Logical reasoning PrepTest 149 · Section 1 · Question 21

Incorrect. The value of the tools doesn't speak to what purposes they were used for.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Strengthen with Necessary Premise

Stimulus Summary:
A: We found 5,000-year-old copper tools in an area that had use for canoes and had the materials to build these canoes. Aboriginal people currently in the area make canoes. Therefore, it's likely Aboriginal people built these canoes 5,000 years ago.

Answer Anticipation:
Whenever an argument starts talking about different time periods, you should start to suspect that it's doing so in a flawed manner. This specific type of comparison generally breaks down because the argument assumes that there have been no relevant changes in the intervening years. Especially when the jump is 5,000 years, that seems like a questionable assumption.

Here, the argument is basing a conclusion on what happened 5,000 years ago based on tools found in an area today, and practices by a group today. If there's any reason to question whether either of those things applied a few millennia ago (e.g., the Aboriginal people moved into the area only 3,000 years ago, or the tools were washed to this area from far away by the river), then the argument falls apart. Therefore, we need to find an answer that eliminates these potential differences between the time periods to justify a conclusion relying on a similarity between them.

Answer Explanation:
This answer highlights that the tools found by the river today were in the area 5,000 years ago—and thus can serve as evidence for practices done in that time period. If they weren't present in the region 5,000 years ago—they were brought there during a later move, or washed into the area from far away by the river—then they don't support a conclusion about that time period. This answer is necessary for the argument to work, so it's correct.

Key Takeaway:
When an argument jumps between time periods—whether it be 5,000 years or a week—the argument is assuming that these time periods are relevantly similar. As such, answers that establish similarities or differences can affect the argument.

Incorrect. As long as they could be used on material from those trees, it doesn't matter if they were designed to do so or that they were designed exclusively to do so. The argument only needs these tools to be effective, not exclusive.

Incorrect. Even if other tools were also used to make canoes, if these tools were used for that purpose as well, the argument can still work.

Incorrect. Even if the tools have other uses, as long as they're also used to make canoes, the argument can still work.