Supraleitfähigkeit und Superfluidität sind die einzigen bekannten makroskopischen Quantenphänomene. Ihre Untersuchung liefert interessante Hinweise, um einige der Fragen zu verstehen, die mit den Grenzen der Gültigkeit der Quantenmechanik verbunden sind. In diesem Aufsatz wollen wir den Prozeß entzifferen, durch den ein beobachtetes unerwartetes Phänomen in ein physikalisches Problem übergeführt wird, und wir zeigen die kontinuierliche Reinterpretation der Begriffe, um eine zufriedenstellende Erklärung der Supraleitfähigkeit und Superfluidität zu erreichen.

Durch eine Untersuchung der Stoßvorgänge wird die Auffassung entwickelt, daß die Quantenmechanik in der Schrödingerschen Form nicht nur die stationären Zustände, sondern auch die Quantensprünge zu beschreiben gestattet.

Kaum eine Äußerung Einsteins ist so bekannt wie sein Wort, dass Gott nicht würfelt. In ähnlicher Weise, wie Einstein dies unerläutert gelassen hat, ist seine gesamte Position zur Quantenmechanik, auf die es sich bezieht, von Uneindeutigkeiten nicht frei geblieben. Für seine Würfelmetapher ergibt sich ein Spielraum von gegensätzlichen Sichtweisen. Sie lässt sich zum einen mit jüngeren Forschungsresultaten verbinden und weist zum anderen auf rückschrittliche Elemente in Einsteins Denken hin. Ich wende mich zuerst diesen Elementen zu und betrachte dann eine (...) dazu entgegengerichtete Interpretationsvariante, die an den neueren Resultaten anknüpft. (shrink)

It has often been claimed that without drastic conceptual innovations a genuine explanation of quantum interference effects and quantum randomness is impossible. This book concerns Bohmian mechanics, a simple particle theory that is a counterexample to such claims. The gentle introduction and other contributions collected here show how the phenomena of non-relativistic quantum mechanics, from Heisenberg's uncertainty principle to non-commuting observables, emerge from the Bohmian motion of particles, the natural particle motion associated with Schrödinger's equation. (...) This book will be of value to all students and researchers in physics with an interest in the meaning of quantum theory as well as to philosophers of science. (shrink)

Zuerst werden die Argumente rekonstruiert, die dafür sprechen, Einsteins Wort, dass Gott nicht würfelt, als Ausdruck eines überholten deterministischen Weltbildes anzusehen. Anschließend werden Forschungsergebnisse der letzten Jahrzehnte benannt, die für eine Neubewertung seiner Position zur dominanten Interpretation der Quantenmechanik sprechen. Den Abschluß bildet die Diskussion der Möglichkeiten einer Reinterpretation seines Satzes vom nicht würfelnden Gott.

This publication is an appreciation of the natural philosophy and epistemology of the philosopher Grete (Henry-)Hermann. A student of the mathematician Emmy Noether and the philosopher Leonard Nelson, she was one of the early interpreters of quantum mechanics. Werner Heisenberg memorialized her in his book "The Part and the Whole". For the first time, her writings on natural philosophy and epistemology are collected in one volume. An extensive introduction by various authors introduces the work of Grete Henry-Hermann. This (...) edition is supplemented by excerpts from correspondence on natural philosophical and epistemological topics, including correspondence with Carl Friedrich von Weizsäcker, Werner Heisenberg, and Gustav Heckmann. Contents ● Grete Henry-Hermann's contribution to the interpretation of quantum mechanics ● Grete Henry-Hermann's work on the relationship between modern physics and transcendental philosophy ● Grete Hermann's dissertation: The Question of the Finitely Many Steps in the Theory of Polynomial Ideals (1925) ● Discussions on the question of free will and the significance of behavioral research for the critique of reason ● Excerpts from correspondence from 1925 to 1982. (shrink)

