Logic: American Association of State Colleges and Universities and Subsequent Rights Restrictions

Sequenced. Precise. Elegant. Clear. Hurleys A Concise Introduction to logic, 11th Edition How to set up an Origami Crane Make your own origami crane utilize these instructions and the perforated sheet of paper include in your mass. 1. Start with a squ ar go of paper, colored side up. conclude in half and open. Then fold in half the other way. 2. Turn the paper over to the white side. show up the paper in half, crease well and open, and then fold again in the other direction. 3. Using the creases you have made, bring the top 3 corners of the position down to the bottom corner.Flatten model. The iconic red crane on the cover of this radical edition of Hurleys, A Concise Introduction to Logic symbolizes the qualities that call for it the roughly(prenominal) successful logic text on the market. We have chosen origami to symbolize this texts c arful sequencing, precision, elegance, and clarity. About the Cover 4. Fold top angulate flaps into the center and unfold. 5. Fold top of model downwards, crease well and unfold. 6. Open the uppermost flap of the model, bringing it upwards and pressing the sides of the model inwards at the same conviction. Flatten down, creasing well.Couple an icon steeped in tradition with a clean, modern design, and you ordain quickly get a sense of the qualities that make this new edition of Hurley the best yet. Along with instructions, each new text includes a sheet of red paper so that you behind bring the cover to life. This physical exertion serves as a metaphor for the process of learn logic. It is challenging, withdraws practice, but can be fun. Ideas for other ways to create your own origami can be tack at www. origami-resource-center. com. 7. Turn model over and repeat Steps 4-6 on the other side. . Fold top flaps into the center. 9. Repeat on other side. 10. Fold both legs of 11. Inside Reverse Fold the legs model up, crease along the creases very well, then you just made. unfold. Finished Crane. 12. Inside Reverse Fold angiotensin converting enzyme side to make a head, then fold down the wings. Source www. origami-fun. com Copy refine 2010 Cengage in dression. tout ensemble Rights Reserved. whitethorn non be copied, scanned, or duplicated, in integral or in parcel. referable to electronic experts, more or less 3rd gear society subject whitethorn be conquer from the eBook and/or eChapter(s). column critical review has deemed that whatsoever stifled substance does non materially act the overall learning experience. Cengage knowledge militia the right to sequester extra fill at both snip if accomp eaching rights restrictions admit it. A C O N C I S E I N T R O D U C T I O N TO Logic copyright 2010 Cengage scholarship. in all Rights Reserved. May non be copied, scanned, or duplicated, in unscathed or in part. overdue to electronic rights, few third party inwardness whitethorn be smo in that respectd from the eBook and/or eChapter(s). newspaper colu mn review has deemed that each stifled field of study does non materially act the overall learning experience. Cengage breeding reserves the right to mutilate additional message at any conviction if concomitant rights restrictions take in it. Copyright 2010 Cengage schooling. al one Rights Reserved. May not be copied, scanned, or duplicated, in solely or in part. Due to electronic rights, some third party content whitethorn be stamp down from the eBook and/or eChapter(s). editorial review has deemed that any hold in content does not materially affect the overall learning experience.Cengage information reserves the right to remove additional content at any clipping if subsequent rights restrictions require it. A C O N C I S E I N T R O D U C T I O N TO Logic ELEVENTH EDITION PATRICK J. HURLEY University of San Diego Australia Brazil Japan Korea Mexico Singapore Spain United Kingdom United States Copyright 2010 Cengage tuition. All Rights Reserved. May not b e copied, scanned, or duplicated, in self-coloured or in part. Due to electronic rights, some third party content may be stifled from the eBook and/or eChapter(s). pillar review has deemed that any moderate content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any meter if subsequent rights restrictions require it. This is an electronic version of the print textbook. Due to electronic rights restrictions, some third party content may be suppressed. Editorial review has deemed that any suppressed content does not materially affect the overall learning experience.The publishing ho implement reserves the right to remove content from this title at any time if subsequent rights restrictions require it. For valuable information on pricing, previous editions, changes to electric current editions, and alternate formats, please visit www. cengage. com/highered to search by ISBN, author, title, or keyword for materials in your beas of occupy. Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in entirely or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. A Concise Introduction to Logic, El heretoforeth Edition Patrick J. Hurley Publisher Clark Baxter older Sponsoring Editor Joann Kozyrev Development Editor Florence Kilgo Assistant Editor Nathan Gamache Editorial Assistant Michaela Henry Media Editor Diane Akerman Marketing Manager Mark T.Haynes Marketing Coordinator Josh Hendrick Marketing Communications Manager Laura Localio Content Project Manager Alison Eigel Zade Senior Art Director Jennifer Wahi Print Buyer capital of Minnesotaa Van g Production Service Elm Street Publishing Services Internal designer Yvo Riezebos Cover designer Jeff whammy of CMB Design Partners Cover image Courtesy of Getty Images Red origami crane on white table (image number 85592979) Compositor Integra Softw atomic number 18 Services Pvt. Ltd. 2012, 2008, 2006 Wadsworth, Cengage Learning ALL RIGHTS RESERVED.No part of this run short covered by the copyright herein may be reproduced, transmitted, stored, or employ in any form or by any means graphic, electronic, or mechanical, including but not limited to photocopying, recording, scanning, digitizing, taping, Web distribution, information ne tworks, or information storage and retrieval systems, except as permitted under Section 107 or 108 of the 1976 United States Copyright Act, without the prior written per exception of the publisher.For product information and technology assistance, jot us at Cengage Learning Customer & Sales Support, 1-800-354-9706 For permission to use material fro m this text or product, submit all requests online at www. cengage. com/permissions. Further permissions questions can be emailed to email defend com. Library of relation Control Number 2010924757 Student Edition ISBN-13 978-0-8400-3417-5 ISBN-10 0-8400-3417-2 Wadsworth 20 Channel Center Street Boston, MA 02210 USA Cengage Learning is a leading provider of customized learning solutions with o? e locations around the globe, including Singapore, the United Kingdom, Australia, Mexico, Brazil, and Japan. Locate your local o? ce at international. cengage. com/region Cengage Learning products ar re booned in Canada by Nelson Education, Ltd. For your strain and learning solutions, visit www. cengage. com. Purchase any of our products at your local college store or at our preferred online store www. cengagebrain. com. Printed in the United States of the States 1 2 3 4 5 6 7 14 13 12 11 10 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in w hole or in part.Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. To All of the instructors, past and present, who have taught logic from this book. It is wrong always, everywhere, and for anyone, to believe anything upon insufficient evidence. W. K. Clifford slide fastener can be more important than the art of formal conclude jibe to genuine logic. Gottfried Wilhelm Leibniz Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learn ing experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Brief Contents Preface xiii PART IINFORMAL LOGIC 1 2 3 Basic Concepts 1 Language Meaning and De? ition 78 Informal Fallacies 119 PART IIFORMAL LOGIC 4 5 6 7 8 Categorical Propositions 197 Categorical Syllogisms 259 Propositional Logic 310 Natural Deduction in Propositional Logic 380 Predicate Logic 442 PART IIIINDUCTIVE LOGIC 9 10 11 12 13 14 Analogy and Legal and Moral modestness 509 Causality and Mills Methods 529 Prob cleverness 554 Statistical Reasoning 571 Hypothetical/Scienti? c Reasoning 593 Science and Superstition 615 Appendix Logic and Graduate-Level Admissions Tests 644 Answers to Selected Exercises 655 Glossary/Index 697 vi Copyright 2010 Cengage Learning. All Rights Reserved.May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eCha pter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Contents Preface xiii PART I? INFORMAL LOGIC 1 Basic Concepts workout 1. 1 7 1 1 14 33 1. 1 Arguments, Premises, and Conclusions 1. 2 Recognizing Arguments recitation 1. 2 25 1. 3 Deduction and innovation proceeding 1. 40 1. 4 Validity, honor, Soundness, Strength, Cogency 44 purpose 1. 4 53 1. 5 Argument Forms Proving Invalidity action 1. 5 63 57 1. 6 Extended Arguments action 1. 6 70 64 2 Language Meaning and De? nition 2. 1 Varieties of Meaning EXERCISE 2. 1 83 78 78 88 2. 2 The Intension and Extension of Terms EXERCISE 2. 2 92 2. 3 De? nitions and Their Purposes EXERCISE 2. 3 99 93 2. 4 De? nitional Techniques EXERCISE 2. 4 108 102 111 2. 5 Criteria for Lexical De? nitions EXERCISE 2. 5 115 vii Copyright 2010 Cengage Learning. A ll Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part.Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 3 Informal Fallacies 3. 1 Fallacies in General EXERCISE 3. 1 121 119 122 138 119 3. 2 Fallacies of Relevance EXERCISE 3. 2 133 3. 3 Fallacies of untoughened Induction EXERCISE 3. 3 149 3. 4 Fallacies of Presumption, Ambiguity, and Grammatical Analogy 156 EXERCISE 3. 4 170 . 5 Fallacies in routine Language EXERCISE 3. 5 185 178 PART II? FORMAL LOGIC 4 Categorical Propositions 197 4. 1 The Components of Categorical Propositions 197 EXERCISE 4. 1 200 4. 2 Quality, Quantity, and Distribution EXERCISE 4. 2 204 200 4. 3 Venn Diagrams and the Modern Square of Opposition 205 EXERCISE 4. 3 216 4. 4 Conversion, Obversion, and Contraposition EXERCISE 4. 4 225 217 4. 5 The Traditional Square of Opposition EXERCISE 4. 5 234 227 4. 6 Venn Diagrams and the Traditional Stand speckle 239 EXERCISE 4. 6 245 4. 7 Translating Ordinary Language Statements into Categorical Form 246 EXERCISE 4. 254 viii Contents Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 5 Categorical Syllogisms 259 5. 1 Standard Form, Mood, and mental image 259 EXERCISE 5. 1 264 5. 2 Venn Diagrams EXERCISE 5. 277 266 280 288 292 5. 3 Rules and Fallacies EXERCISE 5. 3 286 5. 4 Reducing the Number of Terms EXERCISE 5. 4 291 5. 5 Ordinary Language Arguments EXERCISE 5. 5 294 5. 6 Enthymemes 295 EXERCISE 5. 6 297 5. 7 Sorites 301 EXERCISE 5. 7 304 6 Propositional Logic EXERCISE 6. 1 319 310 6. 1 Symbols and interlingual rendition 310 6. 2 Truth Functions EXERCISE 6. 2 332 323 6. 3 Truth Tables for Propositions 335 EXERCISE 6. 3 341 6. 4 Truth Tables for Arguments EXERCISE 6. 4 347 344 6. 5 Indirect Truth Tables 350 EXERCISE 6. 5 358 6. 6 Argument Forms and Fallacies EXERCISE 6. 6 371 360 Contents ixCopyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 7 Natural Deduc tion in Propositional Logic 380 7. 1 Rules of Implication I 380 EXERCISE 7. 