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.

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)

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

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.