Quality assurance in large terminologies is a difficult issue. We present two algorithms that can help terminology developers and users to identify potential mistakes. We demon­strate the methodology by outlining the different types of mistakes that are found when the algorithms are applied to SNOMED-CT. On the basis of the results, we argue that both formal logical and linguistic tools should be used in the development and quality-assurance process of large terminologies.

We present the details of a methodology for quality assurance in large medical terminologies and describe three algorithms that can help terminology developers and users to identify potential mistakes. The methodology is based in part on linguistic criteria and in part on logical and ontological principles governing sound classifications. We conclude by outlining the results of applying the methodology in the form of a taxonomy different types of errors and potential errors detected in SNOMED-CT.

In South Africa scholars in the broad field of practical theology are currently faced with a daunting challenge: to rethink the reconciling role of the institutional church in the light of continued challenges facing reconciliation within post-apartheid and post-Truth and Reconciliation Commission (TRC) South Africa. This contribution investigates whether the transdisciplinary, region-centred scientific research approach with a focus on the Hölderlin perspective on reconciliation could assist scholars in practical theology to address reconciliation in a post-apartheid and post-TRC society. The article (...) proposes a contextual and constructive approach to reconciliation in order to assist South African scholars in the field of practical theology and the institutional church to address the challenges of reconciliation in a postapartheid and post-TRC society. The contribution confirms that this approach does indeed assist the field of practical theology to contribute to reconciliation without the risk of speaking a language that nobody beyond theology can understand. (shrink)

Within contemporary health care, many of the decisions affecting the health and well-being of patients are not being made by the clinicians or health professionals, but by those involved in health care management. Existing literature on organizational ethics provides insight into the various structures, processes and strategies - such as mission statement, ethics committees, ethical rounds … - that exist to create an organizational climate, which fosters ethical practices and decision-making It does not, however, show how health care managers experience (...) their job as being intrinsically ethical in itself. In the present article, we investigate the way in which ethical values are present in the lived experiences and daily practice of health care management. What does it imply to take up a managing position within a health care institution and to try to do this in an ethically inspired way? We carried out a qualitative study (Grounded Theory Approach) to explore the essence of values-based leadership in health care. We interviewed 15 people with extensive experience in health care management in the fields of elderly care, hospital care and mental health care in the various regions of Flanders, Belgium. Six predominant themes, presented as metaphors, illustrate the essence of values-based leadership in health care management. These are: (1) values-based health care management as managing a large garden, (2) as learning and using a foreign language, (3) going on a trekking with an ethical compass, (4) embodying integrity and authenticity in a credible encounter with everyone, (5) being a present and trustworthy leader during sun and storm, and (6) contributing to human flourishing by giving people wings to fly. Notwithstanding the importance of organizing a good ethics infrastructure, values-based leadership in health care entails much more than that. It is about the co-creation of an integrated and comprehensive ethical climate of which community-model thinking and authentic leadership are essential components. As a never-ending process, the six metaphors can help leaders to take substantive proactive steps to shape a fruitful ethical climate within their organization. (shrink)

Given the purpose of this special edition, to consider theologically the implications of the Fourth Industrial Revolution, in this contribution, the writings of one of the important yet under-appreciated South African figures in thinking from biblical theology on matters of economics, Klaus Nürnberger, are taken into review. The relationship between (1) biblical witness and (2) faith and (3) deeds stands central in Nürnberger’s theological framework. His interdisciplinarity has lasting validity because he takes seriously the disciplines involved, such as historical Bible (...) scholarship, economic theory, social theory and the like. By his own reckoning, it is partly because of this kind of interdisciplinarity that Nürnberger’s contributions on this topic had in a sense been marginalised. For this reason too, it is important in a new era to review sympathetically and appropriate critically the significant contributions of Nürnberger on the biblical witness to economic engagement. Contribution: This research article, as a part of this themed collection, considers theologically the implications of the Fourth Industrial Revolution with a review of Nürnberger’s contributions on the biblical witness to economic engagement. Nürnberger’s interdisciplinarity in his contributions helps set the direction for future engagements in the dawning post-secular era. (shrink)

