Logical reasoning PrepTest 156 · Section 4 · Question 11

This answer choice might strengthen the argument, but it isn't necessary to the argument. Requiring major changes to international law is definitely an impediment to reaching a comprehensive solution to pollution, so this supports the author's belief that there will be no such solution.

However, this isn't necessary to the argument. The author doesn't reason that nations would only be willing to make minor changes to international law. Instead, the author reasons that nations won't agree to any law — major or minor — that requires the nations to give up power over their industries. Even if a solution requires only minor changes to international law, nations may still not agree to the solution if it requires the nation to cede control of its industries.

Alternatively, this is the argument we'd make if we used the backup plan (note that we simplified and negated this answer choice):

"If most parties do not willingly follow a law, then the law won't work. Most nations will not willingly give up power over their industries. But, a comprehensive solution to pollution would not require major changes in international law. So, there may be an international solution to pollution."

This doesn't read like a well-written, cogent argument. The part that follows "But" doesn't contradict or challenge anything that came before it. So, even though the part that follows "But" supports the conclusion, inserting it into the argument creates a jarring and awkward transition. This often happens when the answer choice is not a necessary premise.

No matter which approach we use, we can confidently cross off (A).

As we anticipated, this answer choice strengthens the argument by establishing that any law that could solve pollution would require nations to give up power over their industries. This strengthens the argument by showing that we can connect the two premises. To trigger the first premise's "if" condition, we need to know that most nations will not willingly follow a law that attempts to solve pollution. The second premise tells us that most nations won't willingly give up power over their industries. So, this answer choice establishes that any law that attempts to solve pollution would require some nations to give up power over their own industries, which means that these nations would not follow any pollution-directed law. And if nations don't follow these laws, the laws will be futile, and there will probably not be a comprehensive international solution to pollution.

We also need to know this to draw the conclusion. If laws that attempted to solve pollution didn't require nations to give up power over their industries, then nations might agree to these laws. And if nations agree to these laws that attempt to solve pollution, then there may be an comprehensive international solution to pollution. Since the argument falls apart if we deny this answer choice, we can be confident that the answer choice is a necessary premise.

Alternatively, we can also evaluate this answer choice using the backup plan. Here's the argument we'd make if we used the backup plan (note that we simplified and negated this answer choice to make this easier to read):

"If most parties do not willingly follow a law, then the law won't work. Most nations will not willingly give up power over their industries. But, comprehensive international solutions to pollution would not require some nations to give up power over their industries. So, there may be an international solution to pollution."

This makes sense. Unlike (A) (or the following answer choices), the part that follows "But" explicitly challenges the premises that come before it. The part that follows "But" shows that nations may be willing to follow comprehensive international solutions to pollution, as these solutions will not require nations to do something the nations refuse to do. So, as the conclusion states, there may be an international solution to pollution.

Therefore, no matter which approach we used, we can be confident that (B) is the correct answer.

This answer choice doesn't strengthen the argument. Still, this is a popular answer choice — probably because it negates the conditions of an "if-then" statement that would strengthen this argument.

The claim that "If most nations are not willing to abide by international law, then there could not be a comprehensive solution to the problem of pollution" would strengthen this argument. However, this answer choice removes the "nots" in the "if" and "then" conditions. So, the answer choice, as written, doesn't strengthen the argument. The answer choice as written can only help us conclude that there could be a comprehensive solution to pollution (remember, we can only make valid conclusions about "then" conditions). The answer choice can't help us conclude that there will not be a comprehensive solution to pollution.

Alternatively, this is the argument we'd make if we used the backup plan (note that we simplified and negated this answer choice):

"If most parties do not willingly follow a law, then the law won't work. Most nations will not willingly give up power over their industries. But, even if most nations were willing to abide by international law, there still would not be a comprehensive solution to pollution. So, there may be an international solution to pollution."

This doesn't make any sense. The "But" part doesn't contradict or challenge the premises that came before it. Moreover, the "But" part suggests that there will not be a comprehensive solution to pollution, weakening the claim in the conclusion.

No matter which approach we use, we can confidently cross off (C).

This answer choice doesn't strengthen the argument. If anything, this may weaken the argument by suggesting that an international solution to pollution would only require the cooperation of relatively few nations. That at least seems less challenging than a solution that requires the cooperation of every nation. Since this answer choice doesn't strengthen the argument, it's not necessary to the argument either.

Alternatively, this is the argument we'd make if we used the backup plan (note that we simplified and negated this answer choice):

"If most parties do not willingly follow a law, then the law won't work. Most nations will not willingly give up power over their industries. But, pollution itself is produced by many nations' industries. So, there may be an international solution to pollution."

This doesn't sound like a well-written, cogent argument. The part that follows "But" doesn't contradict or challenge anything that came before it. Inserting the part that follows "But" creates a jarring and awkward transition in the argument. Moreover, the part that follows "But" shows why achieving an international solution to pollution would be difficult. That weakens the conclusion that there "may be an international solution to pollution."

No matter which approach we use, we can confidently cross off (D).

This answer choice weakens the argument. If international laws concerning pollution do not require nations to give up power over their industries, nations may be willing to follow these international laws. And if nations willingly follow these laws, these laws may solve international pollution. This undermines the author's conclusion that there will be no solution to pollution.

Alternatively, this is the argument we'd make if we used the backup plan (note that we simplified and negated this answer choice):

"If most parties do not willingly follow a law, then the law won't work. Most nations will not willingly give up power over their industries. But, most current international laws concerning pollution require nations to give up power over their own industries. So, there may be an international solution to pollution."

This argument doesn't make any sense. The part that follows "But" doesn't contradict or challenge anything that came before it. So, inserting the part that follows "But" creates a jarring and awkward transition in the argument. Moreover, the first two premises and the part that follows "But" suggest that nations will not follow laws concerning pollution, which means that these laws won't work. That strongly suggests that there will not be an international solution to pollution.

No matter which approach we use, we can confidently cross off (E).