We show that the Bohmian approach in terms of persisting particles that move on continuous trajectories following a deterministic law can be literally applied to quantum field theory. By means of the Dirac sea model—exemplified in the electron sector of the standard model neglecting radiation—we explain how starting from persisting particles, one is led to standard QFT employing creation and annihilation operators when tracking the dynamics with respect to a reference state, the so-called vacuum. Since on the level of wave (...) functions, both formalisms are mathematically equivalent, this proposal provides for an ontology of QFT that includes a dynamics of individual processes, solves the measurement problem, and explains the appearance of creation and annihilation events. 1Bohmian Mechanics from Quantum Mechanics to Quantum Field Theory2The Dirac Sea Model3Equilibrium States and the Vacuum4Excitations of the Vacuum and the Fock Space Formalism5The Appearance of Particle Creations and Annihilations6The Merits of the Bohmian Approach. (shrink)

We show that the Bohmian approach in terms of persisting particles that move on continuous trajectories following a deterministic law can be literally applied to QFT. By means of the Dirac sea model – exemplified in the electron sector of the standard model neglecting radiation – we explain how starting from persisting particles, one is led to standard QFT employing creation and annihilation operators when tracking the dynamics with respect to a reference state, the so-called vacuum. Since on the level (...) of wave functions, both formalisms are mathematically equivalent, this proposal provides for an ontology of QFT that includes a dynamics of individual processes, solves the measurement problem and explains the appearance of creation and annihilation events. (shrink)

Philosophical discussions on causal inference in medicine are stuck in dyadic camps, each defending one kind of evidence or method rather than another as best support for causal hypotheses. Whereas Evidence Based Medicine advocates the use of Randomised Controlled Trials and systematic reviews of RCTs as gold standard, philosophers of science emphasise the importance of mechanisms and their distinctive informational contribution to causal inference and assessment. Some have suggested the adoption of a pluralistic approach to causal inference, and an inductive (...) rather than hypothetico-deductive inferential paradigm. However, these proposals deliver no clear guidelines about how such plurality of evidence sources should jointly justify hypotheses of causal associations. We here develop such guidelines by first giving a philosophical analysis of the underpinnings of Hill’s viewpoints on causality. We then put forward an evidence-amalgamation framework adopting a Bayesian net approach to model causal inference in pharmacology for the assessment of harms. Our framework accommodates a number of intuitions already expressed in the literature concerning the EBM vs. pluralist debate on causal inference, evidence hierarchies, causal holism, relevance, and reliability. (shrink)

This article sketches an idealized strategy for the identification of neural correlates of consciousness. The proposed strategy is based on a state space approach originating from the analysis of dynamical systems. The article then focuses on one constituent of consciousness, phenomenal awareness. Several rudimentary requirements for the identification of neural correlates of phenomenal awareness are suggested. These requirements are related to empirical data on selective attention, on completely intrinsic selection and on globally unconscious states. As an example, neuroscientific findings on (...) synchronized γ activity are categorized according to these requirements. (shrink)

In honour of Detlef Dürr, we report on a mathematical rigorous computation of the electric vacuum polarisation current and extract the well-known expression for the second order perturbation. Intermediate steps in the presented calculation demonstrate, to the knowledge of the authors for the first time, mathematical rigorous versions of the combined dimensional and Pauli-Villars regularisation schemes. These are employed as computational tools to infer convenient integral representations during the computation. The said second order expression is determined up to a remaining (...) degree of freedom of a real number–without ill-defined terms from start to end. (shrink)

According to the objective Bayesian approach to inductive logic, premisses inductively entail a conclusion just when every probability function with maximal entropy, from all those that satisfy the premisses, satisfies the conclusion. When premisses and conclusion are constraints on probabilities of sentences of a first-order predicate language, however, it is by no means obvious how to determine these maximal entropy functions. This paper makes progress on the problem in the following ways. Firstly, we introduce the concept of a limit in (...) entropy and show that, if the set of probability functions satisfying the premisses contains a limit in entropy, then this limit point is unique and is the maximal entropy probability function. Next, we turn to the special case in which the premisses are categorical sentences of the logical language. We show that if the uniform probability function gives the premisses positive probability, then the maximal entropy function can be found by simply conditionalising this uniform prior on the premisses. We generalise our results to demonstrate agreement between the maximal entropy approach and Jeffrey conditionalisation in the case in which there is a single premiss that specifies the probability of a sentence of the language. We show that, after learning such a premiss, certain inferences are preserved, namely inferences to inductive tautologies. Finally, we consider potential pathologies of the approach: we explore the extent to which the maximal entropy approach is invariant under permutations of the constants of the language, and we discuss some cases in which there is no maximal entropy probability function. (shrink)

