Logical Reasoning Lesson 1: Fundamentals of Argument Analysis and Question Types

Introduction to Logical Reasoning

• Date: June 15, 2026

• Objective: Establish a foundation for identifying and analyzing Logical Reasoning (LR) passages and question stems.

• The Question Stem: The stem establishes the correct criterion for the answer choice. There is only ONE correct answer for every logical reasoning question.

Identifying Passage Types

Before analyzing an argument, one must determine if a passage contains an argument at all.

• Facts Passage:

  • Represents a set of facts without trying to convince the reader of a specific point.

  • Usually lacks keyword indicators (to be discussed later).

  • Example: "It is sunny today, etc., etc."

  • Identification Strategy: Ask yourself, "Is there a point being made?"

  • Goal: Just follow the criterion provided in the question stem.

• Argument Passage:

  • Defined by the presence of a "point."

  • Strategy: Pause and take a moment to ensure you clearly understand the argument.

  • Identification Tasks:

  • Identify the Conclusion.

  • Identify the Premise or Premises supporting that conclusion.

  • Action Item: Underline every conclusion in the LR section.

Argument Structure and Keywords

Understanding how an author arrived at a conclusion is vital. You must evaluate if premises are supported and if the overall argument is valid.

• Keyword Indicators for Conclusions:

  • Conclude / it can be concluded that

  • Therefore

  • It follows that

  • Accordingly

  • Hence

  • Result

  • Thus

  • We may infer

  • So

  • Consequently

  • For this reason

• Keyword Indicators for Premises:

  • Since

  • For

  • As indicated by

  • Because

  • For the reason that

  • May be inferred from

  • Given that

  • In that

• Placement Caveat: Beware that conclusions can appear anywhere. They can come before premises, after them, or even in the middle of a passage.

Validity and Flaws

• Valid Argument:

  • An argument is valid if the conclusion follows logically from the premises, assuming those premises are true.

  • Important: Logic is distinct from being "right" or factual in a real-world sense. The focus is on the logical flow.

• Invalid (Flawed) Argument:

  • An argument is invalid if the conclusion does not necessarily follow from the stated premises.

  • A "jump" in logic occurs between the premises and the conclusion.

  • Even if the premises are true, the argument can be flawed if the conclusion isn't guaranteed by those premises.

  • Tactics: When attacking an argument, look for where the conclusion fails to follow logically.

Common Question Stem Types (1991–2017 Data)

• Main Point (MP):

  • Goal: Identify the main argument or specific point of the passage.

  • Classification: These are technically "Must Be True" questions with an additional requirement. The answer choice cannot just be true; it must specifically represent the main point/goal of the passage.

• Argument Structure (AS):

  • Goal: Identify the role a specific line or sentence plays within the argument.

  • Requirement: The answer choice must be true and correctly identify the objective of that sentence.

• Must Be True (MBT):

  • Goal: If the statements in the passage are true, what else must follow? Identify the most strongly supported statement.

• Strengthen (Most commonly tested 1991–2017):

  • Goal: Identify the strongest line or piece of information given the context to support the argument.

  • Sub-strains of Strengthen:

  • Strengthen with Necessary Premise: Information the argument needs to function.

  • Strengthen with Sufficient Premise: Information that "checks the box" to guarantee the conclusion. Look for "bridge indicators."

• Weaken:

  • Goal: Attack the argument.

• Methods of Reasoning (2nd most common type):

  • Goal: Describe how the argument is built or the strategy used.

  • Sub-strain: Error in Reasoning. Identify the specific structural reasoning that is working against the argument.

• Parallel Reasoning:

  • Goal: Find an answer choice that has the exact same method of reasoning as the original passage.

  • Flawed Parallel Reasoning: Match the flawed reasoning of the passage to a flawed answer choice. If the passage is flawed, assume you must match the flaw even if the stem doesn't explicitly state it.

• Paradox:

  • Goal: Reconcile a contradiction or discrepancy within the passage. Something in the passage does not make sense; you must find the explanation that resolves the discrepancy.

• Cannot Be True:

  • Goal: Identify the answer choice that is "Must Be False."

  • Strategy: Look for something that directly conflicts with or disproves the information in the passage. Use keywords that undermine the passage's premises.

Advanced Argument Exchange and Principles

• Date: June 16, 2026

• Point of Argument: Determine what the passage best connects to.

• Point at Issue: Identify the specific conflict or point of disagreement within the context of the question.

• Misinterpretation: Identify where person $Y$ misinterprets person $X$'s point or statement.

• Illustration: Find the best holistic match for a "picture" or scenario described.

• Argument Evaluation:

  1. What information is most useful when evaluating an exchange?

  2. What is the overall evaluation of the LR question?

• Principle Questions:

  • Goal: Identify or apply a broad, general rule that matches the situation.

  • Methodology: Many principles contain strict conditions. Look for keywords such as $\text{only if}$, $\text{required}$, $\text{most}$, and $\text{always}$. Your answer choice must contain matching formal logic.

Logical Opposites and True/False Dynamics

Use these equivalencies to navigate logic-based question stems:

• $\text{Must be true} \leftrightarrow \text{Cannot be false}$

• $\text{Not necessarily true} \leftrightarrow \text{Could be false}$

• $\text{Could be true} \leftrightarrow \text{Not necessarily false}$

• $\text{Cannot be true} \leftrightarrow \text{Must be false}$

Lecture concluded at 44:55 for LR Lesson 1.