Summary
Dooney County isn’t flat. How do we know? The author sets up a conditional argument with two key premises:
(1) If farmland is flat, then farmers don’t build terraces to prevent erosion on that land.
(2) In Dooney County, there are terraces on farmland (at least, so the author hears).
(1) If farmland is flat, then farmers don’t build terraces to prevent erosion on that land.
(2) In Dooney County, there are terraces on farmland (at least, so the author hears).
Notable Assumptions
The author tries to use premise (2) to trigger the contrapositive of premise (1). But he relies on several assumptions to make that contrapositive work:
- What he’s heard about terraces on Dooney County’s farms is true. (Otherwise, there’s no reason to think there are any terraces.)
- Some terraces in Dooney County were built to prevent erosion. (If they were for another purpose, they tell us nothing about whether the land is flat.)
- Some terraces in Dooney County were built by farmers. (If other people built them all, we can’t infer anything about the land.)
A
the only cause of soil erosion is water
It’s the presence of terraces, not the specifics of erosion, that the argument depends on. Even if other causes of erosion exist, we know that on flat land, water-caused erosion isn’t a problem, and so any time farmland is flat, farmers won’t build terraces to prevent erosion.
B
there are terraces on farmland in Dooney County which were built to prevent soil erosion
This must be true for the author to infer that Dooney County is not flat. If (B) weren’t true—if there are no terraces that were specifically built to prevent soil erosion—then whatever terraces are there tell us nothing about whether the land is flat.
C
terraces of the kind found on farmland in Dooney County have been shown to prevent soil erosion
Whether the terraces happen to prevent erosion is irrelevant. What matters is what the terraces were built to do. For the argument to work, the terraces must have been specifically built (by farmers) to prevent erosion. Otherwise, the presence of terraces means nothing.
D
on flat land there is no soil erosion
It’s the presence of terraces, not the specifics of erosion, that the argument depends on. Even if erosion occurs on flat land, we know that water-caused erosion isn’t a problem, and so any time farmland is flat, farmers won’t build terraces to prevent erosion.
E
the only terraces in Dooney County are on farmland
Too strong. The argument only requires that at least some terraces in Dooney County are on farmland (because it’s the presence of farmland terraces that can help tell us whether the land is flat). Whether or not terraces also exist on other kinds of land is irrelevant.
Summarize Argument: Counter-Position
The author argues that the political commentators’ assessment is mistaken, because most people disagree with them.
Identify and Describe Flaw
This is the cookie-cutter “fact vs. belief” flaw, where the author incorrectly assumes that because a group of people believe something to be true, it must be a factual reality. In short, she claims, “Most people believe X. Therefore, X is true.”
A
the term “policies” is used ambiguously in the argument
This is the cookie-cutter flaw of “equivocation,” where the author uses one term to mean multiple different things. But the other uses “policies” consistently, so (A) doesn’t describe the flaw in her argument.
B
the political commentators discussed in the passage are not identified
The fact that the commentators are not identified does not change their assessment or affect the author’s argument. So (B) cannot be the flaw.
C
a claim is inferred to be false merely because a majority of people believe it to be false
The commentators’ assessment is inferred to be false merely because “most people disagree” with it, or believe it to be false. But just because most people believe something, is not evidence that it is actually the case.
D
the claim that the political commentators are mistaken is both a premise and a conclusion in the argument
This is the cookie-cutter flaw of “circular reasoning,” where the premise is simply a restatement of the conclusion. But the claim noted in (D) is only the conclusion. The author’s premise and conclusion are distinct in this argument, so she doesn’t make this mistake.
E
it is assumed that what is true of persons individually is true of a country as a whole
This is the cookie-cutter “part vs. whole” flaw. But this doesn’t apply to this argument at all. The author never assumes that what is true of one part of the country is also true of the country as a whole.
"Surprising" Phenomenon
Alfalfa increases the nitrogen in the soil, yet it struggles when planted in the same field year after year.
Objective
A hypothesis explaining this similarity must imply that alfalfa will struggle when planted in successive years. This may be a consequence of increased nitrogen in the soil, or it may be unrelated to nitrogen.
A
Some kinds of plants grow more rapidly and are more productive when they are grown among other kinds of plants rather than being grown only among plants of their own kind.
It is not stated whether alfalfa is one such plant, nor is it stated whether alfalfa is typically mixed with other crops. This does not address the success of crops that are planted in the same field in successive years.
B
Alfalfa increases the amount of nitrogen in the soil by taking nitrogen from the air and releasing it in a form that is usable by most kinds of plants.
This simply describes the mechanism by which alfalfa increases nitrogen in the soil. It does not explain why alfalfa struggles when planted in successive years.
C
Certain types of plants, including alfalfa, produce substances that accumulate in the soil and that are toxic to the plants that produce those substances.
This explains why alfalfa struggles when planted in successive years. Though the soil accumulates nitrogen, it also accumulates toxic substances that are detrimental to alfalfa’s health.
D
Alfalfa increases nitrogen in the soil in which it grows only if a certain type of soil bacteria is present in the soil.
This does not state whether the required bacteria exists in alfalfa fields. It establishes a condition necessary for alfalfa to be nitrogen-fixing but takes no position on whether that condition is satisfied.
E
Alfalfa is very sensitive to juglone, a compound that is exuded from the leaves of black walnut trees.
This information is useless without more context. No given information suggests that black walnut leaves will more likely be present in fields where alfalfa is grown in successive years.
Clinic administrator: But the successful development of new technologies will allow early diagnosis of many neurological disorders. In most cases, patients who are treated in the early stages of neurological disorders suffer far less than do patients who are not treated until their neurological disorders reach advanced stages.
Speaker 1 Summary
The hospital auditor argues that the clinic is not using all of the donated funds to minimize patients’ suffering, contrary to the terms of the donation. Why not? The clinic is using a portion of the money to research new diagnostic technology. The auditor presumably believes that this does not help to minimize suffering.
Speaker 2 Summary
The clinic administrator leads us to the implied conclusion that these research funds are helping to minimize suffering. How so? Because new technologies will allow early diagnosis of some disorders, and patients who are treated early usually suffer much less than patients who are treated later.
Objective
We’re looking for a disagreement between the speakers. They disagree about whether the clinic’s use of donated funds is meeting the requirement to minimize suffering.
A
whether early treatment of many neurological disorders lessens the suffering associated with those disorders rather than completely eliminating such suffering
Neither speaker discusses this claim. Even the clinic administrator, who talks about early treatment reducing suffering, never specifies whether the reduction is partial or whether it can eliminate suffering.
B
whether the patients being treated at the neurological clinic are currently receiving adequate treatment for the neurological disorders from which they suffer
Neither speaker talks about this point. The auditor and administrator are arguing about the use of donated funds, not about the actual quality of care patients are currently receiving.
C
whether the Rodríguez family clearly stipulated that the funds they donated to the neurological clinic be used to minimize patients’ suffering
The hospital auditor agrees that this is the case, but the clinic administrator never disagrees. The administrator doesn’t directly say anything about the terms of the donation.
D
whether the neurological clinic is adhering strictly to the conditions the Rodríguez family placed on the allocation of the funds they donated to the clinic
The auditor thinks that this is not true, while the administrator thinks that it is: this is the disagreement. The auditor explicitly states that the clinic is violating the conditions. The administrator, though, explains how the clinic is actually using the money as required.
E
whether the Rodríguez family anticipated that some of the funds they donated to the neurological clinic would be used to pay for research into new diagnostic technologies
Neither speaker makes this claim. Neither the hospital auditor nor the clinic administrator says anything about the specific ways that the Rodríguez family expected the money to be used.