UPAC Colloquium
The weekly, hybrid UPAC colloquium on the philosophy of astronomy, astro(particle)physics and cosmology takes place on Tuesdays (unless there is a Descartes Colloquium) and rotates between the following formats:
| # | Format | Time | Online? |
|---|---|---|---|
| 1 | Research presentation by (external) speaker | 15:30-17:00 CE(S)T | Hybrid |
| 2 | Reading group | 16:00-17:00 CE(S)T | Hybrid |
| Pre-existing Descartes colloquium on history & philosophy of science | 15:30-17:00 CE(S)T | Hybrid (email dc-colloquium@uu.nl for link) | |
| 3 | Work-in-progress session (WiP) | 16:00-17:00 CE(S)T | Hybrid |
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Main organiser: Sanne Vergouwen. Co-organiser: Antonio Ferreiro
Schedule 2024-2025
Location for UPAC Colloquium: Buys Ballot Building (unless indicated otherwise) - or online (Teams link will be sent via mailing list; see above for sign-up).
| Title | Experimentation in cosmology: Intervening on the whole universe |
| Author | Gauvain Leconte-Chevillard [Namur University] |
| Location | Buys Ballotgebouw - Room BBG 3.45 |
| Time | 16:00-17:00 |
| Abstract | There are many arguments against the possibility of experimenting on the whole universe. This system seems to be too big to be manipulated, it exists in only one exemplar and its evolution is a non-repeatable process. In this paper, I claim that we can nonetheless talk about experimentation in cosmology if we use Woodward’s non-anthropocentric notion of intervention. However, Woodward and other interventionists argued that an intervention was necessarily an exogenous causal process and thus that no intervention on a closed system such as the universe was possible. I discuss their argument and I determine the conditions under which a consistent notion of endogenous intervention on the universe can be defined. Then, I show that there is at least one cosmic phenomenon satisfying these conditions: the photon decoupling. Finally, I draw some conclusions from this analysis regarding a realist approach of cosmology. |
| Title | Antimatter and Standard Cosmology: Historical and Modern Perspectives |
| Speaker | Helge Kragh [Aarhus University] |
| Location | Buys Ballotgebouw - Room BBG 3.45 |
| Time | 15:30-17:00 |
| Dinner | If you would like to join the speaker for dinner downtown, please let us know the day beforehand via cosmo-master.assistant@uu.nl. |
| Abstract | The standard (ΛCDM) cosmological model faces a number of problems, which has made some critics to conclude that it is in a state of crisis and in need of a new paradigm. Among these much-discussed problems are dark matter, the magnitude of dark energy, the so-called Hubble tension, early galaxy formation, the cosmological principle, and more. There is another problem, much older but less discussed, namely the glaring asymmetry between matter and antimatter. (The comprehensive volume The Philosophy of Cosmology from 2017 doesn’t even mention antimatter.) My presentation will focus on the antimatter problem in its historical as well as modern contexts of astronomy and cosmology. The origin of the problem can be traced back to P. Dirac (1933), and some of the early highlights were due to M. Goldhaber (1956) and A. Sakharov (1967). More recently, several speculative hypotheses involving a separate or earlier antimatter universe have been proposed. Although there are, and for half a century have been, numerous proposals of solving or circumventing the cosmological antimatter problem, none of them have won general acceptance. They all presuppose some ‘new physics’ or fail to reproduce the successes of the standard model. Thus, still today it remains a mystery why antimatter is almost completely absent in the observed universe. |
| Title | Towards a Critical History of Christian Zohar Criticism in the Seventeenth Century |
| Speakers | Marcello Cattaneo (Van Leer Jerusalem Institute), Itamar Ben Ami (Utrecht University) |
| Location | Alex Brenninkmeijerzaal (1.27) Johanna Hudiggebouw |
| Time | 15:30-17:00 |
| Abstract | The seventeenth century is often taken as a turning point in the study of religious texts by Western European Christian scholars: as a period that witnessed a shift from “sacred philology” guided by faith to “critical scholarship” built on the principles of reason. In parallel, the period saw a significant increase in the Christian knowledge of Hebrew and Jewish literature, as well as a push to exclude esotericism from academic theology in favour of a “rational” faith. My paper will engage with these narratives by focussing on the case of Christian scholars studying the Zohar, a key text in the Jewish esoteric tradition known as the Kabbalah. I will argue that by exploring the intersection of Zoharic study with Christian biblical scholarship, we can discover something unexpected, not just about the nature of philology as a critical enterprise, but also about how Christian orthodoxies constructed the image of Judaism. Itamar Ben Ami will comment upon Marcello's contribution. |
| Title | Scalar fields & spacetime-matter dichotomy |
| Authors | Antonio Ferreiro, Alex Fleuren & Niels Martens [Utrecht University] |
| Location | Buys Ballotgebouw - Room BBG 3.45 |
| Draft | Will be sent out in due course via the mailing list. |
| Time | 16:00-17:00 |
| Abstract | In this paper we analyse scalar-tensor theories–—specific instances of which include mainstream inflation and dark energy models—–in light of the spacetime–matter dichotomy. We argue that it is difficult to categorise the scalar fields as either a pure aspect of the spacetime structure or a pure form of matter, by focusing (among other arguments) on the Jordan vs Einstein frames of these theories. We present and evaluate various interpretational options available, concluding that the spacetime–matter dichotomy becomes untenable in this context. At the same time, the ontological and conceptual category of spacetime decouples from that of gravity, with the latter remaining viable in the context of scalar-tensor theories. |
| Title | On Reissner's Hypothesis: Historical proposals for a Machian unification of gravity and inertia |
| Speaker | Jonathan Fay [University of Bristol] |
| Location | Buys Ballotgebouw - Room BBG 3.45 |
| Time | 15:30-17:00 |
| Dinner | If you would like to join the speaker for dinner downtown, please let us know the day beforehand via cosmo-master.assistant@uu.nl. |
| Abstract | The combination of Mach’s hypothesis concerning the material origin of inertia in mass-interactions and Einstein’s equivalence hypothesis on the unity of inertia and gravity raises the intriguing possibility that gravity may be explained entirely as the dynamical part of a relativized law of inertia. This idea—which was not fully realised in general relativity—was first clearly articulated by a colleague of Einstein, Hans Reissner, so I have named it “Reissner’s hypothesis”. In this talk, I will revisit this overlooked idea and motivate its reconsideration by clarifying the philosophical appeal of Mach’s principle and Mach’s hypothesis. Drawing primarily on Dennis Sciama’s doctoral work, I will show how Reissner’s insight can be captured in an elegant equation linking the strength of gravitational coupling to the cosmic mass distribution. In the final part of my talk I discuss how similar expressions were considered by leading physicists such as Robert Dicke, John Wheeler and Pascal Jordan throughout the 20th Century for a variety of reasons not always related to Mach’s principle, I then explore some of the possible cosmological implications of these ideas. |
| Title | Between Theory and Experiment: Model Use in Dark Matter Detection |
| Author | Rami Jreige |
| Location | Buys Ballotgebouw - Room BBG 3.45 |
| Time | 16:00-17:00 |
| Abstract | There is a complex interplay between the models in dark matter detection experiments that have led to a difficulty in interpreting the results of the experiments and ascertain whether we have detected the particle or not. The aim of this paper is to categorise and explore the different models used in said experiments, by emphasizing the distinctions and dependencies among different types of models used in this field. With a background theory, models are categorised into four distinct types: background theory, theoretical, phenomenological, experimental and data. This taxonomy highlights how each model serves a unique purpose and operates under varying degrees of independence from their respective frameworks. A key focus is on the experimental model, which is shown to rely on constraints from both data and phenomenological ones. The article argues that while theoretical models provide a backdrop for understanding the nature of dark matter, the experimental models must stand independently, particularly in their methodological approaches. This is done via a discussion of the inherent challenges in dark matter detection, such as inconsistent results and difficulties in cross-comparison, stemming from the diverse modelling approaches. |
| Title | Rethinking Race in Microbiome Research: A Social Systems Approach |
| Speakers | Lucia Neco [Descartes Center] |
| Location | Westerdijk room, University Hall (Academiegebouw), Domplein 29 |
| Time | 15:30-17:00 |
| Abstract | Humans are social beings. However, we are not alone in the realm of social reality; we share this space with diverse entities, even more than just other animal organisms. In my work, I develop a new empirically-informed framework for studying social systems that broadens the concept of social reality. This framework is based on three building blocks of social systems: i.) interactions, ii.) relationships, and iii.) social units; and it redefines the manner in which various interactive systems are studied and perceived, encompassing diverse living entities at different levels of organization — from the intricate interplay between hosts and their microbiomes to the interactions among human beings and social groups. In this presentation, I will present this framework and how it can contribute to recent discussions about the adequacy of using race and/or ethnicity as scientific proxies in microbiome research. I propose that applying a social systems perspective to holobionts (hosts + microbiota), and their interactions challenges the use of race categories in microbiome studies. This perspective views human-microorganism associations as dynamic, evolving social networks which develop over time within complex and fluctuating contexts, rather than fixed traits, offering a more nuanced understanding of human diversity. Additionally, this approach can help us to rethink current models of planetary health and zoonotic diseases to properly acknowledge multispecies social relationships. This presentation is programmatic and outlines the work I will develop during my junior fellowship at the Descartes Centre over the next three months. The research is open to feedback and aims to foster collaborative engagement as it develops. |
| Title | The indirectnesses of dark matter detection |
| Author | Niels Martens [Utrecht University] |
