JEFFERY L. JOHNSON Inferring and Explaining © 2019 Jefery L. Johnson Tis work is licensed under a Creative Commons Attribution 4.0 International License You are free to: Share— copy and redistribute the material in any medium or format Adapt— remix, transform, and build upon the material for any purpose, even commercially. Te licensor cannot revoke these freedoms as long as you follow the license terms. Under the following terms: Attribution—You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use. No additional restrictions—You may not apply legal terms or technological measures that legally restrict others from doing anything the license permits. Tis publication was made possible by the PDXOpen publishing initiative. Published by Portland State University Library Portland, OR 97207- 1151 Portland State University is a member of the Open Textbook Network Publishing Cooperative Contents Preface vii Dreaming and the External World 11 Practical Epistemology vii Te Evil Computer Scientist 12 Critical Tinking viii Can I Know Anything? 13 To My Student Readers viii Te Quest for Certainty 14 To My Fellow Philosophy Instructors ix Exercises 15 Two Further Debts ix Quiz Two 15 Notes ix Notes 15 1. valuInG truth 1 3. the concept of KnowleDGe 17 A Lofy Goal and a Practical Goal 1 Defnitions and Word Games 17 Te Skills and Values You Already Have 2 Te Myth of Defnition 18 Truth and the Contemporary Te Need for Conceptual Clarity 19 Academic Culture 3 Knowledge and Belief 20 Truth and the Popular Culture: Te Search for the Truth 21 Te Need to Respect Diferences 4 Epistemic Justifcation 21 Truth and the Popular Culture: What Does It Take to Be Justifed? 22 “Fake News” and “Alternative Facts” 5 An Unsolved Problem 23 A Plea for Critical Tinking 7 Exercises 24 Exercises 7 Quiz Tree 24 Quiz One 8 Notes 24 Notes 8 4. arGuments 25 2. sKeptIcIsm 9 Te Importance of Arguments 25 Descartes and the Arena of Reason 9 What Is an Argument? 26 Confdence- Undermining Possibilities 10 Logical Connection 28 iii Inference to the Best Explanation 28 A Pretty Picture of Science 51 iv A Couple of Arguments from A Better, But Untidy, Picture of Sherlock Holmes 29 Scientifc Disconfrmation 52 Schematizing the Argument 33 A Better, But Untidy, Picture of Start at the Bottom (Find the Conclusion) 34 Scientifc Confrmation 54 Contents Find the Relevant Evidence 34 Te Signifcance of New Data 54 Another Brokenhearted Teenager 35 Exercises 55 Exercises 35 Quiz Six 55 Quiz Four 35 Notes 56 Notes 35 7. semmelweIs anD chIlDBeD fever 57 5. Inference to the Best Childbed Fever 57 explanatIon 37 Ignác Fülöp Semmelweis 58 Inference to the Best Explanation 37 Te Vienna General Hospital 59 Schematizing Connie’s Argument 38 What Was Ten Known 60 Rival Explanations (of Connie’s Data) 38 Diferences in the Divisions 60 Rank Ordering Explanations (for “Fortuitous” New Data 62 Connie’s Argument) 39 An Experiment and a Treatment 62 Assessment of (Connie’s) Evidence 40 Semmelweis’s Evidence 63 What about Ties? 41 Te Tragedy of Semmelweis 64 Te Origins of Natural Language 41 Exercises 65 Te Argument Schematized 42 Quiz Seven 65 Rival Explanations (of Pinker Notes 65 and Bloom’s Data) 42 Ideal Agnostics 44 8. DarwIn anD common Descent 67 Rank Ordering the Explanations Making Sense of What Is Already Known 67 (for Pinker and Bloom’s Argument) 44 Te Two Teories 68 Disagreements 45 Rival Explanations to Common Descent 69 Don’t Forget about the Final Assessment Te Expanded Age of the Earth 70 of the Evidence! 46 Te Fossil Record 70 A Magical Encore? 46 Te Scala Naturae, or the Natural System 71 Exercises 46 Patterns of Geographical Distribution 71 Quiz Five 47 Morphological Facts 72 Notes 47 Embryological Facts 73 Darwin’s Evidence for Descent 6. new Data anD experImentatIon 49 with Modifcation 74 Te Crazy Philosopher’s Evidence 49 Natural Selection 75 Why Don’t You Just Test It? 50 One Long Argument 76 Exercises 77 Explaining the Correlations 108 Quiz Eight 77 CO2 and Global Temperatures 109 v Notes 77 Causation and Explanation 111 Contents A Sad Story 112 9. testImony 79 Exercises 115 A Letter of Recommendation 79 Quiz Twelve 115 Testimony regarding Miracles 82 Notes 115 Exercises 84 Quiz Nine 84 13. capItal punIshment Notes 84 anD the constItutIon 117 Arguments from Pure Principle: 10. textual InterpretatIon 87 For and against the Death Penalty 117 Sounds, Shapes, Gestures, and Constitutional Texts 118 Dashes and Dots 87 Precedent 119 Inference to the Best Explanation and Inference to the Best Constitutional Textual Interpretation 88 Interpretation 119 Authorial Intention 89 Some Key Constitutional Text 120 A Notorious Interpretation of Hamlet 89 Some Key Constitutional Precedent 122 A Contemporary Psychological Statistics and the Death Penalty 125 Interpretation of Hamlet 91 A Causal Explanation of the Correlation 127 Exercises and Quiz Ten 93 Some Other Contingent Realities 128 Notes 93 Exercises 129 Quiz Tirteen 129 11. statIstIcs 95 Notes 129 What Numbers Can Tell Us 95 Samples and Populations 96 14. evIDence, explanatIon, Couldn’t It Just Be a Fluke? 