Critical Thinking & Argument Evaluation Flashcards

A researcher concludes: 'Countries with higher chocolate consumption per capita have more Nobel Prize winners per capita, therefore eating chocolate boosts cognitive performance.' Which flaw most fundamentally undermines this argument?

Answer: The argument conflates correlation at the population level with causation at the individual level, compounding an ecological fallacy

The argument commits two compounding errors: it treats correlation as causation AND commits an ecological fallacy — inferring individual-level effects from aggregate population data. Even if the correlation were real, wealthy nations may simply consume more chocolate AND produce more Nobel laureates due to a common third factor (prosperity), while no individual's chocolate intake necessarily affects their cognition. The other flaws are real but secondary; this structural flaw is what fundamentally destroys the inference.

An opponent of a proposed policy argues: 'Senator Khumalo supports this environmental bill, but she owns shares in a solar energy company — so her argument for the bill cannot be trusted.' This reasoning is best classified as:

Answer: Ad hominem circumstantial, which challenges her motives but leaves her argument's logical validity intact

This is an ad hominem circumstantial fallacy. Pointing to Senator Khumalo's financial interest may be relevant context for assessing her credibility, but it does not address whether her argument for the bill is logically sound. A conflict of interest can explain why someone holds a position without showing the position itself is wrong. The opponent must refute the argument on its merits. Note: this is distinct from a general ad hominem (attacking character) — here the attack targets her circumstances, not her personality.

Consider the following argument: 'If the government implements price controls, shortages will result. Shortages have not resulted. Therefore, the government did not implement price controls.' Which form of reasoning does this represent, and is it valid?

Answer: Modus tollens — valid, because denying the consequent allows us to deny the antecedent

The argument takes the form: If P then Q; not-Q; therefore not-P. This is modus tollens (denying the consequent), which is a formally valid argument form. If it is genuinely true that price controls always produce shortages, and there are no shortages, then we can validly infer price controls were not implemented. This is distinct from affirming the consequent (If P then Q; Q; therefore P — invalid) and denying the antecedent (If P then Q; not-P; therefore not-Q — invalid).

A report states: 'Eight out of ten dentists recommend Brand X toothpaste.' A critical thinker should PRIMARILY question which of the following before accepting this as strong evidence?

Answer: Whether 'recommend' was defined consistently and what the full range of options dentists were given to choose from

The most critical issue is the ambiguity in both 'recommend' and the survey design. If dentists were asked 'Do you recommend Brand X over using no toothpaste at all?' rather than 'Which brand do you most recommend?', the 80% figure becomes trivially inflated. Similarly, if dentists could select multiple brands, recommending Brand X doesn't distinguish it. Without knowing exactly what question was asked and what choices were available, the statistic is uninterpretable. This is a precision-of-evidence problem more fundamental than the other concerns.

Two students debate a historical claim. Student A says: 'You cannot prove that economic factors did NOT cause the conflict, so we should accept that they did.' Student B says: 'The burden of proof lies with the person making the positive claim.' Which student demonstrates stronger critical thinking, and why?

Answer: Student B, because the burden of proof rests with those asserting a claim, and Student A's reasoning is an argument from ignorance

Student B is correct. Student A's reasoning is an argument from ignorance (ad ignorantiam): concluding that a claim is true simply because it has not been disproven. This is a formal fallacy. The inability to disprove something is not positive evidence for it. The burden of proof rests with the person making the positive assertion — they must supply evidence supporting it, not merely note the absence of refutation. While historiography does use inference to the best explanation under uncertainty, that is distinct from treating unprovability as proof.

An editorial argues: 'We must either dramatically increase police funding or accept that violent crime will rise uncontrollably. Since no government can accept rising crime, we must dramatically increase police funding.' A sophisticated critic would identify this as flawed primarily because:

Answer: The argument presents a false dilemma by ignoring alternative interventions that could reduce crime without dramatically increasing police funding

This is a classic false dilemma (false dichotomy): the argument artificially restricts the options to only two when others exist — e.g., social programs, judicial reform, urban planning, community intervention, or reallocating existing budgets. By forcing an either/or choice between only two options, the argument eliminates the logical space where most real policy debate occurs. While the emotive language (option C) and the normative premise (option D) are real weaknesses, they are secondary; the structural false dilemma is the primary critical flaw because it makes the entire reasoning framework invalid.