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Twelfth Edition
Critical Thinking
Brooke Noel Moore Richard Parker California State University, Chico
with help in Chapter 12 from Nina Rosenstand and Anita Silvers
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CRITICAL THINKING, TWELFTH EDITION
Published by McGraw-Hill Education, 2 Penn Plaza, New York, NY 10121. Copyright © 2017 by McGraw-Hill Education. All rights reserved. Printed in the United States of America. Previous editions © 2015, 2012, and 2009. No part of this publication may be reproduced or distributed in any form or by any means, or stored in a database or retrieval system, without the prior written consent of McGraw-Hill Education, including, but not limited to, in any network or other electronic storage or transmission, or broadcast for distance learning.
Some ancillaries, including electronic and print components, may not be available to customers outside the United States.
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Library of Congress Cataloging-in-Publication Data
Names: Moore, Brooke Noel, author. | Parker, Richard (Richard B.), author. Title: Critical thinking / Brooke Noel Moore, Richard Parker, California
State University, Chico; with help in chapter 12 from Nina Rosenstand and
Anita Silvers. Description: Twelfth Edition. | Dubuque, IA : McGraw-Hill Education, 2016. Identifiers: LCCN 2016021518 | ISBN 9781259690877 (alk. paper) | ISBN
1259690873 (alk. paper)
Subjects: LCSH: Critical thinking. Classification: LCC B105.T54 M66 2016 | DDC 160—dc23 LC record available at https://lccn.loc.gov/2016021518
The Internet addresses listed in the text were accurate at the time of publication. The inclusion of a website does not indicate an endorsement by the authors or McGraw-Hill Education, and McGraw-Hill Education does not guarantee the accuracy of the information presented at these sites.
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https://lccn.loc.gov/2016021518
http://mheducation.com/highered
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Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6 Chapter 7 Chapter 8 Chapter 9 Chapter 10 Chapter 11 Chapter 12
Brief Contents
Don’t Believe Everything You Think 1 Two Kinds of Reasoning 32 Clear Thinking, Critical Thinking, and Clear Writing 64 Credibility 93 Rhetoric, the Art of Persuasion 132 Relevance (Red Herring) Fallacies 173 Induction Fallacies 195 Formal Fallacies and Fallacies of Language 220 Deductive Arguments I: Categorical Logic 242 Deductive Arguments II: Truth-Functional Logic 284 Inductive Reasoning 338 Moral, Legal, and Aesthetic Reasoning 390
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Chapter 1
Chapter 2
Contents Preface xiv
Acknowledgments xx
About the Authors xxiv
Don’t Believe Everything You Think 1
Beliefs and Claims 4
Objective Claims and Subjective Claims 4
Fact and Opinion 5
Relativism 6
Moral Subjectivism 6
Issues 6
Arguments 7
Cognitive Biases 14
Truth and Knowledge 20
What Critical Thinking Can and Can’t Do 20
A Word About the Exercises 21
Recap 21
Additional Exercises 23
Two Kinds of Reasoning 32
Arguments: General Features 32
Conclusions Used as Premises 33
Unstated Premises and Conclusions 33
Two Kinds of Arguments 34
Deductive Arguments 34
Inductive Arguments 36
Chapter 3
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Beyond a Reasonable Doubt 37
Telling the Difference Between Deductive and Inductive Arguments 37
Deduction, Induction, and Unstated Premises 38
Balance of Considerations 40
Inference to the Best Explanation (IBE) 41
What Are Not Premises, Conclusions, or Arguments 41
Pictures 42
If . . . then . . . Sentences 42
Lists of Facts 42
“A because B” 43
Ethos, Pathos, and Logos 43
Techniques for Understanding Arguments 48
Clarifying an Argument’s Structure 49
Distinguishing Arguments from Window Dressing 51
Evaluating Arguments 52
Recap 52
Additional Exercises 53
Clear Thinking, Critical Thinking, and Clear
Writing 64
Vagueness 65
Ambiguity 67
Semantic Ambiguity 68
Grouping Ambiguity 68
Syntactic Ambiguity 68
Generality 70
Defining Terms 75
Purposes of Definitions 75
Kinds of Definitions 76
Tips on Definitions 77
Writing Argumentative Essays 79
Good Writing Practices 80
Essay Types to Avoid 81
Chapter 4
Chapter 5
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Persuasive Writing 82
Writing in a Diverse Society 82
Recap 83
Additional Exercises 84
Credibility 93
The Claim and Its Source 95
Assessing the Content of the Claim 96
Does the Claim Conflict with Our Personal Observations? 96
Does the Claim Conflict with Our Background Information? 99
The Credibility of Sources 102
Interested Parties 102
Physical and Other Characteristics 103
Expertise 105
Credibility and the News Media 109
Consolidation of Media Ownership 109
Government Management of the News 109
Bias Within the Media 111
Talk Radio 113
Advocacy Television 113
The Internet, Generally 114
Blogs 117
Advertising 118
Three Kinds of Ads 118
Recap 121
Additional Exercises 122
Rhetoric, the Art of Persuasion 132
Rhetorical Force 133
Rhetorical Devices I 134
Euphemisms and Dysphemisms 134
Weaselers 134
Downplayers 135
Chapter 6
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Rhetorical Devices II 137
Stereotypes 137
Innuendo 138
Loaded Questions 139
Rhetorical Devices III 141
Ridicule/Sarcasm 141
Hyperbole 141
Rhetorical Devices IV 142
Rhetorical Definitions and Rhetorical Explanations 142
Rhetorical Analogies and Misleading Comparisons 143
Proof Surrogates and Repetition 147
Proof Surrogates 147
Repetition 148
Persuasion Through Visual Imagery 150
The Extreme Rhetoric of Demagoguery 152
Recap 155
Additional Exercises 156
Relevance (Red Herring) Fallacies 173
Argumentum Ad Hominem 174
Poisoning the Well 175
Guilt by Association 175
Genetic Fallacy 175
Straw Man 176
False Dilemma (Ignoring Other Alternatives) 177
The Perfectionist Fallacy 178
The Line-Drawing Fallacy 178
Misplacing the Burden of Proof 179
Begging the Question (Assuming What You are Trying to Prove) 181
Appeal To Emotion 182
Argument from Outrage 182
Scare Tactics 182
Appeal to Pity 184
Chapter 7
Chapter 8
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Other Appeals to Emotion 184
Irrelevant Conclusion 186
Recap 188
Exercises 188
Induction Fallacies 195
Generalizations 195
Generalizing from Too Few Cases (Hasty Generalization) 196
Generalizing from Exceptional Cases 198
Accident 199
Weak Analogy 200
Mistaken Appeal to Authority 202
Mistaken Appeal to Popularity (Mistaken Appeal to Common Belief) 202
Mistaken Appeal to Common Practice 203
Bandwagon Fallacy 203
Fallacies Related to Cause and Effect 205
Post Hoc, Ergo Propter Hoc 205
Cum Hoc, Ergo Propter Hoc 209
Slippery Slope 211
Untestable Explanation 212
Line-Drawing Again 212
Recap 213
Exercises 213
Formal Fallacies and Fallacies of Language 220
Three Formal Fallacies: Affirming the Consequent, Denying the Antecedent,
and Undistributed Middle 220
Affirming the Consequent 220
Denying the Antecedent 221
The Undistributed Middle 222
The Fallacies of Equivocation and Amphiboly 224
The Fallacies of Composition and Division 225
Confusing Explanations with Excuses 227
Chapter 9
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Confusing Contraries and Contradictories 229
Consistency and Inconsistency 230
Miscalculating Probabilities 231
Incorrectly Combining the Probability of Independent Events 231
Gambler’s Fallacy 232
Overlooking Prior Probabilities 233
Faulty Inductive Conversion 233
Recap 235
Additional Exercises 236
Deductive Arguments I: Categorical Logic 242
Categorical Claims 244
Venn Diagrams 245
Translation into Standard Form (Introduction) 246
Translating Claims in Which the Word “Only” or the Phrase “The
Only” Occurs 246
Translating Claims About Times and Places 247
Translating Claims About Specific Individuals 249
Translating Claims that Use Mass Nouns 250
The Square of Opposition 252
Existential Assumption and the Square of Opposition 252
Inferences Across the Square 253
Three Categorical Relations 254
Conversion 254
Obversion 254
Contraposition 255
Categorical Syllogisms 262
The Venn Diagram Method of Testing for Validity 264
Existential Assumption in Categorical Syllogisms 267
Categorical Syllogisms with Unstated Premises 267
Real-Life Syllogisms 268
The Rules Method of Testing for Validity 272
Recap 274
Chapter 10
Chapter 11
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Additional Exercises 274
Deductive Arguments II: Truth-Functional Logic
284
Truth Tables and Logical Symbols 285
Claim Variables 285
Truth Tables 285
Symbolizing Compound Claims 291
“If” and “Only If” 292
Necessary and Sufficient Conditions 294
“Unless” 295
“Either . . . Or” 295
Truth-Functional Argument Patterns (Brief Version) 298
Three Common Valid Argument Patterns 298
Three Mistakes: Invalid Argument Forms 302
Truth-Functional Arguments (Full Version) 305
The Truth-Table Method 305
The Short Truth-Table Method 308
Deductions 313
Group I Rules: Elementary Valid Argument Patterns 314
Group II Rules: Truth-Functional Equivalences 319
Conditional Proof 327
Recap 330
Additional Exercises 330
Inductive Reasoning 338
Argument from Analogy 338
Evaluation of Arguments from Analogy 339
Three Arguments from Analogy 341
Other Uses of Analogy 342
Generalizing from a Sample 347
Evaluation of Arguments That Generalize from a Sample 348
Three Arguments That Generalize from a Sample 349
Chapter 12
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Scientific Generalizing from a Sample 350
The Statistical Syllogism 351
Causal Statements And Their Support 359
Forming Causal Hypotheses 359
Weighing Evidence 361
Confirming Causal Hypotheses 372
Calculating Statistical Probabilities 377
Joint Occurrence of Independent Events 377
Alternative Occurrences 377
Expectation Value 378
Calculating Conditional Probabilities 379
Causation in the Law 380
Recap 381
Additional Exercises 382
Moral, Legal, and Aesthetic Reasoning 390
Value Judgments 391
Moral Versus Nonmoral 392
Two Principles of Moral Reasoning 392
Moral Principles 394
Deriving Specific Moral Value Judgments 394
Major Perspectives in Moral Reasoning 397
Consequentialism 397
Duty Theory/Deontologism 398
Moral Relativism 400
Religious Relativism 402
Religious Absolutism 402
Virtue Ethics 402
Moral Deliberation 405
Legal Reasoning 410
Justifying Laws: Four Perspectives 411
Aesthetic Reasoning 414
Eight Aesthetic Principles 414
Using Aesthetic Principles to Judge Aesthetic Value 417
Evaluating Aesthetic Criticism: Relevance and Truth 419
Why Reason Aesthetically? 420
Recap 422
Additional Exercises 423
Appendix: Exercises from Previous Editions 426
Glossary 450
Answers, Suggestions, and Tips for Triangle Exercises 459
Credits 482
Index 483
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Critical Thinking . . . Skills for the course. Skills for life.
More Engaging
Moore & Parker are known for fresh and lively writing. They rely on their own classroom experience and on feedback from instructors in getting the correct balance between explication and example.
Examples and exercises are drawn from today’s headlines. Students learn to apply critical thinking skills to situations in a wide variety of areas: advertising, politics, the media, popular culture. I love the sense of humor of the authors, the very clear and elegant way they
make critical thinking come alive with visuals, exercises and stories. —Gary John, Richland College
[Before reading this chapter] most students don’t realize the extent of product
placement and other similar attempts at subtle manipulation. —Christian Blum, Bryant & Stratton, Buffalo
More Relevant
Moore & Parker spark student interest in skills that will serve them throughout their lives, making the study of critical thinking a meaningful endeavor.
Boxes show students how critical thinking skills are relevant to their day-to-day lives. Striking visuals in every chapter show students how images affect our judgment and shape our thinking.
The variety [in the exercises] was outstanding. [They] will provide ample opportunity for the students to put into practice the various
logical principles being discussed. —Ray Darr, Southern Illinois University
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More Student Success
Moore & Parker provide a path to student success, making students active participants in their own learning while teaching skills they can apply in all their courses.
Learning objectives link to chapter sections and in turn to print and online activities, so that students can immediately assess their mastery of the learning objective.
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Exercises are dispersed throughout most chapters, so that they link tightly with the concepts as they are presented. Students have access to over 2,000 exercises that provide practice in applying their skills.
Hands-on, practical, and one might say, even “patient” with the students’ learning as it emphatically repeats concepts and slowly progresses them step by
step through the process. —Patricia Baldwin, Pitt Community College
There are a lot of exercises, which provides nice flexibility. The . . . mix of
relatively easy and more challenging pieces . . . is useful in providing some flexibility for
working in class. —Dennis Weiss, York College of Pennsylvania
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Changes to the 12th Edition
aving arrived at an even dozen editions, we still have our original goal constantly in mind: helping teach students to think and reason critically and make better decisions and making life a bit easier for instructors of critical
thinking courses. We invite both students and instructors to get in touch with us with any ideas they have that might help us pursue these goals.
As usual, this edition updates names and events in examples and exercises in the hope that they will be familiar to the current crop of students. As we’ve mentioned before, what to many of us instructors are recent events are obscure history to many new freshmen. Other changes are as follows.
CHAPTER-SPECIFIC CHANGES
Chapter 1 begins with a fuller accounting of what we take critical thinking to be. It also goes into a bit more depth regarding cognitive biases that affect our thinking. Chapter 2 contains a revised section on inference to the best explanation (IBE). Chapter 3 is somewhat leaner, but still makes a wealth of points about the important concepts of vagueness and generality and it contains a revised account of several types of definitions. Chapter 4 gets the usual updating here and there plus a new section on credibility in social media.
