A Guide to Critical Thinking

With Good Reason: A Guide to Critical Thinking

Christopher Foster Ashford University

James Hardy Ashford University

Gloria Zúñiga y Postigo Ashford University

har85668_00_fm_i-xviii.indd 1 4/9/15 1:42 PM

James Hardy, Christopher Foster, and Gloria Zúñiga y Postigo

With Good Reason: A Guide to Critical Thinking

Editor in Chief, AVP: Steve Wainwright

Executive Editor: Anna Lustig

Development Editor: Rebecca Paynter

Assistant Editor: Jessica Sarra

Editorial Assistant: Lukas Schulze

Production Editor: Catherine Morris

Media Production: Amanda Nixon, LSF Editorial

Copy Editor: Lauri Scherer, LSF Editorial

Photo Researcher: Amanda Nixon, LSF Editorial

Cover Design: Bambang Suparman Ibrahim

Printing Services: Bordeaux

Production Services: Lachina

Permission Editor: D’Stair Permissions Agency

Cover Image: juuce/iStock and espiegle/iStock

ISBN-10: 1621785661

ISBN-13: 978-1-62178-566-8

Copyright © 2015 Bridgepoint Education, Inc.

All rights reserved.

GRANT OF PERMISSION TO PRINT: The copyright owner of this material hereby grants the holder of this

publication the right to print these materials for personal use. The holder of this material may print the materials

herein for personal use only. Any print, reprint, reproduction or distribution of these materials for commercial use

without the express written consent of the copyright owner constitutes a violation of the U.S. Copyright Act,

17 U.S.C. §§ 101-810, as amended.

har85668_00_fm_i-xviii.indd 2 4/9/15 1:42 PM

Brief Contents

Chapter 1: An Introduction to Critical Thinking and Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Chapter 2: The Argument . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25

Chapter 3: Deductive Reasoning . . . . . . . . . . . . . . . . . . . . . . . . .59

Chapter 4: Propositional Logic . . . . . . . . . . . . . . . . . . . . . . . . 119

Chapter 5: Inductive Reasoning . . . . . . . . . . . . . . . . . . . . . . . 165

Chapter 6: Deduction and Induction: Putting It All Together . . . . . . . . . . . . . . . . . . . . . . 207

Chapter 7: Informal Fallacies . . . . . . . . . . . . . . . . . . . . . . . . . . 239

Chapter 8: Persuasion and Rhetoric . . . . . . . . . . . . . . . . . . . 279

Chapter 9: Logic in Real Life . . . . . . . . . . . . . . . . . . . . . . . . . . . 319

Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 355

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363

har85668_00_fm_i-xviii.indd 3 4/9/15 1:42 PM

About the Authors xiii Acknowledgments xv Preface xvii

Chapter 1 An Introduction to Critical Thinking and Logic 1

1 .1 What Is Critical Thinking? 2 The Importance of Critical Thinking 3 Becoming a Critical Thinker 6

1 .2 Three Misconceptions About Logic 7 Logic Is for Robots 7 Logic Does Not Need to Be Learned 9 Logic Is Too Hard 10

1 .3 What Is Logic? 11 The Study of Arguments 11 A Tool for Arriving at Warranted Judgments 12 Formal Versus Informal Logic 14

1 .4 Arguments Outside of Logic 14 Arguments in Ordinary Language 14 Rhetorical Arguments 15 Revisiting Arguments in Logic 16

1 .5 The Importance of Language in Logic 17

1 .6 Logic and Philosophy 19 The Goal of Philosophy 20 Philosophy and Logical Reasoning 20

Summary and Resources 21


har85668_00_fm_i-xviii.indd 5 4/9/15 1:42 PM

Chapter 2 The Argument 25

2 .1 Arguments in Logic 26 Claims 29 The Standard Argument Form 31

2 .2 Putting Arguments in the Standard Form 33 Find the Conclusion First 34 Find the Premises Next 36 The Necessity of Paraphrasing 38 Thinking Analytically 39

2 .3 Representing Arguments Graphically 42 Representing Reasons That Support a Conclusion 42 Representing Counterarguments 45 Diagramming Efficiently 46

2 .4 Classifying Arguments 47 Deductive Arguments 48 Inductive Arguments 49 Arguments Versus Explanations 50

Summary and Resources 53

Chapter 3 Deductive Reasoning 59

3 .1 Basic Concepts in Deductive Reasoning 60 Validity 60 Soundness 62 Deduction 63

3 .2 Evaluating Deductive Arguments 66 Representing Logical Form 66 Using the Counterexample Method 68

3 .3 Types of Deductive Arguments 70 Mathematical Arguments 70 Arguments From Definitions 71 Categorical Arguments 72 Propositional Arguments 72

3 .4 Categorical Logic: Introducing Categorical Statements 73 Clarifying Particular Statements 76


har85668_00_fm_i-xviii.indd 6 4/9/15 1:42 PM


Clarifying Universal Statements 76 Accounting for Conversational Implication 78

3 .5 Categorical Logic: Venn Diagrams as Pictures of Meaning 80 Drawing Venn Diagrams 81 Drawing Immediate Inferences 84

3 .6 Categorical Logic: Categorical Syllogisms 91 Terms 91 Distribution 91 Rules for Validity 93 Venn Diagram Tests for Validity 94

3 .7 Categorical Logic: Types of Categorical Arguments 111 Sorites 111 Enthymemes 112 Validity in Complex Arguments 113

Summary and Resources 115

Chapter 4 Propositional Logic 119

4 .1 Basic Concepts in Propositional Logic 120 The Value of Formal Logic 121 Statement Forms 122

4 .2 Logical Operators 123 Conjunction 124 Disjunction 126 Negation 128 Conditional 129

4 .3 Symbolizing Complex Statements 133 Truth Tables With Complex Statements 135 Truth Tables With Three Letters 137

4 .4 Using Truth Tables to Test for Validity 140 Examples With Arguments With Two Letters 141 Examples With Arguments With Three Letters 144

4 .5 Some Famous Propositional Argument Forms 149 Common Valid Forms 149 Common Invalid Forms 152

Summary and Resources 158

har85668_00_fm_i-xviii.indd 7 4/9/15 1:42 PM


Chapter 5 Inductive Reasoning 165

5 .1 Basic Concepts in Inductive Reasoning 166 Inductive Strength 167 Inductive Cogency 170

5 .2 Statistical Arguments: Statistical Syllogisms 171 Form 172 Weak Statistical Syllogisms 173

5 .3 Statistical Arguments: Inductive Generalizations 174 Representativeness 175 Confidence Level 179 Applying This Knowledge 180

5 .4 Causal Relationships: The Meaning of Cause 181 Sufficient Conditions 181 Necessary Conditions 182 Necessary and Sufficient Conditions 183 Other Types of Causes 184 Correlational Relationships 184

5 .5 Causal Arguments: Mill’s Methods 186 Method of Agreement 187 Method of Difference 188 Joint Method of Agreement and Difference 189 Method of Concomitant Variation 190

5 .6 Arguments From Authority 192

5 .7 Arguments From Analogy 193 Evaluating Arguments From Analogy 194 Analogies in Moral Reasoning 197 Other Uses of Analogies 198

Summary and Resources 203

Chapter 6 Deduction and Induction: Putting It All Together 207

6 .1 Contrasting Deduction and Induction 208

har85668_00_fm_i-xviii.indd 8 4/9/15 1:42 PM


6 .2 Choosing Between Induction and Deduction 211 Availability 211 Robustness 212 Persuasiveness 214

6 .3 Combining Induction and Deduction 216

6 .4 Reasoning About Science: The Hypothetico–Deductive Method 218 Step 1: Formulate a Hypothesis 219 Step 2: Deduce a Consequence From the Hypothesis 219 Step 3: Test Whether the Consequence Occurs 220 Step 4: Reject the Hypothesis If the Consequence Does Not Occur 220

6 .5 Inference to the Best Explanation 225 Form 228 Virtue of Simplicity 229 How to Assess an Explanation 231 A Limitation 232

Summary and Resources 236

Chapter 7 Informal Fallacies 239

7 .1 Fallacies of Support 241 Begging the Question 241 Circular Reasoning 242 Hasty Generalizations and Biased Samples 243 Appeal to Ignorance and Shifting the Burden of Proof 245 Appeal to Inadequate Authority 246 False Dilemma 248 False Cause 249

7 .2 Fallacies of Relevance 251 Red Herring and Non Sequitur 251 Appeal to Emotion 252 Appeal to Popular Opinion 255 Appeal to Tradition 256 Ad Hominem and Poisoning the Well 257

7 .3 Fallacies of Clarity 261 The Slippery Slope 261 Equivocations 262 The Straw Man 264

har85668_00_fm_i-xviii.indd 9 4/9/15 1:42 PM


Fallacy of Accident 267 Fallacies of Composition and Division 268

Summary and Resources 273

Chapter 8 Persuasion and Rhetoric 279

8 .1 Obstacles to Critical Thinking: The Self 280 Stereotypes 280 Cognitive Biases 282

8 .2 Obstacles to Critical Thinking: Rhetorical Devices 289 Weasel Words 290 Euphemisms and Dysphemisms 291 Proof Surrogates 293 Hyperbole 294 Innuendo and Paralipsis 295

8 .3 The Media and Mediated Information 300 Manipulating Images 301 Advertising 302 Other Types of Mediated Information 306

8 .4 Evaluating the Source: Who to Believe 308 Reputation and Authorship 309 Accuracy and Currency 312 Interested Parties 312

Summary and Resources 314

Chapter 9 Logic in Real Life 319

9 .1 The Argumentative Essay 320 The Problem 321 The Thesis 322 The Premises 323

9 .2 Strengthening the Argumentative Essay 327 Clarification and Support 327 The Objection 329 The Rebuttal 330 Closing Your Essay 331

har85668_00_fm_i-xviii.indd 10 4/9/15 1:42 PM


9 .3 Practical Arguments: Building Arguments for Everyday Use 333 The Claim 333 The Data 334 The Warrant 334 Comparing the Models 335

9 .4 Confronting Disagreement 338 Applying the Principle of Accuracy 339 Applying the Principle of Charity 340 Balancing the Principles of Accuracy and Charity 341 Practicing Effective Criticism 342

9 .5 Case Study: Interpretation and Criticism in Practice 346 Examining the Initial Argument 347 Examining the Objection 347 Examining the Wording 348 Drawing a Conclusion 349

9 .6 Other Applications of Logic 349 Symbolic Logic 350 Computer Science 350 Artificial Intelligence 350 Engineering 351 Politics (Speech Writing) 351

Summary and Resources 351

Glossary 355

References 363

har85668_00_fm_i-xviii.indd 11 4/9/15 1:42 PM

James Hardy, Ashford University Dr. James Hardy is part of the core faculty of the Humanities & Science department at Ashford University. He obtained a PhD in philosophy from Indiana University, a master’s degree in philosophy from the University of Washington, and bachelor’s degrees in philosophy and psy- chology from Utah State University. He has taught philosophy at multiple universities since 1998 and has had the opportunity to teach across the general education spectrum, including courses in algebra, speech, English, and physics. Dr. Hardy’s favorite part of teaching is watch- ing students get excited about learning, helping them achieve their dreams, and seeing their excitement as new worlds of knowledge open up to them.

Dr. Hardy loves spending time outdoors hiking, backpacking, and canoeing—especially when he can do so with family members. He has lived all over the United States and has always found beauty and natural wonders wherever he has lived. The only time he is happier than when he is in nature is when he is spending time with his family.