97 anD narratIve 131 Couldn’t the Sample Be Biased? 98 Legal Storytelling 131 Naomi Oreskes’s Study 100 O. J. Simpson 133 Rival Explanations of the Sample 101 Abe and His Daughter 134 Te Best Explanation? 103 Stories Tat Make Sense of Tings 135 Exercises 103 Mary Ann and Wanda 136 Quiz Eleven 104 Geneva and Brown v. Board of Education 137 Notes 104 Fabula and Sjuzet 139 Inference to the Best Narrative 140 12. correlatIons anD causes 107 Exercises 141 Correlations 107 Quiz Fourteen 141 Explaining the Numbers 108 Notes 141 15. explanatory vIrtue vi anD truth 143 Two Huge Problems 143 Literary Darwinism 146 Sally and Ann 147 Contents Disagreement 148 Truth 149 Exercises 151 Quiz Fifeen 151 Notes 151 PrefaCe How is philosophy learned? A better question is how can thinking skills be acquired? TeTh e thinkingthinking inin questionquestion involvesinvolves attendingattending toto basicbasic structuresstructures ofof thought. Tis can be done well or badly, intelligently or ineptly. But doing it well is not primarily a matter of acquiring a body of knowledge. It is more like playing a piano well. It is a “knowing how” as much as a “knowing that.” — sImon BlacKBurn1 Practical Epistemology answer) improves one’s general critical thinking Tis is a book about what I am calling practical skills. So I would claim that a good philosophy epistemology. It refects two of my most deeply course is good for a lot more than just general held prejudices as a teacher. I believe that education credits and will be of value no matter abstract questions in academic philosophy are what your major is or career aspirations are. intrinsically interesting not just to profession- Te book begins with three classic questions als but to smart, inquisitive students as well. I in the theory of knowledge—What is the value of also believe that carefully refecting on the great truth? Can we know anything? What is the nature questions in Western philosophy (What is knowl- of knowledge in the frst place? It then introduces edge? Is it possible? Does God exist? Do we have a little logic and a particular theory of evidence genuine free will?— to say nothing of the equally evaluation— inference to the best explanation. important moral, political, and legal questions Tis view of argument analysis is the corner- that philosophers have posed and attempted to stone of my entire discussion throughout the vii book. We then turn our attention to some issues If this book accomplishes nothing else, I hope viii in the history and philosophy of science—the it at least tempts readers to utilize the somewhat role of experiments, Semmelweis’s discovery of structured, almost ritualistic procedure I am call- the causes of childbed fever, and Darwin’s theory ing the inference-to-the-best-explanation recipe of common descent by natural selection. Te as a test of the quality of evidence presented in PrefaCe PrefaCe book concludes with discussions of capital an argument. I do believe that you will be pleas- punishment, evidence as narrative, and some antly surprised at how ofen it proves useful. thoughts about the nature of evidence and truth. To My Student Readers Critical Thinking I want this book to be fun, interesting, and use- This brings me to my second, and even ful to you. Depending on your academic and more deeply held, prejudice as a philosophy intellectual personality, it may prove impossible teacher. I am committed to the value of critical to accomplish all these goals. But even if I fail in thinking—or, as it is sometimes called, practical, conveying the intrinsic interest in philosophical or informal, logic—as a tool for undergraduate and intellectual questions, and even if you fnd and professional success. I pretend little modesty my style boring or pedantic, I do hope you will here. I have heard from too many students that discover the utility in the careful, systematic the techniques developed in chapters 4 through study and analysis of arguments. Inference to 12 have proven not just useful but essential in the best explanation is not the only approach their other undergraduate and graduate classes, to argument analysis (though I remain con- and indeed, in their professional lives. vinced it is the most valuable), but it is one that Where I do claim some modesty, however, invites wide application to the kinds of argu- is that I take little credit for discovering these ments we fnd in our daily and professional techniques.