Whenever RC passages ask us about the author's argument, I have found it very helpful to do a quick prephrase of what the argument advanced in the passage was, even if I had no idea what the passage was about in detail -- as was the case with this passage. Here, the argument is essentially at a very, very high level: premise explaining why the legal decision was problematic -> conclusion that the legal decision was problematic.

Because this question is asking about the principle underlying the argument, the conclusion of the principle has to be that the legal decision was problematic. AC (D) is the only AC that matches the conclusion of the passage/author's argument.

I eliminated AC (A) for two reasons:

1. The chimpanzee may have evolved from an extinct diurnal species of lower primates, and thus from an organism other than the lemur.

2. The stimulus says that all higher primates are thought to have evolved from a single diurnal species of lower primates. This does not mean that they did in fact evolve from a single diurnal species of lower primates.

One thing I've noticed on the LSAT is the importance of distinguishing between what is thought to be true and what is actually true, so I think the second point is also worth noting.

Huh

I was tempted by AC (B) for different reasons from those mentioned in some of the other comments. I thought AC (B) could weaken the main conclusion because it says that most cases of OPV-caused polio occurred in a specific group of children, namely those who have "preexisting but unsuspected...disorders." So I thought, okay, that means the conclusion that we should switch from OPV to IPV "as the most commonly used polio vaccine for NA children" does not necessarily follow from the premises, because we could simply administer IPV to that specific group of children with preexisting disorders.

But this line of reasoning, and AC (B), actually does not weaken the argument because of the modifier "unsuspected" in the AC. Because the preexisting disorders are unsuspected, meaning that they are not known, doctors cannot selectively administer IPV to the specific group of children with those disorders. So the conclusion still follows even if AC (B) were true: it makes sense to make IPV the most commonly used vaccine rather than something selectively administered because we don't know which children have the preexisting disorders.

This reminds me that a single word in an AC can make it clearly wrong.

I was torn between AC (C) and AC (E).

I was initially drawn to AC (C) because of this text:

In 1996 he [Sibley] wrote that "Evolution produces all degrees of genetic differences between populations of organisms, but, for practical reasons, we must limit the number of degrees we choose to 'recognize' by names.

However, if we zoom out from what seems like supporting text for AC (C), we should remember that Sibley himself is a “splitter.” Splitters are those who “divide...populations into full species,” in contrast to “lumpers,” who “group separate but very similar populations of birds into a single species.” Just from the names of the groups themselves, lumpers would tend to lump populations together into fewer species, while splitters would tend to divide them into distinct species.

If we look at AC (C) from this perspective, AC (C) is no longer persuasive. Why would Sibley, a splitter who tends to divide populations into distinct species as opposed to lumpers, say that the goal is to reduce the total number of species?

Lmaoo that Fox comment is sending me

@ja4718b761 I think the two words will not be written the same, because I'd assume that dang-tang would be written in Chinese characters, not in alphabets. I thought dang-tang being italicized meant that it was meant to show pronunciation, whereas "downtown" being in quotation marks was intended to show how it is actually written... But yes, I was confused as well.

@bichonlua Oh now I get why AC D is right -- it's because the answer choice is framed as the phrase being "used to weaken the claim," rather than saying that the claim itself weakens the claim. I guess my studying is paying off...?

I've been confused about this question for a while, not because of the difficulty of the question itself, but because of AC B.

Wouldn't AC B weaken the argument rather than have no effect? Because we are showing that even without the purported cause (video game violence), we see the effect (aggressive behavior being acceptable) in some cases, wouldn't that weaken -- i.e., make the purported causal conclusion less plausible/likely to be true, albeit minimally?

I get that the conclusion is not saying that violence in video games is the ONLY cause, but even if that's not so, wouldn't showing that without the cause we still see the effect in some instances make the conclusion slightly less plausible/less likely to be true?

Or, thinking about it a different way: we know one way to weaken a phenomenon-hypothesis stimulus is to suggest an alternative hypothesis. In this argument too, the conclusion is not necessarily saying that the proposed hypothesis is the only explanation for the phenomenon, yet providing an alternative explanation weakens the conclusion because it makes it less likely to be true.