ZUSAMMENFASSUNGIm religionsphilosophischen Kontext wurde die Quantenmechanik vielfach bemht, das Argument der Willensfreiheit als naturwissenschaftliche Theorie zu sttzen. Der probabilistische Charakter der Theorie schien eine natrliche Basis fr den Indeterminismus und somit fr sittlich relevante Willensfreiheit zu bieten. Dieser Position wurde jedoch des fteren entgegen gehalten, dass erstens nur bestimmte Interpretationen der Quantenmechanik indeterministisch sind. Zweitens sollen mikroskopische Quanten-Effekte die makroskopische Hirndynamik nicht beeinflussen. Inzwischen mutet die Diskussion immer undurchschaubarer und themenspezifischer an, so dass eine sachgerechte Beurteilung geradezu als (...) undurchfhrbar erscheint. Die vorliegende Untersuchung zielt darauf, durch Klrung der Begrifflichkeit bestehende Konfusionen zu entwirren und konzeptionelle Konturen zu zeichnen, die es ermglichen, bisherige Debatten zu systematisieren sowie fr zuknftige Untersuchungen als methodisch-strukturelle Grundlage zu dienen.SUMMARYIt is often claimed that the probabilistic character of quantum mechanics supports ontological indeterminism and in consequence free will. Theologians especially believe that they have found an empirical argument for the free will defense. Critics argue, however, that there is no evidence that microscopic quantum phenomena could affect macroscopic brain dynamics, nor does the probabilistic character of quantum formalism necessarily imply ontological indeterminism. In the present paper I shall examine whether the critique holds, and point out the relevance of quantum mechanics for theological investigations. (shrink)

Lifeworld realism and quantum-physical realism are taken as experience-dependent conceptions of the world that become objects of explicit reflection when confronted with context-external discourses. After a brief sketch of the two contexts of experience—lifeworld and quantum physics—and their realist interpretations, I will discuss the quantum world from the perspective of lifeworld realism. From this perspective, the quantum world—roughly speaking—has to be either unreal or else constitute a different reality. Then, I invert the perspective and examine the (...) lifeworld from the standpoint of quantumphysical realism. This conception of the lifeworld has gained momentum from new research results in recent decades. Despite its experiential basis, quantum-physical realism bears an ambiguity akin to that of lifeworld realism. While the perspectival inversion serves to highlight the problem, it also contributes to an improved understanding of lifeworld-realism. (shrink)

Lebenswelt und Physik stehen nicht nur unverkennbar miteinander in Beziehung, sondern prägen jeweils auch eigenständig die Struktur moderner Gesellschaften. Während die Lebenswelt mit ihrem traditionellen Bezug auf unmittelbare Wahrnehmungs- und Handlungsformen immer noch die lokale Reproduktion bestimmt, begründen physikalische Verfahren und Erkenntnisse die materiellen Techniken der globalisierten Zivilisation. Den Abstand von Lebenswelt und Physik, wie die zwischen ihnen bestehenden Beziehungen, möchte ich an den für sie typischen Raumbegriffen erläutern. Meine These ist, dass jedenfalls einige Raumbegriffe der modernen Physik den lebensweltlichen (...) Raumbegriffen entgegengesetzt sind. Mein Beispiel werden Aspekte des Raumbegriffes sein, die sich an Interpretationen der Quantenmechanik anschließen. Ich möchte außerdem zeigen, dass andere physikalische Raumbegriffe der Lebenswelt näher stehen als die der Quantenmechanik. Als Beispiel für einen solchen Begriff werde ich den klassischen und immer noch aktuellen aus Isaac Newtons Mechanik diskutieren. Grob gesprochen, steht Newtons Raumvorstellung zwischen der modernen physikalischen und der lebensweltlichen Raumvorstellung. (shrink)

