MCMP – Philosophy of Physics

Miklós Rédei (LSE) gives a talk at the MCMP Colloquium (13 May, 2015) titled "A Categorial Approach to Relativistic Locality". Abstract: In the talk relativistic locality of a probabilistic physical theory is interpreted as an interconnected web of properties which express compatibility of the theory with the underlying causal structure of spacetime. Four components of this web are distinguished: spatiotemporal locality, causal locality-Independence, causal locality-Dependence, and causal locality-Dynamic. These four conditions will be specified in terms of concepts from the categorical approach to quantum field theory and results are recalled indicating the extent to which an algebraic quantum field theory satisfying the Haag–Kastler axioms is causally local.

Miklós Rédei (LSE) gives a talk at the MCMP Colloquium (13 May, 2015) titled "A Categorial Approach to Relativistic Locality". Abstract: In the talk relativistic locality of a probabilistic physical theory is interpreted as an interconnected web of properties which express compatibility of the theory with the underlying causal structure of spacetime. Four components of this web are distinguished: spatiotemporal locality, causal locality-Independence, causal locality-Dependence, and causal locality-Dynamic. These four conditions will be specified in terms of concepts from the categorical approach to quantum field theory and results are recalled indicating the extent to which an algebraic quantum field theory satisfying the Haag–Kastler axioms is causally local.

Richard Dawid (MCMP) gives a talk at the MCMP Colloquium (29 April, 2015) titled "Bayesian Perspectives on the Higgs Search". Abstract: The history of the Higgs discovery is characterized by a specific constellation: trust in the existence of a Higgs particle was very strong already before the particle's discovery. This raises the issue of a Bayesian perspective on data analysis in high energy physics in an interesting way that differs from other contexts in the field where the deployment of Bayesian strategies was proposed.

Richard Dawid (MCMP) gives a talk at the MCMP Colloquium (29 April, 2015) titled "Bayesian Perspectives on the Higgs Search". Abstract: The history of the Higgs discovery is characterized by a specific constellation: trust in the existence of a Higgs particle was very strong already before the particle's discovery. This raises the issue of a Bayesian perspective on data analysis in high energy physics in an interesting way that differs from other contexts in the field where the deployment of Bayesian strategies was proposed.

Michael Stöltzner (South Carolina) gives a talk at the Irvine-Munich Workshop on the Foundations of Classical and Quantum Field Theories (14 December, 2014) titled "Best Possible Worlds and Random Walks: The Principle of Least Action as a Thought Experiment". Abstract: Over the centuries, no other principle of classical physics has to a larger extent nourished exalted hopes of a universal theory, has constantly been plagued by mathematical counterexamples, and has ignited metaphysical controversies than has the principle of least action (PLA). The aim of this paper is first to survey a series of modern approaches, among them the structural realist readings of Planck and Hilbert, a neo-Kantian relativized a priori principle, and more recent discussions about modality within the context of analytic metaphysics. But these considerations seem outrun by the broad applicability of the PLA beyond classical physics. In the case of Feynman’s path integral, the PLA does no longer amount to the distinction of the actual dynamics among the possible ones, but to the definition of a stochastic process to which all possibilities contribute with a certain probability. To reach a unified philosophical picture of all the various applications of the PLA and its kin, I suggest to consider them as a thought experiment about the applicability of mathematics to a physical problems.

Elena Castellani (Florence) gives a talk at the MCMP Colloquium (28 January, 2015) titled "Dualities". Abstract: Dualities are a key, intriguing ingredient in mathematics, logic and physics. This talk is concerned with physical dualities, in particular those dualities that have played "a central role in mapping out the structure of theoretical physics" in the past two decades (quoting Polchinski, 2015). Despite the importance of duality in field and string theory, philosophers are just starting to pay the due attention to the subject. This talk is meant as an introduction to discussing the significance of physical dualities, by pointing out the different relevant functions they play and the kinds of philosophical issues they connect or give rise to (in particular: theoretical equivalence and ontological indeterminacy).

Rüdiger Schack (Royal Holloway London) gives a talk at the Workshop on Quantum Computation, Quantum Information, and the Exact Sciences (30-31 January, 2015) titled "QBism and the Born rule". Abstract: By adopting a strictly personalist approach to probability, QBism takes the view that quantum states, and therefore also quantum information, reflect an agent’s personal degrees of belief about the consequences of his actions on the world. The quantum formalism enables the agent to make better decisions in the light of his previous experiences. This talk focuses on the central role played in quantum mechanics by the Born rule, which in QBism has a normative character similar to the rules of probability theory.

Chris Timpson (Brasenose College, Oxford) gives a talk at the Workshop on Quantum Computation, Quantum Information, and the Exact Sciences (30-31 January, 2015) titled "Quantum Information: Conceptual and Ontological Aspects". Abstract: In this talk I will explore some ways of thinking about what quantum information is. This topic has a certain intrinsic interest, but it is also important when trying to assess in a careful way what role the concept of information might have to play in fundamental physics. I shall argue for a view which is fairly ontologically deflationary about quantum information (this has significant impact on how we should understand the slogan ‘information is physical’ and for informational immaterialist views) and which sees quantum and classical (Shannon) information both as species of a single genus.

Gia Dvali (LMU-MPI & NYU) gives a talk at the MCMP Colloquium (14 January, 2015) titled "Corpuscular structure of geometry". Abstract: We review some recent ideas on quantum-corpuscular structure of gravitational metric backgrounds, such as black holes and cosmological spaces. We show how this picture sheds light on seemingly-mysterious properties, such as, black hole information processing and evaporation, as well as how it excludes eternal de Sitter space. This picture sheds a very different light on notion of "holography" and cosmological constant problem.

Rüdiger Schack (Royal Holloway London) gives a talk at the Workshop on Quantum Computation, Quantum Information, and the Exact Sciences (30-31 January, 2015) titled "QBism and the Born rule". Abstract: By adopting a strictly personalist approach to probability, QBism takes the view that quantum states, and therefore also quantum information, reflect an agent’s personal degrees of belief about the consequences of his actions on the world. The quantum formalism enables the agent to make better decisions in the light of his previous experiences. This talk focuses on the central role played in quantum mechanics by the Born rule, which in QBism has a normative character similar to the rules of probability theory.