I'm confused as to why that logic applies in a phenomenon-hypothesis stimulus but not in this case with AC B..?

I debated btw AC B and E during timed session, but I think I've figured it out.

The reason I was hesitant to choose AC B was the phrase "not the CORE of a public official's job." I initially thought: even if making decisions about these matters is not the core of a public official's job -- and hence, say, a less important job than the core jobs/responsibilities of a public official -- they could still be jobs of a public official. However, given that the bar for weakening question is low, and that we just have to make it LESS PLAUSIBLE that biz execs are public officials, AC B works. For example, if we look at this argument:

• P: I make PPT decks for work.

• P (akin to the logic of AC B): Making decks is not the core of the job of a management consultant.

• => The conclusion that I am a management consultant is WEAKENED, as it has become LESS LIKELY or LESS PLAUSIBLE that I am a consultant, although it does not guarantee the falsity of the conclusion that I am a consultant.

For AC E, I was very tempted because I thought: if biz execs and public officials cooperate, doesn't that make it less likely that biz execs are public officials and hence weaken the conclusion? However, I think I was able to get rid of AC E for these two reasons:

1. AC E uses the word "often": it says that public officials and biz execs OFTEN cooperate, meaning they sometimes cooperate. But does this cooperation happen with matters discussed in the stimulus, such as making decisions about work org patterns, resource allocation, etc? We don't know.

2. AC E says execs and public officials cooperate in making decisions "of national importance." But again, do these decisions include or refer to the matters discussed in the stim? We don't know.

In sum, because AC E seems rather open to interpretation, we should eliminate it.

TLDR: My takeaways from this question:

• The bar for weakening is not high; weakening does not equate to guaranteeing the falsity of the conclusion.

• Always pay attention to modifiers that indicate frequency (e.g., "often" in AC E).

• Don't interpret an AC the way you wish it to be interpreted (e.g., don't assume "decisions of national importance" in AC E includes or refers to the decisions in the stimulus).

I didn't necessarily use a conditional diagram to solve this question. I thought the flaw in the stimulus was sort of similar to a flaw we're familiar with: just because the evidence against a claim is flawed does not mean that the claim itself is true (lack of evidence /= evidence of lack).

Here, the argument shows that Theresa disagrees with the disapproval most people have about the increase in income tax. The fact that she does not agree with this claim does not mean that she supports the conclusion these people draw (namely, disapproving of the prime minister's overall job performance).

With this in mind, I went into hunt mode to find a similar answer choice where one person disagrees with other people's opinion against a certain conclusion, and the argument concludes from this that the person agrees with the conclusion these other people disagree with = AC A.

I got this question right, but... how is AC C a valid argument? Isn't it conflating a "most" relationship with a causal relationship?

Just because most students who study pass their courses doesn't mean that it was studying that caused them to pass. I mean, yes, logically in real life this makes sense, but strictly from a logic perspective, isn't this not a valid argument?

For example, we cannot say:

Most people who study are diligent.

Therefore, studying "causes"/produces diligence.

Am I missing something? Help would be appreciated!

I chose AC C via POE, and was hesitant to choose it, especially because of the phrase "approval or disapproval of that character." But I chose the AC regardless of the reluctance, because it seemed to fit the bigger picture, and something I've realized in RC is that I should not eliminate an AC just because I am unsure of certain elements in the AC that seem to fit the big picture of the passage. I think this is especially the case because these uncertain elements would probably get support from the passage -- whether explicitly, very subtly, or even implicitly -- upon careful review.

During BR, I think I was able to find support for the phrase "approval or disapproval." The passage says in P1 that "the film is emblematic of Allen's career precisely because of its extravagantly exaggerated censure of a life dedicated to and obsessed with art." The fact that Allen's film censures a life dedicated to art implies that he is disapproving of that life. And therefore, I think it would be reasonable to assume that Allen would disapprove of his artist characters.

I'm confused by this question. Upon reading the stimulus, I identified two flaws:

1. (As JY mentions in the explanation video) Just because consumer cooperatives usually sell the same products more cheaply does not mean that shopping at a food co-op is more economical than doing so at a supermarket (the incorrect inference made from A->B-m->C)

2. The argument does not take into account other components that could make shopping "economical" besides the price of products.