This paper elaborates on relationalism about space and time as motivated by a minimalist ontology of the physical world: there are only matter points that are individuated by the distance relations among them, with these relations changing. We assess two strategies to combine this ontology with physics, using classical mechanics as example: the Humean strategy adopts the standard, non-relationalist physical theories as they stand and interprets their formal apparatus as the means of bookkeeping of the change of the distance relations (...) instead of committing us to additional elements of the ontology. The alternative theory strategy seeks to combine the relationalist ontology with a relationalist physical theory that reproduces the predictions of the standard theory in the domain where these are empirically tested. We show that, as things stand, this strategy cannot be accomplished without compromising a minimalist relationalist ontology. (shrink)

This book seeks to work out which commitments are minimally sufficient to obtain an ontology of the natural world that matches all of today’s well-established physical theories. We propose an ontology of the natural world that is defined only by two axioms: (1) There are distance relations that individuate simple objects, namely matter points. (2) The matter points are permanent, with the distances between them changing. Everything else comes in as a means to represent the change in the distance relations (...) in a manner that is both as simple and as informative as possible. The book works this minimalist ontology out in philosophical as well as mathematical terms and shows how one can understand classical mechanics, quantum field theory and relativistic physics on the basis of this ontology. Along the way, we seek to achieve four subsidiary aims: (a) to make a case for a holistic individuation of the basic objects (ontic structural realism); (b) to work out a new version of Humeanism, dubbed Super-Humeanism, that does without natural properties; (c) to set out an ontology of quantum physics that is an alternative to quantum state realism and that avoids any ontological dualism of particles and fields; (d) to vindicate a relationalist ontology based on point objects also in the domain of relativistic physics. (shrink)

Narrative allegory is distinguished from mythology as reality from symbol; it is, in short, the proper intermedium between person and personification. Where it is too strongly individualized, it ceases to be allegory […]. In the community of scholars of intermedia research, the above quoted citation is commonly regarded as Coleridge’s coining of the term “intermedium” or “intermediality”. However, a short glance at the discursive strategy of his argument emphasizes that his notion of “intermedium” must be closely linked to the poetics (...) and aesthetics of 19th-century romanticism. For the romantic poet, the term of “intermedium” does not point to media relations or intermedia processes but to.. (shrink)

We study questionnaire responses to situations in which sacrificing one life may save many other lives. We demonstrate gender differences in moral judgments: males are more supportive of the sacrifice than females. We investigate a source of the endorsement of the sacrifice: antisocial preferences. First, we measure individual proneness to spiteful behavior, using an experimental game with monetary stakes. We demonstrate that spitefulness can be sizable—a fifth of our participants behave spitefully—but it is not associated with gender. Second, we find (...) that gender is consistently associated with responses even when we account for individual differences in the propensity to spitefulness. (shrink)

As digital media becomes more central to the lives of adolescents, it also becomes increasingly relevant for their sexual communication. Sexting as an important image-based digital medium provides opportunities for self-determined digital communication, but also carries specific risks for boundary violations. Accordingly, sexting is understood either as an everyday, or as risky and deviant behavior among adolescents. In the affectedness of boundary violations gender plays an important role. However, it is still unclear to what extent digital sexual communication restores stereotypical (...) gender roles and restrictive sexuality norms or, alternatively, enables new spaces of possibility. In this sense, current research points to a desideratum regarding adolescents’ orientations toward sexting as a practice between spaces of possibility and boundary violations. This paper discusses the possibilities, but also the risks, of intimate digital communication among adolescents. The main question is, how adolescents themselves perceive sexting practices and how they position themselves between both spaces for possibility and for the exchange of unwanted sexual content. For this purpose, orientations toward normalities and gender of students are reconstructed. To answer these questions, twelve single-sex, group discussions were carried out with students aged 16 and 17 at five different secondary schools in northern Germany. A total of 20 boys and 22 girls took part. The group discussions were structured by a narrative generating guideline. The analysis draws its methodology from the Documentary Method, regarding implicit and explicit forms of knowledge and discourse. It results in a typology of three types with different orientations. The study shows, that most of the students consider sexting to be a risky practice; only one type shows normality in the use of sexting. At the same time, some of the young people are interested in experimenting with image-based intimate digital communication. Further, gender differences in use and affectedness are also documented. In this way, orientations toward gender stereotypes “favor” both the attribution of responsibility to girls, and overlook the responsibility of students who perpetrated the boundary violation. The orientations of adolescents should be taken more into account in research as well as in educational programs for the prevention of sexual violence. (shrink)

