Thank you for your question. The key to a flawed parallel reasoning question such as this is to ensure that you have a strong grasp on the reasoning in the stimulus. So let's start there.
We can diagram each part of the stimulus:
Linda says that, as a scientist, she knows that no scientist appreciates poetry.
Let's focus on the second part of that sentence:
S ==> not AP [no scientist appreciates poetry]
Since most scientists are logical . . .
S-most-L [most scientists are logical . . . I'll come back to this in a moment]
At least some of the people who appreciate poetry are illogical
AP-some-not L [some of the people who appreciate poetry are NOT logical]
This is flawed. The transitive conclusion drawn does not actually follow.
Recall that "most" statements reverse as "some" statements.
Here is the transitive laid out:
Premise: L-some-S [some logical people are scientists; this is the correct "reversal" of the most statement "most scientists are logical"]
Premise: S ==> not AP [no scientist appreciates poetry]
Therefore: L-some-not AP [some logical people do not appreciate poetry]
Notice that the conclusion drawn, however, is different--"some of the people who DO appreciate poetry are NOT logical."
Look at it this way to see it most clearly:
P: S ==> not AP
P: S-most-L
C: AP-some-not L
Notice how the concept "not AP" has been erroneously converted to a different concept, "AP." And the concept "L" has also been erroneously converted to a different concept, "not L."
This is flawed reasoning.
Answer choice (B) is identical.
Premise: No father wants children to eat candy at bedtime. F ==> not WCECB
Premise: Most fathers are adults. F-most-A
[False] Conclusion: WCECB-some-not A ["are children" is diagrammed here as "not adults"]
But the correct transitive from the premises in answer choice (B) is as follows:
A-some-F ==> not WCECB
Therefore: A (some) (not) WCECB [some adults do not want children to eat candy at bedtime]
Again, look at answer choice (B) from above:
P: F ==> not WCECB
P: F-most-A
C: WCECB-some-not A
Just as in the stimulus, both key concepts have been erroneously converted. The concept "not WCECB" has been erroneously converted to a different concept, "WCECB." And the concept "A" has also been erroneously converted to a different concept, "not A."
That's parallel. That's the answer.
Answer choice (A) is not flawed. That is a correctly drawn transitive argument.
Answer choices (C) & (D) are similar to each other, but not to the stimulus.
Answer choice (E) can be diagrammed:
Premise: CE ==> not LPT [no corporate executive likes to pay taxes]
Premise: CE-most-HP [most corporate executives are honest people]
[False] Conclusion: LPT-some-HP [some people who DO like to pay taxes are honest people]
The correct conclusion from the transitive would be:
HP-some-CE ==> not LPT
Therefore: HP-some-not LPT [some honest people do NOT like to pay taxes]
The difference between this answer choice and the stimulus and correct answer (B) is that the second part of the conclusion is not incorrectly canceled out in answer choice (E):
P: CE ==> not LPT
P: CE-most-HP
C: LPT-some-HP
Although the concept "not LPT" has been erroneously converted to a different concept, "LPT," the second concept, "HP," remains "HP" in the conclusion. It is not a parallel flaw to the stimulus.
Hope that helps! Please let us know if you have any additional questions.
charlierusso04August 9, 2019
I am a bit confused about distinguishing a sufficient sentence and a quantifier. I know the words that identify sufficient statements, for example the word "if" is followed by "some" do we digram it as sufficient and necessary or as a quantifier? "If some of the people play basketball, they are tall." i just need some clarity on this, thanks.
RaviAugust 9, 2019
@charlierusso4,
Great question.
For the example you gave, you would digram that as
some of the people play basketball - >they are tall
"If" would signal to diagram this as a sufficient and necessary relationship. You wouldn't diagram this as a quantifier because it just wouldn't make sense. Think about what the sentence is saying. The if is introducing a clause that's the sufficient condition, and we know that just if some (at least one) of the people play basketball, then the necessary condition (they are tall) has to follow.
Does that make sense? Let us know if you have any other questions!
