connect and won't be retained. I've introduced the fallacies along with the good
arguments they mock (for example, slippery slope with reasoning in a chain with
conditionals, mistaking the person for the claim with a discussion of when it's
appropriate to accept an unsupported claim), so that Chapter 11 is a summary and
PREFACE to the Instructor
overview. Covering this material here helps students unify the earlier material and
gives them some breathing room after the work in Chapters 6 and 8.
It's only at the end of this section, working through Short Arguments for
Analysis, that students will begin to feel comfortable with the ideas from the earliest
chapters. You can conclude a course for the quarter system here. Then Complex
Arguments for Analysis introduces more about the structure of arguments and how
to analyze longer, more difficult examples, with twenty-one long arguments as
exercises.
The last part, Reasoning About Our Experience (Chapters 12-15), covers
specific kinds of arguments: analogies, generalizations, and cause and effect.
Chapter 13 on numerical claims could follow directly after Chapter 5.
The accompanying Workbook for Critical Thinking contains every exercise
from the text in a format that makes students do the basic steps in argument analysis
for each argument they encounter. Checking the work is much easier from the
uniform answer sheets. The Workbook contains additional material, including
Exercises and Examples from the Law. There is an alternative Science Workbook
for the text that contains exercises on applying critical thinking to the sciences, with
additional material on observations and experiments, models, and explanations. The
Instructor's Manual CD has suggestions and a syllabus for the Science Workbook.
Writing Lessons are an integral part of the course. Included are two types of
writing exercises. The Essay Writing Lessons require the student to write an
argument for or against a given issue, where the issue and the method of argument
are tied to the material that's just been presented. About midway through the course
your students can read the section "Composing Good Arguments," which
summarizes the lessons they should learn. In the Instructor's Manual there are
suggestions for making the grading of these relatively easy.
The Cartoon Writing Lessons present a situation or a series of actions in a
cartoon, and require the student to write the best argument possible for a claim based
on that. These lessons do more to teach students reasoning than any other type of
exercise. Students have to distinguish between observation and inference; they have
to judge whether a good argument is possible; they have to judge whether the claim
is objective or subjective; they have to judge whether a strong argument or a valid
argument is called for. These deserve class time for discussion.
Together, these exercises and a few others from the chapters provide more
than enough assignments for courses that require a substantial writing component.
Special features of this text
• The material is tied into a single whole, a one-semester course covering the basics.
The text is meant to be read and studied from one end to the other.
As an example of how the ideas fit together as one piece, the Principle of
Rational Discussion and the Guide to Repairing Arguments (Chapter 4) play a
PREFACE to the Instructor
central role in any argument analysis and are used continuously to give shape to the
analyses. They serve to organize the fallacies (Chapter 11), so that fallacies are not
just a confusing list.
• There are more than a thousand exercises and hundreds of examples taken from
daily life. Dialogues among cartoon characters sound like the reasoning students
encounter every day. Examples from newspapers and other media are focused on the
ideas in the text and on what will interest students. Philosophical issues are raised in
the context of dialogues that students can imagine hearing their friends say. The text
relates theory to the needs of students to reason in their own lives.
In each section the exercises move from stating a definition, to relating the
various ideas, to applying the concepts. The most important ideas are reinforced
with similar exercises in succeeding sections. Worked examples in the text help
students see how to begin with their homework.
• Cartoons have been drawn especially for this book to reinforce the ideas, to show
relationships of ideas, and to get students to convert nonverbal experience into
arguments. The Cartoon Writing Lessons help students grasp the ideas much faster.
• Examples and Exercises from the Law are given in the Workbook. For example,
Montana's Supreme Court ruling regarding the basic law on speeding is presented in
the discussion of vagueness; a Federal Trade Commission decision on truth in
advertising is linked to the discussion of when to accept an unsupported claim.
• There is a complete Instructor's Manual with suggestions for teaching and answers
to the exercises in the text. An accompanying Instructor's CD contains fifty-four
sample exams, answers to those, more than five hundred additional examples, and
additional material ready to modify and print.
• Five Ways of Saying "Therefore" also available from Wadsworth, was written to
provide a theoretical framework for the ideas presented in this text. It is also suitable
for an upper-division course.
• Definitions and key ideas are boxed. It's easy to find the important material.
• The text is fun to read, yet challenges the very best student.
New to the Third Edition
• Carolyn Kernberger, my co-author for The Guide to Critical Thinking in
Economics, has collaborated in rewriting the material to make it easier to teach.
