Western University Scholarship@Western Electronic Thesis and Dissertation Repository 5-25-2012 12:00 AM Explanation in Science James A. Overton The University of Western Ontario Supervisor Robert W. Batterman The University of Western Ontario Graduate Program in Philosophy A thesis submitted in partial fulfillment of the equirr ements for the degree in Doctor of Philosophy © James A. Overton 2012 Follow this and additional works at: https://ir.lib.uwo.ca/etd Part of the Philosophy of Science Commons Recommended Citation Overton, James A., "Explanation in Science" (2012). Electronic Thesis and Dissertation Repository. 594. https://ir.lib.uwo.ca/etd/594 This Dissertation/Thesis is brought to you for free and open access by Scholarship@Western. It has been accepted for inclusion in Electronic Thesis and Dissertation Repository by an authorized administrator of Scholarship@Western. For more information, please contact [email protected]. EXPLANATION IN SCIENCE Monograph by James Alexander Overton Graduate Program in Philosophy A thesis submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy The School of Graduate and Postdoctoral Studies The University of Western Ontario London, Ontario, Canada © James Alexander Overton, 2012 THE UNIVERSITY OF WESTERN ONTARIO School of Graduate and Postdoctoral Studies CERTIFICATE OF EXAMINATION Supervisor Examiners Robert W. Batterman Paul Humphreys Christopher Smeenk Gillian Barker Steven Kerfoot The thesis by James Alexander Overton entitled: Explanation in Science is accepted in partial fulfillment of the requirements for the degree of Doctor of Philosophy Date Chair of the Thesis Examination Board ii Abstract Scientific explanation is an important goal of scientific practise. Philosophers have proposed a striking diversity of seemingly incompatible accounts of explanation, from deductive-nomological to statistical relevance, unification, pragmatic, causal- mechanical, mechanistic, causal intervention, asymptotic, and model-based accounts. In this dissertation I apply two novel methods to reexamine our evidence about sci- entific explanation in practise and thereby address the fragmentation of philosophical accounts. I start by collecting a data set of 781 articles from one year of the journal Science. Using automated text mining techniques I measure the frequency and distribution of several groups of philosophically interesting words, such as \explain", \cause", \evidence", \theory", \law", \mechanism", and \model". I show that \explain" words are much more common in scientific writing than in other genres, occurring in roughly half of all articles, and that their use is very often qualified or negated. These results about the use of words complement traditional conceptual analysis. Next I use random samples from the data set to develop a large number of small case studies across a wide range of scientific disciplines. I use a sample of \explain" sentences to develop and defend a new general philosophical account of scientific explanation, and then test my account against a larger set of randomly sampled sentences and abstracts. Five coarse categories can classify the explanans and ex- plananda of my cases: data, entities, kinds, models, and theories. The pair of the categories of the explanans and explanandum indicates the \form" of an explana- tion. The explain-relation supports counterfactual reasoning about the dependence of qualities of the explanandum on qualities of the explanans. But for each form there is a different \core relation" between explanans and explanandum that sup- ports the explain-relation. Causation, modelling, and argument are the core relations for different forms of scientific explanation between different categories of explanans and explananda. This flexibility allows me to resolve some of the fragmentation in the philosophical literature. I provide empirical evidence to show that my general philosophical account successfully describes a wide range of scientific practise across a large number of scientific disciplines. Keywords: philosophy of science, scientific explanation, natural kinds, scientific models, scientific theories, text mining, case study method, philosophical methodol- ogy iii To Bob, for helping me find my own path. To Judy, for helping me follow it. To Lily and Andrew, whom we met along the way. iv Acknowledgements My doctoral research was made possible by a Canada Graduate Scholarships Doc- toral Fellowship from the Social Sciences and Humanities Research Council of Canada. I gratefully acknowledge funding from Prof. Robert Batterman, the Joseph L. Rotman Institute of Philosophy, the London Health Sciences Centre Department of Medical Imaging, and the Canadian Institutes for Health Research Team in Image-Guided Prostate Cancer