LNAT Evaluating Argument Strengths 4 — Questions and Answers
Question 1: An argument concludes that because violent video games are popular among teenagers who commit crimes, video games cause violence. What is the strongest counter-argument?
- Video games are not popular among all teenagers
- Correlation between two variables does not establish that one causes the other (Correct answer)
- Most teenagers who play violent games do not commit crimes
- Crime statistics vary between regions
Correct answer: Correlation between two variables does not establish that one causes the other
Correlation does not imply causation; a common background factor could explain both gaming habits and criminal behavior.
Question 2: Which type of reasoning moves from specific observations to a general conclusion?
- Deductive reasoning
- Inductive reasoning (Correct answer)
- Abductive reasoning
- Analogical reasoning
Correct answer: Inductive reasoning
Inductive reasoning generalizes from specific cases to broader conclusions, making it inherently probabilistic.
Question 3: A passage argues that since ancient Romans used lead pipes and suffered health problems, modern societies using plastic pipes will also suffer health problems. What is the main flaw?
- The argument appeals to tradition
- The analogy is weak because plastic and lead have very different chemical properties (Correct answer)
- Ancient Romans are not a reliable historical source
- The argument ignores the benefits of modern plumbing
Correct answer: The analogy is weak because plastic and lead have very different chemical properties
A false analogy occurs when two compared situations differ in ways that are critical to the conclusion.
Question 4: A think-tank report argues that cutting corporation tax increases government revenue because companies expand and pay more total tax. Which assumption is essential to this argument?
- All companies will reinvest tax savings into expansion
- The tax cut will be large enough to stimulate significant economic growth (Correct answer)
- Government revenue currently relies primarily on corporation tax
- Companies currently pay the full statutory tax rate
Correct answer: The tax cut will be large enough to stimulate significant economic growth
The argument depends on the cut being sufficient to trigger enough growth that total tax receipts actually increase, a condition known as the Laffer curve assumption.
Question 5: Which of the following statements about argument structure is correct?
- A sound argument can have false premises
- A valid argument guarantees a true conclusion regardless of premise truth
- A valid argument with all true premises must have a true conclusion (Correct answer)
- An invalid argument cannot have a true conclusion
Correct answer: A valid argument with all true premises must have a true conclusion
Soundness requires both validity (correct logical form) and true premises, which together guarantee a true conclusion.
Question 6: An advocate argues: 'My proposed law has worked in Sweden, so it will work here.' Which factor most threatens this argument by analogy?
- Sweden is a smaller country than the US
- Sweden and the US differ significantly in legal culture, enforcement capacity, and social norms (Correct answer)
- The advocate did not consult Swedish lawmakers
- No law works perfectly in any country
Correct answer: Sweden and the US differ significantly in legal culture, enforcement capacity, and social norms
Relevant structural differences between the two countries undermine the analogy's ability to support a prediction about outcomes.
Question 7: A student argues that because every swan she has ever seen is white, all swans must be white. This argument is best described as:
- A deductively valid argument
- An inductively weak argument due to limited sampling (Correct answer)
- A sound argument with true premises
- A cogent argument because the evidence is consistent
Correct answer: An inductively weak argument due to limited sampling
The argument is inductively weak because the sample is small and geographically limited, leaving open the existence of non-white swans (black swans exist in Australia).
LNAT Evaluating Argument Strengths 4
An argument concludes that because violent video games are popular among teenagers who commit crimes, video games cause violence.
What is the strongest counter-argument?