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Flaw in the Reasoning Questions - Coggle Diagram
Flaw in the Reasoning Questions
Nature of Flaw Questions
Same as Method of Reasoning but explicitly flawed.
Stems indicate: “flawed,” “vulnerable,” “fallacious,” etc.
Advantage: you know an error exists → identify it before choices.
Correct answer: describes the error in general terms.
Wrong answers: often describe stimulus parts but not the error.
Value of Knowing Common Errors
LSAT recycles classic flawed forms.
Benefits:
Quickly spot reasoning errors in stimulus.
Recognize common trap answers (e.g., attacking the source).
Preparation strategy: study stock flaws + how LSAT phrases them.
Common Errors of Reasoning
Uncertain Use of a Term (Equivocation)
Word/phrase used with different meanings.
Examples in answers: “ambiguous use,” “equivocates,” “shifts meaning.”
Source Argument (Ad Hominem)
Attacks person/source, not argument.
Forms: motives, character, actions.
Common phrasing: “directed against proponent,” “attacks character.”
Circular Reasoning
Conclusion restates premise.
LSAT wording: “assumes what it seeks to establish,” “argues circularly.”
Conditional Reasoning Errors
Mistaken Negation / Mistaken Reversal.
Core flaw: confusing sufficient vs. necessary.
Clues: words “sufficient,” “necessary,” “required.”
Mistaken Cause and Effect
Forms:
Post hoc (sequence → cause).
Correlation = causation.
Ignores alternate cause.
Reverses cause/effect.
Clues: “cause,” “effect.”
Straw Man
Misrepresents opponent’s claim → easier to refute.
Clues: “distorts,” “misdescribes,” “refutes a distorted version.”
Lack of Relevant Evidence
Evidence irrelevant or absent.
Clues: “irrelevant data,” “fails to give reason,” “unrelated evidence.”
Internal Contradiction
Author makes conflicting statements.
LSAT wording: “inconsistent,” “mutually contradictory,” “assumes something later denied.”
Appeal Fallacies
Authority – irrelevant expert.
Popular Opinion/Numbers – majority belief = truth.
Emotion – persuasion by emotion, not reason.
Survey Errors
Biased sample, bad question construction, false responses.
LSAT wording: “unrepresentative sample,” “generalizes improperly.”
Exceptional Case / Overgeneralization
Small cases → universal conclusion.
Wording: “generalizes from too small a sample,” “bases claim on few instances.”
Composition & Division
Composition: part → whole.
Division: whole → part.
Phrasing: “what is true of each part must be true of the whole,” etc.
False Analogy
Compares unlike cases.
Wording: “treats as similar two things that differ critically.”
False Dilemma
Only two options presented, ignores others.
Wording: “fails to consider some students may be neither A nor B.”
Misuse of Evidence
Lack of evidence → claim false.
Lack of evidence against → claim true.
Some evidence against → claim false.
Some evidence for → claim true.
Wording: “failure to prove = denial,” “lack of evidence against = truth.”
Time Shift Errors
Past/future conditions assumed constant.
Wording: “treats past as guarantee of future.”
Numbers/Percent Errors
Confusing % with actual numbers (and vice versa).
Wording: “confuses percentage with overall amount.”
Strategy Reminders
Always check premise–conclusion link.
Spot keywords (“cause,” “sufficient,” “necessary,” “authority”).
Expect stock LSAT phrasing in answer choices.