Logical reasoning PrepTest 145 · Section 2 · Question 14

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Errors in Reasoning

Stimulus Summary:
Problem Ð Cancer and birth defects
One cause Ð Water pollution, and the companies responsible won't stop
Solution Ð Lowering the incidence of the diseases requires halting these companies

Answer Anticipation:
This argument very much falls into the problem/solution structure, but there's an interesting wrinkle to it. There are actually two problems noted, one causing the other. The main problem that the argument is meant to address is certain medical conditions—the conclusion is about effective ways to lower their incidence. The other problem that is a cause of these conditions is the water pollution, and it's noted that the companies won't stop polluting on their own.

When an argument falls into the problem/solution structure, there's an important distinction that needs to be made in the conclusion. Does the argument conclude that a solution is a partial one—it'll address some of the problem—a sufficient one—it'll work, but it's not required—or a necessary one—it must be done? The former two types of conclusions aren't impacted by alternative solutions, but the latter one is.

Here, the Activist concludes that the solution presented—shutting down the polluting industries—is a necessary one. She states that "the only effective way" to lower the incidence of these conditions is to halt industries that are known polluters.

However, her premises don't back up that it's necessary to do so. While she does establish that the water pollution is a cause of these conditions, she doesn't establish they're the only (or even the primary) cause. As such, there could be other ways to lower the incidence of these conditions—addressing these other causes. In ignoring them, the argument is flawed, so the correct answer should point that out.

Answer Explanation:
This answer highlights that the argument treats addressing the industrial pollutants as a necessary part ("the only effective way") of lowering the incidence of water pollution when there may be other means by addressing other causes, so it's the correct answer.

Key Takeaway:
In an argument that falls into the problem/solution structure, be sure to note if the solution is stated to be partial or complete, and whether it's stated as being sufficient or necessary. Different answer choices will be correct depending on the answers to those questions.

Incorrect. The argument needs certain nonhuman species to ingest the toxins and then be consumed, moving those toxins up the food chain. They can be harmed by these toxins as long as this process can still happen.

Incorrect. Tempting answer, but this is actually the opposite of what we want. The argument assumes that the medical conditions are only caused by water pollutants, so it doesn't take for granted that effects have more than one cause.

Incorrect. The Activist does consider this—she says that it's unlikely they'll do so.

Incorrect. These pollutants are linked to certain medical conditions, so even if they have some other, beneficial effects, they still have this negative one that should be addressed.