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Critical Reasoning
Consider the terms vague, ambiguity and generality as they relate to our textbook reading for this week.
How are vagueness, ambiguity and generality used in politics or in law in order to achieve a desired outcome?
What are some examples of how this might be applied in your future career?
Include an example or two from current events that demonstrates the use of vagueness, ambiguity and generality.
Feel free to share an article, a screenshot of a social media post, a video, etc
Please use the textbook as reference and also cite the reference at the end
Page i
Twelfth Edition
Critical Thinking
Brooke Noel Moore Richard Parker California State University, Chico
with help in Chapter 12 from Nina Rosenstand and Anita Silvers
Page ii
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.
This book is printed on acid-free paper.
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ISBN 978-1-259-69087-7 MHID 1-259-69087-3
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All credits appearing on page or at the end of the book are considered to be an extension of the copyright page.
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.
mheducation.com/highered
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
Page v
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
Page vi
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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Page viii
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
Page ix
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
Page x
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
Page xii
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.
Page xx
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
Page xxi
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
Page xxii
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.
Page xxiii
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
Page xxvi
This is not entirely a work of nonfiction.
1. 2. 3. 4. 5.
6.
A
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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.
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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.
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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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▲ 1.
2.
3.
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?
▲ 4.
5.
a. b. c. d. ■ ■ ■ ■ ■ ■ ■ ■
■ ■
■
■
■
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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.
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