#12 - Yang: Yeast has long been known to be a leaven, that

[Administrator]

Complete Question Explanation

Method of Reasoning. The correct answer choice is (B)

In this dialogue, Yang presents a rather unconvincing argument: Since biblical evidence shows the use of leavening back in 1200 B.C., Yang concludes that yeast was known to be a leaven during that era. Campisi questions this conclusion, pointing out that there could have been other leavens used during that era.

The question requires that we find the answer choice which best describes Campisi’s counter to Yang. Correct answer choice (B) describes Campisi’s method: the underlying presumption which Campisi questions is Yang’s assumption that if leavening was used in 1200 B.C., it must have been yeast which was used.

Answer choice (A) is incorrect, because Campisi provides no suggestion to support Yang’s conclusion, and no other evidence either. Answer choice (C) is incorrect, because Yang’s reasoning is considered, and then the conclusion was questioned. Answer choice (D) is wrong because Yang’s evidence would not support the contrary conclusion—that is, there would be no reason to conclude, based on Yang’s evidence, that they definitely didn’t know about yeast in 1200 B.C. Answer choice (E) is incorrect, because Campisi does not question Yang’s evidence—only Yang’s underlying presumption and thus, Yang’s conclusion.

[emilyjmyer]

Hi!

So with this question I picked answer choice C because I thought that Campisi was questioning Yang's conclusion.
Isn't the conclusion that yeast was already known to be a leaven at the time? and then, Campisi says another leaven other than yeast could have been known at the time. Thus, questioning yang's conclusion. So, I picked C because Campisi denies the truth of Yang's conclusion. I am confused by B because it says that Campisi questions the truth of a presumption underlying the conclusion/argument. Wouldn't that mean that Campisi is questioning the evidence?

Thanks!

[Robert Carroll]

emily,

Answer choice (C) does not say that Campisi is questioning Yang's conclusion - it says that Campisi denies the truth of Yang's conclusion. Yang's conclusion is that yeast was known to be a leaven in 1200 BC. Campisi nowhere says that yeast was not known to be a leaven at that time. Campisi brings up an alternative explanation that could show Yang to be wrong, but note how even Campisi states it: "could have been known." Saying that something else might be going on is not the same as saying something else is going on. Thus, the "denying" language of answer choice (C) is incorrect.

This highlights why it's so important to pay careful attention to the actual language of the answer choice. If answer choice (C) had said "questioning", that sounds great! Questioning is very different from denying or contradicting.

Answer choice (C) also has a further problem in that it says that Campisi doesn't consider the reason Yang gave for his conclusion. That's just not correct - Campisi is directly saying that the evidence from 1200 BC may point to a different leaven. So the evidence is considered, which is an additional problem with answer choice (C).

Campisi is questioning the evidence - not the stated evidence, but the assumption that showing that leavens were known automatically proves that yeast specifically was known. Yang's argument assumes that - thus, it's not stated directly as evidence, but is an assumption underlying the argument. And note how answer choice (B) has the "questioning" language that we wanted answer choice (C) to have! If that's a good thing about answer choice (B), it's a bad thing answer choice (C) lacks it.

Robert Carroll

[marioncarroll]

Hello! I got this question right but it led to me to realize I don't really know the difference between assume and presume. I've watched several YouTube videos explaining the difference but I wonder if someone would be able to provide me with an explanation that better suits the LSAT world? I just get a little nervous when I see "presume" and think that I treat it the same as "assume" so in case a question arises that relies on understanding this distinction I'd love to be better armed for it. Thank you in advance!

[Luke Haqq]

Hi marioncarroll!

Though the word presume appears here and there on the LSAT, it's more common for the test to use the word assume, especially in question stems.

If you happen to encounter the less frequent situation in which presume is used in a question stem rather than assume, you should treat them as interchangeable. That means that you should treat it like an assumption question type. That should hopefully remind you to categorize it as similar to other helper question types, namely, strengthen and justify questions. Assumptions are necessary for a conclusion to follow, strengthen answers help the conclusion in any amount, and justify answers are overwhelmingly sufficient for a conclusion to follow. It should also hopefully remind you to apply the Assumption Negation technique, which can help you confirm the right answer.