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Chapter 5 gets updating, new photos, and a subsection on significant mention under the innuendo heading. Chapter 6 is left largely unchanged aside from some new examples and photos. Chapter 7 is also much the same as the previous version, although “fallacious” appeals have been changed to “mistaken” appeals; why use a word students have trouble spelling when there is one they don’t? Chapter 8 was new in the previous edition. It gets updated this time around, including a replacement of the section entitled “Overlooking False Positives” with an easier to understand “Faulty Inductive Conversion” section. Chapter 9 gets a bit of reformatting to make examples stand out more easily. Also, existential assumption gets its own subsection so it will be more difficult to miss.
Chapter 10 now makes the electrical circuit box a bit less distracting and adds a couple of new exercises to aid in learning to symbolize claims. But the biggest change from the previous edition is the reinsertion of a section that gives a briefer version of truth-functional arguments. This allows an instructor (like Moore) to deal quickly with this subject or (like Parker) to deal with it in much more detail by going on to the longer treatment that completes the chapter. Chapter 11 has the sections on analogies and generalizations fine-tuned, while the section on causal hypotheses remains in its previous pristine form. Chapter 12 has been left alone aside from a bit of updating of examples.
■ Vladimir Putin asks Hillary Clinton if she can get him a copy of Moore/Parker.
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W Acknowledgments
e, Moore and Parker, feel about this textbook the way people usually feel about their children. It has been a wonderful thing to watch it grow up through these (now) dozen editions, although it has caused us the occasional
pain in the backside along the way. Those pains—often in the form of criticism in reviews and correspondence from adopters—have usually been growing pains, however, and they have contributed to the improvement of the book. We are pretty pleased with the book, as proud parents are wont to be, but we realize that there are always things—smaller and smaller things, we hope—that can be changed for the better. We hope this edition incorporates changes of just that sort. Many of them are listed below.
The online accompaniment to the text continues to expand and, we trust, become more and more useful to adopters and their students. The preceding pages briefly describe LearnSmart and Connect, the principal components of the online material. These programs promise help for the student and an easier and more productive time for the instructor. We hope you find they live up to this promise.
Having escaped from the mysterious clutches of Mark Georgiev, former KGB operative and our editor a couple of editions ago, we have been blessed by guidance this time around from the gentle hands of Penina Braffman, Brand Manager; Anthony McHugh, Product Developer; Jane Mohr, Content Project Manager; as well as Erin Guendelsberger, Reshmi Rajeesh, and the ansrsource team, Development Editors, who encourage us even when we don’t quite toe the McGraw-Hill line.
The guidance of the following reviewers of current and previous editions and others who have written to us has been invaluable:
Keith Abney, California Polytechnic State University, San Luis Obispo James Anderson, San Diego State University Benjamin Arah, Bowie State University Sheldon Bachus Patricia Baldwin, Pitt Community College Monique Bindra Tim Black, California State University, Northridge Charles Blatz, University of Toledo
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Christian Blum, Bryant & Stratton, Buffalo K. D. Borcoman, Coastline College/CSUDH Keith Brown, California State University, East Bay Rosalie Brown Lee Carter, Glendale Community College Jennifer Caseldine-Bracht, Indiana University-Purdue University, Fort Wayne Lynne Chandler-Garcia, Pikes Peak Community College David Connelly Anne D’Arcy, California State University, Chico Michelle Darnelle, Fayetteville State University Ray Darr, Southern Illinois University, Edwardsville William J. Devlin, Bridgewater State University Paul Dickey, Metropolitan Community College Sandra Dwyer, Georgia State University Jeffrey Easlick, Saginaw Valley State University Aaron Edlin, University of California, Berkeley Dorothy Edlin Noel Edlin Ellery Eells, University of Wisconsin–Madison Ben Eggleston, University of Kansas Geoffrey B. Frasz, Community College of Southern Nevada Josh Fulcher Rory Goggins Geoffrey Gorham, University of Wisconsin–Eau Claire Joseph Graves, North Carolina A&T University Dabney Gray, Stillman College Patricia Hammer, Delta College Anthony Hanson, De Anza College Rebecca Hendricks Judith M. Hill, Saginaw Valley State University Steven Hoeltzel, James Madison University Steven R. Huizenga, Central Ohio Technical College J. F. Humphrey, North Carolina A&T University Amro Jayousi Gary John, Richland College Sunghyun Jung Allyn Kahn, Champlain College David Kelsey, Coastline Community College David Keyt, University of Washington
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Paulina Kohan William Krieger, California State University–Pomona Michael LaBossiere, Florida A&M University Sunita Lanka, Hartnell College Bill Lawson Marisha Lecea, Western Michigan University Marion Ledwig, University of Nevada–Las Vegas Vern Lee, University of Phoenix Terrance MacMullon, Eastern Washington University Andrew Magrath, Kent State University Alistair Moles, Sierra College Ralph J. Moore, Jr. Jeffry Norby, Northcentral Technical College Eric Parkinson, Syracuse University Steven Patterson, Marygrove College Carmel Phelan, College of Southern Nevada Jamie L. Phillips, Clarion University Domenick Pinto, Sacred Heart University Ayaz Pirani, Hartnell College Ed Pluth, California State University, Chico Scott Rappold, Our Lady of Holy Cross College N. Mark Rauls, College of Southern Nevada Victor Reppert, Glendale Community College Matthew E. Roberts, Patrick Henry College Greg Sadler, Fayetteville State University Matt Schulte, Montgomery College Richard Scott, Glendale Community College Laurel Severino, Santa Fe Community College Mehul Shah, Bergen Community College Robert Shanab, University of Nevada at Las Vegas Steven Silveria Robert Skipper, St. Mary’s University Aeon J. Skoble, Bridgewater State University Taggart Smith, Purdue University–Calumet Richard Sneed, University of Central Oklahoma Alan Soble, Drexel University Chris Soutter James Stump, Bethel College Lou Suarez
Susan Vineberg, Wayne State University Michael Ventimiglia, Sacred Heart University Helmut Wautischer, Sonoma State University Dennis Weiss, York College of Pennsylvania Linda L. Williams, Kent State University Amy Goodman Wilson, Webster University Christine Wolf Wayne Yuen, Ohlone College Marie G. Zaccaria, Georgia Perimeter College
Over the years, our Chico State colleague Anne Morrissey has given us more usable material than anybody else. She’s also given us more unusable material, but never mind. We’ve also had fine suggestions and examples from Curtis Peldo of Chico State and Butte College; Dan Barnett, also of Butte College, has helped in many ways over the years.
We thank colleagues at Chico State, who are ever ready with a suggestion, idea, or constructive criticism; in particular, Marcel Daguerre, Randy Larsen, Becky White, Wai-hung Wong, Zanja Yudell, and Greg Tropea, whose death in 2010 left us saddened beyond words. Greg was a dear friend whose deep wisdom and quiet insight contributed significantly to our thinking over the course of many years. We are also grateful to Bangs Tapscott, Linda Kaye Bomstad, Ann Bykerk-Kauffman, Sue Patterson, and Jeffrey Ridenour for contributions both archival and recent.
Last, and especially, we give thanks to two people who put up with us with patience, encouragement, and grace, Leah Blum and Marianne Moore.
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N A Note to Our Colleagues
o surprise, reading a book (or taking a course) in critical thinking won’t make anyone a genius. It won’t tell you who to vote for or whether to believe in God or whether to contribute to the Humane Society, But it can, we hope, help
students tell whether a given reason for doing or not doing one of those things is a good reason. It can help them spot irrelevancies in a discussion, emotional appeals, empty rhetoric, and bogus argument. Other courses can do these things too, of course. But speaking generally, other courses are probably not focused so intensely on those things.
There are differences about how best to go about teaching critical thinking. One of us, Parker likes to emphasize formal logic. Moore, not quite so much. One thing Moore and Parker both agree on, and possibly so do many instructors, is that drill and practice are essential to improving students’ critical thinking ability. And one thing we have found is that technology can be helpful in this regard. The personalized digital reading experience of this text (called SmartBook) questions students as they read, and the credit they get depends on the proportion of the questions they answer correctly. (We instructors can also see how long they spent on a reading assignment.) Additionally, Connect, McGraw-Hill’s assignment and assessment platform through which SmartBook is accessed, gives us the means to put a whole lot of exercises online. And these two things enable us to do even more drilling in class.
If you don’t use Connect or LearnSmart, this text contains hundreds and hundreds and hundreds of exercises of the sort (we think) that can be applied directly to the world at large. And they are all answered in the Instructor’s Manual. The explanatory material found in the text is (we hope) both concise and fairly readable for even first-year university students.
If you use this text or the online peripherals, we would appreciate hearing from you. We both can be contacted through McGraw-Hill Education, or via the philosophy department at Chico State.
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B About the Authors
rooke Moore and Richard Parker have taught philosophy at California State University, Chico, for almost as long as they can remember. Moore has been that university’s Outstanding Professor, and both he and Parker have received
top academic honors on their campus. Moore has seen several terms as department chair, and Parker has served as chair of the academic senate and dean of undergraduate education.
Moore has a bachelor’s degree in music from Antioch College and a PhD in philosophy from the University of Cincinnati; Parker did his undergraduate degree at the University of Arkansas and his PhD at the University of Washington, both in philosophy.
Moore has finally given up being the world’s most serious amateur volleyball player. He and Marianne share their house and life with Sparky, as cute a pup as you’ll ever see. He has never sold an automobile.
Parker gets around in a 1962 MG or on a Harley softail. He plays golf for fun, shoots pool for money, and plays guitar for a semiprofessional flamenco troupe. He lives with Djobi, a hundred-pound Doberman.
Moore and Parker have remained steadfast friends through it all. They are never mistaken for one another.
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To: Sherry and Bill; and Sydney, Darby, Alexander and Levi Peyton Elizabeth, and Griffin From Richard From Brooke
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This is not entirely a work of nonfiction.
1. 2. 3. 4. 5.
6.
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1 Don’t Believe Everything You Think
Students will learn to . . .
Define critical thinking Explain the role of beliefs and claims in critical thinking Identify issues in real-world situations Recognize an argument Define and identify the common cognitive biases that affect critical thinking Understand the terms “truth” and “knowledge” as used in this book
little before noon on December 14, 2015, a man wearing a black stocking cap, black gloves, and a green sweat shirt with a four-leaf clover and the words “Get Lucky” printed on the front entered the Sterling State Bank in
Rochester, Minnesota.* He demanded cash and gave the teller a note saying he was armed. Police officers arrived and followed the man’s tracks in the snow to the parking lot of a Comfort Inn nearby, but by then the man had driven off in a car.
The next day, a reporter from KIMT-TV had set up in front of the bank to
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update the story, and right then and there the same man tried to rob the same bank again. When the teller saw the man he yelled out, “That’s the robber!” and the reporter called the police. This time when the police followed the suspect’s footprints they spotted his vehicle and apprehended him.
Now, educators will disagree about what exactly critical thinking is, but there will be no disputing that, whatever it is, “Get Lucky” wasn’t doing it. First of all, robbing banks isn’t necessarily the best way to make a living. But if you insist on robbing a bank, then probably you don’t want to leave footprints to your car, and probably you don’t want to try to rob the bank when a TV crew is filming it. Among other things, critical thinking involves considering the possible outcomes of an action.
Among what other things? Speaking generally, if we just think or do stuff, that’s not thinking critically. Critical thinking kicks in when we evaluate beliefs and actions—when we critique them. On the one hand, there is good, old- fashioned thinking. That’s what we do when we form opinions, make judgments, arrive at decisions, develop plans, come to conclusions, offer hypotheses, and the like. On the other hand, there is critical thinking. That’s what we do when we rationally evaluate the first kind of thinking. Critical thinking is thinking that critiques. It involves critiquing opinions, judgments, decisions, plans, conclusions, and reasoning in general. We engage in it when we consider whether our thinking (or someone else’s) abides by the criteria of good sense and logic.
If you are taking other courses, chances are your instructor will think critically about the work you turn in. He or she will offer critical commentary on what you submit. If you want to think critically, you have to do this yourself to your own work. Try to leave your instructor with nothing to say except, “Good job!”
It can be the same in the workplace or in the military. You might perhaps be asked to solve a problem or troubleshoot a situation or come up with a recommendation, or any number of other things that involve arriving at conclusions. Your colleagues or friends or supervisors may give you feedback or commentary. They are thinking critically about your reasoning.
Of course, if you are so brilliant that you never err in your thinking, then you may not need feedback from others. Unfortunately, there is evidence that people who think they are experts are more likely to believe they know things they don’t really know.* Anyway, almost everyone makes mistakes. We overlook important considerations, ignore viewpoints that conflict with our own, or in other ways don’t think as clearly as we might. Most of us benefit from a little critical commentary, and this includes commentary that comes from ourselves. The chances of reaching defensible conclusions improve if we don’t simply conclude willy-nilly, but reflect on our
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reasoning and try to make certain it is sound. Being able to think critically can be useful in another way. Others try to influence
what we think and do. There is much to be said for being able to critically evaluate a sales pitch, whether it comes from a stranger or a friend, or is about kitchen gadgets or for whom to vote for president. Critical thinking helps us recognize a scam when we see it.
Some educators equate critical thinking with problem solving or innovative thinking (“thinking outside the box”). This is fine, though at a certain point proposed solutions and possible innovations have to be tested. That’s where critical thinking comes in.
This is a book in critical thinking because it offers guidance about critiquing thinking. The book and the course you are using it in, if you are, explain the minimum criteria of good reasoning—the requirements a piece of reasoning must meet if it is worth paying attention to, no matter what the context. Along the way we will explore the most common and important obstacles to good reasoning, as well as some of the most common mistakes people make when coming to conclusions. Other courses you take offer refinements. In them you will learn what considerations are important from the perspective of individual disciplines. But in no course anywhere, at least in no course that involves arriving at conclusions, will thinking that violates the standards set forth in this book be accepted.