Christopher Foster, Ashford University Dr. Christopher Foster is lead faculty of the Humanities & Science department at Ashford University. He holds a PhD in philosophy with a specialization in logic and language and a master’s degree in philosophy from the University of Kansas (KU). His undergraduate work was completed at the University of California–Davis, where he earned bachelor’s degrees in mathematics and philosophy. Dr. Foster began his career as a graduate teaching assistant at KU and went on to teach at Brigham Young University and Utah Valley University. Dr. Foster has a passion for philosophy and believes that digging deeply into life’s ultimate questions is often the best way to improve students’ critical thinking and writing skills. He lives in Orem, Utah, with his wife, Cherie, and two daughters, Avery and Adia.

Gloria Zúñiga y Postigo, Ashford University Dr. Gloria Zúñiga y Postigo is part of the core faculty of the Humanities & Science department at Ashford University. She earned a PhD in philosophy from the University at Buffalo, special- izing in ontology, ethics, and philosophy of economics. Her previous studies are in philosophy at the University of California–Berkeley and economics at California State University–East Bay. Dr. Zúñiga y Postigo’s present research interests include examinations of the effect in our experiences of moral, aesthetic, and economic phenomena; and value in the Brentano School, the Menger School, and the Göttingen Circle scholars. Teaching philosophy is one her greatest passions. She especially enjoys teaching informal logic, because it empowers students with a tool for distinguishing truth from the mere appearance of truth, thereby making it possible for them to achieve fulfilling lives with greater efficacy.

About the Authors

har85668_00_fm_i-xviii.indd 13 4/9/15 1:42 PM

The authors would like to acknowledge the people who made significant contributions to the development of this text: Anna Lustig, executive editor; Rebecca Paynter, development edi- tor; Jessica Sarra, assistant editor; Lukas Schulze, editorial assistant; Catherine Morris, pro- duction editor; Amanda Nixon, media production; and Lauri Scherer and LSF Editorial, copy editors. Additional thanks go to Justin Harrison and Marc Joseph for their work creating and accuracy checking the ancillary materials for this text.

The authors would also like to thank the following reviewers, as well as other anonymous reviewers, for their valuable feedback and insight:

Justin Harrison, Ashford University

Mark Hébert, Austin College

Marc Joseph, Mills College

Stephen Krogh, Ashford University

Renee Levant, Ashford University

Andrew Magrath, Kent State University

Zachary Martin, Florida State University

John McAteer, Ashford University

Bradley Thames, Ashford University

Finally, but not least importantly, the authors would like to acknowledge their respective spouses—Teresa Hardy, Cherie Farnes, and Jacob Arfwedson—for their loving understand- ing of the long hours that this project demanded, as well as all characters in popular culture (for example, Sherlock Holmes, Mr. Spock, and Dr. House) who have kept logic present in everyday conversations. The rewards of our work are enriched by the former and reassured by the latter.


har85668_00_fm_i-xviii.indd 15 4/9/15 1:42 PM

With Good Reason: A Guide to Critical Thinking examines the specific ways we use language to reason about things. The study of logic improves our ability to think. It forces us to pay closer attention to the way language is used (and misused). It helps make us better at providing good reasons for our decisions. With Good Reason: A Guide to Critical Thinking seeks to help you examine and develop these abilities in order to improve them and to avoid being per- suaded by the faulty reasoning of others.

Textbook Features With Good Reason: A Guide to Critical Thinking includes a number of features to help students understand key concepts and think critically:

Everyday Logic boxes give students the opportunity to see principles applied to a variety of real-world scenarios.

A Closer Look boxes give students the chance to explore more in-depth concepts and issues in critical thinking.

Figures illustrate a variety of concepts in easy-to-understand ways.

Practice Problems provide an opportunity for students to exercise the knowledge they have learned in each chapter.

Knowledge Checks test preconceptions about and comprehension of each chapter’s top- ics and lead to a personalized reading plan based on these results.

Moral of the Story boxes and Chapter Summaries review the key ideas and takeaways in each chapter.

Interactive Features in the e-book allow students to engage with the content on a more dynamic level. Animated scenarios in Logic in Action show students how logic might be used in real life. Consider This interactions invite students to think about various issues in more depth. Interactive exercises in Connecting the Dots give students further opportuni- ties to practice what they have learned.

Key Terms list and define important vocabulary discussed in the chapter, offering an opportunity for a final review of chapter concepts. In the e-book, students can click on the term to reveal the definition and quiz themselves in the process.


har85668_00_fm_i-xviii.indd 17 4/9/15 1:42 PM


1An Introduction to Critical Thinking and Logic

Hemera Technologies/Ablestock.com/Thinkstock

Learning Objectives After reading this chapter, you should be able to:

1. Explain the importance of critical thinking and logic.

2. Describe the relationship between critical thinking and logic.

3. Explain why logical reasoning is a natural human attribute that we all have to develop as a skill.

4. Identify logic as a subject matter applicable to many other disciplines and everyday life.

5. Distinguish the various uses of the word argument that do not pertain to logic.

6. Articulate the importance of language in logical reasoning.

7. Describe the connection between logic and philosophy.

har85668_01_c01_001-024.indd 1 4/9/15 11:19 AM

Section 1.1 What Is Critical Thinking?

This book will introduce you to the tools and practices of critical thinking. Since the main tool for critical thinking is logical reasoning, the better part of this book will be devoted to discuss- ing logic and how to use it effectively to become a critical thinker.

We will start by examining the practical importance of critical thinking and the virtues it requires us to nurture. Then we will explore what logic is and how the tools of logic can help us lead easier and happier lives. We will also briefly review a critical concept in logic—the argument—and discuss the importance of language in making good judgments. We will con- clude with a snapshot of the historical roots of logic in philosophy.

1.1 What Is Critical Thinking? What is critical thinking? What is a critical thinker? Why do you need a guide to think criti- cally? These are good questions, but ones that are seldom asked. Sometimes people are afraid to ask questions because they think that doing so will make them seem ignorant to others. But admitting you do not know something is actually the only way to learn new things and better understand what others are trying to tell you.

There are differing views about what critical thinking is. For the most part, people take bits and pieces of these views and carry on with their often imprecise—and sometimes conflicting— assumptions of what critical thinking may be. However, one of the ideas we will discuss in this book is the fundamental importance of seeking truth. To this end, let us unpack the term critical thinking to better understand its meaning.

First, the word thinking can describe any number of cognitive activities, and there is certainly more than one way to think. We can think analytically, creatively, strategically, and so on (Sousa, 2011). When we think analytically, we take the whole that we are examining—this could be a term, a situation, a scientific phenomenon—and attempt to identify its components. The next step is to examine each component individually and understand how it fits with the other com- ponents. For example, we are currently examining the meaning of each of the words in the term critical thinking so we can have a better understanding of what they mean together as a whole.

Analytical thinking is the kind of thinking mostly used in academia, science, and law (includ- ing crime scene investigation). In ordinary life, however, you engage in analytical thinking more often than you imagine. For example, think of a time when you felt puzzled by some- one else’s comment. You might have tried to recall the original situation and then parsed out the language employed, the context, the mood of the speaker, and the subject of the com- ment. Identifying the different parts and looking at how each is related to the other, and how together they contribute to the whole, is an act of analytical thinking.

When we think creatively, we are not focused on relationships between parts and their wholes, as we are when we think analytically. Rather, we try to free our minds from any boundaries such as rules or conventions. Instead, our tools are imagination and innovation. Suppose you are cooking, and you do not have all the ingredients called for in your recipe. If you start thinking creatively, you will begin to look for things in your refrigerator and pantry that can substitute for the missing ingredients. But in order to do this, you must let go of the recipe’s expected outcome and conceive of a new direction.

har85668_01_c01_001-024.indd 2 4/9/15 11:19 AM

Section 1.1 What Is Critical Thinking?

When we think strategically, our focus is to first lay out a master plan of action and then break it down into smaller goals that are organized in such a way as to support our outcomes. For exam- ple, undertaking a job search involves strategic planning. You must identify due dates for applications, request let- ters of recommendations, prepare your résumé and cover letters, and so on. Thinking strategically likely extends to many activities in your life, whether you are going grocery shopping or planning a wedding.

What, then, does it mean to think criti- cally? In this case the word critical has nothing to do with criticizing others in a negative way or being surly or cynical.

Rather, it refers to the habit of carefully evaluating ideas and beliefs, both those we hear from others and those we formulate on our own, and only accepting those that meet certain stan- dards. While critical thinking can be viewed from a number of different perspectives, we will define critical thinking as the activity of careful assessment and self-assessment in the process of forming judgments. This means that when we think critically, we become the vigilant guard- ians of the quality of our thinking.

Simply put, the “critical” in critical thinking refers to a healthy dose of suspicion. This means that critical thinkers do not simply accept what they read or hear from others—even if the information comes from loved ones or is accompanied by plausible-sounding statistics. Instead, critical thinkers check the sources of information. If none are given or the sources are weak or unreliable, they research the information for themselves. Perhaps most importantly, critical thinkers are guided by logical reasoning.

As a critical thinker, always ask yourself what is unclear, not understood, or unknown. This is the first step in critical thinking because you cannot make good judgments about things that you do not understand or know.

The Importance of Critical Thinking Why should you care about critical thinking? What can it offer you? Suppose you must make an important decision—about your future career, the person with whom you might want to spend the rest of your life, your financial investments, or some other critical matter. What considerations might come to mind? Perhaps you would wonder whether you need to think about it at all or whether you should just, as the old saying goes, “follow your heart.” In doing so, you are already clarifying the nature of your decision: purely rational, purely emotional, or a combination of both.


Critical thinking involves carefully assessing information and its sources.

har85668_01_c01_001-024.indd 3 4/9/15 11:19 AM

Section 1.1 What Is Critical Thinking?

In following this process you are already starting to think critically. First you started by asking questions. Once you examine the answers, you would then assess whether this information is sufficient, and perhaps proceed to research further information from reli- able sources. Note that in all of these steps, you are making distinctions: You would distinguish between relevant and irrelevant questions, and from the relevant questions, you would distin- guish the clear and precise ones from the others. You also would distinguish the answers that are helpful from those that are not. And finally, you would separate out the good sources for your research, leaving aside the weak and biased ones.

Making distinctions also determines the path that your examination will follow, and herein lies the connection between critical thinking and logic. If you decide you should examine the best reasons that support each of the possible options available, then this choice takes you in the direction of logic. One part of logical reasoning is the weighing of evidence. When making an important decision, you will need to identify which factors you consider favorable and which you consider unfavorable. You can then see which option has the strongest evidence in its favor (see Everyday Logic: Evidence, Beliefs, and Good Thinking for a discussion of the importance of evidence).

Consider the following scenario. You are 1 year away from graduating with a degree in busi- ness. However, you have a nagging feeling that you are not cut out for business. Based on your research, a business major is practical and can lead to many possibilities for well-paid employment. But you have discovered that you do not enjoy the application or the analysis of quantitative methods—something that seems to be central to most jobs in business. What should you do?

Many would seek advice from trusted people in their lives—people who know them well and thus theoretically might suggest the best option for them. But even those closest to us can offer conflicting advice. A practical parent may point out that it would be wasteful and possibly risky to switch to another major with only 1 more year to go. A reflective friend may point out that the years spent studying business could be considered simply part of a journey of self-discovery, an investment of time that warded off years of unhappiness after gradua- tion. In these types of situations, critical thinking and logical reasoning can help you sort out competing considerations and avoid making a haphazard decision.

