DE / EN
2022/2023
International Conference on Large-Scale Experiments (Karlsruhe)
The final conference of the 6-year interdisciplinary research unit "Epistemology of the LHC" will take place in Karlsruhe (8-10 December 2022) and reflect on large-scale experiments from the perspectives of history, philosophy and social studies of science. More information can be found here: indico.uni-wuppertal.de/event/152/.
2021/2022
History and Philosophy of Physics Research Seminar (Summer)
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Time & Place: |
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Tuesdays from 16:15 to 17:45 CEST.
Almost all sessions can be attended via Zoom; the sessions that are indicated as 'hybrid' below may also be attended in person, in the main building (Am Hof 1, 53113 Bonn) in Lecture Room 1.070. Zoom-links and weekly reminders are announced via hpp@listen.uni-bonn.de. Subscribing to this list is possible a) here, b) by sending an empty email to hpp-subscribe@listen.uni-bonn.de, or c) by contacting nmartens@uni-bonn.de |
Conveners: |
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Dr. Juliusz Doboszewski & Dr. Niels Martens |
5 Apr 2022
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Ann C Thresher (UC San Diego & UniBonn)
Compact Spaces and Privileged Times; What the Video Game Asteroids Can Teach Us About Presentism Abstract
Presentism has long struggled with the results of special relativity. One proposed solution is to stipulate the existence of an ontologically or metaphysically privileged frame which defines the global present for all observers. Recently this proposal has cropped up in literature on spatially closed universes (SCUs) which seem to naturally instantiate such structures. This paper examines the privileged frame proposal through the lens of SCUs, arguing that even in these space-times which seem overwhelmingly friendly to presentism the theory face insurmountable challenges. It is then shown how these failures are fundamental to the project, rather than specific to the SCU case. |
12 Apr 2022
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Gábor Hofer-Szabó (Hungarian Academy of Sciences)
Two concepts of noncontextuality in quantum mechanics Abstract
There are two different and logically independent concepts of noncontextuality in quantum mechanics. First, an ontological (hidden variable) model for quantum mechanics is called noncontextual if every ontic (hidden) state determines the probability of the outcomes of every measurement independently of what other measurements are simultaneously performed. Second, an ontological model is noncontextual if any two measurements which are represented by the same self-adjoint operator, or equivalently, which have the same probability distribution of outcomes in every quantum state also have the same probability distribution of outcomes in every ontic state. In the talk I will argue that the Kochen-Specker arguments provide an algebraic (state-independent) proof only against noncontextual ontological models of the second type. |
19 Apr 2022
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Debate: Confirmation via Analogue Simulation
Radin Dardashti (University of Wuppertal) Grace Field (University of Cambridge) Niels Linnemann (University of Bremen) |
26 Apr 2022
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Roberto Lalli (Max Planck Institute for the History of Science, Berlin)
The Socio-Epistemic Networks for General Relativity, 1925-1970: The low-water mark, the renaissance, and the astrophysical turn Abstract
In the last years, a complex historical debate has emerged on the causes, origins, and manifestations of the process dubbed the ‘renaissance’ of Einstein’s theory of gravitation starting. After a thirty-year period of stagnation of the theory, known as its low-water-mark phase, the renaissance marks the return of general relativity to the mainstream of physics after the mid-1950s. The talk aims at presenting the main results of our analysis of the renaissance of general relativity based on the conceptual and methodological framework of socio-epistemic networks. This framework defines a three-layered taxonomy of knowledge networks: the social network (the collection of relations involving individuals and institutions), the semiotic network (the collection of the material representations of knowledge, e.g., citation networks), and the semantic network (the collection of knowledge elements and their relations, including concepts, topics, research agendas, or methods). On the basis of this multi-layer network analysis of the general relativity research landscape between 1925 and 1970, I will argue that the renaissance process should be understood as a two-step reconfiguration of research agendas resulting initially from the interplay of social and epistemic factors. A first phase of theoretical renaissance, driven by social transformations, occurred between the mid-1950s and the early 1960s, and transformed the general theory of relativity to a bona fide physical theory. The second phase of this process, which can be called the astrophysical turn, was an experiment-driven shift toward relativistic astrophysics and physical cosmology, and was strongly related to discoveries in the astrophysical domain in the 1960s. I will conclude by showing early results built on this approach to characterize the conceptual transformation characterizing the first phase as well as to capture the role played by the Brans-Dicke theory as catalyzer of research trends in the second phase of the astrophysical turn. |
3 May 2022
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Abstract
Scientific realists argue that empirically successful theories latch on to unobservable features of reality. But it is often thought that conventional theories of particle physics do not deserve realist commitment, despite their outstanding empirical success. Recently, a number of "effective" realisms have argued that we should distinguish between the low- and high-energy claims of particle theory and that we can and should be realist about the former but not the latter. I argue that this proposal conflicts with physical folklore, according to which the claims of realistic particle theories cannot be relativized to energy scales. I use this conflict to distinguish two forms of effective realism. One form of effective realism indeed conflicts with the kernel of truth in the physical folklore, making it inapplicable to the theories that enjoy empirical success. The second form of effective realism is compatible with realistic theories, but requires a substantial revision of the terms of the realist debate. I will indicate why I think the second form is nevertheless the more promising. |
10 May 2022 |
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No seminar
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17 May 2022
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Dialogue: Philosophy of the Historical Sciences
Paleontology, Geology & Archeology Adrian Currie (University of Exeter) Astronomy & Cosmology Juliusz Doboszewski (University of Bonn & BHI Harvard) |
24 May 2022
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Ettore Minguzzi (University of Florence)
A gravitational collapse singularity theorem consistent with black hole evaporation Abstract
