An accurate description beats a familiar label
A flaw answer must describe an error the argument actually makes. Do not choose “correlation and causation” merely because two things appear together, or “circular reasoning” because a conclusion seems unsupported. State the unsupported step in ordinary language, then compare it with the answer choices.
Circular reasoning assumes what it purports to establish, perhaps in slightly different words. Equivocation shifts a key expression’s meaning between premise and conclusion. A false dilemma treats a limited set of possibilities as exhaustive without justification. Each diagnosis requires identifying the precise assumption or shift.
Track the level of a claim
A property of every part need not belong to the whole: every page can be inexpensive to print while a thousand-page volume is costly. A property of the whole need not belong to each part: an expert committee can include a nonexpert observer. Analogies also require relevant similarities; superficial resemblance does not establish similarity in the feature that matters.
A speaker may attack a weaker substitute for an opponent’s actual position. That defeats the substitute, not the original argument. A personal criticism can be relevant when assessing a witness’s credibility, but does not refute an independently supported inference simply because the speaker is unpleasant or inconsistent.
Avoid diagnosing disagreement as illogic
People may share evidence but disagree about how to weigh liberty, cost, fairness, or risk. Identify the evaluative premise instead of pretending a different priority is automatically a logical fallacy. A deduction can also be valid while a premise is false, vague, or contested. Criticize the right component.
A useful objection says what the problem is and why it matters. “This is a hasty generalization” becomes more helpful as “The sample includes only people who attended an optional event, so it may not represent members who could not attend.” That explanation also suggests what better evidence would look like.
Worked example
Every component in this kit weighs less than one kilogram. Therefore the entire kit weighs less than one kilogram.
- Premise
- Each component individually has a weight below one kilogram.
- Unsupported transfer
- The conclusion assigns the same weight bound to the collection.
- Counterexample
- Three components weighing half a kilogram each satisfy the premise while totaling one and a half kilograms.
- Description
- The argument transfers a property of individual parts to the whole without considering their combined weight.
Check your understanding
Take it into practice
Name the exact inference, construct a possible counterexample, and only then attach a flaw label.