In this paper we present a new categorical approach which attempts to provide an original understanding of QM. Our logos categorical approach attempts to consider the main features of the quantum formalism as the standpoint to develop a conceptual representation that explains what the theory is really talking about —rather than as problems that need to be bypassed in order to allow a restoration of a classical “common sense” understanding of what there is. In particular, we discuss a solution (...) to Kochen-Specker contextuality through the generalization of the meaning of global valuation. This idea has been already addressed by the so called topos approach to QM —originally proposed by Isham, Butterfiled and D ̈oring— in terms of sieve-valued valuations. The logos approach to QM presents a different solution in terms of the notion of intensive valuation. This new solution stresses an ontological reading of the quantum formalism and the need to restore an objective conceptual representation and understanding of quantum physical reality. (shrink)

A longstanding issue in attempts to understand the Everett (Many-Worlds) approach to quantum mechanics is the origin of the Born rule: why is the probability given by the square of the amplitude? Following Vaidman, we note that observers are in a position of self-locating uncertainty during the period between the branches of the wave function splitting via decoherence and the observer registering the outcome of the measurement. In this period it is tempting to regard each branch as equiprobable, (...) but we argue that the temptation should be resisted. Applying lessons from this analysis, we demonstrate (using methods similar to those of Zurek's envariance-based derivation) that the Born rule is the uniquely rational way of apportioning credence in Everettian quantum mechanics. In doing so, we rely on a single key principle: changes purely to the environment do not affect the probabilities one ought to assign to measurement outcomes in a local subsystem. We arrive at a method for assigning probabilities in cases that involve both classical and quantum self-locating uncertainty. This method provides unique answers to quantum Sleeping Beauty problems, as well as a well-defined procedure for calculating probabilities in quantum cosmological multiverses with multiple similar observers. (shrink)

Beyond Weimar Culture – The Significance of the Forman Thesis for a Cultural Approach to the History of Science. The famous ‘Forman thesis’, published in 1971, argued for a historical linkage among the intellectual atmosphere of Weimar Germany, popular revolts against determinism and materialism, and the creation of the revolutionary new theory of quantum mechanics. Paul Forman's long essay on “Weimar Culture” has shaped research agendas in numerous fields, from the history and philosophy of physics to German history (...) to the sociology of scientific knowledge. Despite its status as a classic and its transformative effect, Weimar Culture has always inspired as much critique as assent. In particular in the history of science, cohorts of students and two generations of scholars have debated the Forman thesis as a conceptual tool for linking scientific change with cultural processes. The Forman thesis raises critical questions for both the ongoing debates over cultural approaches to the history of science and the burgeoning newer scholarship on physics in and beyond Weimar Germany. Exploring these implications has been the aim of a transnational project of the three authors of this article which sheds some light on these debates and briefly introduces the following papers of this special issue devoted to Paul Forman and his seminal works in the history of science. (shrink)

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

The primitive ontology approach to quantum mechanics seeks to account for quantum phenomena in terms of a distribution of matter in three-dimensional space and a law of nature that describes its temporal development. This approach to explaining quantum phenomena is compatible with either a Humean or powerist account of laws. In this paper, I offer a powerist ontology in which the law is specified by Bohmian mechanics for a global configuration of particles. Unlike in other (...) powerist ontologies, however, this law is not grounded in a structural power that is instantiated by the global configuration. Instead, I combine the primitive ontology approach with Aristotle’s doctrine of hylomorphism to create a new metaphysical model, in which the cosmos is a hylomorphic substance with an intrinsic power to choreograph the trajectories of the particles. (shrink)

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

It has been argued that measurement-induced collapses in Orthodox Quantum Mechanics generates an intrinsic (or built-in) quantum arrow of time. In this paper, I critically assess this proposal. I begin by distinguishing between an intrinsic and non-intrinsic arrow of time. After presenting the proposal of a collapse-based arrow of time in some detail, I argue, first, that any quantum arrow of time in Orthodox Quantum Mechanics is non-intrinsic since it depends on external information about (...) the measurement context, and second, that it cannot be global, but just local. I complement these arguments by assessing some criticisms and considerations about the implementation of time reversal in contexts wherein measurement-induced collapses work. I conclude that the quantum arrow of time delivered by Orthodox Quantum Mechanics is much weaker than usually thought. (shrink)

