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 Administrator
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#23136
Complete Question Explanation

Flaw in the reasoning—SN. The correct answer choice is (B)

The stimulus lays down the following facts in a necessary-sufficient format: specialized farms existed only when there are large commercial markets and urban populations:
  • Specialized farms ..... :arrow: ..... Urban population
The region of Kadshim did not have these specialized farms, but rather mixed farms. Thus, the stimulus concludes, the ruins of Kadshim were not of a densely populated city:
  • Specialized farms ..... :arrow: ..... Urban population (this is a mistaken negation)
Often when we notice conditional errors in reasoning like this one, it is worthwhile when answering flaw questions to quickly scan the answers for words like "sufficient," "necessary," and their synonyms.

Answer choice (A) The stimulus does not generalize from an observed sample to a larger population in this manner. The problem involves erroneous sufficient-necessary reasoning, not improper generalization.

Answer choice (B): This is the correct answer choice. Since this is the only answer choice that uses a conditional term—"necessary"—we should quickly recognize that it deserves close consideration. When we break down this answer choice, we can see that it is accurate: The argument erroneously takes the nonexistence of something (the specialized farms), and concluding that a necessary precondition for such farms (urban population) did not exist. Indeed, errors involving sufficient-necessary reasoning can be identified in a multitude of ways, some general and some more specific.

Answer choice (C) The argument does not equivocate with respect to a specific term. There is no indication that the meaning of a word or phrase is being interpreted in different ways to support the argument.

Answer choice (D) The argument does not erroneously make a causal claim based on evidence of correlation. The argument never states that urban populations cause specialized farms or vice versa, only that the former is necessary to the existence of the latter.

Answer choice (E) The argument does not make a circular argument. Its conclusion is not simply a restatement of its premises because the conclusion is actually a misstatement of its first premise.
 mjb514
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#41099
Can you please explain how the specialized farms are deemed as nonexistent.
 Francis O'Rourke
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#41114
Hi mjb,

In the stimulus, the speaker states that this land "could never have supported any farms except mixed farms." This means that the land could not have supported specialized farms. Let me know if this helps! :-D
 Blueballoon5%
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#45494
Hello! I got the right answer, but I am having trouble with understanding one of the premises in the stimulus. The premise reads, "... and such markets presuppose urban populations."

The word "presuppose" means to assume, right? It doesn't seem to be a sufficient/necessary indicator. However, the question relies on our understanding that this sentence translates to the follow conditional statement: "Large Commercial Markets :arrow: Urban populations." Is the word "presuppose" in the LSAT a conditional indicator? If so, what does "presuppose" modify--the "markets" or the "urban populations"?

Thanks!
 Adam Tyson
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#49742
"Presuppose" is indeed a conditional indicator, blueballoon! It does mean assume, and as we know from our study of assumption questions, assumptions are thought to be necessary by the author. So, "presupposes" means "requires" or "makes necessary"! If one thing presupposes another, then the first thing is sufficient for the second, and if something is presupposed by another thing, then the first thing is necessary for the second.

Add that to your list of conditional indicators! You will see it again.
 bbjigglercakes
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#92955
Adam Tyson wrote: Fri Aug 17, 2018 3:21 pm "Presuppose" is indeed a conditional indicator, blueballoon! It does mean assume, and as we know from our study of assumption questions, assumptions are thought to be necessary by the author. So, "presupposes" means "requires" or "makes necessary"! If one thing presupposes another, then the first thing is sufficient for the second, and if something is presupposed by another thing, then the first thing is necessary for the second.

Add that to your list of conditional indicators! You will see it again.

when presuppose is right in front of the term does the term behind that indicator become the NA. I got this question right by seeing conditional reasoning in the stimulus and scanning for SA and NA indicators in the answer choice but i found my diagram a bit dodgy because i wasnt sure what presuppose was refferring to.

My diagram is this:
Specialized farm --> large commercial market --> urban populations.


i.e. such markets presuppose urban populations.

my confusion:
is the market required for the urban pop. and thus: urban pop --> market
or is the urban pop required for the market: market --> urban pop

such markets require urban populations --> is this basically what is being said? the presuppose is throwing me off
 Adam Tyson
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#93001
If one thing presupposes another thing, the thing that is presupposed is a necessary condition, bbjigglercakes, and the thing that presupposes it is sufficient. Here is an example:

My plan to have dinner at 7pm presupposes that I will not get stuck in traffic on the way home.

Dinner at 7 :arrow: Stuck in Traffic

Think about "presupposes" as meaning the same thing as "requires" and you won't have any trouble with it at all!

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