| Location | Buys Ballotgebouw - Room BBG 3.45 |
| Draft | Will be sent out in due course via the mailing list. |
| Time | 16:00-17:00 |
| Abstract | Have we detected the cosmological dark matter? What does it mean to detect dark matter? In this paper we partially unpack this question by focusing on the various ways in which dark matter detections can be indirect. When a detection is labeled as indirect, one may be tempted to interpret that as the detection being epistemically inferior---in the sense of producing less reliable knowledge---compared to direct or less indirect detections of the same target entity (Elder, 2023). Similar attributions of epistemic inferiority do, after all, tend to be made, more generally, about mere observations (in astronomy) as compared to experiments (in terrestrial physics) (Hacking). In this chapter it is argued that 1) all potential detections of dark matter are more or less indirect (in the sense of indirectness that might have epistemic ramifications)---one should be very surprised that the term `direct dark matter detection' exist in the first place, given it being a dark or rather invisible form of dark matter; 2) no potential dark matter detection deserves to be called an experiment, in the sense that an experiment might be epistemically superior to a mere observation; 3) a direct comparison of the degree of indirectness of two potential detections of dark matter is typically neither possible (in any useful quantitative sense) nor particularly important; and 4) none of the above is particularly worrisome since these situations are commonplace in much of the natural sciences, or at least in astronomy. Instead, 5) different detection methods of dark matter are best construed as epistemically complementary---it is their combination that would achieve epistemic superiority over any single detection method. Rather than each detection method (potentially) providing us with the same knowledge of dark matter but with different degrees of trustworthiness, the various ways in which dark matter detections are indirect teach us different things about dark matter in each case. |
| Title | Can We Use Robustness Analysis to Evaluate the Hubble Tension? |
| Speaker | Marco Forgione [University of Milan] |
| Location | Buys Ballotgebouw - Room BBG 3.45 |
| Time | 15:30-17:00 |
| Dinner | If you would like to join the speaker for dinner downtown, please let us know the day beforehand via cosmo-master.assistant@uu.nl. |
| Abstract | The Hubble tension refers to the discrepancy between different measurements of the Hubble constant (H0), the expansion rate of the universe. These measurements involve local universe observations, such as the cosmic distance ladder method and early universe observations, primarily based on the Cosmic Microwave Background (CMB) and the standard model of cosmology. This paper applies robustness analysis to assess whether the discrepancy indicates unidentified systematic errors or the need for new physics beyond the standard cosmological model. However, I argue that robustness analysis faces challenges in cosmology due to the complexity and interdependencies of observational methods. Thus, I conclude that a more refined notion of robustness analysis and more data are needed before we can draw conclusions about the Hubble tension. |
| Title | Theory-mediated detection of novel phenomena in astrophysics: the case of the photon ring |
| Author | Jamee Elder [Tufts University] |
| Location | Buys Ballotgebouw - Room BBG 3.45 |
| Time | 16:00-17:00 |
| Abstract | This paper examines the opportunities and pitfalls of theory-mediated measurement in astrophysics. I locate the main danger not in the use of models of the target phenomena, but rather in the methodological context where these models are deployed. To illustrate this, I zoom in on a recent controversy among astronomers concerning attempts to detect the photon ring. I provide an account of what went wrong in this ``detection'' in conversation with other cases of (attempted) theory-mediated detection of novel phenomena in astrophysics---in particular, the retracted gravitational-wave detection claim by BICEP2 and the successful gravitational-wave detection claim by LIGO-Virgo. |
| Title | Descartes Centre Colloquium with Eric Jorink and Richard Calis |
| Speakers | Eric Jorink (Senior researcher Huygens Instituut, Teylers-chair ‘Enlightenment and Religion’ Leiden University) and Richard Calis (Assistant Professor in Intellectual History at Utrecht University) |
| Location | Bovenzaal, University Museum Utrecht (UMU), Lange Nieuwstraat 106, Utrecht |
| Time | 15:30-17:00 |
| Abstract | How can we write the history of science? In the past few decades, historians working in a variety of fields have challenged the obsolete—but enduring!—narrative of scientific progress that dominated much scholarship on the history of science in the twentieth century. Instead, scholars have focused on scholarly practices, approached science as historically and culturally contingent, identified the “stuff” of science, and looked beyond household names to ask new questions about how scientific knowledge is made, how it circulates, and which other types of knowledge are suppressed in the process. In this session, historians of science Eric Jorink and Richard Calis discuss their recent books to think further about how we can write the history of science today. They will introduce their work, respond to one another, and explore topics such as the recent shift from scientists’ ideas to their working practices, the potential of archival research for the history of science, and how processes of canonization change our understanding of ‘normal science at work’. |
There is no UPAC Colloquium this week.
| Title | Black Holes as Massive Spacetime |
| Authors | Sanne Vergouwen & Niels Martens [Utrecht University] |
| Location | Buys Ballotgebouw - Room BBG 3.45 |
| Draft | Will be sent out in due course via the mailing list. |
| Time | 16:00-17:00 |
| Abstract | What, if anything, makes the M in the Schwarzschild metric a physical mass? In this paper we present and evaluate various possible interpretations of M, all of which seem to capture some essential aspect of mass in the context of general relativity. We argue that the different interpretations give contradicting verdicts on whether supersubstantivalism is the appropriate ontology of static black holes described by the Schwarzschild solution to general relativity, suggesting that the spacetime-matter dichotomy is best given up. This conclusion is furthermore supported by a detailed conceptual analysis of two of the mass interpretations: the global ADM interpretation, and the special relativity trickle down interpretation. |
| Title | A Conceptual Analysis of Black Hole Entropy in String Theory |
| Speaker | Sebastian de Haro [University of Amsterdam] |
| Location | Buys Ballotgebouw - Room BBG 3.45 |
| Time | 15:30-17:00 |
| Dinner | Unfortunately there will be no dinner this month |
| Abstract | This talk aims to introduce the microscopic state counting of the extremal black hole, performed by Andrew Strominger and Cumrun Vafa, and to analyse the argument’s conceptual structure. In particular, I will identify the various inter-theoretic relations on which it depends. I will also discuss further conceptual questions that the calculation invites: Is the black hole in some sense the same physical system as the D-brane system? Is the black hole in some sense emergent from the D-brane system? |
| Comments | The talk by Alex Mathie has been postponed until next academic year. |
| Title | |
| Author | Dominic Ryder [LSE] |
| Location | Buys Ballotgebouw - Room BBG 3.45 |
| Time | 16:00-17:00 |
| Abstract | Stephen Hawking's derivation of Hawking radiation relied on one particular spacetime model, that of a star collapsing into a black hole which then remains in existence forever. He then argued that Hawking radiation implies this model should be thrown away in favour of a different model, that of an evaporating black hole. This aspect of Hawking's argument is an example of an idealization that is pervasive in the literature on black hole thermodynamics, but which has not yet been widely discussed by philosophers. The aim of this paper is to clarify the nature of Hawking's idealization, and to show a sense in which it leads to a paradox. After identifying this idealization paradox in classic derivations of Hawking radiation, I go on to show how various research programmes in black hole thermodynamics can be viewed as possible resolutions to the paradox. I give an initial analysis of the prospects for success of these various resolutions, and show how they shed light on both the philosophical foundations of both Hawking radiation on the nature of idealizations in physics. |
Hybrid workshop in Boston on the history, philosophy & culture of black hole observations: https://www.ngeht.org/4th-hpc-meeting
| Title | Evidence in cosmology: how galaxies became complicated |
| Authors | Anastasiia Lazutkina [University of Wuppertal] |
| Location | Buys Ballotgebouw - Room BBG 3.45 |
| Draft | Will be sent out in due course via the mailing list. |
| Time | 16:00-17:00 |
| Abstract |
| Title | Dark Matter: Explanatory Unification and Historical Continuity |
| Author | Simon Allzén [Stockholm University] |
| Location | Buys Ballotgebouw - Room BBG 3.45 |
| Time | 16:00-17:00 |
| Abstract | In recent years, the hope to confirm the existence of dark matter by experimentally detecting it has diminished significantly. After more than 30 years of experimental searches, many of the most promising candidates have since been ruled out, leaving the epistemic and scientific condition of dark matter in a state of suspension. In efforts to improve the epistemic justification for the dark-matter hypothesis, physicists have turned to philosophical arguments and historical narratives. In this paper, I explicate two such strategies -- explanatory unification and historical continuity -- applied in the context of dark matter. I argue that greater care and attention should be invested in the explanatory arguments to increase their strength, and that a survey of primary historical sources in astronomy renders the historical evidence for the continuity of dark matter substantially weaker. The quality and rigor of the philosophical and historical arguments which physicists are constructing could be substantially improved by increasing interdisciplinary practices. |
| Title | Stationary limit surfaces |
| Speaker | Christian Röken [University of Bonn] |
| Location | Buys Ballotgebouw - Room BBG 3.45 |
| Time | 15:30-17:00 |
| Dinner | If you would like to join the speaker for dinner downtown, please let us know the day beforehand via cosmo-master.assistant@uu.nl. |
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| Time | 15:30-17:00 |
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Location for UPAC Colloquium: Buys Ballot Building (unless indicated otherwise) - or online (Teams link will be sent via mailing list; see above for sign-up).
