LSAT Explanation PT 40, S3, Q14: Franklin: The only clue I have

LSAT Question Stem

Which one of the following provides the strongest grounds for criticizing Franklin's reasoning? 

Logical Reasoning Question Type

This is a Flaw question. 

Correct Answer

The correct answer to this question is A. 

LSAT Question Complete Explanation

Let's first analyze the argument in the passage. Franklin is trying to identify a practical joker based on the handwriting on a note. He initially suspects Miller, but since the handwriting does not match Miller's, he concludes that the joker is someone else. The structure of the argument can be broken down as follows:

Premise: The handwriting on the note is the only clue to the joker's identity.

Premise: The handwriting on the note does not match Miller's.

Conclusion: The joker is apparently someone other than Miller.

Now let's think of an "Evaluate" question for this argument: "Could there be any other possible explanations for the mismatch in handwriting?"

The question type for this problem is Flaw, and it asks us to identify the strongest grounds for criticizing Franklin's reasoning. Let's examine each answer choice:

a) It fails to consider the possibility that there was more than one practical joker.

This answer choice points out a flaw in Franklin's reasoning, as he assumes that there is only one joker. It is possible that Miller could be one of multiple jokers or that she had someone else write the note. This is a strong criticism of the argument and is the correct answer choice.

b) It fails to indicate the degree to which handwriting samples should look alike in order to be considered of the same source.

This answer choice is not relevant to the flaw in Franklin's reasoning. The argument does not involve comparing two handwriting samples to determine if they are from the same source. This answer choice is incorrect.

c) It provides no explanation for why Miller should be the prime suspect.

Franklin does mention that Miller has always been jealous of him, which serves as a reason for suspecting her. However, providing an explanation for why Miller is the prime suspect is not necessary for the logic of the argument. This answer choice is incorrect.

d) It provides no explanation for why only one piece of evidence was obtained.

Franklin is not obligated to explain why only one piece of evidence was obtained. This answer choice does not address a flaw in his reasoning and is incorrect.

e) It takes for granted that if the handwriting on the note had been Miller's, then the identity of the joker would have been ascertained to be Miller.

This answer choice misinterprets Franklin's conclusion. He argues that since the handwriting isn't Miller's, the joker is not Miller. It would be illogical for him to assume the Mistaken Negation of his own conclusion. This answer choice is incorrect.

In conclusion, the correct answer choice is (a), as it identifies a flaw in Franklin's reasoning by pointing out that he fails to consider the possibility of multiple practical jokers or other explanations for the mismatch in handwriting.