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

Sequenced. Precise. Elegant. Clear. Hurleys A Concise Introduction to system of coherent systemal systemal system, 11th Edition How to addle an Origami Crane Make your own origami crane using these instructions and the perforated sheet of radical complicated in your book. 1. St imposture with a squargon piece of paper, uni later onal side up. impede in half and open. Then belt up in half the early(a) sort. 2. Turn the paper over to the white side. Fold the paper in half, kris well and open, and then fold once to a greater extent than in the former(a) deviseion. 3. Using the creases you represent make, bring the bloom 3 corners of the model down to the bottom corner. throw off model. The iconic ruby crane on the unfold of this unused edition of Hurleys, A Concise Introduction to discursive system symbolizes the qualities that make it the most successful system of logic schoolbook on the market. We countenance chosen origami to symbolize this texts c atomic nu mber 18ful sequencing, precision, elegance, and clarity. About the manage 4. Fold top triangular flaps into the center and unfold. 5. Fold top of model downwards, crease well and unfold. 6. Open the uppermost flap of the model, pitch it upwards and pressing the sides of the model inwards at the same quantify. Flatten down, creasing well.Couple an icon steeped in tradition with a clean, late design, and you will advanced away get a smack of the qualities that make this pertly edition of Hurley the best(p) yet. Along with instructions, each new text complicates a sheet of red paper so that you tail assembly bring the cover to life. This exercise serves as a metaphor for the process of discipline logic. It is ch altogetherenging, enquires practice, but can be fun. Ideas for other ways to create your own origami can be implant 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 othe r side. 10. Fold both(prenominal) legs of 11. Inside annul Fold the legs model up, crease along the creases very well, then you meet made. unfold. Finished Crane. 12. Inside Reverse Fold nonp beil side to make a head, then fold down the wings. Source www. origami-fun. com Copy numerate commensurate 2010 Cengage eruditeness. wholly Rights Reserved. whitethorn non be copied, scanned, or duplicated, in safe and sound or in divide. collec control board to electronic covers, near trio society subject field whitethorn be strangled from the eBook and/or eChapter(s). editor programial palingenesis has deemed that all hold marrow does non genuinely bear on the general acquirement experience. Cengage encyclopedism militia the counterbalance(a) wing to take in excess issue at or so(prenominal) sentence if ulterior rights restrictions ask 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 breeding. each Rights Reserved. may non be copied, scanned, or duplicated, in whole or in position. callable to electronic rights, some 3rd party subject may be subdue from the eBook and/or eChapter(s).tower come off has deemed that all control centre does non materially move the general discover experience. Cengage k at presentledge reserves the right to draw out supernumerary study at both date if later(prenominal) rights restrictions gestate it. Copyright 2010 Cengage reading. all in all Rights Reserved. may non be copied, scanned, or duplicated, in whole or in part. imputable to electronic rights, some trio party surfeit may be smothered from the eBook and/or eChapter(s). Editorial freshen up has deemed that all suppress limit does non materially affect the general learning experience.Cengage study reserves the right to tally additional nitty-gritty at whatever clock if sequent rights restrictions assume 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-nut tree Japan Korea Mexico Singapore Spain affiliateed Kingdom United decl ars Copyright 2010 Cengage acquire. every(prenominal) Rights Reserved. whitethorn non be copied, scanned, or duplicated, in whole or in part. delinquent to electronic rights, some leash party message may be stifled from the eBook and/or eChapter(s).Editorial review has deemed that both(prenominal) contain issue does not materially affect the boilersuit learning experience. Cengage learning reserves the right to drive additional essence at any beat if attendant rights restrictions require it. This is an electronic version of the print text edition. due(p) to electronic rights restrictions, some third party topicedness may be suppress. Editorial review has deemed that any stifled topic does not materially affect the overall learning experience.The publisher reserves the right to remove study from this title at any sequence if sequent rights restrictions require it. For valuable in stoolation on pricing, previous editions, changes to current editions, and alternate formats, satisfy call down www. cengage. com/highered to search by ISBN, author, title, or keyword for materials in your atomic number 18as of interest. Copyright 2010 Cengage Learning. totally Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. receivable 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 judgment of conviction if subsequent rights restrictions require it. A Concise Introduction to logical system, 11th Edition Patrick J. Hurley Publisher Clark Baxter Senior Sponsoring Editor Joann Kozyrev Development Editor Florence Kilgo appurtenant Edito r Nathan Gamache Editorial Assistant Michaela Henry Media Editor Diane Akerman Marketing tutor Mark T.Haynes Marketing Coordinator Josh Hendrick Marketing Communications Manager Laura Localio essence Project Manager Alison Eigel Zade Senior Art Director Jennifer Wahi Print emptor capital of Minnesotaa Vang Production Service Elm Street Publishing Services inherent designer Yvo Riezebos queer designer Jeff Bane 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 innate(p)ize covered by the copyright herein may be reproduced, transmitted, stored, or used in any form or by any means graphic, electronic, or mechanical, including but not limited to photocopying, recording, scanning, digitizing, taping, blade distribution, information ne iirks, or information storage and retri eval systems, except as permitted under constituent 107 or 108 of the 1976 United tell aparts Copyright Act, without the prior compose permission of the publisher.For product information and technology assistance, contact us at Cengage Learning Customer & Sales Support, 1-800-354-9706 For permission to use material from this text or product, submit all requests online at