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236When does a Boltzmannian equilibrium exist?In Daniel Bedingham, Owen Maroney & Christopher Timpson (eds.), Quantum Foundations of Statistical Mechanics, Oxford University Press. 2016.The received wisdom in statistical mechanics is that isolated systems, when left to themselves, approach equilibrium. But under what circumstances does an equilibrium state exist and an approach to equilibrium take place? In this paper we address these questions from the vantage point of the long-run fraction of time definition of Boltzmannian equilibrium that we developed in two recent papers. After a short summary of Boltzmannian statistical mechanics and our definition of equilibrium, we stat…Read more
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29Probability in Boltzmannian statistical mechanicsIn Gerhard Ernst & Andreas Hüttemann (eds.), Time, chance and reduction: philosophical aspects of statistical mechanics, Cambridge University Press. 2010.In two recent papers Barry Loewer (2001, 2004) has suggested to interpret probabilities in statistical mechanics as Humean chances in David Lewis’ (1994) sense. I first give a precise formulation of this proposal, then raise two fundamental objections, and finally conclude that these can be overcome only at the price of interpreting these probabilities epistemically.
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125Climate Science, The Philosophy ofInternet Encyclopedia of Philosophy. 2020.The Philosophy of Climate Science Climate change is one of the defining challenges of the 21st century. But what is climate change, how do we know about it, and how should we react to it? This article summarizes the main conceptual issues and questions in the foundations of climate science, as well as of the … Continue reading Climate Science, The Philosophy of →
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7Let us begin with a characteristic example. Consider a gas that is confined to the left half of a box. Now we remove the barrier separating the two halves of the box. As a result, the gas quickly disperses, and it continues to do so until it homogeneously fills the entire box. This is illustrated in Figure 1.
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28Of barrels and pipes: representation - as in art and scienceIn Otávio Bueno, Gerorge Darby, Steven French & Dean Rickles (eds.), Thinking about Science and Reflecting on Art: Bringing Aesthetics and the Philosophy of Science Together, . pp. 41-61. 2017.
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59We experience time in different ways, and we construct different kinds of representation of time. What kinds of representation are there and how do they work? In particular, how do we integrate temporal features of the world into our understanding of the mechanisms underlying representations in the media of perception, memory, art, and narrative? Le Poidevin’s well written and carefully argued book is an exploration of these questions. Although interesting in its own right, Le Poidevin pursues t…Read more
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142Making Confident Decisions with Model EnsemblesPhilosophy of Science 88 (3): 439-460. 2021.Many policy decisions take input from collections of scientific models. Such decisions face significant and often poorly understood uncertainty. We rework the so-called confidence approach to tackle decision-making under severe uncertainty with multiple models, and we illustrate the approach with a case study: insurance pricing using hurricane models. The confidence approach has important consequences for this case and offers a powerful framework for a wide class of problems. We end by discussin…Read more
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20Why do systems prepared in a non-equilibrium state approach, and eventually reach, equilibrium? An important contemporary version of the Boltzmannian approach to statistical mechanics answers this question by an appeal to the notion of typicality. The problem with this approach is that it comes in different versions, which are, however, not recognised as such, much less clearly distinguished, and we often find different arguments pursued side by side. The aim of this paper is to disentangle diff…Read more
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249Models occupy a central role in the scientific endeavour. Among the many purposes they serve, representation is of great importance. Many models are representations of something else; they stand for, depict, or imitate a selected part of the external world (often referred to as target system, parent system, original, or prototype). Well-known examples include the model of the solar system, the billiard ball model of a gas, the Bohr model of the atom, the Gaussian-chain model of a polymer, the MI…Read more
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12Scientific ModelsIn Sahotra Sarkar et al (ed.), The Philosophy of Science: An Encyclopedia, Vol. 2, Routledge. 2005.Models are of central importance in many scientific contexts. The roles the MIT bag model of the nucleon, the billiard ball model of a gas, the Bohr model of the atom, the Gaussian-chain model of a polymer, the Lorenz model of the atmosphere, the Lotka- Volterra model of predator-prey interaction, agent-based and evolutionary models of social interaction, or general equilibrium models of markets play in their respective domains are cases in point.
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62In its most common use, the term ‘model’ refers to a simplified and stylised version of the socalled target system, the part or aspect of the world that we are interested in. For instance, in order to determine the orbit of a planet moving around the sun we model the planet and the sun as perfect homogenous spheres that gravitationally interact with each other but nothing else in the universe, and then apply Newtonian mechanics to this system, which reveals that the planet moves on an elliptical…Read more
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59Fiction and scientific representationIn , . 2010.Understanding scientific modelling can be divided into two sub-projects: analysing what model-systems are, and understanding how they are used to represent something beyond themselves. The first is a prerequisite for the second: we can only start analysing how representation works once we understand the intrinsic character of the vehicle that does the representing. Coming to terms with this issue is the project of the first half of this chapter. My central contention is that models are akin to p…Read more
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39this study is to analyse the biomechanical influence of the been studied extensively, little is known how it is influclinical data on stability of the ankle joint. A two-dimenenced by the osseous joint configuration. Based on lateral..
