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#18 - A large survey of scientists found that almost all

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Please post below with any questions!
Tranquility
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I'm stuck between A and B, though I'm not 100% sure that those are the 2 best options. My logic for choosing B included negating B so that is read "The scientists in the survey who know the results of the Brown-Eisler Experiment are not exactly the same ones who accept Wang Law," which seems to slightly weaken the conclusion. I also diagrammed the stimulus and got:
scientists (Most)---> (Accept Wangs Law + Know Brown Eisler) ---> contradict Minsk Hypothesis


The diagram didn't clear up the confusion much--is it correct?
Thanks for clarification.
Jonathan Evans
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Hi, Tranquility,

You're on the right track, but remember, the Assumption Negation test means that you have to consider whether it is even possible for the conclusion to be valid given that the information in the answer choice is negated. In other words, the logic behind an assumption problem looks like this:

    Valid Conclusion :arrow: Information in Credited Response True

The Assumption Negation test uses the contrapositive of this construction:

    Information in Credited Response False :arrow: Invalid Conclusion

Even if you can somehow weaken the claim with a negated answer choice, this is not sufficient to know that you have a correct answer. You must ask yourself whether it is even possible that the conclusion be valid given the negated answer choice. If the conclusion is still possibly valid, then you have an incorrect answer.

Notice also the strength of language in Answer Choice (B) ("exactly the same ones as"). It is unlikely (though not impossible) that the credited response to an Assumption question will use such a powerful, "extreme" statement because it is unlikely that such a strong statement is necessarily true.

In contrast, Answer Choice (A) is undoubtedly necessary for the conclusion to be valid. If the scientists surveyed are not generally aware (safe to read as "less than half") that the combination of the two premises contradicts the Minsk Hypothesis, then the conclusion that most of the scientists surveyed reject the Minsk Hypothesis is both unfounded and invalid.
Iri
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Hello,

I don't understand the answer to number 18 of section one of LSAT 79. I put down B rather than A. Would someone be able to explain? Thank you!
Adam Tyson
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Hey there Iri, thanks for asking. Did you read Jonathan's explanation about those two answers just before your post in this thread? Look it over and let us know if you need further explanation. Tell us where you are getting hung up and what it is about answer A that is appealing to you over answer B. In particular, did you apply the Assumption Negation TechniqueTM to both answer choices to assess their impacts?

Looking forward to hearing your response, and I hope what we have already said here helps!
Adam M. Tyson
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Iri
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Ah okay, I understand. Thank you! While B could weaken the argument, it is the wording "exact" that restricts the answer to be too restrictive. Right?
Kristina Moen
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Iri,

Yes, an Assumption questions asks for something that is required by the argument. The word "exact" in answer choice (B) means that every single scientist who knows B-E is one who accept Wang's law. Using the Assumption Negation Technique - if just one person who knew B-E did not accept Wang's law, would that kill the conclusion? No, since the conclusion is that "most" of the scientists surveys reject the Minsk Hypothesis.
erust2
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I saw this a little differently. The stimulus says the scientists “know the results” of the B-E experiment. It didn’t say that they “agreed” with the results. So, I prephrased something to the effect of the scientists agreeing with the results. They have to agree with the results in order for the conclusion to be properly drawn.

Even though (A) didn’t match my prephrase, it seemed most relevant.

Was this a wrong way to get to the correct answer?
Francis O'Rourke
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Hi Erust,

I would agree that the connection between 'knowing of' and 'agreeing with' or 'accepting' the results of the B-E experiment is a necessary assumption that the speaker is making. If a hypothetical answer choice (F) were present and stated "many scientists who know the B-E experiment's results do not dispute those results," than that would have been a valid answer choice.

Where you went wrong was expecting being too specific or narrow with your prephrase. Since there are sometimes hundreds of possible necessary assumptions that an author is making, you can't get too stuck on a specific prephrase. The existence of another necessary assumption doesn't make your anticipated necessary assumption any less necessary.

Similarly, just because you found a gap in the author's argument, that does not mean that there is no other gap. Answer choice (A) is still something the author must necessarily believe. It sounds like you chose this one because the wording or scope was most similar to what you expected. After getting the chance to review it, do you understand why answer choice (A) is necessary for the speaker's argument?
erust2
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Thanks so much. I do, for the most part, understand why A is correct. I just don’t love it. I think it’s the engineer in me that I wanted to see something that’s said they agreed with the results.

On a side note....I am doing better then I expected on the LR sections, but I seem to get several questions correct by process of elimination. I’m definitely not complaining. But, is this normal/expected?