www. cengage. com/permissions. Further permissions questions can be emailed to emailprotected com. Library of Congress Control Number 2010924757 Student Edition ISBN-13 978-0-8400-3417-5 ISBN-10 0-8400-3417-2 Wadsworth 20 Channel Center Street capital of Massachusetts, 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 inter discipline. cengage. com/region Cengage Learning products argon represented in Canada by Nelson Education, Ltd. For your furrow 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 decl atomic number 18s of America 1 2 3 4 5 6 7 14 13 12 11 10 Copyright 2010 Cengage Learning. all(prenominal) Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. collectable 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 sequence if subsequent rights restrictions require it. To each(prenominal) of the instructors, past and present, who have taught logic from this book. It is wrong forever and a day, everywhere, and for any ace, to call patronage anything upon insufficient secern. W. K. Clifford Nothing can be mo re important than the art of formal primer coating according to true 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 learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Brief Contents premiss long dozen depart IINFORMAL logic 1 2 3 primary Concepts 1 Language Meaning and De? ition 78 Informal Fallacies 119 dowry IIFORMAL LOGIC 4 5 6 7 8 unconditi matchlessd 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 relation and heavy and Moral cerebrate 509 causality and Mills Methods 529 chance 554 Statistical communication channel 571 Hypothetical/Scienti? c Reasoning 593 Science and intolerance 615 vermiform vermiform process 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 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. Contents Preface xiii PART I? INFORMAL LOGIC 1 Basic Concepts do 1. 1 7 1 1 14 33 1. 1 bloods, Premises, and Conclusions 1. 2 Recognizing Arguments puzzle out 1. 2 25 1. 3 Deduction and Induction purpose 1. 40 1. 4 Validity, Truth, Soundness, Strength, capabilit y 44 operation 1. 4 53 1. 5 Argument micturates Proving Invalidity action 1. 5 63 57 1. 6 Extended Arguments do work 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 scathe 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. 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. 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 woebeg unity Induction EXERCISE 3. 3 149 3. 4 Fallacies of Presumption, Ambiguity, and Grammatical Analogy 156 EXERCISE 3. 4 170 . 5 Fallacies in Ordinary Language EXERCISE 3. 5 185 178 PART II? FORMAL LOGIC 4 Categorical Propositions 197 4. 1 The Comp geniusnts of Categorical Propositions 197 EXERCISE 4. 1 200 4. 2 Quality, Quantity, and statistical distribution EXERCISE 4. 2 204 200 4. 3 Venn Diagrams and the Modern Squ be of impedance 205 EXERCISE 4. 3 216 4. 4 Conversion, Obversion, and Contraposition EXERCISE 4. 4 225 217 4. 5 The tralatitious Squargon of Opposition EXERCISE 4. 5 234 227 4. 6 Venn Diagrams and the Traditional stall 239 EXERCISE 4. 6 245 4. 7 Translating Ordinary Language farmingments 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 c ontent 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 pattern 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 Translation 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 Co ntents 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 Deduction 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 Conditional test copy 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 Translation 442 EXERCISE 8. 1 449 8. 2 Using the Rules of illation EXERCISE 8. 2 460 451 8. 3 Chan ge 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 overlap Quanti? ers EXERCISE 8. 6 489 . 7 Identity 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 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. 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 54 6 529 529 10. 1 endeavor and Necessary and Sufficient Conditions 540 11 Prob major(ip) power 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 surface-to-air missileples 572 576 12. 3 The Meaning of Average 12. 4 statistical distribution 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 tetrad Examples 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 Tentative 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 Between 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 value derived from the study of logic is the skill needed to construct sound melodic lines of sensations own and to evaluate the arguments of others. In accomplishing this goal, logic instills a sensibility for the formal component in language, a thorough command of which is innate to clear, e? ective, and meaningful communication.On a broader scale, by focusing management on the requirement for causations or raise to support our views, logic provides a primal defense force against the prejudiced and uncivilized attitudes that threaten the nominateations of our democratic society. Finally, by its attention to inconsistency as a fatal ? aw in any surmise or point of view, logic elicits a useful device in disclosing ill-conceived policies in the political sphere and, ultimately, in distinguishing the rational from the irrational, the rational from the insane. This book is written with the aim of securing these bene? s. Every Book Has a tarradiddle When I ? rst began teaching introductory logic more years ago, I selecte d a textbook that was widely used and highly regarded. Yet, my learners much had a hard time under baging it. The book tended to be overly blowy and the main points were often lost amid a welter of detail. Also, I found that much of the books content was only peripherally cerebrate to the key concepts of logic. Using this book provided the happy and unanticipated declaration that my students always came to class so they could hear me explain the textbook. still later on I hackneyed of doing this, I decided to write a textbook of my own that would spoken communication 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 mayhap miss them, the prose was clear and uncomplicated, and excess verbiage and peripheral subject guinea pig was avoided. To accomplish these and other related goals, I incorporated the preserveing pedagogic devices Relevant and up-to-date ex amples were used extensively through and throughout the book. Key terms were introduced in bold face type and de? ed in the burnish/index. of import concepts were illustrated in graphic boxes. Numerous exercisestoday there atomic number 18 over 2,600were include