LSAT Explanation PT 28, S3, Q21: If the law punishes littering, then
LSAT Question Stem
Which one of the following exhibits a flawed pattern of reasoning most similar to that in the argument above?
Logical Reasoning Question Type
This is a Parallel Flaw question.
Correct Answer
The correct answer to this question is D.
LSAT Question Complete Explanation
Let's first analyze the argument in the passage. The passage contains a conditional statement: "If the law punishes littering, then the city has an obligation to provide trash cans." This can be represented as follows:
LPL = Law Punishes Littering
OTC = City has an Obligation to provide Trash Cans
LPL ‚Üí OTC
The argument then states that the law does not punish littering (¬LPL), and concludes that the city has no such obligation (¬OTC). This is a Mistaken Negation, as it should be ¬OTC → ¬LPL, but the argument claims ¬LPL → ¬OTC.
Now, let's look at the question type, which is a Parallel Flaw question. We need to find an answer choice that exhibits a flawed pattern of reasoning most similar to the argument in the passage.
Answer choice (A) contains a Mistaken Reversal, not a Mistaken Negation like the passage.
Answer choice (B) is close to a contrapositive but has some differences in the time and context of the statements. This is not the same error as the passage, so it's incorrect.
Answer choice (C) contains a Mistaken Reversal, not a Mistaken Negation like the passage.
Answer choice (D) is the correct answer. It contains a Mistaken Negation, similar to the passage. It can be diagrammed as:
FL = Flight Late
MM = Missed the Committee Meeting
FL ‚Üí MM
The argument states that the flight is not late (¬FL) and concludes that the person will not miss the meeting (¬MM). This is a Mistaken Negation, just like the passage.
Answer choice (E) contains a contrapositive, which is valid reasoning. Since we're looking for a flawed pattern of reasoning, this answer choice is incorrect.
In conclusion, the correct answer is (D), as it exhibits a flawed pattern of reasoning (Mistaken Negation) most similar to the argument in the passage.