Grace Field (University of Cambridge) Thursday at 9:30
Empirical Evidence or an Amusing Feat of Engineering? The problem with analogue simulation
Analogue simulation claims to use the behaviour of an experimentally accessible ‘source’ system to learn about the behaviour of an experimentally inaccessible ‘target’ system. But the status of that inferential link between the source and target systems has – not surprisingly – proved controversial. Dardashti et al. (2017; henceforth, ‘DTW’) and Dardashti et al. (2019; henceforth, ‘DHTW’) provide a philosophical defence of analogue simulation as “a novel form of scientific inference with the potential to be confirmatory” (DTW, 55). Crowther et al. (2019; henceforth, ‘CLW’) counter that analogue simulation, at least as presented by DTW and DHTW, suffers from vicious circularity. These three works therefore establish a debate that requires further adjudication, which will be the aim of this paper.
To begin, I present a summarized, synthesized, and clarified account of analogue simulation (section II). Based on that account, I go on to draw my own conclusions on the strengths and limitations of analogue experimentation. In section III.i, I explain why the most basic version of analogue simulation suffers from circularity. In section III.ii, I show that DTW does suffer from the circularity problem outlined in III.i: CLW’s criticism of DTW is convincing. However, I point out that the direct circularity in DTW is not present in DHTW; therefore, it is not fair of CLW to imply that their criticisms of DTW can apply equally well as criticisms of DHTW. DHTW make a suggestion that is not directly circular, and at first sight seems as if it might be able to rescue the confirmatory power of analogue simulation.
Ultimately, however, I will conclude in section III.iii that analogue simulation fails to provide confirmation for hypothesized features of the target system. It fails for a reason identified by CLW. But where CLW state that reason by referring back to their criticisms of DTW, I provide a separate argument (section IV). Namely, DHTW’s attempt to rescue analogue simulation requires us to be able to identify conditions that support the adequacy of both the source and target models as descriptions of their respective systems. Their attempt fails because the circumstances in which we need analogue simulation are precisely the circumstances in which we have no ability to identify those kinds of conditions.
James Wills (London School of Economics) Thursday at 10:30
Singular Behaviour and Theory Breakdown
The thesis defended in this paper is that General Relativity (GR) should not be rejected as broken down because of the Penrose-Hawking singularity theorems, as is often claimed. I identify two possible interpretations of the singularity theorems: one interpreting them as indicating theory breakdown and the other treating them as predictions. I point out that Hawking entertained both interpretations but did not endorse either one. In order to decide between them, we need to understand what `theory breakdown’ means. I show that this term is ambiguous and go on to suggest four precise senses. I conclude that GR does not break down in three of the senses but may be said to break down in the fourth. However, further technical research is required to determine whether GR really does break down in this fourth sense. If it is found to not break down, then one of the common justifications for pursuing theory change, the avoidance of singular behaviour, is not justified.
Thijs Hemme (Utrecht University) Thursday at 11:50
Reality as Four-Dimensional Being: Einstein on the Block Universe
In this paper I delve into Einstein’s thoughts on the notion of a block universe. Often authors refer to Einstein’s famous quote about the difference between the past, present and future being an illusion. However, Einstein has made much more substantial and illuminating statements on the ontology of time. Although Einstein’s scientific work regarding a four-dimensional spacetime has received much attention, his more philosophical ideas haven’t so much. Here I will thus lay out what Einstein’s beliefs were concerning the notion of a block universe, and how they evolved from 1905 until his death in 1955. We will see that all the sources indicate that Einstein had consistently believed in a block universe for at least the last forty years of his life. But despite this conviction, Einstein did worry about the seeming incompatibility of a block universe with our psychological experience of time. In his communication with other thinkers, we see early considerations of a possible reconciliation, foreshadowing pursuits that only in recent years have been undertaken in the philosophy of physics. Finally, this is also an invitation to authors to refer to Einstein’s more substantial statements on the topic when considering his block universe views, instead of his popular, but not so illuminating, quote.
Joanna Luc (Jagiellonian University) Thursday at 14:10
Symmetry and the Equivalence of Models
In this paper the thesis that symmetry-related models represent the same physical state (called SYM-ONE) is defended. It starts from reviewing potential counterexamples to this principle present in the literature (Belot 2013, Belot 2018, Fletcher 2018). All these counterexamples are realizations of the following scheme of argumentation: scientists distinguish between certain symmetry-related models, so they cannot be physically equivalent. Then, the paper proposes a framework to analyse these counterexamples that avoids abandoning SYM-ONE. The crucial ingredient of this framework is the distinction between theoretical and applied models. The latter include elements that are needed to relate theoretical models to the actual measurement, such as the choice of reference frame and the choice of units. The fact that symmetry-related models are often treated as representing physically distinct states in scientific practice can be explained by the fact that scientists use implicitly applied models, not their theoretical counterparts. Therefore, the arguments from scientific practice against SYM-ONE, as they stand, should not be regarded as valid.
