Institute of Theoretical Physics, Exact Sciences Sidlerstrasse 5, University of Bern, CH-3012 Bern Switzerland portmann{at}itp.unibe.ch' + u + '@' + d + ''//--> awuethr{at}itp.unibe.ch' + u + '@' + d + ''//--> John Bell showed that a big class of local hidden-variable models stands in conflict with quantum mechanics and experiment. Recently, there were suggestions that empirically adequate hidden-variable models might exist which presuppose a weaker notion of local causality. We will show that a Bell-type inequality can be derived also (...) from these weaker assumptions. Introduction The EPR-Bohm experiment Local causality Bell's inequality from separate common causes 4.1 A weak screening-off principle 4.2 Perfect correlation and ‘determinism’ 4.3 A minimal theory for spins 4.4 No conspiracy Discussion. (shrink)

In 1949, Richard Feynman published the essentials of his solution to the recalcitrant problems that plagued quantum theories of electrodynamics of his days. The main problem was that the theory, that was considered to be correct and often led to correct observable consequences, also implied that some quantities should be infinite, while by common sense or empirical evidence they were finite. Feynman devised a method of solving the relevant theoretical equations in which particular combinations of elementary solutions yielded empirically adequate (...) results even when applied to complex problems. The combination of the basic solutions was guided by relatively simple graphical considerations... (shrink)

I reconstruct the discovery of the Higgs boson by the ATLAS collaboration at CERN as the application of a series of inferences from effects to causes. I show to what extent such diagnostic causal inferences can be based on well established knowledge gained in previous experiments. To this extent, causal reasoning can be used to infer the existence of entities, rather than just causal relationships between them. The resulting account relies on the principle of causality, attributes only a heuristic role (...) to the theory’s predictions, and shows how, and to what extent, data selection can be used to exclude alternative causes, even “unconceived” ones. (shrink)

I give a brief introduction to how Feynman diagrams are used. I review arguments to the effect that they are only used as calculation tools and should not be interpreted as representations of physical processes. Against these arguments, I propose to regard Feynman diagrams as visual models that explain, in some respects, how elementary particles interact.

A fair amount of recent scholarship has been concerned with correcting a supposedly wrong, but wide-spread, assessment of the consequences of the empirical falsification of Bell-type inequalities. In particular, it has been claimed that Bell-type inequalities follow from “locality tout court” without additional assumptions such as “realism” or “hidden variables”. However, this line of reasoning conflates restrictions on the spatio-temporal relation between causes and their effects (“locality”) and the assumption of a cause for every event (“causality”). It thus fails to (...) recognize a substantial restriction of the class of theories that is falsified through Bell-type inequalities. (shrink)

Arguably, the development of Feynman diagrams not only resulted in a useful tool for calculations but also brought about deep conceptual changes in the theory of quantum electrodynamics. Starting from this thesis, I try to bring to the fore a particular aspect of it. I maintain that the function of Feynman diagrams is not exhausted by their use in the application of the finished theory to concrete cases. Rather, Feynman diagrams are one of the results of Feynman's more general search (...) for appropriate means of representation. Accordingly, the development of Feynman diagrams is a characteristic example of Feynman's heuristics. (shrink)

I present first results of my analysis of a collection of about 24,000 email messages from internal mailing lists of the ATLAS collaboration, at CERN, the particle physics laboratory, during the years 2010–2013. I represent the communication on these mailing lists as a network in which the members of the collaboration are connected if they reply to each other’s messages. Such a network allows me to characterize the collaboration from a bird’s eye view of its communication structure in epistemically relevant (...) terms. I propose to interpret established measures such as the density of the network as indicators for the degree of “collaborativeness” of the collaboration and the presence of “communities” as a sign of cognitive division of labor. Similar methods have been used in philosophical and historical studies of collective knowledge generation but mostly at the level of information exchange, cooperation and competition _between_ individual researchers or small groups. The present article aims to take initial steps towards a transfer of these methods and bring them to bear on the processes of collaboration _inside_ a “collective author.”. (shrink)

In this note, I briefly review Lyre's analysis and interpretation of the Higgs mechanism. Contrary to Lyre, I maintain that, on the proper understanding of the term, the Higgs mechanism refers to a physical process in the course of which gauge bosons acquire a mass. Since also Lyre's worries about imaginary masses can be dismissed, a realistic interpretation of the Higgs mechanism seems viable.