We all find ourselves at a crossroads at various times in our lives, and whatever path we choose will determine the direction our lives will take. Some rely on their emotions to help them make their decisions. Granted, it is difficult to deny the power of emotions. We recall more vividly those moments or things in our lives that have had the strongest emotional


Can you recall a time when you acted or made a decision while you were experiencing strong emotions? Relying on our emotions to make decisions undermines our ability to develop confidence in our rational judgments. Moreover, emotional decisions cannot typically be justified and often lead to regret.

har85668_01_c01_001-024.indd 4 4/9/15 11:19 AM

Section 1.1 What Is Critical Thinking?

impact: a favorite toy, a first love, a painful loss. Many interpret gut feelings as revelations of what they need to do. It is thus easy to assume that emotions can lead us to truth. Indeed, emotions can reveal phenomena that may be otherwise inaccessible. Empathy, for example, permits us to share or recognize the emotions that others are experiencing (Stein, 1989).

The problem is that, on their own, emotions are not reliable sources of information. Emotions can lead you only toward what feels right or what feels wrong—but cannot guarantee that what feels right or wrong is indeed the right or wrong thing to do. For example, acting self- ishly, stealing, and lying are all actions that can bring about good feelings because they satisfy our self-serving interests. By contrast, asking for forgiveness or forgiving someone can feel wrong because these actions can unleash feelings of embarrassment, humiliation, and vulner- ability. Sometimes emotions can work against our best interests. For example, we are often fooled by false displays of goodwill and even affection, and we often fall for the emotional appeal of a politician’s rhetoric.

The best alternative is the route marked by logical reasoning, the principal tool for developing critical thinking. The purpose of this book is to help you learn this valuable tool. You may be wondering, “What’s in it for me?” For starters, you are bound to gain the peace of mind that comes from knowing that your decisions are not based solely on a whim or a feeling but have the support of the firmer ground of reason. Despite the compelling nature of your own emo- tional barometer, you may always wonder whether you made the right choice, and you may not find out until it is too late. Moreover, the emotional route for decision making will not help you develop confidence in your own judgments in the face of uncertainty.

In contrast, armed with the skill of logical reasoning, you can lead a life that you choose and not a life that just happens to you. This power alone can make the difference between a happy and an unhappy life. Mastering critical thinking results in practical gains—such as the ability to defend your views without feeling intimidated or inadequate and to protect yourself from manipulation or deception. This is what’s in it for you, and this is only the beginning.

Everyday Logic: Evidence, Beliefs, and Good Thinking

It is wrong always, everywhere, and for anyone to believe anything on insufficient evidence. —W. K. Clifford (1879, p. 186)

British philosopher and mathematician W. K. Clifford’s claim—that it is unethical to believe anything if you do not have sufficient evidence for it—elicited a pronounced response from the philosophical community. Many argued that Clifford’s claim was too strong and that it is acceptable to believe things for which we lack the requisite evidence. Whether or not one absolutely agrees with Clifford, he raises a good point. Every day, millions of people make deci- sions based on insufficient evidence. They claim that things are true or false without putting in the time, effort, and research necessary to make those claims with justification.

You have probably witnessed an argument in which people continue to make the same claims until they either begin to become upset or merely continue to restate their positions without adding anything new to the discussion. These situations often devolve and end with state- ments such as, “Well, I guess we will just agree to disagree” or “You are entitled to your opin- ion, and I am entitled to mine, and we will just have to leave it at that.” However, upon further reflection we have to ask ourselves, “Are people really entitled to have any opinion they want?”


har85668_01_c01_001-024.indd 5 4/9/15 11:19 AM

Section 1.1 What Is Critical Thinking?

From the perspective of critical thinking, the answer is no. Although people are legally entitled to their beliefs and opinions, it would be intellectually irresponsible of them to feel entitled to an opinion that is unsupported by logical reasoning and evidence; people making this claim are conflating freedom of speech with freedom of opinion. A simple example will illustrate this point. Suppose someone believes that the moon is composed of green cheese. Although he is legally entitled to his belief that the moon is made of green cheese, he is not rationally entitled to that belief, since there are many reasons to believe and much evidence to show that the moon is not composed of green cheese.

Good thinkers constantly question their beliefs and examine multiple sources of evidence to ensure their beliefs are true. Of course, people often hold beliefs that seem warranted but are later found not to be true, such as that the earth is flat, that it is acceptable to paint baby cribs with lead paint, and so on. However, a good thinker is one who is willing to change his or her views when those views are proved to be false. There are certain criteria that must be met for us to claim that someone is entitled to a specific opinion or position on an issue.

There are other examples where the distinction is not so clear. For instance, some people believe that women should be subservient to men. They hold this belief for many reasons, but the pre- dominant one is because specific religions claim this is the case. Does the fact that a religious text claims that women should serve men provide sufficient evidence for one to believe this claim? Many people believe it does not. However, many who interpret their religious texts in this man- ner would claim that these texts do provide sufficient evidence for such claims.

It is here that we see the danger and difficulty of providing hard-and-fast definitions of what constitutes sufficient evidence. If we believe that written words in books came directly from divine sources, then we would be prone to give those words the highest credibility in terms of the strength of their evidence. However, if we view written words as arguments presented by their authors, then we would analyze the text based on the evidence and reasoning presented. In the latter case we would find that these people are wrong and that they are merely making claims based on their cultural, male-dominated environments.

Of course, all people have the freedom to believe what they want. However, if we think of entitlement as justification, then we cannot say that all people are entitled to their opinions and beliefs. As you read this book, think about what you believe and why. If you do not have reasons or supporting evidence for your beliefs and opinions, you should attempt to find it. Try not to get sucked into arguments without having evidence. Most important, as a good thinker, you should be willing and able to admit the strengths and weaknesses of various posi- tions on issues, especially your own. At the same time, if in your search for evidence you find that the opposing position is the stronger one, you should be willing to change your position. It is also a sign of good thinking to suspend judgment when you suspect that the arguments of others are not supported by evidence or logical reasoning. Suspending judgment can protect you from error and making rash decisions that lead to negative outcomes.

Everyday Logic: Evidence, Beliefs, and Good Thinking (continued)

Becoming a Critical Thinker By now it should be clear that critical thinking is an important life skill, one that will have a decisive impact on our lives. It does not take luck or a genetic disposition to be a critical thinker. Anyone can master critical thinking skills. So how do you become a critical thinker? Earlier in

har85668_01_c01_001-024.indd 6 4/9/15 11:19 AM

Section 1.2 Three Misconceptions About Logic

the chapter, logical reasoning was described as the main tool for critical thinking. Thus, the most fundamental step in becoming a critical thinker is to recognize the importance of reason as the filter for your beliefs and actions. Once you have done this, you will be in the right frame of mind to start learning about logic and identify what tools of logic are at your disposal.

It is also important to note that becoming a critical thinker demands intellectual modesty. We can understand intellectual modesty as the willingness to put our egos in check because we see truth seeking as a far greater and more satisfying good than seeking to be right. Critical thinkers do not care about seeking approval by trying to show that they are right. They do not assume that disagreement reflects a lack of intelligence or insight. Being intellectually modest means recognizing not only that we can make mistakes, but also that we have much to learn. If we are (a) aware that we are bound to make mistakes and that we will benefit when we recognize them; (b) willing to break old habits and embrace change; and, perhaps most importantly, (c) genuinely willing to know what others think, then we can be truly free to experience life as richly and satisfactorily as a human being can.

1.2 Three Misconceptions About Logic If logic is so important to critical thinking, we must of course examine what logic is. This task is not as easy as it sounds, and before we tackle it we must first dismantle some common misconceptions about the subject.

Logic Is for Robots The first misconception is that it is not normal for humans to display a command of logic. (In fact, some suggest that humans created, rather than discovered, these patterns of thought; see A Closer Look: Logic: A Human Invention?) Think of how popular culture and media often depict characters endowed with logical reasoning. In American slang they are the eggheads, the geeks, the nerds, the ones who can use their minds but have trouble relating to other people. Such people often lack compassion or social charisma, or they are emotionally unex- pressive. They are only logical and lack the blend of attributes that people actually have.

Consider the logically endowed characters on the Star Trek series. Vulcans, for example, are beings who suppress all emotions in favor of logic because they believe that emotions are dangerous. What appear to be heartless decisions by the Vulcans no doubt make logic seem quite unsavory to some viewers. The android Data—from The Next Generation series in the Star Trek franchise—is another example. Data’s positronic brain is devoid of any emotional capacity and thus processes all information exclusively by means of a logical calculus. Logic is thus presented as a source of alienation, as Data yearns for the affective depth that his human colleagues experience, such as humor and love.

Such presentations of logic as the polar opposite of emotion are false dichotomies because all human beings are naturally endowed with both logical and emotional faculties—not just one or the other. In other words, we have a broader range of abilities than that for which we give

har85668_01_c01_001-024.indd 7 4/9/15 11:19 AM

Section 1.2 Three Misconceptions About Logic

ourselves credit. So if you think that you are mostly emotional, then you simply have yet to discover your logical side.

Nonetheless, some believe emotions are the fundamental mark of human beings. It is quite likely that emotion has played a significant role in our survival as a species. Neuroscientists, for example, have discovered that our emotions have a faster pathway to the action centers of the brain than the methodical decision-making approach of our logical faculties (LeDoux, 1986, 1992). It pays, for example, to give no thought to running if we fear we are being hunted by a predator.

In most human civilizations today, however, dodging predators is not a main necessity. In fact, methodical reasoning is more advantageous in most of today’s situations. Thinking things through logically assists learning at all levels, produces better results in the job market (in seeking jobs, obtaining promotions, and procuring raises), and helps us make better choices. As noted in the previous section, we are more likely to be satisfied and experience fewer regrets if we reason carefully about our most critical choices in life. Indeed, logical reasoning can prove to be a better strategy for attaining the individual quest for personal fulfillment than any available alternative such as random choice, emotional impulse, waiting and seeing, and so on.

Moral of the Story: Emotions Versus Logic Embracing logical reasoning does not mean disregarding our emotions altogether. Instead, we should recognize that emotions and logic are both essential components of what it is to be human.

A Closer Look: Logic: A Human Invention? One objection to the use of logic—often from what is known as a postmodern perspective—is that logic is a human invention and thus inferior to emotions or intuitions. In other words, what some call the “rules of logic” cannot be seen as univer- sally applicable because logic originated in the Western world; thus, logic is relative and only a matter of perspective.

For example, the invention of chairs seems indispensable to those of us who live where chairs have become part of our cultural background. But those from different cultural back- grounds or those who lived during different time periods may not use chairs at all, or may employ alternative seating devices, such as the traditional Japanese tatami mats. To broadly apply the concept of chair as an appropriate place to sit would be ethnocentric, or applying the standards of one’s own culture to all other cultures.

In response to the foregoing objection, the authors of this text argue that logic is not a human invention, nor a conven- tion that spread in certain parts of the world. Rather, logic was

Fine Art Images/SuperStock

Aristotle’s Organon is a compilation of six treatises in which Aristotle formulated principles that laid the foundation for the field of logic.


har85668_01_c01_001-024.indd 8 4/9/15 11:20 AM

Section 1.2 Three Misconceptions About Logic

discovered in people’s ordinary encounters with reality, as early as antiquity. Based on avail- able historical records, the first study of the principles at work in good reasoning emerged in ancient Greece. Aristotle was the first to formulate principles of logic, and he did so in six treatises that ancient commentators grouped together under the title Organon, which means “instrument” (reflecting the view that logic is the fundamental instrument for philosophy, which will be discussed later in the chapter).

Importantly, other civilizations have developed logic independently of the Greek tradition. For example, Dignaga was an important thinker in India who lived a few hundred years after Aristotle. Dignaga’s work begins with certain practices of debate within the Nyaya school of Hinduism and transitions to a more formal approach to reasoning. Although the result of Dig- naga’s studies is not identical to Aristotle’s, there is enough similarity to strongly suggest that basic logical principles are not merely cultural artifacts.

