LR Question 20 Explanation
QUESTION TEXT: The advent of chemical fertilizers led the farmers in…
QUESTION TYPE: Necessary Assumption
CONCLUSION: To improve the soil, farmers must stop using chemical fertilizers.
REASONING: Farmers started using chemical fertilizers, and stopped growing green-manure crops such as alfalfa. This harmed farms’ soil structure.
ANALYSIS: We’re conditioned to think chemicals are bad. But the argument didn’t say that chemical fertilizers hurt the soil. The argument said that the lack of alfalfa is what caused the poor soil structure.
Farmers might have stopped planting alfalfa because they thought they no longer needed it once they had fertilizer. But now that the damage is obvious, perhaps farmers could fix it by planting alfalfa again (without stopping fertilizer).
So the argument is assuming that farmers need to stop using chemical fertilizers before they can heal the soil with alfalfa.
___________
- The logic of this answer aside, negating a “most” statement is almost never significant. Moving from 51% to 50% is inconsequential in most situations apart from votes.
As for the logic of the answer: the argument is not assuming that if fertilizer goes away, the problem will be fixed (i.e. that lack of fertilizer is sufficient). Instead, the argument is assuming that lack of fertilizer is necessary.
Negation: Only half of the farmers who stop using chemical fertilizer will use alfalfa. - The point of the argument was that people stopped growing alfalfa entirely, after they began using chemical fertilizers. Farmers weren’t applying fertilizers to alfalfa.
- “The most important factor” is a reasonably common wrong answer. It almost never matters whether something is the most important factor.
For instance, you know the LSAT is an important factor in law school admissions. Do you care whether it’s the most important factor (rather than a close second, i.e. 51% vs. 49%)? - This would strengthen the argument, but it’s not necessary. The point of the argument was that farmers stopped using alfalfa once they started using fertilizer. The lack of alfalfa is the real problem.
- CORRECT. If many farmers may grow alfalfa again despite using chemical fertilizers, then it might not matter whether farmers still use chemicals.
Negation: Many farmers will grow green-manure crops even if they don’t stop using chemical fertilizers.
The issue I had with this question is the issue of need/facts. E just seems wrong to me because it’s more or less stating a fact, what farmers “will do” while the conclusion is arguing that something “needs” to be done in order to improve soil quality. I don’t understand how something that’s factual can weaken something about a need.