John Bell showed that a big class of local hidden-variable models stands in conflict with quantum mechanics and experiment. Recently, there were suggestions that empirically adequate hidden-variable models might exist which presuppose a weaker notion of local causality. We will show that a Bell-type inequality can be derived also from these weaker assumptions.

This white paper outlines the plans of the History Philosophy Culture Working Group of the Next Generation Event Horizon Telescope Collaboration.

In the light of recent discussions we present the main results of our project, the aim of which was to derive a Bell-type inequality from the weakest possible assumptions. A principal outcome of the project is that a Bell-type inequality can be derived from the assumption of separate common causes (Graßhoff, Portmann and Wüthrich 2005), even without the assumption of perfectly anticorrelating event types (Portmann and Wüthrich 2007). We also address the critique that in Graßhoff et al. (2005) we implicitly (...) assume a common common cause (Hofer-Szabó forthcoming). (shrink)

I give a response to Adrian Wüthrich’s critical review of my analysis of the Higgs mechanism, in which I try to clarify some possible misunderstandings. I concede that, as Wüthrich points out, many physicists see the Higgs mechanism as the roll-over from a symmetrical potential in the initial Lagrangian to a symmetry-breaking potential, while my former analysis had basically focused on the gauge-invariant transformation of the initial Lagrangian into the intended form. My main contention, however, still is that neither (...) Higgs story has (as yet) much explanatory power. (shrink)

Feynman diagrams: conceptual tools for theoretical physicists Content Type Journal Article Category Book Review Pages 1-4 DOI 10.1007/s11016-011-9580-y Authors Laurie M. Brown, Department of Physics and Astronomy, Northwestern University, Evanston, IL 60201, USA Journal Metascience Online ISSN 1467-9981 Print ISSN 0815-0796.

ABSTRACT Unlike the relativity theory it seeks to replace, causal set theory has been interpreted to leave space for a substantive, though perhaps ‘localized’, form of ‘becoming’. The possibility of fundamental becoming is nourished by the fact that the analogue of Stein’s theorem from special relativity does not hold in CST. Despite this, we find that in many ways, the debate concerning becoming parallels the well-rehearsed lines it follows in the domain of relativity. We present, however, some new twists and (...) challenges. In particular, we show that a novel and exotic notion of becoming is compatible with causal sets. In contrast to the localized becoming considered compatible with the dynamics of CST by its advocates, our novel kind of becoming, while not answering to the typical A-theoretic demands, is global and objective. _1_ Introduction _2_ The Basics of Causal Set Theory _3_ Facing the Same Dilemma? _4_ Taking Growth Seriously _5_ Conclusion. (shrink)

Philosophy Beyond Spacetime assesses the state of play in the philosophy of quantum gravity. Research in this field aims at a unified theory in which quantum matter is related dynamically to relativistic spacetime. This volume highlights the conceptual questions involved, showing how physics and metaphysics can illuminate each other.

A growing body of empirical evidence suggests that folk knowledge attribution practices regarding some epistemological thought experiments differ significantly from the consensus found in the philosophical literature. More specifically, laypersons are likely to ascribe knowledge in the so-called Authentic Evidence Gettier-style cases, while most philosophers deny knowledge in these cases. The intuitions shared by philosophers are often used as evidence in favor (or against) certain philosophical analyses of the notion of knowledge. However, the fact that these intuitions are not universal, (...) as non-philosophers do not sympathize with verdicts made by philosophers, is problematic and requires some explanation. Recently, a promising theoretical approach emerged that could be used to explain away unexpected folk knowledge attributions. According to the protagonist projection hypothesis, when subjects answer questions about some hypothetical scenario, their judgments might result from adopting the cognitive perspective of the protagonist in the given scenario. Previous experimental findings suggest protagonist projection might be responsible for problematic knowledge attributions in Gettier-style cases. This paper reports data collected in an experiment which focused on five different Authentic Evidence Gettier-style scenarios and investigated the impact of protagonist projection on folk knowledge ascriptions in such cases. The results bring some support to the protagonist projection hypothesis, but do not allow to explain away a substantial number of problematic folk knowledge attributions. (shrink)