In the Middle Ages, Aristotelian logic was brought to the West by Islamic philosophers and thus became part of the scholarship of Christian philosophers until the 14th or 15th century. The emergence of modern logic did not take place until the 19th and 20th centuries, during which new ways of analyzing propositions gave rise to new discoveries concerning the foun- dations of mathematics, as well as a new system of logical notation and a new system of logical principles that replaced the Aristotelian system.

Thus, the examination of good reasoning was fundamental in the development of human civi- lization. Logical reasoning has helped us to identify the laws that guide physical phenomena, which brought us to the state of technological advancement that we experience today. How else could we have erected pyramids and other marvels in the ancient world without having discovered a principle for checking the accuracy of the geometry employed to design them?

Logic Does Not Need to Be Learned A second misconception is that logic does not need to be learned. After all, humankind’s unique distinction among other animals is the faculty of rationality and abstract thought. Although many nonhuman animals have very high levels of intelligence, to the best of our knowledge, abstract thought seems to be the mark of humankind’s particular brand of rationality. Today the applications of logical reasoning are all around us. We are able to experience air travel and marvel at rockets in space. We are also able to enjoy cars, sky- scrapers, computers, cell phones, air-conditioning, home insulation, and even smart homes that allow users to regulate light, temperature, and other functions remotely via smart- phones and other devices. Logical reasoning has afforded us an increasingly better picture of reality, and as a result, our lives have become more comfortable.

However, if logical reasoning is a natural human trait, then why should anyone have to learn it? We certainly experience emotions without any need to be trained, so why would the case be different with our rational capacities? Consider the difference between natural capacities that are nonvoluntary or automatic, on the one hand, and natural capacities that involve our will, on the other. Swallowing, digesting, and breathing are nonvoluntary natural capacities, as are emotions. We usually do not will ourselves to feel happy, angry, or excited. Rather, we usually just find ourselves feeling happy, angry, or excited.

A Closer Look: Logic: A Human Invention? (continued)

har85668_01_c01_001-024.indd 9 4/9/15 11:20 AM

Section 1.2 Three Misconceptions About Logic

Now contrast these with voluntary natural capacities such as walking, running, or sitting. We usually need to will these actions in order for them to take place. We do not just find ourselves running without intending to run, as is the case with swallowing, breathing, or feeling excited or angry. If logic were akin to breathing, the world would likely look like a different place.

Logic is practiced with intention and must be learned, just like we learn to walk, sit, and run. True, almost everyone learns to run to some degree as part of the normal process of growing up. Similarly, almost everyone learns a certain amount of logical reasoning as they move from infant to adult. However, to be a good runner, you need to learn and practice specific skills. Similarly, although everyone has some ability in logic, becoming a good critical thinker requires learning and practicing a range of logical skills.

Logic Is Too Hard The final misconception is that logic is too hard or difficult to learn. If you have survived all these years without studying logic, you might wonder why you should learn it now. It is true that learning logic can be challenging and that it takes time and effort before it feels like second nature. But consider that we face the same challenge whenever we learn anything new, whether it is baking, automotive repair, or astrophysics. These are all areas of human knowledge that have a specific terminology and methodology, and you cannot expect to know how to bake a soufflé, fix a valve cap leak, or explain black holes without any investment in learning the subject matter.

Let us return to our running analogy. Just as we must intend to run in order to do it, we must intend to think methodically in order to do it. When we become adept at running, we do not have to put in as much effort or thought. A fit body can perform physical tasks more easily than an unfit one. The mind is no different. A mind accustomed to logical reasoning will find activities of the intellect easier than an unfit one. The best part is that if you wish to achieve logical fitness, all you need to do is learn and practice the necessary tools for it. The purpose of this book is to guide you toward this goal.

Without a doubt, learning logic will be challenging. But keep in mind that starting a logical fitness program is very much like starting a physical fitness program: There will be a little pain in the beginning. When out-of-shape muscles are exercised, they hurt. You might find that some lessons or concepts might give you a bit of trouble. When this happens, don’t give up! In a physical fitness program, we know that if we keep going, over time the pain goes

Moral of the Story: Logic as a Skill Having a natural capacity for something does not amount to being good at it. Even as emotions seem to come so naturally, some people have to work at being less sensitive or more empa- thetic. The same is true for logical reasoning.

har85668_01_c01_001-024.indd 10 4/9/15 11:20 AM

Section 1.3 What Is Logic?

away, the muscles get in shape, and movement becomes joyful. Likewise, as you keep working diligently on learning and developing your natural logical abilities, you will discover that you understand new things more easily, reading is less of a struggle for you, and logical reasoning is actually fun and rewarding. Eventually, you will begin to recognize logical connections (or the lack thereof) that you did not previously notice, make decisions that you are less likely to regret, and develop the confidence to defend the positions you hold in a way that is less emotionally taxing.

1.3 What Is Logic? Having dispelled some common misconceptions, we can now occupy ourselves with a funda- mental question for this book: What is logic? A first attempt to define logic might be to say that it is the study of the methods and principles of good reasoning. This definition implies that there are certain principles at work in good reasoning and that certain methods have been developed to encourage it. It is important to clarify that these principles and methods are not a matter of opinion. They apply to someone in your hometown as much as to someone in the smallest village on the other side of the world. Furthermore, they are as suitable today as they were 200 or 2,000 years ago.

This definition is a good place to start, but it leaves open the questions of what we mean by “good reasoning” and what makes some reasoning good relative to others. Although it is admittedly difficult to cram answers to all possible questions into a pithy statement, defini- tions should attempt to be more specific. In this book, we shall employ the following defini- tion: Logic is the study of arguments that serve as tools for arriving at warranted judgments. Notice that this definition states how logic can be of service to you now, in your daily routine, and in whatever occupation you hold. To understand how this is the case, let us unpack this definition a bit.

The Study of Arguments This definition of logic does not explain that there are principles at work in good reasoning or that these princi- ples are not necessarily informed by experience: The meaning of the word argument in logic does the job. Argu- ment has a very technical meaning in logic, and for this reason, Chapter 2 is dedicated entirely to the definition of arguments—what they are, what they are not, what they consist of, and what makes them good. Later in this chap- ter, we will survey other meanings for the word argument outside of logic. Purestock/Thinkstock

In logic, an argument is the methodical presentation of one’s position on a topic, not a heated fight with another person.

har85668_01_c01_001-024.indd 11 4/9/15 11:20 AM

Section 1.3 What Is Logic?

For now, let us refer to an argument as a methodical defense of a position. Suppose that Diana is against a proposed increase in the tax rate. She decides to write a letter to the editor to pres- ent her reasons why a tax increase would be detrimental to all. She researches the subject, including what economists have to say about tax increases and the position of the opposition. She then writes an informed defense of her position. By advancing a methodical defense of a position, Diana has prepared an argument.

A Tool for Arriving at Warranted Judgments For our purposes, the word judgment refers simply to an informed evaluation. You examine the evidence with the goal of verifying that if it is not factual, it is at least probable or theo- retically conceivable. When you make a judgment, you are determining whether you think something is true or false, good or bad, right or wrong, beautiful or ugly, real or fake, delicious or disgusting, fun or boring, and so on. It is by means of judgments that we furnish our world of beliefs. The richer our world of beliefs, the clearer we can be about what makes us happy. Judgments are thus very important, so we need to make sure they are sound.

What about the word warrant? Why are warranted judgments preferable to unwarranted ones? What is a warrant? If you are familiar with the criminal justice system or television crime dramas, you may know that a warrant is an authoritative document that permits the search and seizure of potential evidence or the arrest of a person believed to have commit- ted a crime. Without a warrant, such search and seizure, as well as coercing an individual to submit to interrogation or imprisonment, is a violation of the protections and rights that individuals in free societies enjoy. The warrant certifies that the search or arrest of a person is justified—that there is sufficient reason or evidence to show that the search or arrest does not unduly violate the person’s rights. More generally, we say that an action is warranted if it is based on adequate reason or evidence.

Accordingly, our judgments are warranted when there is adequate reason or evidence for making them. In contrast, when we speak of something being unwarranted, we mean that it lacks adequate reason or evidence. For example, unwarranted fears are fears we have without good reason. Children may have unwarranted fears of monsters under their beds. They are afraid of the monsters, but they do not have any real evidence that the monsters are there. Our judgments are unwarranted when, like a child’s belief in lurking monsters under the bed, there is little evidence that they are actually true.

In the criminal justice system, the move from suspicion to arrest must be warranted. Simi- larly, in logic, the move from grounds to judgment must be warranted (see A Closer Look: War- rants for the Belief in God for an example). We want our judgments to be more like a properly executed search warrant than a child’s fear of monsters. If we fail to consider the grounds for our judgments, then we are risking our lives by means of blind decisions; our judgments are no more likely to give us true beliefs than false ones. It is thus essential to master the tools for arriving at warranted judgments.

It is important to recognize the urgency for obtaining such mastery. It is not merely another nice thing to add to the bucket list—something we will get around to doing, right after we trek to the Himalayas. Rather, mastering the argument—the fundamental tool for arriving at

har85668_01_c01_001-024.indd 12 4/9/15 11:20 AM

Section 1.3 What Is Logic?

A Closer Look: Warrants for the Belief in God Striving for warranted judgments might seem difficult when it comes to beliefs that we have accepted on faith. Note that not all that we accept on faith is necessarily related to God or religion. For example, we likely have faith that the sun will rise tomorrow, that our spouses are honest with us, and that the car we parked at the mall will still be there when we return from shopping. Many American children have faith that the tooth fairy will exchange money for baby teeth and that Santa Claus will bring toys come Christmas. Are we reasoning correctly by judging such beliefs as warranted? Whatever your answer in regard to these other issues, questions of religious belief are more likely to be held up as beyond the reach of logic. It is important to recognize this idea is far from being obviously true. Many deeply religious people have nonetheless found it advisable to offer arguments in support of their beliefs.

One such individual was Thomas Aquinas, a 13th-century Roman Catholic Dominican priest and philosopher. In his Summa Theo- logica (Aquinas, 1947), he advanced five logical arguments for God’s existence that do not depend on faith.

The 20th-century Oxford scholar and Christian apologist C. S. Lewis, perhaps best known for the popular children’s series The Chronicles of Narnia, did not embrace his Anglican religion until he was in his thirties. In his books Mere Christianity and Miracles: A Preliminary Study, he employs reason to defend Christian beliefs and the logical possibility of miracles.

There are, of course, many more examples. The important point to draw from this is that all of our judgments of faith—from the faith in the sun rising tomorrow to the faith in the exis- tence of God—should be warranted beliefs and not just beliefs that we readily accept without question. In other words, even faith should make sense in order to be able to communicate such beliefs to those who do not share those beliefs. Note that philosophers who have pre- sented arguments in defense of their religious views have helped transform the nature of reli- gious disagreement to one in which the differences are generally debated in an intellectually enlightening way.

We have not yet reached the point in which differences in religious views are no longer the cause of wars or killing. Nonetheless, the power of argument in the formation of our beliefs is that it supports social harmony despite diversity and disagreement in views, and we all gain from presenting our unique positions in debated issues.


