Logical Reasoning

PT128 · S2 · Q3 Agriculture researcher: Because of its slow

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Agriculture researcher: Because of its slow decomposition, paper is ineffective as a mulch to guard against soil erosion.

Conclusion

Farmers would be better off using the mix of paper and manure than using paper or manure alone.

Evidence

Paper is ineffective as a mulch to guard against soil erosion, but paper and manure is very effective.

In test plots, the mixture significantly decreased the amount of soil erosion.

And paper costs roughly the same as manure.

Evaluate

In order to argue against this conclusion, we have to try to argue that farmers would be better off "just using paper" or "just using manure".

The argument does a decent job of talking us out of "just using paper'". After all, paper is super ineffective at guarding against soil erosion.

But we never hear anything about the "just use manure" option. We know that the paper/manure mix is very effective, but maybe "just manure" is even more effective.

We're not saving any money by adding paper to manure (since they cost roughly the same), so what's the benefit of adding paper? Why not just use manure.

Goal

To complete this question stem with something like our objection, we'd say that the author provides no evidence that .

provides no evidence that X is the same as takes for granted that X presumes, without providing justification that X fails to establish X

The top one is very uncommon, but those bottom three all mean "the argument had to assume X", so we can read these answer choices as though we're doing Necessary Assumption.

3.

The agriculture researcher's argument is flawed because it provides no evidence that

  1. paper by itself does not

    Not as Strong an Objection

    If paper by itself does contribute to soil erosion, does that weaken the argument? Yeah, a little bit. It would again make us wonder whether we'd be better off just using manure alone. It would strengthen the idea that paper/manure mix is better than paper alone, though, so it's weird to talk about its impact. It strengthens half the conclusion and weakens half the conclusion. The weakening effect of this negation is not as strong as that of the correct answer.

    3% picked this

  2. mulch containing paper and manure

    Contradicted: Did Not Provide Evidence

    We explicitly got evidence that mulch with only paper is ineffective, whereas mulch containing paper and manure is very effective.

    4% picked this

  3. Correct

    mulch containing paper and manure

    Why this is right

    This was the missing comparison we spotted. If we negated this answer, it would say "mulch with a mix of paper/manure does not work better than mulch with manure alone", which would weaken so much it would essentially contradict the conclusion.

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

    84% picked this

  4. mulch containing paper and manure

    Out of Scope: other methods

    The conclusion isn't saying that farmers would be better off with this manure/paper mixture than they would with any other method of preventing soil erosion. It's only claiming that the manure/paper mixture is better than paper alone or manure alone, so the author isn't making any assumptions about any other methods besides the three options being compared in the conclusion.

    7% picked this

  5. mulch of pure manure provides

    Weakens

    The author would not want to provide evidence of this, since this would directly weaken her conclusion. This makes it sound like manure-alone might be better than a manure/paper mix.

    2% picked this

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