LSAT Logical Reasoning: Building, Analyzing, and Evaluating Arguments

Argument

A set of statements where at least one statement (the conclusion) is claimed to follow from other statements (the premises).

Conclusion

The main claim the author is trying to get you to accept in an argument.

Premise

A reason offered in support of the conclusion.

Premise indicators

Words like 'because,' 'since,' and 'for' that signal premises in an argument.

Conclusion indicators

Words like 'therefore,' 'thus,' and 'consequently' that signal conclusions in an argument.

Intermediate conclusion

A claim supported by premises, which is then used as a premise to support the main conclusion.

Background facts

Scene-setting information that makes the argument understandable.

Causation

A claim stating that one thing produces or influences another.

Correlation

A relationship where two variables change together, but one may not cause the other.

Causal reasoning

The process of determining whether a cause leads to an effect.

Conditionals

Statements that express a relationship between conditions, typically in 'if-then' form.

Sufficient condition

A condition that guarantees the outcome when met.

Necessary condition

A condition that must be true for the outcome to occur.

Contrapositive

From 'If A, then B,' it states 'If not B, then not A.'

Quantifiers

Words like 'all,' 'some,' and 'most' used to express the quantity involved in a claim.

Universal claim

A statement that applies to all members of a category.

Existential claim

A statement that asserts the existence of at least one member of a category.

Strengthen an argument

To provide additional evidence or reasoning that increases the likelihood of the conclusion being true.

Weaken an argument

To introduce evidence or reasoning that decreases the likelihood of the conclusion being true.

Assumption

An unstated claim that the argument relies on; if it’s false, the argument collapses.

Necessary assumption

An assumption that must be true for the argument to work.

Sufficient assumption

An assumption that, if true, guarantees the conclusion of the argument.

Inference question

A question that requires you to draw logical conclusions from the passage.

Must Be True (MBT) question

A type of inference question asking for a statement that is forced by the passage.

Most Strongly Supported (MSS) question

A question that asks for the statement that has the best support, even if not guaranteed.

Method of reasoning question

A question asking you to describe what the argument does in abstract terms.

Role of a statement question

A question asking what function a specific statement plays in the argument.

Principle question

A question that asks for a general rule that applies to the argument.

Discrepancy question

A question that presents conflicting facts and asks for an explanation that resolves them.

Parallel reasoning question

A question that asks for an answer choice whose reasoning matches the stimulus.

Common flaw

A recurring pattern of bad reasoning in arguments.

Causal flaw

A flaw that assumes a causal connection without sufficient evidence.

False dilemma

A logical flaw that presents only two options when more exist.

Out of scope

An answer choice that is related to the topic but does not impact the logical structure of the argument.

Strengthening assumption

An assumption that, if true, adds support to the argument's conclusion.

Circular reasoning flaw

When the conclusion is assumed in the premises without independent support.

Sampling flaw

A flaw arising from biased samples or misrepresented survey results.

Premises

Statements that provide support for the conclusion.

Conclusion

The main point or claim made by an argument.

Contradictory statement

A statement that directly opposes another.

Scope shift

When an argument moves from a specific to a general claim without justification.

Negation test

A method to determine if an assumption is necessary by negating the statement.

Premise-premise relationship

A comparison or connection between two premises in an argument.

Argument flaw

A defect in reasoning that undermines the argument's validity.

Analogical reasoning

Drawing conclusions based on the similarities between two different situations.

Resolving paradox question

A question that asks for information that reconciles conflicting facts.

Comparative analysis

Evaluating the strength and relevance of different answer choices based on the argument.

Diagramming

The practice of visually representing the logical structure of arguments to clarify relationships.