In his Summa Theologica, Thomas Aquinas advanced the idea that belief in the existence of God can be grounded in logical argument.

warranted judgments—is as essential as learning to read and write. Knowledge of logic is a relatively tiny morsel of information compared to all that you know thus far, but it has the capacity to change your life for the better.

har85668_01_c01_001-024.indd 13 4/9/15 11:20 AM

Section 1.4 Arguments Outside of Logic

Formal Versus Informal Logic Logic is a rich and complex field. Our focus here will be how logic contributes to the develop- ment and honing of critical thinking in everyday life. Primarily, the concepts we will discuss will reflect principles of informal logic. The principal aim in informal logic is to examine the reasoning we employ in the ordinary and everyday claims we make.

In contrast, formal logic is far more abstract, often involving the use of symbols and math- ematics to analyze arguments. Although this text will touch on a few formal concepts of logic in its discussions of deduction (see Chapter 3 and Chapter 4), the purpose in doing so is to develop methodology for good reasoning that is directly applicable to ordinary life.

1.4 Arguments Outside of Logic Although Chapter 2 will explore the term argument in more detail, it is important to clarify that the word is not exclusive to logic. Its meaning varies widely, and you may find that one of the descriptions in this section fits your own understanding of what is an argument. Knowing there is more than one meaning of this word, depending on context or application, will help you correctly understand what is meant in a given situation.

Arguments in Ordinary Language Often, we apply the word argument to an exchange of diverging views, sometimes in a heated, angry, or hostile setting. Suppose you have a friend named Lola, and she tells you, “I had an argument with a colleague at work.” In an ordinary setting you might be correct in under- standing Lola’s meaning of the term argument as equivalent to a verbal dispute. In logic, how- ever, an argument does not refer to a fight or an angry dispute. Moreover, in logic an argument does not involve an exchange between two people, and it does not necessarily have an emo- tional context.

Although in ordinary language an argument requires that at least two or more people be involved in an exchange, this is not the case in logic. A logical argument is typically advanced by only one person, either on his or her behalf or as the representative of a group. No exchange is required. Although an argument may be presented as an objection to another person’s point of view, there need not be an actual exchange of opposing ideas as a result.

Now, if two persons coordinate a presentation of their defenses of what can be identified as opposing points of view, then we have a debate. A debate may contain several arguments but is not itself an argument. Accordingly, only debates are exchanges of diverging views.

Even if a logical argument is both well supported and heartfelt, its emotional context is not its driving force. Rather, any emotion that may be inevitably tied in with the defense of the argu- ment’s principal claim is secondary to the reasons advanced. But let us add a little contextual reference to the matter of debates. If the arguments on each side of the debate are presented

har85668_01_c01_001-024.indd 14 4/9/15 11:20 AM

Section 1.4 Arguments Outside of Logic

well, then the debate may lead to the discovery of perspectives that each party had not pre- viously considered. As such, debates can be quite enlightening because every time our own perspective is broadened with ideas not previously considered and that are well supported and defended, it is very difficult for the experience to be negative. Instead, a good debate is an intellectually exhilarating experience, regardless of how attached one may be to the side one is defending.

Not even debates need to be carried out with an angry or hostile demeanor, or as a means to vent one’s frustration or other emotions toward the opposition. To surrender to one’s emo- tions in the midst of a debate can cause one to lose track of the opposition’s objections and, consequently, be able to muster only weak rebuttals.

Rhetorical Arguments Think about how politicians might try to persuade you to vote for them. They may appeal to your patriotism. They may suggest that if the other candidate wins, things will go badly. They may choose words and examples that help specific audiences feel like the politician empathizes with their situation. All of these techniques can be effective, and all are part of what someone who studies rhetoric—the art of persuasion—might include under the term argument.

Rhetoric is a field that uses the word argument almost as much as logic does. You are likely to encounter this use in English, communication, composition, or argumentation classes. From the point of view of rhetoric, an argument is an attempt to persuade—to change someone’s opinion or behavior. Because the goal of a rhetorical argument is persuasion, good arguments are those that are persuasive. In fact, any time someone attempts to persuade you to do some- thing, they can be seen as advancing an argument in this sense.

Moral of the Story: Defining the Word Argument To avoid conflating the two widely different uses of the word argument (that is, as a dis- pute in ordinary language and as a defense of a point of view in logic) is to use the word only in its classical sense. In its classical meaning, an argument does not refer to a vehicle to express emotions, complaints, insults, or provocations. For these and all other related meanings, there are a wide variety of terms that would do a better job, such as disagree- ment, quarrel, bicker, squabble, fight, brawl, altercation, having words, insult match, word combat, and so on. The more precise we are in our selection of words, the more efficient our communications.

har85668_01_c01_001-024.indd 15 4/9/15 11:20 AM

Section 1.4 Arguments Outside of Logic

Think about how you might have persuaded a sibling to do something for you when you were young. You might have offered money, tried to manipulate with guilt-inducing tactics, appealed to his or her sense of pride or duty, or just attempted to reason with him or her. All of these things can be motivating, and all may be part of a rhetorical approach to argu- ments. However, while getting someone to do something out of greed, guilt, pride, or pity can indeed get you what you want, this does not mean you have succeeded in achieving a justified defense of your position.

Some of the most impressive orators in history—Demosthenes, Cicero, Winston Churchill— were most likely born with a natural talent for rhetoric, yet they groomed their talent by becom- ing well educated and studying the speeches of previous great orators. Rhetoric depends not only on the mastery of a language and broad knowledge, but also on the fine-tuning of the use of phrases, metaphors, pauses, crescendos, humor, and other devices. However, a talent for rheto- ric can be easily employed by unscrupulous people to manipulate others. This characteristic is precisely what distinguishes rhetorical arguments from arguments in logic.

Whereas rhetorical arguments aim to persuade (often with the intent to manipulate), logical arguments aim to demonstrate. The distinction between persuading and demonstrating is crucial. Persuading requires only the appearance of a strong position, perhaps camouflaged by a strong dose of emotional appeal. But demonstrating requires presenting a position in a way that may be conceivable even by opponents of the position. To achieve this, the argument must be well informed, supported by facts, and free from flawed reasoning. Of course, an argument can be persuasive (meaning, emotionally appealing) in addition to being logically strong. The important thing to remember is that the fundamental end of logical arguments is not to persuade but to employ good reasoning in order to demonstrate truths.

Revisiting Arguments in Logic Suppose you and your friend watch a political debate, and she tells you that she thought one of the candidates gave a good argument about taxes. You respond that you thought the can- didate’s argument was not good. Have you disagreed with each other? You might think that you had, but you may just be speaking past each other, using the term argument in different senses. Your friend may mean that she found the argument persuasive, while you mean that the argument did not establish that the candidate’s position was true. It may turn out that you both agree on these points. Perhaps the candidate gave a rousing call to action regarding tax reform but did not spend much time spelling out the details of his position or how it would work to solve any problems. In this sort of case, the candidate may have given a good argu- ment in the rhetorical sense but a bad argument in the logical sense.

Moral of the Story: Persuasion Versus Demonstration Purely persuasive arguments are undoubtedly easier to advance, which makes them the per- fect tool for manipulation and deceit. However, only arguments that demonstrate with logic serve the end of pursuing truth; thus, they are the preferable ones to master.

har85668_01_c01_001-024.indd 16 4/9/15 11:20 AM

Section 1.5 The Importance of Language in Logic

To summarize:

• In contrast to ordinary arguments, logical arguments do not involve an exchange of any kind.

• In contrast to ordinary arguments and rhetorical arguments, logical arguments are not driven by emotions. In logic, only the reasons provided in defense of the conclu- sion make up the force of the argument.

• In contrast to rhetorical arguments, logical arguments are not primarily attempts to persuade, because there is no attempt to appeal to emotions. Rather, logical argu- ments attempt only to demonstrate with reasons. Of course, good logical arguments may indeed be persuasive, but persuasion is not the primary goal.

The goal of an argument in logic is to demonstrate that a position is likely to be true.

So before you go on to have a quarrel with your friend, make sure you are both using the word in the same way. Only then can you examine which sense of argument is the most crucial to the problem raised. Should we vote for a candidate who can get us excited about important issues but does not tell us how he or she proposes to solve them? Or shall we vote for a can- didate who may not get us very excited but who clearly outlines how he or she is planning to solve the nation’s problems?

In the rest of this book, you should read the word argument in the logical sense and no other. If the word is ever used in other ways, the meaning will be clearly indicated. Furthermore, outside of discussions of logic, you must clarify how the word is being used.

1.5 The Importance of Language in Logic The foregoing distinction of the different uses and meanings of the word argument show the importance of employing language precisely. In addition to creating misunderstandings, mis- used words or the lack of knowledge of distinctions in meaning also prevent us from formulat- ing clear positions about matters that pertain to our personal goals and happiness. Language affects how we think, what we experience, how we experience it, and the kind of lives we lead.

Language is our most efficient means of communicating what is in our minds. However, it is not the only means by which humans communicate. We also communicate via facial expres- sions, gestures, and emotions. However, these nonverbal cues often need clarifying words so we can clearly grasp what someone else is expressing or feeling, especially people we don’t know very well. If we see a stranger crying, for example, we might not be able to distinguish at first glance if the tears are from happiness or sadness. If we are visiting a foreign land and hear a man speaking in a loud voice and gesturing wildly, we might not know if he is quarrel- ling or just very enthusiastic unless we understand his language.

This suggests that words matter very much because they are the universal means for making ourselves clear to others. This may seem obvious, since we all use language to communi- cate and, generally speaking, seem to manage satisfactorily. What we do not often recognize,

har85668_01_c01_001-024.indd 17 4/9/15 11:20 AM

Section 1.5 The Importance of Language in Logic

however, is the difference we could experience if we took full advantage of clear and precise language in its optimal form. One result could be that many will no longer ignore what we say. Another could be that as our vocabulary expands, we will no longer be limited to what we can express to others or in what we can grasp from our experiences.

Suppose, for example, that you are invited to a dinner that unbeknownst to you introduces you to a spice you have never tasted before. As you savor the food on your plate, you may taste something unfamiliar, but the new flavor may be too faint for you, amidst the otherwise famil- iar flavors of the dish you are consuming. In fact, you may be cognitively unaware of the char- acter of this new flavor because you are unable to identify it by name and, thus, as a new flavor category in your experience.

According to philosopher David Hume (1757), many of us do not have a sensitive enough palate to actually recognize new or unfamiliar flavors in familiar taste experiences. For those who do, it would seem that the test of a sensitive palate lies not with strong flavors but with faint ones. However, recent neurobiological research suggests that our responses to taste are not entirely dependent on the refinement of our sensory properties but, rather, on higher levels of linguistic processing (Grabenhorst, Rolls, & Bilderbeck, 2008). In other words, if you cannot describe it, it may be quite possible you are unable to taste it; our ability to skillfully use language thus improves our experience.

Logicians and philosophers in general take lan- guage very seriously because it is the best means for expressing our thoughts, to be understood by others, and to clarify ideas that are in need of clarification. Communicating in a language, however, is more com- plex than we recognize. As renowned philosopher John Searle observed, “Speaking a language is engag- ing in a rule-governed form of behavior” (Searle, 1969, p. 22). This means that whenever we talk or write, we are performing according to specific rules. Pauses in speech are represented by punctuation marks such as commas or periods. If we do not pause, the meaning of the same string of words could change its meaning completely. The same prin- ciple applies in writing. But although we are more conscious of making such pauses in speech, sometimes we overlook their importance in writing. A clever saying on a T-shirt illustrates this point, and it reads as follows:

Let’s eat Grandma.

Let’s eat, Grandma.

Commas save lives.

