Although we could replace the beautiful—but dilapidated

EXPLANATION FROM POWER PREP

The argument in the stimulus appears as follows:

Premise: Although we could replace the beautiful—but dilapidated—old bridge across Black River with a concrete skyway,

Conclusion: we should instead replace it with a cable bridge

Premise: even though this would be more expensive than building a concrete skyway.

Premise: The extra cost is clearly justified by the importance of maintaining the beauty of our river crossing.

Since you are asked to identify an assumption on which the argument depends, you must look for any leaps in the reasoning (Supporters), or any ideas that threaten the stimulus that must be rejected (Defenders).

As in any Assumption question, consider the conclusion: we should replace the old bridge with a cable bridge. Why is that the case? The author states that we must do so despite the expense in order to maintain the beauty of the river crossing (this reasoning is extremely questionable because it fails to consider that a properly designed concrete skyway might be just as beautiful as a cable bridge). Most students, when examining this stimulus, see that connection and realize that the author has assumed that the cable bridge will be more attractive. Using that prephrase, they are then able to effectively dispose of this question by accelerating through this problem and selecting (E).

If you did not see that connection after reading the stimulus, do not forget to use the Assumption Negation Technique, which can help confirm that you have selected the correct answer.

Answer choice (A): The author does not see cost as a major issue, so the author is not committed to the idea that the cable bridge is not more costly to maintain.

If you are unconvinced, negate the answer, and consider how the author would respond to the negation. Even if the cable bridge were more expensive to maintain, the author of this argument might still insist that the beauty is worth the cost, so this response is not critical to the argument.

Answer choice (B): The argument cannot depend on an assumption that is contradictory to the argument’s premises (cost advantage is most certainly a practical advantage), so this response is definitely wrong. Furthermore, even allowing for some leeway with this response, the author might not care about practical concerns.

Answer choice (C): This is the most attractive incorrect answer. However, “beauty” in this stimulus is only tied to a concept the author wishes to maintain, and the author is not tied to a specific level of beauty. For example, preservation implies a reasonably equal level of beauty, and technically the author’s argument allows for the possibility that preservation of the site’s current level of beauty is not essential. The author could accept some lower standard of beauty, and therefore still choose to advocate a more beautiful bridge.

From an Assumption Negation Technique standpoint, the correct negation of this answer is: “The beauty of the river crossing does not necessarily need to be preserved.” In response to this negation, the author could note that while it doesn’t need to be preserved, there are still benefits to having some level of beauty present, and that therefore the cable bridge is still the preferred choice.

Answer choice (D): This answer choice trades on how people would react to the cable bridge, but popular opinion is not a good method of proof or disproof on the LSAT. Even if most people believed the money poorly spent, the money could still be well spent. Also, people could simply have no particular opinion at all, and that would not damage the argument. In the realm of argumentation, opinions mean little and prove less. Search for an answer with a basis in fact.

Answer choice (E): This is the correct answer choice. If you are uncertain as to whether this answer is correct, use the Assumption Negation Technique. If the cable bridge is not more beautiful than the concrete bridge, how is the author’s argument affected? Because beauty was a driving factor in advocating a cable bridge, the negation of this answer choice would severely weaken the author’s argument, and hence this answer is correct.

Mechanistically, notice that “beauty” appears in one of the premises and nowhere else, and “cable bridge” appears in the conclusion but nowhere else. Not surprisingly, these ideas are linked in this assumption of the argument.