Evaluating Argument Strengths Flashcards

An argument concludes that banning fast food near schools will reduce childhood obesity because children cannot access it during school hours. Which flaw best describes this reasoning?

Answer: It ignores that children can access fast food outside school hours

The argument ignores that the restriction only applies during a fraction of children's daily time, leaving ample opportunity for access.

A politician argues: 'Crime rates fell after we hired more police, so more police caused the crime reduction.' This argument is weakened most by which consideration?

Answer: Other factors, such as economic improvement, may have caused the reduction

Post hoc reasoning mistakes temporal sequence for causation; other concurrent changes could explain the crime reduction.

Which of the following most strengthens the argument that mandatory helmet laws reduce cycling fatalities?

Answer: Countries that introduced mandatory helmet laws saw immediate drops in cycling deaths

Direct evidence of fatality reductions following the introduction of mandatory helmet laws provides strong causal support.

A company claims its supplement is effective because 80% of users reported feeling better. What is the primary weakness of this evidence?

Answer: It relies on self-reported outcomes without a control group

Without a control group, it is impossible to separate the supplement's effect from the placebo effect or natural recovery.

Argument: 'No evidence of harm has been found, so the chemical must be safe.' This reasoning exemplifies which fallacy?

Answer: Appeal to ignorance

An appeal to ignorance treats the absence of evidence as positive evidence of safety, which is logically invalid.

A researcher finds that students who eat breakfast score higher on tests. She concludes breakfast causes better performance. Which additional finding would most weaken her conclusion?

Answer: Wealthier students are more likely to eat breakfast and also have better study resources

If socioeconomic status correlates with both breakfast eating and study resources, it could be the real cause of higher scores.

Which principle underlies the idea that a strong inductive argument can still have a false conclusion?

Answer: The premises of an inductive argument only make the conclusion probable, not certain

Inductive reasoning yields probabilistic conclusions; even well-supported inductive conclusions can be overturned by new evidence.