Rank 11 by frequency | 51 questions in corpus (2.1% of all questions)
Asks the test-taker to identify a statement that, if true, would most undermine, challenge, or cast doubt on an argument, claim, or theory presented in the passage. This is an RC version of Logical Reasoning's Weaken question type. The "if true" framing means the test-taker must accept each answer choice as hypothetically true and evaluate its effect on the passage's argument.
Weaken has 4 distinct subtypes based on the language of attack:
Direct weaken language. - "Which one of the following, if true, would most weaken the author's argument?" - "The author's position would be most weakened if which one of the following were true?" - "Which one of the following, if true, most seriously weakens the author's claim?"
What makes it distinct: The most direct phrasing. "Weaken" is the operative word.
The most common subtype. Uses softer attack language. - "Which one of the following, if true, would most seriously undermine [X]?" - "Which one of the following, if true, would most undermine the author's explanation?" - "Which one of the following, if true, would cast the most doubt on [X]?" - "Which one of the following, if true, most calls into question [X]?"
What makes it distinct: "Undermine" and "cast doubt" are more precise than "weaken" — they signal that the answer doesn't need to destroy the argument, just make it less convincing.
Uses confrontational language. - "Which one of the following, if true, most challenges the author's contention?" - "Which one of the following, if true, would present the greatest challenge to the new proposal?"
What makes it distinct: "Challenge" implies a more direct confrontation — the answer actively opposes the argument rather than merely eroding its support.
Asks about vulnerabilities. - "Which one of the following, if true, would provide the strongest objection to the criticism in the passage?"
Mixed phrasings: - "Which one of the following, if true, most clearly weakens [X]?" - "Which one of the following, if true, would cast the most doubt on [X]'s argument?"
Unlike LR Weaken questions (which target a standalone argument), RC Weaken questions target a specific argument within the passage. This is usually: - A causal claim ("X causes Y") - A theoretical prediction ("If theory T is correct, then we should observe O") - A historical explanation ("Event E happened because of factor F") - A policy recommendation ("We should do X because it will achieve Y") - An evaluative claim ("Method M is superior to method N")
Key insight from expert analysis: RC Weaken questions usually tackle a small, specific argument that's only in one paragraph, not the main point. The test-taker must isolate the targeted sub-argument.
Every argument has at least one of these weaknesses: - Alternative cause: If the argument says X causes Y, evidence that Z also causes Y weakens it - Broken mechanism: Evidence that the stated mechanism doesn't work as claimed - Counterexample: A case where the argument's prediction fails - Undermined premise: Evidence that a key factual premise is wrong - Scope limitation: Evidence that the argument doesn't apply as broadly as claimed - Reversed correlation: Evidence that the observed relationship runs in the opposite direction
The correct answer presents a hypothetical fact that targets the argument's key vulnerability: - Must be external to the passage (new information, not already stated) - Must directly affect the argument's logic (not just tangentially related) - Must make the conclusion less likely to be true (not just provide alternative support for it) - Must accept the "if true" framing — the test-taker should not question the answer's plausibility
Trap Type 1: Irrelevant Information Relates to the passage's topic but doesn't affect the targeted argument. If the argument is about why birds migrate, information about bird feeding habits might be topically related but logically irrelevant.
Trap Type 2: Actually Strengthens Provides evidence that supports rather than undermines the argument. Test-takers who misidentify the argument's direction may select this.
Average 22.2 words. Nearly always includes "if true" — the hypothetical framing that distinguishes this from Inference or Specific Reference. The stem typically names or references the specific argument being targeted.
Average 19.9 words. Choices present hypothetical facts or findings. Each answer is a self-contained claim that the test-taker must accept as true and evaluate for its effect on the passage's argument.
Key pattern: The correct answer usually targets the causal link or key assumption of the passage's argument, not a peripheral detail.
Source: PT10, Q14 > "Which one of the following, if true, would most weaken the author's contention that fifteenth-century Venetian artists 'had no practical experience of the large-scale representation of familiar religious stories' (lines 40-42)?"
Correct Answer (C): "Many of the artists who produced Venetian narrative paintings with religious subjects served as apprentices in Tuscany, where they had become familiar with the technique of painting frescoes."
Source: PT70, Q7 > "Which one of the following, if true, would most undermine the claim that prions cause CJD?"
Correct Answer (E): "A newly developed antibacterial drug currently undergoing clinical trials is proving to be effective in reversing the onset of CJD."
Source: PT17, Q18 > "Which one of the following circumstances would most seriously undermine the conclusion 'Such a tax would induce industry to substitute less-polluting fuels for those carrying a higher tax' (lines 13-15)?"
Correct Answer (A): "The fuel taxed at the highest rate costs considerably less to buy than fuels taxed at lower rates."