoxical results. -/- As Bell proved in 1964, under some further but quite plausible assumptions, this conclusion that there are hidden variables implies that, in some spin-correlation experiments, the measured quantum mechanical probabilities should satisfy particular inequalities (Bell-type inequalities). The paradox consists in the fact that quantum probabilities do not satisfy these inequalities. And this paradoxical fact has been confirmed by several laboratory experiments since the 1970s. -/- Some researchers have interpreted this result as showing that quantum mechanics is telling us nature is non-local, that is, that particles can affect each other across great distances in a time too brief for the effect to have been due to ordinary causal interaction. Others object to this interpretation, and the problem is still open and hotly debated among both physicists and philosophers. It has motivated a wide range of research from the most fundamental quantum mechanical experiments through foundations of probability theory to the theory of stochastic causality as well as the metaphysics of free will. (shrink)

In 1935, Einstein, Podolsky, and Rosen (EPR) published an important paper in which they claimed that the whole formalism of quantum mechanics together with what they called a “Reality Criterion” imply that quantum mechanics cannot be complete. That is, there must exist some elements of reality that are not described by quantum mechanics. They concluded that there must be a more complete description of physical reality involving some hidden variables that can characterize the state of affairs in the world in (...) more detail than the quantum mechanical state. This conclusion leads to paradoxical results. -/- As Bell proved in 1964, under some further but quite plausible assumptions, this conclusion that there are hidden variables implies that, in some spin-correlation experiments, the measured quantum mechanical probabilities should satisfy particular inequalities (Bell-type inequalities). The paradox consists in the fact that quantum probabilities do not satisfy these inequalities. And this paradoxical fact has been confirmed by several laboratory experiments since the 1970s. -/- Some researchers have interpreted this result as showing that quantum mechanics is telling us nature is non-local, that is, that particles can affect each other across great distances in a time too brief for the effect to have been due to ordinary causal interaction. Others object to this interpretation, and the problem is still open and hotly debated among both physicists and philosophers. It has motivated a wide range of research from the most fundamental quantum mechanical experiments through foundations of probability theory to the theory of stochastic causality as well as the metaphysics of free will. (shrink)

This chapter contains sections titled: Causation, Counterfactuals, and Laws Two World Pictures The EPR Argument A Note on Wave Collapse But is it Causation? Superluminal Influences and Relativity.