Formal Logic and LSAT Master Document Flashcards

A comprehensive set of vocabulary flashcards covering LSAT formal logic, logical reasoning argument types, flaws, and reading comprehension strategies based on the Master Document notes.

Sufficient condition

The 'trigger' or 'if' term that, if true, ensures and absolutely guarantees the necessary term; also means 'enough'.

Necessary condition

The 'result/requirement' or 'then' term that must be true if the sufficient term is triggered; also means 'needed'.

Contrapositive

A logical rule where you reverse the sufficient and necessary terms, negate each term, and change 'and' to 'or' (and vice-versa).

'And' (Logical Signifier)

Means both terms are needed to trigger the rule, or both results will occur.

'Or' (Logical Signifier)

Means either will trigger the rule, or at least one result will occur.

A only if B

Translates as $A \rightarrow B$.

A if B

Translates as $B \rightarrow A$.

'Unless' (Translating)

Can be translated by replacing 'unless' with 'if not' at the start of the sentence, or by treating it as the necessary term and negating the sufficient term.

Main Point

The author's primary conclusion or what the rest of the argument is supporting; the ultimate takeaway of the stimulus.

Role of a Statement

A question type asking for the specific purpose of a statement within the structure of an argument (e.g., evidence, premise, or conclusion).

Conclusion (VIPCAR)

The assertion, evaluation, or recommendation the author wants us to believe; types include Valid judgment, If/then, Prediction, Comparison, Assertion of fact, and Recommendation.

Evidence

The facts, studies, or contentions the author believes support or establish the conclusion; the 'why' of the argument.

Subsidiary conclusion

A conclusion that functions as evidence to support the final conclusion; it is evidence in disguise as a conclusion.

Mismatched Concepts (MMC)

An assumption-family argument where a key term in the evidence appears unrelated to one in the conclusion or is not stated in the evidence at all.

Overlooked Possibilities (OP)

An assumption-family argument where terms are related but the conclusion is too strong, failing to consider objections or alternative explanations.

Sufficient Assumption

An unstated premise that, when added to the evidence, guarantees the argument's conclusion.

Necessary Assumption

An unstated premise without which the conclusion cannot follow from the evidence; required for the argument to work.

Denial Test

A backup strategy for Necessary Assumption questions where you negate the answer choice; if the negated choice makes the conclusion impossible, it is correct.

Flaw

The reasoning error resulting from a gap in the argument; describing why the argument fails to logically reach its conclusion.

Correlation vs. Causation

A logical flaw that concludes a causal relationship ($X$ causes $Y$) when the evidence only establishes a correlation or mere coincidence.

Slippery Slope

A rare flaw that concludes a final, extreme outcome based on an assumed chain of causal events.

Equivocation

A flaw where the author uses the same word or term inconsistently between the conclusion and the evidence.

Ad hominem

A method of argument flaw where the author attacks an opponent's personal credibility rather than the substance of their argument.

Must Be True Inference

A deduction that unequivocally follows from the stimulus facts with zero outside knowledge required.

Some / A Few / Many

Quantities meaning anywhere from one to all, but must be at least 1 ($\neq 0$).

Most / A majority

Quantities meaning over half (>50\text{%}), which includes the possibility of all.

Paradox Question

A question type where you must identify a fact that helps resolve an apparent discrepancy or contradiction in the stimulus.

Topic (Reading Comprehension)

The overall subject of a Reading Comprehension passage.

Scope (Reading Comprehension)

The particular aspect of the topic the author is focusing on.

Purpose (Reading Comprehension)

The author's reason for writing the passage, often expressed as a verb (e.g., to argue, to suggest, to critique).

180 (Wrong Answer Type)

An answer choice that is the logical opposite of what the right answer should be.

Faulty Use of Detail (FUD)

An answer choice that states something true from the passage or stimulus but is irrelevant to the specific question asked.

Global Question (RC)

A question that asks about the big picture of the entire passage, such as the organization or primary purpose.