   • For example, food co-ops might all be located in rural areas, so driving there might cost more in fuel, or they might have other cost factors on top of product price, like different sales tax.

I thought AC A especially mirrors the second flaw, because it concludes that those who own sports cars use more gasoline than those who own other types of cars on the grounds that sports cars use more gasoline PER MILE. As JY mentions, the conclusion seems to ignore other factors, like the fact that the distance sports car owners tend to drive might be greater.

Given this, I thought AC A and AC C both tackle different flaws present in the stimulus. And since none of the other ACs seem to tackle both flaws, and neither A nor C contains the other flaw in the stimulus, I was unsure how to decide between AC A and AC C.

In the explanation video, JY diagrams "more economical to shop at a food co-op" as meaning the same thing as "offering the same products usually more cheaply." But isn't this making an assumption? Why aren't we treating this as a flaw?

I figured this out during blind review, but only after spending several minutes trying to identify the paradox... What should I do when I run into questions that, for some reason, I can't grasp under timed pressure? D:

@Adam Thank you sm -- this was extremely helpful!

@AriVilker1 Thank you sm -- this was very helpful!

I was between AC A and B during the timed section. I was tempted by AC A because:

1. By showing that subsequent experiments yielded the same correlation between paying more attention and perfect intervals, it seemed to increase the plausibility of the conclusion.

2. Because I saw a jump from premise to conclusion (the premise talks about babies while the conclusion talks about humans), I thought bridging this scope gap would strengthen the argument.

However, I think AC A is wrong for these two reasons:

1. As JY mentions in the video, children and adults would be even more susceptible to cultural influence, which constitutes an alternative explanation for why humans pay more attention to perfect intervals.

2. AC A confirms a correlation, but the conclusion is trying to establish a causal mechanism: biological predisposition -> paying more attention to perfect intervals. This AC therefore does not confirm the causal link but merely reaffirms the correlation. While reaffirming a correlation does help, a stronger AC would be one that shows how the experiments established the causal mechanism.

While the second point is less of a direct way to eliminate the AC, I think it's also something to keep in mind for harder questions with multiple challenging contender ACs.

Just wanted to share how I arrived at the right answer, even if the reasoning may not be perfect -- pls feel free to disagree.

Thought AC B is correct for the following reasons:

• 1) The passage says in P2: "Instead of dating fault-line sediments, lichenometry involves measuring the size of lichens growing..." "Instead of dating fault-line sediments" implies that radiocarbon dating, unlike lichenometry, involves dating fault-line sediments.

• 2) Now, I know that the first sentence of P1 says: "...seismologists usually dig trenches along visible fault lines" and that "usually" does not mean "always." However, this sentence is saying that seismologists usually dig trenches along VISIBLE fault lines, not all fault lines. If we combine #1 above with this fact, I think we can reasonably deduce that radiocarbon dating requires fault lines.

• 3) AC B says "unlikely," which does not mean 100% absolutely. I think this slightly weakens AC B.

Thought AC E is wrong for the following reasons:

• 1) This AC is basically saying that the usefulness of lichenometry is ONLY present in regions where those factors generally don't occur. But the passage never actually RESTRICTS the usefulness of lichenometry. In fact, if you read the last sentence of P3, it says "sites must be selected to MINIMIZE the influence of snow avalanches and other disturbances." This is different from saying that sites must be selected where there is NO influence of avalanches and other disturbances.

• 2) Compared with AC B, I think AC E expresses a stronger claim because AC B says that something is unlikely, whereas AC E says that usefulness is limited to -- which is a complete restriction. Since this is an MSS question, I think AC B is easier to support, although it may not do so perfectly like a MBT.

@jrrphd This was incredibly helpful -- thank you!

@SCOTT_LEBO This was extremely helpful -- thank you so much!!

@cgmahoney2 I also chose AC B for the same reason after debating between AC B and C. Would really appreciate if anyone could help shed light on this!

Could this be seen as argument by analogy and the correct AC pointing out to a potential difference between Sullivan and his colleagues that the argument overlooked and hence weakens the analogy?