Excavations of the Roman city of Sepphoris...

[MinwooK499]

Is answer choice A wrong, because if the statement is negated and the mosaics were made with rocks exclusively from Sepphoris, the stones could have been imported to other Roman cities where the traveling artisans are from? therefore answer choice A is not a required assumption?

[RonPurewal]

choice A is not required because it is completely unrelated to the argument.

the argument is basically this:
'there are mosaics in sepphoris that show animals from outside sepphoris.
thus, the artists who made them must have come from outside sepphoris.'

with the argument in these smiplified terms ('explain to a 9-year-old'), you should be able to see why the provenance of the stones themselves doesn't matter.

[RonPurewal]

choice A **might** have something to do with where the art was created (and even that connection would still be pretty tenuous)...
...but we're not arguing about where the art was created. we're arguing about the origins of the people who created it.

[RichaChampion]

remember that you're looking for REQUIRED ASSUMPTIONS.

here's a very useful criterion to use in these problems:
try REVERSING putative assumptions and see the effect on the argument.
if you REVERSE A REQUIRED ASSUMPTION, the ARGUMENT SHOULD BECOME INVALID.

let's try this with your top 3 choices:

(b)
reverse this assumption: let's say all the species are indigenous to some common region.
this doesn't destroy the argument; it's perfectly consistent with the idea of traveling artisans (who presumably would have come from that common region).
wrong answer.

(d)
reverse this assumption: let's say that there are some animal figures that are not readily identifiable.
this has no effect whatsoever on the argument, which is concerned only with some of the animal figures (i.e., the ones that weren't native to the local area).
wrong answer.

(e)
reverse this assumption: let's say there was a common repertory of mosaic designs.
in this case, that repertory - since it was a common repertory - would have included animal figures from all over the place. (at the very least, it would be quite unreasonable to expect a common repertory to have been restricted to animal figures from the sepphoris area in particular.)
this destroys the argument, because, were there such a repertory, then artists local to sepphoris would have followed it as well, creating the exotic designs despite their status as natives in the area.
correct answer.

Ron I have one question in general for Option C -
C. No motifs appear in the Sepphoris mosaics that do not also appear in the mosaics of some other Roman city.

Their is one "No" and another "do not" so my question is once we negate then which portion should we negate "no" or "do not" or both?

C. No motifs appear in the Sepphoris mosaics that do not also appear in the mosaics of some other Roman city.

[RonPurewal]

this is the kind of thing you should just do with your own common sense, plus some analogies.

e.g.
I don't have any friends who don't watch sports.

if this is false, then, we know that __________

... then just apply the same reasoning here.

[sandeepr433]

Hi Ron,

On negating option C,
"Motifs appear in the Sepphoris mosaics that do not also appear in the mosaics of some other Roman city "

But,
The question stem says "Since identical motifs appear in mosaics found in other Roman cities"
Are these both contradicting each other?
Are we assuming something which we should not?

I negated C and chose C as the right answer

Thanks!

[RonPurewal]

nah. just replace the word "motifs" with "specific pictures/drawings".

the passage tells us about some of the pictures in these mosaics (specifically, the ones depicting certain animal species). however, there's no reason to believe that these are ALL of the pictures.

choice C is much, much more extreme -- it's equivalent to saying "ALL of the pictures from sepphoris were also found in other cities."

[RonPurewal]

also, keep in mind that "assumptions" will NEVER just restate information that's already there, and passages will NEVER contradict themselves.

if you think that either of these things is happening, then you are DEFINITELY misinterpreting something, and you need to reconsider how you're reading the words of whatever choice you happen to be reading.

[AndreiK316]

I tend to get easily confused with double negative sentences, because it is hard to translate them into the understandable language.

Let me try to convert them to the "normal" language:

(1) No motifs appear in the Sepphoris mosaics that do not also appear in the mosaics of some other Roman city.
= Some motifs that appear in the Sepphoris mosaics that also appear in the mosaics of some other Roman city.
Basically double negative = positive, right? With the only exception of the word "Some"

(2) No motifs appear in the Sepphoris mosaics that also appear in the mosaics of some other Roman city.
= Motifs in Sepphoris mosaics do not appear in mosaic of other Roman cities.

(3) Motifs that appear in the Sepphoris mosaic do not also appear in the mosaics of some other Roman city.
= Motifs in Sepphoris mosaics do not appear in mosaic of other Roman cities. (Same meaning as in sentence (2)?)

My example:
(4) No people who eat chocolate, do not eat cookies.
= Some people who eat chocolate eat cookies?

Please, let me know if I translated all 4 sentences correctly?