Management. I would like to thank the University of Pittsburgh for hosting me for two semesters, in 2009 and 2011, with the support of a CGS Michael Smith Foreign Study Supplement from SSHRC. I would also like to thank the Tilburg Center for Logic and Philosophy of Science for a very pleasant and productive visiting fellowship in 2011. To the teachers, staff, colleagues, friends, and family who have supported me in so many ways, I continue to offer my most sincere thanks. v Contents Certificate of Examination ii Abstract iii Dedication iv Acknowledgementsv 1 Explanation1 1.1 Explanation in Science..........................1 1.2 Philosophy of Science...........................2 1.2.1 Background............................2 1.2.2 Philosophical Accounts of Scientific Explanation........5 1.2.3 Too Many Explanations.....................8 1.3 Evidence Base...............................9 1.4 Analysis.................................. 12 1.5 A General Philosophical Account of Scientific Explanation...... 14 1.6 Limitations................................ 18 1.7 Overview.................................. 19 2 Words 21 2.1 Text Mining................................ 21 2.2 Importance of Explanation........................ 23 2.3 Generality of Explanation........................ 31 2.4 Explanation as a Goal.......................... 36 2.5 Evidence for Philosophical Accounts.................. 38 2.6 Conclusions................................ 39 vi 3 Analysis 40 3.1 The Case Study Method......................... 41 3.2 Selecting Cases.............................. 41 3.3 Sample A { Cases of \Explain"..................... 42 3.3.1 Case A12............................. 43 3.3.2 Case A14............................. 43 3.3.3 Case A4.............................. 44 3.3.4 Case A10............................. 44 3.3.5 Phrases.............................. 45 3.3.6 Preliminary Glosses........................ 46 3.3.7 Normal Form........................... 47 3.3.8 Patterns of Explanation..................... 49 3.3.9 Categories and Forms....................... 51 3.3.10 The Structure of an Explanation................ 53 3.3.11 Revised Glosses.......................... 56 3.3.12 Preliminary Evidence for the Account.............. 58 3.4 A General Philosophical Account of Scientific Explanation...... 60 3.4.1 Connections to Other Accounts................. 61 3.5 Sample B { Beyond \Explain"...................... 62 3.5.1 Case B1.............................. 64 3.5.2 Evidence and Explanation.................... 65 3.5.3 The Importance of Explanation................. 66 3.6 Sample C { Aiming to Explain...................... 67 3.6.1 Case C4.............................. 67 3.6.2 Explanation as a Goal...................... 68 3.7 Evidence for This Account........................ 69 3.7.1 The Generality of Explanation.................. 69 3.7.2 Forms of Explanation....................... 71 3.7.3 Evidence for Other Accounts................... 73 3.8 Summary................................. 76 4 Data 78 4.1 Examples................................. 78 4.2 Discussion................................. 79 4.3 Data in Science .............................. 81 4.4 Forms of Explanation........................... 84 vii 4.4.1 Secondary: Data-Data...................... 84 5 Entities 86 5.1 Examples................................. 86 5.2 Discussion................................. 87 5.3 Entities in Science ............................ 92 5.4 Forms of Explanation........................... 93 5.4.1 Primary: Entity-Data...................... 94 5.4.2 Secondary: Entity-Entity..................... 95 6 Kinds 97 6.1 Examples................................. 97 6.2 Discussion................................. 98 6.3 Kinds in Science ............................. 102 6.4 Forms of Explanation........................... 103 6.4.1 Primary: Kind-Entity...................... 103 6.4.2 Secondary: Kind-Kind...................... 104 7 Models 106 7.1 Examples................................. 106 7.2 Discussion................................. 107 7.3 Models in Science ............................. 114 7.4 Forms of Explanation........................... 115 7.4.1 Primary: Model-Kind....................... 116 7.4.2 Secondary: Model-Model..................... 116 8 Theories 118 8.1 Examples................................. 118 8.2 Discussion................................. 120 8.3 Theories in Science ............................ 123 8.4 Forms of Explanation........................... 124 8.4.1 Primary: Theory-Model..................... 125 8.4.2 Secondary: Theory-Theory.................... 125 9 Conclusions 127 A Appendix A: Case Studies 130 A.1 Index of Cases by Form.......................... 131 viii A.2 Sample A................................. 132 A.3