The global hyperbolicity assumption present in gravitational collapse singularity theorems is in tension with the quantum mechanical phenomenon of black hole evaporation. In this talk I show that the causality conditions in Penrose's theorem can be almost completely removed. As a result, it is possible to infer the formation of spacetime singularities even in absence of predictability and hence compatibly with quantum field theory and black hole evaporation. |
31 May 2022
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Abstract
Our naïve human senses often detect phenomena that appear asymmetric in time when they are not. For example, a book will slide to a stop on a tabletop, and never the reverse. But, when that experience is carefully described in terms of dynamical systems, we find that the description invariably omits degrees of freedom in a way that hides an underlying temporal symmetry. This talk will develop an account of what is required to have a true arrow of time, in the sense that 'time itself' has an asymmetry. I will argue that most of what is commonly referred to as an ‘arrow of time’ fails to be a time asymmetry in this sense. |
BREAK (one week)
14 June 2022
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Jamee Elder (Black Hole Initiative, Harvard & UniBonn)
The "Direct Detection" of Gravitational Waves Abstract
In this talk, I will clarify and adjudicate a controversy that arose within the astrophysics community concerning whether or not the first LIGO detection, “GW150914”, was the first “direct detection” of gravitational waves. To do so, I provide an analysis according to which there is an epistemically significant distinction between direct and indirect detections in this context. Roughly, our justification for trusting a direct detection depends mainly on the reliability of instruments that are under our control, rather than on the reliability of our models of separate target systems. In contrast, indirect detections rely on confidence in such models. Having argued for this account of the direct/indirect distinction, I close by considering its application to LIGO’s other scientific role: observing black holes. This helps to illustrate some of the key epistemic challenges of gravitational-wave astrophysics (and indeed astrophysics broadly) in contrast to science with controlled experiments. (For those who are interested, the most recent version of the corresponding paper can be downloaded from the research section of my website.) |
21 June 2022
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Student Presentations (for members of UniBonn only; one talk in English, one in German)
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28 June 2022
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Abstract
Philosophers of science who engage with astrophysics often portray it as a distinctively observational science, since its targets are too distant to experiment upon. The lack of experiment in astrophysics is usually taken either (pessimistically) to imply that the field as a whole is epistemically handicapped, or (optimistically) to explain and justify the use of simulations in place of experiments in the pursuit of astrophysical knowledge. This characterization misses some fascinating features of the epistemology of laboratory astrophysics, which investigates the nature of celestial objects and processes using terrestrial experiments. Laboratory astrophysics provides an illuminating testbed for understanding the tradeoffs between experimental and observational methods that scientists face in practice. Drawing on a variety of cases—from axion searches to accelerator-based nuclear astrophysics to high-energy laser confinement experiments—I will argue that the subtleties of the epistemology of laboratory astrophysics are best appreciated by attending to the relationship between the research target and the causal production of the data. Ultimately, this framework actually illuminates more continuity between the epistemic situation in astrophysics and in other fields of empirical research than is often appreciated, in both the obstacles and the opportunities that arise. |
5 July 2022
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Abstract
Several philosophers have advocated an eliminativist position regarding gravitational energy and conservation principles applied to it. We cannot directly characterize the energy carried by the gravitational field with a local quantity analogous to what is used in other field theories: we cannot define a gravitational energy-momentum tensor that assigns local properties to spacetime points and can be integrated over volumes to characterize energy-momentum flows. Because of the equivalence principle, we can always choose a locally freely falling frame, and by so doing locally transform away the gravitational field. The eliminitavists take these features to imply that there is no such thing as ``gravitational energy'' or integral conservation laws governing it, and that efforts to resurrect such a notion illustrate how misleading it can be to treat general relativity as analogous to other field theories. In this talk I will consider how quasi-local definitions of energy and conservation laws based on them support a response to the eliminativists, and in particular concerns about whether such proposals depend on ``background structure'' in a problematic sense. Quasi-local energy and conservation laws depend on background structure --- we need a way to designate some motions as ``freely falling,'' so that energy-momentum transfers can be measured via departures from these trajectories. But I will argue that these background structures can justifiably be introduced within particular modeling contexts. The challenge regarding gravitational energy then has a different character: namely that there are many conflicting proposals for how to define quasi-local energy, and it is not clear whether they deliver consistent verdicts. |
12 July 2022
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Feraz Azhar (University of Notre Dame)
Flows into de Sitter from anisotropic initial conditions: An effective field theory approach Abstract
For decades, physicists have analyzed various versions of a "cosmic no-hair" conjecture, to understand under what conditions a spacetime that is initially spatially anisotropic and/or inhomogeneous will flow into an isotropic and homogeneous state. Wald's theorem, in particular, established that certain homogeneous but anisotropic spacetimes, if filled with a positive cosmological constant plus additional matter sources that satisfy specific energy conditions, will necessarily flow toward an (isotropic) de Sitter state at late times. In this talk, using an EFT-based dynamical framework, I'll describe recent work on the flow of homogeneous but anisotropic spacetimes toward (isotropic) de Sitter states under conditions more general than those to which Wald's theorem applies. In particular, in the absence of a bare cosmological constant, and for effective matter sources that do not obey the energy conditions required for Wald's theorem, the evolution of homogeneous but anisotropic spacetimes can be consistent with the emergence of an effective cosmological constant. |
Global Structure in Semi-Classical Gravity Conference (Munich)
21-23.07.2022, LMU Munich. This will be the first major conference to address foundational issues associated with semi-classical gravity. See here for more information: https://www.mcmp.philosophie.uni-muenchen.de/events/workshops/container/scg2022/index.html
Persistence in Stability Workshop
In collaboration with the Change & Change-Makers DFG-Network, the Lichtenberg Group is organising a workshop on persistence in stability. See here for further info.
