Analytical and Critical Reasoning: Argument Structure
Analytical and Critical Reasoning tests whether you can extract an argument's structure, judge what follows from its premises, and spot unstated assumptions. The exam rewards precision about validity, sufficiency, and evidence strength rather than verbal fluency.
Core rules
- Validity concerns form, not truth: an argument is valid if the conclusion cannot be false when the premises are true. Soundness adds actually true premises.
- Conditionals: "If P then Q" permits modus ponens (P, so Q) and modus tollens (not Q, so not P). It does not permit affirming the consequent (Q, so P) or denying the antecedent (not P, so not Q).
- Necessary versus sufficient: P is sufficient for Q if P guarantees Q; P is necessary if Q cannot occur without P. "Only if" introduces a necessary condition.
- Assumption questions: locate the gap between evidence and conclusion; the correct answer makes the argument work, and its negation should weaken the argument.
- Evidence: distinguish correlation from causation, base rates from individual cases, and anecdote from systematic data.
Worked example
"Every applicant scoring above 70 on the entrance test is invited to interview. Maria was invited. Therefore Maria scored above 70." The first premise makes a high score sufficient for an invitation, not necessary for it: applicants may be invited on other grounds. The inference affirms the consequent and is invalid. It would become valid only with the stronger premise that exactly those scoring above 70 are invited.
Traps
- Attacking a claim's truth when the question asks about its logical support.
- Confusing "some" with "all", or "not all" with "none".
- Accepting a conclusion because it is plausible rather than because the premises force it.
- Missing scope words such as "only", "unless", and "at least".