Driving the steep road to the mountain-top Inca ruins of Machu Picchu

Hello, Ujaswin. You put your finger on the exact conclusion of the argument, but your own conclusion, which I have highlighted in red above, deviated from the correct line of logic. You are only supposing or assuming that the cable car will cause such harm. Maybe it will not. We simply do not know one way or the other, but the argument falls into a logical trouble zone when it asserts, well, the exact conclusion you outlined above: installation of the cable car is certain to result in harm to the ruins.

In the interest of helping the community, I will offer my thoughts on each of the answers below.

Since we are looking to call into question or weaken the argument, we have to be careful to stick to the exact logic of the argument. The only certainty given in the argument is that

the Peruvian government is installing a cable car.

The conclusion that follows just after is speculation:

[installation of a cable car will] result in a large increase in tourism.

This could be true, but we cannot be certain of this influx of tourists. Thus, the premise that follows is already on shaky ground:

the presence of large numbers of tourists tends to accelerate the deterioration of a site

Again, we cannot be certain that tourists will suddenly turn up in droves, but I also want to point out how tends to in the middle of the premise also does not lead to a certainty. I can say that during the monsoon season in a certain area, it tends to rain quite frequently, but is not the same as saying that it will or must rain. That is, I cannot wake up in such a place and predict that it will rain with 100 percent certainty even if it is probable. And finally, we get the conclusion:

installation of the cable car is certain to result in harm to the ruins

We already know by now that this conclusion is premature, but what do the answer choices have in store for us?

Analysis: What does the original resident population of Incas have to do with the argument at all? The word original is troubling me here. Are we to understand that this tag refers to the Incas of some pre-Columbian time? Are we to then extend our reasoning that if such an original population did not destroy Machu Picchu, then neither will a smaller group of people? For one thing, the indigenous peoples were not skirting up the mountain in cable cars; for another, as a test-taking note, whenever you find yourself really stretching to justify an answer in CR, it is almost always going to prove incorrect. There is a linear line of logic to follow, and this one steers off-course pretty fast. There is nothing to put a dent in the argument that installing the cable car will cause damage to the ruins. That is, the argument could remain intact. Red light.

Analysis: If anything, this answer makes it sound as if the outcome were more definite. The use of potentially damaging heavy machinery at the site sounds pretty ominous. Although, once again, the outcome is not a certainty, the argument is not being dismantled at all by this consideration. Red light.

Analysis: Great, but this could play right into the logic of the argument. Maybe more people will visit once the cable car makes the site more accessible. On the other hand, maybe more people will not visit, but the installation of the cable car could still cause harm to the site. This information has no bearing on the argument one way or the other. Red light.

Analysis: This is a tempting distraction, since a different factor, natural weathering, is said to continue to be a more significant cause of the deterioration of the site. In other words, tourists are apparently not the primary destructive force. The problem is that the argument does not rank causes of deterioration. It is based instead on the installation of a cable car at the site, an action that will drive in more tourists, who, in turn, will accelerate the deterioration of Machu Picchu. The argument is not affected if weather proves more destructive than foot traffic. Red light.

Analysis: Now we are swapping out one mode of transportation with another, but it is the tour buses that at present do significant damage to the site. In other words, we know or can be certain only that buses are damaging the site, not that the cable car will be when it replaces the buses. Such a conclusion is pure speculation, weakening the certain part of the conclusion. Green light.

I had a lot of fun with this one. I, too, would like to know the source of the question, since whatever source it comes from does mimic an official question quite well, a feat that many third-party sources do not achieve.

If anyone has any further questions, feel free to post a response. Good luck with your studies.

- Andrew