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Profile: Charlotte Sophie Werndl (London School of Economics)
  1.  19
    Charlotte Werndl, Model-Selection Theory: The Need for a More Nuanced Picture of Use-Novelty and Double-Counting.
    This paper argues that common intuitions regarding a) the specialness of `use-novel' data for confirmation, and b) that this specialness implies the `no- double-counting rule', which says that data used in `constructing' a model cannot also play a role in confirming the model's predictions, are too crude. The intuitions in question are pertinent in all the sciences, but we appeal to a climate science case study to illustrate what is at stake. Our strategy is to analyse the intuitive claims in (...)
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  2.  16
    Charlotte Werndl (2016). On Defining Climate and Climate Change. British Journal for the Philosophy of Science 67 (2):337-364.
    The aim of the paper is to provide a clear and thorough conceptual analysis of the main candidates for a definition of climate and climate change. Five desiderata on a definition of climate are presented: it should be empirically applicable, it should correctly classify different climates, it should not depend on our knowledge, is should be applicable to the past, present and future and it should be mathematically well-defined. Then five definitions are discussed: climate as distribution over time for constant (...)
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  3.  99
    Charlotte Werndl (2009). What Are the New Implications of Chaos for Unpredictability? British Journal for the Philosophy of Science 60 (1):195-220.
    From the beginning of chaos research until today, the unpredictability of chaos has been a central theme. It is widely believed and claimed by philosophers, mathematicians and physicists alike that chaos has a new implication for unpredictability, meaning that chaotic systems are unpredictable in a way that other deterministic systems are not. Hence, one might expect that the question ‘What are the new implications of chaos for unpredictability?’ has already been answered in a satisfactory way. However, this is not the (...)
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  4.  56
    Charlotte Werndl (2009). Justifying Definitions in Mathematics—Going Beyond Lakatos. Philosophia Mathematica 17 (3):313-340.
    This paper addresses the actual practice of justifying definitions in mathematics. First, I introduce the main account of this issue, namely Lakatos's proof-generated definitions. Based on a case study of definitions of randomness in ergodic theory, I identify three other common ways of justifying definitions: natural-world justification, condition justification, and redundancy justification. Also, I clarify the interrelationships between the different kinds of justification. Finally, I point out how Lakatos's ideas are limited: they fail to show how various kinds of justification (...)
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  5.  11
    Charlotte Werndl, Determinism.
    This article focuses on three recent discussions on determinism in the philosophy of science. First, determinism and predictability will be discussed. Then, second, the paper turns to the topic of determinism, indeterminism, observational equivalence and randomness. Finally, third, there will be a discussion about deterministic probabilities. The paper will end with a conclusion.
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  6.  29
    Roman Frigg & Charlotte Werndl (2011). Explaining Thermodynamic-Like Behavior in Terms of Epsilon-Ergodicity. Philosophy of Science 78 (4):628-652.
    Gases reach equilibrium when left to themselves. Why do they behave in this way? The canonical answer to this question, originally proffered by Boltzmann, is that the systems have to be ergodic. This answer has been criticised on different grounds and is now widely regarded as flawed. In this paper we argue that some of the main arguments against Boltzmann's answer, in particular, arguments based on the KAM-theorem and the Markus-Meyer theorem, are beside the point. We then argue that something (...)
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  7. Charlotte Werndl & Roman Frigg (2015). Rethinking Boltzmannian Equilibrium. Philosophy of Science 82 (5):1224-1235.
    Boltzmannian statistical mechanics partitions the phase space of a sys- tem into macro-regions, and the largest of these is identified with equilibrium. What justifies this identification? Common answers focus on Boltzmann’s combinatorial argument, the Maxwell-Boltzmann distribution, and maxi- mum entropy considerations. We argue that they fail and present a new answer. We characterise equilibrium as the macrostate in which a system spends most of its time and prove a new theorem establishing that equilib- rium thus defined corresponds to the largest (...)
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  8.  8
    Charlotte Werndl & Roman Frigg, When Does a Boltzmannian Equilibrium Exist?
    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 state an existence theorem which provides general (...)
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  9.  26
    Charlotte Werndl, The Diversity of Model Tuning Practices in Climate Science.
