LSAT LOGICAL REASONING BIBLE A Comprehensive System for Attacking the Logical Reasoning Section of the LSAT powerscore_lrb_2018.indb 1 12/14/2017 11:33:17 AM Copyright © 2002-2018 by PowerScore Incorporated. All Rights Reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means electronic, mechanical, photocopying, recording, scanning, or otherwise, without the prior written permission of the Publisher. Parts of this book have been previously published in other PowerScore publications and on the powerscore.com website. All actual LSAT® content reproduced within this work is used with the permission of Law School Admission Council, Inc., (LSAC) Box 40, Newtown, PA 18940, the copyright owner. LSAC does not review or endorse specific test-preparation materials, companies, or services, and inclusion of licensed LSAT content within this work does not imply the review or endorsement of LSAC. 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The LSAT Bible Series , The Logical Reasoning Bible , The TM TM Logic Games Bible , The Reading Comprehension Bible ,The LSATs Deconstructed ,The LSAT Training TM TM TM Type Series , The Logical Reasoning Primary Objectives , The Conclusion Identification Method , The TM TM TM Fact Test , The Uniqueness Rule of Answer Choices , The Justify Formula , Mechanistic Approach , TM TM TM TM The Supporter/Defender Assumption Model , The Assumption Negation Technique , The Opposition TM TM Construct , The Logic Ladder , The Negative Logic Ladder , The Complete Table of Formal Logic Additive TM TM TM Inferences , The Elemental Attack , Test of Abstraction , The Variance Test , The Idea Umbrella , The TM TM TM TM TM Agree/Disagree Test , and The Agree/Agree Test are the exclusive service marked property of PowerScore. TM TM Any use of these terms without the express written consent of PowerScore is prohibited. The logical reasoning, logic games, and reading comprehension systems, question classification systems, diagramming systems, and the overall approach to solving each question used in this book were created by PowerScore. Any use or reproduction of any such classifications, systems, or solutions without the express written consent of PowerScore is prohibited. Published by PowerScore Publishing, a division of PowerScore Incorporated 57 Hasell Street Charleston, SC 29401 Author: David M. Killoran Special thanks to Terry Bray, Bekki Cait, and Steven G. Stein for editorial and design assistance. Manufactured in Canada 12 12 20 17 ISBN: 978-0-9912992-2-5 powerscore_lrb_2018.indb 2 12/14/2017 11:33:17 AM “ A goal without a plan... ” is just a wish. -Antoine de Saint-Exupéry Get a free LSAT Self-Study Plan based on the amount of time you have remaining before the LSAT at: students.powerscore.com/self-study powerscore_lrb_2018.indb 3 12/14/2017 11:33:26 AM It’s more than test prep. 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Learn more about our Admissions Consulting at powerscore.com. powerscore_lrb_2018.indb 6 12/14/2017 11:33:45 AM Contents Chapter One: Introduction Introduction ....................................................................................................................................3 Additional Resources .....................................................................................................................4 A Brief Overview of the LSAT ........................................................................................................6 The Logical Reasoning Section ................................................................................................6 The Analytical Reasoning Section ............................................................................................7 The Reading Comprehension Section ......................................................................................7 The Experimental Section .........................................................................................................7 The Writing Sample...................................................................................................................7 The LSAT Scoring Scale ................................................................................................................8 The LSAT Percentile Table ............................................................................................................9 The Use of the LSAT ....................................................................................................................10 Chapter Two: The Basics of Logical Reasoning The Logical Reasoning Section ...................................................................................................13 The Section Directions ............................................................................................................13 The Parts of a Logical Reasoning Question ...........................................................................15 Approaching the Questions—What To Read First? ................................................................15 Analyzing the Stimulus.................................................................................................................17 The Range of Stimulus Topics—Including Science ................................................................18 Speaker Identifiers ..................................................................................................................19 LSAT Vocabulary .....................................................................................................................21 Arguments versus Fact Sets ...................................................................................................23 Identifying Premises and Conclusions ....................................................................................24 One Confusing Indicator Form ................................................................................................27 Premise and Conclusion Recognition Mini-Drill ......................................................................28 Additional Premise Indicators .................................................................................................32 Counter-Premise Indicators ....................................................................................................33 Additional Premise and Counter-Premise Recognition Mini-Drill ............................................35 Recognizing Conclusions Without Indicators ..........................................................................38 Complex Arguments.....................................................................................................................40 A Commonly Used Construction .............................................................................................43 Decoding Text ..............................................................................................................................45 Killer Sentences ......................................................................................................................45 Uncovering Meaning: Context, Simplification, and Rephrasing ..............................................45 Reference Words ....................................................................................................................50 Reference Substitution ............................................................................................................52 the powerscore lsat logical reasoning bible i powerscore_lrb_2018.indb 1 12/14/2017 11:33:45 AM Understanding the Stimulus .........................................................................................................53 Truth versus Validity ................................................................................................................53 Argument Analysis ..................................................................................................................53 Inferences and Assumptions ...................................................................................................55 The Mind of an LSAT Author ...................................................................................................56 Read the Fine Print .................................................................................................................57 Tracking Indicators and Concepts ...........................................................................................58 Scope ......................................................................................................................................59 Notating Arguments ................................................................................................................59 Summarizing Arguments .........................................................................................................61 Fluidity of Analysis and Concept Application ...........................................................................61 Final Chapter Note .......................................................................................................................62 Premise and Conclusion Analysis Drill ....................................................................................63 Chapter Three: The Question Stem and Answer Choices The Question Stem ......................................................................................................................77 Analyzing the Question Stem ..................................................................................................78 The Thirteen Logical Reasoning Question Types ...................................................................79 Question Type Notes...............................................................................................................88 Question Type Variety .............................................................................................................89 Question Stem Wording Variations .........................................................................................90 Double-Question LSAT Logical Reasoning Stimuli .................................................................91 “Most” in Question Stems .......................................................................................................92 Identify the Question Stem Drill ..............................................................................................93 “Except” and “Least” in Question Stems .................................................................................99 Except and Least Identify the Question Stem Mini-Drill ........................................................103 Prephrasing Answers ............................................................................................................106 The Answer Choices ..................................................................................................................107 Question Approach Review .......................................................................................................110 Tricks of the Trade .....................................................................................................................112 Answer Transferring ..............................................................................................................113 Filling in the Ovals .................................................................................................................113 Practicing with Time ..............................................................................................................114 Final Chapter Note .....................................................................................................................115 ii the powerscore lsat logical reasoning bible powerscore_lrb_2018.indb 2 12/14/2017 11:33:45 AM Chapter Four: Must Be True and Most Strongly Supported Questions Must Be True Questions ............................................................................................................119 Most Strongly Supported Questions ...........................................................................................121 Prephrasing with Must Be True and Most Strongly Supported Questions ............................122 Returning to the Stimulus ......................................................................................................124 New Information and the Idea Umbrella ...............................................................................125 Primary Objective #4 and Modifier Words Revisited .............................................................126 Language: Negatives, Double Negatives, and Triple Negatives ...........................................129 Correct Answers in Must Be True and Most Strongly Supported Questions Reviewed ........131 Incorrect Answers in Must Be True and Most Strongly Supported Questions ..........................132 Idea Application: An Analysis of Correct and Incorrect Answers ...........................................135 Stimulus Opinions versus Assertions ....................................................................................138 Final Note ..............................................................................................................................140 Must Be True and Most Strongly Supported Question Type Review ....................................140 Must Be True and Most Strongly Supported Question Problem Set .....................................142 Chapter Five: Main Point Questions Main Point Questions .................................................................................................................155 Two Incorrect Answer Types .................................................................................................156 Fill in the Blank Questions .........................................................................................................160 Main Point—Fill in the Blank Questions ................................................................................160 Final Chapter Note ................................................................................................................163 Main Point Question Type Review ........................................................................................163 Fill in the Blank Question Type Review .................................................................................164 Must Be True and Main Point Question Stem Mini-Drill ........................................................165 Main Point Question Problem Set .........................................................................................168 Chapter Six: Conditional Reasoning Sufficient and Necessary Conditions .............................................................................................173 To Diagram or Not to Diagram ..............................................................................................174 Three Logical Features of Conditional Reasoning ................................................................175 Valid and Invalid Statements .................................................................................................176 Symbolic Representation and Diagramming Negatives ........................................................179 Valid and Invalid Statement Recognition Mini-Drill................................................................181 The Multiplicity of Indicator Words ........................................................................................184 How to Recognize Conditionality ..........................................................................................186 The Unless EquationTM ..........................................................................................................187 Conditional Reasoning Diagramming Drill ............................................................................188 Conditional Reasoning and Must Be True/Most Strongly Supported Problems ..........................197 the powerscore lsat logical reasoning bible iii powerscore_lrb_2018.indb 3 12/14/2017 11:33:45 AM Conditional Linkage ..............................................................................................................202 Diagramming Conditional Statements with Subscripts .........................................................206 Diagramming Either/Or Statements ......................................................................................208 The Exception to the Rule: “Than Either” ..............................................................................212 “Only,” “Only If,” and “The Only” ............................................................................................212 Multiple Sufficient and Necessary Conditions .......................................................................214 The Double Arrow .................................................................................................................217 The Double-Not Arrow ..........................................................................................................218 Either/Or, Multiple Condition, and Double Arrow Diagramming Drill .....................................220 Nested Conditionals ..............................................................................................................227 Conditional Reasoning Review .............................................................................................230 Either/Or Review ...................................................................................................................232 Multiple Conditions Review ...................................................................................................233 Unusual Arrows Review ........................................................................................................234 When to Diagram Revisited ..................................................................................................234 Don’t Force Conditionality On Every Problem ......................................................................236 Final Note ..............................................................................................................................236 Sufficient and Necessary Question Problem Set ..................................................................237 Chapter Seven: Weaken Questions Weaken Questions .....................................................................................................................251 How to Weaken an Argument ...............................................................................................253 Common Weakening Scenarios............................................................................................255 Three Incorrect Answer Traps ...............................................................................................255 Weaken Questions Analyzed ................................................................................................256 Weakening Conditional Reasoning .......................................................................................263 Final Note ..............................................................................................................................268 Weaken Question Type Review ............................................................................................268 Weaken Question Problem Set .............................................................................................270 Chapter Eight: Cause and Effect Reasoning What is Causality? .....................................................................................................................281 How to Recognize Basic Causality .......................................................................................281 The Difference Between Causality and Conditionality ..........................................................282 Causality in the Conclusion versus Causality in the Premises .............................................283 Situations That Can Lead to Errors of Causality ...................................................................284 The Central Assumption of Basic Causal Conclusions .........................................................285 How to Attack a Basic Causal Conclusion ............................................................................287 Diagramming Causality .........................................................................................................288 A Basic Cause and Effect Problem Analyzed .......................................................................289 iv the powerscore lsat logical reasoning bible powerscore_lrb_2018.indb 4 12/14/2017 11:33:45 AM