Some visitors to the park engage in practices that seriously harm the animals. Surely, no one who knew that these pra...

Victoria on June 15, 2020

Hi @Harper,

Happy to help!

This is a Parallel Reasoning question. We are looking for the answer choice which employs the same pattern of reasoning as that used in the stimulus.

The first step is to map out the reasoning used in the stimulus so that we can compare it to the reasoning used in each answer choice.

"Some visitors to the park engage in practices that seriously harm the animals."

VP - some - SHA

"No one who knew that these practices seriously harm the animals would engage in them." In other words, "if they knew the practices would harm the animals, then they would not partake in them."

K --> Not SHA
SHA --> Not K

Therefore, "it must be concluded that some of the visitors do not know that these practices seriously harm the animals."

Remember that we can make valid deductions using quantifiers as long as: (1) there is a S&N statement; and (2) they have the S condition in common.

VP - some - SHA
SHA --> Not K

Therefore:

VP - some - Not K

So, what was the pattern of reasoning used here?

We combined a quantifier statement with the contrapositive of a S&N statement to draw our conclusion. We are looking for the answer choice that does the same thing.

Answer Choice (C):

"Some people polled live outside city limits"

PP - some - OCL

"No one who can vote in city elections lives outside the city." In other words, "if you can vote in city elections, you cannot live outside the city."

VCE --> Not OCL
OCL --> Not VCE

"Therefore, some of the people polled cannot vote in the upcoming city election."

PP - some - Not VCE

This answer choice uses exactly the same pattern of reasoning as the passage: it combines a quantifier statement with the contrapositive of a S&N statement to draw its conclusion. Therefore, answer choice (C) is correct.

Answer choice (A) is incorrect because there is a gap in its reasoning. We know that some of the people who worked on the project will be fired and that everyone in this department played an important role in the project. However, it is possible to play an important part in a project without actually working on it; therefore, we cannot conclude that some people in this department will be fired.

Answer choice (B) is incorrect because of the difference in S&N statements. The stimulus says that "no one who knew that these practices seriously harm the animals would engage in them."
This answer choice says that "the mayor denounced everyone who signed the petition." In other words, "if you signed the petition, you were denounced by the mayor."

SP --> DM
Not DM --> Not SP

Note the difference between this S&N statement and the one we diagrammed from the stimulus:

K --> Not SHA
SHA --> Not K

Answer choice (D) is incorrect because it does not include a quantifier statement. Both premises are S&N statements.

Answer choice (E) is incorrect for the same reasons as answer choice (B). "All members of the city council are opposed to the proposed ordinance.

MCC --> OPO
Not OPO --> Not MCC

Hope this helps! Please let us know if you have any further questions.