LSAT Logical Reasoning: Must Be False Questions

Introduction

• Presenter: Patrick from LSAT Lab
• Focus: Must be false questions in the logical reasoning section
• Frequency: Rare (~1% of questions on most tests)

Identifying Must Be False Questions

• Keywords: "must be false," "cannot be true"
• Inference questions: referred to as "statements" rather than arguments
• Requires identifying contradictions

Types of Must Be False Questions

• Direct Contradictions: Look for explicit conflicts between statements
• Incompatibilities: Situations where statements are the least compatible
• Conditional logic: Important for spotting contradictions, e.g., "only if," "unless"

Reading and Analyzing Statements

• Focus on facts, not arguments
• Look for relationships: conditional, causal, comparative
• Use of conditional logic: Diagramming may help

Types of Correct Answers

• Contradict Conditional Statements: Violating a necessary condition
• Contradict Possible Inferences: Combining multiple facts to infer wrong conclusions

Example Analysis: Solomon's Behavior

• Scenario: Politeness in eating
• Wrong Inferences: Example of using a wet-nap as impolite
• Correct Contradiction: Solomon double dips in fresh cocktail sauce, conflicting with his rule of only double dipping when sauce is low

Example Analysis: Shrimp Blogging

• Scenario: Shrimp eating habits and blogging
• Correct Contradiction: Contradiction in shrimp weight inference, e.g., heavier shrimp eaten now vs. month ago

Real LSAT Example Analysis

• Common Triggers: Conditional words like "unless"
• Counterexample: Establishing a principle and contradicting it directly
• Example choices: Analyzing correct vs. incorrect options based on contradicting conditionals

Conclusion

• Key Points: Spotting keywords, reading statements carefully, anticipating contradictions
• Trap Answers: Unopposed, out of scope, weak, or supported by the passage
• Study Tips: Focus on conditional logic, use reasoning structures, beware of distractions like unnecessary details

Resources

• Additional videos and lessons at LSAT Lab and on their YouTube channel