#8 - Of the many works in a collection from Japan’s

[Administrator]

Please post your questions below!

[gcs4v333]

I thought this was a really difficult #8. I eliminated (B) (C) and (D), and then guessed (A) just as time ran out. Let me see if I can tease out the reasoning.

MSL = Pieces most sensitive to light
MVP = Most valuable pieces
2wks = On display for two weeks only
SA = Sakai Hoitsu's "Spring and Autumn"

MSL & MVP 2wks

2wksSA MVP

Which is a mistaken reversal, and also MVP refers to a collection of pieces that are valuable. Just because Spring and Autumn is only displayed for two weeks doesn't mean it's the MOST valuable.

And then answer choice (E):

HM = Historical monuments
H = Hospitals
PD = Purple dots
WS = Wilson Street

HM & H PD

PDWS HWS

Which is also a mistaken reversal. I guess what threw me was A) The language in the answer choices, which made the relationships difficult to keep track of and B) Seeing the conditional relationships without the use of conditional language. In general, if something "is" or things "are" something then the thing is in the sufficient position, and the group they belong to in the necessary, right? For example, "Dogs are mammals" the thing, Dogs are sufficient and the group they belong to "mammals" are the necessary, for a diagram of Dogs Mammals, correct?

[Adam Tyson]

I like your analysis at the end, gcs4v333, of the "dogs are mammals" approach to conditional statements without classic indicators. I often refer to that as the "category/characteristic" approach, where we are given a category of things that all have a certain characteristic, and the category is sufficient to make the characteristic necessary. Great minds think alike!

As to your diagrams, I would suggest that those "and" signs be switched to "or", because it is the case that if a piece is among the most valuable OR if it is sensitive to light, then it is on display for only two weeks.

Also, note that the author's mistake was not in saying that SA was the most valuable (because that's not what he said), but that it must be among the most valuable. It could also be that it is sensitive to light, or it could even be that neither sufficient condition is met, so it is a Mistaken Reversal with the added element of a second option. That is a multi-layered flaw, and you're right that it makes it more difficult than a typical question found this early in the section.

[g_lawyered]

Hi P.S.
I solved this question differently than the explanation above. I didn't translate into conditional statements. Instead I recognized that the original argument mistakenly left a requirement (necessary) condition out. Here's how I solved the argument. I understood the premise to mean that in order for the pieces to be on display for 2 weeks "it needed most sensitive to light as well as the most valuable pieces". I understood "as well" to mean it needed both sensitive to light AND most valuable pieces. Because the conclusion only mentions that the piece S.A. will be on display for 2 weeks because its "clearly among the most valuable piece". I understood the argument to be flawed because It needed to mention/ assume that S.A. is ALSO sensitive to light. I couldn't put a name of the actual flaw type but I need the action.

With my reasoning, by process of elimination I eliminated every answer choice except C. I noticed that C makes the same flaw in that it fails to mention " S Street needs to be marked with SOLID lines" because the conclusion states the mapmakers are wrong because S Street is marked with dotted lines". But what about the premise that states that "throughfares are marked with solid and dotted lines"? To me, that matched the flaw the original argument had.
What makes answer choice C wrong? And where did my reasoning going wrong in understanding the flaw in the original argument?

Thanks in advance

[katehos]

Hi GGIBA003,

In order to best understand this question, it's important to diagram the relationship between the sufficient and necessary conditions at work here. The sufficient condition is to be either among the most valuable pieces or be sensitive to light. We can discern that the use of "or" is the proper interpretation for the statement "those that are most sensitive to light, as well as the most valuable pieces, will..." because of how the clauses are separated by a comma. Then, we look to the necessary condition, which in this case is being on display for two weeks only.

This leads us to diagram the conditional as:
      STL or MV 2W

What follows is the flaw in reasoning by the author: a mistaken reversal. The author takes the necessary condition (being on display for two weeks) as an indication that the piece is among the most valuable.

Their reasoning looks like this:
      2W MV

You did a great job pointing out that being "most sensitive to light" was left out of the conclusion! This question is particularly difficult, though, since there are multiple layers of flaws here. We can say that argument is flawed not only because it failed to acknowledge that there are two options for sufficient conditions but also because the author reversed the sufficient and necessary conditions entirely.

With this in mind, we can see why answer choice (C) doesn't have the same flaw. Answer choice (C) says that "thoroughfares are marked by solid lines and that dotted lines designate one-way streets." We can interpret this to mean that thoroughfares are solid and one-ways are dotted, as opposed to thoroughfares are solid and dotted. This argument does not have the same flaw, then, and can be eliminated.

Turning to answer choice (E) we can see that the same flaws from the stimulus are present because either a hospital or a historical monument is designated by a purple dot, then the argument proceeds by asserting that because something is a purple dot, it must be a hospital. In the same manner as how the stimulus mistakenly took being on display for two weeks to mean art was among the most valuable, answer choice (E) mistakenly takes being a purple dot as being a hospital.

Hope that helps!
Kate