    Many examples of calibration in climate science raise no alarms regarding model reliability. We examine one example and show that, in employing Classical Hypothesis-testing, it involves calibrating a base model against data that is also used to confirm the model. This is counter to the "intuitive position". We argue, however, that aspects of the intuitive position are upheld by some methods, in particular, the general Cross-validation method. How Cross-validation relates to other prominent Classical methods such as the Akaike Information Criterion (...)
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  10. Charlotte Werndl (2013). Justifying Typicality Measures of Boltzmannian Statistical Mechanics and Dynamical Systems. Studies in History and Philosophy of Science Part B 44 (4):470-479.
    A popular view in contemporary Boltzmannian statistical mechanics is to interpret the measures as typicality measures. In measure-theoretic dynamical systems theory measures can similarly be interpreted as typicality measures. However, a justification why these measures are a good choice of typicality measures is missing, and the paper attempts to fill this gap. The paper first argues that Pitowsky's justification of typicality measures does not fit the bill. Then a first proposal of how to justify typicality measures is presented. The main (...)
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  11.  17
    Roman Frigg & Charlotte Werndl (2012). Demystifying Typicality. Philosophy of Science 79 (5):917-929.
    A gas prepared in a non-equilibrium state will approach equilibrium and stay there. An influential contemporary approach to Statistical Mechanics explains this behaviour in terms of typicality. However, this explanation has been criticised as mysterious as long as no connection with the dynamics of the system is established. We take this criticism as our point of departure. Our central claim is that Hamiltonians of gases which are epsilon-ergodic are typical with respect to the Whitney topology. Because equilibrium states are typical, (...)
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  12.  18
    Charlotte Werndl (2011). On the Observational Equivalence of Continuous-Time Deterministic and Indeterministic Descriptions. European Journal for Philosophy of Science 1 (2):193-225.
    On the observational equivalence of continuous-time deterministic and indeterministic descriptions Content Type Journal Article Pages 193-225 DOI 10.1007/s13194-010-0011-5 Authors Charlotte Werndl, Department of Philosophy, Logic and Scientific Method, London School of Economics, Houghton Street, London, WC2A 2AE UK Journal European Journal for Philosophy of Science Online ISSN 1879-4920 Print ISSN 1879-4912 Journal Volume Volume 1 Journal Issue Volume 1, Number 2.
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  13.  42
    Charlotte Werndl (2009). Are Deterministic Descriptions and Indeterministic Descriptions Observationally Equivalent? Studies in History and Philosophy of Science Part B 40 (3):232-242.
    The central question of this paper is: are deterministic and indeterministic descriptions observationally equivalent in the sense that they give the same predictions? I tackle this question for measure-theoretic deterministic systems and stochastic processes, both of which are ubiquitous in science. I first show that for many measure-theoretic deterministic systems there is a stochastic process which is observationally equivalent to the deterministic system. Conversely, I show that for all stochastic processes there is a measure-theoretic deterministic system which is observationally equivalent (...)
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  14.  28
    Roman Frigg, Erica Thompson & Charlotte Werndl (2015). Philosophy of Climate Science Part I: Observing Climate Change. Philosophy Compass 10 (12):953-964.
    This is the first of three parts of an introduction to the philosophy of climate science. In this first part about observing climate change, the topics of definitions of climate and climate change, data sets and data models, detection of climate change, and attribution of climate change will be discussed.
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  15.  58
    Charlotte Werndl & Roman Frigg (2015). Reconceptualising Equilibrium in Boltzmannian Statistical Mechanics and Characterising its Existence. Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 49:19-31.
    In Boltzmannian statistical mechanics macro-states supervene on micro-states. This leads to a partitioning of the state space of a system into regions of macroscopically indistinguishable micro-states. The largest of these regions is singled out as the equilibrium region of the system. What justifies this association? We review currently available answers to this question and find them wanting both for conceptual and for technical reasons. We propose a new conception of equilibrium and prove a mathematical theorem which establishes in full generality (...)
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  16.  88
    Charlotte Werndl (2013). On Choosing Between Deterministic and Indeterministic Models: Underdetermination and Indirect Evidence. Synthese 190 (12):2243-2265.