| Title | On the Origin of Time |
| Speaker | Thomas Hertog [KU Leuven] |
| Location | Buys Ballotgebouw - Room 0.69 |
| Time | 15:30-17:00 |
| Dinner | If you would like to join the speaker for dinner downtown, please let us know the day beforehand via cosmo-master.assistant@uu.nl. |
| Abstract | Perhaps the biggest question Stephen Hawking tried to answer in his extraordinary career was how the universe could have created conditions so perfectly hospitable to life. Pondering this mystery led him to study the big bang origin, but his early work ran into a crisis when the math predicted many big bangs producing many universes, most far too bizarre to harbor life. Holed up in theoretical physics departments across the globe, Hawking and I worked shoulder to shoulder for twenty years, to develop a fresh vision of the universe’s birth that could account for its mysterious biophilic design. At the heart of our cosmogony lies a novel quantum framework for early universe cosmology that predicts that time and indeed physics itself fade away back into the big bang, leading to a Darwinian-like perspective on cosmogenesis. In this colloquium I recount our quest to get a grips on the origin of time and the epistemic readjustment - long anticipated by philosophers like Hannah Arendt we have been led to. |
| Title | Integration in and of Susanne K. Langer’s Card-Index System: Theory and Practice |
| Speakers | Iris van der Tuin and Simon Dirks |
| Location | Theater (grote zaal), entrance Muntstraat 2a |
| Time | 15:30-17:00 |
| Abstract | Although logician, philosopher of art and interdisciplinarian Susanne K. Langer (1895-1985) published Harvard University Press’s most-sold monograph to date, she spent most of her career in temporary jobs in philosophy departments all over the USA and her work was never really canonized. Just as much of a conundrum is the fact that Langer’s card-index system, a system of 32.000 two-sided cards kept from 1916 until the 1980s, has never been researched. This talk presents Langer’s card-index system as an integrative device for Langer's own scholarship and for integration in current-day Langer scholarship and beyond. In order to understand the system as an integrative device, immanently, we present those cards that reflect on either integration/synthesis or on the system itself in the context of reflection on computerization that can also be found on cards. In order to work towards a scholarly future in which the card-index system and its contents—both individual cards and the lines of connection that run through the cards (Van der Tuin 2024)—can be used in research on Langer, adjacent topics, and philosophical and thematic debates per se, we end by presenting a digitized version of the card-index system, complemented with lessons learned for digital humanities projects. |
| Title | Quantum Gravity at Low Energies |
| Author | David Wallace [University of Pittsburgh] |
| Location | Buys Ballotgebouw - Room BBG 3.45 |
| Time | 16:00-17:00 |
| Abstract | I provide a conceptually-focused presentation of `low-energy quantum gravity' (LEQG), the effective quantum field theory obtained from general relativity and which provides a well-defined theory of quantum gravity at energies well below the Planck scale. I emphasize the extent to which some such theory is required by the abundant observational evidence in astrophysics and cosmology for situations which require a simultaneous treatment of quantum-mechanical and gravitational effects, contra the often-heard claim that all observed phenomena can be accounted for either by classical gravity or by non-gravitational quantum mechanics, and I give a detailed account of the way in which a treatment of the theory as fluctuations on a classical background emerges as an approximation to the underlying theory rather than being put in by hand. I discuss the search for a Planck-scale quantum-gravity theory from the perspective of LEQG and give an introduction to the Cosmological Constant problem as it arises within LEQG. |
| Title | Why Did the Dark Matter Hypothesis Supersede Modified Gravity in the 1980s? |
| Author | Antonis Antoniou [University of Bonn] |
| Location | Buys Ballotgebouw - Room BBG 3.45 |
| Draft | Will be sent out in due course via the mailing list. |
| Time | 16:00-17:00 |
| Abstract | In the 1960s and 1970s a series of observations and theoretical developments highlighted the presence of several anomalies which could, in principle, be explained by postulating one of the following two working hypotheses: (i) the existence of dark matter, or (ii) the modification of standard gravitational dynamics in low accelerations. In the years that followed, the dark matter hypothesis as an explanation for dark matter phenomenology attracted far more attention compared to the hypothesis of modified gravity, and the latter is largely regarded today as a non-viable alternative. The present article takes an integrated history and philosophy of science approach in order to identify the reasons why the scientific community mainly pursued the dark matter hypothesis in the years that followed, as opposed to modified gravity. A plausible answer is given in terms of three epistemic criteria for the pursuitworthiness of a hypothesis: (a) its problem-solving potential, (b) its compatibility with established theories and the feasibility of incorporation, and (c) its independent testability. A further comparison between the problem of dark matter and the problem of dark energy is also presented, explaining why in the latter case the situation is different, and modified gravity is still considered a viable possibility. |
| Title | The image of the university and pictures of (and in) the university |
| Speakers | Susanna Bloem, Laura Mol, Mette Bruinsma, Paul Ziche |
| Location | Muntstraat 2A, theater room/grote zaal (0.05) |
| Time | 15:30-17:00 |
| Abstract | In this colloquium, we want to address the image of the university, in the double sense of this phrase: images and pictures that are used for, or within, the university; and the way how we/the university wants to develop and propagate and image of itself. We will combine a number of brief presentations with discussion and group work – so please bring your own favourite pictures of the university to this meeting! In this way, we can combine aspects of the university’s material culture (we could also discuss your favourite hoodie or university mug!) with the more ideas-centered and impact-related question of the perception of the university (and, of course, this will also relate to the understanding of what ‘the university’ is, can, or should be). |
| Title | Spirit Without Dogma |
| Speaker | Karim Thébault [University of Bristol] |
| Location | Buys Ballotgebouw - BBG 3.45 |
| Time | 15:30-17:00 |
| Dinner | If you would like to join the speaker for dinner downtown, please let us know the day beforehand via cosmo-master.assistant@uu.nl. |
| Abstract | In the canonical approach one introduces a family of space-like surfaces and uses them to construct a Hamiltonian and canonical equal-time commutation relations. This approach is favoured by a number of authors became it seems to be applicable to strong gravitational fields and it is supposed to ensure unitarity. However the split into three spatial dimensions and one time dimension seems to be contrary to the whole spirit of relativity.’' (Hawking 1979 p. 747) The evolution of the system is via the infinitesimal canonical transformation generated by a function on phase space which vanishes on the constraint submanifold. Any infinitesimal canonical transformation generated by a function which vanishes on a constraint submanifold is normally regarded as a gauge transformation (Dirac 1958b, 1959, 1964). Thus, we may think of the evolution as the unfolding of a succession of gauge transformations. The 'multi-dimensional character of time' is just a reflection of the presence of a large group of smooth transformations on the space-time manifold, transformations which are, from the point of view of general relativity, pure gauge. (Ashtekar 1974, p. 1220) The time refoliation invariance of canonical general relativity is the basis upon which its advocates have rebutted the claim that the approach violates the 'spirit' of general relativity. In particular, by allowing spacetime to be decomposed into arbitrary sequences of space-like hypersurfaces, as encoded in the hyperspace deformation algebroid, the canonical formalism, which was first developed by Dirac in late 1950s, implements a substantive notion of background independence. It is often claimed, paradoxically, that this background independence in turn requires us to assume that time evolution is a gauge transformation. In this talk we critically examine this dogma in the context of the equivalence relation between transformations of evolution generating functions and spatial diffeomorphisms which is encoded in the deformation algebroid. |
There is no UPAC Colloquium on this fifth Tuesday of the month.