Given the purpose of this special edition, to consider theologically the implications of the Fourth Industrial Revolution, in this contribution, the writings of one of the important yet under-appreciated South African figures in thinking from biblical theology on matters of economics, Klaus Nürnberger, are taken into review. The relationship between (1) biblical witness and (2) faith and (3) deeds stands central in Nürnberger’s theological framework. His interdisciplinarity has lasting validity because he takes seriously the disciplines involved, such as historical Bible (...) scholarship, economic theory, social theory and the like. By his own reckoning, it is partly because of this kind of interdisciplinarity that Nürnberger’s contributions on this topic had in a sense been marginalised. For this reason too, it is important in a new era to review sympathetically and appropriate critically the significant contributions of Nürnberger on the biblical witness to economic engagement. Contribution: This research article, as a part of this themed collection, considers theologically the implications of the Fourth Industrial Revolution with a review of Nürnberger’s contributions on the biblical witness to economic engagement. Nürnberger’s interdisciplinarity in his contributions helps set the direction for future engagements in the dawning post-secular era. (shrink)

In this contribution, the mystagogic engagement with Bible texts is considered. Good and bad reasons for drawing on the Bible are considered, both within personal and cultural frameworks. Different exegetical procedures are taken into review to inform a discussion of particularly the mystagogic engagement with the text. The latter is characterised by seeking faith from the biblical texts. For theological reasons, historical exegesis is proposed as particularly suited to mystagogic facilitation. Contribution: There are good and bad reasons for drawing on (...) the Bible, within personal and cultural frameworks. Different exegetical procedures inform a discussion of mystagogic engagement with the text, seeking faith from the biblical texts. Historical exegesis is proposed as particularly suited to mystagogic facilitation. (shrink)

In pre-democratic – also pre-modern – times, religion had been at the centre of much of human life, filling the private as well as the public realm of people’s daily existence. However, with the change to democratic rule in major countries in the modern world (see, most influentially, Article 1 of the French Constitution after the French Revolution and the First Amendment to the Constitution of the United States, influencing all other democracies in their wake), religion has for the most (...) part reflexively been sidelined from public life. Or has it? Does religion not still hold a special place in law in democratic societies, but now in reverse? Firstly, whereas matters of religious faith had throughout the greater part of human history been included in matters of politics, it is now as a matter of course of law excluded, purposely so. Religion is thus still a ‘special case’, a unique aspect of humanity when compared to all other matters, in law as much as in politics and other aspects of public life. Secondly, in the post-secular cultural climate dawning across the world, matters of faith (religion, spirituality) are no longer as stringently excluded from public life, which impacts directly on how religion is touched upon in law, sociology, philosophy, music and other academic disciplines too. Our dawning post-secular age is bringing something new. Two scholars, who have been doing foundational work in this regard, have done so fully in parallel, not taking cognisance of the mutualities in their academic contributions. Otto in Munich, Germany, has been combining his two areas of expertise, the Pentateuch in the Hebrew Bible and the sociologist Max Weber, to indicate the trajectory through history of democratic impulses from Ancient Near Eastern founding documents into the current era. Benson in Sydney, Australia, has on his part been drawing on his expertise in law as practised in Canada and taught in Europe, South Africa and Australia to indicate how, in inclusively liberal democracies, law cannot justifiably be used to exclude religion from the public domain, as has been the usual modern case. Drawing together these parallel contributions, Lombaard places these initiatives within the emerging post-secular climate, which augurs a different way of being religious or non-religious, publicly as much as privately, in democratic societies in our time. (shrink)

