The Metaphysics of Cosmology

We are pleased to announce the 'Metaphysics of Cosmology' workshop, to be held September 10–12, 2025, at the Institute of Philosophy, Università della Svizzera italiana (USI) in Lugano, Switzerland.

The workshop will explore metaphysical questions arising from contemporary physical theories of cosmology and spacetime, with particular focus on the nature of spacetime and the interrelationship between space, time, and spacetime.

Programme (abstracts below):

Wednesday, 10 Sept — Day 1

• 14:15–14:30 — Welcome & opening remarks
• 14:30–15:30 — James Read: Permanent underdetermination in dark energy and inflationary cosmology (replacing: Karim Thebault: Time and Knowledge in Quantum Cosmology) 
• 15:30–16:00 — Coffee break
• 16:00–17:00 — Henrique Gomes: What functionalism about time can do for shape dynamics

Thursday, 11 Sept — Day 2

• 09:30–10:30 — Damiano Costa: Separatism and Unitism about Spacetime
• 10:30—11:00 — Coffee break
• 11:00–12:00 — Lorenzo Lorenzetti & Enrico Cinti: Newton-Cartan Lessons for the Metaphysics of Time
• 12:00–13:30 — Lunch
• 13:30–14:30 — Oliver Pooley: How to recover spacetime structure from privileged coordinates
• 14:30–15:30 — Eleanor March: Minimal coupling, the strong equivalence principle, and the adaptation of matter to spacetime geometry
• 15:30–16:00 — Coffee break
• 16:00–17:00 — James Read: Regularity relationalism and general relativity

Friday, 12 Sept — Day 3

• 09:30–10:30 — Antonis Antoniou: Whence the desire to close the Universe? 
• 10:30—11:00 — Coffee break
• 11:00–12:00 — Federico Viglione: The Absoluteness of Absolute Cosmic Simultaneity
• 12:00–13:30 — Lunch
• 13:30–14:30 — Nicola Bamonti: In Search of Cosmic Time 
• 14:30–15:30 — Jim Weatherall: Cosmology, Spacetime Geometry, and the Metaphysics of Laws 
• 15:30–16:00 — Coffee break
• 16:00–17:00 — Silvia de Bianchi: Functionalism: Limits and Perspectives

Location:

• 10-11 September 2025: Room D1.13, USI East Campus, Via La Santa, 1, Lugano, Switzerland 
• 12 September 2025: Room 2.2, Department of Theology, USI West Campus, Via Buffi 13, Lugano, Switzerland

Website: https://www.usi.ch/en/feeds/32414

This workshop is generously supported by the Swiss National Science Foundation (SNSF) through a Scientific Exchange grant (grant number IZSEZ0_235599).

Organiser: Lorenzo Lorenzetti (USI)

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Abstracts

James Read

Title: Permanent underdetermination in dark energy and inflationary cosmology

Abstract: We identify troubling cases of so-called 'permanent underdetermination' in both dark energy and inflationary cosmology. We bring to bear (a) a taxonomy of possible responses to underdetermination, and (b) an understanding of both dark energy and inflationary cosmology from an effective field point of view. We argue that, under certain conditions, there are viable responses in both cases that alleviate some of the concerns about underdetermination in the dark energy and inflation sectors. However, outside of these specific scenarios, the epistemic threat of severe underdetermination will persist.

Henrique Gomes

Title: What functionalism about time can do for shape dynamics

Abstract: I will review two broadly geometrodynamical---and in part, Machian or relational---project, from the perspective of spacetime functionalism. I'll show how it is an example of functionalist reduction of the type advocated by D. Lewis (and now commonly referred to as 'the Canberra Plan'). The projects are: (1) the recovery of geometrodynamics by Hojman et al. (1976); (2) the deduction of the ADM Hamiltonian by myself and V. Shyam. I'll end with two positives and a negative note about what these results mean for Shape Dynamics. The positives are that (2) above gives a good rationale for the Hamiltonian that SD postulates, and that, indeed, we can find an independent route to SD that doesn't require the ADM Hamiltonian as a middleman. The negative aspect is that, even so, the Hamiltonian that SD postulates has a negative feature: even when uniquely determined, the SD Hamiltonian is non-local and lacks a natural, simple description in terms of shape degrees of freedom. 