| Title | Does the present overdetermine the past? |
| Author | Craig W. Fox [Hebrew University of Jerusalem] |
| Location | Buys Ballotgebouw - BBG 3.45 |
| Time | 16:00-17:00 |
| Abstract | In an influential series of papers, Cleland (2001, 2002, 2011) argued that historical natural scientists employ a distinctive methodology—which exploits Lewis (1979)s asymmetry of over determination—that is capable of putting knowledge of the deep past on an epistemic par with experimental knowledge. Currie (2018) clarified the nature of the asymmetry claim and used it to argue for a more restricted form of optimism toward the historical sciences. This optimism is licensed by the evidential redundancy that the asymmetry of over determination guarantees. In this chapter I show that the argument for the asymmetry of over determination is circular and the thesis is false. Over determination toward the past is smuggled in from the start by ruling out of consideration so-called backtracking counterfactuals. By banning backtracking counterfactuals, consideration is restricted to possible worlds in which the over determination thesis holds. But in the actual world, the present is compatible with many different histories. |
This week's colloquium has been turned into a philosophy of black holes workshop (all afternoon).
| Title | Trust in Science |
| Speaker | Tessa van Charldorp (Utrecht University), Floris Cohen (Utrecht University) and Marie-Gabrielle Verbergt (Ghent University) |
| Location | Muntstraat 2A, theatre room/grote zaal (0.05) and online |
| Time | 15:30-17:00 |
| Abstract | It clearly is a key task for science (in the broad sense; it also is a task for the very institution ‘university‘, for instance) to develop and promote trust in science. In the present times, this task only gets ever more important. But how can we promote trust in what we do? In this colloquium, we’ll look at two concrete ways of doing that: conversation strategies for academics (presented by Tessa van Charldorp, associate professor in Language and Communication) – this can also be viewed under the more general label of having a ‘good conversation‘ in and about science; and the role of peer review for generating trust in science (presented by Marie-Gabrielle Verbergt, who is just starting her fellowship at the Descartes Centre, and Floris Cohen, emeritus professor for the History of Science and the former editor-in-chief of Isis). As always, there will be ample opportunity for discussion and exchange. |
| Title | What Reference Frames Teach Us About Symmetry Principles and Observability |
| Authors | Nicola Bamonti [Scuola Normale Superiore] & Henrique Gomes [Oxford University] |
| Location | Buys Ballotgebouw - BBG 3.45 |
| Draft | Will be sent out in due course via the mailing list. |
| Time | 16:00-17:00 |
| Abstract | This paper is an exploration of the nuanced realm of reference frames within the framework of General Relativity. Our analysis exposes a violation of Earman's SP1 principle in scenarios involving fields that are dynamically uncoupled, a common assumption for reference frames. Unlike other violations, we cannot foreclose it by eliminating background spacetime structure. Our analysis also leads us to challenge the conventional notion of partial observables as quantities that are associated with a measuring instrument and expressed within a coordinate system. Instead, we argue that a partial observable is inherently relational, even if gauge-variant, and needs dynamical coupling with other partial observables to form a bona-fide, gauge-invariant complete observables. This perspective allows us to distinguish between being relational and being gauge-invariant, two properties that are often conflated. |
| Title | Hawking & the history of black hole evaporation |
| Speaker | Jeroen van Dongen [University of Amsterdam] |
| Location | Buys Ballotgebouw - BBG 3.45 |
| Time | 15:30-17:00 |
| Dinner | If you would like to join the speaker for dinner downtown, please let us know the day beforehand via cosmo-master.assistant@uu.nl. |
| Abstract | Stephen Hawking's key result, the evaporation of black holes, celebrates its 50th anniversary this year. Hawking and the effect named after him, as key figure and result of twentieth century physics, have now become the subject of historical study. At the same time, the effect's notorious corollary, known as the information paradox, has become a focal point in philosophical debate on modern physics, and has remained a key element in studies of quantum gravity by today's physicists. In this talk, we present a source based reconstruction of how the result that black holes evaporate was attained, and reflect upon what it tells us about Hawking’s scholarship and its place in late twentieth century physics (based on joint work with Klaas Landsman). |
| Title | Re-Assessing the Experiment / Observation-Divide |
| Author | Florian J. Boge [TU Dortmund University] |
| Location | Buys Ballotgebouw - BBG 3.45 |
| Time | 16:00-17:00 |
| Abstract | The article reevaluates the distinction between experiment and observation. It is first argued that to get clear on what role observation plays in the generation of scientific knowledge, we need to distinguish “experiential observation” as a concept closely connected to experience from “observation” in a technical sense and from “field observation” as a concept that reasonably contrasts with “experiment.” It is then argued that observation construed as field observation can enjoy systematic epistemic advantages over experiment, contrary to appearances. |
| Title | |
| Speakers | David Baneke, Anna Lentink, Daniël de Vries, Liesbeth Bakker, Emma Mojet, Viktor Blåsjö, Paul Ziche |
| Location | University Hall (Academiegebouw), Domplein 29 |
| Time | 15:30-17:00 (followed by reception till 19:00) |
| Abstract | Now that the days get shorter and the weather colder, we could all use some good times with our fellow Cartesians. Therefore, in the spirit of Christmas, the Descartes Centre will dive into the heartwarming topic of what brings us together! Because science isn’t just about ideas and discoveries: it’s also about the people who make it happen. Get ready for a festive Christmas colloquium that will give you some deep insights into the stories of Community and Friendship in Science—collaboration, support, and camaraderie that shape scientific communities, both past and present. May the warmth of our friendships combined with short pitch-like academic presentations rekindle the fire in your souls. |
There is no UPAC Colloquium during the holidays.
There is no UPAC Colloquium during the holidays.
| Title | Consequences of an inflationary multiverse for laws of nature |
| Author | Maura Burke [Utrecht University] |
| Location | Buys Ballotgebouw - BBG 3.45 |
| Draft | Will be sent out in due course via the mailing list. |
| Time | 16:00-17:00 |
| Abstract | The existence of `the' multiverse has become a hotbed of discussion over the course of the previous 40 years in exotic theoretical physics, philosophy of science and popular media. The suggestion of an alien reality, where everything and anything is possible, where the laws of this universe do not apply is intuitively compelling and extends the imaginative capacity for agents who engage with the theories. There has been much debate about the extent to which any multiverse theory could really be considered scientific, insofar as the other universes are necessarily empirically opaque with respect to our observational horizons, although there are those who emphatically believe that multiverse science is simply normal science. In this paper, I am going to explore how the discussions surrounding multiverses demonstrate that our intuitions surrounding laws of nature are contradictory and paradoxical. I will provide some general background information on the Fine-Tuning argument and how it relates to the multiverse of inflationary cosmology. I will explore what we want our laws to be doing specifically in the fine-tuning and multiverse story, and more generally in our reasoning. (Forthcoming) I will introduce symmetries as a proposed solution for resolving some of conceptual tensions I identify, before moving on to sketch a novel response to the fine-tuning argument, the Variable Conceptualization of Constants. |
| Title | On the "direct detection" of Gravitational Waves |
| Author | Jamee Elder [Tuft University] |
| Location | Buys Ballotgebouw - BBG 3.45 |
| Time | 16:00-17:00 |
| Abstract | In this paper I provide an account of the sense in which the LIGO-Virgo Collaboration's 2015 observation, "GW150914" constituted the first "direct detection" of gravitational waves. Roughly, my account leverages the conceptual resources from recent work in the philosophy of measurement (especially Parker (2017)’s distinction between direct and derived measurements) to distinguish between these detections at the level of the modeling of the measurement processes. This distinction also has epistemic importance, because the choices scientists make about how to model measurement processes are related to the kinds of interventions they can perform to test the adequacy of their models. The direct/indirect distinction concerns the nature of the justification for confidence in the measurement outcome—in the direct case, this is based primarily on models of the measuring system, while in in the indirect case it also relies on models of a separate target system. Since astrophysical systems are not amenable to interventions, observations of the Hulse-Taylor system, and indeed the source of GW150914, cannot be “direct” in the same way that detections of gravitational waves are. |
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| Location | |
| Time | 15:30-17:00 |
| Abstract |
There is no UPAC Colloquium this week—Christian Röken's talk will now take place in June.
Schedule 2023-24
Location for UPAC Colloquium: Buys Ballot Building - Room 3.45; or online (Teams link will be sent via mailing list; see above for sign-up).
