LNAT Argument Evaluation 5 — Questions and Answers
Question 1: A columnist claims: 'Since the unemployment rate fell after tax cuts were introduced, tax cuts reduce unemployment.' Which additional piece of evidence would most strengthen this causal claim?
- Tax cuts are popular with voters
- Countries that did not cut taxes saw unemployment rise during the same period (Correct answer)
- The government also reduced regulation at the same time as the tax cuts
- Economists disagree about the effects of tax policy
Correct answer: Countries that did not cut taxes saw unemployment rise during the same period
A control comparison showing divergent outcomes for non-treatment cases strengthens the causal inference.
Question 2: Which of the following is a necessary condition for an inductive argument to be considered strong?
- The conclusion must be certain given the premises
- The premises must make the conclusion more likely to be true (Correct answer)
- The argument must contain no unstated assumptions
- All premises must be verifiable by direct observation
Correct answer: The premises must make the conclusion more likely to be true
A strong inductive argument is one where the premises make the conclusion probable, not certain.
Question 3: An editorial argues: 'We must act on climate change now. Anyone who disagrees is in the pay of fossil fuel companies.' This is an example of:
- Poisoning the well / ad hominem (Correct answer)
- A legitimate appeal to motivation
- A sound empirical argument
- An appeal to authority
Correct answer: Poisoning the well / ad hominem
Dismissing all opposition by impugning their motives rather than addressing their arguments is poisoning the well.
Question 4: Which of the following best describes the role of a 'counter-example' in evaluating a universal claim?
- It weakens but cannot disprove a universal claim
- A single counter-example is sufficient to disprove a universal claim (Correct answer)
- Counter-examples are only relevant for inductive arguments
- Counter-examples must come from peer-reviewed research to be valid
Correct answer: A single counter-example is sufficient to disprove a universal claim
Logic dictates that one genuine exception falsifies a claim of the form 'All X are Y.'
Question 5: A passage argues that renewable energy cannot replace fossil fuels because the wind doesn't always blow and the sun doesn't always shine. Which response most effectively rebuts this?
- Renewable energy is cheaper than it used to be
- Storage technology and grid diversification can compensate for intermittency, making continuous supply feasible (Correct answer)
- Many countries have invested heavily in renewable energy
- Fossil fuels also experience supply interruptions
Correct answer: Storage technology and grid diversification can compensate for intermittency, making continuous supply feasible
Directly addressing the intermittency problem by citing technological solutions undermines the core premise of the argument.
Question 6: In the context of the LNAT, which of the following best characterises a 'principle' in an argument?
- A specific factual claim that can be empirically tested
- A general rule or value that, if accepted, supports the conclusion in the specific case (Correct answer)
- The main conclusion of the argument
- An unstated assumption that contradicts the conclusion
Correct answer: A general rule or value that, if accepted, supports the conclusion in the specific case
A principle is a broad normative or logical rule that bridges general values to specific conclusions.
Question 7: Which of the following most accurately describes the difference between 'weakening' and 'undermining' an argument?
- They are synonyms in formal logic
- Weakening reduces the probability of the conclusion; undermining attacks the structure or a key premise directly (Correct answer)
- Undermining only applies to deductive arguments
- Weakening requires statistical evidence while undermining does not
Correct answer: Weakening reduces the probability of the conclusion; undermining attacks the structure or a key premise directly
Weakening makes the conclusion less likely, while undermining can destroy a premise or reveal a structural flaw.
LNAT Argument Evaluation 5
A columnist claims: 'Since the unemployment rate fell after tax cuts were introduced, tax cuts reduce unemployment.' Which additional piece of evidence would most strengthen this causal claim?