Q6 - Although we could replace

[unmrkny]

I have a quick question: I correctly chose E but want know why D is wrong (just to get most out of it!) Is D wrong because people's opinion doesn't matter?

Thanks in advance!

[ManhattanPrepLSAT1]

Notice that answer choice (D) doesn't relate to the evidence at all. in fact it simply supports the conclusion without relying on the evidence. We're asked to find an assumption of the argument, which means we need to find the gap in the reasoning between the evidence and the conclusion.

You're correct in that whether people think the extra money was well spent, and whether the extra money was actually well spent are two separate issues. In fact that's a common flaw in the LR section. Just because someone "thinks" or "believes" something, doesn't mean that it's true. Also, keep in mind the difference between those who view the bridge and those who pay for it. Think about all the people who view the Golden Gate bridge in San Francisco each year, and yet not all them actually responsible for paying for it.

I hope that helps!

[unmrkny]

Thanks a lot!

[ss_8185]

Why is C wrong? If that choice is negated and you don't have to preserve the beauty of river crossing then it wouldn't make sense to suggest the additional cost of a cable bridge.

[goriano]

Why is C wrong? If that choice is negated and you don't have to preserve the beauty of river crossing then it wouldn't make sense to suggest the additional cost of a cable bridge.

I have the same question and was debating between (C) and (E). Negating (C) we get "The beauty of the river crossing need not be preserved." If this is true, how can the extra cost of the cable bridge be justified?

[monster_omiga]

Why is C wrong? If that choice is negated and you don't have to preserve the beauty of river crossing then it wouldn't make sense to suggest the additional cost of a cable bridge.

I have the same question and was debating between (C) and (E). Negating (C) we get "The beauty of the river crossing need not be preserved." If this is true, how can the extra cost of the cable bridge be justified?

Exactly the same question. Any help?

[eunjung.shin]

Here is what I think..

Premise: cable bridge costs more than the concrete skyway, but the extra cost is justified b/c we have to keep it beautiful.

Con: we should replace the old bridge with the cable bridge.

Assumption: cable bridge is more beautiful than the concrete.

The reason C is wrong is C is not absolutely necessary for the conclusion to be true. (look at the question stem, it is asking for the necesarry assumption rather than a sufficient) and it is not connecting the missing link between the premise and the con. I think C strengthens but it is not necessary. If you negate C, it reads "the beauty of the river crossing must not be preserved", the arg says the extra cost is justified by the importance of maintaining the beauty. But even if beauty doesnt need to be preserved, there could be other criteria that is not mentioned but can justify the cost or justify the reason to replace with the cable bridge. It doesnt kill the argument. That is why C is not necessary for the conclusion to be true.

However, if E is not true, which means if cable bridge is not more beautiful than the concrete one, then the conclusion falls apart.

Hope that helps!

[ManhattanPrepLSAT1]

Great discussion everyone!

What's an assumption? An assumption is the unspoken link between the evidence and the conclusion.

This argument concludes that we should replace the bridge with a cable bridge rather than a concrete skyway. Why? Because it's important to maintain the beauty of the river crossing.

Answer choice (C) simply repeats the evidence (though maybe more forcefully). Answer choice (C) is not an assumption, but rather a premise.

Hope that helps!

[austindyoung]

So, this one really got to me- then I thought about it and I hope it helps others out too. --Also, I'm a little wary of posting after a Geek has already wrote something- however this is just even more explication that I hope is relevant!

So, here is why I was confused with (C) and (E).

I realized that (C) was the sufficient (premise) part of the argument- and that negating it did not destroy the Conclusion that the cable bridge should be build instead of the concrete skyway.

The negation of the sufficient condition still allows the necessary one to remain intact. By negating (C), like eunjung.shin stated, the author's conclusion can still remain- by appealing to other factors, besides beauty - and still appeal to beauty, I guess, since it is not part of his explicit conclusion (necessary condition).

But then I wondered: Why can we negate something about beauty in (C), and the argument still remains intact, but when we negate (E)- which also involves beauty, the argument falls apart? Beauty isn't mentioned in author's conclusion- so how do we differentiate (E) with (C)?