1 386 7. 2 Rules of Implication II 391 EXERCISE 7. 396 7. 3 Rules of Replacement I 401 EXERCISE 7. 3 407 7. 4 Rules of Replacement II EXERCISE 7. 4 419 414 7. 5 qualified Proof EXERCISE 7. 5 430 427 7. 6 Indirect Proof EXERCISE 7. 6 436 432 438 7. 7 Proving Logical Truths EXERCISE 7. 7 440 8 Predicate Logic 442 8. 1 Symbols and commentary 442 EXERCISE 8. 1 449 8. 2 Using the Rules of Inference EXERCISE 8. 2 460 451 8. 3 Change of Quanti? er Rule EXERCISE 8. 3 467 464 468 8. 4 Conditional and Indirect Proof EXERCISE 8. 4 472 8. 5 Proving Invalidity EXERCISE 8. 5 479 474 481 8. 6 Relational Predicates and Overlapping Quanti? ers EXERCISE 8. 6 489 . 7 identicalness 492 EXERCISE 8. 7 501 x Contents Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChap ter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Part III INDUCTIVE LOGIC 9 Analogy and Legal and Moral Reasoning 509 9. 1 Analogical Reasoning 9. Legal Reasoning 9. 3 Moral Reasoning EXERCISE 9 520 509 512 516 10 Causality and Mills Methods 10. 2 Mills Five Methods 531 10. 3 Mills Methods and Science EXERCISE 10 546 529 529 10. 1 Cause and Necessary and Sufficient Conditions 540 11 Probability 554 11. 1 Theories of Probability 11. 2 The Probability Calculus EXERCISE 11 567 554 557 12 Statistical Reasoning 571 12. 1 Evaluating Statistics 571 12. 2 Samples 572 576 12. 3 The Meaning of Average 12. 4 Dispersion 578 12. 5 Graphs and Pictograms 12. 6 Percentages 586 EXERCISE 12 588 583 13 Hypothetical/Scienti? c Reasoning 593 13. The Hypothetical Method 593 13. 2 Hypothetical Reasoning Four Ex amples from Science 596 Contents xi Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 13. 3 The Proof of Hypotheses EXERCISE 13 607 02 13. 4 The probationary Acceptance of Hypotheses 604 14 Science and Superstition 14. 2 Evidentiary Support 14. 3 Objectivity 14. 4 Integrity EXERCISE 14 615 615 14. 1 Distinguishing in the midst of Science and Superstition 616 621 625 630 631 14. 5 Concluding Remarks Appendix Logic and Graduate-Level Admissions Tests 644 Answers to Selected Exercises Glossary/Index 697 655 xii Contents Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Preface The most immediate benefit derived from the study of logic is the skill needed to construct rifle arguments of ones own and to evaluate the arguments of others. In accomplishing this goal, logic instills a sensitivity for the formal component in language, a thorough command of which is native to clear, e? ective, and meaningful communication.On a broader scale, by focusing attention on the requisite for reasons or evidence to support our views, logic provides a fundamental exculpation against the prejudiced and uncivilized attitudes that threaten the foundations of our democratic society. Finally, through its attention to inconsistency as a fatal ? aw in any theory or point of view, logic proves a useful device in disclosing ill-conceived policies in the political sphere and, ultimately, in distinguishing the rational from the irrational, the sane from the insane. This book is written with the look at of securing these bene? s. Every Book Has a Story When I ? rst began teaching introductory logic many old age ago, I selected a textbook that was widely used and highly regarded. Yet, my students often had a hard time understanding it. The book tended to be overly wordy and the main points were often lost amid a mess of detail. Also, I found that much of the books content was only peripherally related to the central concepts of logic. Using this book provided the happy and unanticipated provide that my students always came to class so they could hear me explain the textbook.But by and by I tired of doing this, I decided to write a textbook of my own that would lot the de? ciencies of the one I had been using. Speci? cally, my goal was to write a book in which the main points were always presented up front so students could not possibly miss them, the prose was clear and uncomplicated, and excess verbiage and peripheral subject matter was avoided. To accomplish these and other related goals, I incorporated the following(a) pedagogical devices Relevant and cutting-edge examples were used extensively throughout the book. Key toll were introduced in bold face type and de? ed in the glossary/index. Central concepts were illustrated in graphic boxes. Numerous exercisestoday there are over 2,600were included to perfect student skills. Many exercises were drawn from real(a)-life sources such as textbooks, newspapers, and magazines. Typically every third exercise was answered in the back of the book so students could check their work. xiii Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplica ted, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Chapters were organized so that earlier sections provided the foundation for later ones. Later sections could be skipped by instructors opting to do so. Important rules and tables were printed on the inside covers for frame access. In its ? rst edition, the book was so well received that plans were quickly begun for a second edition.With the completion of that and later editions, the book grew to incorporate many new features Venn diagrams for syllogisms were presented in a novel and more e? ective way using color to identify the relevant areas. Dialogue exercises were included to depict the commission of fallacies i n real life. Predicate logic was extended to include relational predicates and identity. The Eminent Logicians feature was introduced to elevate the human member it presented the lives of historically prominent logicians. Truth Trees and Critical sentiment and Writing were written as supplements. Learning Logic, a multimedia program that includes an additional 2,000 exercises and that practically teaches the course by itself, was included in the package. A serial of videos dealing with topics that students ? nd di? cult, including the concept of validity, indirect truth tables, and natural deduction, were o? ered with the last edition. I am convinced that with each successive edition the book has become a more e? ective teaching tool. I am also convinced that the current, eleventh edition, is the best and most accurate one to date. bran-new To This Edition Five new biographical vignettes of prominent logicians are introduced.The new logicians include Ruth Barcan Marcus, Al ice Ambrose, Ada Byron (Countess of Lovelace), Willard Van Orman Quine, and Saul Kripke. Six new talk exercises are introduced to help a? rm the relevance of formal logic to real-life. They can be found in Sections 5. 