Damiano Costa

Title: Separatism and Unitism about Spacetime

The theory of relativity is said to completely redefine our understanding of space, time, and their interrelation. Most notably, it is maintained that relativity presents a picture of space and time as unified into a single entity called spacetime, rather than as separate entities. But what exactly does it mean for space and time to stand as `separate' entities or as `unified' in spacetime? This essay provides the first systematic and comprehensive exploration of this understudied yet crucial ontological question. We articulate possible characterisations of the separation and unification of space and time in four distinct ways, through notions of (i) mereology, (ii) fundamentality, (iii) persistence, and (iv) existence. We analyse the relationships between these four accounts and argue that they are largely orthogonal. Hence we maintain that there is no single nor overarching notion of a ‘separatist’ or ‘unitist’ view of space and time. This discussion has significant implications for the interpretation of physical theories—clarifying the ontology of relativistic and Newtonian models of spacetime—and for broader metaphysical debates related to the existence and persistence of material objects.

Lorenzo Lorenzetti and Enrico Cinti (joint work with Marco Sanchioni)

Title: Newton-Cartan Lessons for the Metaphysics of Time

We challenge the consensus that A-theoretic views of time, along with traditional conceptions of spacetime as uniquely separable into space and time, are secure in pre-relativistic physics and threatened only by relativity. We show that Torsional Newton–Cartan theory---the most general version of Newton–Cartan theory, arguably providing the most natural setting for Newtonian spacetime---fails to sustain an absolute simultaneity relation. This is a largely understudied but central formulation of Newtonian gravity. To establish this, we introduce a standard that a spacetime theory must satisfy to admit absolute simultaneity and demonstrate that Newton–Cartan spacetimes with torsion do not meet it. This result undermines the consensus about a sharp contrast between the metaphysical consequences of Newtonian and relativistic physics and challenges potential strategies defending A-theories via Newton–Cartan–based quantum gravity frameworks, such as non-relativistic string theory and Hořava–Lifshitz gravity.

Oliver Pooley 

Title: How to recover spacetime structure from privileged coordinates

We show that the geometric structure of an arbitrary relativistic spacetime can be determined by the transformation groups associated with a collection of privileged coordinate systems.

Eleanor March

Title: Minimal coupling, the strong equivalence principle, and the adaptation of matter to spacetime geometry

Abstract: I discuss the relationships between minimal coupling, the strong equivalence principle, and 'adapted' dynamics in relativity theory. In particular, I show that minimally coupled, quasilinear, symmetric hyperbolic theories satisfy (i) the Geroch-Earman causality condition, (ii) the dominant energy condition, and (iii) the conservation condition. (This suffices for them to satisfy a version of the geodesic principle, and closes the gap between Geroch-Earman causality and the dominant energy condition.) I also discuss and clarify the meaning of the strong equivalence principle and its relationship to minimal coupling.

James Read (2nd talk)

Title: Regularity relationalism and general relativity

Abstract: According to 'regularity relationalism', which is a generalised Humean strategy developed by Huggett (2006), both spacetime structure and dynamical laws are to be understood as being subordinate to a more fundamental non-spatiotemporal Humean mosaic. Although the approach works (modulo some caveats and subtleties) in the case of theories with fixed spacetime structure (see Pooley (2013) and Stevens (2020)), it has yet to be applied to the case of general relativity, and there are prima facie serious roadblocks to doing so. In this talk, I will show how this can in fact be achieved, thereby offering a novel relationalist perspective on general relativity. (Joint work with Henrique Gomes, Tushar Menon, and Oliver Pooley.)

Antonis Antoniou

Title: Whence the desire to close the Universe?

