Logical Reasoning

PT103 · S3 · Q8 Grasses and woody plants are planted

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Grasses and woody plants are planted on dirt embankments to keep the embankments from eroding.

Conclusion (Therefore)

Bringing in predators to eradicate rodents will prevent erosion of the embankments.

Evidence

Currently, we plant grasses and woody plants on dirt embankments to prevent erosion (the roots of those plants help protect against erosion).

But when we mow the grasses, the piles of clippings smother the plants, causing their roots to rot.

The clippings also attract rodents, who burrow into the dirt and damage the roots.

Evaluate

Since this argument is based around a Plan / Recommendation, we want to think about this plan could potentially fail to achieve its goal. The typical issues we consider are things like Feasibility, Motives/Incentives, Potential Backfire, and whether the plan targets Key Source of Problem.

How could we ... bring in predators that want to eat rodents, but ... this fails to prevent erosion?

What if the predators we brought in aren't able to catch and eat these rodents or don't seem interested in doing so? (feasibility / incentives)

What if the predators go after the rodents, but the predators themselves end up causing erosive damage? (backfire)

What if the damage to the roots from the rodents isn't nearly as important as the damage from the grass clippings that cause the roots to rot? (key source of problem)

Goal

Look for some way to object to this plan, to respond in a way that feels like,

8.

Which one of the following is an error of reasoning in the argument?

  1. Two events that merely co-occur

    Bad Conclusion Match Not Causal Flaw

    This answer refers to one of the 10 famous flaws, Causal Overconfidence, in which the author's conclusion is overconfidently assuming one causal explanation for why something has occurred / is occurring, when there are alternate explanations possible. This answer is specifically claiming that the argument presented a correlation between X and Y and then concluded that X causes Y. We can tell just by looking at the conclusion that this description doesn't match the argument. The author's conclusion isn't a causal explanation for something that's occurred / is occurring. It's a prediction. The prediction has a causal element to it (bringing in predators will cause erosion to be prevented), but the evidence didn't spotlight a correlation between predators and low-erosion. In fact, these predators don't even appear in the argument until the Conclusion.

    5% picked this

  2. A highly general proposal is

    Bad Conclusion Match Not Sampling

    This answer refers to one of the 10 famous flaws, Sampling, in which the argument relies on a sample that may be too small, biased, or unrepresentative. This argument doesn't rely on any move from a specific sampling of facts to a general proposal. Both the evidence and the conclusion are focused on the same issue, same scope, same facts. It's hard to call this conclusion a "highly general" conclusion. It's specifically calling for predators to be brought in to eradicate rodents in order to prevent erosion of certain embankments. And even if the facts we learned, about these embankments and their rodent problems, are not typical, it doesn't matter. The argument isn't claiming they are typical. It's just recommending a solution to this situation, whether it happens to be a typical or atypical situation.

    1% picked this

  3. The conclusion is no more

    Not Circular

    This answer refers to one of the 10 famous flaws, Circular Reasoning, in which the author's premise restates the conclusion or requires the conclusion to be true. These answers are almost always wrong. The conclusion clearly is not restating anything in the premise, given that the notion of "predators" only appears in the conclusion.

    1% picked this

  4. One possible solution to a

    Bad Conclusion Match

    This answer sounds a bit like the #1 famous flaws, Necessary vs. Sufficient, in which the argument presents a conditional logic premise but then illegally applies that rule in a backwards or negated fashion. Saying that "X would fix it, but X isn't required to fix it" is synonymous with saying "X is sufficient but not necessary". However, the easiest way to see this answer is wrong is just to check whether the author concludes that bringing in predators is the only solution to the problem. She does not. The conclusion just promises that it is a solution, not that it's a required solution. The latter would have sounded like, "Therefore, we will have to bring in predators to prevent erosion."

    5% picked this

  5. Correct

    An action that would eliminate

    Why this is right

    The problem we were trying to solve is the erosion of the embankments. We currently have grass and woody plants attempting to solve that problem. The roots of the plants are suppose to provide firm support to keep the embankment from crumbling due to erosion. However, roots are struggling: 1. when we mow, grass clippings suffocate the plants, which causes their roots to rot. 2. the grass clippings also attract rodents, whose burrowing activities damage the roots. The author presents a solution of "bring in predators to eradicate the rodents". While that will help with problem #2, it will do nothing to help with problem #1. Thus, it's true to say the author treats "bringing in predators", which only solves part of the problem, as though it will solve the entire problem of damaged roots / erosion prevention. (Maybe a better solution would be to rake up the grass clippings so that the plants can breathe and so that rodents aren't attracted to the area.)

    Skill tested: Flaw · how this choice captures the argument's function is the move to repeat next time.

    89% picked this

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