    There are results which show that measure-theoretic deterministic models and stochastic models are observationally equivalent. Thus there is a choice between a deterministic and an indeterministic model and the question arises: Which model is preferable relative to evidence? If the evidence equally supports both models, there is underdetermination. This paper first distinguishes between different kinds of choice and clarifies the possible resulting types of underdetermination. Then a new answer is presented: the focus is on the choice between a Newtonian deterministic (...)
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  17.  24
    Roman Frigg, Erica Thompson & Charlotte Werndl (2015). Philosophy of Climate Science Part II: Modelling Climate Change. Philosophy Compass 10 (12):965-977.
    This is the second of three parts of an introduction to the philosophy of climate science. In this second part about modelling climate change, the topics of climate modelling, confirmation of climate models, the limits of climate projections, uncertainty and finally model ensembles will be discussed.
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  18.  22
    Charlotte Werndl, Determinism and Indeterminism.
    This article focuses on three themes concerning determinism and indeterminism. The first theme is observational equivalence between deterministic and indeterministic models. Here I discuss several results about observational equivalence and present an argument on how to choose between deterministic and indeterministic models involving indirect evidence. The second theme is whether Newtonian physics is indeterministic. I argue that the answer depends on what one takes Newtonian mechanics to be, and I highlight how contemporary debates on this issue differ from those in (...)
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  19.  16
    Katie Steele & Charlotte Werndl, Model-Selection Theory: The Need for a More Nuanced Picture of Use-Novelty and Double-Counting.
    This paper argues that common intuitions regarding a) the specialness of "use-novel" data for confirmation, and b) that this specialness implies the "no-double-counting rule", which says that data used in "constructing" a model cannot also play a role in confirming the model's predictions, are too crude. The intuitions in question are pertinent in all the sciences, but we appeal to a climate science case study to illustrate what is at stake. Our strategy is to analyse the intuitive claims in light (...)
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  20.  60
    Roman Frigg & Charlotte Werndl (2011). Entropy-A Guide for the Perplexed. In Claus Beisbart & Stephan Hartmann (eds.), Probabilities in Physics. Oxford University Press
    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 (...)
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  21.  19
    Charlotte Werndl (2012). Evidence for the Deterministic or the Indeterministic Description? A Critique of the Literature About Classical Dynamical Systems. Journal for General Philosophy of Science / Zeitschrift für Allgemeine Wissenschaftstheorie 43 (2):295-312.
    It can be shown that certain kinds of classical deterministic and indeterministic descriptions are observationally equivalent. Then the question arises: which description is preferable relative to evidence? This paper looks at the main argument in the literature for the deterministic description by Winnie (The cosmos of science—essays of exploration. Pittsburgh University Press, Pittsburgh, pp 299–324, 1998). It is shown that this argument yields the desired conclusion relative to in principle possible observations where there are no limits, in principle, on observational (...)
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  22.  16
    Katie Steele & Charlotte Werndl, Model Tuning in Engineering: Uncovering the Logic.
    In engineering, as in other scientific fields, researchers seek to confirm their models with real-world data. It is common practice to assess models in terms of the distance between the model outputs and the corresponding experimental observations. An important question that arises is whether the model should then be ‘tuned’, in the sense of estimating the values of free parameters to get a better fit with the data, and furthermore whether the tuned model can be confirmed with the same data (...)
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  23.  35
    Charlotte Werndl (2016). On Defining Climate and Climate Change. British Journal for the Philosophy of Science 67 (2):337-364.
    The aim of the article is to provide a clear and thorough conceptual analysis of the main candidates for a definition of climate and climate change. Five desiderata on a definition of climate are presented: it should be empirically applicable; it should correctly classify different climates; it should not depend on our knowledge; it should be applicable to the past, present, and future; and it should be mathematically well-defined. Then five definitions are discussed: climate as distribution over time for constant (...)
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  24.  4
    Roman Frigg & Charlotte Werndl, A New Approach to the Approach to Equilibrium.
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  25.  22
    A. J. J. Anglberger, B. Armstrong, W. F. Berger, N. Gratzl & Charlotte Werndl (2005). Book Review: Rezension: Rationalität in der Angewandten Ethik. [REVIEW] Kriterion: Journal of Philosophy 19:44-53.
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  26.  3
    Charlotte Werndl (2016). Philosophy of the Precautionary Principle, Daniel Steel. Cambridge University Press, 2015, Xv + 256 Pages. [REVIEW] Economics and Philosophy 32 (1):162-169.