ion turns equivalence into identity, but there are two ways to do it. Given the equivalence relation of parallelness on lines, the #1 way to turn equivalence into identity by abstraction is to consider equivalence classes of parallel lines. The #2 way is to consider the abstract notion of the direction of parallel lines. This paper developments simple mathematical models of both types of abstraction and shows, for instance, how finite probability theory can be interpreted using #2 abstracts as “superposition (...) events” in addition to the ordinary events. The goal is to use the second notion of abstraction to shed some light on the notion of an indefinite superposition in quantum mechanics. (shrink)

Deutsch and Hayden have proposed an alternative formulation of quantum mechanics which is completely local. We argue that their proposal must be understood as having a form of ‘gauge freedom’ according to which mathematically distinct states are physically equivalent. Once this gauge freedom is taken into account, their formulation is no longer local.

By means of the examples of classical and Bohmian quantum mechanics, we illustrate the well-known ideas of Boltzmann as to how one gets from laws defined for the universe as a whole to dynamical relations describing the evolution of subsystems. We explain how probabilities enter into this process, what quantum and classical probabilities have in common and where exactly their difference lies.

Zur Aufklärung der vielschichtigen Beziehungen zwischen Lebenswelt und Physik diskutiere ich die für die beiden Erfahrungsweisen jeweils typischen Konzeptualisierungen von Zeit. Nach einer Einleitung beginne ich mit der Analyse der subjektiven und objektiven lebensweltlichen Zeitformen. Anschließend erörtere ich im dritten Abschnitt das Verhältnis von lebensweltlichen und physikalischen Elementen der Weltzeit. Vier physikalische Zeitverständnisse stelle ich in ihrer Differenz zur lebensweltlichen Auffassung im vierten Abschnitt dar. Historisch hat sich die generelle Tendenz zur Vergrößerung dieser Differenz fortgesetzt, ohne dass schon Instanzen zur (...) Vermittlung der divergierenden Begriffe entstanden wären. Vor diesem Hintergrund plädiere ich im abschließenden Teil für eine plurale Begrifflichkeit. (shrink)

The previous three articles have discussed scientific ontology, resolving the contradictions between quantum mechanics and relativity using the cosmic origin philosophical framework, and interpreting the principles of natural philosophy through physics. Aristotle established material philosophy and material science, relegating the philosophical concepts of cosmic ontology and the cosmic origin to metaphysics and theology. As a result, philosophy was divided into first philosophy and second philosophy as scientific considerations. When material science developed into the ontology of the universe, able (...) to explain the cosmic origin principle, a major issue arose: after 2500 years of development, humanity has only grasped the meaning of “matter.” Yet, what are “energy” and “information”? We still haven’t figured that out. Modern physics has brought both benefits and contradictions to humanity. To resolve these contradictions, we need to redefine the scientific consideration of “philosophy” and its philosophical concepts. This article continues to explore the contradictions between quantum mechanics and relativity using the principles of cosmic origin, reflecting on the basic concepts of philosophy and human thought. (shrink)

is every bit as intelligible and philosophically respectable as many other doctrines currently in favor, e.g., the doctrine that mental events are identical with brain events; the attempt to give a linguistic construal of this latter doctrine meets many of the same sorts of difficulties encountered above (see Hempel, op. cit.). Secondly, I think that evidence for universal determinism may not, as a matter of fact, be so hard to come by as one might imagine. It is a striking fact (...) about our world that we never observe any genuine cases of parallelism; it always seems possible to design some sort of interaction between any two genuine empirical magnitudes. If this is correct, then a true theory T can be deterministic only if universal determinism reigns. (shrink)

