UPAC Colloquium
The weekly, hybrid UPAC colloquium on the philosophy of astronomy, astro(particle)physics and cosmology takes place on Tuesdays and rotates between the following four 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 |
3 | Pre-existing Descartes colloquium on history & philosophy of science | 15:30-17:00 CE(S)T | In-person only |
4 | Work-in-progress session (WiP) | 16:00-17:00 CE(S)T | Hybrid |
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Schedule 2023-24
Location for reading group, speaker & work-in-progress sessions: 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. |
Title | Scientificality and History as Epistemic Justification: A Case Study of Dark Matter |
Speaker | Simon Allzén |
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. |
Chapter | Laboratory Astrophysics: Lessons for Epistemology of Astrophysics |
Author | Nora Mills Boyd |
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. |
Topic | |
Speaker | |
Location | Drift 21 - Sweelinckzaal (0.05) (in-person only) |
Time | 15:30-17:00 |
Abstract |
Title | Visualizing Epistemic and Aesthetic Choices in Black Hole Imaging |
Author | Rodrigo Ochigame |
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 |
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. |
Paper | |
Authors | Milan M. Ćirković & Slobodan Perović |
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 | Losing track of the spacetime-matter distinction in astronomy and cosmology (COSMO-MASTER Project) |
Speaker | Niels Martens |
Location | Drift 21 - Sweelinckzaal (0.05) (in-person only) |
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 | 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. |
Topic | |
Speaker | |
Location | Daltonlaan 500 - Room 4.27 |
Time | 15:30-17:00 |
Abstract | |
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 |
Speaker | |
Location | tbd - (in-person only) |
Time | 15:30-17:00 |
Abstract |
Topic | |
Speaker | |
Location | Daltonlaan 500 - Room 4.27 |
Time | 16:00-17:00 |
Abstract |
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 |