LSAT 41, Logical Reasoning II, Q12, LSATHacks

LR Question 12 Explanation, by LSATHacks

QUESTION TEXT: Yang: Yeast has long been known to be a leaven, that is…

QUESTION TYPE: Method of Reasoning

CONCLUSION: Yang concludes yeast was known to be a leaven in 1200 BC. Campisi is unconvinced.

REASONING: Yang bases his conclusion based on the fact that the bible mentions leavens as early as 1200 BC. Campisi points out there were other leavens besides yeast – meaning it’s by no means certain that ancient people knew yeast was a leaven.

ANALYSIS: Yang is making an unstated assumption: yeast was the only leaven known to biblical peoples. Therefore, if they knew about leavens, they must have known yeast was a leaven.

If other leavens also existed, the argument is no good.

___________

1. “I find your inference unconvincing.” Campisi is definitely not saying Yang’s conclusion is supported.
2. CORRECT. Presumption is another way of saying unstated assumption. Here Yang presumes that yeast was the only possible leaven.
3. Campisi considered the reason, and he found it unconvincing.
4. Campisi didn’t say what was true (“a contrary conclusion”); she only said that Yang was wrong.
5. Campisi didn’t disagree with Yang’s premises; she added to them, invalidating Yang’s conclusion.

Recap: The question begins with “Yang: Yeast has long been known to be a leaven, that is”. It is a Method of Reasoning question. Learn more about LSAT Method of Reasoning questions in our guide to LSAT Logical Reasoning question types.

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