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Complete Question Explanation


Flaw in the Reasoning. The correct answer choice is (B)

This is problem set features an Evidence error. In this problem, the astronomer
falls into the second error from the Errors in the Use of Evidence section, where “Lack of evidence
against a position is taken to prove that position is true.” Answer choice (B) describes this mistake.

The astronomer’s argument is structured as follows:

     Premise: I have asserted that our solar system does not contain enough meteoroids and
     other cosmic debris to have caused the extensive cratering on the far side of the
     moon.

     Premise: My opponents have repeatedly failed to demonstrate the falsity of this thesis.
     Their evidence is simply inconclusive.

     Conclusion: They [my opponents] should admit that my thesis is correct.

Answer choice (A): The argument in the stimulus does not include a Source attack. There is a
difference between stating that an opponent’s argument is wrong (which is legitimate) and attacking
the character of that opponent (a Source flaw). Always look to see if the author attacks the person or
the position; a legitimate argument can sometimes appear questionable if the author uses weighted
language such as, “My opponents are deluded in believing that my thesis is incorrect.” Although
that phrasing sounds like a personal attack, it is just a very strong way of stating that the author’s
opponents are incorrect, and it is not a Source attack.

Answer choice (B): This is the correct answer.

Answer choice (C): The astronomer’s thesis asserts that meteoroids and other cosmic debris are not
the cause of the cratering on the far side of the moon. By definition, therefore, the astronomer allows
for alternate explanations for the cratering.

Answer choice (D): There is no presumption in the argument similar to the one described in this answer.

Answer choice (E): This answer describes the Uncertain Use of a Term, but the argument does not
use “meteoroids” in an inconsistent way.

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