Location for Descartes Colloquium: Drift 21 - Sweelinckzaal (0.05).
| Title | On the Epistemic Status of Atmospheric Retrieval Models in Exoplanetary Science |
| Speaker | Vera Matarese [University of Perugia] |
| Location | Buys Ballotgebouw - Room 0.05 (NB. Different Room!) |
| Time | 15:30-17:00 |
| Abstract | Exoplanetary science provides a cutting-edge frontier not only for astrophysicists but also for philosophers of science. In this paper, I investigate the epistemic status of atmospheric retrieval models, which are indispensable techniques for gaining knowledge about the exoplanet atmospheric composition. In particular, I discuss the multifaceted epistemic import of these models by evaluating their structure, epistemic functions, and their potential vulnerability to the problem of incompatible models. |
| Dinner | If you would like to join the speaker for dinner downtown, please let us know the day beforehand via cosmo-master.assistant@uu.nl. |
Video | |
| Paper | |
| Authors | Alex Mathie [LMU München] |
| Location | Buys Ballotgebouw - Room 3.45 |
| Time | 16:00-17:00 |
| Abstract | It is generally accepted that science sometimes involves reasoning with analogies. Often, this simply means that analogies between disparate objects of study might be used as heuristics to guide theory development. Contemporary black hole physics, however, deploys analogical reasoning in a way that seems to overreach this traditional heuristic role. In this chapter, I describe two distinct pieces of analogical reasoning that are quite central to the contemporary study of black holes. The first underpins arguments for the existence of astrophysical Hawking radiation, and the second underpins arguments for black holes being ‘genuinely’ thermodynamical in nature. I argue that while these are distinct analogical arguments, they depend on one another in an interesting way: the success of the second analogical argument presupposes the success of the first. This induces a tension for those who wish to take black hole thermodynamics seriously, but who are sceptical of the evidence provided for astrophysical Hawking radiation by the results of analogue gravity. I consider three ways to resolve this tension, and show that each fails. |
| Title | Influential Patient Stories: Gynaecologists and their patients in the Utrecht Academic Hospital in the 1920s |
| Speaker | Jolien Gijbels |
| Location | Drift 21 - Sweelinckzaal (0.05) Hybrid (email dc-colloquium@uu.nl for link) |
| Time | 15:30-17:00 |
| Abstract | Historians have argued that the rise of modern hospital medicine since the end of the eighteenth century led to the disappearance of the patient’s narrative. Patients’ stories about illness and health were largely replaced by physical diagnoses when physicians started focusing on observable physical symptoms instead of patients' emotions and experiences. Yet, even in the context of medical specialization in 20th-century hospitals, patients' stories remained indispensable for doctors in making diagnoses. This paper examines the influence of the patient’s voice on doctors in the gynaecological department of the Academic Hospital in Utrecht in the 1920s. |
| Title | Another Critical Look at Inflationary Cosmology |
| Author | Alex Fleuren [Utrecht University] |
| Location | Buys Ballotgebouw - Room 3.45 |
| Draft | While there is a draft in the works, this talk is going to involve only a presentation of the work done so far, For those wishing to prepare the speaker suggests "A Critical Look at Inflationary Cosmology" by John Earman, Jesus Mosterin (https://www.jstor.org/stable/188736), sections 1-6 and the conclusion |
| Time | 16:00-17:00 |
| Abstract | In 1999, Earman and Mosterín published an influential critique on the research programme of inflationary cosmology. Their argument is that inflation does not make good on its claim of providing better explanations of cosmological observations than the standard Big Bang model. The first part of my talk will expand on this argument, specifically on the disconnect between inflation and particle physics, the generality of Wald’s cosmic no-hair theorem, and the possible reappearance of non-uniformities. I raise a second horizon problem that inflation may not be able to deal with. Earman and Mosterín do concede that inflation offers a successful explanation of the density perturbations seeding the formation of large-scale structures. In the second part of my talk, I will take a critical look at this alleged explanatory advantage. Hollands and Wald have suggested that inflation may not be necessary to explain the fluctuations of the CMB after all. |
| Title | Analogical Arguments and Emergent Gravity: The “Double-Gap” Problem |
| Speaker | Silvia de Bianchi [State University of Milan] |
| Location | Buys Ballotgebouw - Room 3.45 |
| Time | 15:30-17:00 |
| Abstract | Emergent Gravity (EG) is a framework in theoretical physics according to which “gravity is not a fundamental interaction” and “spacetime is a composite object approximately like a fluid” (Liberati 2017). Literature on recent attempts at providing robust models in emergent gravity are replete of moves labelled as “plausible” by scientists themselves. After reviewing important contributions in this framework, I show the sense in which plausibility is used in emergent gravity and discuss the limits encountered by this approach when it relies on analogical reasoning. In particular, I will discuss the use of acoustic black holes in EG and highlight the generation of what I call the “double-gap problem”, resulting in the difficulty of filling a gap between theory and experiment or models and simulations, as well as in an ontic jump from mathematics to physics. By no means this alter the significance that EG has within the landscape of theoretical physics, I rather try to provide a toolkit to avoid certain inconsistences and stimulate the debate about the epistemological questions raised by EG approaches. |
| Dinner | If you would like to join the speaker for dinner downtown, please let us know the day beforehand via cosmo-master.assistant@uu.nl. |
Video | |
| Paper | Why all these prejudices against a constant? (even shorter version here) |
| Authors | Eugenio Bianchi & Carlo Rovelli [University of Marseille] |
| Location | Buys Ballotgebouw - Room 3.45 |
| Time | 16:00-17:00 |
| Abstract | The expansion of the observed universe appears to be accelerating. A simple explanation of this phenomenon is provided by the non-vanishing of the cosmological constant in the Einstein equations. Arguments are commonly presented to the effect that this simple explanation is not viable or not sufficient, and therefore we are facing the "great mystery" of the "nature of a dark energy". We argue that these arguments are unconvincing, or ill-founded |
| Optional background reading | Dark Energy or Modified Gravity? by Smeenk & Weatherall |
| Title | Revamped Science Communication: A Tour of the Renewed University Museum Utrecht |
| Speaker | Suzanne van de Wateren, Reina de Raat, and Paul Lambers |
| Location | University Museum Utrecht (Lange Nieuwstraat 106, 3512 PN Utrecht) |
| Time | 14:30-18:00 |
| Abstract | We will take a tour of the “museum for curious people” guided by the people who have made it possible. We will explore the room Kijk, wij dieren (lit: ‘look at us animals’, where it is possible to observe objects of interest for natural history and Blaschka glass models). Paul Lambers, curator of the natural history and scientific instrument collections, will be the guide. Lastly, we will visit and explore the room Uitdokteren (lit: ‘figuring it out, physician style’, home of the medicine collection). Reina de Raat, curator of the medical and dental collections, will be the guide.
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| Title | Not the Measurement Problem’s Problem: Black Hole Information Loss with Schrödinger’s Cat |
| Author | Saakshi Dulani [Johns Hopkins University] |
| Location | Buys Ballotgebouw - Room 3.45 |
| Draft | Will be sent out in due course via the mailing list. |
| Time | 16:00-17:00 |
| Abstract | Recently, several philosophers and physicists have increasingly noticed the hegemony of unitarity in the black hole information loss discourse and are challenging its legitimacy in the face of the measurement problem. They proclaim that embracing non-unitarity solves two paradoxes for the price of one. Though I share their distaste over privileging specific interpretations of quantum theory, like Everettianism/Many Worlds, I’m not entirely on board with their charge against this case study. I argue that the manifestation of non-unitarity in Hawking’s original derivation is unrelated to what’s found in collapse theories or generalized stochastic approaches, thereby decoupling the two puzzles. |
| Title | The Non-Fundamentality of Spacetime |
| Speaker | Kian Salimkhani [University of Cologne] |
| Location | Buys Ballotgebouw - Room 3.45 |
| Time | 15:30-17:00 |
| Abstract | Spacetime fundamentalism is usually thought to face challenges from theories of quantum gravity. But the non-fundamentality of spacetime does not rely on speculative physics alone. Rather, one can give an interpretation of general relativity that supports some form of spacetime non-fundamentalism, or so I argue. I first clarify what it means to say that spacetime is or is not “fundamental”. I then sketch the argument and point out a few issues for inferences to (non-)fundamentality. |
| Dinner | If you would like to join the speaker for dinner downtown, please let us know the day beforehand via cosmo-master.assistant@uu.nl. |
| Video |
| Paper | |
| Authors | Jamee Elder [Tufts University] |
| Location | Buys Ballotgebouw - Room 3.45 |
| Time | 16:00-17:00 |
| Abstract | In this paper I discuss the first “multi-messenger” observations of a binary neutron star merger and kilonova. These observations, touted as “revolutionary,” included both gravitational-wave and electromagnetic observations of a single source. I draw on analogies between astrophysics and historical sciences (e.g., paleontology) to explain the significance of this for (gravitational-wave) astrophysics. In particular, I argue that having independent lines of evidence about a target system enables the use of argumentative strategies—the “Sherlock Holmes” method and consilience—that help overcome the key challenges astrophysics faces as an observational and historical science. |
| Title | Florentine Medical Alchemy in the Renaissance and a practical hands-on experience in the ArtLab |
| Speaker | Georgiana (Jo) Hedesan, Stefano Mulas, Thijs Hagendijk |
| Location | Bolognalaan 50 |
| Time | 15:30-17:00 |
| Abstract | Talk 1 (Jo Hedesan): Francesco I de Medici’s Alchemical Laboratory as Depicted by Jan Stradanus (1570) I will be discussing what this image and connected information might tell us about the Palazzo Vecchio laboratory and princely alchemy at the Medici court. The laboratory was set up by Cosimo I (1519-1574), the first Grand Duke of Tuscany. His son Francesco was also enthusiastic about laboratory practices: Stradanus’s painting portrays the prince working on the premises amongst other artisans. It seems that the primary purpose of the laboratory was focused toward making medicines. My talk will present the depiction of the laboratory, instruments and practices by linking them with what we know about 16th century medical alchemy. I will also discuss the complexity of ‘reconstructing’ the Palazzo Vecchio laboratory in light of Stradanus’s depiction, which draws on other contemporary representations and is meant to convey an underlying ideology. The laboratory of the Palazzo Vecchio seems to have been closed soon after Stradanus’s painting was finished. Francesco commissioned a new Medicean palace, and once the Casino di San Marco was finished in 1575, he relocated the majority of the alchemical works there, hence creating one of the first purpose-built scientific institutions in the world. |
| Title | Circularities in the search for empirical grounding for the cosmological principle |
| Author | Antonios Papaioannou [Utrecht University] |
| Location | Buys Ballotgebouw - Room 3.45 |
| Draft | - |
| Time | 16:00-17:00 |
| Abstract | The standard model of cosmology is based on the cosmological principle, a metaphysical assumption employed because of its simplifying potential for modelling purposes and purported success in matching observations. In this presentation, I critically examine the status and understanding of the principle as it is employed in cosmology, alongside its potential of being a testable hypothesis. I will primarily focus on some of the strategies employed by cosmologists to justify its use, to uncover if the reasoning is effective and if the evidence provided offers enough empirical support for the adoption of the principle, through the lens of the strongest current evidence in cosmology, the cosmic microwave background. I conclude with a discussion on general issues that emerge when attempting to empirically verify the principle that cannot be solved by gathering more precise data points, such as transitioning between scales, averaging in general relativity, and fitting parameters into a presupposed background. |
There is no colloquium on this fifth Tuesday of the month.