Then, I realized the error of my ways.

This Necessary assumption Q deals with a missing link. They all do, however this link is explicit in the problem. Other protect the conclusion differently, from competing ideas that could weaken the conclusion... I hope that makes sense... I guess this one is a little more tricky, because we are used to the missing link pattern for Sufficient Assumption Qs, but they definitely pop up in Necessary Qs as well.

Anyway:

Assumptions are supposed to protect the conclusion.

So, when we negate (C), the author's conclusion is still there. He could say, "Well, we still should build the cable bridge."

However, (E) is necessary because the author is assuming that the cable bridge is more aesthetically pleasing that the concrete skyway. If we negate (E) -building a cable bridge is NOT more aesthetically pleasing than a concrete skyway- the argument does fall apart.

But why? Why can't we, as we did in (C), state that the author can appeal to something else and state, "Well, we still should build the cable bridge."?

This comes with looking at the argument holistically- which can be difficult when sorting out the CORE, which requires us to look at the argument's constituent parts.

However- if (E) is false, then the argument's premise is sufficient for denying the conclusion. If (E) is false, we can ask, "Well then why should we build the cable bridge?" And there is nothing else to appeal to, within the given text.

If we add the negation of (E) to the argument, it does not follow. If we add (E), the conclusion is protected by the necessary assumption.


I hope that helped. If I'm wrong in any way, more than happy to be corrected.

[nflamel69]

Matt hit it right on the spot that C doesn't connect the premise to the conclusion. For those who are still uncertain about C, think it this way, at least it helped me. C is wrong simply because does the beauty have to be "must be preserved"? Even if it's not a must, can the beauty be used to justify the cost? Could be, right? In other words, the necessity of beauty is not required, since we already know from the premise that it is important to justify the cost.

[guolan27]

The first sentence states that the old bridge is beautiful but dilapidated and should be replaced with the more expensive cable bridge in order to maintain the beauty of the river crossing. Thus, it has to be assumed that the cable bridge is more aesthetically pleasing than the concrete skyway. Also, the last sentence already tells us that it is important to maintain the beauty of the river crossing, therefore answer choice (C) can not be the assumption we are looking for. Remember an assumption is not explicitly stated in the argument.

[disguise_sky]

Hello everyone.
So the justification for the choice of a cable bridge is that it maintains the beauty. Does it mean that one bridge choice has to be more beautiful than the other bridge choice to be able to "maintain the beauty"? So if they are equally beautiful, neither of them can maintain the beauty?
I am confused where can we derive the necessity of the comparison on beauty between the concrete bridge and the cable bridge. Can anyone help me with it? Many thanks!

[Djkrd92]

Hey everyone,

Choice (C) shows a commonly used answer that LSAC uses in necessary questions. It's simply TOO strong to be necessary.

If you look at the stimulus, the conclusion is that "we should replace it with a cable bridge even though it would be more expensive," and it is supported by the premise, "justified by the importance of maintaining the beauty."

Look carefully how it said "IMPORTANCE" and not "NECESSITY." If we negate choice (C), it reads "the beauty of the river crossing DOES NOT HAVE to be preserved." It's NOT "It must not be preserved." So be careful about that. You can see now that even when we negate choice C, the argument still holds. The river crossing doesn't have the be preserved, but we should still use the cable bridge because it is IMPORTANT that we preserve it." See? It's not absolutely positively necessary that we preserve it, but it would be nice if we do. The argument says exactly that.

If you negate choice (E) to "Building a cable bridge across Black River would not produce a more aesthetically pleasing result than building a concrete skyway," you have absolutely no reason to build a cable bridge. Why? Because it's too costly for NO reason whatsoever according to the stimulus. Remember, the conclusion is that we should build a cable bridge even though its more expensive," BECAUSE "it's important that we preserve the river crossing." That's it. No more premises. So if the cable bridge is NOT any better, why pay more for it? It ruins the argument.

Hope this helps!