A distemper virus has caused two-thirds of the seal population in the North Sea to die since May 1988. The explanatio...

JonJay February 25, 2022

Rule for When It's Appropriate to Use Assumptions

Howdy, Like others on the message board, I narrowed this question down to (A) and (E). Both seemed really weak to begin with in terms of their capacity to strengthen the argument, but nonetheless, I chose what I thought was the least unappealing answer, (E). I understand the rationale provided in the answer explanation and clearly see that answer choice (E), if anything, would tend to weaken the argument as it provides an alternative explanation as to why the seal population cratered by 2/3rds. I have also gotten a few good sources of input from this message board, but one concern I have (that I would imagine is shared by others) involves assumptions within arguments. As I have gone through this course, a common theme of the teaching is to, in general, not include assumptions into your analysis of arguments when picking apart a stimulus and selecting an answer. Having said that, I can't help but observe that on both "Strengthen" and "Weaken" questions, many times assumptions are built into the argument and/or answer choices. Taking answer choice (A) for instance: "At various times during the last 10 years, several species of shellfish and seabirds in the North Sea have experienced unprecedentedly steep drops in population." In order to rationalize selecting this as "Strengthening the Argument" I have to assume that: (1) - The last 10 years is a relevant time window. The seal population referenced was in 1988 I believe, and it's currently 2022. So perhaps this question was created for an LSAT in 1998 in which case the 10 year window would make sense? (2) The pollution had the exact same impact on different classes of animals, in this case Shellfish and Seabirds, as it did on the seals, in spite of the fact that these are wildly different classes of animals. (3) "Steep Drops" has a ubiquitous definition and is comparable to the "2/3rds" loss of seal life in spite of the fact that it is not at all defined beyond the words "Steep" and "Drops". (4) "At various times" has an implied meaning of "not all the time". So there are times within a 10 year period where, at a minimum, we do not see a "steep drop" but perhaps only a "mild drop" (Again, loose definition, but hey) My point is not that I'm frustrated I got the answer wrong. I very clearly did. My point is that I have no reference point/guiding principle in the LSAT for when it is appropriate to make inferences in the stimulus and answer choices, and when it is inappropriate to do so. So to the end of improving my score, I am asking for some help in having, at a minimum, a loosely defined rule to help solve this problem. Thanks in advance, - JJI

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Emil-Kunkin March 11, 2022

Hi Jonjay,

I agree that A and E both look very weak- and that for strengthen and weaken it often feels like we are being asked to bake-in assumptions to our right answer choices.

I think there are two ways to approach this.

First- A is the least wrong answer. Without even getting into why A strengthens, we can see that b-d are clearly irrelevant at best, or even weaken.

That said, we do not need an answer choice that clearly strengthens. We only need one that could conceivably strengthen the reasoning. We do not need to establish the whole causal chain- only that the answer somehow makes the author's reasoning seem more plausible.

A tells us that there have been other seemingly random population declines. This supports the idea that "something" bad and sudden is happening in the north sea. Since pollution impacts entire ecosystems, it is a good candidate. That said, it is not the only good candidate. Perhaps algal blooms, weapons testing, or ghosts are the culprit. A does not prove the author is right, but it does lend credence to the idea that a pattern of similar events that is consistent with pollution has happened.

While weak- this is enough to (slightly) strengthen the argument without having to make any assumptions.