Logical Reasoning: Drawing and Testing Conclusions on the LSAT

Must Be True (MBT)

A question type that asks for a statement logically forced by the stimulus, guaranteed to be true if the stimulus is true.

Valid inference

The skill of deducing conclusions that are logically consistent with given premises or statements.

Quantifier examples

Terms such as 'all,' 'some,' 'most,' and 'none' that define the scope of statements in logical reasoning.

Conditional statements

Statements that express a relationship where one condition leads to the fulfillment of another (e.g., 'If A, then B').

Contrapositive

An equivalent statement derived from a conditional statement, where the antecedent and consequent are negated and switched.

Safe inferences

Logical conclusions that can be confidently drawn from given premises, often involving restatements or combined facts.

Denial testing

A technique used in logical reasoning to determine if an answer choice is necessarily false by imagining a scenario where it could be false.

Common wrong moves in MBT

Errors like affirming the consequent or denying the antecedent that lead to invalid conclusions.

Most Strongly Supported (MSS)

A question type that asks for the answer choice best supported by the stimulus, without requiring it to be 100% guaranteed.

Modest wording

Language that reflects caution or likelihood, often using terms like 'some,' 'likely,' or 'tends' in MSS answers.

Resolution mindset

The thought process used to tackle 'Resolve the Paradox' questions by identifying the specific tension in conflicting statements.

Different groups resolution

Recognizing that paradoxical statements may refer to different populations or subsets, providing clarity between them.

Net effect resolution

Identifying that two opposing influences can coexist, where one effect suppresses or counteracts the other.

Cannot Be True (CBT)

A question type that asks for a statement that must be false if the stimulus is accepted as true.

Direct contradiction

A type of CBT answer that states the opposite of a fact presented in the stimulus.

Testing answers in CBT

Evaluating answer choices by checking if they can logically coexist with the stimulus; if they can't, they are correct.

Resolve the Paradox

A reasoning task that presents seemingly incompatible statements and requires identifying new information to reconcile them.

Confounding variable

An outside factor that alters the relationship between two variables, often revealing the true nature of the data presented.

Timing shifts resolution

An explanation that clarifies inconsistencies by indicating that facts were relevant at different times.

Different definitions resolution

Clarifying that the same term is used with different meanings in contradictory statements.

Common resolution traps

Mistakes made when selecting answers that do not directly address the tension or contradiction presented in the stimulus.

Scope shift

A common error where an answer discusses a different group, timeline, or context than the stimulus supports.

Collectively exhaustive reasoning

The reasoning approach that ensures all possibilities are accounted for in resolving paradoxes or contradictions.

Logical reasoning skill

The ability to analyze arguments and determine their validity, often tested through various question types on exams like the LSAT.

Strengthen/Weaken reasoning

Analytical strategies used to assess how well facts or arguments support or detract from a specific conclusion.

Facts vs. assumptions

Recognizing the difference between what is stated in the stimulus (facts) and what must be inferred or assumed.

Common patterns in logical reasoning

Recurring themes in LSAT questions, such as distinguishing between MBT, MSS, CBT, and Resolve the Paradox types.