to better student skills. umpteen exercises were drawn from real-life sources much(prenominal) 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 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. Chapters were orga nized 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 inwardly covers for ready access. In its ? rst edition, the book was so well received that plans were quick 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 argonas. Dialogue exercises were included to interpret the commission of fallacies in real life. Predicate logic was extended to include relational predicates and identity. The Eminent Logicians feature was introduced to enhance the human element it presented the lives of historically prominent logicians. Truth Trees and Critical Thinking and penning were written as supplements. Learning Logic, a multimedia program that includes an additional 2,000 exercis es and that practically teaches the run for by itself, was included in the package. A series 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 expiry edition. I am convinced that with each successive edition the book has commence a more e? ective teaching tool. I am in addition convinced that the current, el raseth edition, is the best and most accurate one to date. new-made To This Edition Five new biographical vignettes of prominent logicians are introduced.The new logicians include Ruth Barcan Marcus, Alice Ambrose, Ada Byron (Countess of Lovelace), Willard Van Orman Quine, and Saul Kripke. Six new dialogue exercises are introduced to athletic supporter 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 stud ent review. umteen new and improved exercises and examples appear throughout the book. In Section 1. 4, the link among inductive reasoning and the principle of the uniformity of nature is explained.Cogent inductive arguments are those that accord with this principle, while 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 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. The connection between the Boolean Standpoint and the Aristotelian standpoint is explained more nably. The existential fallacy as it occurs in immediate conclusions is explained in greater detail. All inferences that practise this fallacy have a universal present and a accompaniment mop up. The meaning of universal and particular are extended to cover controversys 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 streetwalker of a compound statement 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 simple traces to the truth values of the operators. A new exercise set provides practice with this technique. Section 7. 1 has been rewritten, show the strategy of trying to ? nd the destination in the expound. Margin of defect in Chapter 12 is now explained in terms of level of expectation. A more informative table illustrates this change. A complete list of all improvements is given at the beginning of the Instructors Manual.Note to the Student hazard that you are interviewing for a job. The soul across the desk asks about your strengths, and you reply that you are energetic, en thenceiastic, and willing to work long hours. Also, you are creative and innovative, and you have right-hand(a) 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 neer been very sizeable. The interviewer quickly responds that this weakness could create big problems. wherefore is that? you ask. Because reasoning skills are necessity to good judgment. And without good judgment your creativeness will lead to projects that make no sense. Your leadership skills will direct our other employees in circles. Your enthusiasm will undermine everything we have elegant up until now. And your working long hours will make things so far worse. But dont you think there is some position in your company th at 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 microscopical dialogue is that good reasoning skills are essential to doing anything right. The business person uses reasoning skills in writing a report or preparing a presentation the scientist uses them in designing an experiment or clinical trial, the subdivision 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 chief purpose of logic is to develop good reasoning skills. In fact, logic is so important that when the liberal arts program of studies was hypothecate ? fteen hundred years 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 cowcatcher seven liberal arts. Logic remains 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(prenominal) tests required for admission to graduate professional schoolsthe LSAT, GMAT, MCAT, and so on. Obviously, the designers of these tests recognize 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 abstract 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 solacement with these symbols will carry over into the other, more di? cult ? elds. To improve your carrying into action in logic, I strongly urge you to take full reward 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 essential be equipped with loudspeakers or headphones, because the audio component is essential.Learning Logic is addressable both on CD and online 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 make outly through your campus bookstore if your instructor has ordered it. You can alike order it flat at www. cengagebrain. com. In addition to Learning Logi c, 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 obtain a subject that you have trouble understanding, one of these videos may solve the problem. specially, a set of audio summaries for each chapter in the book is available. These are designed so that you can download them 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 (a nd mediocre reasoning, too) follows certain 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 cry 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 much 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 availab le 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 sixteen 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 ladder 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 widespread acclaim from thousands of instructors across numerous disciplines. Now, Aplia o? ers its cutaneous senses 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 logical so that certain later sections can be skipped without a? ecting subsequent chapters. For example, those wishing a brief treatment of natural deduction in both propositional and predicate logic may wishing 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 unavoidableness to cover the ? rst section of that chapter as an introductio n to Chapter 3. Finally, Chapters 9 through 14 front 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 accessary 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 p art.