At the 1927 Como conference Bohr spoke the famous words “It is wrong to think that the task of physics is to find out how nature is. Physics concerns what we can say about nature.” However, if the Copenhagen interpretation really adheres to this motto, why then is there this nagging feeling of conflict when comparing it with realist interpretations? Surely what one can say about nature should in a certain sense be interpretation independent. In this paper I take Bohr’s (...) motto seriously and develop a quantum logic that avoids assuming any form of realism as much as possible. To illustrate the non-triviality of this motto, a similar result is first derived for classical mechanics. It turns out that the logic for classical mechanics is a special case of the quantum logic thus derived. Some hints are provided as to how these logics are to be used in practical situations and finally, I discuss how some realist interpretations relate to these logics. (shrink)

Werner Heisenberg hat einen wichtigen, noch nicht hinreichend untersuchten Beitrag zum Wandel des neuzeitlichen Wissenschaftsverständnisses geleistet. Der Wandel führte von der Charakterisierung des wissenschaftlichen Wissens als sichere Erkenntnis zu seiner - heute weithin anerkannten - Charakterisierung als bloß hypothetische Erkenntnis. Anfänge dieses Wandlungsprozesses lassen sich im 19. Jahrhundert nachweisen (z.B. bei John Hersehel, William Whewell oder Hermann von Helmholtz). Ich möchte am Beispiel von Heisenberg der Frage nachgehen, welchen Einfluss die Begründung der Quantenmechanik, die seine Wissenschaftsauffassung prägte, auf den (...) Prozess der Relativierung von Geltungsansprüchen hatte. Meine Vermutung ist, dass eine entscheidende Rolle hierbei weniger dem Wahrscheinlichkeitsbegriff als vielmehr dem Wahrheits- und Realitätsbegriff zukam. Ich werde als erstes den historischen Prozess der Hypothetisierung von Geltungsansprüchen, zu dem ich Heisenbergs Konzeption ins Verhältnis setzen möchte, charakterisieren. Anschließend rekonstruiere ich Heisenbergs Konzeption, soweit sie sich seinen populären Reden und Aufsätzen entnehmen lässt. Als drittes werde ich ihre Wirkungsgeschichte kurz ansprechen und sie mit Wissenschaftsauffassungen vergleichen, die die Bedeutung des Hypothetischen für die modernen Theorien der Naturwissenschaften betonen. Ihnen gegenüber erweist sich Heisenbergs Beitrag als durchaus eigenständig. (shrink)

Applying the resolution–scale relativity principle to develop a mechanics of non-differentiable dynamical paths, we find that, in one dimension, stationary motion corresponds to an Itô process driven by the solutions of a Riccati equation. We verify that the corresponding Fokker–Planck equation is solved for a probability density corresponding to the squared modulus of the solution of the Schrödinger equation for the same problem. Inspired by the treatment of the one-dimensional case, we identify a generalization to time dependent problems in (...) any number of dimensions. The Itô process is then driven by a function which is identified as establishing the link between non-differentiable dynamics and standard quantum mechanics. This is the basis for the scale relativistic interpretation of standard quantum mechanics and, in the case of applications to chaotic systems, it leads us to identify quantum-like states as characterizing the entire system rather than the motion of its individual constituents. (shrink)

It is well known that successive observations of the instantaneous state of a decaying system lead to a modified decay law. In the limit of infinitely frequent observations, the modified lifetime becomes infinite (“Zeno's paradox”). We study here the behavior of decaying systems under continuous rather than successive observations. Such continuous observation is achieved by a permanent coupling of the decaying system to a counter, which is sufficiently sensitive to the presence of the decay products. For two explicitly soluble models (...) we obtain a result very similar to Zeno's paradox: The observation again strongly modifies the decay law, and prevents the decay completely in the limit of a perfect (i.e., infinitely sensitive) counter. Like Zeno's paradox, however, this “watchdog effect” is not very likely to be detected in actual experiments, e.g., with radioactive nuclei. (shrink)