| Title | Speculative eliminative reasoning: on primordial black holes and their remnants (joint work with Mike Schneider) |
| Speaker | Juliusz Doboszewski [University of Bonn & Black Hole Initiative Harvard] |
| Location | Buys Ballotgebouw - Room 3.45 |
| Time | 15:30-17:00 |
| Abstract | Primordial black holes and their remnants can be used to construct various cold dark matter models. But PBHs remain unconfirmed, in that the outcomes of current observations are negative and continue the trend of successively ruling regions of viable parameters; and their remnants have highly speculative character. How to, then, assess their relevance to the ongoing cosmological research? We argue that despite these difficulties, the dark matter problem in late-stage cosmology can be seen as providing a rich empirical access point for investigations within early universe quantum gravity phenomenology. It is also an access point ready for philosophical investigations, including explicating notions of stability used in the context of remnant solutions; the extent to which the search for quantum gravity indeed lacks empirical input; the kind of eliminative reasoning used in searches for PHBs; and the issue of epistemic value of negative empirical results. |
| Dinner | If you would like to join the speaker for dinner downtown, please let us know the day beforehand via cosmo-master.assistant@uu.nl. |
Video | |
There is no colloquium on this Tuesday but you can join members of the UPAC group at the Bonn Black Hole Workshop.
| Title | Academia and Activism |
| Speaker | Mix of students and lecturers |
| Location | Drift 21 - Sweelinckzaal (0.05) Hybrid (email dc-colloquium@uu.nl for link) |
| Time | 13:00-17:00 |
| Abstract | (Preliminary) Program 14:00-14:30 Break/welcome with coffee and tea 14:30-16:00 Workshop with short presentations (among others: Erik van Sebille, Paul Boselie, Mattias Janson, Paul Ziche, ...) 16:00-16:15 Break 16:15-17:00 Lecture by Thomas Fossen (Leiden University) 17:00-17:30 General discussion 17:30-18:30 Drinks In order to be able to plan in detail, please register for this afternoon, indicating which part(s) of the program you want to participate in! Registration is possible by replying to this email or by sending an email to a.dendaas@uu.nl. You will receive a confirmation and some instructions on how to get to the theater.
A brief description of what we aim at with this day: „Academia and activism“. The urgency and the inter-/transdisciplinary appeal of this topic need not be argued for – the term “Academia” is adopted here to not only cover the different types of academic disciplines, from the humanities and the social sciences to the natural sciences and medicine, but to also include the academic institutions qua institutions. What we are interest in during this day – in accordance with the Descartes Centre’s mission – , are questions at the interplay between broader conceptual questions and concrete practices, and in how this relates to questions concerning the role of science and of scientific institutions. We want to organize this day together with institutions and colleagues throughout the university (and, this being a first and therefore also somewhat experimental event, we start on a moderate scale, with the intention to explore this format, and to take this as a first step towards larger events); this topic also comes forth from discussions within the UU’s “Open Science”-movement.
Here are some of the more specific questions that we may discuss – these are intended as suggestions and examples; we want to invite your ideas for topics that we can discuss during this event: - Is academia inherently activist, by virtue of its critical spirit? Or should academia, or should ‘science’ (in the broad sense of the term) be neutral and thus refrain from activism? (So we may also question the “and” in the title – should that rather be an “and/or”?) - Is science-based activism different from other forms of activism? - Is activism a challenge to ideals such as the free exchange of ideas within the scientific community? - Can an institution, qua institution, be activist, or is this an attitude or form of activity that needs to come from individuals? - Is activism a form of public engagement? Very concretely: should we include activist activities in the UU’s rewards-and-recognitions schemes? How does activism relate to the societal responsibility of the scientist? - How activist should the UU be in its communication strategies? How does science-based activism make us of specific media? - What is the role of symbols in activist activities – the gown, the lab-coat? What are the symbolically relevant venues for science-base activism? - Whom is an academic representing when they participate in activist activities, wearing the professorial gown or a lab-coat? Themselves? The university? ‘Academia’? ‘Science’? This question clearly has legal implications as well as conceptual ones. - What should be the role of activism in teaching at universities? Should we train students to become activists? - How do colleagues in academic administration, communication and other support roles come into contact with issues relating to activism? - A very generic question: All of these problems come together in a asking: What are the boundaries of ‚activism‘? What is the room to maneuver? And how do we keep an open dialogue on setting new boundaries? |
There is no colloquium on this Tuesday because of the 3rd History Philosophy & Culture of the ngEHT workshop, co-organised by UPAC.
| Title | The inferentialist guide to theory interpretation |
| Speaker | Tushar Menon [Australian Catholic University] |
| Location | Buys Ballotgebouw - Room 3.45 |
| Time | 15:30-17:00 |
| Abstract | The question of whether or not we should be scientific realists turns crucially on what it is to interpret a scientific theory. In this talk, I argue that the representationalist model, according to which we interpret theories by (i) deciding which objects in the world are represented (/referred to) by its central singular terms, and then (ii) making claims about these objects' properties and relations, is deeply flawed. In its place I propose a model based on a Sellars-Brandom-style inferentialism. On this view, theory interpretation is an exercise in understanding the contribution that scientific claims make to good inferences. This model allows for a much more compelling and nuanced view about how some scientific theories come to be about the world. To borrow terminology from Lehmkuhl (2020), this model underpins a careful, as opposed to a literal, interpretation of a physical theory. I demonstrate the power of this approach by discussing, as a case study, the interpretation of theories of dark matter. |
| Dinner | If you would like to join the speaker for dinner downtown, please let us know the day beforehand via cosmo-master.assistant@uu.nl. |
Video | |
| Paper | Promising Stabs in the Dark: Theory Virtues and Pursuit-Worthiness in the Dark Energy Problem |
| Authors | William J. Wolf [University of Oxford] and Patrick M. Duerr [University of Tübingen] |
| Location | Buys Ballotgebouw - Room 3.45 |
| Time | 16:00-17:00 |
| Abstract | The paper argues that we ought to conceive of the Dark Energy problem—the question of how to account for observational data, naturally interpreted as accelerated expansion of the universe—as a crisis of underdetermined pursuitworthiness. Not only are the various approaches to the Dark Energy problem evidentially underdetermined; at present, no compelling reasons single out any of them as more likely to be true than the other. More vexingly for working scientists, none of the approaches stands out as uncontroversially preferable over its rivals in terms of its rationally warranted promise, i.e. the reasons to further work on, explore and develop it. We demonstrate this claim by applying a Peircean economic model of pursuit-worthiness in terms of a cognitive cost/benefit estimate—with the instantiation of theory virtues as key indicators of cognitive gains—to the four main Dark Energy proposals (the cosmological constant approach, modified gravity, quintessence, and inhomogeneous cosmologies). Our analysis yields that these approaches do not admit of an unambiguous, or uncontroversial, ranking with respect to which ansatz deserves distinguished attention and research efforts. The overall methodological counsel that our analysis underwrites recommends a pragmatic double research strategy forward: to encourage and foster theory pluralism and the search for tests—with the goal of enhancing the testability of the ΛCDM model and “testing it to destruction”. |
| Title | Descartes Centre Summer Colloquium |
| Speaker | Members of the Descartes Centre |
| Location | Academiegebouw, Belle van Zuylenzaal, Domplein 29 |
| Time | 15:30-17:00 |
| Abstract |
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There is no colloquium on this Tuesday because of the 3rd HPP-NL Workshop in Leiden, co-organised by UPAC. Registration is possible here.
