45.4.6 Although we could replace

Accounts Playable

I watched JY's video on this one (http://7sage.com/lsat_explanations/lsat-45-section-4-question-06/), but I don't understand his reasoning for eliminating answer choice C. During the exam, I couldn't distinguish between C and E. I know that E is a necessary assumption, but how is C not as well? If the beauty of the river crossing must not be preserved, then doesn't this completely wreck the argument? Why would the extra cost of the cable bridge be justified if the beauty of the crossing must not be preserved?

The Last Emperor

I think that the idea behind rejecting C is that it comes close but doesn't not quite reach the desired answer level . JY mentioned the "must" part, but I also was not fully convinced. By doing a blind review, I came to the conclusion that even though the "beauty of the river crossing must be preserved (C), nothing states that building a new concrete skyway would compromise the beauty of the river. Whereas choice E, makes the distinction in that the cable bridge is better than the skyway because it is aesthetically pleasing (vague meaning for beauty).

c.janson35

If answer choice C said instead "the beauty of the river crossing should be preserved" then I think it would be a stronger argument that it's a necessary assumption. But as it stands with "must" it doesn't seem necessary. Negating C, we come up with "the beauty of the river does not need to be preserved". But just because something isn't necessary doesn't mean it still isn't desirable. The author may recognize this fact, that the beauty doesn't **have** to be preserved, but nonetheless still maintain his position that the cable bridge is preferable because it would allow the beauty to be preserved.

Hope this helps!

Jonathan Wang

c.janson is correct. This is a perfect example of why JY teaches the negation test as "It is not the case that...", and how just sticking the word "not" into the statement to negate it will get you in trouble. "Must not" is the opposite of "must", not the negation.