The universality assumption (“U”) that quantum wave states only evolve by linear or unitary dynamics has led to a variety of paradoxes in the foundations of physics. U is not directly supported by empirical evidence but is rather an inference from data obtained from microscopic systems. The inference of U conflicts with empirical observations of macroscopic systems, giving rise to the century-old measurement problem and subjecting the inference of U to a higher standard of proof, the burden of which (...) lies with its proponents. This burden remains unmet because the intentional choice by scientists to perform interference experiments that only probe the microscopic realm disqualifies the resulting data from supporting an inference that wave states always evolve linearly in the macroscopic realm. Further, the nature of the physical world creates an asymptotic size limit above which interference experiments, and verification of U in the realm in which it causes the measurement problem, seem impossible for all practical purposes if nevertheless possible in principle. This apparent natural limit serves as evidence against an inference of U, providing a further hurdle to the proponent’s currently unmet burden of proof. The measurement problem should never have arisen because the inference of U is entirely unfounded, logically and empirically. (shrink)

In this paper I consider the problem of interpreting quantum mechanics. I argue that this problem has evolved in part into the problem of selecting tenable interpretations from a set of available interpretations. We lack the means to make this selection. There is consensus that interpretations should be consistent and empirically adequate. But these conditions are not particularly discriminative. Other conditions may be discriminative but are not generally accepted. I propose two new conditions for selecting tenable interpretations, motivated (...) by the use of quantum mechanics in technology. The first requires that interpretations ascribe the physical properties to technical artefacts that are entailed by the ascription of technical functions to those artefacts. The second requires that they ascribe the physical properties represented by engineering sketches of those artefacts. I consider the example of quantum teleportation in some detail. Introduction The problem of interpreting quantum mechanics Technical functions Decoders in quantum teleportation Engineering sketches Conclusions Appendix: Quantum teleportation. (shrink)

The purpose of this article is to establish a connection between modelling practices and interpretive approaches in quantum mechanics, taking as a starting point the literature on scientific representation. Different types of modalities play different roles in scientific representation. I postulate that the way theoretical structures are interpreted in this respect affects the way models are constructed. In quantum mechanics, this would be the case in particular of initial conditions and observables. I examine two formulations of (...) quantum mechanics, the standard wave-function formulation and the consistent histories formulation, and show that they correspond to opposite stances, which confirms my approach. Finally, I examine possible strategies for deciding between these stances. (shrink)

One problem with assessing quantum logic is that there are considerable differences between its practitioners. In particular they offer different versions of the set of sentences which the logic governs. On some accounts the sentences involved describe events, on others they are ascriptions of properties. In this paper a framework is offered within which to discuss different quantum logical interpretations of quantum theory, and then the works of Jauch, Putnam, van Fraassen and Kochen are located within it.

In his paper titled ‘Against “measurement” ’ [Physics World 3(8), 33–40 [1990]], Bell criticised arguments that use the concept of measurement to justify the statistical interpretation of quantum theory. Among these was the text of Gottfried [Quantum Mechanics (Benjamin, New York, [1966])]. Gottfried has replied to this criticism, claiming to show that, for systems with both continuous and discrete degrees of freedom, the statistical interpretation for the discrete variables is implied by requiring that the continuous variables are (...) described classically. In the present paper, Gottfried’s argument is criticised. It is suggested that he takes over aspects of classical physics which are in conflict with the classical limit of the Schrödinger equation. He incorrectly assumes that, in the output from a Stern-Gerlach apparatus, the wave-function of any ion is restricted to one or another of the beams. (shrink)

The four antinomies of Zeno of Elea continue to be provoking issues that remain relevant for the foundation of science. Aristotle used this antinomy to arrive at a deeper understanding of movement : it is a fluent continuum that he considers to be a whole. The parts, if any, are only potentially present. Similarly, quantum mechanics states that movement is quantized ; things move or change in nonreducible steps, the so-called quanta. This view is in contrast to classical (...) mechanics, where infinitesimally small steps are permitted. The objective of the present study is to show the merits of the Aristotelian approach. Examples from modern science serve to illustrate the philosophical statements. (shrink)