If it does nothing else, what you read here and learn in your critical thinking course should help you avoid at least a few of the more egregious common errors people make when they reason. If you would have otherwise made these mistakes, you will have become smarter. Not smarter in some particular subject, mind you, but smarter in general. The things you learn from this book (and from the course you may be reading it for) apply to nearly any subject people can talk or think or write about.
To a certain extent, questions we should ask when critiquing our own—or someone else’s—thinking depend on what is at issue. Deciding whom to vote for, whether to buy a house, whether a mathematical proof is sound, which toothpaste to buy, or what kind of dog to get involve different considerations. In all cases, however, we should want to avoid making or accepting weak and invalid arguments. We should also avoid being distracted by irrelevancies or ruled by emotion, succumbing to fallacies or bias, and being influenced by dubious authority or half-baked speculation. These are not the only criteria by which reasoning might be evaluated, but they are central and important, and they provide the main focus of this book.
Critical Thinking, the Long Version
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The Collegiate Learning Assessment (CLA) Project of the Council for Aid to Education has come up with a list of skills that covers almost everything your authors believe is important in critical thinking. If you achieve mastery over all these or even a significant majority of them, you’ll be well ahead of most of your peers—and your fellow citizens. In question form, here is what the council came up with:
How well does the student determine what information is or is not pertinent; distinguish between rational claims and emotional ones; separate fact from opinion; recognize the ways in which evidence might be limited or compromised; spot deception and holes in the arguments of others; present his/her own analysis of the data or information; recognize logical flaws in arguments; draw connections between discrete sources of data and information; attend to contradictory, inadequate, or ambiguous information; construct cogent arguments rooted in data rather than opinion; select the strongest set of supporting data; avoid overstated conclusions; identify holes in the evidence and suggest additional information to collect; recognize that a problem may have no clear answer or single solution; propose other options and weigh them in the decision; consider all stakeholders or affected parties in suggesting a course of action; articulate the argument and the context for that argument;
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correctly and precisely use evidence to defend the argument; logically and cohesively organize the argument; avoid extraneous elements in an argument’s development; present evidence in an order that contributes to a persuasive argument?
_______________ www.aacu.org/peerreview/pr_sp07_analysis1.cfm.
BELIEFS AND CLAIMS
Why bother thinking critically? The ultimate objective in thinking critically is to come to conclusions that are correct and to make decisions that are wise. Because our decisions reflect our conclusions, we can simplify things by saying that the purpose of thinking critically is to come to correct conclusions. The method used to achieve this objective is to evaluate our thinking by the standards of rationality. Of course, we can also evaluate someone else’s thinking, though the objective there might simply be to help the person.
■ The judges on The Voice critique singers, but that doesn’t automatically qualify as thinking critically.
http://www.aacu.org/peerreview/pr_sp07_analysis1.cfm
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When we come to a conclusion, we have a belief. Concluding involves believing. If you conclude the battery is dead, you believe the battery is dead. Keeping this in mind, let’s define a few key terms.
A belief is, obviously, something you believe. It is important to understand that a belief is propositional, which means it can be expressed in a declarative sentence—a sentence that is either true or false. A good bit of muddleheaded thinking can be avoided if you understand that beliefs are propositional entities, but more on this later.
As we use these words, beliefs are the same as judgments and opinions. When we express a belief (or judgment or opinion) in a declarative sentence, the result is a statement or claim or assertion, and for our purposes these are the same thing. Claims can be used for other purposes than to state beliefs, but this is the use we’re primarily concerned with.
Beliefs and claims are propositional: they can be expressed in true-or-false declarative sentences.
Objective Claims and Subjective Claims
Before we say something more about conclusions, we should make a distinction between objective and subjective claims. An objective claim has this characteristic: whether it is true or false is independent of whether people think it is true or false. “There is life on Mars” is thus an objective claim, because whether or not life exists there doesn’t depend on whether people think it does. If everyone suddenly believed there is life on Mars, that doesn’t mean that suddenly there would be life on Mars. Likewise, “God exists” is an objective claim because whether it is true doesn’t depend on whether people think it is true.
Although objective claims are either true or false, we may not know which a given
■ That could be you under the snow if you don’t think critically.
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claim is. “Portland, Oregon, is closer to the North Pole than to the equator” is a true objective claim. “Portland, Oregon, is closer to the equator than to the North Pole” is a false objective claim. “More stamp collectors live in Portland, Oregon, than in Portland, Maine” is an objective claim whose truth or falsity is not known, at least not by us.
Not every claim is objective, of course. “Bruno Mars has swag” is not objective, for it lacks the characteristic mentioned previously. That is, whether or not someone has swag does depend on whether people think he does. If nobody thinks Bruno Mars has swag, then he doesn’t. If Parker thinks he does and Moore doesn’t, you will say that Parker and Moore are each entitled to their opinions. Whether someone has swag is in the eyes of the beholder.
Claims of this variety are subjective. Whether a subjective claim is true or false is not independent of whether people think it is true or false. Examples of subjective claims would be judgments of taste, such as “Rice vinegar is too sweet.” Is rice vinegar too sweet? It depends on what you think. Some kinds of comparisons also are subjective. Is snowboarding more fun than skiing? Again, it depends on what you think, and there is no further “truth” to consider. However, many statements contain both objective and nonobjective elements, as in “Somebody stole our nifty concrete lawn duck.” Whether the lawn duck is concrete is an objective question; whether it is our lawn duck is an objective question; and whether it was stolen is an objective question. But whether the stolen concrete lawn duck is nifty is a subjective question.
Fact and Opinion
Sometimes people talk about the difference between “fact” and “opinion,” having in mind the notion that all opinions are subjective. But some opinions are not subjective, because their truth or falsity is independent of what people think. Again, in this book “opinion” is just another word for “belief.” If you believe that Portland, Oregon, is closer to the North Pole than to the equator, that opinion happens to be true, and would continue to be true even if you change your mind. You can refer to objective opinions as factual opinions or beliefs, if you want—but that doesn’t mean factual opinions are all true. “Portland, Oregon, is closer to the equator than to the North Pole” is a factual opinion that is false.
Factual opinion/belief/claim = objective opinion/belief/claim = opinion/belief/claim whose truth is independent of whether anyone thinks it is true.
Thinking About Thinking
Remember, an objective statement is not made true by someone thinking it is true. “Wait a minute,” you might say. “Isn’t the statement ‘Joanie is thinking about Frank’ made true by her thinking that it is true?” The answer is no! It is made true by her thinking about Frank.
Relativism
Relativism is the idea that truth is relative to the standards of a given culture. More precisely, relativism holds that if your culture and some other culture have different standards of truth or evidence, there is no independent “God’s-eye view” by which one culture’s standards can be seen to be more correct than the others’.
Whatever may be said of this as an abstract philosophical doctrine, it cannot possibly mean that an objective statement could be made true by a culture’s thinking that it is true. If it is universally believed in some culture that “water” is not H2O, then either the people in that culture are mistaken or their word “water” does not refer to water.
Moral Subjectivism
Moral subjectivism is the idea that moral opinions, such as “Bullfighting is morally wrong” or “Jason shouldn’t lie to his parents,” are subjective. It is the idea, in other words, that if you think bullfighting is morally wrong, then it is morally wrong for you and you don’t need to consider any further truth. It is the idea expressed by Hamlet in the famous passage, “There is nothing either good or bad, but that thinking makes it so.”
You should be wary of Hamlet’s dictum. Ask yourself this: If someone actually believed there is nothing wrong with torturing donkeys or stoning women to death for adultery, would you say, well, if that’s what he thinks, then it’s fine for him to torture donkeys or stone women to death? Of course you wouldn’t. Those ideas can’t be made true by thinking they are true anymore than drinking battery acid can be made good for you by thinking it is.
ISSUES
An issue, as we employ that concept in this book, is simply a question. Is Moore taller than Parker? When we ask that question, we raise the issue as to whether Moore is taller than Parker. To put it differently, we are considering whether the claim “Moore is taller than Parker” is true. Let us note in passing that as with claims, some issues are objective. Is Moore taller than Parker? Whether he is or isn’t doesn’t depend on
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whether we think he is, so this is an objective issue (question). Other issues, such as whether P. Diddy dresses well, are subjective, in the sense
explained previously. The first order of business when it comes to thinking critically about an issue is to
determine what, exactly, the issue is. Unfortunately, in many real-life situations, it is difficult to identify exactly what the issue is—meaning it is difficult to identify exactly what claim is in question. This happens for lots of reasons, from purposeful obfuscation to ambiguous terminology to plain muddleheaded thinking. In his inaugural address President Warren G. Harding said,
We have mistaken unpreparedness to embrace it to be a challenge of the reality and due concern for making all citizens fit for participation will give added strength of citizenship and magnify our achievement.
This is formidable. Do you understand what issue Harding is addressing? Neither does anyone else, because his statement is perfectly meaningless. (American satirist H. L. Mencken described it as a “sonorous nonsense driven home with gestures.”*) Understanding what is meant by a claim has so many aspects that we’ll devote a large part of Chapter 3 to the subject.
However, if you have absolutely no clue as to what an issue actually is, there isn’t much point in considering it further—you don’t know what “it” is. There also isn’t much point in considering it further if you have no idea as to what would count toward settling it. For example, suppose someone asks, “Is there an identical you in a different dimension?” What sort of evidence would support saying either there is or isn’t? Nobody has any idea. (Almost any question about different “dimensions” or “planes” or “universes” would be apt to suffer from the same problem unless, possibly, it were to be raised from someone well educated in physics who used those concepts in a technical way.) “Is everything really one?” would also qualify as something you couldn’t begin to settle, as would wondering if “the entire universe was created instantly five minutes ago with all false memories and fictitious records.”**
Obscure issues aren’t always as metaphysical as the preceding examples. Listen carefully and you may hear more than one politician say something like, “It is human nature to desire freedom.” Oh, really? This sounds good, but if you look at it closely it’s hard to know exactly what sort of data would support the remark.
This isn’t to imply that only issues that can be settled through scientific test or via the experimental method are worth considering. Moral issues cannot be settled in that way, for example. Mathematical and historical questions are not answered by experiment, and neither are important philosophical questions. Does God exist? Is there free will? What difference does it make if he does or doesn’t or there is or isn’t?
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Legal questions, questions of aesthetics—the list of important questions not subject to purely scientific resolution is very long. The point here is merely that if a question is to be taken seriously, or if you want others to take it seriously, or if you want others who can think critically to take it seriously, you must have some idea as to what considerations bear on the answer.
ARGUMENTS
In our experience, lots of college students seriously contemplate getting a dog or cat. But they are conflicted. On the one hand, it would be sweet to have a nice pet; but on the other, it would be extra work and cost money, and they aren’t sure what to do with the animal if they take a trip.
If you are such a student, you weigh the arguments pro and con. An argument presents a consideration for accepting a claim. For example, this is an argument:
A dog would keep me company; so I should get one.
Are You Good at Reasoning?
Are you the kind of person who reasons well? Some people are. Unfortunately, maybe people who aren’t very good at reasoning are the most likely to overestimate their reasoning ability.*
And so is this:
My landlord will raise my rent; so I shouldn’t get one.
The first example is an argument for getting a dog. The second is an argument for not getting one.
As you can see from these two examples, an argument consists of two parts. One part gives a reason for accepting the other part. The part that provides the reason is called the premise of the argument,* though an argument may have more than one premise. The other part is called the conclusion. The conclusion of an argument is what the premise supposedly supports or demonstrates.
You should always think of the conclusion of an argument as stating a position on an issue, and of the premise or premises as giving reasons for taking that position.
Want an example? Look at the two arguments previously shown. They both
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address the issue of whether I should get a dog. The premise of the first example (“A dog would keep me company”) gives a reason for saying I should get a dog. The premise of the second example (“My landlord will raise my rent”) gives a reason for saying I should not get a dog.
What does this have to do with critical thinking? Everything. You want to make the best decision on an important issue—in this case, whether to get a dog. You evaluate the arguments pro and con. Being able to do this intelligently may not be the sum total of critical thinking, but it is an essential part of it.
A large part of this book is devoted to understanding how to evaluate arguments, and all this will begin in Chapter 2. However, right now, two minor points about arguments are worth noticing:
The two arguments given as examples are not very long or complicated. Some arguments can be very long and complicated. Einstein’s revolutionary theory that E = mc2 was based on complex mathematical reasoning, and that reasoning was his argument for saying that E = mc2. Not every issue requires an argument for resolution. Is your throat sore? You can just tell directly, and no argument is necessary.
We will now offer you a few exercises to help you understand these fundamental concepts. In the next section we will look at psychological factors that impede clear thought.
Exercise 1-1
Answer the questions based on your reading to this point, including the boxes.
▲—See the answers section at the back of the book. What is an argument?
T or F: A claim is what you use to state an opinion or a belief. T or F: Critical thinking consists in attacking other people’s ideas.
T or F: Whether a passage contains an argument depends on how long it is.
T or F: When a question has been asked, an issue has been raised. T or F: All arguments have a premise.
T or F: All arguments have a conclusion. T or F: You can reach a conclusion without believing it is true. T or F: Beliefs, judgments, and opinions are the same thing.
▲ 10. 11. 12.
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14. 15.
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T or F: All opinions are subjective. T or F: All factual claims are true. “There is nothing either good or bad but that thinking makes it so” expresses a doctrine known as _____________________.
The first order of business when it comes to thinking critically about an issue is (a) to determine whether the issue is subjective or objective, (b) to determine whether the issue can be resolved, or (c) to determine what exactly the issue is.
T or F: The conclusion of an argument states a position on an issue. T or F: Issues can be resolved only through scientific testing.
T or F: Statements, claims, and assertions are the same thing. T or F: The claim “Death Valley is an eyesore” expresses a subjective opinion. T or F: Every issue requires an argument for a resolution.
T or F: Relativism is the idea that if the standards of evidence or truth are different for two cultures, there is no independent way of saying which standards are the correct ones.
T or F: It is not possible to reason correctly if you do not think critically.