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1Chaos is often explained in terms of random behaviour; and having positive Kolmogorov–Sinai entropy (KSE) is taken to be indicative of randomness. Although seemly plausible, the association of positive KSE with random behaviour needs justification since the definition of the KSE does not make reference to any notion that is connected to randomness. A common way of justifying this use of the KSE is to draw parallels between the KSE and ShannonÕs information theoretic entropy. However, as it stand…Read more
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52Ψ and out corresponding to the marble being inside or outside the box. These states are eigenvectors of the operator Bˆ , measuring whether the marble is inside or outside the box. The formalism of quantum mechanics..
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19Determinism and Chance from a Humean PerspectiveIn Thomas Uebel, Stephan Hartmann, Wenceslao Gonzalez, Marcel Weber, Dennis Dieks & Friedrich Stadler (eds.), The Present Situation in the Philosophy of Science, Springer. pp. 351--72. 2010.On the face of it ‘deterministic chance’ is an oxymoron: either an event is chancy or deterministic, but not both. Nevertheless, the world is rife with events that seem to be exactly that: chancy and deterministic at once. Simple gambling devices like coins and dice are cases in point. On the one hand they are governed by deterministic laws – the laws of classical mechanics – and hence given the initial condition of, say, a coin toss it is determined whether it will land heads or tails.2 On the …Read more
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30La mayoría de los modelos científicos no son objetos físicos y esto origina cuestiones importantes. ¿Qué clase de entidad son los modelos?, ¿qué es la verdad en un modelo? Y ¿cómo aprendemos sobre los modelos? En este escrito, argumento que los modelos tienen importantes aspectos en común con la ficción literaria y que, por tanto, las teorías de la ficción pueden aplicarse a estas cuestiones. En particular, argumento que la teoría de la simulación como la desarrolla Walton tiene los recursos par…Read more
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26A field guide to recent work on the foundations of statistical mechanicsIn Dean Rickles (ed.), The Ashgate Companion to Contemporary Philosophy of Physics, Ashgate. pp. 99-196. 2008.This is an extensive review of recent work on the foundations of statistical mechanics.
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185Entropy - A Guide for the PerplexedIn Claus Beisbart & Stephan Hartmann (eds.), Probabilities in Physics, Oxford University Press. pp. 115-142. 2011.Entropy is ubiquitous in physics, and it plays important roles in numerous other disciplines ranging from logic and statistics to biology and economics. However, a closer look reveals a complicated picture: entropy is defined differently in different contexts, and even within the same domain different notions of entropy are at work. Some of these are defined in terms of probabilities, others are not. The aim of this chapter is to arrive at an understanding of some of the most important notions o…Read more
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57A new approach to the approach to equilibriumIn Yemima Ben-Menahem & Meir Hemmo (eds.), Probability in Physics, Springer. pp. 99-114. 2012.Consider a gas confined to the left half of a container. Then remove the wall separating the two parts. The gas will start spreading and soon be evenly distributed over the entire available space. The gas has approached equilibrium. Why does the gas behave in this way? The canonical answer to this question, originally proffered by Boltzmann, is that the system has to be ergodic for the approach to equilibrium to take place. This answer has been criticised on different grounds and is now widely r…Read more
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3The time honoured philosophical issue of how to resolve the mind/body problem has taken a more scientific turn of late. Instead of discussing issues of the soul and emotion and person and their reduction to a physical form, we now ask ourselves how well-understood cognitive and social concepts fit into the growing and changing field of neuropsychology. One of the many projects that have come out of this new scientific endeavour is Zaidel’s (2005) inquiry into the neuropsychological bases of art.
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13Of barrels and pipes: representation - as in art and scienceIn Otávio Bueno, Steven French, George Darby & Dean Rickles (eds.), Thinking about Science, Reflecting on Art, Routledge. 2017.
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23Of barrels and pipes: representation - as in art and scienceIn Otávio Bueno, Steven French, George Darby & Dean Rickles (eds.), Thinking About Science, Reflecting on Art: Bringing Aesthetics and Philosophy of Science Together, Routledge. 2017.
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644Capturing the scientific imaginationIn Arnon Levy & Peter Godfrey-Smith (eds.), The Scientific Imagination, Oup Usa. 2019.
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15Scientific Representation Is Representation-AsIn Hsiang-Ke Chao & Julian Reiss (eds.), Philosophy of Science in Practice: Nancy Cartwright and the nature of scientific reasoning., Springer International Publishing. pp. 149-179. 2016.
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59Scientific representation is representation-asIn Hsiang-Ke Chao & Julian Reiss (eds.), Philosophy of Science in Practice: Nancy Cartwright and the nature of scientific reasoning., Springer International Publishing. pp. 149-179. 2016.
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The Continuing Influence of Imre Lakatos's Philosophy: a Celebration of the Centenary of his Birth (edited book)Springer. forthcoming.
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London School of EconomicsProfessor
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