Francis Ysidro Edgeworth’s unduly neglected monograph New and Old Methods of Ethics (1877) advances a highly sophisticated and mathematized account of social well-being in the utilitarian tradition of his 19th-century contemporaries. This article illustrates how his usage of the ‘calculus of variations’ was combined with findings from empirical psychology and economic theory to construct a consequentialist axiological framework. A conclusion is drawn that Edgeworth is a methodological predecessor to several important methods, ideas, and issues that continue to be discussed in (...) contemporary social well-being studies. (shrink)

Since the early seventeenth century of Bacon, Gallileo and Descartes, the relations between science and religion as well as mind and body have remained volatile fault lines of conflict. The controversies surrounding these relations are as alive and pressing now as at any point over the course of the past four centuries. Adrian Johnston's transcendental materialism offers a new theoretical approach to these issues. Arming himself with resources provided by German idealism, Marxism, psychoanalysis, the life sciences and contemporary philosophical (...) developments, Johnston formulates an account of subjectivity that, although being both materialist and naturalist, does full justice to human beings as irreducible to natural matter alone. At the same time he argues against relapses into idealisms, dualisms and spiritualisms. Adventures in Transcendental Materialism elaborates Johnston's position through critical engagements with some of today's most important thinkers including Slavoj Žižek, Alain Badiou, Catherine Malabou, Jean-Claude Milner, Martin Hägglund, William Connolly, and Jane Bennett"--Back cover. (shrink)

This paper is an enquiry into the logical, metaphysical, and physical possibility of time travel understood in the sense of the existence of closed worldlines that can be traced out by physical objects. We argue that none of the purported paradoxes rule out time travel either on grounds of logic or metaphysics. More relevantly, modern spacetime theories such as general relativity seem to permit models that feature closed worldlines. We discuss, in the context of Gödel's infamous argument for the ideality (...) of time based on his eponymous spacetime, what this apparent physical possibility of time travel means. Furthermore, we review the recent literature on so-called time machines, i.e., of devices that produce closed worldlines where none would have existed otherwise. Finally, we investigate what the implications of the quantum behaviour of matter for the possibility of time travel might be and explicate in what sense time travel might be possible according to leading contenders for full quantum theories of gravity such as string theory and loop quantum gravity. (shrink)

Thought experiments play a role in science and in some central parts of contemporary philosophy. They used to play a larger role in philosophy of science, but have been largely abandoned as part of the field’s “practice turn”. This chapter discusses possible roles for thought experimentation within a practice-oriented philosophy of science. Some of these roles are uncontroversial, such as exemplification and aiding discovery. A more controversial role is the reliance on thought experiments to justify philosophical claims. It is proposed (...) that if we adopt an underlying empiricist view of concepts, then thought experiments can be seen as affording us contact with scientific practice, despite their seemingly a priori character. The advantages and drawbacks of thought experiments are discussed via comparison with case studies, on the one, and simulations on the other hand. The chapter closes with some remarks on how to combine thought experiments with other methods. (shrink)

Thought experiments play a role in science and in some central parts of contemporary philosophy. They used to play a larger role in philosophy of science, but have been largely abandoned as part of the field’s “practice turn”. This chapter discusses possible roles for thought experimentation within a practice-oriented philosophy of science. Some of these roles are uncontroversial, such as exemplification and aiding discovery. A more controversial role is the reliance on thought experiments to justify philosophical claims. It is proposed (...) that if we adopt an underlying empiricist view of concepts, then thought experiments can be seen as affording us contact with scientific practice, despite their seemingly a priori character. The advantages and drawbacks of thought experiments are discussed via comparison with case studies, on the one, and simulations on the other hand. The chapter closes with some remarks on how to combine thought experiments with other methods. (shrink)