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.

Augmented Reality (AR) is commonly defined as a digital layer of information viewed on top of the physical world through a smartphone, tablet or eyewear. Increasingly, this understanding of AR is shifting to a dynamic framework of ‘smart things’, including wearable technology, sensors and artificial intelligence (AI), with the ability to intercede in key moments and to deliver contextual and meaningful experiences. The things that come into context are the logical next steps in an evolutionary development towards computers that are (...) better able to show empathy in relation to people: even more human-oriented, anticipative and ubiquitous. Thus, this outsourcing of meaning to empathic technologies points to one of the fundamental questions concerning the relation of human and technology – the nature of the trust that users place in technology. (shrink)

Epistemic scoring rules are the en vogue tool for justifications of the probability norm and further norms of rational belief formation. They are different in kind and application from statistical scoring rules from which they arose. In the first part of the paper I argue that statistical scoring rules, properly understood, are in principle better suited to justify the probability norm than their epistemic brethren. Furthermore, I give a justification of the probability norm applying statistical scoring rules. In the second (...) part of the paper I give a variety of justifications of norms for rational belief formation employing statistical scoring rules. Furthermore, general properties of statistical scoring rules are investigated. Epistemic scoring rules feature as a useful technical tool for constructing statistical scoring rules. (shrink)

The paper sets out and defends against criticism the claims argued for in the book A minimalist ontology of the natural world.

This paper presents the contributions of Alcindo Flores Cabral, professor of Chemistry at the Faculdade de Agronomia Eliseu Maciel, nowadays part of the Universidade Federal de Pelotas, to chemistry teaching. It is a contribution almost unknown to the Brazilian chemical community, although recognized as valuable by several renowned chemists abroad, like W. Hückel, G. Charlot, F. Strong, E. Fessenden and others. Cabral’s innovative helical representation is presented in connection not only with contemporary representations, but also an incursion is made into (...) the first helical systems proposed, those of Hinrichs and of Baumhauer. Some comments are made not only on Cabral’s Classificação Natural dos Elementos, published in 1946, but also about other texts he wrote for an efficient chemistry teaching. (shrink)

Este artigo apresenta a contribuição de Alcindo Flores Cabral (1907-1982) - professor de química da Faculdade de Agronomia Eliseu Maciel, hoje incorporada à Universidade Federal de Pelotas - ao ensino de química, uma contribuição quase desconhecida pela própria comunidade química brasileira, embora reconhecida como relevante por diversos químicos estrangeiros importantes, como W. Hückel, G. Charlot, F. Strong, E. Fessenden e outros. A inovadora representação helicoidal de Cabral é apresentada não só em conexão com representações contemporâneas, mas também inclui-se uma incursão (...) pelos primeiros sistemas helicoidais propostos, os de Hinrichs e de Baumhauer. Apresentam-se alguns comentários não somente sobre a Classificação natural dos elementos, publicada em 1946, mas também sobre outros textos escritos para tornar mais eficaz o ensino de química. (shrink)

O presente trabalho examina os aspectos históricos da extração do óleo de canela-sassafrás (Ocotea pretiosa Mez), rico em safrol, no Alto e Médio Vale do Itajaí, a partir de 1940, por iniciativa de Otto Grimm, no município de Rio do Sul. Apresenta-se o tema no contexto da memória química em Santa Catarina, e discutem-se os procedimentos utilizados, e principalmente os motivos que levaram tal indústria incipiente a não se converter em uma indústria de química fina. Para tanto, são apresentados alguns (...) dados pertinentes à química do safrol, indicando que tal indústria poderia ter evoluído, bem como os aspectos econômicos e sociais que, ao lado da proibição do corte da canela-sassafrás, levaram em 1990 à extinção definitiva dessa "química fina que poderia ter sido". (shrink)