Location for UPAC Colloquium: Daltonlaan 500 - Room 4.27; or online (Teams link will be sent via mailing list; see above for sign-up).
Location for Descartes Colloquium: Drift 21 - Sweelinckzaal (0.05).
| Topic | On Kreisel's explication of the concept of finitism |
| Speaker | Lev Beklemishev (Steklov Mathematical Institute and Faculty of Mathematics of the Higher School of Economics in Moscow, currently Senior Fellow at the Descartes Centre) |
| Location | Drift 21 - Sweelinckzaal (0.05) (in-person only) |
| Time | 15:30-17:00 |
| Abstract | Finitistic methods appeared in the context of Hilbert's program in the foundations of mathematics. According to Hilbert, finitism contains those elementary methods of reasoning about finite objects (integers, words, ...) that are beyond any doubt and in some sense prior to any mathematical or axiomatic reasoning. Hilbert and Bernays gave examples of finitistically acceptable principles, but never clearly delineated the extent of these methods. Over the years, there were several proposals to make them mathematically precise, most notably by Kreisel and Tait. This is a work in progress talk in which I will discuss Georg Kreisel's approach of characterizing finitism in terms of formal systems defined by iteration of certain processes of reflection. His answer is equivalent to the association of finitistic theorems with the (forall)(exists) theorems of Peano arithmetic. However, Kreisel's approach is technically involved and is itself in need of clarification. I will overview the ideas in Kreisel's paper and outline various associated problems. Historically, the debate about the extent of finitism remained rather marginal; the issue can hardly ever be conclusively resolved. Nevertheless, the question is stubbornly alive, especially as a case study of the fundamental problem of how formal mathematical models of reasoning relate to contentual ones. |
This session was originally planned for 10 Oct, but switched with Simon Allzén's presentation as he lost his voice.
| Chapter | Laboratory Astrophysics: Lessons for Epistemology of Astrophysics |
| Author | Nora Mills Boyd [Siena College] |
| Book | Philosophy of Astrophysics - Stars, Simulations, and the Struggle to Determine What is Out There |
| Time | 16:00-17:00 |
| Location | Daltonlaan 500 - Room 4.27 |
| Abstract | Astrophysics is often cast as an observational science, devoid of traditional experiments, along with astronomy and cosmology. Yet, a thriving field of experimental research exists called laboratory astrophysics. How should we make sense of this apparent tension? I argue that approaching the epistemology of astrophysics by attending to the production of empirical data and the aims of the research better illuminates both the successes and challenges of empirical research in astrophysics than evaluating the epistemology of astrophysics according to the presence or absence of experiments. |
This presentation was originally planned for 3 Oct, but the speaker had lost his voice.
| Title | Scientificality and History as Epistemic Justification: A Case Study of Dark Matter |
| Speaker | Simon Allzén [Stockholm University] |
| Location | Daltonlaan 500 - Room 4.27 |
| Time | 15:30-17:00 |
| Dinner | If you would like to join the speaker for dinner downtown, please let us know the day beforehand via cosmo-master.assistant@uu.nl. |
| Abstract | Science in general, and particle physics in particular, has enjoyed immense success in revealing and explaining the parts and labour of our natural world by the methodological practice of prediction and experiment. This does not mean that theorists rest content with current confirmed models but are rather encouraged by the success to venture beyond the already confirmed. This has led theory development in physics to become increasingly decoupled from the methodological practice which historically served physics so well. While the hope and ambition for these theories is to couple to some testable part of our empirical horizon, many of them currently lack canonical forms of empirical confirmation, despite experimentalists' best efforts. The departure from canonical empiricism has led to a debate on the scientificality of such theories, where, somewhat surprisingly, historical narratives have been used to showcase the epistemic salience, robustness, or scientificality of the hypothesis under consideration. I assess the extent to which such historical narratives have been used to provide epistemic justification to the dark matter hypothesis, and provide an analysis of the success of, and motivations behind, such a strategy. |
Video | |
| Title | Losing track of the spacetime-matter distinction in astronomy and cosmology (COSMO-MASTER Project) |
| Speaker | Niels Martens [Utrecht University] |
| Location | Drift 21 - Sweelinckzaal (0.05) |
| Time | 15:30-17:00 |
| Abstract | The tradition of a strict conceptual dichotomy between space(time) and matter originates with Democritus' atomism—everything in our universe is ultimately reducible to either atoms (matter) or void (space)—and has reigned supreme ever since Newton. It is echoed by the famous container metaphor according to which space is conceived of as a container for matter, i.e. the contained (Sklar, 1974). Importantly, this conceptual dichotomy is the shared assumption needed by the substantivalist and relationalist about spacetime to formulate their further disagreement. Whereas this dichotomy may break down in the quantum gravity regime, I contend that reasons to worry about the breakdown of this dichotomy already appear in the context of established, experimentally well-confirmed theories, thereby following in the footsteps of Rynasiewicz (1996), Rovelli (1997) and others. This talk focuses on three case studies from cosmology and astronomy, namely dark matter, dark energy and black holes, illustrating in which sense these put pressure on a strict conceptual dichotomy between spacetime and gravity on the one hand and matter on the other, and elaborating upon the consequences of the breakdown of this distinction for philosophy and physics. |
| Title | Visualizing Epistemic and Aesthetic Choices in Black Hole Imaging |
| Author | Rodrigo Ochigame [Leiden University] |
| Location | Daltonlaan 500 - Room 4.27 |
| Time | 16:00-17:00 |
| Draft | No reading required; the author will talk us through the data/ interactive website. |
| Abstract | This work-in-progress session will present an interactive digital project (work in progress with Emilie Skulberg and Jeroen van Dongen) which examines the many epistemic and aesthetic choices involved in making an image of a black hole. Focusing on the iconic image of the Messier 87 black hole, published by the Event Horizon Telescope in April 2019, the project discusses how different choices at each stage could have affected the resulting image. In addition to raising philosophical questions and drawing comparisons to historical cases, the project shows alternative images of the black hole, applying other algorithms, parameters, and colors to the same data. |
There is no colloquium on this fifth Tuesday of the month.