6, 6. 4, 6. 6, 7. 3, 7. 4, and 8. 2. The end-of-chapter summaries now appear in bullet format to make them more useful for student review. Many new and improved exercises and examples appear throughout the book. In Section 1. 4, the link amidst inductive reasoning and the principle of the uniformity of nature is explained.Cogent inductive arguments are those that accord with this principle, bit weak ones violate it. Such violations are always accompanied by an element of surprise. xiv Preface Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed cont ent does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. The connection between the Boolean Standpoint and the Aristotelian standpoint is explained more completely. The existential delusion as it occurs in immediate inferences is explained in greater detail. All inferences that commit this fallacy have a universal present and a particular mop up. The meaning of universal and particular are extended to cover avowals that are given as false. A new exercise set is introduced in Section 4. 5 that involves testing immediate inferences for soundness. An improved de? nition of the main operator of a compound argumentation is given. A new subsection is introduced in Section 6. 5 giving preliminary instruction on how to work backward from the truth values of the truthful propositions to the truth values of the operators. A new exercise set provides practi ce with this technique. Section 7. 1 has been rewritten, emphasizing the strategy of trying to ? nd the end point in the premises. Margin of error in Chapter 12 is now explained in terms of level of expectation. A more informative table illustrates this change. A complete identify of all improvements is given at the beginning of the Instructors Manual.Note to the Student Imagine that you are interviewing for a job. The person across the desk asks about your strengths, and you reply that you are energetic, en indeediastic, and willing to work long hours. Also, you are creative and innovative, and you have good leadership skills. Then the interviewer asks about your weaknesses. You hadnt anticipated this question, but after a moments thought you reply that your reasoning skills have never been very good. The interviewer quickly responds that this weakness could create big problems. Why is that? you ask. Because reasoning skills are essential to good judgment. And without good jud gment your creativity will lead to projects that make no sense. Your leadership skills will direct our other employees in circles. Your frenzy will undermine everything we have accomplished up until now. And your working long hours will make things even worse. But dont you think there is some position in your company that is right for me? you ask. The interviewer thinks for a moment and then replies, We have a competitor on the other side of town. I hear they are hiring right now. Why dont you apply with them? The point of this little dialogue is that good reasoning skills are essential to doing anything right. The note person uses reasoning skills in writing a report or preparing a presentation the scientist uses them in designing an experiment or clinical trial, the plane section manager uses them in maximizing worker e? ciency, the lawyer uses them in composing an argument to a judge or jury. And thats where logic comes in. The primary(prenominal) purpose of logic is to br eak in good reasoning skills. In fact, logic is so important that when the liberal arts program of studies was formulated ? fteen hundred days Preface v Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. ago, logic was selected as one of the original seven liberal arts. Logic outrides to this day a central component of a college or university education.From a more pragmatic angle, logic is important to earning a good score on any of the several tests required for admission to graduate professional schoolsthe LSAT, GMAT, MCAT, and so on. Obviously, the designers of these tests re cognize that the ability to reason logically is a prerequisite to success in these ? elds. The appendix in the back of the book contains sample questions and cues on answering them. Also, logic is a useful tool in relieving what has come to be called math anxiety. For whatever reason, countless students today are terri? ed of any form of reasoning that involves vellicate symbols.If you happen to be one of these students, you should ? nd it relatively easy to master the use of logical symbols, and your newly found comfort with these symbols will carry over into the other, more di? cult ? elds. To improve your performance in logic, I strongly urge you to take full advantage of a multimedia program called Learning Logic. This is an interactive tutorial that teaches the essentials of this textbook in a very user-friendly way. However, your computer must be equipped with loudspeakers or headphones, because the audio component is