This contribution is part of a series on Methodology and Biblical Spirituality. In this, the fourth contribution, the scope is widened; more practical-analytically oriented, three thoroughly different but nevertheless all unusual kinds of interpretations of the Bible are described, characterised and contextualised. Namely:• In order to explain what are perceived as textual anomalies, some Old Testament authors have been described by US-based medical practitioners as having suffered psychiatric dysfunctions.• The Garden of Eden from Genesis 2 and further has been located (...) by a recently diseased Nigerian scholar as having been in her home country, with a Nigerian race having been the predecessors of biblical Adam and Eve.• Rastafarians, primarily Jamaica-based, regard marijuana as a holy herb and find direct support for their religious use of this plant in the Bible.However strange such ‘mystifying’ interpretations may seem within the theological mainstreams of Judeo-Christianity, there is more to these kinds of interpretations than simple whim. Certain cultural conditions along with personal, particularly spiritual, commitments enable these interpretations, which must be taken seriously in order to come to a fuller understanding of the text–interpreter dynamic. These then can cast at least some form of reflective light on the more usual current biblical-interpretative mainstreams within Judeo-Christianity, posing in a new light the question of what constitutes legitimate interpretations, also within mainstream interpretations, as religiously inclined people try to live their lives in the light of Scripture. (shrink)

Since its inception in 1988, the SAREprogram has sponsored hundreds of projects to exploreand apply economically viable, environmentally sound,and socially acceptable farming systems. Recognizingthat researchers often collaborated with producers andthat producer interest in sustainable agriculture wasincreasing, SARE's North-Central Region began directlyfunding farmers and ranchers in 1992 to test their ownideas on sustainable agriculture. The present articleis based on data from the formative evaluation of thefirst five years (1992 to 1996) of the NCR-SAREProducer Grant Program. The evaluation used acombination of mail (...) surveys, non-response telephoneinterviews, and personal interviews.The evaluation revealed that the Program hassucceeded in showing that sustainable agriculturaltechnologies and practices can be viable andprofitable alternatives to conventional ways ofproducing crops and animals while simultaneously beingless environmentally damaging. On the other hand, thecontributions of the Producer Grant Program to thesocial and institutional spheres in which agricultureis embedded are less clear. Changes in these spheresare imperative for the success of sustainableagriculture, and for it to become more mainstream.Such changes cannot occur overnight, but they willremain the main challenge for SARE to tackle in thenear future. (shrink)

Au travers de la multiplicité des usages du field recording, tantôt support d’étude des paysages sonores, tantôt outil de composition musical et environnemental, mais nécessairement dépendant d’un contexte (inter) culturel, David Christoffel et Guillaume Tiger explorent un certain rapport à la nature. Comment parle-t-on de nature via les field recordings? Quel sens donner à la représentation de la nature dans la musique? Comment « justice » est-elle rendue à la nature dans l’élaboration de paysages sonores virtuels? Les réflexions croisées (...) des auteurs sur ces questionnements tournent en sens inverses autour d’un même pot de sons naturels. (shrink)

« Un coworking sans communauté n’existe pas. » Qu’est-ce qui sépare les nous du tiers-lieu de ceux de la start-up (plus ou moins nationalisée)? Qu’est-ce qui distingue les bretelles (d’un nous relativement dilaté, diffracté ou bifurquant) des autoroutes (du je au cœur du développement personnel comme du nous des team buildings et atelier de we design)? L’auto-affectation d’un soi mis au pluriel tente, par un simple jeu pronominal, de cacher son intention de relier tout le monde. À travers les reflets (...) de ces belles âmes dans leurs variations esthétiques, cet article se propose de penser les réactualisations de la standardisation psychique mondiale en montrant comme elles brouillent de quel entre-nous ça parle. On part d’une série de citations des stars de la république des lettres. Direct, on multiplie les formes de déterritorialisations énonciatives comme autant de traversées d’un nous attaché à son incertitude d’échelle et excité par ses anachronismes : expérience originelle de l’autre comme soi, atelier alter-constructiviste, méditation auto-décentrante, réunion anti-facilitatrice, contre-point sur la situation actuelle. (shrink)