| Title | Is the universe a black hole? |
| Speaker | Jonas Enander [University of Amsterdam] |
| Location | Daltonlaan 500 - Room 4.27 |
| Time | 15:30-17:00 |
| Abstract | The question whether the universe is a black hole has been raised by various researchers, motivated in part by the fact that the Schwarzschild radius associated with the matter content of the universe is roughly equal to the radius of the observable universe. In this talk, I will review the arguments for and against the claim that the universe is a black hole. I will also discuss the arguments for the claim that black holes can spawn baby universes. The talk is based on a chapter for an upcoming popular science book about black holes. |
| Dinner | If you would like to join the speaker for dinner downtown, please let us know the day beforehand via cosmo-master.assistant@uu.nl. |
Video | |
| Paper | |
| Authors | Milan M. Ćirković [University of Novi Sad ]& Slobodan Perović [University of Belgrade] |
| Location | Daltonlaan 500 - Room 4.27 |
| Time | 16:00-17:00 |
| Abstract | We historically trace various non-conventional explanations for the origin of the cosmic microwave background and discuss their merit, while analyzing the dynamics of their rejection, as well as the relevant physical and methodological reasons for it. It turns out that there have been many such unorthodox interpretations; not only those developed in the context of theories rejecting the relativistic (“Big Bang”) paradigm entirely (e.g., by Alfvén, Hoyle and Narlikar) but also those coming from the camp of original thinkers firmly entrenched in the relativistic milieu (e.g., by Rees, Ellis, Rowan-Robinson, Layzer and Hively). In fact, the orthodox interpretation has only incrementally won out against the alternatives over the course of the three decades of its multi-stage development. While on the whole, none of the alternatives to the hot Big Bang scenario is persuasive today, we discuss the epistemic ramifications of establishing orthodoxy and eliminating alternatives in science, an issue recently discussed by philosophers and historians of science for other areas of physics. Finally, we single out some plausible and possibly fruitful ideas offered by the alternatives. |
| Title | Digging up the past? The UU faculty of Geosciences in the colonial and postcolonial order |
| Speaker | Sophie Bijleveld [Utrecht University] |
| Location | Drift 21 - Sweelinckzaal (0.05) Hybrid (email dc-colloquium@uu.nl for link) |
| Time | 15:30-17:00 |
| Abstract | Under the working title “The UU faculty of Geosciences in the colonial and postcolonial order, ca. 1879- 1990” this PhD-project aims to investigate the Geosciences faculty’s entanglements with colonialism, as well as the processes and (dis)continuities after formal decolonization into the late 20th century. The presentation will briefly introduce some dimensions of these entanglements from the faculty’s history. However, movements within academia and beyond are increasingly calling for Dutch society not simply to acknowledge and engage with its colonial past but also for disciplines and institutions to decolonize. Yet in order to determine what such decolonizing should or could look like, or whether it is even possible to do so, these discussions also require us to grapple with questions about the concept and definition(s) of colonial science, as well as the “coloniality” in/of science. While not able to offer a ready answer to these big questions, I would like to end with an open exchange of ideas. The presentation is followed by a panel discussion with the participation of:
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| Title | A Universe Lost to the World? On Speculative Origins; Or, Why the Universe may be running away from Cosmologists. |
| Author | Adrien de Sutter |
| Location | Daltonlaan 500 - Room 4.27 |
| Draft | Will be sent out in due course via the mailing list. |
| Time | 16:00-17:00 |
| Abstract | Part of a larger project seeking to understand possible meaning behind the becoming scientific of our modern cosmology, this chapter attends to the brief history of the discipline over the twentieth century. After first addressing the increasingly speculative nature of the present account of the universe’s beginnings and its evolution, I inquire into the history of the science and into the possible origins for modern cosmology’s intemperate speculation. Contrary to the habitual claims of a universe, its beginnings, and its constituents revealing themselves to physicists as the result of increasingly precise empirical observations, I suggest that physical cosmology’s history is better understood as a steady unravelling, the disassembling of a total unity first achieved in the abstract with the first mathematical description of the universe in the early twentieth century. Rather than a picture of the universe slowly coming together, I contend that in physical cosmology we have a picture of a universe that is steadily falling apart while physicists struggle to hold on to the totality originally achieved. In this description, the momentum is not one of ever upward progress in physics, but one of decline. It is a universe that, I argue, always seems just about to run away from cosmologists who risk the inclusion of increasingly speculative and possibly chimeral beings in their efforts to keep the totalising unity of the universe together. |
| Title | Explanatory depth, predictive novelty, and pursuit-worthiness: comparing inflationary and bouncing cosmologies |
| Speaker | William Wolf [University of Oxford] |
| Location | Daltonlaan 500 - Room 4.27 |
| Time | 15:30-17:00 |
| Abstract | I develop and apply a multi-dimensional account of explanatory depth towards a comparative analysis of inflationary and bouncing paradigms in primordial cosmology. This establishes initial conditions fine-tuning, dynamical fine-tuning, and autonomy as a dimension of explanatory depth relevant to debates in contemporary cosmology regarding these theories of the early universe. I argue that these paradigms perform well along different dimensions of explanatory depth, resulting in an unclear verdict regarding which paradigm offers a better explanation for salient features of the early universe. I then argue that the most compelling reason underlying and justifying inflation’s dominant status over its competitors within cosmology is not these explanatory considerations, but rather has more to do several instances where it has displayed predictive novelty. |
| Dinner | If you would like to join the speaker for dinner downtown, please let us know the day beforehand via cosmo-master.assistant@uu.nl. |
| Topic | Christmas Colloquium - Science Communication Fails and Wins | ||||||||||||||||||
| Speaker | Members of the Descartes Centre | ||||||||||||||||||
| Location | Academiegebouw, Domplein 29 | ||||||||||||||||||
| Time | 15:30-17:00 | ||||||||||||||||||
| Abstract |
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Three-Week Holiday Break
| Paper | |
| Authors | Sean M. Carrol [John Hopkins University] |
| Location | Daltonlaan 500 - Room 4.27 |
| Time | 16:00-17:00 |
| Abstract | Cosmological models that invoke a multiverse - a collection of unobservable regions of space where conditions are very different from the region around us - are controversial, on the grounds that unobservable phenomena shouldn't play a crucial role in legitimate scientific theories. I argue that the way we evaluate multiverse models is precisely the same as the way we evaluate any other models, on the basis of abduction, Bayesian inference, and empirical success. There is no scientifically respectable way to do cosmology without taking into account different possibilities for what the universe might be like outside our horizon. Multiverse theories are utterly conventionally scientific, even if evaluating them can be difficult in practice. |
| Topic | Scientific Brushstrokes: Mural Paintings and the Art of Communication |
| Speaker | |
| Location | |
| Time | 15:30-17:00 |
| Abstract | This session will not only delve into the historical context and the decision-making involved in their creation but will also engage with their aesthetics and legacy. Why should train lovers learn about meteorologist and KNMI director Christophorus Buys Ballot? What will be the effect of Leonard Ornstein’s ‘drunkard walk’ mural on all visitors of nearby pubs and cafés? What is the most important contribution of Nobel Prize Winner Jacobus van ‘t Hoff? What were the arguments for adding biologist Johanna Westerdijk to this series of male scientists, and how does that affect our perception of these murals? Why did the mural of Caroline Bleeker move from ‘historical formulas’ to the invention of an instrument? Is there a kind of ‘period eye’ to the ‘Donders researches the eye’-mural? So many questions! |
| Title | The Holographic Dual of Black Hole Thermodynamics |
| Speaker | Manus Visser [University of Cambridge] |
| Location | Daltonlaan 500 - Room 4.27 |
| Time | 15:30-17:00 |
| Abstract | Black hole thermodynamics contains important clues for quantum gravity. Often black hole entropy is viewed as a low-energy constraint that every quantum theory of gravity has to satisfy. However, black hole thermodynamics itself poses conceptual puzzles, since it contains certain features that are seemingly different from those in standard textbook thermodynamics. For instance, black hole entropy scales with the horizon area, unlike the entropy of usual thermal systems that is proportional to the volume. Another puzzle is that the first law of black hole mechanics does not seem to contain a work term. These and other disanalogies between black hole thermodynamics and standard thermodynamics have led philosophers to argue that black holes are not really thermodynamic. In this talk I will explain how holography or gauge/gravity duality resolves these puzzles in an interesting way. In such a framework black holes in the ‘bulk’ geometry are dual to thermal states in the ‘boundary’ field theory. Crucially, these thermal states satisfy the usual laws of thermodynamics, for instance their entropy is extensive. I will develop a novel holographic ‘dictionary’ that relates the nonstandard laws of black hole thermodynamics to the standard laws of the dual field theory thermodynamics. |
| Dinner | If you would like to join the speaker for dinner downtown, please let us know the day beforehand via cosmo-master.assistant@uu.nl. |
Video | |
| Title | Data on the Conceptual Evolution of Dark Matter |
| Author | Simon Allzén [Stockholm University] |
| Location | Daltonlaan 500 - Room 4.27 |
| Draft | Will be sent out in due course via the mailing list. |
| Time | 16:00-17:00 |
| Abstract | The notion that dark matter is a (weakly interacting massive) particle is so ubiquitous in cosmology, astrophysics, theoretical physics and astronomy that one may be forgiven for thinking that this has always been the case. Using corpus data, I attempt to show the origin of this idea, and how the conceptual landscape of dark matter has evolved over the past 130 years. |
Prehistory
The UPAC colloquium continues and expands upon the 'Peebles Fan Club', a global, online, biweekly reading + work-in-progress group on the history, philosophy & sociology of the intersection of astronomy, particle physics and cosmology. This discussion group was founded in the wake of the online philosophy of dark matter workshop in March 2021, and started by reading most of Peebles' "Cosmology's Century".
# | 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 | |
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 | |
10 | 17 Nov 2021 | Cosmological Principle | |
11 | 1 Dec 2021 | Historical style in modern cosmology | |
12 | 15 Dec 2021 | Simulation in astronomy & cosmology | |
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 | |
16 | 9 March 2022 | Manchak on underdetermination in cosmology | Manchak 2009, 2011 |
17 | 23 March 2022 | The fate of TeVeS | |
| 18 | 6 April 2022 | Lambda & effective field theories | Koberinski and Smeenk 2022 |
| 19 | 20 April 2022 | Astrophysical modeling | Castellani and Schettino 2023 |
| 20 | 4 May 2022 | Steady-state theory | Kragh 2022 |
| 21 | 18 May 2022 | Lemaître and De Sitter at the BAAS Centenary | Baerdemaeker and Schneider 2022 |