Dos diferentes fatores associados a uma mudança de paradigma e, portanto, a uma revolução química, o menos discutido é o que envolve os assim chamados experimentos exemplares, mudanças radicais na metodologia de trabalho e nos procedimentos empíricos da química, mudanças e modificações estas que, no caso de uma ciência natural empírica, podem ter como consequência dados experimentais antes inacessíveis, levando, por fim, a uma nova abordagem de conceitos, hipóteses e teorias e desencadeando uma "revolução" química, um novo paradigma. Muito mais (...) do que uma revolução química, dever-se-ia optar por uma gradativa evolução química. Escolhemos três dessas situações como "exemplares": a modificação no procedimento empírico da química pneumática, com o uso da cuba pneumática contendo mercúrio; a introdução de novos métodos de extração de compostos orgânicos naturais, com a substituição do método pirogênico pelo de extração com solventes; um novo entendimento de "análise química", com a substituição da comparação de amostras tidas como autênticas pela decomposição do analito. (shrink)

The chemist Max von Pettenkofer studied with Justus von Liebig, and after leaving Giessen in 1844 did not immediately find an academic position. During the period 1844/1845 he wrote a cycle of 16 Chemical Sonnets, but published them only in 1886. The Sonnets have with few exceptions a historiographical character. We present a translation of the Sonette into Portuguese as well as commentaries about their content and their philosophical significance. We also comment rather briefly on Pettenkofer’s career as an empirical (...) chemist and later as a somewhat heterodox hygienist. (shrink)

In this essay, we aim to provide an overview of the periodic table’s origins and history, and of the elements which conspired to make it chemistry’s most recognisable icon. We pay attention to Mendeleev’s role in the development of a system for organising the elements and chemical knowledge while facilitating the teaching of chemistry. We look at how the reception of the table in different chemical communities was dependent on the local scientific, cultural and political context, but argue that its (...) eventual universal acceptance is due to its unique ability to accommodate possessed knowledge while enabling novel predictions. Furthermore, we argue that its capacity to unify apparently disconnected phenomena under a simple framework facilitates our understanding of periodicity, making the table an icon of aesthetic value, and an object of philosophical inquiry. Finally, we briefly explore the table’s iconicity throughout its representations in pop art and science fiction. (shrink)

We set out a fundamental ontology of atomism in terms of matter points. While being most parsimonious, this ontology is able to match both classical and quantum mechanics, and it remains a viable option for any future theory of cosmology that goes beyond current quantum physics. The matter points are structurally individuated: all there is to them are the spatial relations in which they stand; neither a commitment to intrinsic properties nor to an absolute space is required. The spatial relations (...) change. All that is needed to capture change is a dynamical structure, namely dynamical relations as expressed in terms of the dynamical parameters of a physical theory. (shrink)

Over the past few years, the Virtual Organization (VO) paradigm has been emerging as an ideal solution to support collaboration among globally distributed entities (individuals and/or organizations). However, due to rapid technological and societal changes, there has also been an astonishing growth in technologies and services for mobile users. This has opened up new collaborative scenarios where the same participant can access the VO from different locations and mobility becomes a key issue for users and services. The nomadicity and mobility (...) introduces additional challenges for managing collaboration in VO environments. This paper focuses on the Identity Management challenge in a Mobile Dynamic VO environment, which is a VO that takes into account nomadicity and seamless mobility aspects as elaborated within the EU funded project Akogrimo (Access to Knowledge through the Grid in a mobile world). The resulting work is the design of the Akogrimo Identity Management system supporting the authentication and authorization process across the different administrative domains of the Mobile Dynamic VO. This design follows the service oriented approach and integrates the different perspectives: that of the network, that of the user and that of the service provider. Such an integration requires facing challenges; both from the architectural and technological viewpoints because different ‘worlds’ (i.e. network and service level) leverage different (and sometimes conflicting) approaches when addressing Identity Management. (shrink)

This paper elaborates on discussions in Germany regarding some of the ethical and legal issues in the area of the use and patenting of inventions involving human tissue. The issues discussed pertain to the benefits and problems regarding informed consent and the issue of property rights as they relate to the donation of cells and tissue.