Exercise 1-2
On the basis of a distinction covered so far, divide these items into two groups of five items each such that all the items in one group have a feature that none of the
■ Can bears and other animals think critically? Find out by checking the answers section at the back of the book.
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items in the second group have. Describe the feature on which you based your classifications. The items that belong in one group are listed at the back of the book.
You shouldn’t buy that car because it is ugly. That car is ugly, and it costs more than $25,000, too. Rainbows have seven colors, although it’s not always easy to see them all.
Walking is the best exercise. It places the least stress on your joints.
The ocean on the central coast is the most beautiful shade of sky blue, but it gets greener as you go north. Her favorite color is yellow because it is the color of the sun.
Pooh is my favorite cartoon character because he has lots of personality. You must turn off the lights when you leave the room. They cost a lot of money to run, and you don’t need them during the day. Television programs have too much violence and immoral behavior. Hundreds of killings are portrayed every month.
You’ll be able to find a calendar on sale after the first of the year, so it is a good idea to wait until then to buy one.
Exercise 1-3
Which of the following claims are objective? Nicki Minaj can fake a great English accent.
On a baseball field, the center of the pitcher’s mound is 59 feet from home plate. Staring at the sun will damage your eyes.
Green is the most pleasant color to look at. Yellow is Jennifer’s favorite color. With enough experience, a person who doesn’t like opera can come to appreciate it.
Opera would be easier to listen to if they’d leave out the singing. Sailing is much more soothing than sputtering about in a motorboat. Driving while drowsy is dangerous.
Pit vipers can strike a warm-blooded animal even when it is pitch dark. P. Diddy is totally bink. P. Diddy is totally bink to me.
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Exercise 1-4
Which of the following are subjective? Fallon tells better jokes than Colbert.
In 2013 Miguel Cabrera hit the most home runs on a 3–0 count. Your teacher will complain if you text in class.
Your teacher would be crazy not to complain if you text in class. There is life on Mars. Golf wastes time.
Warcraft scared the you-know-what out of my sister. Warcraft is lousy. A total letdown. Movies like Warcraft lack redeeming social value. [Hint: An assertion might have more than one subjective element.]
Donald Trump has unusual hair.
Exercise 1-5
Some of these items are arguments, and some are not. Which are which? Tipsarevic is unlikely to win the U.S. Open this year. He has a nagging leg injury, plus he doesn’t have the drive he once had.
Hey there, Marco! Don’t go giving that cat top sirloin. What’s the matter with you? You got no brains? If you’ve ever met a pet bird, you know they are busy creatures.
Everybody is saying the president earned the Nobel Prize. What a stupid idea! She hasn’t earned it at all. There’s not a lick of truth in that notion.
“Is the author really entitled to assert that there is a degree of unity among these essays which makes this a book rather than a congeries? I am inclined to say that he is justified in this claim, but articulating this justification is a somewhat complex task.”
—From a book review by Stanley Bates
As a long-time customer, you’re already taking advantage of our money management expertise and variety of investment choices. That’s a good reason for consolidating your other eligible assets into an IRA with us.
PROFESSOR X: Well, I see where the new chancellor wants to increase class sizes. PROFESSOR Y: Yeah, another of his bright ideas.
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PROFESSOR X: Actually, I don’t think it hurts to have one or two extra people in class. PROFESSOR Y: What? Of course it hurts. Whatever are you thinking? PROFESSOR X: Well, I just think there are good reasons for increasing the class size a bit.
Yes, I charge a little more than other dentists. But I feel I give better service. So my billing practices are justified. Since you want to purchase the house, you should exercise your option before June 30, 2018. Otherwise, you will forfeit the option price.
John Montgomery has been the Eastern Baseball League’s best closer this season. Unfortunately, when a closer gets shelled, as Montgomery did last night, it takes him a while to recover. Nobody will say he is the best closer after that performance.
Exercise 1-6
Determine which of the following passages contain arguments. For any that do, identify the argument’s conclusion. There aren’t hard-and-fast rules for identifying arguments, so you’ll have to read closely and think carefully about some of these.
The Directory of Intentional Communities lists more than 200 groups across the country organized around a variety of purposes, including environmentally aware living.
Carl would like to help out, but he won’t be in town. We’ll have to find someone else who owns a truck. Once upon a time Washington, DC, passed an ordinance prohibiting private ownership of firearms. After that, Washington’s murder rate shot up 121 percent. Bans on firearms are clearly counterproductive.
Computers will never be able to converse intelligently through speech. A simple example proves this. The sentences “How do you recognize speech?” and “How do you wreck a nice beach?” have different meanings, but they sound similar enough that a computer could not distinguish between the two.
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The Carrie Diaries isn’t very good. It’s just a repackage of Sex and the City. “Like short-term memory, long-term memory retains information that is encoded in terms of sense modality and in terms of links with information that was learned earlier (that is, meaning).”
—Neil R. Carlson
Fears that chemicals in teething rings and soft plastic toys may cause cancer may be justified. Last week, the Consumer Product Safety Commission issued a report confirming that low amounts of DEHP, known to cause liver cancer in lab animals, may be absorbed from certain infant products.
“It may be true that people, not guns, kill people. But people with guns kill more people than people without guns. As long as the number of lethal weapons in the hands of the American people continues to grow, so will the murder rate.”
—Susan Mish’alani
Then: A Miami man gets thirty days in the stockade for wearing a flag patch on the seat of his trousers. Now: Miami department stores sell boxer trunks made up to look like an American flag. Times have changed.
Dockers are still in style, but skinny legs are no longer trending.
Exercise 1-7
■ Think you are welcome? Think again and think critically.
▲ 1.
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For each numbered passage, identify which lettered item best states the primary issue discussed in the passage. Be prepared to say why you think your choice is the correct one.
Let me tell you why Hank ought not to take that math course. First, it’s too hard, and he’ll probably flunk it. Second, he’s going to spend the whole term in a state of frustration. Third, he’ll probably get depressed and do poorly in all the rest of his courses.
whether Hank ought to take the math course whether Hank would flunk the math course whether Hank will spend the whole term in a state of frustration whether Hank will get depressed and do poorly in all the rest of his courses
The county has cut the library budget for salaried library workers, and there will not be enough volunteers to make up for the lack of paid workers. Therefore, the library will have to be open fewer hours next year.
whether the library will have to be open fewer hours next year whether there will be enough volunteers to make up for the lack of paid workers
Pollution of the waters of the Everglades and of Florida Bay is due to multiple causes. These include cattle farming, dairy farming, industry, tourism, and urban development. So it is simply not true that the sugar industry is completely responsible for the pollution of these waters.
whether pollution of the waters of the Everglades and Florida Bay is due to multiple causes whether pollution is caused by cattle farming, dairy farming, industry, tourism, and urban development whether the sugar industry is partly responsible for the pollution of these waters whether the sugar industry is completely responsible for the pollution of these waters
It’s clear that the mainstream media have lost interest in classical music. For example, the NBC network used to have its own classical orchestra conducted by Arturo Toscanini, but no such orchestra exists now. One newspaper, the no-longer-existent Washington Star, used to have thirteen classical music reviewers; that’s more than twice as many as
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The New York Times has now. H. L. Mencken and other columnists used to devote considerable space to classical music; nowadays, you almost never see it mentioned in a major column.
whether popular taste has turned away from classical music whether newspapers are employing fewer writers on classical music whether the mainstream media have lost interest in classical music
This year’s National Football League draft lists a large number of quarterbacks among its highest-ranking candidates. Furthermore, quite a number of teams do not have first-class quarterbacks. It’s therefore likely that an unusually large number of quarterbacks will be drafted early in this year’s draft.
whether teams without first-class quarterbacks will choose quarterbacks in the draft whether this year’s NFL draft includes a large number of quarterbacks whether an unusually large number of quarterbacks will be drafted early in this year’s draft
An animal that will walk out into a rainstorm and stare up at the clouds until water runs into its nostrils and it drowns—well, that’s what I call the world’s dumbest animal. And that’s exactly what young domestic turkeys do.
whether young domestic turkeys will drown themselves in the rain whether any animal is dumb enough to drown itself in the rain whether young domestic turkeys are the world’s dumbest animal
The defeat of the school voucher initiative was a bad thing for the country because now public schools won’t have any incentive to clean up their act. Furthermore, the defeat perpetuates the private-school-for-the- rich, public-school-for-the-poor syndrome.
whether public schools now have any incentive to clean up their act whether the defeat of the school voucher initiative was bad for the country whether public schools now have any incentive to clean up their act and whether the private-school-for-the-rich, public-school-for-
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the-poor syndrome will be perpetuated (issues are equally stressed)
From an editorial in a newspaper outside Southern California: “The people in Southern California who lost a fortune in the wildfires last year could have bought insurance that would have covered their houses and practically everything in them. And anybody with any foresight would have made sure there were no brush and no trees near the houses so that there would be a buffer zone between the house and any fire, as the Forest Service recommends. Finally, anybody living in a fire danger zone ought to know enough to have a fireproof or fire-resistant roof on the house. So, you see, most of the losses those people suffered were simply their own fault.”
whether fire victims could have done anything to prevent their losses whether insurance, fire buffer zones, and fire-resistant roofs could have prevented much of the loss whether the losses people suffered in the fires were their own fault
“Whatever we believe, we think agreeable to reason, and, on that account, yield our assent to it. Whatever we disbelieve, we think contrary to reason, and, on that account, dissent from it. Reason, therefore, is allowed to be the principle by which our belief and opinions ought to be regulated.”
—Thomas Reid, Essays on the Active Powers of Man
whether reason is the principle by which our beliefs and opinions ought to be regulated whether what we believe is agreeable to reason whether what we disbelieve is contrary to reason both b and c
Most people you find on university faculties are people who are interested in ideas. And the most interesting ideas are usually new ideas. So most people you find on university faculties are interested in new ideas. Therefore, you are not going to find many conservatives on university faculties, because conservatives are not usually interested in new ideas.
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whether conservatives are interested in new ideas whether you’ll find many conservatives on university faculties whether people on university faculties are interested more in new ideas than in older ideas whether most people are correct
When a poll is really, really out of whack with what I want to happen, I do have a tendency to disregard it. —Rush Limbaugh, recognizing his own confirmation bias
COGNITIVE BIASES
Unconscious features of psychology can affect human mental processes, sometimes in unexpected ways. Recent research suggests that donning formal business attire or a physician’s white lab coat might improve a person’s performance on a cognitive test.* Seeing a fast food logo (e.g., McDonald’s golden arches) may make some individuals attempt to process information more hastily.** In one experiment, subjects being told that the expensive sunglasses they were asked to wear were fake increased their propensity to cheat on tests that involved cash payments for correct answers.† In another experiment, male subjects, if dressed in sweats, made less profitable deals in simulated negotiations than did subjects dressed in suits.
Were we entirely rational, our conclusions would be grounded in logic and based on evidence objectively weighed. The unconscious features of human psychology affecting belief formation that have been reasonably well established include several that are widely referred to as cognitive biases.* They skew our apprehension of reality and interfere with our ability to think clearly, process information accurately, and reason objectively.
People will generally accept facts as truth only if the facts agree with what they already believe. —Andy Rooney, nicely explaining belief bias
For example, we tend to evaluate an argument based on whether we agree with it rather than on the criteria of logic. Is the following specimen good reasoning?
All pit bulls are dogs. Some dogs bite.
Therefore some pit bulls bite.
It isn’t. You might as well conclude some pit bulls are fox terriers. After all, all pit bulls are dogs and some dogs are fox terriers. If it took you a moment to see that the first argument is illogical, it’s because its conclusion is something you know is true.
The tendency to evaluate reasoning by the believability of its conclusion is known as belief bias. A closely related cognitive bias is confirmation bias, which refers to the tendency to attach more weight to evidence that supports our viewpoint. If you are a Democrat, you may view evidence that Fox News is biased as overwhelming; if you are a Republican you may regard the same evidence as weak and unconvincing. In science, good experiments are designed to ensure that experimenters can’t “cherry- pick” evidence, that is, search for evidence that supports the hypothesis they think is true while ignoring evidence to the contrary.
There isn’t any hard-and-fast difference between confirmation bias and belief bias; they are both unconscious expressions of the human tendency to think our side of an issue must be the correct side. Thinking critically means being especially critical of arguments that support our own points of view.
Some cognitive biases involve heuristics, general rules we unconsciously follow in estimating probabilities. An example is the availability heuristic, which involves unconsciously assigning a probability to a type of event on the basis of how often one thinks of events of that type. After watching multiple news reports of an earthquake or an airplane crash or a case of child abuse, thoughts of earthquakes and airplane crashes and child abuse will be in the front of one’s mind. Accordingly, one may overestimate their probability. True, if the probability of airplane crashes were to increase, then one might well think about airplane crashes more often; but it does not follow that if one thinks about them more often, their probability has increased.
■ Bad-mouthing someone is not the same as thinking critically about what he or she says.
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The availability heuristic may explain how easy it is to make the mistake known as generalizing from anecdote, a logical fallacy we discuss later in the book. Generalizing from anecdote happens when one accepts a sweeping generalization based on a single vivid report. The availability heuristic is also probably related to the false consensus effect, which refers to the inclination we may have to assume that our attitudes and those held by people around us are shared by society at large.*
Another source of skewed belief is the bandwagon effect, which refers to an unconscious tendency to align one’s thinking with that of other people. The bandwagon effect is potentially a powerful source of cognitive distortion. In famous experiments, psychologist Solomon Asch found that what other people say they see may actually alter what we think we see.** We—the authors—have students take tests and quizzes using smartphones and clickers, with software that instantly displays the opinion of the class in a bar graph projected on a screen. Not infrequently it happens that, if opinion begins to build for one answer, almost everyone switches to that option —even if it is incorrect or illogical.
If you have wondered why consumer products are routinely advertised as best- sellers, you now know the answer. Marketers understand the bandwagon effect. They know that getting people to believe that a product is popular generates further sales.