Dit boek biedt een kritische inleiding in de godsdienstfilosofie, aan de hand van een confrontatie tussen enerzijds G.W.F. Hegels filosofie van de monotheïstische religies en anderzijds godsdienstwetenschappelijke inzichten in en vanuit de godsdiensten zelf. Het doel is te komen tot een wijsgerige verheldering van wat deze religies kenmerkt. Wat kan een filosofische benadering van de verschillende godsdiensten, zoals die van Hegel, bijdragen aan een beter begrip ervan? Hoe zou de godsdienstfilosofie een rol kunnen spelen in het actuele debat over religie, (...) en de verhouding daarvan tot de grondslagen van recht en politiek? De manier waarop we over God denken en dus hoe we geloven, beïnvloedt onze moraal en ons recht, de wetten die we maken en de wijze waarop we die toepassen. Hegel had veel op met het christendom. In zijn ogen vormde het christelijk geloof ten opzichte van andere, eerdere godsdiensten een vervolmaking en een voltooiing van de religie. Filosofisch bezien is het christendom de religie van vrijheid en van verzoening van God en de mens met elkaar. Alle godsdiensten die voorafgingen aan het christendom, beschouwt hij als beperkter en eenzijdiger: de ‘ware geest’ is daarin nog onvoldoende ontwikkeld. Deze hoogst controversiële claim wordt in dit boek aan een nader, kritisch onderzoek onderworpen. (shrink)

Since its inception in 1988, the SAREprogram has sponsored hundreds of projects to exploreand apply economically viable, environmentally sound,and socially acceptable farming systems. Recognizingthat researchers often collaborated with producers andthat producer interest in sustainable agriculture wasincreasing, SARE's North-Central Region began directlyfunding farmers and ranchers in 1992 to test their ownideas on sustainable agriculture. The present articleis based on data from the formative evaluation of thefirst five years (1992 to 1996) of the NCR-SAREProducer Grant Program. The evaluation used acombination of mail (...) surveys, non-response telephoneinterviews, and personal interviews.The evaluation revealed that the Program hassucceeded in showing that sustainable agriculturaltechnologies and practices can be viable andprofitable alternatives to conventional ways ofproducing crops and animals while simultaneously beingless environmentally damaging. On the other hand, thecontributions of the Producer Grant Program to thesocial and institutional spheres in which agricultureis embedded are less clear. Changes in these spheresare imperative for the success of sustainableagriculture, and for it to become more mainstream.Such changes cannot occur overnight, but they willremain the main challenge for SARE to tackle in thenear future. (shrink)

Taking a new look at the language of ‘religious experience’, the authors in this contribution take into review this aspect in the current theological discussion, and in the church pew, asking the question: Does George Lindbeck’s criticism of the experiential-expressive model of religion still have something to say to us? Firstly, Lindbeck is reviewed and recouped. Then, religious experience and its commodification are discussed, at the hand also of the heritage from Schleiermacher onwards on experience. Taking a position within the (...) post-modern, relativist, critical realist and pragmatist possibilities, a community-embedded sense of truth is concluded to without sacrificing the possibility of universalising claims. Is it possible, though, within the cultural reflex towards psychologised faith to retain a historically oriented depth? (shrink)

The chapters in this book offer an in-depth and profound overview of Hegel’s daring, many-faceted philosophical interpretations of the multifarious and dialectically interrelated, historical religions, including the Islam and the ...

Religion is increasingly a social and political factor in post-modern societies nowadays and the question of the role of religion in the public sphere is more and more brought to the fore: a challenge to legal philosophers. Should religion be only a private affair, or should the public dimension of religion be more acknowledged? Do we have to interpret the freedom of religion and the separation of church and state in a strict (laicist) sense, or do we have to allow (...) for a more benevolent relation between religion and the state? This collection of essays explores these questions in various and new ways. (shrink)

Exploring the pre-political en pre-legal spiritual infrastructure from which modern, liberal democracies in the West live, but cannot guarantee, this book ...

Based on two presentations during a February 2020 South African academic visit at the University of Pretoria and the University of Johannesburg, in this contribution, the authors of this article engage with one of the bestselling recent volumes in philosophy, Martin Hägglund’s This Life: Why Mortality Makes Us Free (here, the 2020 edition; initial publication date, 2019). In this book, Hägglund propagates ideas akin to those promoted within secular humanism. Whilst on the one hand this article elaborates the shortcomings of (...) Hägglund’s criticism of religion, on the other hand it also strives for an empathetic reading of his secular humanist philosophy. The authors place this conversation within the post-secular religio-cultural climate currently rising internationally, along with some further contextualising remarks. The most important part of this article is the last section (‘Pitting some theological voices…’) in which the authors engage Hägglund’s main arguments theologically, which elaborate on the finitude of human life all the whilst denying it a prospect of immortality. The debate in this section procceeds along the lines of religious thought of Emmanuel Falque, Ebenhard Jüngel and Dewi Zephania Phillips, with a view to reconcile the radical awareness of finitude and temporality of human life, characteristic for modern discourse(s), with the religious language practices sustaining belief in eternal life. Contribution: This article engages with how Martin Hägglund’s This Life: Why Mortality Makes Us Free does not fairly convey aspects of the sense of secularism, and can additionally on the senses of finitude and temporality be improved by insights from Emmanuel Falque, Ebenhard Jüngel and Dewi Zephania Phillips. (shrink)

