LSAT Question Stem

Sue challenges Anne's reasoning by 

Logical Reasoning Question Type

This is a Method of Reasoning question. 

Correct Answer

The correct answer to this question is D. 

LSAT Question Complete Explanation

This LSAT problem features two speakers, Anne and Sue, who are discussing Halley's Comet and its recent flare. The question type is Method of Reasoning (MOR), and we are asked to identify how Sue challenges Anne's reasoning. Let's first analyze their arguments:

Anne's Argument:

1. Premise: Halley's Comet recently flared brightly enough to be seen by a telescope while far from the Sun.

2. Premise: No comet has ever been observed to flare so far from the Sun before.

3. Conclusion: Such a flare must be highly unusual.

Sue's Argument:

1. Premise: Usually, no one bothers to try to observe comets when they are so far from the Sun.

2. Premise: This flare was observed only because an observatory was tracking Halley's Comet very carefully.

3. Conclusion: Anne's conclusion is nonsense.

Anne uses causal reasoning to argue that the flare is highly unusual because no comet has ever been observed to flare so far from the Sun before. Sue counters this by providing an alternative cause: no one usually tries to observe comets when they are so far from the Sun. Now, let's discuss each answer choice:

a) Sue does not criticize Anne's use of the term "observed" as being vague. She only provides an alternative explanation for why the flare was observed. This answer choice is incorrect.

b) Sue does not point out an inconsistency between two of Anne's claims. Instead, she offers an alternative explanation for the evidence Anne cites. This answer choice is incorrect.

c) Sue does not present evidence that directly contradicts Anne's evidence (premises). She only contradicts Anne's conclusion by providing an alternative explanation. This answer choice is incorrect.

d) This answer choice is correct. Sue offers an alternative explanation for the evidence Anne cites by suggesting that no one usually tries to observe comets when they are so far from the Sun, and this flare was observed because an observatory was tracking Halley's Comet carefully.

e) Sue does not undermine any of Anne's evidence while agreeing with her conclusion. Instead, she undermines Anne's conclusion while not directly addressing Anne's evidence (premises). This answer choice is incorrect.

In conclusion, the correct answer is choice (d), as Sue challenges Anne's reasoning by offering an alternative explanation for the evidence Anne cites.