Political propagandists also know we have an unconscious need to align our beliefs with the opinions of other people. Thus, they try to increase support for a measure by asserting that everyone likes it, or—and this is even more effective—by asserting that nobody likes whatever the opposition has proposed. Given alternative measures X and Y, “Nobody wants X!” is even more likely to generate support for Y than is “Everyone wants Y!” This is because of negativity bias, the tendency people have to weight negative information more heavily than positive information when evaluating things. Negativity bias is hard-wired into us: the brain displays more neural activity in response to negative information than to positive information.† A corollary to negativity bias from economics is that people generally are more strongly motivated to avoid a loss than to accrue a gain, a bias known as loss aversion.
It also should come as no surprise that we find it easier to form negative opinions of people who don’t belong to our club, church, party, nationality, or other group. This is a part of in-group bias, another cognitive factor that may color perception and distort judgment. We may well perceive the members of our own group as exhibiting more variety and individuality than the members of this or that out-group, who we may view as indistinguishable from one another and as conforming to stereotypes. We may attribute the achievements of members of our own group to gumption and hard work and our failures to bad luck, whereas we may attribute their failures—those of the members of out-groups—to their personal shortcomings, while grudgingly discounting
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their achievements as mere good luck. The tendency to not appreciate that others’ behavior is as much constrained by events and circumstances as our own would be if we were in their position is known as the fundamental attribution error.††
Experiments suggest that people find it extraordinarily easy to forge group identities. When assigned to a group on the basis of something as trivial as a coin flip, subjects will immediately begin exhibiting in-group and attribution biases.* In a famous experiment in social psychology, the Robber’s Cave Experiment, twenty-two 12-year-old boys who previously hadn’t known each other were divided arbitrarily into two groups. When the two groups were forced to compete, the members of each group instantly exhibited hostility and other indicators of in-group bias toward the members of the other group.**
Rational Choice?
Critical thinking is aimed at coming to correct conclusions and making wise choices or decisions. We know from everyday experience that desires, fears, personal objectives, and various emotions affect choices. As explained in the text, experimental psychologists have discovered other, more unexpected and surprising, influences on our thinking.
In a recent experiment, researchers at Yale and Harvard Universities asked subjects to evaluate a job candidate by reading an applicant’s résumé, which had been attached to a clipboard. Some of the clipboards weighed ¾ pound; the others weighed 4½ pounds. Subjects holding the heavier clipboard rated the applicant as better overall. Evidently a “rational evaluation” of a person’s qualifications may be affected by irrelevant physical cues.*
People make snap judgments about who is and who is not a member of their group. Students transferring into a new high school are branded swiftly. Once, one of the authors and his wife were walking their dogs, not necessarily the world’s best- behaved pooches, along a street in Carmel, an affluent town on California’s central coast. When the author fell a few paces behind his wife, a well-dressed woman walked by and glanced disapprovingly at the dogs. “Did you see that woman?” she asked indignantly, unaware that she was referring to the wife of the man she was addressing. “You can tell she isn’t from around here,” she said. She seems to have assumed that the
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author was from the Carmel in-group, simply because he wasn’t connected to the misbehaving dogs.
In a series of famous experiments in the 1960s regarding obedience to authority, psychologist Stanley Milgram discovered that a frightening percentage of ordinary men and women will administer apparently lethal electrical shocks to innocent people, when told to do so by an experimenter in a white coat.† The findings are subject to multiple interpretations and explanations, but the tendency of humans to obey authority simply for the sake of doing so hardly needs experimental confirmation. Not long ago French researchers created a fake TV game show that was much like the Milgram experiment. The host instructed contestants to deliver electrical shocks to an individual who was said to be just another contestant, but who in reality was an actor. The contestants complied—and delivered shocks right up to a level that (if the shock was really being delivered) might execute the man. Whether the subjects were blindly following the instructions of an authority or were responding to some other impulse isn’t completely clear, but it is impossible to think that good judgment or rational thought would lead them to such excess.*
Yet another possible source of psychological distortion is the overconfidence effect, one of several self-deception biases that may be found in a variety of contexts.** If a person estimates the percentage of his or her correct answers on a subject, the estimate will likely err on the high side—at least if the questions are difficult or the subject matter is unfamiliar.† Perhaps some manifestation of the overconfidence effect explains why, in the early stages of the American Idol competition, many contestants appear totally convinced they will be crowned the next American Idol—and are speechless when the judges inform them they cannot so much as carry a tune.††
Closely related to the overconfidence effect is the better-than-average illusion. The illusion crops up when most of a group rate themselves as better than
■ Does Kanye West dress well? The issue is subjective, or, as some people say, “a matter of opinion.”
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most of the group relative to some desirable characteristic, such as resourcefulness or driving ability. The classic illustration is the 1976 survey of SAT takers, in which well over 50 percent of the respondents rated themselves as better than 50 percent of other SAT takers with respect to such qualities as leadership ability.‡ The same effect has been observed when people estimate how their intelligence, memory, or job performance stacks up with the intelligence, memory, and job performances of other members of their profession or workplace. In our own informal surveys, more than 80 percent of our students rate themselves in the top 10 percent of their class with respect to their ability to think critically.
Unfortunately, evidence indicates that even when they are informed about the better-than-average illusion, people may still rate themselves as better than most in their ability to not be subject to it.‡‡
That beliefs are generated as much by psychology and impulse as by evidence should come as no surprise. The new car that was well beyond our means yesterday seems entirely affordable today—though our finances haven’t changed. If someone invited us to The Olive Garden we’d expect decent fare; but if they suggested we try dining at, say, The Lung Garden, we’d hesitate—even if we were told the food is identical. People will go out of their way to save $10 when buying a $25 pen, but won’t do the same to save the same amount buying a $500 suit.* Programmed into our psyches are features that distort our perception, color our judgment, and impair our ability to think objectively.
The best defense? Making it a habit to think critically—and to be especially critical of arguments and evidence that seem to accord with what we already believe.
The following exercises may help you understand the cognitive biases discussed in the previous section.
Exercise 1-8
The following questions are for thought or discussion. Your instructor may ask you to write a brief essay addressing one or more of them.
Which of the cognitive biases discussed in this section do you think you might be most subject to? Why?
Can you think of other psychological tendencies you have that might interfere with the objectivity of your thinking? For example, are you unusually generous or selfish? Think again about a student (or anyone) contemplating getting a pet. Is there a cognitive bias a person in that position might be especially prone to, when weighing the arguments on both sides?
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Explain belief bias (or confirmation bias) in your own words, and give an example of a time when you may have been subject to it.
What might you do to compensate for a bias factor you listed in questions 1 or 2 in this exercise?
Exercise 1-9
For each of the following attributes, rate yourself in comparison with other students in your class. Are you
in the top 10 percent? in the top 50 to 89 percent? in the lower 25 to 49 percent? below the top 75 percent? ability to think clearly ability to think logically ability to think critically ability to be objective ability to think creatively ability to read with comprehension ability to spot political bias in the evening news IQ
If you answered (a) or (b) about one of the preceding abilities, would you change your mind if you learned that most of the class also answered (a) or (b) about that ability? Why or why not?
Exercise 1-10
Select one of the following claims you are inclined to strongly agree or disagree with. Then produce the best argument you can think of for the opposing side. When you are finished, ask someone to read your argument and tell you honestly whether he or she thinks you have been fair and objective.
“There is (is not) a God.” “Illegal immigrants should (should not) be eligible for health care benefits.” “Handgun owners should (should not) be required to register each handgun they own.” “The words ‘under God’ should (should not) be removed from the Pledge of Allegiance.” “Sex education should (should not) be taught in public schools.”
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TRUTH AND KNOWLEDGE
At the end of the day, when we are ready to turn out the lights and go to bed, we want the conclusions we have reached through painstaking critical thinking to be true—and we want to know they are true. However, what are truth and knowledge? Through the years, many competing theories have been offered to account for their real nature, but fortunately for you, we can tell you what you need to know for this discussion without getting mired in those controversies.
As for truth, the most important thing is to understand that an objective belief or claim is either true or false in the normal, commonsense way. Truth and falsity are properties of propositional entities like beliefs, opinions, judgments, statements, claims, and the like. As mentioned previously, when any of those entities is objective, whether it is true or false does not depend on whether we think it is true or false.
You can assert a claim’s truth in a number of ways. In normal conversation, we’d take each of the following as making the same statement:
A book is on the table. It is true a book is on the table. It is a fact a book is on the table. Yes, a book is on the table.
The concept of knowledge is another that philosophers have contested at a deep, theoretical level despite a general agreement that in everyday life, we understand well enough what we mean when we say we know something.
Ordinarily, you are entitled to say you know a book is on the table, provided that (1) you believe a book is on the table, (2) you have justification for this belief in the form of an argument beyond a reasonable doubt that a book is on the table, and (3) you have no reason to suspect you are mistaken, such as that you haven’t slept for several nights or have recently taken hallucinogenic drugs. Skeptics may say it is impossible to know anything, though one wonders how they know that. Presumably, they’d have to say they’re just guessing.
WHAT CRITICAL THINKING CAN AND CAN’T DO
We think critically when we evaluate the reasoning we and others use in coming to conclusions. Perhaps this remark strikes you as restricted and narrow. A composer, for example, thinks critically when he or she tries to find the right instrumentation to introduce a musical theme. A general thinks critically when he or she defines a military objective and weighs various strategies for achieving
it. Dentists think critically when they weigh the likely duration of alternative dental repairs against a patient’s life expectancy. Mechanics think critically when they attempt to diagnose mechanical problems by listening to the sound of an engine. People in each walk of life examine considerations that are unique to them.
Yet every discipline, every walk of life, every enterprise without exception involves the two kinds of reasoning we will begin examining in the next chapter. And critical thinking anywhere can be waylaid by emotion, self-interest, wishful thinking, desire to be accepted, confirmation bias, and various other psychological propensities that come with being a human being, and that also will be considered in this book.
Thinking critically won’t necessarily tell you whether you should get a dog or whom to vote for or whether there is global warming or why your car won’t start. It can, however, help you spot bad reasoning about all these things.
A WORD ABOUT THE EXERCISES
To get good at tennis, golf, playing a musical instrument, or most other skills, you have to practice, practice, and practice more. It’s the same way with critical thinking, and that’s why we provide so many exercises. For some exercises in this book, there is no such thing as only one correct answer, just as there is no such thing as only one correct way to serve a tennis ball. Some answers, however—just like tennis serves—are better than others, and that is where your instructor comes in. In many exercises, answers you give that are different from your instructor’s are not necessarily incorrect. Still, your instructor’s answers will be well thought out, reliable, and worth your attention. We recommend taking advantage of his or her experience to improve your ability to think critically.
Answers to questions marked with a triangle are found in the answers section at the back of the book.
Recap We think critically when we evaluate reasoning used in coming to conclusions. Conclusions are beliefs; when they are expressed using true-or-false declarative sentences, they are claims (or statements or assertions). A belief (or opinion or claim or statement, etc.) whose truth is independent of whether people think it is true is objective.
An issue is simply a question. One uses an argument to establish a position on an issue; the position is the conclusion of the argument. Evaluation of arguments can be skewed by emotion, wishful thinking, self-interest, confirmation bias, and other psychological impediments to objectivity.
What follows is a more complete list of ideas explored in this chapter.
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Claim: When a belief (judgment, opinion) is asserted in a declarative sentence, the result is a claim, statement, or assertion. Objective claim vs. subjective claim: An objective claim is true or false regardless of whether people think it is true or false. Claims that lack this property are said to be subjective.
“Fact vs. opinion”: People sometimes refer to true objective claims as “facts,” and use the word “opinion” to designate any claim that is subjective. “Factual claim”: An objective claim. Saying that a claim is “factual” is not the same as saying it is true. A factual claim is simply a claim whose truth does not depend on our thinking it is true. Moral subjectivism: Moral subjectivism is the idea that moral judgments are subjective. “There is nothing either good or bad but that thinking makes it so.” Issue: A question. Argument: An argument consists of two parts—one part of which (the premise or premises) is intended to provide a reason for accepting the other part (the conclusion). “Argument”: People sometimes use this word to refer just to an argument’s premise. Arguments and issues: The conclusion of an argument states a position on the issue under consideration. Cognitive bias: A feature of human psychology that skews belief formation. The ones discussed in this chapter include the following:
Belief bias: Evaluating reasoning by how believable its conclusion is. Confirmation bias: A tendency to attach more weight to considerations that support our views. Availability heuristic: Assigning a probability to an event based on how easily or frequently it is thought of. False consensus effect: Assuming our opinions and those held by people around us are shared by society at large. Bandwagon effect: The tendency to align our beliefs with those of other people. Negativity bias: Attaching more weight to negative information than to positive information. Loss aversion: Being more strongly motivated to avoid a loss than to accrue a gain.
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In-group bias: A set of cognitive biases that make us view people who belong to our group differently from people who don’t. Fundamental attribution error: Having one understanding of the behavior of people in the in-group and another for people not in the in-group. Obedience to authority: A tendency to comply with instructions from an authority. Overconfidence effect: A cognitive bias that leads us to overestimate what percentage of our answers on a subject are correct. Better-than-average illusion: A self-deception cognitive bias that leads us to overestimate our own abilities relative to those of others.
Truth: A claim is true if it is free from error. Knowledge: If you believe something, have an argument beyond a reasonable doubt that it is so, and have no reason to think you are mistaken, you can claim you know it.
Additional Exercises Here are more exercises to help you identify objective and subjective claims, recognize arguments, identify issues, and tell when two people are addressing the same issue. In addition, you will find writing exercises as well as an exercise that will give you practice in identifying the purpose of a claim.
Exercise 1-11
Identify the conclusion of any arguments contained in the following passages. There is trouble in the Middle East, there is a recession at home, and all economic indicators are trending downward. It seems likely, then, that the only way the stock market can go is down.
Lucy is too short to reach the bottom of the sign. “Can it be established that genetic humanity is sufficient for moral humanity? I think there are very good reasons for not defining the moral community in this way.”
