Q14 - Novelists cannot become great as

[peg_city]

Can one of the geeks tell me if I diagrammed this right

NG -> ~RIA
RIA -> ~IGOE/~IEDL

D) NG -> IGOE

Is this right? If D said IGOE -> NG it would be wrong, correct? Is NG the sufficient condition here because it was in the conclusion?

Thanks

[theaether]

hey, let me take a shot. your diagramming looks perfectly sound. i do it with some word abbreviations because sometimes i get confused translating the acronyms to the stimulus's conditions.

conclusion:
academia --> ~great

premises:
1) academia --> ~immersion
2) grasp of emotions --> immersion
3) Contrapositive of 2): ~immersion --> ~grasp of emotions
4) Linking 1) and 3): academia --> ~grasp of emotions

So academia leads to no immersion, and therefore no grasp of emotions. But why would that mean academia leads to not being a great novelist?

possible required assumptions: Something that tells us great novelists require something that academia precludes.
1) great --> immersion
2) great --> grasp of emotions

Choice (D): ~grasp of emotions --> ~great, which is the contrapositive of our second expected required assumption!

As for your question, IGOE-->NG (grasp of emotions --> great) is a reversal and wouldn't help bring the premises and the conclusion together. Such an answer choice would be a premise booster, just telling us that academia --> ~great --> ~grasp of emotions.

[ManhattanPrepLSAT1]

Let me add one more attempt at this. Though I do see your versions above.

The argument is structured in the following way.

IGEL ---> ~RA
-----------------
NG ---> ~RA

(Notation Key: IGEL = intuitive grasp of the emotions of everyday life, RA = remain in academia, NG = novelist to become great)

Abstractly it looks like:

B ---> C
------------
A ---> C

The assumption being A --> B

And in the case of this question NG ---> IGEL, perfectly stated in answer choice (D). Notice that if a condition in the conclusion appears as a sufficient condition, then in the evidence it too must appear as a sufficient condition. If a term appears as a necessary condition in the conclusion, then again, it must appear as a necessary condition in the evidence.

Hope that helps!

[romanmuffin]

mshermm,

Going off of your example,

Could the assumption be B --> A?

Is this what you were trying to address in your statement about sufficient in conclusion meaning sufficient in evidence? I don't really understand what you meant by that

[timmydoeslsat]

mshermm,

Going off of your example,

Could the assumption be B --> A?

Is this what you were trying to address in your statement about sufficient in conclusion meaning sufficient in evidence? I don't really understand what you meant by that

The assumption you provided of B ---> A would not make it a valid argument.

Here is why.

If this is the argument we are given:

B ---> C
____________
A ---> C

We clearly see that there is an assumption involving A, as it is mentioned in the conclusion and not the premises.

To insert [B ---> A] into the argument would not allow for our conclusion to follow logically.



B ---> C
B ---> A
____________
A ---> C


All we have done now with our evidence is to show that B requires A and C. We have absolutely no evidence to infer that A requires C or that C requires A. We do not know if either variable requires anything!

As Matt said, having A in the sufficient condition of the conclusion makes us look for A as a sufficient condition in the evidence presented.

So, in this case, we would have [A ---> B]

B ---> C
A ---> B
____________
A ---> C

Now we can infer our conclusion logically.

[ManhattanPrepLSAT1]

Nice explanation Timmy!

[kelseyjschutte]

Can someone explain why E cannot be correct? Preferably not in notation.

[griffin.811]

Can someone explain why E cannot be correct? Preferably not in notation.

Hi Kelsey,

I spent more time on this question than I would have liked as well. Figured I'd I check out the discussion, but I'm not a fan of diagramming for LR.

Anyway, to answer your question, E is incorrect because "having knowledge of the emotions of everyday life" is not the same as having an "intuitive grasp" on the emotions of everyday life.

So maybe our teachers, have acquired knowledge via observing and analyzing, but they may still lack this intuitive grasp.

[damnsky]

Let me add one more attempt at this. Though I do see your versions above.

The argument is structured in the following way.

IGEL ---> ~RA
-----------------
NG ---> ~RA

(Notation Key: IGEL = intuitive grasp of the emotions of everyday life, RA = remain in academia, NG = novelist to become great)

Abstractly it looks like:

B ---> C
------------
A ---> C

The assumption being A --> B

And in the case of this question NG ---> IGEL, perfectly stated in answer choice (D). Notice that if a condition in the conclusion appears as a sufficient condition, then in the evidence it too must appear as a sufficient condition. If a term appears as a necessary condition in the conclusion, then again, it must appear as a necessary condition in the evidence.