Georgios Kollidas/iStock/Thinkstock

Hume’s essay Of the Standard of Taste stated that taste depends on the refinement of sensory properties, but recent neurobiological research suggests that taste may actually be dependent on language.

har85668_01_c01_001-024.indd 18 4/9/15 11:20 AM

Section 1.6 Logic and Philosophy

Indeed, even what may seem like a meaningless little comma can dramatically change the meaning of a sentence. If we want to make sure others understand our written meaning, we need to be mindful of relevant punctuation, grammatical correctness, and proper spelling. If something is difficult to read because the grammar is faulty, punctuation is missing, or the words are misspelled, these obstacles will betray the writer’s meaning.

1.6 Logic and Philosophy By this point, you may have noticed that logic and philosophy are often mentioned together. There is good reason for this. Logic is not only an area of philosophy but also its bread and butter. It is important to understand the connection between these two fields because understanding the pursuit of philosophy will help clarify in your mind the value of logic in your life.

First, however, let us confront the elephant in the room. Some people have no idea what phi- losophers do. Others think that philosophers simply spend time thinking about things that have little practical use. The stereotypical image of a philosopher, for instance, is a bearded man asking himself: “If a tree falls in the forest and there is no one else to hear it, is there sound?” Your response to this may be: “Why should anyone care?” The fact is that many do, and not only bearded philosophers: Such a question is also critical to those who work at the boundaries of philosophy and science, as well as scientists who investigate the nature of sound, such as physicists, researchers in medicine and therapy, and those in the industry of sound technology.

Spatial views regarding sound, for example, have given rise to three theories: (a) sound is where there is a hearer, (b) sound is in the medium between the resonating sound and the hearer, and (c) sound is at the resonating object (Casati & Dokic, 2014). Accordingly, the tree in the forest question would have the following three corresponding answers: (a) no, if sound is where there is a hearer; (b) no, if sound is in the medium between the resonating sound and a hearer; and (c) yes, if sound is located in the resonating object such as a human ear. This seemingly impractical question, as it turns out, is not only quite interesting but also bears tangible results that lead to our better understanding of acoustics, hearing impairments, and sound technology. The best part is that the results affect us all. Many modern technologies arose from a “tree in the forest” examination.

Moral of the Story: The Importance of Language in Logic Clarity, precision, and correctness in language are not only important to the practical quest of communicating your ideas to others; they are fundamental to the practice of logical reasoning.

har85668_01_c01_001-024.indd 19 4/9/15 11:20 AM

Section 1.6 Logic and Philosophy

The Goal of Philosophy Now that the practical nature of philo- sophical inquiry has been demonstrated, we can move to a more fruitful exami- nation of what exactly philosophy is. In one view, philosophy is the activity of clarifying ideas. It is an activity because philosophy is not fundamentally a body of knowledge (as is history or biology, for example) but rather an activity. The goal of philosophical activity is to clarify ideas in the quest for truth.

How does one clarify ideas? By asking questions—especially “why?,” “what does that mean?,” and “what do you mean?” Philosophers have observed that asking such questions may be a natural human inclination. Consider any 2-year-old. As he or she begins to com-

mand the use of language, the child’s quest seems to be an attempt to understand the world by identifying what things are called. This may be annoying to some adults, but if we understand this activity as philosophical, the child’s goal is clear: Names are associated with meanings, and this process of making distinctions and comparisons of similarity is essentially the philosophical mechanism for learning (Sokolowski, 1998).

Once we name things, we can distinguish things that are similar because names help us sepa- rate things that appear alike. To a 2-year-old, a toy car and a toy truck may appear similar—both are vehicles, for example, and have four tires—but their different names reflect that there are also differences between them. So a 2-year-old will most likely go on to ask questions such as why a car is not the same as a truck until she grasps the fundamental differences between these two things. This is the truth-seeking nature of philosophy.

Philosophy and Logical Reasoning Since children’s natural learning state is a philosophical attitude, by the time we start elemen- tary school, we already have a few years of philosophical thinking under our belt. Unfortu- nately, the philosophical attitude is not always sustained beyond this point. Over time, we stop clarifying ideas because we might get discouraged from asking or we just get tired or complacent. We then begin to accept everything that we are told or shown by those around us, including what we watch on television or learn through social media. Once we stop filter- ing what we accept by means of questions, as we did when we were very small children, we become vulnerable to manipulation and deceit.

When we stop using questions to rationally discern among alternatives or to make judgments concerning disputed social problems, we begin to rely entirely on emotions or on past experi- ence as the basis for our decisions and judgments. As discussed earlier in the chapter, although


Children’s inquisitive nature personifies the act of being philosophical. Asking questions to clarify ideas or seek the truth is fundamental to engaging in philosophy.

har85668_01_c01_001-024.indd 20 4/9/15 11:20 AM

Summary and Resources

emotions are valid and worthwhile, they can also be unreliable or lead us to make rash deci- sions. This may be somewhat inconsequential if we are simply buying something on impulse at the mall. But if we make judgments based purely on fear or anger, then emotions have much more dire consequences, perhaps causing us to mistreat or discriminate against others.

Past experience can also be misleading. Consider Jay, a university student, who has done very well in his first four university courses. He has found the courses relatively easy and not very demanding, so he assumes that all university courses are easy. He is then surprised when he discovers that Introduction to Physics is a challenging course, when he should have rationally recognized that undertaking a university education is a challenging task. Asking himself questions about the past courses—subject matter, professor, and so on—may help Jay adjust his expectations.

Let us review two important points that we have discussed so far. First, philosophy is an activity of clarifying ideas. Second, the goal of philosophy is to seek truth about all phenom- ena in our experience. Logic provides us with an effective method for undertaking the task of philosophy and discovering truths. This view has thus remained mainstream in Western philosophy. When we think philosophically with regard to our mundane practical purposes, logic offers us the tools to break the habit of relying on our emotions, feelings, or our past experiences exclusively for making our decisions. Arriving at this recognition alone in your own case will be part and parcel of your journey, with this book as your guide.

Summary and Resources

Chapter Summary We have covered a lot of ground in this chapter. First we introduced the ideas of critical thinking and logic as tools that help us identify warranted judgments. In other words, if we have a belief, then logic helps us find an argument that warrants either our acceptance or rejection of this belief. By means of arguments, logic thus helps us clarify when our judg- ments are warranted and our beliefs are likely true. Second, we have presented a prelimi- nary understanding of the argument as a methodical defense of a position advanced in relation to a disputed issue. Arguments provide us with a structure that will help us discern fact from purely emotional appeal and identify sober judgment from wishful thinking. Third, we have defined philosophy as an activity of clarifying ideas. As such, it can be applied to ideas in every activity—for example, raising children, learning, tasks at work, cooking, mak- ing decisions—and to every discipline—for example, physics, mathematics, economics, biol- ogy, information systems, engineering, sociology, and so on.

Chapter 2 will introduce you to the argument, the principal tool of logic. Chapters 3 through 8 will teach you the applications of logical reasoning, and Chapter 9 will show you how the knowledge that you gained can be applied in your everyday life. Approach these chapters methodically: Do a first reading to get a general idea, then go back and focus on the details of each section of the chapters, always taking notes. Keep in mind that what you are learning is a method for thinking, so you cannot adopt it simply by reading. Practice what you are learning by doing the indicated exercises and activities.

The goal of this chapter has been to show you why logic is an indispensable tool in your life. (For some thoughts on how critical thinking and logic might apply to your life as a student,

har85668_01_c01_001-024.indd 21 4/9/15 11:20 AM

Summary and Resources

see Everyday Logic: Thinking Critically About Your Studies.) Over the course of this book, you will see how logical reasoning can help you make wiser choices. You will also find that the benefits extend beyond yourself, since by developing the habit of good reasoning you will also become more enlightened parents, better spouses, wiser voters, and more productive community members. There is a fundamental humanity in logical reasoning that brings people together rather than alienating them from one another. To achieve the habit of logical reasoning, this book will lead you in a methodical process in which each chapter will pro- vide you with an important element. Each component of this book is not only important but also necessary in learning the tools of logical reasoning.

Everyday Logic: Thinking Critically About Your Studies

You will likely find that there are multiple opportunities to apply and develop critical thinking skills in your life, but one of the most obvious opportunities at this juncture should be in your academic career. As you move forward in your studies, the decisions you make about partici- pation and study habits will affect your ability to succeed, so it is important that you approach them thoughtfully, carefully, and even critically. The goal of this feature box is to provide some insight into how good thinkers approach their studies and to offer some concrete methods for developing your own vision of academic success.

How have you approached school and education throughout your life? From a theoretical standpoint, all students know that the goal of college is to leave with skills that will allow them to pursue certain careers or, at the very least, help them survive and pursue their conception of a good life. Recall how interested you were in the world around you as a child or perhaps how excited you became when you acquired a new skill or discovered a new interest. These feelings and experiences are the essence of learning. Unfortunately, many people’s experience in formal education is not one of wonder and enjoyment, but one of boredom and tedium. The experience of the young child who found wonder and joy in discovering new things is often crushed in formal educational experiences.

So what can we do? How can we learn to love learning again and improve our thinking and study skills to make the most of our education? First you must identify and address your weak- nesses and bad habits. Do you aim only to pass a class, cramming for tests or doing the bare minimum on assignments, instead of steadily studying, reading, and taking notes for retention and understanding? Do you tune out when you think material is boring? Do you avoid asking questions because you are afraid of looking foolish or because it is easier to just accept ideas at face value? Do you allow certain activities to interfere with your studies?

It is impossible to change all of our bad habits instantaneously, but starting with just one or two can make a great difference. Here are some methods you can use to begin the journey toward becoming a better student and thinker:

• Avoid trying to multitask while studying, and perhaps even consider “fasting” from any media that tend to distract you or occupy inordinate amounts of your time. Tell oth- ers to turn off the TV, Xbox, computer, and so forth when they see you zoning out while engaging in these activities.

• Keep a journal and record urges that you have to fall into bad habits as well as goals you have for your intellectual and academic future. Make note of your triumphs over those negative urges. Review the journal regularly and reflect on how you are changing through what you are learning.


har85668_01_c01_001-024.indd 22 4/9/15 11:20 AM

Summary and Resources

• Surround yourself with people who will push you to higher levels of thinking and social action.

• Read slowly and repeatedly. Having to read a text more than once does not mean you are a poor reader. The philosopher Friedrich Nietzsche said that to read well, a human must become a cow. What does that mean? It means we need to ruminate, to chew and chew until we can swallow the meal. The process continues until we swallow and the food stays down, becoming nourishment to our minds.

• Take notes and practice writing skills when you get some free time. Try to learn a new grammar or usage rule every week. For example, do you know exactly when you should use a semicolon? If not, look it up right now. It is a really simple rule.

• Teach what you are learning to others. One of the best ways to determine if you have knowledge of something is if you can explain it and teach it to someone else.

• Recognize that this will take years of practice and will probably be slow going at first. Remember that small positive changes will add up to a whole new way of thinking and approaching life over time.

Finally, always remember that we are privileged to have the opportunity to pursue education. There are billions of people that will never have the opportunity to go to school or to provide that opportunity to their loved ones. Reformatting our perspective from one of frustration to one of gratitude can do a lot to change the way we approach education and learning. As you move forward this week, think about the following questions and how you might make changes in your own life that will lead to positive intellectual change.

• What is my view of education, and what experiences led me to that view? • What are my greatest strengths as a student? • What are my greatest weaknesses as a student? • How do I waste my time, and what might I do to utilize that time more effectively? • What is something I can do today that will help me become a better student and thinker? • What am I learning, and how has what I have learned changed who I am?

Everyday Logic: Thinking Critically About Your Studies (continued)

Critical Thinking Questions

1. What does the word critical in critical thinking mean? How would you explain criti- cal thinking to someone you know?

2. Do you have reasons for your most strongly held beliefs? To what extent are they based on emotions? Are they based in factual evidence and fair reasoning? Would other people find them convincing?

