LSAT Explanation PT 42, S2, Q26: Astronomer: I have asserted that our

LSAT Question Stem

The reasoning in the astronomer's argument is flawed because this argument 

Logical Reasoning Question Type

This is a Flaw question. 

Correct Answer

The correct answer to this question is B. 

LSAT Question Complete Explanation

First, let's analyze the structure of the astronomer's argument:

Premise: The astronomer claims that there are not enough meteoroids and cosmic debris in our solar system to have caused the extensive cratering on the far side of the moon.

Premise: The astronomer's opponents have failed to prove this thesis false, and their evidence is inconclusive.

Conclusion: The opponents should admit that the astronomer's thesis is correct.

The question type for this problem is a Flaw question. We are asked to identify the flaw in the astronomer's reasoning.

Now, let's evaluate each answer choice:

a) The argument does not criticize the astronomer's opponents personally, but rather their arguments and the inconclusive evidence they have presented. This answer choice is incorrect.

b) This answer choice correctly identifies the flaw in the astronomer's reasoning. The astronomer infers the truth of their thesis simply because it has not been proven false. Just because the opponents' evidence is inconclusive does not automatically make the astronomer's thesis correct. This answer choice is correct.

c) The astronomer's thesis already implies that alternative explanations for the cratering exist, as they claim that meteoroids and cosmic debris are not the cause. So, the argument does not ignore the possibility of alternative explanations. This answer choice is incorrect.

d) The argument does not presume that the astronomer's thesis should not be subject to rational discussion and criticism. In fact, the astronomer is engaging in a debate with their opponents about the thesis. This answer choice is incorrect.

e) The argument does not fail to define the key word "meteoroids." The term is used consistently throughout the argument and does not create confusion or ambiguity. This answer choice is incorrect.

In conclusion, the correct answer choice is (b). The astronomer's reasoning is flawed because they infer the truth of their thesis from the mere claim that it has not been proven false.