In this contribution, the authors describe the theological contribution of Don Cupitt, initially in stronger relation to Jacques Derrida and also contextualising his insights through the work of some of his predecessors, contemporaries and those who write in his wake; also, in relation to his times and the trends on which he reacts. The latter is also transposed to some currently unfolding theological, ecclesial and societal trends internationally. The main emphases on Cupitt highlighted here may well, different to what initial (...) reactions might be, be of value for certain groups of Christian believers. (shrink)

Agricultural development strategies to date were chiefly based on Western technological solutions, with mixed success rates. Farming Systems Research (FSR) was advanced as a way to increase the use of indigenous knowledge of farming to make new technologies more adaptable and appropriate to farming conditions. FSR has enabled researchers to focus attention on people and their knowledge by increasing people's participation in problem identification and new technology validation. In practice, though, FSR continues to be a top-down approach: technologies continue to (...) be developed (in most cases) in the exogenous, Western knowledge system. Little has been done to develop indigenous technology generating and diffusing capacities already present in the rural areas. In this paper, a model adapted from Bell (1979) will be advanced that is based on cooperation and collaboration between the exogenous and indigenous knowledge systems leading to a synthesis of the two. The underlying principle of the model is that the ultimate solution for rural development is not the dumping of more scientists upon rural people (of whatever discipline) to make exogenously-generated technologies more adaptable and in-line with people's problems, but to strengthen, empower, and legitimize indigenous capacities for identifying problems and developing solutions for these problems. The “empowerment” of the indigenous knowledge/technology system (however difficult that may be politically) so that it has equal footing with Western knowledge may well be the most important step in a strategy of enabling the people in the developing countries themselves to alleviate their poverty. (shrink)

This paper attempts to show how the logical empiricists’ interpretation of the relation between geometry and reality emerges from a “collision” of mathematical traditions. Considering Riemann’s work as the initiator of a 19th century geometrical tradition, whose main protagonists were Helmholtz and Poincaré, the logical empiricists neglected the fact that Riemann’s revolutionary insight flourished instead in a non-geometrical tradition dominated by the works of Christoffel and Ricci-Curbastro roughly in the same years. I will argue that, in the attempt to (...) interpret general relativity as the last link of the chain Riemann–Helmholtz–Poincaré–Einstein, logical empiricists were led to argue that Einstein’s theory of gravitation mainly raised a problem of mathematical under-determination, i.e. the discovery that there are physical differences that cannot be expressed in the relevant mathematical structure of the theory. However, a historical reconstruction of the alternative Riemann–Christoffel–Ricci–Einstein line of evolution shows on the contrary that the main philosophical issue raised by Einstein’s theory was instead that of mathematical over-determination, i.e. the recognition of the presence of redundant mathematical differences that do not have any correspondence in physical reality. (shrink)

In a previous study the author proposed that the second edition of Leviathan arose from an abortive attempt to print the text in London in 1670, and consisted partly of sheets salvaged from that attempt, and partly of new sheets printed in Amsterdam later in the 1670s. This article defends and amplifies that account of the printing. It responds to the alternative account presented by the late Karl Schuhmann, noting some problematic features of his theory; it considers the evidence of (...) misprints and typographical changes in the Bear; it offers an analysis of the skeleton formes, which, combined with the evidence of misprints, confirms the scenario previously presented; and it also presents some new external evidence which helps to identify the publishers of the Bear edition. (shrink)

