Q21 - Sociologist: Traditional norms in our

[ManhattanPrepLSAT1]

Evidence:
If a society ignores unpleasant realities or tells small lies, then that society prevents sincerity.

IUR or TL → ~Sincerity

If a society does not trust one another then that society cannot succeed.

~Trust → ~Succeed (Contrapositive Succeed → Trust)

Conclusion:

If a society is to succeed then that society must not ignore unpleasant realities nor tell small lies.

Succeed → ~IUR + ~TL

So the argument could be organized as follows


Succeed → Trust
{What’s the gap?}
Sincerity → ~IUR + ~TL
_____________________

Succeed → ~IUR + ~TL

The gap is...

Trust → Sincerity restated in answer choice (A)!

(A) is the correct answer.
(B) is a relative claim. This argument is not about the more of this then the more of that.
(C) undermines the argument. If a community could succeed even if its members subscribe to traditional norms, then the conclusion of the argument would no longer hold.
(D) is already stated in the first sentence of the stimulus _ so it won’t fill the gap in the argument.
(E) is wrong when it brings up causation. This argument is strictly based on correlations, not cause and effect.

[sunhwa2881]

When I was doing this problem, I wrote the first evidence as

IUR and RL → ~Sincerity

because the first sentence reads "Traditional norms in our society prevent sincerity by requiring one to ignore unpleasant realities and tell small lies." Your explanation certainly makes sense. But can you please explain why you used OR instead of AND so I know what I did wrong?

[ManhattanPrepLSAT1]

Looking back I see the word "and." Since ignoring unpleasant realities and telling small lies prevent sincerity, either one of them by themselves is sufficient to lead to a lack of sincerity.

Sometimes the word "and" can be used and an "or" is implied. It's not frequent, but sometimes it just makes the most logical sense.

Take this example.

If I study this afternoon and if play basketball this afternoon, I will not have coffee with my friend.

translates

S or PB --> ~C

They're a bit loose with the notation in question 21. But since the gap is somewhere else in the argument (between sincerity and trust) I think it's best to simply grant them them the association between facing unpleasant realities and telling small lies.

[skapur777]

I thought the first part was:

~sincerity>IR and/or SL

I thought the word "require" shows that they are necessary and not sufficient?

[daniel.g.winter]

I agree with skapur. I got this right but on a somewhat lucky guess (had eliminated 3/5 answers). I would diagram the first sentence as:

~Sincerity --> IUR and TSL (~IUR or ~TSL --> Sincerity)

I see how you did the rest clearly, but I am at a loss as to how you came up with your diagram for this part.

[farhadshekib]

I agree with skapur. I got this right but on a somewhat lucky guess (had eliminated 3/5 answers). I would diagram the first sentence as:

~Sincerity --> IUR and TSL (~IUR or ~TSL --> Sincerity)

I see how you did the rest clearly, but I am at a loss as to how you came up with your diagram for this part.

I have the same question...

I thought "required" denotes necessity, so if one wants to prevent sincerity, one must ignore unpleasant realities and tell small lies.

Can you please elaborate, Matt?

[ymcho2013]

"traditional norms in our society prevent sincerity by requiring one to IUR and TSL"

so TN requires IUR and TSL, which thereby prevents sincerity.

therefore:

TN --> IUR and TSL --> ~S

therefore:

IUR and TSL --> ~S

[curvedhyperbole]

Agreed. Unsure how "by requiring" functions. Thanks!

[joseph.m.kirby]

So this problem is a sufficient assumption and we will need to find and fill the gap so that the conclusion follows.

"Sincerity is prevented by requiring one to ignore unpleasant realities and tell small lies." In other words, the ignoring of unpleasant realities (IUR) and the telling of small lies (TSL), in this particular instance, cause the preventing of sincerity (PoS).

P: TSL & IUR --> PoS

A community whose members do not trust (~T) each other cannot succeed (~S).

P: ~T --> ~S

So, to succeed, the community must be willing to face unpleasant realities (~IUR) and speak about them honestly (~TSL)

C: S --> ~IUR & ~TSL

Let's bring everything together:

P: TSL & IUR --> PoS
P: ~T --> ~S
-----------------
C: S --> ~IUR & ~TSL

Next, let's locate the gap. It seems the gap lies between premises 1 and 2. Let's take the contrapositive of the conclusion to make it easier to visualize.


P: TSL & IUR --> PoS
P: ~T --> ~S
-----------------
C: IUR | TSL ---> ~S

We see the gap relates to PoS --> ~T or T --> ~PoS which is (A)

[austindyoung]

Awesome posts, and Matt is right on. I think there is a way to make this easier as well, just to add my two cents.

It still invovles formal logic, but, there is a cool way to condense this and make it a lot easier so that the connection really pops out.

We have this:



TN---> (I+ L) --->~SI (First Sentence)


SU--->TR (Contrapositive of Second Sentence)
------------

SU--->(~I+~L) (Last Sentence/Conclusion)

(Note: Because of formatting I put these in parenthesis, but usually I would draw the arrow right towards the "+/and")

Before we move on- let's condense. See what the conclusion implies? It invokes the contrapositive of the first sentence. So, for the conclusion, though seemingly superfluous, we could add the (~TN) there.

So, we can line up the necessary conditions, and take out the repeat terms (since ther are sufficent for something elese within the given conditional chain; i.e., intstead of A--->B--->C we'll put A--->C).

We end up with this much easier diagram:

SI--->~TN (Contrapositive of 1st sentence, w/out repeat terms)
SU--->TR (Contrapositive of 2nd sentence)
-----------
SU--->~TN (Conclusion, w/out repeat terms)

Now, we can see that the bolded is where the link needs to be made.

Assumption: TR--->SI or ~SI--->~TR. (A) is the first of these two.

Simple as that! We didn't need the repeat terms, because they were just getting in the way and didn't deal with the assumption at hand. We knew they were there, but there weren't on the ends of the chain- they didn't need to be connected.

Key: (I=Ignore unpleasant realities; L= Tell small lies; TN= Traditional Norms; TR= Trust; SI= Sincerity; SU= Succeed)

[PhoebeL747]

I think if we translate the first sentence in a way that will line up its necessary condition
with the necessary condition of the conclusion, the diagram will be less complicated and the gap will be more obvious.

The first sentence essentially says: Sincerity requires facing unpleasant reality and not lie
( Si--> FUR + -L)

Second premise: Success requires trust (Su-->T)

Conclusion: Success requires facing unpleasant reality and not lie (Su-->FUR + -L)

Gap: Trust requires sincerity (T-->Si)

There are instances that a sentence can lead to different interpretations notation-wise. To make it work, I would try to translate it in a way that will line up its necessary condition with that of the conclusion. Or not to notate at all, just reason through it.

[MarieM777]

I think my confusion stems from polar and logical opposites. I wanted to go the route Phoebe did, but then I thought FUR and SH = IUR and TSL (respectively) were polar opposites...not logical. So they were separate factors in my diagram. Same with ~PS = Si. Just because something does not prevent sincerity does not mean it is sincere...or so I thought.

I was down to choices (D)/(A) and ultimately chose D because it involved what I thought were new factors (FUR and SH).

FUR = Face Unpleasant Realities
IUR = Ignore...
SH = Speak Honestly
TSL = Tell Small Lies
PS = Prevent Sincerity
Si = Sincerity