History, Philosophy & Sociology of Cosmology & Astroparticle Physics Conference
HPS-CAP conference, 29-30 June 2022, University Club Bonn. Organised by the project "LHC, dark matter & gravity" of the research unit "Epistemology of the LHC". See here for further info.
Beyond Models Workshop
Beyond Models Workshop, 14-15 June 2022, University of Bonn. Organised by the project "Model Building and Dynamics" of the research unit "Epistemology of the LHC". See here for further info.
AGPhil DPG Conference
Section of the Philosophy of Physics Group during the German Physical Society Conference, 21-25 March 2022, online/Heidelberg. Organised by Dennis Lehmkuhl & Radin Dardashti. For further info, see here.
Philosophy of Primordial Black Holes as Dark Matter Candidates Reading Group (PPBHDM)
Primordial black holes as dark matter research program connects to large-scale cosmic history in the very early universe as well as quantum gravity phenomenology. Despite lack of evidence for the existence of primordial black holes, PBHDM have been intensively pursued for over 50 years. This makes it a striking territory for philosophers of physics to explore. The group meets on Wednesdays, from 17:00 till 18:00 CE(S)T, every two weeks (alternating with the Particle/Astro/Cosmology Discussion Group). For more information, contact Juliusz Doboszewski or Mike Schneider.
Particle/Astro/Cosmology Discussion Group
After the online philosophy of dark matter workshop in March 2021, a group of roughly 20 scholars (incl. physicists, philosophers, historians & sociologists) started a regular, global, online discussion group on the history, philosophy and sociology of the intersection between cosmology, astronomy and particle physics, with an initial focus on dark matter. We meet every two weeks on Wednesdays, from 17:00 till 18:00 CE(S)T. Initially we discussed the dark matter chapters from Peebles’ recent book “Cosmology’s Century”, but currently we discuss whatever other/broader topics are of interest to the group, either based on a published paper, a draft by a group member, or we just have an open discussion about a specific theme. If you are interested in joining the "Peebles Fan Club", please contact nmartens [at] uni-bonn.de.
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Date |
Topic |
Reading |
1 |
21 April 2021 |
Intro |
Peebles Ch.1 |
2 |
5 May 2021 |
Dark Matter |
Peebles Ch.6.1-3 |
3 |
19 May 2021 |
Dark Matter |
Peebles Ch.6.4-6 |
4 |
2 June 2021 |
Dark Matter |
Peebles Ch.7 |
5 |
30 June 2021 |
Interaction bewteen particle physics, astronomy & cosmology (constraints & communities) |
None. General discussion. |
6 |
14 July 2021 |
Early history of dark matter & cosmology |
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7 |
29 Sept 2021 |
Cosmic structure |
Peebles Ch5.1 |
8 |
13 Oct 2021 |
Relationship between philosophy/history/sociology and cosmology/astronomy/particle physics |
None. General discussion. |
9 |
3 Nov 2021 |
Testability in modern cosmology |
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10 |
17 Nov 2021 |
Cosmological Principle |
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11 |
1 Dec 2021 |
Historical style in modern cosmology |
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12 |
15 Dec 2021 |
Simulation in astronomy & cosmology |
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13 |
19 Jan 2022 |
Experiment vs Observation |
None. Small presentation followed by general discussion. |
14 |
2 Feb 2022 |
Stabs in the Dark Sector |
Schneider draft |
15 |
16 Feb 2022 |
Cosmological Realism |
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16 |
9 March 2022 |
Manchak on underdetermination in cosmology |
Manchak 2009, 2011 |
17 |
23 March 2022 |
The fate of TeVeS |
History, Philosophy & Sociology of Large Physics Experiments Spring School (Wuppertal)
History and Philosophy of Physics Research Seminar (Winter)
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