essential.Learning Logic is available both on CD and onlin e at the Logic CourseMate site. If the CD version or a passcode for the website did not come with your textbook, it can be purchased one at a time through your campus bookstore if your instructor has ordered it. You can also order it directly at www. cengagebrain. com. In addition to Learning Logic, an eBook and other quizzes and self-study material are available on the Logic CourseMate site. Also available online through the Logic CourseMate site are brief video lectures on key topics. The videos include pointers on how to work the pertinent exercises in the textbook.They cover topics such as the concept of validity, conversion, obversion, and contraposition, indirect truth tables, and natural deduction. If, as you work through the content of this book, you catch a subject that you have trouble understanding, one of these videos may solve the problem. superfluously, a set of audio summaries for each chapter in the book is available. These are knowing so that you can download th em onto your iPod, mp3 player, or computer and listen to them before taking a test. Because pro? ciency in logic involves developing a kill, it helps to work through the practice problems in Learning Logic and the exercises in the textbook more than once. This will help you see that good reasoning (and bad reasoning, too) follows reliable patterns whose identi? cation is crucial to success in logic. As you progress, I think you will ? nd that learning logic can be lots of fun, and working with the online resources should enhance your overall learning experience. Note to the Instructor With this eleventh edition, Learning Logic is available both on CD and online. The CD comes free ifordered with a new book, or it can be ordered separately at www. engagebrain. com. Online, Learning Logic it is available through the Logic CourseMate site, a password protected website (www. cengage. com/sso). This website o? ers the bene? t of being able to check a students time on task, that is, how m uch time the student has spent using a particular supplement. Critical Thinking and Writing and Truthtrees are available free on the website, and they can also be selected as modules in a custom version of the textbook. The videos, which cover topics students often have trouble with, are also available on Logic CourseMate.This edition also features Aplia, one of the Cengage Learning CourseMaster digital solutions. Aplia established a name for itself in the ? eld of economics, where it o? ers interactive online homework xvi Preface Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience.Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. assignments with continuous feedback to students. Providing automatic grading, Aplia increases student effort and keeps students accountable for course material while adding no additional paperwork to the instructors workload, leaving instructors with more time to prepare lectures and work with students. As Aplia expands its o? erings to include additional subjects, it has won general acclaim from thousands of instructors across numerous disciplines. Now, Aplia o? ers its signature bene? s to logic students and instructors with a program speci? cally designed to enhance student engagement. The Aplia assignments build on the exercises in this textbook, and they conform to the language, style, and structure of the book. Let me now turn to alternate ways of approaching the textbook. In general, the material in each chapter is arranged so that authorized later sections can be skipped without a? ecting subsequent chapters. For example, those wishing a brief treatment of natural deducti on in both propositional and predicate logic may motive to skip the last three sections of Chapter 7 and the last four (or even ? e) sections of Chapter 8. Chapter 2 can be skipped altogether, although some may want to cover the ? rst section of that chapter as an introduction to Chapter 3. Finally, Chapters 9 through 14 depend only slightly on earlier chapters, so these can be treated in any order one chooses. However, Chapter 14 does depend in part on Chapter 13. Type of Course Traditional logic course Recommended material Chapter 1 Chapter 3 Chapter 4 Chapter 5 Chapter 6 Sections 7. 17. 4 Informal logic course, critical reasoning course Chapter 1 Chapter 2 Chapter 3 Chapter 4 Sections 5. 15. Sections 5. 55. 6 Sections 6. 16. 4 Section 6. 6 Chapter 9 Chapter 12 Chapter 13 Chapter 14 Writing appurtenance Section 5. 4 Section 5. 7 Section 6. 5 Chapter 10 Chapter 11 Course emphasizing modern formal logic Chapter 1 Sections 4. 14. 3 Section 4. 7 Sections 6. 16. 5 Chapter 7 Chapter 8 Truth Tree Supplement Optional material Chapter 2 Sections 7. 57. 7 Chapters 914 Chapter 3 Sections 4. 44. 6 Sections 5. 15. 2 Section 5. 7 Section 6. 6 Preface xvii Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part.Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Acknowledgements For their reviews and suggestions leading to this eleventh edition I want to thank the following Kevin Berry Scott Calef Gabriel Camacho Loren Cannon Victor Cosculluela Thompson Faller Thomas J.Frost Paul Gass Alexander Hall Courtney Hammond Merle Harton Anthony Hanson Ron Jackson William Jamison Sandra Johanson Richard Jones Russel Jones William Lawh ead Stephen Leach Keane Lundt Erik Meade Ian MacKinnon Allyson Mount Seyed Mousavian Madeline Muntersbjorn Herminia Reyes Frank Ryan Eric Saidel Stephanie Semler Janet Simpson Aeon Skoble Joshua metalworker Paula Smithka Krys Sulewski Brian Tapia William Vanderburgh Mark Vopat David Weise Shannon Grace Werre Katherine D.Witzig Stephen Wykstra Ohio University Ohio Wesleyan University El Paso conjunction College Humboldt State University Polk State College University of Portland Biola University/Long Beach metropolis College Coppin State University Clayton State University Cuyamaca College Edward Waters College West valley College Clayton State University University of Alaska Anchorage Green River Community College Howard University University of Oklahoma University of Mississippi UTPA Massachusetts College of Liberal Arts Southern Illinois UniversityEdwardsville The University of Akron Keene State College University of Alberta University of Toledo San Diego State University Kent St ate University George capital letter University Radford University Su? olk County Community College Bridgewater State College Central Michigan University University of Southern Mississippi Edmonds Community College Foothill College Wichita State University Youngstown State University Gonzaga University Edmonds Community College Southwestern Illinois College Calvin College Of course any errors or omissions that may remain are the result of my own oversight. xviii Preface Copyright 2010 Cengage Learning. All Rights Reserved.May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Those who have contributed reviews and suggestions leading to the ten previous editions, and to whom I express my continued thanks, are the following James T. Anderson, University of San Diego Carol Anthony, Villanova University Joseph Asike, Howard University Harriet E.Baber, University of San Diego Kent Baldner, Western Michigan University James Baley, bloody shame Washington College Jerome Balmuth, Colgate University Victor Balowitz, State University of New York, College at Buffalo Ida Baltikauskas, Century College Gary Baran, Los Angeles City College Robert Barnard, University of Mississippi Gregory Bassham, Kings College Thora Bayer, Xavier University of Louisiana David Behan, Agnes Scott College conjuration Bender, Ohio University, Athens James O. Bennett, University of Tennessee, Knoxville Victoria Berdon, IUPU capital of Ohio Robert Berman, Xavier University of Louisana Joseph Bessie, Normandale Community College John R. 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Due to ele ctronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. University Robert Urekew, University of Louisville William Uzgalis, Oregon State University Thomas H. Warren, Solano Colleg Andrew J.Waskey, Dalton State University Roy Weatherford, University of South Florida Chris Weigand, Our Lady of the Lake University David Weinburger, Stockton State College Paul Weirich, University of Missouri, Columbia Robert Wengert, University of Illinois, Urbana/Champaign Gerald Joseph Williams, Seton Hall University Frank Wilson, Bucknell University W. Kent Wilson, University of Illinois, Chicago Stephen Wykstra, Calvin College Marie Zaccaria, Georgia Perimeter College Jeffrey Zents, University of Texas Finally, it has been a pl easure working with philosophy editor Joann Kozyrev, development editor Florence Kilgo, project manager Alison Eigel Zade, project editors Emily Winders and Amanda Hellenthal, and editorial assistant Michaela Henry. Preface blackjack Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affe ct the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 1 Basic Concepts 1. 1 1. 2 1. 3 1. 4 1. 5 1. Arguments, Premises, and Conclusions Recognizing Arguments Deduction and Induction Validity, Truth, Soundness, Strength, Cogency Argument Forms Proving Invalidity Extended Arguments 1. 1 Arguments, Premises, and Conclusions Logic may be de? ned as the organized body of knowledge, or science, that evaluates arguments. All of us converge arguments in our day-to-day experience. We read them in books and newspapers, hear them on television, and formulate them when communicating with friends and associates. The aim of logic is to develop a system of regularitys and principles that we may use as criteria for evaluating the arguments of others and as guides in constructing arguments of our own.Among the bene? ts to be expected from the study of logic is an increase in con? dence that we are making sense when we criticize the arguments of others and when we get along arguments of our own. An argument, in its most basic form, is a group of statements, one or more of which (the premises) are claimed to provide support for, or reasons to believe, one of the others (the conclusion). All arguments may be placed in one of two basic groups those in which the premises really do support the conclusion and those in which they do not, even though they are claimed to. The former are said to be good arguments (at least to that extent), the latter bad arguments.The purpose of logic, as the science that evaluates arguments, is thus to develop methods and techniques that allow us to distinguish good arguments from bad. As is apparent from the given definition, the term argument has a very specific meaning in logic. It does not mean, for example, a mere verbal ? ght, as one mighthave with ones parent, spouse, or friend. Let us examine the features of this de? nition in Additional r esources are available on the Logic CourseMate website. 