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  27.  8
    Miklos Redei & Charlotte Werndl, On the History of the Isomorphism Problem of Dynamical Systems with Special Regard to von Neumann's Contribution.
    This paper reviews some major episodes in the history of the spatial isomorphism problem of dynamical systems theory. In particular, by analysing, both systematically and in historical context, a hitherto unpublished letter written in 1941 by John von Neumann to Stanislaw Ulam, this paper clarifies von Neumann's contribution to discovering the relationship between spatial isomorphism and spectral isomorphism. The main message of the paper is that von Neumann's argument described in his letter to Ulam is the very first proof that (...)
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  28.  20
    Charlotte Werndl & Katie Siobhan Steele (forthcoming). Climate Models, Confirmation and Calibration. British Journal for the Philosophy of Science.
    We argue that concerns about double-counting -- using the same evidence both to calibrate or tune climate models and also to confirm or verify that the models are adequate --deserve more careful scrutiny in climate modelling circles. It is widely held that double-counting is bad and that separate data must be used for calibration and confirmation. We show that this is far from obviously true, and that climate scientists may be confusing their targets. Our analysis turns on a Bayesian/relative-likelihood approach (...)
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  29.  5
    Charlotte Werndl, Probability, Indeterminism and Biological Processes.
    Probability and indeterminism have always been core philosophical themes. This paper aims to contribute to understanding probability and indeterminism in biology. To provide the background for the paper, it will first be argued that an omniscient being would not need the probabilities of evolutionary theory to make predictions about biological processes. However, despite this, one can still be a realist about evolutionary theory, and then the probabilities in evolutionary theory refer to real features of the world. This prompts the question (...)
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  30.  10
    Roman Frigg & Charlotte Werndl (2011). A Guide for the Perplexed. In Claus Beisbart & Stephan Hartmann (eds.), Probabilities in Physics. Oxford University Press 115.
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  31.  30
    Charlotte Werndl, Deterministic Versus Indeterministic Descriptions: Not That Different After All?
    The guiding question of this paper is: how similar are deterministic descriptions and indeterministic descriptions from a predictive viewpoint? The deterministic and indeterministic descriptions of concern in this paper are measure-theoretic deterministic systems and stochastic processes, respectively. I will explain intuitively some mathematical results which show that measure-theoretic deterministic systems and stochastic processes give more often the same predictions than one might perhaps have expected, and hence that from a predictive viewpoint these descriptions are quite similar.
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  32.  24
    Charlotte Werndl, Observational Equivalence of Deterministic and Indeterministic Descriptions and the Role of Different Observations.
    Recently some results have been presented which show that certain kinds of deterministic descriptions and indeterministic descriptions are observationally equivalent (Werndl 2009a, 2010). This paper focuses on some philosophical questions prompted by these results. More specifically, first, I will discuss the philosophical comments made by mathematicians about observational equivalence, in particular Ornstein and Weiss (1991). Their comments are vague, and I will argue that, according to a reasonable interpretation, they are misguided. Second, the results on observational equivalence raise the question (...)
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  33.  2
    Charlotte Werndl, The Formulation and Justification of Mathematical Definitions Illustrated By Deterministic Chaos.
    The general theme of this article is the actual practice of how definitions are justified and formulated in mathematics. The theoretical insights of this article are based on a case study of topological definitions of chaos. After introducing this case study, I identify the three kinds of justification which are important for topological definitions of chaos: natural-world-justification, condition-justification and redundancy-justification. To my knowledge, the latter two have not been identified before. I argue that these three kinds of justification are widespread (...)
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  34. Roman Frigg & Charlotte Werndl (forthcoming). Explaining the Approach to Equilibrium in Terms of Epsilon-Ergodicity. Philosophy of Science.
     
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  35. Charlotte Werndl (2009). Are Deterministic Descriptions and Indeterministic Descriptions Observationally Equivalent? Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 40 (3):232-242.
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  36. Charlotte Werndl, Do Microbes Question Standard Thinking in the Philosophy of Biology? Critical Notice of John Dupré "Processes of Life – Essays in the Philosophy of Biology".
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  37. Charlotte Werndl (2013). Justifying Typicality Measures of Boltzmannian Statistical Mechanics and Dynamical Systems. Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 44 (4):470-479.
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