Q23 - Linda says that, as a scientist,

[yahoo]

Can someone help me break this down?

This is how I interpreted it:
Scientist----> Do not appreciate poetry

Scientists---M--> Logical

Appreciate Poetry <---S---> Illogical

I don't understand how this translates to answer B.

Thanks

[giladedelman]

Thanks for your question.

This problem requires us to find the answer that matches the flawed reasoning in the argument. So, diagramming is helpful, but it's also our job to articulate what the flaw is. In this case, the flaw is the attribution of a particular quality to some members of a group about which we know nothing, simply on the basis that most members of a different, non-overlapping group have the opposite quality.

(B) shares this flaw. No father wants his kids to eat candy at bedtime. Since most fathers are adults, some of the people who do want their kids to eat candy at bedtime must be children (i.e., not adults). But we don't know anything about the people who want their kids to eat candy at bedtime, just as we don't know anything about people who appreciate poetry!

Did you try diagramming (B)? I'll use your methods for the sake of consistency:

Father ---> does not want kids eating candy at bedtime.

Fathers ---M---> adult

Want kids eating candy at bedtime <----S----> children

It's identical! We have a match.

(A) is logically valid. If no marsupials lay eggs and most are native to Australia, there must be some non-egg-laying animals native to Australia.

(C) would be perfectly valid if it said that most California wine is inferior to at least the best French wine aged in oak. The flaw is just the omission of the word "most" there.

(D) is valid. If all color film is less sharp than black-and-white and most instant film is color, there's at least some instant film that's less sharp than black-and-white.

(E) is very tempting. It would match the flaw if it said that at least some people who like to pay taxes are dishonest people, because the original argument assigns to the group about which we know nothing the opposite trait from the group about which we do know something.

Does that clear this one up for you?

[cyruswhittaker]

When first doing this problem, I tried forming the conditional statements to isolate the flaw, but I feel like the conditional statements really work better to help mirror the flaw.

Sometimes with flaws involving group errors, Venn diagrams really seem to help. Do you have any opinion when Venn diagrams should be used with these types of questions?

[giladedelman]

Hmm, I'm intrigued but also a little confused by your post. What do mean when you contrast mirroring the flaw and isolating the flaw?

Also, I don't have much experience using Venn diagrams, but I do see how sketching out the groups in these "group" questions could be helpful in determining what kind of overlap inferences we can make. What sorts of diagramming approaches do you use?

[JohnK613]

I'm wondering if I attacked this problem wrong. I got the right answer, but when I did it I immediately eliminated answers A, C, and D because of the difference in wording from the stimulus. How it's "as a scientist, she knows that no scientist" compared to "as an expert in biology, he knows that no marsupial." The stimulus speaks for a group itself, not about things that the group has expertise on. Was I correct in immediately eliminating those answers, or did I just get a bit lucky?