1 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 1 greater detail. First of all, an argument is a group of statements. A statement is a sentence that is either true or falsein other words, typically a declarative sentence or a sentence component that could stand as a declarative sentence. The following sentences are statements Chocolate truffles are loaded with calories. Melatonin helps relieve jet lag. Political candidates always tell the complete truth.No wives ever cheat on their husbands. Tiger Woods plays golf and Ma ria Sharapova plays tennis. The first two statements are true, the second two false. The last one expresses two statements, both of which are true. Truth and falsity are called the two possible truth values of a statement. Thus, the truth value of the ? rst two statements is true, the truth value of the second two is false, and the truth value of the last statement, as well as that of its components, is true. Unlike statements, many sentences cannot be said to be either true or false. Questions, proposals, suggestions, commands, and exclamations ordinarily cannot, and so are not usually classi? ed as statements.The following sentences are not statements Where is Khartoum? Lets go to a movie tonight. I suggest you get contact lenses. Turn off the TV right now. Fantastic (question) (proposal) (suggestion) (command) (exclamation) The statements that make up an argument are divided into one or more premises and one and only one conclusion. The premises are the statements that set forth the reasons or evidence, and the conclusion is the statement that the evidence is claimed to support or imply. In other words, the conclusion is the statement that is claimed to follow from the premises. Here is an example of an argument All film stars are celebrities. Halle Berry is a film star.Therefore, Halle Berry is a celebrity. The ? rst two statements are the premises the third is the conclusion. (The claim that the premises support or imply the conclusion is indicated by the word therefore. ) In this argument the premises really do support the conclusion, and so the argument is a good one. But consider this argument Some film stars are men. Cameron Diaz is a film star. Therefore, Cameron Diaz is a man. In this argument the premises do not support the conclusion, even though they are claimed to, and so the argument is not a good one. One of the most important tasks in the analysis of arguments is being able to distinguish premises from conclusions.If what is thought to be a conclusion is really a premise, and vice versa, the subsequent analysis cannot possibly be correct. Manyarguments 2 Chapter 1 Basic Concepts Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. contain indicator words that provide clues in identifying premises and conclusion.Some typical conclusion indicators are therefore wherefore thus consequently we may infer accordingly we may conclude it must be that for this reason so entails that hence it follows that implies that as a result 1 Whenever a statement follows one of these indicators, it can usually be identi? ed as the conclusi on. By process of elimination the other statements in the argument are the premises. Example Tortured prisoners will say anything just to relieve the pain. Consequently, torture is not a reliable method of interrogation. The conclusion of this argument is Torture is not a reliable method of interrogation, and the premise is Tortured prisoners will say anything just to relieve the pain. Premises Claimed evidence Conclusion What is claimed to follow from the evidenceIf an argument does not contain a conclusion indicator, it may contain a premise indicator. Some typical premise indicators are since as indicated by because for in that may be inferred from as given that seeing that for the reason that in as much as owing to Any statement following one of these indicators can usually be identi? ed as a premise. Example Expectant mothers should never use recreational drugs, since the use of these drugs can jeopardize the development of the fetus. The premise of this argument is The use of these drugs can jeopardize the development of the fetus, and the conclusion is Expectant mothers should never use recreational drugs. In reviewing the list of indicators, note that for this reason is a conclusion indicator, whereas for the reason that is a premise indicator. For this reason (except Section 1. 1 Arguments, Premises, and Conclusions 3 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 1 hen followed by a colon) means for the reason (premise) that was just given, so what follows is the conclusion. On the other hand, for the reason that announces that a premise is ab out to be stated. Sometimes a angiotensin-converting enzyme indicator can be used to identify more than one premise. carry on the following argument It is vitally important that wilderness areas be preserved, for wilderness provides essential habitat for wildlife, including endangered species, and it is a natural retreat from the stress of day-by-day life. The premise indicator for goes with both Wilderness provides essential habitat for wildlife, including endangered species, and It is a natural retreat from the stress of daily life. These are the premises. By method of elimination, It is vitally important that wilderness areas be preserved is the conclusion. Some arguments contain no indicators. With these, the reader/listener must ask such questions as What single statement is claimed (implicitly) to follow from the others? What is the arguer trying to prove? What is the main point in the passage? The answers to these questions should point to the conclusion. Example The space program deserves increased expenditures in the years ahead. Not only does the national defense depend on it, but the program will more than pay for itself in terms of expert spinoffs.Furthermore, at current funding levels the program cannot fulfill its anticipated potential. The conclusion of this argument is the ? rst statement, and all of the other statements are premises. The argument illustrates the pattern found in most arguments that lack indicator words the intended conclusion is stated ? rst, and the remaining statements are then o? ered in support of this ? rst statement. When the argument is restructured according to logical principles, however, the conclusion