Abstract: The spatial geometry of the universe is today widely believed to be flat based on combined data obtained during the 2000s. Prior to this, the geometry and the overall shape of the universe were essentially unknown. However, within the relevant literature one finds claims indicating a strong preference for a (nearly) closed universe, based on philosophical and other ''non-experimental'' reasons. The main aim of this article is to identify these reasons and assess the extent to which philosophical reasoning influenced the establishment of the dark matter hypothesis and the development of models for a closed universe. Building on groundwork laid by de Swart(2020), this study expands the discussion by (a) arguing that opinions on the geometry of the universe during the 1970s and 1980s were more divided than often assumed, (b) uncovering a lesser-known Machian argument for flat geometry proposed by Dennis Sciama, and (c) presenting a fine-tuning argument stemming from the `coincidence problem' articulated by Robert Dicke. The study provides a nuanced perspective on how philosophical considerations contributed to shaping early views on cosmology and dark matter and highlights the significant role philosophical reasoning can play in guiding scientific inquiry in physics.

Federico Viglione

Title: The Absoluteness of Absolute Cosmic Simultaneity

Cosmic simultaneity is the proposal that we can reconcile absolute simultaneity with relativity by means of the cosmic time function definable in certain highly symmetric cosmological models. Scholars have pointed out a heterogeneous array of obstacles in taking the route of cosmic simultaneity (Bourne 2004, pp. 114–116; 2006, p. 199, Wüthrich 2010; 2013, p. 17, Smeenk 2013, p. 15, Callender 2017, pp. 75–78, Callender and McCoy 2021, p. 4). In this paper, I follow this trend by highlighting a new serious problem which has been overlooked in the literature. My claim is that, once the relevant notion of absoluteness is clarified, an appealing approach to cosmic simultaneity turns out to be inconsistent. When this issue is considered alongside the already existing problems, the project of cosmic simultaneity reveals unsuccessful. My overall argument proceeds as follows. First, I clarify the relevant notion of absoluteness at stake in efforts to recover absolute simultaneity within relativistic physics. This will require a brief excursus on the reasons why absolute simultaneity may be desired in the first place. I argue for what I call the Causal Connection Condition (CCC): the fact that two distinct events are in a certain temporal relation (e.g. simultaneity) is absolute only if it obtains independently from the fact that any distinct causally disconnected event ex occurs. I proceed to introduce the notion of cosmic simultaneity, distinguishing between the epistemological and metaphysical approaches. According to the epistemological approach, the fact that two events are absolutely simultaneous is discoverable only if some physical properties are uniquely held by spacelike hypersurfaces in a certain foliation. However, this is not a necessary condition for the obtaining of absolute simultaneity itself. On the metaphysical approach, instead, for some events to be absolutely simultaneous, it is necessary that the spacetime points representing them belong to a privileged hypersurface. I suggest that some existing problems with cosmic simultaneity might be addressed by adopting the metaphysical approach. However, I show that, on the metaphysical approach, absolute simultaneity depends on causally disconnected events. Given the CCC, I conclude that metaphysical cosmic simultaneity is inconsistent.

Nicola Bamonti

Title: In Search of Cosmic Time

Abstract: This paper considers a new and deeply challenging face of the problem of time in the context of cosmology drawing on the work of Thiemann (2006). Thiemann argues for a radical response to the cosmic problem of time that requires us to modify the classical Friedmann equations. By contrast, we offer a conservative proposal for a solution to the problem. In our approach, we must reinterpret our criteria of observability in light of the clock hypothesis and the model-based account of measurement in order to preserve the Friedmann equations as the dynamical equations for the universe.

Jim Weatherall 

Title: Cosmology, Spacetime Geometry, and the Metaphysics of Laws

Abstract: I will discuss two problems for a Humean account of laws that arise from relativistic cosmology.  One problem concerns the interpretation of general relativity as a theory of spacetime geometry, and the other involves methodological principles employed by cosmologists.  I will conclude by discussing some properties that an account of laws needs to have in order to support the practice and interpretation of modern cosmology.

Silvia de Bianchi 

Title: Functionalism: Limits and Perspectives

Any philosophy of cosmology (including a metaphysics of cosmology) should address the question of whether functionalism is a fruitful approach to represent not only spacetime, but also other theoretical entities that enter in the construction of the model of the cosmos. In my talk, I shall highlight the strengths and limits of current functionalist approaches and discuss two case studies regarding spacetime singularities and causal set cosmology. In order to overcome the limits of spacetime functionalism and reductionist approaches, I present a new approach inspired by software engineering that I call "architectonic functionalism" and show how it recasts the case studies at hand in new terms.