The Schwarzschild solution (Schwarzschild, 1915/16) to Einstein’s General Theory of Relativity (GTR) is accepted in theoretical physics as the unique solution to GTR for a central-mass system. In this paper I propose an alternative solution to GTR, and argue it is both logically consistent and empirically realistic as a theory of gravity. This solution is here called K-gravity. The introduction explains the basic concept. The central sections go through the technical detail, defining the basic solution for the geometric tensor, the (...) Christoffel symbols, Ricci tensor, Ricci scalar, Einstein tensor, stress-energy tensor and density-pressure for the system. The density is integrated, and some consistency properties are demonstrated. A notable feature is the disappearance of the event horizon singularity, i.e. there are no black holes. So far this is for a single central mass. A generalization of the solution for multiple masses is then proposed. This is required to support K-gravity as a viable general interpretation of gravity. Then the question of empirical tests is discussed. It is argued that current observational data is almost but not quite sufficient to verify or falsify K-gravity. The Pioneer spacecraft trajectory data is of particular interest, as this is capable of providing a test; but the data (which originally showed anomalies that match K-gravity) is now uncertain. A new and very practical experiment is proposed to settle the matter. This would provide a novel test of GTR, and a novel test of the cause of the Pioneer anomalies. In conclusion, K-gravity has extensive ramifications for gravitational physics and for the philosophy of GTR and space-time. (shrink)

This paper, which is mainly based on unpublished material, focuses on the scientific influence that Felice Casorati exerted on Salvatore Pincherle. This influence can be traced, in particular, in Casorati’s work on the finite-difference calculus as conceived and published between 1879 and 1880 when Pincherle was living in Pavia. Casorati’s work has an interesting back story related to his entry to the 1880 Grand Prix of the French Académie des Sciences that helps us in understanding Casorati’s personality. Moreover, the correspondence (...) that Casorati exchanged with other mathematicians on his work reveals that some of the results contained in Casorati :10–45, 1880b) had been obtained—though in a narrower context—in an early paper by Christoffel. Finally, the letters between Casorati and Pincherle contain a short unpublished note by Pincherle on a paper by Jules Tannery :113–182, 1875). This note offers the first evidence of the influence of Casorati :10–45, 1880b) on Pincherle’s work on the finite-difference calculus. (shrink)

The generally covariant Lagrangian densityG = ℛ + 2K ℒmatter of the Hamiltonian principle in general relativity, formulated by Einstein and Hilbert, can be interpreted as a functional of the potentialsg ikand φ of the gravitational and matter fields. In this general relativistic interpretation, the Riemann-Christoffel form Γ kl i = kl i for the coefficients г kl i of the affine connections is postulated a priori. Alternatively, we can interpret the LagrangianG as a functional of φ, gik, and (...) the coefficients г kl i . Then the г kl i are determined by the Palatini equations. From these equations and from the symmetry г kl i = г lk i for all matter fields with δℒ/δΓ=0 the Christoffel symbols again result. However, for Dirac's bispinor fields, δℒ/δΓ becomes dependent on the Dirac current, essentially with a coupling factor ∼Khc. In this case, the Palatini equations define a new transport rule for the spinor fields, according to which a second universal interaction results for the Dirac spinors, besides Einstein's gravitation. The generally covariant Dirac wave equations become the general relativistic nonlinear Heisenberg wave equations, and the second universal interaction is given by a Fermi-like interaction term of the V-A type. The geometrically induced Fermi constant is, however, very small and of the order 10−81erg cm3. (shrink)

A geometric interpretation of gravitation is given using general relativity. The law of gravitation is taken in the formR 44=0, whereR 44is the component of the contracted Riemann-Christoffel (Ricci) tensor representing the curvature of time. The remaining curvature components of the contracted Riemann-Christoffel tensor may or may not vanish. All that is required in addition toR 44=0 is that the Gaussian curvatureR be nowhere infinite. The conditionR 44=0 yields a nonlinear wave equation. One of the static degenerate solutions (...) represents the gravitational field surrounding a static gravitational point singularity. It is found that for this solution, the three famous predictions of general relativity are obtained in the weak-field approximation. In addition, it is found that there is a correction to the Kepler period of revolution for an orbit. (shrink)