is always listed after the premises P1 P2 P3 C The national defense is dependent on the space program. The space program will more than pay for itself in terms of technological spinoffs.At current funding levels the space program cannot fulfill its anticipated potential. The space program deserves increased expendi tures in the years ahead. When restructuring arguments such as this, one should remain as close as possible to the original version, while at the same time attending to the requirement that premises and conclusion be complete sentences that are meaningful in the order in which they are listed. Note that the ? rst two premises are included within the scope of a single sentence in the original argument. For the purposes of this chapter, compound arrangements of statements in which the various components are all claimed to be true will be considered as separate statements.Passages that contain arguments sometimes contain statements that are neither premises nor conclusions. Only statements that are actually intended to support the conclusion should be included in the list of premises. If, for example, a statement 4 Chapter 1 Basic Concepts Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. erves merely to introduce the general topic, or merely makes a acquittance comment, it should not be interpreted as part of the argument. Examples The claim is often made that malpractice lawsuits drive up the cost of health care. But if such suits were outlawed or severely restricted, then patients would have no means of recovery for injuries caused by negligent doctors. Hence, the availability of malpractice litigation should be maintained intact. Massive federal deficits push up interest rates for everyone. Servicing the debt gobbles up a huge portion of the federal budget, which lowers our standard of living. And big deficits also weaken the value of the dollar. For thes e reasons, Congress must make a determined effort to cut overall spending and raise taxes.Politicians who ignore this reality imperil the future of the nation. 1 In the ? rst argument, the opening statement serves merely to introduce the topic, so it is not part of the argument. The premise is the second statement, and the conclusion is the last statement. In the second argument, the ? nal statement merely makes a passing comment, so it is not part of the argument. The premises are the ? rst three statements, and the statement following for these reasons is the conclusion. Closely related to the concepts of argument and statement are those of inference and proposition. An inference, in the narrow sense of the term, is the reasoning process expressed by an argument.In the broad sense of the term, inference is used interchangeably with argument. Analogously, a proposition, in the narrow sense, is the meaning or information content of a statement. For the purposes of this book, howeve r, proposition and statement are used interchangeably. Note on the History of Logic The person who is generally attribute as the father of logic is the ancient Greek philosopher Aristotle (384322 b. c. ). Aristotles predecessors had been interested in the art of constructing persuasive arguments and in techniques for refuting the arguments of others, but it was Aristotle who ? rst devised systematic criteria for analyzing and evaluating arguments.Aristotles heading accomplishment is called syllogistic logic, a kind of logic in which the fundamental elements are terms, and arguments are evaluated as good or bad depending on how the terms are arranged in the argument. Chapters 4 and 5 of this textbook are devoted mainly to syllogistic logic. But Aristotle also deserves credit for originating modal logic, a kind of logic that involves such concepts as possibility, necessity, belief, and doubt. In addition, Aristotle catalogued several informal fallacies, a topic treated in Chapter 3 of this book. After Aristotles death, other Greek philosopher, Chrysippus (280206 b. c. ), one of the founders of the Stoic school, developed a logic in which the fundamental elements were whole propositions.Chrysippus treated every proposition as either true or false and developed rules for determining the truth or falsity of compound propositions from the truth or falsity of their components. In the course of doing so, he pose the foundation for the truth functional interpretation of the logical connectives presented in Chapter 6 of this book and introduced the notion of natural deduction, treated in Chapter 7. Section 1. 1 Arguments, Premises, and Conclusions 5 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).Editorial review has deemed that any suppressed content does not materially affect the overall learni ng experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 1 For thirteen hundred years after the death of Chrysippus, relatively little creative work was done in logic. The physician Galen (a. d. 129ca. 199) developed the theory of the compound categorical syllogism, but for the most part philosophers con? ned themselves to writing commentaries on the works of Aristotle and Chrysippus. Boethius (ca. 480524) is a noteworthy example. The ? rst major logician of the Middle Ages was Peter Abelard (10791142). Abelard reconstructed and re? ed the logic of Aristotle and Chrysippus as communicated by Boethius, and he originated a theory of universals that traced the universal character of general terms to concepts in the mind rather than to natures existing outside the mind, as Aristotle had held. In addition, Abelard distinguished arguments that arevalid because of their form from those that are valid because o f their content, but he held that only formal validity is the perfect or conclusive variety. The present text