• A new section on prescriptive and descriptive claims has been added to Chapter 2.
That distinction is followed through in analyses of many examples in the text. It is
particularly useful in the discussion of appeals to emotions.
• A new section on graphs has been added to the chapter on numerical claims.
PREFACE to the Instructor
• A new section on advertising and the Internet has been added to the chapter on
evaluating unsupported claims.
• There are 198 new exercises and 62 new examples.
I've tried to steer between the Scylla of saying nonsense
and the Charybdis of teaching only trivialities. I hope
you find the journey memorable. The water is deep.
Acknowledgments
I am grateful that so many people have been willing to give their time and ideas to
help me improve this text. I am indebted to:
• Tom Bittner, Jeanette Catsoulis, Vanessa Christopher, Peter Eggenberger,
Stephen Epstein, Maurice Finocchiaro, Peter Hadreas, Neta Hoff, Todd Jones,
Susan Kowalski, Fred Kroon, Ron Leonard, Benson Mates, and Maria Sanders for
discussions on the ideas and drafts of the first edition.
• Reviewers, whose comments were crucial in clearing up confusions and shaping
the text. First edition David Adams, Phyllis Berger, Blanche Radford Curry,
Betsy Decyk, Roger Ebertz, George Gale, Kevin Galvin, James W. Garson, Don
Levi, Isabel Lue
ngo, Brian J. Rosmaita, Darlene Macomber, and Kenneth Stern.
Second edition and the Science Workbook Sharon Crasnow, Brian Domino, Gary
Elkins, James F. Sennett, William Tinsley, James F. Sennett, and Gina Zavota.
Third edition Theodore Gracyk, Carol J. Nicholson, G. A. Spangler, Scot Miller,
and Jim Chesher.
• Peter Adams for many good suggestions on how to organize and present the
material, and for his help and encouragement throughout.
• Alex Raffi who contributed so many ideas in collaboration on the cartoons.
• My development editors, whose suggestions improved the text. First edition
Alan Venable; Second edition Kara Kindstrom; Third edition Lee McCracken.
• Stephen Epstein, Paul Yackel, and Adriana Zuiiiga for working through and
correcting a draft of the Science Workbook.
• Elizabeth Ray and Mark McNellis for some excellent examples.
• Robert Epstein and Christian Fritz for help on the examples from the law.
• Mircea Dumitru and William S. Robinson for comments on the appendix on
Aristotelian logic.
• Signe Wolsgard Kr0yer and Rasmus Ploug for reading through the entire draft of
the third edition and making many helpful comments.
• Timothy A. D. Hyde for suggestions and critiques for the third edition.
• And my students, who provided me with many examples, whose quizzical looks
made me rewrite, and whose delight in the material motivated me to finish this
book.
I am grateful to them all. Much of what is good in this text
comes from them. What is bad is mine, all mine.
Excerpts on the following pages are reprinted by permission of the following persons or organizations.
pages 10, 183, 189, 190, 203-205, 214, 226, 234, 240-241, The Spectrum.
page 15, Heather Subran.
page 15, Knoxville News-Sentinel
pages 19, 76, 91, 92, 187, 188, 189, 190, 220, 239, 268-269, 277, 296, 298-299, 324-325,
327-328, Associated Press.
pages 28-29, 230, 248-250, Las Vegas Review-Journal.
pages 65, 235-237, 245, 263, El Defensor Chieftain.
pages 76, 188-189, 216, 237-238, 245-247, 269-270, 276, Albuquerque Tribune.
Permission does not imply endorsement,
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Reprinted with permission.
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pages 188, 263-264, Albuquerque Journal. Permission does not imply endorsement,
page 215, courtesy CNN. Usage of this material does not constitute an implied or expressed
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pages 226-227, 233, 238-239, Scripps Howard News Service, United Media,
pages 239-240, Dr. William Hamilton,
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page 277, Apartment Association of New Mexico,
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pages 296-298, New England Journal of Medicine, © 1990, Massachusetts Medical Society.
All rights reserved,
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page 325, Affirmative Parenting.
pages 328-329, University of California Press. ©1988, The Regents of the University of
California,
pages 331-332, Dollars & Sense.
pages 333-336, Las Vegas Sun.
The FUNDAMENTALS
1 Critical Thinking?
A. Are You Convinced? 1
B. Claims 2
C. Arguments 4
Summary 7
• Exercises for Chapter 1 7
A. Are You Convinced?
Everyone's trying to convince you of something: You should go to bed early. You
should drop out of college. You should buy a Dodge Ram truck. You should study
critical thinking . . . . And you spend a lot of time trying to decide what you should
be doing, that is, trying to convince yourself: Should I take out a student loan? Is
chocolate bad for my complexion? Should I really date someone who owns a cat?