—Mary Anne Warren
Pornography often depicts women as servants or slaves or as otherwise
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inferior to men. In light of that, it seems reasonable to expect to find more women than men who are upset by pornography.
“My folks, who were Russian immigrants, loved the chance to vote. That’s probably why I decided that I was going to vote whenever I got the chance. I’m not sure [whom I’ll vote for], but I am going to vote. And I don’t understand people who don’t.”
—Mike Wallace
“Dynamism is a function of change. On some campuses, change is effected through nonviolent or even violent means. Although we too have had our demonstrations, change here is usually a product of discussion in the decision-making process.” —Hillary Clinton, while a student at Wellesley College in the 1960s
What does it take to make a good soap? You need good guys and bad guys, sex, babies, passion, infidelity, jealousy, hatred, and suspense. And it must all be believable. Believability is the key.
We need to make clear that sexual preference, whether chosen or genetically determined, is a private matter. It has nothing to do with an individual’s ability to make a positive contribution to society. The report card on charter schools is mixed. Some show better results than public schools, others show worse. Charter schools have this advantage when it comes to test scores: the kids attending them are more apt to have involved parents.
American Idol is history, but when you remember whose careers were launched by AI, you know it was the best talent show on TV.
Exercise 1-12
For each numbered passage in this exercise, identify which lettered item best states the primary issue discussed in the passage. Be prepared to say why you think your choice is the correct one.
In pre-civil war Spain, the influence of the Catholic Church must have been much stronger on women than on men. You can determine this by looking at the number of religious communities, such as monasteries, nunneries, and so forth. A total of about 5,000 such communities existed in 1931; 4,000 of them were female, whereas only 1,000 of them were male. This proves my point about the Church’s influence on the sexes.
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whether the Catholic Church’s influence was stronger on women than on men in pre-civil war Spain whether the speaker’s statistics really prove his point about the Church’s influence whether the figures about religious communities really have anything to do with the overall influence of the Catholic Church in Spain
Breaking Bad might have been a good series without all the profanity. But without the profanity, it would not have been believable. Those people just talk that way. If you have them speaking Shakespearean English, nobody will pay attention. Yes, like many programs with offensive features—whether it’s bad language, sex, or whatever—it will never appeal to the squeamish.
whether movies with offensive features can appeal to the squeamish whether Breaking Bad would have been entertaining without the bad language whether Breaking Bad would have been believable without the profanity whether believable programs must always have offensive features
Siri is great, but it isn’t an encyclopedia. It will tell you where the nearest Round Table is, but right now it won’t tell you how late the place is open.
whether Siri is great whether Siri has encyclopedic knowledge whether Siri will have encyclopedic knowledge whether Siri knows a lot about Round Table
From the way it tastes, you might think French roast has more caffeine in it than regular coffee, but it has less. The darker the roast, the less caffeine there is in it. I read this in Consumer Reports.
whether Consumer Reports is a good source of information about coffee whether French roast has more caffeine than regular coffee whether most people think French roast has more caffeine than regular coffee
In Miami–Dade County, Florida, schools superintendent Rudy Crew
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was inundated with complaints after a police officer used a stun gun on a six-year-old student. As a result, Crew asked the Miami–Dade police to ban the use of stun guns on elementary school children. Crew did the right thing. More than 100 deaths have been linked to tasers.
whether a police officer used a stun gun on a six-year-old student whether the superintendent did the right thing by asking the police to ban the use of stun guns on elementary school children
whether 100 deaths have been linked to tasers whether the fact that 100 deaths have been linked to tasers shows that the superintendent did the right thing when he asked the police not to use tasers on children
Letting your children surf the net is like dropping them off downtown to spend the day doing whatever they want. They’ll get in trouble.
whether letting your children off downtown to spend the day doing whatever they want will lead them into trouble whether letting your children surf the net will lead them into trouble whether restrictions should be placed on children’s activities
The winner of this year’s spelling bee is a straight-A student whose favorite subject is science, which isn’t surprising, since students interested in science learn to pay attention to details.
whether the winner of this year’s spelling bee is a straight-A student whether science students learn to pay attention to details whether learning science will improve a student’s ability to spell whether learning science teaches a student to pay attention to details none of the above
Illinois state employees, both uniformed and nonuniformed, have been serving the state without a contract or cost-of-living pay increase for years, despite the fact that legislators and the governor have accepted hefty pay increases. All public employee unions should launch an initiative to amend the Illinois constitution so that it provides compulsory binding arbitration for all uniformed and
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nonuniformed public employees, under the supervision of the state supreme court.
whether Illinois state employees have been serving the state without a contract or cost-of-living pay increase for years whether public employee unions should launch an initiative to amend the Illinois constitution so that it provides compulsory binding arbitration for all uniformed and nonuniformed public employees, under the supervision of the Illinois Supreme Court neither of the above
In 2007, the Dominican Republic banned the sale of two brands of Chinese toothpaste because they contained a toxic chemical responsible for dozens of poisoning deaths in Panama. The company that exported the toothpaste, the Danyang Household Chemical Company, defended its product. “Toothpaste is not something you’d swallow, but spit out, and so it’s totally different from something you would eat,” one company manager said. The company manager was taking a position on which issue?
whether the Danyang Household Chemical Company included toxic chemicals in its toothpaste whether Danyang Household Chemical Company toothpaste prevents cavities whether the Danyang Household Chemical Company did anything wrong by exporting its toothpaste whether China should have better product safety controls
YOU: So, what do you think of the governor? YOUR FRIEND: Not much, actually. YOU: What do you mean? Don’t you think she’s been pretty good? YOUR FRIEND: Are you serious? YOU: Well, yes. I think she’s been doing a fine job. YOUR FRIEND: Oh, come on. Weren’t you complaining about her just a few days ago?
whether your friend thinks the governor has been a good governor whether you think the governor has been a good governor whether the governor has been a good governor whether you have a good argument for thinking the governor has been a good governor
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Exercise 1-13
On what issue is the speaker taking a position in each of the following? Police brutality does not happen very often. Otherwise, it would not make headlines when it does.
We have little choice but to concentrate crime-fighting efforts on enforcement because we don’t have any idea what to do about the underlying causes of crime. A lot of people think the gender of a Supreme Court justice doesn’t matter. But with three women on the bench, cases dealing with women’s issues are handled differently.
“The point is that the existence of an independent world explains our experiences better than any known alternative. We thus have good reason to believe that the world—which seems independent of our minds —really is essentially independent of our minds.” —Theodore W. Schick Jr. and Lewis Vaughn, How to Think About Weird
Things
Sure, some hot-doggers get good grades in Bubacz’s class. But my guess is if Algernon takes it, all it’ll get him is flunked out. It’s so dumb to think sales taxes hit poor people harder than rich people. The more money you have, the more you spend; and the more you spend, the more sales taxes you pay. And rich people spend more than poor people.
If you’re going to buy a synthesizer, sign up for lessons on how to use the thing. A synthesizer won’t work for you if you don’t know how to make it work.
Intravenous drug use with nonsterile needles is one of the leading causes of the spread of AIDS. Many states passed legislation allowing officials to distribute clean needles in an effort to combat this method of infection. But in eleven states, including some of the most populous, possession of hypodermic syringes without a prescription is illegal. The laws in these foot-dragging states must be changed if we hope to end this epidemic. The best way to avoid error is to suspend judgment about everything except what is certain. Because error leads to trouble, suspending judgment is the right thing to do.
“[Readers] may learn something about their own relationship to the earth
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from a people who were true conservationists. The Indians knew that life was equated with the earth and its resources, that America was a paradise, and they could not comprehend why the intruders from the East were determined to destroy all that was Indian as well as America itself.”
—Dee Brown, Bury My Heart at Wounded Knee
Exercise 1-14
Is the second person addressing the issue raised by the first person? Example
Toilet paper looks better unwinding from the back of the spool. Get real! That is so stupid! It should unwind the other way.
Analysis Marwoof addresses the issue raised by Elmop. MR.: Next weekend, we go on standard time again. We have to set the clocks ahead. MRS.: It isn’t next weekend; it’s the weekend after. And you set the clocks back an hour.
MOORE: Getting out of Afghanistan is only going to make us vulnerable to terrorism.
PARKER: Yeah, right. You’re just saying that ’cause you don’t like Obama. SHE: You don’t give me enough help around the house. Why, you hardly ever do anything!
HE: What??? I mowed the lawn on Saturday, and I washed both of the cars on Sunday. What’s more, I clean up after dinner almost every night, and I hauled all that garden stuff to the dump. How can you say I don’t do anything? SHE: Well, you sure don’t want to hear about what I do! I do a lot more than that! HEEDLESS: When people complain about what we did in Afghanistan, they just encourage terrorists to think America won’t fight. People who complain like that ought to just shut up. CAUTIOUS: I disagree. Those people are reminding everyone it isn’t in our interest to get involved in wars abroad.
MR. RJ: If you ask me, there are too many casinos around here
ELMOP: MARWOOF:
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already. We don’t need more. MR. JR: Yeah? Well that’s a strange idea coming from you; you play the lottery all the time.
JOE FITNESS: Whoa, look at that! The chain on my bike is starting to jump around! If I don’t fix it, it’ll stop working.
COUCH POTATO: What you need is to stop worrying about it. You get too much exercise as it is. YOUNG GUY: Baseball players are better now than they were forty years ago. They eat better, have better coaching, you name it. OLD GUY: They aren’t better at all. They just seem better because they get more publicity and play with juiced equipment.
STUDENT ONE: Studying is a waste of time. Half the time, I get better grades if I don’t study.
STUDENT TWO: I’d like to hear you say that in front of your parents. PHILATELIST: Did you know that U.S. postage stamps are now being printed in Canada?
PATRIOT: What an outrage! If there is one thing that ought to be made in the United States, it’s U.S. postage stamps! PHILATELIST: Oh, c’mon. If American printing companies can’t do the work, let the Canadians have it. FIRST NEIGHBOR: See here, you have no right to make so much noise at night. I have to get up early for work. SECOND NEIGHBOR: Yeah? Well, if you have the right to let your idiot dog run loose all day long, I have the right to make noise at night.
STUDY PARTNER ONE: Let’s knock off for a while and go get pizza. We’ll function better if we eat something.
STUDY PARTNER TWO: Not one of those pizzas you like! I can’t stand anchovies.
FEMALE STUDENT: The Internet is overrated. It takes forever to find something you can actually use in an assignment.
MALE STUDENT: Listen, it takes a lot longer to drive over to the library and find a place to park. RAMON: Hey, this English course is a complete waste of time. You don’t need to know how to write anymore. DEVON: That’s ridiculous. You’re just saying that because you’re a PE major.
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CULTURALLY CHALLENGED PERSON: A concert! You think I’m going to a concert when I can be home watching football?
CULTURALLY CHALLENGED PERSON’S SPOUSE: Yes, if you want dinner this week. REPUBLICAN: I don’t think Obama’s budget requests make sense.
DEMOCRAT: You just can’t stand more taxes, can you? MOORE: I’ve seen the work of both Thomas Brothers and Vernon Construction, and I tell you, Thomas Brothers does a better job. PARKER: Listen, Thomas Brothers is the highest-priced company in the whole state. If you hire them, you’ll pay double for every part of the job.
URBANITE: The new requirements will force people off septic tanks and make them hook up to the city sewer. That’s the only way we’ll ever get the nitrates and other pollutants out of the groundwater.
SUBURBANITE: You call it a requirement, but I call it an outrage! They’re going to charge us from five to fifteen thousand dollars each to make the hookups! That’s more than anybody can afford!
CRITIC: I don’t think it’s proper to sell junk bonds without emphasizing the risk involved, but it’s especially bad to sell them to older people who are investing their entire savings.
ENTREPRENEUR: Oh, come on. There’s nothing the matter with making money. ONE HAND: What with the number of handguns and armed robberies these days, it’s hard to feel safe in your own home. THE OTHER HAND: The reason you don’t feel safe is you don’t have a handgun yourself. Criminals would rather hit a house where there’s no gun than a house where there is one.
ONE GUY: Would you look at the price they want for these computer tablets? They’re making a fortune on every one of these things!
ANOTHER: Don’t give me that. I know how big a raise you got last year— you can afford a truckload of those things!
FED UP: This city is too cold in the winter, too hot in the summer, and too dangerous all the time. I’ll be happier if I exercise my early retirement option and move to my place in Arkansas.
FRIEND: You’re nuts. You’ll be miserable if you don’t work, and if you move, you’ll be back in six months. KATIE: Hey Jennifer, I hate to say this, but you would be better off riding a bike to school.
23.
24.
▲ 25.
▲ 1. 2. 3.
▲ 4. 5.
6. ▲ 7.
8. 9.
▲ 10. 11. 12.
▲ 13.
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JENNIFER: What, this from someone who drives everywhere she goes? DEZRA: What are you thinking, mowing the lawn in your bare feet? That’s totally unsafe.
KEN: Like you never did anything you could get hurt doing? YAO: Nice thing about an iMac. It never gets viruses.
MAO: Of course you would say that; you own one. HERR üBERALLES: We spend too much on heating. We must show more fortitude. FRAU üBERALLES: But you know I get cold easily.
Exercise 1-15
Which of the following claims pertain to right/wrong, good/bad, or should/shouldn’t?
We did the right thing getting rid of Saddam. He was a sadistic tyrant. That guy is the smartest person I know. Contributing to the Humane Society is good to do.
It’s time you start thinking about somebody other than yourself! Your first duty is to your family; after that, to God and country, in that order. You know what? I always tip 15 percent.
The FBI and CIA don’t share information all that often, at least that’s what I’ve heard.
You might find the parking less expensive on the street. Help him! If the situation were reversed, he would help you.
Hip hop is better than country, any day. Rodin was a master sculptor. Whatever happened to Susan Boyle? You don’t hear about her anymore.
If we want to stop the decline in enrollments here at Chaffee, we need to give students skills they can use.
