Logical Reasoning

PT111 · S4 · Q20 Archaeologist: A skeleton of a

A free, expert breakdown of this official LSAT Logical Reasoning question.

Save & drill this skill — build targeted practice sets from questions like this one
Video walkthroughs — watch every question solved step by step
81 official LSATs — as questions, timed sections & full-length tests

Archaeologist: A skeleton of a North American mastodon that became extinct at the peak of the Ice Age was recently discovered.

Conclusion

The first Eurasian settlers in North America probably came from a more distant part of Eurasia.

Evidence

We found a mastodon, which went extinct at the peak of the Ice Age, with a human-made projectile in it. The projectile wasn't like anything we've ever seen from the part of Eurasia closest to North America.

Eurasians didn't settle in North America until shortly before the peak of the Ice Age.

Evaluate

This is a somewhat confusing case being made, so we should take our time to understand how the timelines are meant to work.

This mastodon we found must have lived before the peak of the Ice Age, because by the peak the mastodon species had gone extinct.

The first Eurasian settlers didn't arrive in North America until shortly before the peak of the Ice Age (so there were probably still some mastodons left; they hadn't yet gone fully extinct).

Those two pieces of evidence are meant to establish that Eurasians had an opportunity to be on North America while there were still mastodons present, but barely.

For the author, that increases the likelihood that whatever projectile we find in a mastodon was probably put there by some of the first Eurasian settlers. That's where that New Term in the conclusion is coming from.

In terms of the other New Term in the conclusion, a more distant part of Eurasia, this comes from a couple assumptions the author is making: 1. If it's a human-made projectile, it's gotta be from a Eurasian human settler (she's failing to consider that it might come from humans already indigenous to North America)

2. If it's a projectile we dissimilar to any we've found in nearer-Eurasia, then it must have home from more distant-Eurasia. (she's failing to consider that maybe it's still from nearer-Eurasians, and this just happens to be the first found artifact of its type)

Goal

Since the author is explaining a Curious Fact (where did this strange human projectile come from?) by saying "it probably came from distant-Eurasians", we can weaken her argument by ...

suggesting an Alternate Explanation for the projectile undermining the plausibility of the hypothesis that it came from distant Eurasia

But in addition to the Curious Fact / Explanation thing going on here, the author is also committing to the idea that not only is this weird projectile from distant-Eurasians but that those distant-Eurasians were the first Eurasians to settle in North America. So we could also weaken the argument by calling that notion into doubt.

20.

Which one of the following, if true, most seriously weakens the archaeologist's argument?

Correct
The projectile found in the
Why this is right
This badly undermines the plausibility of the author's explanation for the projectile. She was thinking, "Since it doesn't look like a projectile from close-Eurasia, it must have come from distant-Eurasia". She was assuming that maybe that type of projectile is found in distant-Eurasia. This answer is saying, "Nope." Since the projectile doesn't resemble anything we've found from all of Eurasia, the author's hypothesis is badly weakened, and anyone who wanted to argue, "Maybe this is from an indigenous North American" would have his argument starting to look better and better.
Skill tested: Weaken · how this choice captures the argument's function is the move to repeat next time.
63% picked this
The people who occupied the
Strengthens, if anything
If the close-Eurasians remained nomadic throughout the Ice Age, then they didn't settle anywhere! That makes it more likely that distant-Eurasians would have had to be the first Eurasian settlers.
19% picked this
The skeleton of a bear
No Impact
This just adds more evidence that humans were hunting big animals with these projectiles, but this answer doesn't help us assess the central Causal Mystery: who were these humans? where did they come from?
3% picked this
Other North American artifacts from
Strengthens, if anything
This either does nothing, or it slightly helps the author to build plausibility that there were in fact distant-Eurasians leaving behind artifacts in North America.
7% picked this
Climatic conditions in North America
Less Impactful Than The Answer
This establishes some incentive for people from close-Eurasia to come settle North America, in the time period before the Ice Age. So it helps weaken the conclusion somewhat, because we can argue, "The first Eurasian settlers weren't from distant-Eurasia. They were from close Eurasia, since those people had incentive to come to a better climate in North America." However, 1. people in distant Eurasia may have had the exact same incentive 2. a more habitable climate is not a strong incentive for a migration (migrations are tough activities driven by necessity, not improvement). Los Angeles is more conducive to human habitation than is Detroit, but that doesn't mean we see a huge tide of people leaving Detroit for LA. Moving is complicated. 3. this answer weakens in a very diffuse way -- "Oh? Maybe people in close-Eurasia would have wanted to come settle North America" (not that they would know the climate in North America, prior to arriving). The correct answer weakened in a much more definitive way --- "This projectile probably isn't Eurasian at all."
8% picked this

Continue the review in LSAT Lab

Save this question, watch the video walkthrough, and drill similar questions in your LSAT Lab account.

Save and practice this skill

LSAT Lab

Turn this review into a targeted study plan.

Save this question, drill more like it, watch the video walkthrough, and track your progress in your LSAT Lab account.

Start practicing free