Theories of quantum gravity generically presuppose or predict that the reality underlying relativistic spacetimes they are describing is significantly non-spatiotemporal. On pain of empirical incoherence, approaches to quantum gravity must establish how relativistic spacetime emerges from their non-spatiotemporal structures. We argue that in order to secure this emergence, it is sufficient to establish that only those features of relativistic spacetimes functionally relevant in producing empirical evidence must be recovered. In order to complete this task, an account must be given of (...) how the more fundamental structures instantiate these functional roles. We illustrate the general idea in the context of causal set theory and loop quantum gravity, two prominent approaches to quantum gravity. (shrink)

John Scottus Eriugena (d. ca. 877) is regarded as the most important philosopher and theologian in the Latin West from the death of Boethius until the thirteenth century. He incorporated his understanding of Latin sources, Ambrose, Augustine, Boethius and Greek sources, including the Cappadocian Fathers, Pseudo-Dionysius, and Maximus Confessor, into a metaphysics structured on Aristotle's Categories, from which he developed Christian Neoplatonist theology that continues to stimulate 21st-century theologians. This collection of essays provides an overview of the latest scholarship on (...) various aspects of Eriugena's thought and writings, including his Irish background, his use of Greek theologians, his Scripture hermeneutics, his understanding of Aristotelian logic, Christology, and the impact he had on contemporary and later theological traditions. Contributors: David Albertson, Joel Barstad, John Contreni, Christophe Erismann, John Gavin, Adrian Guiu, Michael Harrington, Catherine Kavanagh, A. Kijewska, Stephen Lahey, Elena Lloyd-Sidle, Bernard McGinn, Ernesto Sergio Mainoldi, Dermot Moran, Giulio D'Onofrio, Willemien Otten, and Alfred Siewers. (shrink)

Kuhn claimed that several algorithms can be defended to select the best theory based on epistemic values such as simplicity, accuracy, and fruitfulness. In a recent paper, Okasha :83–115, 2011) argued that no theory choice algorithm exists which satisfies a set of intuitively compelling conditions that Arrow had proposed for a consistent aggregation of individual preference orderings. In this paper, we put forward a solution to avoid this impossibility result. Based on previous work by Gaertner and Xu, we suggest to (...) view the theory choice problem in a cardinal context and to use a general scoring function defined over a set of qualitative verdicts for every epistemic value. This aggregation method yields a complete and transitive ranking and the rule satisfies all Arrovian conditions appropriately reformulated within a cardinal setting. We also propose methods that capture the aggregation across different scientists. (shrink)

There remains no consensus among social scientists as to how to measure and understand forms of information deprivation such as misinformation. Machine learning and statistical analyses of information deprivation typically contain problematic operationalizations which are too often biased towards epistemic elites' conceptions that can undermine their empirical adequacy. A mature science of information deprivation should include considerable citizen involvement that is sensitive to the value-ladenness of information quality and that doing so may improve the predictive and explanatory power of extant (...) models. (shrink)

Recent epistemology has reflected a growing interest in issues about the value of knowledge and the values informing epistemic appraisal. Is knowledge more valuable that merely true belief or even justified true belief? Is truth the central value informing epistemic appraisal or do other values enter the picture? Epistemic Value is a collection of previously unpublished articles on such issues by leading philosophers in the field. It will stimulate discussion of the nature of knowledge and of directions that might be (...) taken by the theory of knowledge. The contributors are Jason Baehr, Michael Brady, Berit Brogaard, Michael DePaul, Pascal Engel, Catherine Elgin, Alvin Goldman, John Greco, Stephen Grimm, Ward Jones, Martin Kusch, Jonathan Kvanvig, Michael Lynch, Erik Olsson, Wayne Riggs and Matthew Weiner. (shrink)