Hope that helps!

Thanks mattsherman. I have a question that has bothered me for a long time.

I understand the assumption should be A --> B, but isn't it a sufficient assumption rather than a necessary assumption as the problem asks for?

We know A --> B bridges the gap from B ---> C to A ---> C, so it should be a sufficient assumption of A ---> C. However, if I negate A --> B, which becomes
A --> ~B, it doesn't destroy the conclusion A ---> C. Then how can one say
A --> B is a necessary assumption of the conclusion A ---> C?

I am sure I am missing something here, but I just can quite figure it out...

[WaltGrace1983]

Thanks mattsherman. I have a question that has bothered me for a long time.

I understand the assumption should be A --> B, but isn't it a sufficient assumption rather than a necessary assumption as the problem asks for?

We know A --> B bridges the gap from B ---> C to A ---> C, so it should be a sufficient assumption of A ---> C. However, if I negate A --> B, which becomes
A --> ~B, it doesn't destroy the conclusion A ---> C. Then how can one say
A --> B is a necessary assumption of the conclusion A ---> C?

I am sure I am missing something here, but I just can quite figure it out...

A few things:

(1) This is definitely a necessary assumption question. You can get this from the question stem: Which one of the following is an ASSUMPTION on which the argument DEPENDS. "Depends" would imply that, without this assumption, the argument wouldn't work - the argument would not have the very thing it "depends on."

(2) Just because something is necessary doesn't preclude it from being sufficient. In this case, answer choice (D) is both necessary and sufficient. I'll show you why this works:

Intuitive grasp of everyday emotions can be obtained only by immersion in everyday life
+
This immersion is precluded by academia
-->
If in academia, novelists cannot become great

I didn't diagram this out when I was doing the problem, however the diagram would look something like this:


Academia --> ~Immersion --> ~Int. Grasp. Evrd. Emot

THEREFORE

Academia --> ~Novelist Great


The assumptions would be that immersion is necessary to greatness (aka, ~Immersion --> ~Novelist Great) or that having an intuitive grasp of everyday emotions is necessary for greatness (aka, ~Int. Grasp. Evry. Emot --> ~Novelist Great).

In this case, and like most LSAT questions, the assumption is about the two last links in the sequence, so to speak.

This assumption is sufficient because plugging this assumption in would make the argument 100% valid.

The assumption is also necessary because, without this assumption, one doesn't see how the premises have anything to do with the conclusion. In other words, the negated assumption would make the argument not make logical sense. If greatness did NOT require an intuitive grasp of everyday emotions, why did the author even bring it up? That is when you know an assumption is necessary - if when it is negated the argument is like, "wtf?"

(3) This is not the right way to do a conditional negation:

However, if I negate A --> B, which becomes
A --> ~B

The right way to do a conditional negation (like A-->B) would actually be ~(A-->B). In other words, "A doesn't necessarily entail B." Just because it is ~(A-->B) doesn't exactly mean that A --> NOT B. You dig?

While I am at it...

(A): I have no idea what impartiality has to do with anything here.

(B): Not necessary. Maybe a great novelists has powers of observation/analysis. After all, these are supposed to HELP the novelists right?

(C): Same as (A). Also, we don't know WHAT makes novelists great nor do we need to know what does. We need to know what is necessary for a great novelist.

(E): So what? Maybe they can; maybe not. We need to know how this relates to being "great."

[emily315]

Thanks for the logical diagramming, super helpful~
but a little confused, I initially picked the wrong answer of C without diagramming. But after reading your analysis I understand why the answer is D. But does that mean we have to diagram every time we encounter a question like this? Would the time be even enough?

[JosephV]

Thanks for the logical diagramming, super helpful~
but a little confused, I initially picked the wrong answer of C without diagramming. But after reading your analysis I understand why the answer is D. But does that mean we have to diagram every time we encounter a question like this? Would the time be even enough?

In the beginning of your studying for the LSAT, TAKE YOUR TIME and diagram as much as you want (or need, whichever is greater ). Eventually you will become good enough to where your brain will be able to handle the relationships without the need to diagram always. However, this takes time to acquire.

On the test, no way will you have enough time to diagram everything that can be diagrammed. Be judicious about what's worth the extra time to put down on paper. Thirty-five minutes is not that much time.