Separating Einstein's separability

An important part of the influential Humean doctrine in philosophy is the supervenience principle (sometimes referred to as the principle of separability). This principle asserts that the complete state of the world supervenes on the intrinsic properties of its most fundamental components and their spatiotemporal relations (the so-called Humean mosaic). There are well-known arguments in the literature purporting to show that in quantum mechanics the Humean supervenience principle is violated, due to the existence of entangled states. Recently, however, arguments have been presented to the effect that the supervenience principle can be defended in Bohmian mechanics. The key element of this strategy lies in the observation that according to Bohmian mechanics the fundamental facts about particles are facts about their spatial locations, and moreover, for any proper subsystem of the world its state may non-trivially depend on the spatial configuration of the rest of the universe. Thus quantum-mechanical states of subsystems do not represent their intrinsic properties but rather characterize their relations with the environment. In this paper we point out the worry that this Bohmian strategy—known as Bohumianism—saves the letter but not the spirit of the Humean doctrine of supervenience, since it prima facie violates another seemingly important Humean principle, which we call Strong Supervenience and whose denial implies the existence of necessary connections among distinct individuals. We argue that the best defense for Bohumians is to question the fundamental existence of complex physical systems and their states by treating any reference to them as a convenient description of the underlying collection of Bohmian particles. We consider several pros and cons of this strategy.

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.

Quantum reality: theory and philosophy

In what follows, I examine three main points which may help us to understand the deep nature of Einstein's objections to quantum mechanics. After having played a fundamental pioneer role in the birth of quantum physics, Einstein was, as is well known, far less enthusiastic about its constitution as a quantum mechanics and, since 1927, he constantly argued against the pretention of its founders and proponents to have settled a definitive and complete theory. I emphasize first the importance of the philosophical climate, which was dominated by the Copenhagen orthodoxy and Bohr's idea of complementarity: What Einstein was primarily reluctant to was to accept the fundamental character of quantum mechanics as such, and to modify for it the basic principles of knowledge. I thus stress the main lines of Einstein's own programme in respect to quantum physics, which is to be considered in relation to his other contemporary attempts and achievements. Finally, I show how Einstein's arguments, when dealing with his objections, have been fruitful and some of them still worthy, with regard to recent developments concerning local nonseparability as well as concerning the problems of completeness and accomplishment of quantum theory.

In this Einstein Year of Physics it seems appropriate to look at an important aspect of Einstein's work that is often down-played: his contribution to the debate on the interpretation of quantum mechanics. Contrary to physics ‘folklore’, Bohr had no defence against Einstein's 1935 attack (the EPR paper) on the claimed completeness of orthodox quantum mechanics. I suggest that Einstein's argument, as stated most clearly in 1946, could justly be called Einstein's reality – locality – completeness theorem, since it proves that one of these three must be false. Einstein's instinct was that completeness of orthodox quantum mechanics was the falsehood, but he failed in his quest to find a more complete theory that respected reality and locality. Einstein's theorem, and possibly Einstein's failure, inspired John Bell in 1964 to prove his reality – locality theorem. This strengthened Einstein's theorem (but showed the futility of his quest) by demonstrating that either reality or locality is a falsehood. This revealed the full non-locality of the quantum world for the first time.

Heisenberg's observability principle

SUMMARY. — In this article, I examine Einstein's objections to quantum mechanics, with the formalism's interpretation in terms of complementarity as the historical setting. From 1924 to 1927, the period of development of a formalised quantum theory, Einstein raised certain questions that kept him from joining the throng of ardent supporters. Against the theory and its interpretation of 1927, he at first advanced arguments with the idea of eventually finding a flaw in quantum mechanics, and casting doubts upon its pretensions of completeness. Finally acknowledging, in 1931, the theory's coherence and accuracy at describing phenomena, he then tried to put forth objections to the theory's interpretation, which aimed at demonstrating the theory's incompleteness. These arguments culminated in the « Einstein-Podolsky-Rosen » article of 1935, and Einstein repeated them continually until his death. The analysis here calls, of course, for assessments of both the import of Einstein's arguments in relation to physics today, as well as to Einstein's own conceptions where theoretical physics is concerned, but these go beyond the aims of the present article.