Aus dem Inhalt: J. Rupke, Religion und Wissenschaft - religionswissenschaftliche PerspektivenR. Elior, Enoch Son of Jared and the Solar Calendar of the Priesthood in QumranM. Fishbane, The Song of Songs and Ancient Jewish Religiosity: Between Eros and HistoryR. Goetschel, Les trois piliers du monde d'apres le Maharal de PragueW. Frey, Ein geborner Jud von Jerusalem. Uberlegungen zur Entstehung der Ahasver-FigurD. Krochmalnik, Kynisches in der rabbinischen LiteraturM. Voigts, Unterirdisch - oberirdisch. Verstreute Gedanken zu einem verbreiteten ToposH.O. Horch, Die Neugier des Satirikers. (...) Zum Judenbild des Hans Jacob Christoffel von GrimmelshausenS. Gilman, A Dream of Jewishness on the Frontier: Kafka's Tumor and "The Country Doctor"u.v.a. (shrink)

We describe our explicit Lorentz-invariant solution of the Einstein and null geodesic equations for the deflection experiment of 2002 September 8 when a massive moving body, Jupiter, passed within 3.7’ of a line-of-sight to a distant quasar. We develop a general relativistic framework which shows that our measurement of the retarded position of a moving light-ray deflecting body (Jupiter) by making use of the gravitational time delay of quasar’s radio wave is equivalent to comparison of the relativistic laws of the (...) Lorentz transformation for gravity and light. Because, according to Einstein, the Lorentz transformation of gravity field variables must depend on a fundamental speed c, its measurement through the retarded position of Jupiter in the gravitational time delay allows us to study the causal nature of gravity and to set an upper limit on the speed of propagation of gravity in the near zone of the solar system as contrasted to the speed of the radio waves. In particular, the v/c term beyond of the standard Einstein’s deflection, which we measured to 20% accuracy, is associated with the aberration of the null direction of the gravity force (“aberration of gravity”) caused by the Lorentz transformation of the Christoffel symbols from the static frame of Jupiter to the moving frame of observer. General relativistic formulation of the experiment identifies the aberration of gravity with the retardation of gravity because the speed of gravitational waves in Einstein’s theory is equal to the speed of propagation of the gravity force. We discuss the misconceptions which have inhibited the acceptance of this interpretation of the experiment. We also comment on other interpretations of this experiment by Asada, Will, Samuel, Pascual–Sánchez, and Carlip and show that their “speed of light” interpretations confuse the Lorentz transformation for gravity with that for light, and the fundamental speed of gravity with the physical speed of light from the quasar. For this reason, the “speed of light” interpretations are not entirely consistent with a retarded Liénard–Wiechert solution of the Einstein equations, and do not properly incorporate how the phase of the radio waves from the quasar is perturbed by the retarded gravitational field of Jupiter. Although all of the formulations predict the same deflection to the order of v/c, our formulation shows that the underlying cause of this deflection term is associated with the aberration of gravity and not of light, and that the interpretations predict different deflections at higher orders of v/c beyond the Shapiro delay, thus, making their measurement highly desirable for deeper testing of general relativity in future astrometric experiments like Gaia, SIM, and SKA. (shrink)

This paper attempts to explain the emergence of the logical empiricist philosophy of space and time as a collision of mathematical traditions. The historical development of the ``Riemannian'' and ``Helmholtzian'' traditions in 19th century mathematics is investigated. Whereas Helmholtz's insistence on rigid bodies in geometry was developed group theoretically by Lie and philosophically by Poincaré, Riemann's Habilitationsvotrag triggered Christoffel's and Lipschitz's work on quadratic differential forms, paving the way to Ricci's absolute differential calculus. The transition from special to general (...) relativity is briefly sketched as a process of escaping from the Helmholtzian tradition and entering the Riemannian one. Early logical empiricist conventionalism, it is argued, emerges as the failed attempt to interpret Einstein's reflections on rods and clocks in general relativity through the conceptual resources of the Helmholtzian tradition. Einstein's epistemology of geometry should, in spite of his rhetorical appeal to Helmholtz and Poincaré, be understood in the wake the Riemannian tradition and of its aftermath in the work of Levi-Civita, Weyl, Eddington, and others. (shrink)