[RonPurewal]

the way to do this is to consider SIMPLER sentences FIRST.

like this:
There's nobody here who doesn't like green olives.

...this means the same as
Everybody here likes green olives.

note—you are NOT using any sort of "rules" or "formal logic" to make this transformation; it's basically just raw common sense.

by the same token, #1 is going to turn into... All of the Sepphoris motifs also show up in some other Roman city's mosaics.

__

try the others again on your own, using simpler analogies first. see how that goes.

[AndreiK316]

Thank you, RonPurewal

Simpler Sentences First:

(1) Nobody who likes chocolate, likes cookies =
Those who likes chocolate, don't like cookies.

(2) Nobody who likes chocolate, don't like cookies. =
Those who like chocolate, like cookies.

These sentences convert with the same outcome:
(3) No motifs appear in the Sepphoris mosaics that also appear in the mosaics of some other Roman city.
= All Motifs in Sepphoris mosaics do not appear in mosaic of other Roman cities.

(4) Motifs that appear in the Sepphoris mosaic do not also appear in the mosaics of some other Roman city.
= All Motifs in Sepphoris mosaics do not appear in mosaic of other Roman cities. (Same meaning as in sentence (3)?)

Did I get it correctly?

[RonPurewal]

#1 and #2 are fine.

#3 and #4 are problematic, because you're using a sentence structure that can't ever be used in well-written english. you CANNOT combine "both", "all", or "X and Y" with a negative.

as an illustration of why not—consider the following sentence:
All the girls here do not have short hair.

it's impossible to tell whether this means...
..."all the girls here have long hair"
OR
..."it's false that all the girls here have short hair" (which only means that AT LEAST ONE girl has long hair).

the same ambiguity will ALWAYS exist in any attempt to write "all"/"both"/"and" + negative. so, you can't use that combination.
if you are thinking about writing "All X's do not Y", then write one of the following instead:
...No X's do Y,
...At least one X does not Y.

so, try #3 and #4 over again.

also, I'm not sure where you are even getting the sentences for #3 and #4—note that neither of those is the same as the original answer choice (you're missing a "not").

[AndreiK316]

Hi Ron,

Thanks for reply

also, I'm not sure where you are even getting the sentences for #3 and #4—note that neither of those is the same as the original answer choice (you're missing a "not").

I removed "not" just for the sake of practice.

(1) Would you agree that both sentences have the same meaning:
*No motifs appear in the Sepphoris mosaics that also appear in the mosaics of some other Roman city.
*Motifs that appear in the Sepphoris mosaic do not also appear in the mosaics of some other Roman city.

Both sentences bear the same meaning: motifs in Sepphoris and Roman city are different

(2)

All the girls here do not have short hair.

What is wrong with it?
Ex: all the kids don't like to study.

Appreciate your explanation

[RonPurewal]

ok, so, you MIGHT perfectly understand what's going on here... the problem might just be the words.

your #1 examples are too clunky -- they just have too many words to discuss easily, and i think that's the problem -- so, here are some examples with fewer words.

Say X and Y are companies.

No employee of X has worked for Y.
—> this is the same as saying... All employees of X have never worked for Y. (...this is a weird/awkward way to say this, but it's the same message)

the problem with your second version is that it's a weaker statement. it's like writing
Employees of X have never worked for Y.
here, ***YOU MIGHT HAVE MEANT*** to talk about ALL employees of X, but ... that isn't what these words mean. if you just write "employees of X", that doesn't necessarily mean all of them.

hopefully you see the problem.

your first statement #1 could be translated into something like... "ALL motifs in the Sepphoris mosaics ARE UNIQUE TO the Sepphoris mosaics (i.e., DO NOT appear in any OTHER city's mosaics)".

[RonPurewal]

(2)All the girls here do not have short hair.
all the kids don't like to study.

the problem with these sentences ^^ is that we don't know what they mean.

imagine that "not" is an algebraic minus sign.
then the problem is that ... we don't know where the minus sign goes.

"ALL the girls do NOT have short hair" COULD mean...
"–(All the girls have short hair)" —> "it's false that all the girls have short hair" —> "AT LEAST ONE girl has LONG hair"
*OR*
"All the girls have –(short hair)" —> "ALL the girls have LONG hair"

same thing with "all the kids don't like to study"
this could mean...
–(all kids like to study) —> "at least one kid doesn't like to study"
OR
all kids –(like to study) —> "all the kids hate studying" / "NO kid likes to study"

--

this is honestly my best attempt to explain this—there is literally no possible way i could explain this beyond what i've already written here.
...so, hopefully this makes sense now (:

if this still doesn't make sense, then just memorize: you can't combine "all"/"both"/"and" + negative.