Einstein made several attempts to argue for the incompleteness of quantum mechanics (QM), not all of them using a separation principle. One unpublished example, the box parable, has received increased attention in the recent literature. Though the example is tailor-made for applying a separation principle and Einstein indeed applies one, he begins his discussion without it. An analysis of this first part of the parable naturally leads to an argument for incompleteness not involving a separation principle. I discuss the argument and its systematic import. Though it should be kept in mind that the argument is not the one Einstein intends, I show how it suggests itself and leads to a conflict between QM’s completeness and a physical principle more fundamental than the separation principle, i.e. a principle saying that QM should deliver probabilities for physical systems possessing properties at definite times.

This essay pursues one historical and one conceptual task. The historical task is to reconstruct the “thinking-in-orders” tradition in political economy as a contextual approach to socio-economic reality, a tradition in which James Buchanan was socialized and to which he was a life-long contributor. The historical mainline extends from classical political economy to ordoliberalism, and shows how contextual economics has gained relevance in periods of transformation and transition. Living today in a world of fundamental transformation, the essay’s conceptual task is to depict how a recent research program, “New Economics of Order”, revitalizes the ordoliberal tradition by complementing it with Virginia School impulses of James Buchanan and Bloomington School impulses of Elinor and Vincent Ostrom. This new contextual research program conceptualizes the balance between the fragility stemming from the dynamics of globalization and digitalization, and the provision of statics through the state and civil society as demanded by the citizen.

Einstein's arguments concerning the interpretation of quantum mechanics are reviewed and contrasted with certain misconceptions regarding his attitude toward the theory. He considered Born's statistical interpretation to be the only satisfactory one, and he was not a supporter of hidden-variable theories such as that of Bohm. His criticism of the interpretation accepted, at least tacitly, by many physicists was that the quantum state function does not provide a description of an individual system but rather of an ensemble of similar systems. This criticism was not based merely upon his famous remark that God does not play dice, but upon some definite physical arguments which did not assume determinism.

It was observed in §1.4 that Einstein's method of criticizing the orthodox view of quantum theory was to focus on examples whose special characteristics could be used to show that adherence to the completeness assumption compels one to adopt ‘unnatural theoretical interpretations’. It was a way not of disproving the conventional interpretation by attempting to locate in it some logical flaw, but of pushing it into a corner that in Einstein's view no one would seriously want to inhabit. The paper of Einstein, Podolsky & Rosen (EPR) (1935) is the most famous component of this programme and the purpose of this chapter is to analyse the extent to which the arguments presented in it are compatible with the quantum theory of motion.

Questioning of quantum information Guolin Wu The Center of Philosophy and Technology, School of Marxism South China University of Technology, Guangzhou, Guangdong, P. R. China. E-Mails: ssglwu@scut.edu.cn * The Center of Philosophy and Technology, School of Marxism. South China University of Technology, Guangzhou, Guangdong, P. R. China,510640; Tel.:0086-13660190516; Fax: 0086-2087114979 Accepted: 19 February 2015

In this paper we argue that physical theories, including the most recent ones, even if only implicitly, talk of `objects' (or `things') of some sort (really, of several sorts), and question the logico-mathematical apparatus we still use to formulate them, taking into account what such theories presuppose about these entities. I shall point out that despite the discourse (or at least some discourses) goes in the direction of assuming that these quantum objects would be `new entities' of some kind, distinct from the traditional physical objects of classical physics, the logico-mathematical framework we use is still the old one, grounded on classical logic and set theory, which are committed to atavistic concepts based on individuals and distinguishable things, in complete disagreement with our present day conception of quanta. So, the use of such apparatus would impede us to be in complete agreement with the ontological commitment the theories of \textit{quanta} seem to propose. Thus, I move in the direction of joining those who try to question the `logic of quantum mechanics' from a different point of view, looking for a formal rationale for a new ontology. As a consequence of this move, we can revisit Einstein's ideas on physical reality and see that, from the perspective of considering a new kind of object, here termed `non-individuals', it is possible to sustain that they still obey some of Einstein's conditions for `physical realities', so that it will be possible to talk of a `principle of separability' in a sense which is not in complete disagreement with quantum mechanics. So, Einstein's departure from quantum mechanics might be softened at least concerning a form of his realism (locality still remains a challenge of course), for we guess that the incompatibility between quantum mechanics (field theories included) and some form of `separability' makes sense only if the objects of discourse are thought as `classical' objects, typical of classical ontology.

<i>The World in the Wave Function</i>

Information causality, the Tsirelson bound, and the ‘being-thus’ of things