LSAT Logical Reasoning – Core Concepts (Ch. 2–3 Lecture)

Vocabulary flashcards summarizing essential LSAT Logical Reasoning terminology, objectives, indicators, and question-family structures covered in the lecture notes.

LSAT Logical Reasoning

Section of the LSAT that tests the ability to evaluate short arguments and fact sets.

Stimulus

The paragraph or set of statements presented before the question stem.

Question Stem

The sentence that follows the stimulus and asks what you must do (e.g., weaken, support).

Answer Choices

The five possible responses from which you must select the correct answer.

Argument

A set of statements containing at least one premise offered in support of a conclusion.

Set of Facts (Fact Set)

A stimulus that only presents information without drawing a conclusion.

Premise

A fact, proposition, or statement offered to support a conclusion.

Conclusion

The statement or judgment that purportedly follows from the premises.

Premise Indicators

Signal words such as “because,” “since,” “for example,” and “given that” introducing premises.

Conclusion Indicators

Signal words such as “therefore,” “thus,” “so,” and “hence” introducing conclusions.

Additional Premise

A non-essential statement added to bolster an argument, often introduced by “furthermore” or “moreover.”

Additional Premise Indicators

Words like “furthermore,” “besides,” and “in addition” that precede extra supportive material.

Counter-Premise

A statement that introduces contrast, concession, or potential weakness in an argument.

Counter-Premise Indicators

Words such as “however,” “but,” “although,” and “on the other hand” that signal opposition.

Simple Argument

An argument containing one premise and one conclusion.

Complex Argument

An argument with multiple premises and/or intermediate conclusions.

Validity (LSAT sense)

The degree to which the conclusion logically follows from the premises, regardless of real-world truth.

Inference

A statement that must be true or is highly supported given the information in the argument.

Assumption

An unstated premise that must be true for the argument’s reasoning to work.

Quantity Indicators

Words that refer to amount, such as “all,” “most,” “many,” “some,” or “few.”

Probability Indicators

Words that refer to likelihood, such as “must,” “probably,” “likely,” “could,” or “rarely.”

Scope

The range of ideas that the premises and conclusion cover within an argument.

Primary Objective #1

Decide whether the stimulus contains an argument or just a set of facts.

Primary Objective #2

If an argument is present, identify its conclusion; if not, examine each fact.

Primary Objective #3

Determine whether an argument is strong or weak (valid or invalid).

Primary Objective #4

Read closely and know exactly what the author says; avoid generalizing.

Prephrase

Mentally formulating a predicted answer before reviewing the answer choices.

Contenders and Losers

The process of dividing answer choices into those that could be correct (contenders) and those that are clearly wrong (losers).

13 LSAT Question Types

Includes Must Be True, Main Point, Point at Issue, Assumption, Justify, Strengthen, Resolve Paradox, Weaken, Method, Flaw, Parallel, Evaluate, and Cannot Be True.

Family 1: PROVE

Question family (Types 1, 2, 3, 9, 10, 11) where the stimulus is used to prove an answer choice.

Family 2: HELP

Question family (Types 4, 5, 6, 7) where answer choices help or support the stimulus.

Family 3: HURT

Question family (Type 8) where answer choices weaken the stimulus.

Family 4: DISPROVE

Question family (Type 13) where the stimulus is used to prove an answer choice cannot be true.