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.

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)

Falsification no longer is the cornerstone of philosophy of science; but it still looms widely that scientists ought to drop an explanatory hypothesis in view of negative results. We shall argue that, to the contrary, negative empirical results are unable to disqualify causally explanatory hypotheses—not because of the shielding effect of auxiliary assumptions but because of the fact that the causal irrelevance of a factor cannot empirically be established. This perspective is elaborated at a case study taken from the history (...) of plant physiology: the formaldehyde model of photosynthesis, which for about sixty years dominated the field—despite the fact that in these sixty years all the attempts to conclusively demonstrate even the presence of formaldehyde in plants failed. (shrink)

The information technological progress that has been achieved over the last decades has also given the humanities the opportunity to expand their methodological toolbox. This paper explores how recent advancements in natural language processing may be used for research in the history of ideas so as to overcome traditional scholarship's inevitably selective approach to historical sources. By employing two machine learning techniques whose potential for the analysis of conceptual continuities and innovations has never been considered before, we aim to determine (...) the extent to which they can enhance conventional research methods. It will amount to a critical evaluation of how the advantages of computational in-breadth analysis could be combined with the merits of traditional in-depth analysis in a philosophically fruitful way. After a brief technical description, the approach will be applied to an example: the conceptual (dis)continuity between medieval and early modern philosophy. All the challenges encountered during development and application will be carefully evaluated. We will then be able to assess whether these tools and techniques present promising extensions to the methodological toolbox of traditional scholarship, or whether they do not yet have the potential for a task as complex as the analysis of philosophical literature. The present investigation can thus be seen as an experiment on how far one can go with current machine-learning techniques in this area of research. In doing so, it provides important insights and guidance for future advances in the field. (shrink)

In his Geography, Ptolemy recorded the geographical coordinates of more than 6,300 toponyms of the known oikoumenē. This study presents the type of geographical information that was used by Ptolemy as well as the methods he applied to derive his geographical coordinates. A new methodological approach was developed in order to analyse the characteristic deviations of Ptolemy’s data from their reconstructed reference locations. The clusters of displacement vectors establish that Ptolemy did not obtain his coordinates from astronomical observations at each (...) geographical location. The characteristic displacement vectors reveal how Ptolemy derived the coordinates: he constructed locations on maps using a compass and ruler, for which he employed a small amount of astronomical reference data and geographical distance information; he made schematic drawings of coastlines, based on textual descriptions of coastal formations; and he situated additional locations within the established framework using reports of travel itineraries. (shrink)