Exercise 1-16
This exercise will give you another opportunity to identify when someone is offering an argument, as distinct from doing something else.
Decide which of the lettered options serves the same kind of purpose as the original remark. Then think critically about your conclusion. Do you
a. b.
▲ 1. a. b.
2. a.
b. 3.
a. b. c.
▲ 4.
a.
b.
c. 5.
a.
b.
6. a. b.
have a reason for it? Be ready to state your reasoning in class if called on. Example
Be careful! This plate is hot. Watch out. The roads are icy. Say—why don’t you get lost?
Conclusion: The purpose of (a) is most like the purpose of the original remark. Reason: Both are arguments.
I’d expect that zipper to last about a week; it’s made of cheap plastic. The wrinkles on that dog make me think of an old man. Given Sydney’s spending habits, I doubt Adolphus will stick with her for long.
If you recharge your battery, sir, it will be almost as good as new. Purchasing one CD at the regular price would entitle you to buy an unlimited number of CDs at only $4.99. I will now serve dinner, after which you can play if you want.
To put out a really creative newsletter, you should get in touch with our technology people.
Do unto others as you would have them do unto you. To put an end to this discussion, I’ll concede your point. You’d better cut down on your smoking if you want to live longer.
GE’s profits during the first quarter were short of GE’s projections. Therefore, we can expect GE’s stock to fall sharply in the next day or so.
The senator thought what he did in private was nobody’s business but his own. The dog is very hot. Probably he would appreciate a drink of water. The dog’s coat is unusually thick. No wonder he is hot.
How was my date with your brother? Well . . . he has a great personality.
How do I like my steak? Not dripping blood like this thing you just served me. How do I like your dress? Say, did you know that black is more slimming than white?
The wind is coming up. We’d better head for shore. They finally arrived. I guess they will order soon. We shouldn’t leave yet. We just got here.
▲ 7. a. b.
8. a. b.
9. a. b.
▲ 10.
a. b.
1.
2.
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Good ties are made out of silk. That’s why they cost so much. Belts are like suspenders. They both keep your pants up. Rugby has lots of injuries because rugby players don’t wear pads.
Daphne owns an expensive car. She must be rich. This dog has fleas. I’ll bet it itches a lot. This dog has fleas. That explains why it scratches a lot.
Dennis’s salary is going up. He just got a promotion. Dennis’s salary went up after he got a promotion. Dennis’s salary won’t be going up; he didn’t get a promotion.
Outlawing adult websites may hamper free speech, but pornography must be curbed.
The grass must be mowed even though it is hot. The grass is getting long; time to mow.
Writing Exercises
Do people choose the sex they are attracted to? Write a one-page answer to this question, defending your answer with at least one supporting reason. Take about ten minutes to do this. Do not put your name on your essay. When everyone is finished, your instructor will collect the essays and redistribute them to the class. In groups of four or five, read the essays that have been given to your group. Divide the drafts into two batches, those that contain an argument and those that do not. Your instructor will ask each group to read to the class an essay that contains an argument and an essay that does not contain an argument (assuming that each group has at least one of each). The group should be prepared to explain why they feel each essay contains or fails to contain an argument. Is it ever okay to tell a lie? Take a position on this issue and write a short essay supporting it.
1. 2.
3. 4.
5. 6.
T
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Two Kinds of Reasoning
2
Students will learn to . . .
Recognize general features of arguments Distinguish between deductive and inductive arguments and evaluate them for validity, soundness, strength, and weakness Identify unstated premises Identify a balance of considerations argument and an inference to the best explanation (IBE) Distinguish between ethos, pathos, and logos as means of persuasion Use techniques for understanding and evaluating the structure and content of arguments
ime to look more closely at arguments—the kind that actually show something (unlike the red herrings and emotional appeals and other fallacies we are going to be talking about later).
ARGUMENTS: GENERAL FEATURES
To repeat, an argument consists of two parts. One part, the premise, is intended to provide a reason for accepting the second part, the conclusion. This statement is not an argument:
God exists.
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It’s just a statement. Likewise, this is not an argument:
God exists. That’s as plain as the nose on your face.
It’s just a slightly more emphatic statement. Nor is this an argument:
God exists, and if you don’t believe it, you will go to hell.
It just tries to scare us into believing God exists.
Also not an argument:
I think God exists, because I was raised a Baptist.
Yes, it looks a bit like an argument, but it isn’t. It merely explains why I believe in God.
On the other hand, this is an argument:
God exists because something had to cause the universe.
The difference between this and the earlier examples? This example has a premise (“something had to cause the universe”) and a conclusion (“God exists”).
As we explained in Chapter 1 (see page 8), an argument always has two parts: a premise part and a conclusion part. The premise part is intended to give a reason for accepting the conclusion part.
This probably seems fairly straightforward, but one or two complications are worth noting.
Conclusions Used as Premises
The same statement can be the conclusion of one argument and a premise in another argument:
Premise: The brakes aren’t working, the engine burns oil, the transmission needs work, and the car is hard to start. Conclusion 1: The car has outlived its usefulness.
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Conclusion 2: We should get a new car.
In this example, the statement “The car has outlived its usefulness” is the conclusion of one argument, and it is also a premise in the argument that we should get a new car.
Clearly, if a premise in an argument is uncertain or controversial or has been challenged, you might want to defend it—that is, argue that it is true. When you do, the premise becomes the conclusion of a new argument. However, every chain of reasoning must begin somewhere. If we ask a speaker to defend each premise with a further argument, and each premise in that argument with a further argument, and so on and so on, we eventually find ourselves being unreasonable, much like four-year- olds who keep asking “Why?” until they become exasperating. If we ask a speaker why he thinks the car has outlived its usefulness, he may mention that the car is hard to start. If we ask him why he thinks the car is hard to start, he probably won’t know what to say.
Unstated Premises and Conclusions
Another complication is that arguments can contain unstated premises. For example:
Premise: You can’t check out books from the library without an ID. Conclusion: Bill won’t be able to check out any books.
The unstated premise must be that Bill has no ID. An argument can even have an unstated conclusion. Here is an example:
Conclusion Indicators
When the words in the following list are used in arguments, they usually indicate that a premise has just been offered and that a conclusion is about to be presented. (The three dots represent the claim that is the conclusion.)
Thus . . . Consequently . . . Therefore . . . So . . . Hence . . . Accordingly . . . This shows that . . . This implies that . . . This suggests that . . . This proves that . . .
Example:
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Stacy drives a Porsche. This suggests that either she is rich or her parents are. The conclusion is
Either she is rich or her parents are. The premise is
Stacy drives a Porsche.
The political party that best reflects mainstream opinion will win the presidency in 2020 and the Republican Party best reflects mainstream opinion.
If a person said this, he or she would be implying that the Republican Party will win the presidency in 2020; that would be the unstated conclusion of the argument.
Unstated premises are common in real life because sometimes they seem too obvious to need mentioning. The argument “the car is beyond fixing, so we should get rid of it” actually has an unstated premise to the effect that we should get rid of any car that is beyond fixing; but this may seem so obvious to us that we don’t bother stating it.
Unstated conclusions also are not uncommon, though they are less common than unstated premises.
We’ll return to this subject in a moment.
TWO KINDS OF ARGUMENTS
Good arguments come in two varieties: deductive demonstrations and inductive supporting arguments.
Deductive Arguments
The premise (or premises) of a good deductive argument, if true, proves or demonstrates (these being the same thing for our purposes) its conclusion. However, there is more to this than meets the eye, and we must begin with the fundamental concept of deductive logic, validity. An argument is valid if it isn’t possible for the premise (or premises) to be true and the conclusion false. This may sound complicated, but it really isn’t. An example of a valid argument will help:
Premise Indicators
When the words in the following list are used in arguments, they generally introduce premises. They often occur just after a conclusion has been given. A premise would replace the three
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dots in an actual argument. Since . . . For . . . In view of . . . This is implied by . . .
Example: Either Stacy is rich or her parents are, since she drives a
Porsche. The premise is the claim that Stacy drives a Porsche; the conclusion is the claim that either Stacy is rich or her parents are.
Premises: Jimmy Carter was president immediately before Bill Clinton, and George W. Bush was president immediately after Bill Clinton. Conclusion: Jimmy Carter was president before George W. Bush.
As you can see, it’s impossible for these premises to be true and this conclusion to be false. So the argument is valid.
However, you may have noticed that the premises contain a mistake. Jimmy Carter was not president immediately before Bill Clinton. George H. W. Bush was president immediately before Bill Clinton. Nevertheless, even though a premise of the preceding argument is not true, the argument is still valid, because it isn’t possible for the premises to be true and the conclusion false. Another way to say this: If the premises were true, the conclusion could not be false—and that’s what “valid” means.
Now, when the premises of a valid argument are true, there is a word for it. In that case, the argument is said to be sound. Here is an example of a sound argument:
Premises: Bill Clinton is taller than George W. Bush, and Jimmy Carter is shorter than George W. Bush. Conclusion: Therefore, Bill Clinton is taller than Jimmy Carter.
This argument is sound because it is valid and the premises are true. As you can see, if an argument is sound, then its conclusion has been demonstrated.
Inductive Arguments
Again, the premise of a good deductive argument, if true, demonstrates that the conclusion is true. This brings us to the second kind of argument, the inductive
argument. The premise of a good inductive argument doesn’t demonstrate its conclusion; it supports it. For example:
After 2 P.M. the traffic slows to a crawl on the Bay Bridge. Therefore, it probably does the same thing on the Golden Gate Bridge.
The fact that traffic slows to a crawl after 2 P.M. on the Bay Bridge does not demonstrate or prove that it does that on the Golden Gate Bridge; it supports that conclusion. It makes it somewhat more likely that traffic on the Golden Gate Bridge slows to a crawl after 2 P.M.
Here is another example of an inductive argument:
Nobody has ever run a mile in less than three minutes. Therefore, nobody will ever run a mile in less than three minutes.
Like the first argument, the premise supports the conclusion but does not demonstrate or prove it.
If you are thinking that support is a matter of degree and that it can vary from just a little to a whole lot, you are right. Thus, inductive arguments are better or worse on a scale, depending on how much support their premises provide for the conclusion. Logicians have a technical word to describe this situation. The more support the premise of an inductive argument provides for the conclusion, the stronger the argument; the less support it provides, the weaker the argument. Put another way, one argument for a conclusion is weaker than another if it fails to raise the probability of the conclusion by as much. Thus, the first argument given above is weaker than the following argument:
After 2 P.M. the traffic slows to a crawl on the Bay Bridge, the San Mateo Bridge, the San Rafael Bridge, and the Dumbarton Bridge. Therefore, it probably does the same thing on the Golden Gate Bridge.
This argument is stronger than the first argument because its premise makes the conclusion more likely. The more bridges in a region on which traffic slows at a given time, the more likely it is that that phenomenon is universal on the bridges in the region.
One more example of an inductive argument:
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Alexandra rarely returns texts. Therefore, she probably rarely returns emails.
Once again, the premise supports but does not demonstrate or prove the conclusion. The differences between texting and emailing are sufficiently significant that the premise does not offer a great deal of support for the conclusion, but it does offer some. If Alexandra rarely returned telephone calls or letters as well as texts, that would make the argument stronger.
In Chapter 11 we will explain the criteria for evaluating inductive arguments.
BEYOND A REASONABLE DOUBT
In common law, the highest standard of proof is proof “beyond a reasonable doubt.” If you are a juror in a criminal trial, evidence will be presented to the court—facts that the interested parties consider relevant to the crime. Additionally, the prosecutor and counsel for the defense will offer arguments connecting the evidence to (or disconnecting it from) the guilt or innocence of the defendant. When the jury is asked to return a verdict, the judge will tell the jury that the defendant must be found not guilty unless the evidence proves guilt beyond a reasonable doubt.
Proof beyond a reasonable doubt actually is a lower standard than deductive demonstration. Deductive demonstration corresponds more to what, in ordinary English, might be expressed by the phrase “beyond any possible doubt.” Recall that in logic, a proposition has been demonstrated when it has been shown to be the conclusion of a sound argument—an argument in which (1) all premises are true and (2) it is impossible for the premises to be true and for the conclusion to be false. In this sense, many propositions people describe as having been demonstrated or proved, such as that smoking causes lung cancer or that the DNA found at a crime scene was the defendant’s, have not actually been proved in the logician’s sense of the word. So, in real life, when people say something has been demonstrated, they may well be speaking informally. They may not mean that something is the conclusion of a sound deductive argument. However, when we—the authors—say that something has been demonstrated, that is exactly what we mean.
TELLING THE DIFFERENCE BETWEEN DEDUCTIVE AND INDUCTIVE ARGUMENTS
A useful strategy for telling the difference between deductive and inductive arguments is to memorize a good example of each kind. Here are good examples of each:
Valid Deductive Argument: Juan lives on the equator. Therefore, Juan lives
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midway between the North and South poles.
Relatively Strong Inductive Argument: Juan lives on the equator. Therefore, Juan lives in a humid climate.
Study the two examples so that you understand the difference between them. In the left example, if you know the definition of “equator,” you already know it is midway between the poles. The right example is radically different. The definition of “equator” does not contain the information that it is humid. So:
If the conclusion of an argument is true by definition given the premise or premises, it is a valid deductive argument.
Often it is said that a valid deductive argument is valid due to its “form.” Thus, consider this argument:
If Juan is a fragglemop, then Juan is a snipette. Juan is not a snipette. Therefore, Juan is not a fragglemop.
What makes this argument valid is its form:
If P then Q. Not-Q. Therefore not-P.
You can see, however, that ultimately what makes the argument valid, and makes its form a valid form, is the way the words “If . . . then” and “not” work. If you know the way those words work, then you already know that the conclusion must be true given the two premises.
Another way of telling the difference between a deductive argument and an inductive argument is this: You generally would not say of a deductive argument that it supports or provides evidence for its conclusion. It would be odd to say that Juan’s living on the equator is evidence that he lives midway between the poles, or that it supports that claim. Thus:
If it sounds odd to speak of the argument as providing evidence or support for a
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contention, that’s an indication it is a deductive argument.
