Logical reasoning PrepTest 153 · Section 2 · Question 13

Incorrect. This matches the anticipation of "a difference" between the things being compared, but instead of pointing out the fallacy of equivocation in the stimulus, it's just giving us an arbitrary example of a difference between the periodic table and dictionaries. This difference doesn't seem to affect their usefulness for their respective applications.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Weaken

Stimulus Summary:
Here we have an argument by comparison. Chemists use the periodic table as a convenient source of agreed-upon background information relevant to their work; therefore, legal interpreters are justified in using ordinary dictionaries to resolve issues with terminology.

Strategy Overview:
Begin by identifying the conclusion and asking if it's causal. In this case, it's not, so move on to treating this as a Flaw question. What flaw already present in the stimulus can we highlight and exacerbate to make this argument weaker?

Answer Anticipation:
The stimulus contains a potential fallacy of equivocation: there are real differences between chemistry and legal interpretation. Also, there's exactly one periodic table, whereas there are many different ordinary dictionaries that don't even always agree on Twitter, much less in the courtroom. Expect the correct answer to worsen the equivocation fallacy by confirming that there are big, important differences between these scenarios.

Answer Explanation:
Again we're highlighting a difference, but this time it's relevant to how people actually use the resources mentioned in the stimulus. If dictionaries' definitional differences affect how legal interpretation work is done, then legal interpretation could only be performed consistently if everyone used the same dictionary. And if they're haphazardly using whichever "ordinary dictionaries" they have on hand, that's unlikely to be the case.

Key Takeaway:
Analogies are only logically sound when the things being compared are similar in all respects relevant to the argument. Basing an argument on an invalid comparison is a fallacy of equivocation. This "apples to oranges" fallacy will come up in multiple question types, including Errors in Reasoning, Weaken, Strengthen, Necessary Assumption, Sufficient Assumption, Point at Issue, and more!

Incorrect. Yet a third answer cites a difference between dictionaries and the periodic table, but just like in A, the difference is irrelevant to the uses cited in the stimulus. The age of a resource isn't particularly relevant to the question of whether or not using that resource is justified.

Incorrect. Off topic! Nothing in the conclusion gives us reason to care about memorization. We only care about weakening the claim that using ordinary dictionaries for legal interpretation is "justified."

Incorrect. Probably the most tempting trap here, but if the use of ordinary dictionaries is otherwise justified, the fact that they're usually used for other purposes shouldn't matter. Lamps are primarily used for lighting, but that doesn't mean using a lamp as a paperweight is wrong.