Adrian K. Yee (University of Toronto) Thursday at 15:10
Econophysics: Making Sense of a Chimera
Econophysics is a relatively new discipline that is neither physics nor economics but a chimera, taking aspects of each. From physics, it borrows its methods; from economics, it aims to explain economic phenomena in particular. This paper provides a brief historical overview of how econophysical ideas have developed through thermodynamics, statistical mechanics, and scaling laws. Along the way, I discuss the role of idealizations, and what broader lessons philosophers of science might learn from econophysicists’ usage of them, concluding with a note of caution concerning considerations of explanatory transfer.
Miguel Ohnesorge (University of Cambridge) Friday at 9:30
How to be a Pluralistic Realist
I argue that epistemic pluralism conflicts with the success-argument for scientific realism and the classical correspondence theory of truth. I develop a solution to this compatibility problem based on a functionalist theory of scientific truth.
Present-day pluralists generally hold the view that there can or should be a plurality of (possibly incompatible) theories in the same field of science or regarding the same target phenomena. I will show how their claim entail the assumption that scientific activities can have multiple epistemic aims that are not reducible to some foundational aim such as truth or empirical adequacy.
Success arguments for scientific realism, however, conflict with epistemic pluralism, as they construe truth as the sole aim of scientific activities. To hold that truth, defined as correspondence to mind-independent facts, is the best explanation for scientific success, realist musts assume that scientific activities either aim at truth, or that their alternative epistemic aims are truth-indicators. The former denies a plurality of epistemic aims, the latter construes them as in principle reducible to truth.
I consider perspectival realism as an attempt to resolve this conflict, which is unsatisfactory as it collapses into correspondence-based realism when applied to cases of synchronic model or theory plurality.
Finally, I propose that the compatibility problems can be solved by adopting a non-classical theory of scientific truth, for which I draw on Hasok Chang’s notion of “operational coherence” and Michael Lynch’s pluralistic truth-semantics.
Laurie Letertre (Université Grenoble Alpes) Friday at 10:30
Causal Nonseparability and the Structure of Spacetime
Quantum entanglement is central to most philosophical puzzles related to quantum mechanics. Yet, it is not an exclusive property of quantum mechanics, as it is also found in theoretical generalizations thereof. Investigating the implications of entanglement in a broader context could shed a new light on the conceptual problems in quantum physics.
This work focuses on an operational theory called the process matrix formalism that generalizes quantum mechanics by relaxing the assumption of a well-defined causal structure. That broader theoretical context predicts the existence of noncausal quantum correlations, which violate the causal equivalent of Bell inequalities. A new notion of causal nonseparability is introduced, somehow suggesting the extension of entanglement to the geometry of spacetime.
The goal of this paper is to discuss the connection between the notions of quantum and causal nonseparability, and, in a realist framework, have a preliminary reflection regarding their potential implications for the world’s ontology. Three main questions will be developed:
1. A formal analogy with quantum nonseparability is at the basis of the articulation of the notion of causal nonseparability. What are the extent and the limits of this formal analogy, and does it have a deeper conceptual significance?
2. Can the link between causal nonseparability and noncausal correlations help to understand better the link between quantum nonseparability and nonlocality (and vice versa)?
3. What would be the possible implications of the above reflexions on the nature of space and time?
Athamos Stradis (King’s College London) Friday at 11:50
Exorcising Entropy from the Epistemic Arrow of Time
Why do we know more about the past than the future? The idea that this ‘epistemic arrow’ can be grounded in thermodynamic asymmetry is a popular view in philosophy and a received view in physics. This is usually attempted by adopting some ‘intermediary arrow’ as an explanatory halfway house. In this paper I examine two salient accounts in this vein, arguing that neither is adequate.
The first account, the ‘Computational Theory’, takes as its intermediary arrow the logical erasure of data within systems that remember their pasts. Whilst this arrow may well connect to the Second Law (as the theory claims), its alignment with the epistemic arrow is sim- ply taken for granted. The second account, the ‘Mentaculus Theory’, takes as its intermediary arrow the setting-up of records in their appropriate ready states. This suffers the reverse defect: whilst this universal feature of records might be grounded in the initial state of the universe (as the theory claims), we have no reason to suppose its entropic properties are relevant to this fact. In conclusion, intermediary arrows are hard-pushed to bridge a wide conceptual gap between an epistemic arrow on the one hand, and thermodynamic asymmetry on the other.