3. Are there beliefs that others hold that make you upset or angry? Why? How might you change your perspective in order not to react negatively when you hear contra- dictory beliefs?

4. Is it important to use language clearly? Why or why not? What are some steps that one can take to use language more clearly?

5. What is a logical argument? What role do you think logical argument could play in your life?

har85668_01_c01_001-024.indd 23 4/9/15 11:20 AM

Summary and Resources

Web Resources http://www.criticalthinking.org The Foundation for Critical Thinking maintains an extensive website regarding critical thinking and related scholarship.

http://herebedragonsmovie.com If you like to watch videos, Brian Dunning’s Here Be Dragons provides a nice introduction to some of critical thinking’s advantages and tools.

http://philosophy.hku.hk/think/critical/ct.php Hong Kong professors Joe Lau and Jonathan Chan sponsor open courseware on critical thinking at this website. This is a great place to look up specific concepts and ideas within critical thinking.

http://plato.stanford.edu The Stanford Encyclopedia of Philosophy is an excellent resource for any topics related to philosophy.

http://www.iep.utm.edu The Internet Encyclopedia of Philosophy is a peer-reviewed online academic resource of articles on philosophy.

Key Terms

critical thinking The activity of care- ful assessment and self-assessment that employs logical reasoning as the princi- pal basis for accepting beliefs or making judgments.

formal logic The abstract study of argu- ments, often using symbolic notation for analysis.

informal logic The study and description of reasoning in everyday life.

logic The study of arguments as tools for arriving at warranted judgments.

philosophy The activity of clarifying ideas with the goal of seeking truth.

rhetoric The art of persuasion.

har85668_01_c01_001-024.indd 24 4/9/15 11:20 AM


2The Argument


Learning Objectives After reading this chapter, you should be able to:

1. Articulate a clear definition of logical argument.

2. Name premise and conclusion indicators.

3. Extract an argument in the standard form from a speech or essay with the aid of paraphrasing.

4. Diagram an argument.

5. Identify two kinds of arguments—deductive and inductive.

6. Distinguish an argument from an explanation.

har85668_02_c02_025-058.indd 25 4/9/15 1:30 PM

Section 2.1 Arguments in Logic

Chapter 1 defined logic as the study of arguments that provides us with the tools for arriving at warranted judgments. The concept of argument is indeed central to this definition. In this chapter, then, our focus shall be entirely on defining arguments—what they are, how their component parts function, and how learning about arguments helps us lead better lives. Most especially, in this chapter we will introduce the standard argument form, which is the struc- ture that helps us identify arguments and distinguish good ones from bad ones.

2.1 Arguments in Logic Chapter 1 provisionally defined argument as a methodical defense of a position. We referred to this as the commonsense understanding of the way the word argument is employed in logic. The commonsense definition is very useful in helping us recognize a unique form of expression in ordinary human communication. It is part of the human condition to differ in opinion with another person and, in response, to attempt to change that person’s opinion. We may attempt, for example, to provide good reasons for seeing a particular movie or to show that our preferred kind of music is the best. Or we may try to show others that smoking or heavy drinking is harmful. As you will see, these are all arguments in the commonsense understanding of the term.

In Chapter 1 we also distinguished the commonsense understanding of argument from the meaning of argument in ordinary use. Arguments in ordinary use require an exchange between at least two people. As clarified in Chapter 1, commonsense arguments do not neces- sarily involve a dialogue and therefore do not involve an exchange. In fact, one could develop a methodical defense of a position—that is, a commonsense argument—in solitude, simply to examine what it would require to advocate for a particular position. In contrast, arguments, as understood in ordinary use, are characterized by verbal disputes between two or more people and often contain emotional outbursts. Commonsense arguments are not character- ized by emotional outbursts, since unbridled emotions present an enormous handicap for the development of a methodical defense of a position.

In logic an argument is a set of claims in which some, called the premises, serve as support for another claim, called the conclusion. The conclusion is the argument’s main claim. For the most part, this technical definition of argument is what we shall employ in the remainder of this book, though we may use the commonsense definition when talking about less technical examples. Table 2.1 should help clarify which meanings are acceptable within logic. Take a moment to review the table and fix these definitions in your mind.

Table 2.1: Comparing meanings for the term argument

Meaning in ordinary use Commonsense meaning Technical meaning in logic

A verbal quarrel or disagree- ment, often characterized by raised voices and flaring emotions.

The methodical and well- researched defense of a position or point of view advanced in relation to a disputed issue.

A set of claims in which some, called premises, serve as support for another claim, called the conclusion.

har85668_02_c02_025-058.indd 26 4/9/15 1:30 PM

Section 2.1 Arguments in Logic

Arguments in the technical sense are a primary way in which we can defend a position. Accordingly, we can find the structure of logical arguments in commonsense arguments all around us: in letters to the editor, social media, speeches, advertisements, sales pitches, pro- posals submitted for grant funds or bank loans, job applications, requests for a raise, commu- nications of values to children, marriage proposals, and so on. Arguments often provide the basis on which most of our decisions are made. We read or hear an argument, and if we are convinced by it, then we accept its conclusion. For example, consider the following argument:

“I’m just not a math person.” We hear this all the time from anyone who found high school math challenging. . . . In high school math at least, inborn talent is less important than hard work, preparation, and self-confidence. This is what high school math teachers, college professors, and private tutors have observed as the pattern of those who become good in high school math. They point out that in any given class, students fall in a wide range of levels of math preparation. This is not due to genetic predisposition. What is rarely observed is that some children come from households in which parents introduce them to math early on and encourage them to practice it. These students will imme- diately obtain perfect scores while the rest do not. As a result, the students without previous preparation in math immediately assume that those with perfect scores have a natural math talent, without knowing about the prepa- ration that these students had in their homes. In turn, the students who obtain perfect scores assume that they have a natural math talent given their scores relative to the rest of the class, so they are motivated to continue honing their math skills and, by doing this, they cement their top of the class standing. Thus, the belief that math ability cannot change becomes a self-fulfilling prophecy. (Kimball & Smith, 2013)

In this argument, the position defended by the authors is that the belief that math ability can- not change becomes a self-fulfilling prophecy. The authors support this claim with reasons that show good performance in math is not typically the result of a natural ability but of hav- ing a family support system for learning, a prior preparation in math from home, and continu- ous practice. It makes the case that it is hard work and preparation that lead to a person’s proficiency in math and other subjects, not genetic predisposition. This argument helps us recognize that we frequently accept oft-repeated information as fact without even question- ing the basis. As you can see, an argument such as this can provide a solid basis for our every- day decisions, such as encouraging our children to work hard and practice in the subjects they find most difficult or deciding to obtain a university degree with confidence later in life.

To understand the more technical definition of an argument as a set of premises that support a conclusion, consider the following presentation of the reasoning from the commonsense argument we have just examined.

Good performance in math is not due to genetics.

Good performance in math only requires preparation and continuous practice.

Students who do well initially assume they have natural talent and practice more.

har85668_02_c02_025-058.indd 27 4/9/15 1:30 PM

Section 2.1 Arguments in Logic

Students who do less well initially assume they do not have natural talent and practice less.

Therefore, believing that one’s math ability cannot change becomes a self- fulfilling prophecy.

Presenting the reasoning this way can do a great deal to clarify the argument and allow us to examine its central claims and reasoning. This is why the field of logic adopts the more techni- cal definition of argument for much of its work.

Regardless of what we think about math, an important contribution of this argument is that it makes the case that it is hard work and preparation that lead to our proficiency in math, and not the factor of genetic predisposition. Logic is much the same way. If you find some concepts difficult, don’t assume that you just lack talent and that you aren’t a “logic person.” With prac- tice and persistence, anyone can be a logic person.

On your way to becoming a logic person, it is important to remember that not everything that presents a point of view is an argument (see Table 2.2 for examples of arguments and nonar- guments). Consider that when one expresses a complaint, command, or explanation, one is indeed expressing a point of view. However, none of these amount to an argument.

Table 2.2: Is it an argument?

Argument Not an argument

Reprinted with permission from The Hill Times.

Why? This presents a defense of a position. But not all letters to the editor contain arguments.


Why not? This only reports a news story. It informs us of the role of the university but does not offer a defense of a position.


har85668_02_c02_025-058.indd 28 4/9/15 1:30 PM

Section 2.1 Arguments in Logic

Argument Not an argument

Greg Gibson/Associated Press

Why? This is a photo of former president Bill Clin- ton making a speech, in which he defends his posi- tion that the facts are different than those reported by the media. Not all speeches contain arguments, only those that defend a position.

©MIKE SEGAR/Reuters/Corbis

Why not? This is a debate between two presidential candidates. Although each candidate may present various arguments, the debate as a whole is not an argument. It is not a defense of a position; it is an exchange between two people on various subjects.

Emmanuel Dunand/AFP/Getty Images

Why? This ad makes a claim and offers a reason for why viewers should take notice.

©James Lawrence/Transtock/Corbis

Why not? This ad has no words, so it makes no specific claim. Even if we try to interpret it to make a claim, no defense is offered.

To help us properly identify logical arguments, we need clear criteria for what a logical argu- ment is. Let us start unpacking what is involved in arguments by addressing their smallest element: the claim.

Claims A claim is an assertion that something is or is not the case. Claims take the form of declara- tive sentences. It is important to note that each premise or conclusion consists of one single claim. In other words, each premise or conclusion consists of one single declarative sentence.

Claims can be either true or false. This means that if what is asserted is actually the case, then the claim is true. If the claim does not correspond to what is actually the case, then the claim is false. For example, the claim “milk is in the refrigerator” predicates that the subject of the

Table 2.2: Is it an argument? (continued)

har85668_02_c02_025-058.indd 29 4/9/15 1:31 PM

Section 2.1 Arguments in Logic

claim, milk, is in the refrigerator. If this claim corresponds to the facts (if the refrigerator con- tains milk), then this claim is true. If it does not correspond to the facts (if the refrigerator does not contain milk), then the claim is false.

Not all claims, however, can be easily checked for truth or falsity. For exam- ple, the truth of the claim “Jacob has the best wife in the world” cannot be settled easily, even if Jacob is the one asserting this claim (“I have the best wife in the world”). In order to under- stand what he could possibly mean by “best wife in the world,” we would have to propose the criteria for what makes a good wife in the first place, and as if this were not challenging enough, we would then have to establish a method or procedure to make comparisons among good wives. Of course, Jacob could merely mean “I like being mar- ried to my wife,” in which case he is not stating a claim about his wife being the

best in the world but merely stating a feeling. It is not uncommon to hear people state things that sound like claims but are actually just expressions of preference or affection, and distin- guishing between these is often challenging because we are not always clear in the way we employ language. Nonetheless, it is important to note that we often make claims from a par- ticular point of view, and these claims are different from factual claims. Claims that advance a point of view, such as the example of Jacob’s wife—and especially claims about morality and ethicality—are indeed more challenging to settle as true or false than factual claims, such as “The speed limit here is 55.”

The important point is that both kinds of claims—the factual claim and the point-of-view claim—assert that something is or is not the case, affirm or deny a particular predicate of a subject, and can be either true or false. The following sentences are examples of claims that meet these criteria.

• There is a full moon tonight. • Pecans are better than peanuts. • All flights to Paris are full. • BMWs are expensive to maintain. • Lola is my sister.

The following are not claims:

• Is it raining? Why? Because questions are not, and cannot be, assertions that some- thing is the case.

• Oh, to be in Paris in the springtime! Why? Because this expresses a sentiment but does not state that anything might be true or false.

