A certain experimental fungicide

Answer choices

1. A

   Irrelevant: other methods8% picked this

   There is not an alternative method, besides application of this fungicide, for eliminating powdery mildew from rose plants

   This author didn't act like this fungicide is the only method that can do what the conclusion promises. So the author doesn't need to assume that there aren't other methods that could achieve the same outcomes. If we negate this and say, "there is an alternative method", it doesn't weaken at all. The author will just be like, "Cool -- I said this fungicide provides a means, not the only means".

   8%
2. B

   Out of Scope: risk to non-plants13% picked this

   When the fungicide is sufficiently diluted, it does not present any risk of harm to people,

   The conclusion is only promising that this method will involve no risk of harming the plants. She didn't promise no harm to people, animals, or insects. If we negate this and say "it does present some risk for people / animals / insects" we wouldn't be hurting anything she was arguing.

   13%
3. C

   Too Strong3% picked this

   Powdery mildew is the only fungal infection that affects

   Too Strong: the only Only Thing Mentioned ≠ Only Thing The only fungal infection afflicting rose plants that was mentioned in the paragraph was powdery mildew, but that doesn't mean that the author is assuming that powdery mildew is the only fungal affliction that afflicts rose plants. If I make an argument and San Francisco is the only Californian city I mention, that doesn't mean I'm assuming that "San Francisco is the only city in California".

   3%
4. D

   Too Strong13% picked this

   If a fungicide is to be effective against powdery mildew on rose plants, it must eliminate

   Too Strong: must Internal to a Premise There's no reason that the author has to define "effective" as "eliminating completely". The author just said, "this fungicide is so effective that it eliminates the powdery mildew completely." If we say, "He's so tall that he can dunk a basketball without jumping", does that mean we're assuming "If a person is to be considered tall, they must be able to dunk a basketball without jumping"? Of course not. We should be deeply suspicious of any Necessary Assumption answer that is trying to connect language from within one premise claim. This answer is just taking language from the 2nd sentence and trying to create a "missing link" out of it.

   13%
5. E

   Correct62% picked this

   The effectiveness of the fungicide does not depend on its being more concentrated than one part in

   Why this is right

   This has the lovable "ruling-out" not that is found in so many correct, Defender-style answers on Necessary Assumption. If we negate it, does it weaken? Can we object to the argument by saying that "the effectiveness of the fungicide does depend on its being more concentrated than one part in ten parts of water"? Yes! This gives us a way to argue that the fungicide, sufficiently diluted, won't provide a means of eliminating powdery mildew. Sure it's known to be effective against powdery mildew ... in its potent, concentrated form. But this negation is saying that once you water it down so that it's too diluted to harm the rose plant, then you no longer get its effectiveness at getting rid of the powdery mildew fungus. In essence, you can either choose to have this diluted enough to involve no risk of harming the rose plants, or you can choose to have this potent enough for it to eliminate powdery mildew. But you can't have both at the same time.

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

   62%