Quantifiers Questions - - Question 5

Linda says that, as a scientist, she knows that no scientist appreciates poetry. And, since most scientists are logic...

naryanshukle July 16, 2020

Children vs not adults

Hi, I dismissed B as a correct answer due to the wording of children v "not adults". My understanding was that answer B conflated someone as being a child, instead of not an adult, where the two terms are never compared in the text. I deemed it out of scope as a child's desires are never discussed. The video claims that "we know if you're a child, you're not an adult."Right from the outset it seemed to me that drawing on external knowledge of children v adults was improper. But even if that were appropriate, the video then argues "not-adult" MUST be a child. Just because someone is not an adult, there is nothing requiring them to be children. Child ----> Not Adult This is the assumption the video makes, which you teach as wrong since it is a fact that never appears in the stimulus, nor is it a deduction since children are never mentioned. But even if this were in the stimulus, the video then confuses the contrapositive by saying: Not Adult -----> Child (incorrect, since is would be Adult ---> Not Child) Am I misunderstanding the video, or is there another reason B would be incorrect? PS: My issue was not that I thought other answers were right, I simply eliminated all answers as wrong, including B, and was left with nothing.

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naryanshukle July 16, 2020

**Is there another reason B would be CORRECT

Ravi July 16, 2020

@naryanshukle,

Let's take a look at (B).

Diagramming the stimulus, we have

1) S-->/AP

2) S--most-->L

3) AP<--some-->/L

Looking at these diagrams, we see that the flaw is that the first two
statements do not imply the third statement. Combining the first two
statements, we have /AP<--some-->L.

However, the argument gives us the inverse, negating L instead of AP.

We want an answer choice that has this same type of structure and
identical error in its conclusion.

Looking at (B), we have

F-->/WCEC

F--most-->Adults

WCEC<--some-->/Adults

This matches the structure of the stimulus, so it's the correct answer choice.

Does this make sense? Let us know if you have any questions!

naryanshukle July 20, 2020

Thanks for the breakdown! However my issue was equating *children* with *not Adults* (the third line in your diagram) . I failed to diagram the third line of B as you did, because I never deduced *children = not adults*; this made me eliminate B. Is there a reason we can safely make this connection, even though *children = not Adults* is an assumption not directly stated?