• Buy a BMW! Why? Because a command is not an assertion that something is the case.

Image Source Pink/Image Source/Thinkstock

What factual claims can you make about this image?

har85668_02_c02_025-058.indd 30 4/9/15 1:31 PM

Section 2.1 Arguments in Logic

We often intend to advance claims in ways that do not present our claims clearly and properly— for example, by means of rhetorical questions, vague expressions of affection, and commands or metaphors that demand interpretation. But it is important to recognize that intention is not sufficient when communicating with others. In order for our intended claims to be identified as claims, they should meet the three criteria previously mentioned.

Claims are sometimes called propositions. We will use the terms claims and propositions inter- changeably in this book. In this chapter we will stick to the word claim, but in subsequent chapters, we will move to the more formal terminology of propositions.

The Standard Argument Form In informal logic the main method for identifying, constructing, or examining arguments is to extract what we hear or read as arguments and put this in what is known as the standard argument form. It consists of claims, some of which are called premises and one of which is called the conclusion. In the standard argument form, premises are listed first, each on a separate line, with the conclusion on the line after the last premise. There are various meth- ods for displaying standard form. Some methods number the premises; others separate the conclusion with a line. We will generally use the following method, prefacing the conclusion with the word therefore:

Premise Premise Therefore, Conclusion

The number of premises can be as few as one and as many as needed. We must approach either extreme with caution given that, on the one hand, a single premise can offer only very limited support for the conclusion, and on the other hand, many premises risk error or confu- sion. However, there are certain kinds of arguments that, because of their formal structure, may contain only a limited number of premises.

In the standard argument form, each premise or conclusion should be only one sentence long, and premises and conclusions should be stated as clearly and briefly as possible. Accordingly, we must avoid premises or conclusions that have multiple sentences or single sentences with multiple claims. The following example shows what not to do:

I live in Boston, and I like clam chowder. My family also lives in Boston. They also like clam chowder. My friends live in Boston. They all like clam chowder, too. Therefore, everyone I know in Boston likes clam chowder.

If you want to make more than one claim about the same subject, then you can break your declarative sentences into several sentences that each contain only one claim. The clam chow- der argument can then be rewritten as follows:

I live in Boston. I like clam chowder. My family lives in Boston. My family likes clam chowder.

har85668_02_c02_025-058.indd 31 4/9/15 1:31 PM

Section 2.1 Arguments in Logic

My friends live in Boston. My friends like clam chowder. Therefore, everyone I know in Boston likes clam chowder.

The relationship between premises and the conclusion is that of inference—the process of drawing a claim (the conclusion) from the reasons offered in the premises. The act of reason- ing from the premises serves as the glue connecting the premises with the conclusion.

Practice Problems 2.1

Determine whether the following sentences are claims (propositions) or nonclaims (nonpropositions).

1. Moby Dick is a great novel.

2. Computers have made our lives easier.

3. If we go to the movies, we will need to drive the minivan.

4. Do you want to drive the minivan to the movies?

5. Drive the minivan.

6. Either I am a human or I am a dog.

7. Michael Jordan was a great football player.

8. Was it time for you to leave?

9. Private property is a right of every American.

10. Universalized health care is communism.

11. Don’t you dare vote for universalized health care.

12. Nietzsche collapsed in a square upon seeing a man beat a horse.

13. Hooray!

14. Those who reject equality seek tyranny.

15. How many feet are in a mile?

16. If you cannot understand the truth value of a claim, then it is not a claim.

17. Something is a claim if and only if it has a truth value.

18. Treat your boss with respect.

19. Men are much less likely to have osteoporosis than women are.

20. Why are women less likely to have heart attacks?

21. Do as we say.

22. I believe that you should do as your parents say.

23. Socrates is mortal. (continued)

har85668_02_c02_025-058.indd 32 4/9/15 1:31 PM

Section 2.2 Putting Arguments in the Standard Form

24. Why did Freud hold such strange beliefs about parent–child relationships?

25. A democracy exists if and only if its citizens participate in autonomous elections.

26. Do your best.

27. The unexamined life is not worth living.

28. Ayn Rand believed that selfishness was a virtue.

29. Is selfishness a virtue?

30. What people love is not the object of desire, but desire itself.

31. Hey!

32. Those who cannot support themselves should not be supported by taxpayer dollars.

33. Particle and wave behavior are properties of light.

34. Why do we feed so many pounds of plants to animals each year?

35. Go and give your brother a kiss.

36. Because the mind conditions reality, it is impossible to know the thing as such.

37. The library at the local university has more than 300,000 books.

38. Does the nature of reality consist of an ultimately creative impulse?

39. You are taking a quiz.

40. Are you taking a quiz?

Practice Problems 2.1 (continued)

2.2 Putting Arguments in the Standard Form Presenting arguments in the standard argument form is crucial because it provides us with a dispassionate method that will allow us to find out whether the argument is good, regardless of how we feel about the subject matter. The first step is to identify the fundamental argument being presented.

At first it might seem a bit daunting to identify an argument, because arguments typically do not come neatly presented in the standard argument form. Instead, they may come in confus- ing and unclear language, much like this statement by Special Prosecutor Francis Schmitz of Wisconsin regarding Governor Scott Walker:

Governor Walker was not a target of the investigation. At no time has he been served with a subpoena. . . . While these documents outlined the prosecutor’s legal theory, they did not establish the existence of a crime; rather, they were arguments in support of further investigation to determine if criminal charges against any person or entity are warranted. (Crocker, 2014, para. 7 & 10)

har85668_02_c02_025-058.indd 33 4/9/15 1:31 PM

Section 2.2 Putting Arguments in the Standard Form

This was a position presented in regard to the investigation of an alleged illegal campaign finance coordination during the 2011–2012 recall elections (Stein, 2014). Does it claim a vin- dication of Walker? Or does it suggest that there may be sufficient evidence to make Walker a central figure in the investigation? How would you even begin to make heads or tails of such a confusing argument? Do not despair. The remainder of this section will show you exactly what to look for in order to make sense of the most complicated argument. With a little prac- tice, you will be able to do this without much effort.

Find the Conclusion First Although the conclusion is last in the standard form, the conclusion is the first thing to find because the conclu- sion is the main claim in an argument. The other claims—the premises—are present for the sole purpose of support- ing the conclusion. Accordingly, if you are able to find the conclusion, then you should be able to find the premises.

The good news is that language is not only a means for expressing ideas; it also offers a road map for the ideas presented. Chapter 1 underscored the fundamental importance of clear, pre- cise, and correct language in logical reasoning. When used properly, lan- guage also offers structures and direc- tions for communicating meaning, thus facilitating our understanding of what others are saying. One punctua- tion mark—the question mark—tells us that we are confronting a question. A different punctuation mark—the parentheses—tells us that we are being given relevant information but only as an aside or afterthought to the main point; if removed, the parenthetical information would not alter the main point. In the case of arguments, some words serve as signposts identifying conclusions. Take the following example of an argument in the standard argument form:

All men are mortal. Socrates is a man. Therefore, Socrates is mortal.

The word therefore indicates that the sentence is a conclusion. In fact, the word therefore is the standard conclusion indicator we will use when constructing arguments in the stan- dard argument form. However, there are other conclusion indicators that are used in ordinary arguments, including:

• Consequently . . . • So . . . • Hence . . . • Thus . . .

Xtock Images/iStock/Thinkstock

Punctuation, parentheses, and conclusion indicators all serve as signposts to assist us when deconstructing an argument. They provide important clues about where to find the conclusion as well as supporting claims.

har85668_02_c02_025-058.indd 34 4/9/15 1:31 PM

Section 2.2 Putting Arguments in the Standard Form

• Wherefore . . . • As a result . . . • It follows that . . . • For these reasons . . . • We may conclude that . . .

When a conclusion indicator is present, it can help identify the conclusion in an argument. Unfortunately, many arguments do not come with conclusion indicators. In such cases start by trying to identify the main point. If you can clearly identify a single main point, then that is likely to be the conclusion. But sometimes you will have to look at a passage closely to find the conclusion. Suppose you encounter the following argument:

Don’t you know that driving without a seat belt is dangerous? Statistics show that you are 10 times more likely to be injured in an accident if you are not wearing one. Besides, in our state you can get fined $100 if you are caught not wearing one. You ought to wear one even if you are driving a short distance.

Arguments are often longer and more complicated than this one, but let us work with this simple case before trying more complicated examples. You know that the first thing you need to do is to look for the conclusion. The problem is that the author of the argument does not use a conclusion indicator. Now what? Nothing to worry about. Just remember that the con- clusion is the main claim, so the thing to look for is what the author may be trying to defend. Although the first sentence is stated as a question—remember, punctuation marks give us important clues—the author seems to intend to assert that driving without a seat belt is dan- gerous. In fact, the second sentence offers evidence in support of this claim. On the other hand, the third sentence seems to be important, yet it does not speak to driving without a seat belt being dangerous, only expensive. In the final sentence, we find a claim that is supported by all the others. Because of this, the final sentence presents the conclusion.

Now, it so happens that in this case, the conclusion is at the end of this short argument, but keep in mind that conclusions can be found in various places in essays, such as the beginning or sometimes in the middle. Now that you have identified your first piece of the puzzle, we have this:

Premise 1: ? Premise 2: ? Premise 3: ? Therefore, you ought to wear a seat belt whenever you drive.

You might have noticed that the conclusion does not appear as it did in the essay. The origi- nal sentence is “You ought to wear one even if you are driving a short distance.” Why did we modify it? Once again, clarity is of the essence in logical reasoning. Conclusions should make the subject clear, so the pronoun one was replaced with the actual subject to which the author is referring: seat belt. In addition, the predicate “even if you are driving a short distance” was rewritten to reflect the more inclusive point that the author seems to be making: that you should wear a seat belt whenever you drive.

har85668_02_c02_025-058.indd 35 4/9/15 1:31 PM

Section 2.2 Putting Arguments in the Standard Form

This modification of language, known as paraphrasing, is part of the construction of argu- ments in the standard argument form. The act of extracting an argument from a longer piece to its fundamental claims in the standard argument form necessarily involves paraphrasing the original language to the clearest and most precise form possible. This concept will be addressed in greater detail later in this section.

Find the Premises Next After identifying the conclusion, the next thing to do is look for the reasons the author offers in defense of his or her position. These are the premises. As with conclusions, there are prem- ise indicators that serve as signposts that reasons are being offered for the main claim or conclusion. Some examples of premise indicators are:

• Since . . . • For . . . • Given that . . . • Because . . . • As . . . • Owing to . . . • Seeing that . . . • May be inferred from . . .

To practice identifying premises, let us return to our seat belt example:

Don’t you know that driving without a seat belt is dangerous? Statistics show that you are 10 times more likely to be injured in an accident if you are not wearing one. Besides, in our state you can get fined $100 if you are caught not wearing one. You ought to wear one even if you are driving a short distance.

Notice again that this argument starts with a question: “Don’t you know that driving without a seat belt is danger- ous?” The author is not really asking whether you know that driving with- out a seat belt is dangerous. Rather, the author seems to be asking a rhe- torical question—a question that does not actually demand an answer—to assert that driving without a seat belt is dangerous. You should avoid asking rhetorical questions in the essays that you write, because the outcome can be highly uncertain. The success of a rhe- torical question depends on the reader or listener first understanding the hid- den meaning behind the rhetorical question and then correctly articulat- ing the answer you have in mind. This does not always work.


Much like a map will get you from point A to point B, putting an argument into the standard

“Order a similar paper and get 20% discount on your first order with us Use the following coupon “GET20”