Are you tired of being conned? Of falling for every pitch? Of making bad
decisions? Of fooling yourself? Or just being confused?
Thinking critically is a defense against a world of too much information and
too many people trying to convince us. But it is more. Reasoning is what
distinguishes us from beasts. Many of them can see better, can hear better, and
are stronger. But they cannot plan, they cannot think through, they cannot discuss
in the hopes of understanding better.
An older student was in the spring term of his senior year when he took this
course. He was majoring in anthropology and planned to do graduate work in the
fall. Late in the term he brought me a fifteen-page paper he'd written for an
anthropology class. He said he'd completed it, then he went over it again, analyzing
it as we would in class, after each paragraph asking, "So?" He found that he couldn't
justify his conclusion, so he changed it and cut the paper down to eleven pages. He
showed me the professor's comments, which were roughly "Beautifully reasoned,
clear. A+." He said it was the first A+he'd ever gotten. I can't promise that you'll
get an A on all your term papers after taking this course. But you'll be able to
comprehend better what you're reading and write more clearly and convincingly.
1
2 CHAPTER 1 Critical Thinking?
Once in a while I'll tune into a sports talk show on the radio. All kinds of
and well reasoned. The callers know the details, the facts, and make serious
projections about what might be the best strategy based on past experience. They
comment on what caused a team to win or lose; they reason with great skill and
reject bad arguments. I expect that you can too, at least on subjects you consider
important. What we hope to do in this course is hone that skill, sharpen your
judgment, and show you that the methods of evaluating reasoning apply to much
in your life.
In trying to understand how to reason well, we'll also study bad ways to
convince, ways we wish to avoid, ways that misuse emotions or rely on deception.
You could use that knowledge to become a bad trial lawyer, but I hope you will learn
a love of reasoning well, for it is not just ethical to reason well; it is, as we shall see,
more effective in the long run. Critical thinking is part of the study of philosophy:
the love of wisdom. We might not reach the truth, but we can be searchers, lovers of
wisdom, and treat others as if they are, too.
B. Claims
We'll be studying the process of convincing. An attempt to convince depends on
someone trying to do the convincing and someone who is supposed to be convinced.
• Someone tries to convince you.
• You try to convince someone else.
• You try to convince yourself.
Let's call an attempt to convince an "argument."
But, you say, an argument means someone yelling at someone else. When my
mom yells at me and I yell back, that's an argument. Yes, perhaps it is. But so, by
our definition, is you and your friend sitting down to talk about your college finances
to decide wh
ether you need to get a job. We need a term that will cover our attempts
to convince. The word "argument" has become pretty standard.
SECTION B Claims 3
Still, that isn't right. Suppose the school bully comes up to Flo and says, "Hand
over your candy bar." Flo won't. She hits Flo on the head with a stick. Flo gives up
her candy bar. Flo's been convinced. But that's no argument.
The kind of attempts to convince we'll be studying here are ones that are or can
be put into language. That is, they are a bunch of sentences that we can think about.
But what kind of sentences?
When we say an argument is an attempt to convince, what exactly is it we're
supposed to be convinced of? To do something? If we are to try to reason using
arguments, the point is that something is true. And what is that something?
A sentence, for it's sentences that are true or false. And only certain kinds of
sentences: not threats, not commands, not questions, not prayers. An attempt to
convince, in order to be classified as an argument, should be couched in plain
language that is true or false: declarative sentences.
You should already know what a declarative sentence is. For example:
This course is a delight.
The author of this book sure writes well.
Intelligent beings once lived on Mars.
Everyone should brush his or her teeth at least once every day.
Nobody knows the troubles I've seen.
The following are not declarative sentences:
Shut that door!
How often do I have to tell you to wipe your feet before you come into
the house?
Dear God, let me be a millionaire instead of a starving student.
Still, not every declarative sentence is true or false: "Green dreams ride
donkeys" is a declarative sentence, but it's nonsense. Let's give a name to those
sentences that are true or false, that is, that have a truth-value.
Claim A declarative sentence used in such a way that it is either true or false
(but not both).
One of the most important steps in trying to understand new ideas or new ways
of talking is to look at lots of examples.
E x a m p l e s Are the following claims?
Example 1 Your instructor for this course is male.
Analysis This is a claim. It's either true or false.