In this article I examine the contemporary discourses and debates that surround the sociology of spirituality, with especial attention to the term “spirituality”. To counter the widespread belief that this term lacks clarity and utility, I suggest reconsidering Max Weber’s use of the term “spirit,” as it refers to a recognisable ethic that results in specific behaviour, while still retaining its religious and spiritual connotations. Through focusing on two influential English figures in the post 9/11 God debate in the West, (...) Richard Dawkins and Karen Armstrong, I provide a brief case study of how Weber’s understanding of “spirit” serves great utility in illuminating what drives the ideas, identity-making and behaviour of contemporary atheists and those defending religion. By utilising Weber’s “spirit,” rather than the term spirituality, I demonstrate that this enables us to dig deep into the social context and backgrounds of these two individuals, and to avoid taking their statements at face value – a common criticism of sociology of spirituality studies. I argue that the use of “spirit,” in terms of a recognisable ethic that results in specific behaviour, would benefit the sociology of spirituality. This is because it grounds the God debaters’ ideas and beliefs in a recognisable human experience that eludes reductive distinctions and disembodied abstractions. (shrink)

In this the second volume of his trilogy, Adrian Johnston delineates the philosophy of nature requisite for a properly materialist theory of irreducible autonomous subjectivity. Bringing to light a hitherto invisible undercurrent linking together Hegelian "Naturphilosophie," Marxian-Engelsian-Leninist dialectical materialism, Freudian-Lacanian psychoanalytic metapsychology, and today's approaches to metaphysics and the philosophy of science on both sides of the analytic-continental divide, he assembles an ontology that dramatically transfors our understandings of figures like Hegel, Marx, Engels, Lenin, Lukács, Freud, Lacan, Althusser, and (...) McDowell. In turn, this work looks to provide answer to the fundamental question: How must nature be conceptualized insofar as it happens to have eventuated in, and continues to contain the structures and dynamics peculiar to, full-fledged subjectivity? According to "A Weak Nature Alone," images of nature as akin to either a machine or organism in which each and every entity and event is governed by unbreakable causal laws preclude satisfying explanations of the emergence of human subjects with their spontaneous and self-determining capacities. Such explanations instead demand what Johnston as a "dialectical naturalism," namely, a materialism of a selfdenaturalizing nature radically altering itself in and through its human offspring. The transcendental materialism on display in "A Weak Nature Alone" is a systematic intervention that changes our senses of the philosophical past as well as the future while moving effortlessly within and between traditions and positions (Western and Soviet Marxisms, continental and analytic philosophy, etc.)"--Provided by publisher. (shrink)

Numerous approaches to a quantum theory of gravity posit fundamental ontologies that exclude spacetime, either partially or wholly. This situation raises deep questions about how such theories could relate to the empirical realm, since arguably only entities localized in spacetime can ever be observed. Are such entities even possible in a theory without fundamental spacetime? How might they be derived, formally speaking? Moreover, since by assumption the fundamental entities cannot be smaller than the derived and so cannot ‘compose’ them in (...) any ordinary sense, would a formal derivation actually show the physical reality of localized entities? We address these questions via a survey of a range of theories of quantum gravity, and generally sketch how they may be answered positively. (shrink)

In prior work, we have argued that spacetime functionalism provides tools for clarifying the conceptual difficulties specifically linked to the emergence of spacetime in certain approaches to quantum gravity. We argue in this article that spacetime functionalism in quantum gravity is radically different from other functionalist approaches that have been suggested in quantum mechanics and general relativity: in contrast to these latter cases, it does not compete with purely interpretative alternatives, but is rather intertwined with the physical theorizing itself at (...) the level of quantum gravity. Spacetime functionalism allows one to articulate a coherent realist perspective in the context of quantum gravity, and to relate it to a straightforward realist understanding of general relativity. (shrink)