Sequenced. Precise. Elegant. Clear. Hurley’s A Concise Introduction to Logic, 11th Edition How to Make an Origami Crane Make your own origami crane using these instructions and the perforated sheet of paper included in your book. 1. Start with a square piece 2. Turn the paper over to the 3. Using the creases you have made, bring the top 3 of paper, colored side up. white side. corners of the model down to the bottom corner. Fold in half and open. Then Fold the paper in half, crease Flatten model. fold in half the other way. well and open, and then fold again in the other direction. About the Cover The iconic red crane on the cover of this new edition of Hurley’s, 4. Fold top triangular 5. Fold top of model 6. Open the uppermost flap of the model, bringing it upwards A Concise Introduction to Logic flaps into the downwards, crease and pressing the sides of the model inwards at the same time. center and unfold. well and unfold. Flatten down, creasing well. symbolizes the qualities that make it the most successful logic text on the market. We have chosen origami to symbolize this text’s careful sequencing, precision, elegance, and clarity. Couple an icon steeped in tradition with a clean, modern design, and you will quickly get a sense of the qualities that make this new edition of Hurley the 7. Turn model over 8. Fold top flaps into 9. Repeat on other side. 10. Fold both ‘legs’ of 11. Inside Reverse and repeat Steps 4-6 the center. model up, crease Fold the “legs” best yet. Along with instructions, each on the other side. very well, then along the creases you just made. new text includes a sheet of red paper unfold. so that you can bring the cover to life. This exercise serves as a metaphor for the process of learning logic. It is challenging, requires practice, but can Finished Crane. be fun. Ideas for other ways to create your own origami can be found at 12. Inside Reverse Fold one side to make a www.origami-resource-center.com. head, then fold down the wings. Source: www.origami-fun.com 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. A CONCISE INTRODUCTION TO Logic 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. A CONCISE INTRODUCTION 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 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. 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 publisher 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 current editions, and alternate formats, please visit www.cengage.com/highered to search by ISBN#, author, title, or keyword for materials in your areas of interest. 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. A Concise Introduction to Logic, Eleventh © 2012, 2008, 2006 Wadsworth, Cengage Learning Edition ALL RIGHTS RESERVED. No part of this work covered by the copyright Patrick J. Hurley herein may be reproduced, transmitted, stored, or used in any form or by any means graphic, electronic, or mechanical, including but not Publisher: Clark Baxter limited to photocopying, recording, scanning, digitizing, taping, Web Senior Sponsoring Editor: Joann Kozyrev distribution, information networks, or information storage and retrieval Development Editor: Florence Kilgo systems, except as permitted under Section 107 or 108 of the 1976 Assistant Editor: Nathan Gamache United States Copyright Act, without the prior written permission of the publisher. Editorial Assistant: Michaela Henry Media Editor: Diane Akerman For product information and technology assistance, contact us at Marketing Manager: Mark T. Haynes Cengage Learning Customer & Sales Support, 1-800-354-9706 Marketing Coordinator: Josh Hendrick For permission to use material from this text or product, Marketing Communications Manager: submit all requests online at www.cengage.com/permissions. Laura Localio Further permissions questions can be emailed to [email protected]. Content Project Manager: Alison Eigel Zade Senior Art Director: Jennifer Wahi Library of Congress Control Number: 2010924757 Print Buyer: Paula Vang Student Edition: Production Service: Elm Street Publishing Services ISBN-13: 978-0-8400-3417-5 Internal designer: Yvo Riezebos ISBN-10: 0-8400-3417-2 Cover designer: Jeff Bane of CMB Design Partners Wadsworth Cover image: Courtesy of Getty Images: Red 20 Channel Center Street origami crane on white table (image Boston, MA 02210 number 85592979) USA Compositor: Integra Software Services Pvt. Ltd. Cengage Learning is a leading provider of customized learning solutions with offi ce locations around the globe, including Singapore, the United Kingdom, Australia, Mexico, Brazil, and Japan. Locate your local offi ce at: international.cengage.com/region Cengage Learning products are represented in Canada by Nelson Education, Ltd. For your course 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 America 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 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. 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 insuffi cient evidence. –W. K. Cliff ord Nothing can be more important than the art of formal reasoning 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 Preface xiii PART I INFORMAL LOGIC 1 Basic Concepts 1 2 Language: Meaning and Defi nition 78 3 Informal Fallacies 119 PART II FORMAL LOGIC 4 Categorical Propositions 197 5 Categorical Syllogisms 259 6 Propositional Logic 310 7 Natural Deduction in Propositional Logic 380 8 Predicate Logic 442 PART III INDUCTIVE LOGIC 9 Analogy and Legal and Moral Reasoning 509 10 Causality and Mill’s Methods 529 11 Probability 554 12 Statistical Reasoning 571 13 Hypothetical/Scientifi c Reasoning 593 14 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