I have a question regarding #20. I picked the right answer A because I recognized it as a flaw that was present in the argument- but I was wondering if you could elaborate why B was incorrect. Even though I did not choose it, I want to be able to understand for future questions why this was an incorrect answer.
#20- A study of rabbits in the 1940s convinced many
In Question 20 of O08, we have a classic error in the use of evidence: lack of evidence for a position (we haven't been able to prove that parthenogenesis occurs in mammals) is taken to prove that position is false (parthenogenesis does not occur in mammals). Answer choice (A) correctly describes this error, and is therefore correct.
Answer choice (B), by contrast, describes an entirely different error of composition, which occurs when the author attributes a characteristic of part of the group to the group as a whole or to each member of the group. In this particular argument, the author does not infer that parthenogenesis is shared by all nonmammalian vertebrate species. In fact, the conclusion has nothing to do with nonmammalian species at all: the author is only concerned with whether or not parthenogenesis can occur in mammals, and - if not - why.
Hope this helps! Let me know.
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That was very helpful- Thank you.
So I was really torn between A and C. I ended up picking C.
My reasoning for this was because the conclusion states "there must be SOMETHING about mammalian chromosomes that precludes the possibility of parthenogenesis. And C states: "there is another explanations that can account for the phenomenon. That was the reason why I picked C. But I guess that C is incorrect because even though the author mentions that "something" its not a definitive statement to rule out another possibility.
The author never says that there is another explanation that can account for the phenomenon just that there is something else?
I'm actually not sure I follow your reasoning here. Can you take answer C and replace "an explanation of a phenomenon" with something specific from the stimulus (i.e., what the explanation is and what the phenomenon is), and then also tell me what you think the "another explanation" would be? That will help us understand what your thought process was with C so we can explain why C is wrong.
I picked C as answer rules out explanation (no other studies have succeeded in demonstrating mammalian parthenogenesis) of phenomenon (Reproduction without fertilization of egg, sometimes occurs in mammals) on the grounds that there is another explanation (there must be something about mammalian chromosomes that precludes the possibility of parthenogenesis).
But in my paraphase, I included 1) study methods flawed (error in study methods) and no studies succeeded in demonstrating (not R-> FE) (no proof to validate that condition exists) and 2) presents known occurrence in nonmammalian vertebrates, there must be something about mammalian chromosome that precludes the possibility.
Oh, I see now that because the authors presents a known occurrence (not fact) then I can not really draw the conclusion there must be something else. Is that right?
So I'm left with 1) which bases that since there is no evidence to prove it true then it is false A)
C cannot be the correct answer because the stimulus never gives us an alternative explanation. For clarification, let's breakdown the stimulus.
First, it provides us with a study that finds that "P" sometimes occurs in mammals.
Then it states that this study is flawed and that there is no additional evidence of "P" occurring in mammals.
It concludes with stating that something must prevent "P" from occurring in mammals.
The stimulus assumes that because there is no evidence of "P" occurring in mammals it must not occur. This is choice A. I think, you guys are getting tripped up by C because in the conclusion, the stimulus offers a new hypothesis for why "P" doesn't occur. But notice that this new hypothesis is simply tacked on; it's not actually part of the argument that results in the conclusion that "P" never occurs in mammals.
I'm really confused with the "takes for granted" in answer choice A. Can I reword that in my head as "assumes?" It's really throwing me off when I try to think about what comes after it.
I understand the main flaw is "lack of evidence to prove position as true taken to prove position as false."
So is answer choice (A) saying that the author's flaw is that he/she ASSUMES that lack of evidence (to prove mammals use parthenogenesis) is taken to prove position as false (mammals cannot do pathenogenesis)?
Yes you can! Many Flaw in the Reasoning answer choices will describe some kind of flawed assumption that the author is making. That can be stated explicitly as "assumes", "presumes", "presupposes", or even "takes for granted."
Your description of answer choice A is exactly right. The author is essentially arguing that because no studies have shown mammalian parthenogenesis does exist, then it must not exist.
Hope that helps!
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