#9 - Paleontologists have discovered fossils of centipedes

[stephaniemaui]

Hi there,
I understand why AC D is correct, but I do not understand why AC B is incorrect.

My concern has been addressed earlier in this feed, but I felt as though the response was unhelpful! I am hoping you guys can help me with this dilemma!

My concern is with answer choice B. Just because all of the centipedes that had previously been discovered land dwellers, does not seem to strengthen the argument to me. It appears as invalid reasoning to me, similarly to other examples used in LR videos, we cannot conclude just because the sun rose yesterday that it will rise today.

I understand in the help family we accept the ACs as true, unlike family 1, but even when I accept B as true, I do not see how it strengthens the argument because it is faulty reasoning.

Should we never be concerned with validity in Help Family?

[James Finch]

Hi Stephanie,

Strengthen and Weaken stimuli are almost never 100% valid, even after a Strengthen answer is applied. Strengthening an argument is more about accumulating evidence in support of the conclusion (just a lawyer building a case would do), and weakening an argument is about supplying counter-evidence that undercuts a conclusion, neither of which are likely to be logically provable.

With that idea in mind, (B) does help a little bit (not as much as the other three incorrect answer choices, but still) by showing that all known centipedes have been land-dwelling. It's getting closer to the idea that being all centipedes are land dwelling, ie that being land-dwelling is a necessary condition of being a centipede. It doesn't get us all the way there, but it doesn't have to. Contrast this with (D), which is irrelevant to whether or not the centipedes found were land dwellers.

Hope this helps!

[stephaniemaui]

Thanks James! That does help, I must had been thinking that it had to justify the conclusion.

[Legalistic]

Hi, MThomp,

Answer choice (D) is tricky. It does bring up information relevant to the conclusion. The paleontologists conclude that the centipedes lived on land, even though the fossils were close to water-dwelling animal fossils.

What would happen to our conclusion if we knew that all the other early land dwelling animal fossils were found nowhere near water-animal fossils? Would we think it's more likely that the centipedes lived on land or less likely that the centipedes lived on land? If every other land dwelling animal fossil was nowhere near water-animal fossils, we would probably think it's less likely that these centipedes lived on land. After all, no other land animal fossil was near water animals.

Thus, this statement weakens the conclusion! It is an opposite answer. Since we are looking for the answer choice that is the least helpful to our argument, this one is it. It hurts our argument and does not help it at all, so it is the credited response.

I hope this helps!

Hello,

I still find it a little difficult to understand why D is the correct answer. Although I understand that it is a strengthen question, I can't help but think of how flawed D is. Assuming that because every other land dwelling animal fossil was nowhere near water-animal fossils, which then makes it less likely for centipedes to have lived on land as well seems to me like an error of division? Should I not be thinking about flaws at all in these types of questions? Can you please explain this again! I'm confused

[Jeremy Press]

Hi Legalistic,

You raise an interesting question about answer choice D! The error of division isn't applicable here, because we actually haven't been told anything in answer choice D about a "whole." Yes, we've been told about the (earliest) fossils of land dwelling animals that had previously been discovered. But that's a somewhat ill-defined group: have we discovered all such fossils? Do all such fossils represent all land-dwelling animals? We don't have a well-defined "whole" to extrapolate from here. So I wouldn't be worried about falling into an error of division in this case.

Now, I agree with you that I wouldn't want to conclude with certainty, based on answer choice D, that the fossilized centipedes were absolutely not land dwellers. However, if we can't identify a single fossil of a land animal that was found in a similar place as the fossilized centipede the stimulus discusses, then it does become more doubtful that this fossil is one of a land-dwelling animal. (Still not conclusive! Just less likely.)

Let me know if this helps!

Jeremy

[jdhd2798]

Hello,

I still don't understand how answer choice D can weaken the argument since the stimulus states that "the paleontologists are confident that the centipedes lived on land". How could answer choice D which states, "fossils of the earliest land-dwelling animals that had previously been identified were found in rock that did not contain fossilized remains of water-dwelling animals" weaken this argument? Doesn't it strengthen it?

[KelseyWoods]

Hi jd!

When you're strengthening or weakening arguments, it's important to identify the conclusion of the argument because that's what we're trying to strengthen or weaken. In this case, the question stem asks us to find something that would not strengthen the "paleontologists' view." So we need to identify what the view of the paleontologists is. The stimulus tells us that the "paleontologists are confident that these centipedes lived on land." That's their view, the view that we are being asked to NOT strengthen.

Answer choices (A), (B), (C), and (E) all strengthen their view that the centipedes lived on land. But answer choice (D) tells us that previously identified land-dwelling animals were not found in fossils with water-dwelling animals. This casts some doubt on the view that the centipedes were land-dwelling because they were found alongside water-dwelling animals.

Hope this helps!

Best,
Kelsey

[PavelN]

I read all of the explanation and I understand the reasoning behind answer D, however I fail to understand why it is the right one. The stem states - The view would be LEAST SUPPORTED BY... To support something means "to support in any way possible 1% - 100%". Answer D fails to support it in any way, meaning the effect of answer D on the stimulus is 0%. If the stem was worded like an EXCEPT question then I agree, D is correct. But since the question was put in a way that which answer supports to the lesser degree, in my opinion the correct answer should still support the stimulus.

[KelseyWoods]

Hi PavelN!

In general, you should treat "LEAST" question stems in the same way that you treat "EXCEPT" question stems--as the LSAT uses these terms in question stems they're basically just different wording variations of one another.

If something supports an argument by 0%, then that means it supports it less than an answer choice that might support it by 1%. NOT supporting an argument pretty much means that you support it the LEAST amount.

Think about a bunch of friends trying to move a couch. Some people might be bearing more of the weight of the couch than others. But if I'm just kinda walking beside everyone, not putting my hands on the couch, maybe even getting in the way of everyone else because I keep stopping in front of them to take selfies, I'm definitely the LEAST helpful friend.

The answer choices work the same way. If there's an answer choice that has no impact on the argument or even weakens the argument, it's definitely less helpful than any of the other answer choices which are helping out even a little.

Hope this helps!

Best,
Kelsey

[emilyjmyer]

Hi,

I am pretty confused with this question. I started out with a prephrase of needing to find something that would show that the centipedes could be water-dwelling or not land-dwelling. I chose C and I kind of understand the reasoning that it is not correct. But I do not see why D is correct. Why does it matter that earlier land-dwelling centipedes were not found with fossils of land-dwelling animals. Those ones are different came earlier. Maybe these ones that came later evolved? Thanks!