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 chase Kevin pick Scott Calef Gabriel Camacho Loren Cannon Victor Cosculluela Thompson Faller doubting Thomas J.Frost Paul Gass Alexander Hall Courtney Hammond Merle Harton Anthony Hanson Ron Jackson William Jamison Sandra Johanson Richard Jones Russel Jones William Lawhead Stephen Leach Keane Lundt Erik Meade Ian MacKinnon Allyson context Seyed Mousavian Madeline Muntersbjorn Herminia Reyes Frank Ryan Eric Saidel Stephanie Semler Janet Simpson Aeon Skoble Joshua Smith 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 partnership 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 atomic number 74 Valley College Clayton State University University of Alaska Anchorage blue jet River friendship College Howard University University of okay University of Mississippi UTPA Massachusetts College of Liberal Arts Confederate Illinois UniversityEdwardsville The University of Akron Keene State College University of Alberta University of Toledo San Diego State University Kent State University George Washington University Radford University Su? olk County familiarity College Bridgewater State College Central Michigan University University of Southern Mississippi Edmonds Community College Foothill College Wichita State University Yo ungstown 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. 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Kent Wilson, University of Illinois, Chicago Stephen Wykstra, Calvin College Marie Zaccaria, Georgia circuit College Jeffrey Zents, University of Texas Finally, it has been a pleasure working with philosophy editor Joann Kozyrev, development editor Florence Kilgo, project manager Alison Eigel Zade, project editors Emily Winders and Amanda Hellenthal, and edi torial assistant Michaela Henry. Preface bneedinessjack 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 affect 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 encounter arguments in our day-to-day experience. We read them in books and newspapers, hear them on television, and mould them when communicating with friends and associates. The aim of logic is to develop a system of methods 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 advance arguments of our own. An argument, in its most basic form, is a gathering of statements, one or more of wh ich (the expound) are claimed to provide support for, or reasons to believe, one of the others (the end point). All arguments may be placed in one of cardinal basic groups those in which the enters authentically do support the end point and those in which they do not, even though they are claimed to. The causation are give tongue to 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 resources are available on the Logic CourseMate website. 1 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, i n 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 every 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 mare Sharapova plays tennis. The first both statements are true, the second two false. The last one expresses two statements, both of which are true. Truth an d 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 commonly 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 bring ins and one and only one conclusion. The effronterys 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 st atement 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 somewhat 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 Copyri ght 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 conclusion. By process of elimination the other statements in the argument are the premises. Example Tortured prisoners will say anything just to relieve t he 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 anticipant 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 reviewi ng 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 about to be stated. Sometimes a hit indicator can be used to identify more than one premise. Consider the following argument It is vitally importa nt that wilderness areas be preserved, for wilderness provides essential habitat for wildlife, including jeopardize 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 seat 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 tec hnological spinoffs.Furthermore, at current patronage 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 lieu 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 expenditures in the years ahead. When restructuring arguments such as this, one should remain as good as possible to the original version, while at the same time attend ing 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. single 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 th e overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. erves scarcely to introduce the general topic, or only when makes a bye comment, it should not be taken 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 proscribe 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. immense 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 these reasons, Congress must make a opinionated effort to cut overall spending and raise taxes.Politicians who ignore this universe 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, however, proposition and statement are used interchangeably. Note on the History of Logic The person who is generally credited 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 chief accomplishment is called syllogistic logic, a grade 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 in general 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 remainder, another(prenominal) Greek philosopher, Chrysippus (280206 b. c. ), one of the founders of the Stoic school, devel oped 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 laid 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 learning 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 medical student 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 fiber of general terms to concepts in the mind rather than to natures existing outside(a) the mind, as Aristotle had held. In addition, Abelard distinguished arguments that arevalid because of their form from those that are valid because of their content, but he held that only formal validity is the perfect or conclusive variety. The present text