LSAT Logical Reasoning Basics

Jun 19, 2025

Overview

This lecture covers the basics of LSAT Logical Reasoning, including question types, core reasoning skills, and strategies for tackling common question formats.

The Purpose of Logical Reasoning Questions

  • Logical reasoning questions are designed to test reading ability, reasoning ability, and mental discipline.
  • Reading ability includes understanding meanings and recognizing the structure of reasoning.
  • Recognizing arguments involves identifying the main point (conclusion) and the support (premises).
  • The relationship between support and conclusion is critical for evaluating arguments.

Types of Logical Reasoning Questions

  • Flaw questions: Identify why the support does not guarantee the conclusion.
  • Required assumption questions: Find what must be true for the argument to work.
  • Sufficient assumption questions: Identify what, if assumed, guarantees the conclusion.
  • Strengthen/weaken questions: Find what strengthens or weakens the argument’s connection between support and conclusion.
  • Supporting principle questions: Identify a broad rule that would fill the argument’s reasoning gap.
  • Match the flaw questions: Find an argument with a reasoning flaw similar to the stimulus.

Common Techniques and Strategies

  • Always read the question stem first to know your task.
  • Identify the conclusion and support before evaluating answer choices.
  • Eliminate obviously irrelevant or insufficient answer choices.
  • Plug each answer into the argument to see if it fills the reasoning gap or matches the requirement.

Non-Argument Question Types

  • Identify the conclusion: Find the main point of the argument.
  • Identify the method of reasoning: Explain how the author supports the conclusion.
  • Identify the role: Specify the role played by a highlighted statement.
  • Match the reasoning: Select the answer with a parallel argument structure.
  • Inference questions: Choose what must be true or is most supported by the information.
  • Explain questions: Reconcile two seemingly contradictory facts.
  • Identify the disagreement: Determine what two speakers disagree about.
  • Identify an example: Select the answer that best illustrates a principle from the stimulus.

Example Problem Approaches

  • For sufficient assumption questions, seek an answer that guarantees the conclusion when assumed true.
  • For identify an example questions, match actions in choices against the criteria described, eliminating those driven by self-interest or social conformity if the principle requires pure motives.

Key Terms & Definitions

  • Conclusion — The main point or claim in an argument.
  • Support/Premise — The evidence or reasons given to justify the conclusion.
  • Flaw — A logical gap or error in the reasoning.
  • Assumption — A missing piece that must be true for the argument to hold.
  • Principle — A general rule or law applied to the argument.
  • Inference — A statement that must be true based on the information provided.

Action Items / Next Steps

  • Practice identifying argument structure (conclusion and support) in sample questions.
  • Review and attempt various logical reasoning question types, focusing on argument-based formats.
  • Stay objective and avoid overthinking answer choices, especially for non-argument questions.