It would sound very odd to say, “The fact that Fido is a dog is evidence Fido is a mammal.” Fido’s being a dog isn’t evidence Fido is a mammal: it’s proof. “Fido is a dog; therefore Fido is a mammal” is a valid deductive argument.
DEDUCTION, INDUCTION, AND UNSTATED PREMISES
Somebody announces, “Rain is on its way.” Somebody else asks how he knows. He says, “There’s a south wind.” Is the speaker trying to demonstrate rain is coming? Probably not. His thinking, spelled out, is probably something like this:
Stated premise: The wind is from the south. Unstated premise: Around here, south winds are usually followed by rain. Conclusion: There will be rain.
In other words, the speaker was merely trying to show that rain was a good possibility. Notice, though, that the unstated premise in the argument could have been a
universal statement to the effect that a south wind always is followed by rain at this particular location, in which case the argument would be deductive:
Stated premise: The wind is from the south. Unstated premise: Around here, a south wind is always followed by rain. Conclusion: There will be rain.
Spelled out this way, the speaker’s thinking is deductive: It isn’t possible for the premises to be true and the conclusion to be false. So one might wonder abstractly what the speaker intended—an inductive argument that supports the belief that rain is coming, or a deductive demonstration.
There is, perhaps, no way to be certain short of asking the speaker something like, “Are you 100 percent positive?” But experience (“background knowledge”) tells us that wind from a particular direction is not a surefire indicator of rain. So probably the speaker did have in mind merely the first argument. He wasn’t trying to present a 100 percent certain, knock-down demonstration that it would rain; he was merely trying to establish there was a good chance of rain.
You can always turn an inductive argument with an unstated premise into a deductively valid argument by supplying the right universal premise—a statement that something holds without exception or is true everywhere or in all cases. Is that what the speaker really has in mind, though? You have to use background knowledge and
common sense to answer the question. For example, you overhear someone saying,
Stacy and Justin are on the brink of divorce. They’re always fighting.
One could turn this into a valid deductive argument by adding to it the universal statement “Every couple fighting is on the brink of divorce.” But such an unqualified universal statement seems unlikely. Probably the speaker wasn’t trying to demonstrate that Stacy and Justin are on the brink of divorce. He or she was merely trying to raise its likelihood. He or she was presenting evidence that Stacy and Justin are on the brink of divorce.
Often it is clear that the speaker does have a deductive argument in mind and has left some appropriate premise unstated. You overhear Professor Greene saying to Professor Brown,
“Flunk her! This is the second time you’ve caught her cheating.”
It would be strange to think that Professor Greene is merely trying to make it more likely that Professor Brown should flunk the student. Indeed, it is hard even to make sense of that suggestion. Professor Greene’s argument, spelled out, must be this:
Stated premise: This is the second time you’ve caught her cheating. Unstated premise: Anyone who has been caught cheating two times should be flunked. Conclusion: She should be flunked.
So context and content often make it clear what unstated premise a speaker has in mind and whether the argument is deductive or inductive.
Unfortunately, though, this isn’t always the case. We might hear someone say,
The bars are closed; therefore it is later than 2 A.M.
If the unstated premise in the speaker’s mind is something like “In this city, the bars all close at 2 A.M.,” then presumably he or she is thinking deductively and is evidently proffering proof that it’s after 2. But if the speaker’s unstated premise is something like “Most bars in this city close at 2 A.M.” or “Bars in this city usually close at 2 A.M.,” then we have an inductive argument that merely supports the conclusion. So which is the
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unstated premise? We really can’t say without knowing more about the situation or the speaker.
Is an Ad Photo an Argument?
The short answer: No. The longer version: Still no. An advertising photograph can “give you a reason” for buying something only in the sense that it can cause you to think of a reason. A photo is not an argument.
The bottom line is this. Real-life arguments often leave a premise unstated. One such unstated premise might make the argument inductive; another might make it deductive. Usually, context or content make reasonably clear what is intended; other times they may not. When they don’t, the best practice is to attribute to a speaker an unstated premise that at least is believable, everything considered. We’ll talk about believability in Chapter 4.
BALANCE OF CONSIDERATIONS
Should I get a dog? Miss class to attend my cousin’s wedding? Get chemo? Much everyday reasoning requires weighing considerations for and against thinking or doing something. Such reasoning, called balance of considerations reasoning, often contains both deductive and inductive elements. Here is an example:
Should assault weapons be banned? On the one hand, doing that would violate the Second Amendment to the U.S. Constitution. But on the other hand, when guns were outlawed in Australia the number of accidental gun deaths fell dramatically; that would probably happen here, too. It is a tough call.
The first consideration mentioned in this passage—that banning assault weapons
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would violate the Second Amendment and therefore should not be done—is a deductive argument. The second consideration mentioned—that banning assault weapons would reduce the number of accidental gun deaths—is an inductive argument.
Inductive arguments can be compared as to strength and weakness; deductive arguments can be compared as to validity and soundness. Assigning weight to considerations can be difficult, of course, but it is not hopelessly arbitrary. In Chapter 12 of this book, we discuss the perspectives within which moral evaluations are made; you will see there that weighing considerations of the sort presented in the example above depend to a certain extent on the moral perspective one adheres to.
INFERENCE TO THE BEST EXPLANATION (IBE)
An Inference to the Best Explanation (IBE) concludes that something exists or holds true or is a fact because that supposition best explains something we have observed or otherwise know. An example:
Neither the dog nor my husband is home, and the dog’s leash is gone. The best explanation of this is that my husband is out walking the dog. Therefore, my husband is out walking the dog.
Here is another example:
Sometimes my back really aches. Let’s see. Could it be due to gardening? Or lifting weights perhaps? No—it hurts all the time. Plus it seems to hurt more in the morning. And it started right after I bought that expensive mattress. Therefore, it’s the mattress that is hurting my back.
The conclusion of the argument is that the mattress is hurting my back; that supposition best explains the fact that my back hurts. Notice that the argument explicitly compares alternative explanations. It thus qualifies as a balance of considerations argument as well as an IBE, the “considerations” in this instance being alternative explanations.
Two more examples:
Sarah and another candidate were finalists for the teaching position. Sarah had better qualifications, but she had tattoos. The candidate who got the position didn’t have tattoos. Therefore, the fact she had tattoos caused Sarah to lose out on the position.
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There is water on the floor. Neither the bathtub nor the sink has been used and the ceiling isn’t leaking. The only source of water in the room is the toilet. Therefore, the toilet is leaking.
In the first example, the best explanation of Sarah’s not getting the position is thought to be the fact that she has tattoos. Since no other explanation was considered, you might say the tattoo explanation wins by default. In the second example, the leaking-toilet explanation was explicitly compared to other possible explanations and declared the winner.
Sometimes IBE is referred to as “abduction.” We treat it as a type of inductive reasoning, reasoning used to support rather than demonstrate a conclusion. In Chapter 11, we explore factors in terms of which one type of explanation might be said to be better than another.
WHAT ARE NOT PREMISES, CONCLUSIONS, OR ARGUMENTS
We hope you’ve noticed, when we use the word “argument,” we are not talking about two people having a feud or fuss about something. That use of the word has nothing much to do with critical thinking, though many a heated exchange could use some critical thinking. Arguments in our sense do not even need two people; we make arguments for our own use all the time. And when we evaluate them, we think critically.
Speaking of what arguments are not, it’s important to realize that not everything that might look like an argument, or like a premise or a conclusion, is one.
Pictures
Pictures are not premises, conclusions, or arguments. Neither are movies. Your iPhone can do lots of things, but it isn’t an argument. Sorry. Arguments have two parts, a premise part and a conclusion part, and both parts are propositional entities, which means (to repeat) that both parts must be expressible in declarative, true-or-false sentences. Movies and pictures can be moving, compelling, beautiful, complex, realistic, and so forth—but they cannot be either true or false. You can ask if what is depicted in a movie actually happened, or if the story upon which it is based is a true story, but you can’t really ask if a movie itself is true or false—or valid or invalid or relatively strong or weak. Such questions don’t make literal sense. If it doesn’t make sense to think of a thing as true or false, it cannot be a premise or a conclusion. If it doesn’t make sense to think of it as valid or invalid, or as being relatively strong or weak, it cannot be an argument.
The list of things that aren’t premises or conclusions or arguments therefore also includes emotions, feelings, landscapes, faces, gestures, grunts, groans, bribes, threats,
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amusement parks, and hip-hop. Since they may cause you to have an opinion or to form a judgment about something or produce an argument, you might be tempted to think of them as premises, but causes are not premises. A cause isn’t a propositional entity: it is neither true nor false. So it cannot be a premise.
If . . . then . . . Sentences
Sometimes sentences like the following are taken to state arguments:
If you wash your car now, then it will get spots.
This statement might be the premise of an argument whose conclusion is “Therefore you shouldn’t wash your car now.” It might also be the conclusion of an argument whose premise is “It is raining.” But though it could be a premise or a conclusion, it is not itself an argument. An argument has a premise and a conclusion, and, though the preceding statement has two parts, neither part by itself is either a premise or a conclusion. “If you wash your car now” is not a statement, and neither is “Then it will get spots.” Neither of these phrases qualifies as either a premise or a conclusion. Bottom line: “If . . . then . . .” sentences are not arguments.
Lists of Facts
Though the following might look like an argument, it is nothing more than a list of facts:
Identity theft is up at least tenfold over last year. More people have learned how easy it is to get hold of another’s Social Security number, bank account numbers, and such. The local police department reminds everyone to keep close watch on who has access to such information.
Although they are related by being about the same subject, none of these claims is offered as a reason for believing another, and thus there is no argument here. But the following passage is different. See if you can spot why it makes an argument:
The number of people who have learned how to steal identities has doubled in the past year. So you are now more likely to become a victim of identity theft than you were a year ago.
Here, the first claim offers a reason for accepting the second claim; we now have
an argument.
“A because B”
Sometimes the word “because” refers to the cause of something. But other times it refers to a premise of an argument. Mike walks into the motel lobby, wearing a swimsuit and dripping wet. Consider these two statements:
“Mike is in his swimsuit because he was swimming.”
“Mike was swimming because he’s in his swimsuit.”
These two sentences have the same form, “X because Y.” But the sentence on the left explains why Mike is wearing a swimsuit. The sentence on the right offers an argument that Mike was swimming. Only the sentence on the right is an argument. Put it this way: What follows “because” in the sentence on the left is the cause. What follows “because” in the right-hand sentence is evidence.
Be sure you understand the difference between these two sentences. Arguments and cause-and-effect statements can both employ the phrase “X because Y.” But there the similarity ends. When what follows “because” is a reason for accepting a contention, or evidence for it, we have an argument; when what follows “because” states the cause of something, we have a cause-and-effect explanation. These are entirely different enterprises. Arguing that a dog has fleas is different from explaining what gave it fleas. Arguing that violent crime has increased is different from explaining what caused it to increase.
ETHOS, PATHOS, AND LOGOS
When he was a young man, Alexander the Great conquered the world. Alexander was enormously proud of his accomplishment, and named several cities after himself. Alexander’s teacher, the Greek philosopher Aristotle, had no cities named after him (there is no indication that this disappointed Aristotle). Nevertheless, Aristotle’s imprint on civilization turned out to be even more profound than Alexander’s.
Page 44Aristotle, who now is regarded as the father of logic, biology, and psychology, made enduring contributions to virtually every subject. These include (in addition to those just mentioned) physics, astronomy, meteorology, zoology, metaphysics, political science, economics, ethics, and rhetoric.
Among Aristotle’s contributions in the last field (rhetoric) was a theory of persuasion, which famously contained the idea that there are three modes by which a speaker may persuade an audience. Paraphrasing very loosely, Aristotle’s idea was that we can be persuaded, first of all, by a speaker’s personal attributes, including such things as his or her background, reputation, accomplishments, expertise, and similar things. Aristotle referred to this mode of persuasion as ethos. Second, a speaker can persuade us by connecting with us on a personal level, and by arousing and appealing to our emotions by a skillful use of rhetoric. This mode of persuasion Aristotle termed pathos. And third, the speaker may persuade us by using information and arguments— what he called logos.
■ First known pic of Aristotle taking a selfie.
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Unfortunately, logos—rational argumentation—is one of the least effective ways of winning someone to your point of view. That’s why advertisers rarely bother with it. When the sellers of the first home automatic breadmaker found that its new kitchen device didn’t interest people, they advertised the availability of a second model of the same machine, which was only slightly larger but much more expensive. When consumers saw that the first model was a great buy, they suddenly discovered they wanted one, and began snapping it up. Why try to persuade people by rational argument that they need a breadmaker when you can get them to think they do simply by making them believe they have sniffed out a bargain?*
Still, despite the general inefficacy of logos as a tool of persuasion, people do frequently use arguments when they try to persuade others. This might lead you to define an argument as an attempt to persuade. But that won’t do. Remember, there are two kinds of argument. Deductive arguments are either sound or unsound, and whether a deductive argument is one or the other doesn’t depend in the least on whether anyone is persuaded by it. Likewise, inductive arguments are in varying degrees strong or weak; their strength depends on the degree to which their premises elevate the probability of the conclusion, and that, too, is independent of whether anyone finds them persuasive. The very same argument might be persuasive to Parker but not to Moore, which shows that the persuasiveness of an argument is a subjective question of psychology, not of logic. Indeed, the individual who does not think critically is precisely the person who is persuaded by specious reasoning. People notoriously are unfazed by good arguments while finding even the worst arguments compelling. If you want to persuade people of something, try propaganda. Flattery has been known to work, too.
We will be looking at alternative modes of persuasion—what Aristotle called ethos and pathos—in considerable detail in Chapters 4, 5, 6, 7, and 8. However, we do this not so you can persuade people, but so you can be alert to the influence of ethos and pathos on your own thinking.
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