Critical Thinking & Argument Evaluation Flashcards

A researcher argues: 'Countries with higher chocolate consumption per capita consistently produce more Nobel laureates per capita. Therefore, chocolate consumption stimulates cognitive development.' Which flaw MOST seriously undermines this argument?

Answer: The argument conflates a population-level correlation with an individual-level causal mechanism without ruling out confounding variables such as national wealth.

This is an ecological fallacy combined with unsupported causal inference. Even if the correlation at the country level is real, it does not establish a mechanism at the individual level, and an obvious confound — national wealth — plausibly explains both variables. Options A and C raise minor measurement issues but do not strike at the core logical error. Option D misidentifies the fallacy entirely.

Consider this argument: 'We should not trust the results of the climate study because the lead researcher once worked for an oil company.' Suppose it is later confirmed that the researcher did have a prior financial interest. How does this affect the argument's logical status?

Answer: The argument remains a genetic fallacy; the conflict of interest is relevant evidence warranting scrutiny of the methodology, but does not itself refute the findings.

Confirming a conflict of interest raises the prior probability of bias and justifies closer methodological scrutiny, but it does not logically refute the conclusion. The argument remains a genetic fallacy at its core — truth or falsity of the findings must be assessed on evidential grounds. Option A overstates the implication; Option C commits a non-sequitur (motive ≠ act); Option D misapplies 'appeal to authority.'

An argument runs: 'Either we implement mandatory community service or youth civic engagement will collapse. We cannot afford mandatory community service. Therefore, youth civic engagement will collapse.' A critic responds that the first premise presents a false dilemma. For this rebuttal to succeed, what must the critic demonstrate?

Answer: That at least one viable alternative exists that could sustain youth civic engagement without mandatory community service.

A false dilemma fallacy occurs when an argument presents exactly two options as exhaustive when others exist. To rebut it, the critic must identify a genuine third (or more) option — not dispute the cost figure or point to the conclusion's current falsity. Option A attacks a different premise and does not address the dilemma structure. Option B is about the conclusion's truth value, not the argument's structure. Option D challenges the second premise, not the first.

Passage: 'The more firefighters sent to a fire, the greater the property damage tends to be. Clearly, firefighters cause property damage and we should reduce fire department funding.' Beyond the obvious correlation-causation error, which ADDITIONAL logical problem is present?

Answer: The argument commits suppressed evidence by ignoring that larger fires both attract more firefighters and cause more damage, making firefighter numbers a proxy for fire severity.

The correlation-causation error is compounded by suppressed evidence: fire severity is a confounding variable that independently drives both the number of firefighters dispatched and the extent of damage. This makes the number of firefighters a proxy indicator, not a cause. Option A is incorrect because no single-case limitation is mentioned. Option B is a stretch — 'cause' is used consistently. Option D would require an implicit chain of consequences not present in the text.

An ethics board argues: 'Our hospital has never had a patient escape from the secure psychiatric ward; therefore, our security protocols are effective.' A logician identifies this as an instance of 'survivorship bias.' Which description BEST explains why that label applies here?

Answer: The argument draws on the absence of failures without considering whether the cases observed are an unrepresentative sample — specifically, that successful escapes might have been reclassified or that the ward only houses low-risk patients.

Survivorship bias occurs when a conclusion is drawn from only the surviving or observable cases while the 'failures' are invisible or excluded. Here, if escapes were underreported, if the patient population is systematically low-risk, or if near-misses were not counted, the absence of recorded escapes is not reliable evidence of protocol effectiveness. Option A raises a benchmark issue — valid but not survivorship bias. Option C is hasty generalisation. Option D would be circular reasoning, which requires the premise and conclusion to be definitionally identical — they are not here.

A debater claims: 'My opponent has not proven that economic inequality causes violent crime; therefore, economic inequality does not cause violent crime.' Which principle of argumentation does this MOST precisely violate?

Answer: The burden of proof distribution: the absence of proof for a claim is not equivalent to proof of its negation, especially for empirical causal claims.

This is an argument from ignorance (ad ignorantiam). The fact that the opponent has not proven a proposition does not establish the proposition's negation — particularly for a complex empirical causal question where the evidence may be incomplete or contested. Option A (principle of charity) concerns interpretation of arguments, not the logic of this inference. Option C misapplies non-contradiction, which governs statements simultaneously held. Option D makes a valid philosophical point about induction vs. deduction but is too narrow to identify the primary fallacy.