This is a Parallel Method of Reasoning question.
The stimulus says the railway authority inspector who recently thoroughly checked the tracks testified that they were in good condition. The next claim says, “Thus, since” which means we’re about to get a premise followed by a conclusion. Since the inspector has no bias in the matter (premise), we should thus be suspicious of the newspaper reporter's claims that the tracks are in poor condition (conclusion).
Two people disagree about the condition of the railroad tracks. The argument is that we should believe the inspector, not the reporter. Why? Because the inspector has no bias and said the tracks were in good condition after having thoroughly checked them. The reasoning here is an appeal to authority. Let's now look at the answers and try to match the reasoning above.
Answer Choice (A) says my pottery instructor says that making pottery will not cause repetitive-motion injuries if it is done properly. So far, there seems to be a parallel between the pottery instructor and the inspector. Now we have to find somebody who disagrees and then conclude that we should believe the pottery instructor. But then (A) instead says, “I will probably not get such injuries, for whenever I do pottery, I use the proper techniques that my instructor taught me.” While this argument is fine, it is not analogous to the argument in the stimulus.
Answer Choice (B) says Gardner, a noted paleontologist who has no vested interest in the case, assures us that the alleged dinosaur bones are not old enough to be dinosaurs. Gardner, a relevant expert, is analogous to the inspector. Gardner also has no vested interest in the case, so he has no bias.
(B) goes on to say that we should be skeptical of Penwick's claims to have found dinosaur bones, for Gardner inspected the bones carefully. Gardner’s careful inspection is analogous to the inspector’s thorough check, and Penwick is analogous to the newspaper reporter. And the conclusion is that we should be skeptical of Penwick, which is similar to how we should be suspicious of the reporter. (B) matches the stimulus extremely well. The reasoning here is also one of an appeal to authority.
Answer Choice (C) says the engineer hired by the company that maintains the bridge has examined the bridge and declared it safe. The engineer is a relevant expert who has examined the bridge and declared it safe. While we should be wary of subject matter similarity since LSAT writers like to use that as a trap, so far, (C) is analogous to the stimulus.
But (C) then says that the engineer is the only one to have checked the bridge. This idea is not present in the stimulus. In addition, the disagreement component is missing in (C) too. There is no analogue to the newspaper reporter.
Answer Choice (D) says the reporter who recently interviewed the prime minister said that the prime minister appeared to be in poor health. The paper has opposition leanings, so that is a bias. (D) is already diverging from the stimulus.
If we were to keep the subject matter of (D) but apply the reasoning in the stimulus, we would have to say that the reporter did a careful, thorough check (ideally, we’d change the reporter to a doctor to create the appeal to authority). And since the reporter is from an unbiased newspaper, we should be suspicious of, for example, the prime minister's press secretary, who claims that the prime minister is in good health. The edits above would make (D) better, but (D) does not resemble the stimulus in its current form.
Answer Choice (E) says the snowblower salesperson claims that there will be above-average snowfall this winter, but because the salesperson is biased, we can discount the claim. Since the salesperson is biased, (E) is already ruled out.
If we were to keep the subject matter of (E) but apply the reasoning in the stimulus as we did for (D), we would have to say that the snowblower salesperson recently and thoroughly inspected my snowblower and said that it was in good condition. The salesperson is not biased. Therefore, I should be suspicious of my neighbor's claim that my snowblower is in poor condition. You wouldn’t have the snowblower salesperson offer his opinion on the weather since that’s not within his domain of expertise.
This is a Flaw/Descriptive Weakening question.
The stimulus says that if the proposed air pollution measures were to be implemented, ozone levels in the city's air would be one fifth lower, i.e., 20% lower, than current levels. Since the ozone in our air is currently responsible for $5 billion in health costs (premise), we would spend about a billion dollars less on these ozone-related health costs should the proposal be adopted (conclusion).
We always have two options when approaching Flaw questions. Either we identify the flaw in advance and go hunting for it in the answer choices, or use process of elimination. If you think this argument makes sense, keep an open mind as you go through the answer choices because the correct answer will point out something that you had not considered.
Answer Choice (A) says the argument fails to consider the possibility that other types of pollution not involving ozone might rise, perhaps even producing an overall increase in health costs. Sure, maybe particulate matter pollution or carbon dioxide pollution will rise. But the argument is completely contained to ozone and does not contemplate non-ozone-related health costs. So to criticize it for failure to do that is not a criticism of the logic of the argument.
(A) might be a fair criticism if we were having a discussion about health costs in general. But when we evaluate arguments in Weakening or Flaw/Descriptive Weakening, we have to limit that evaluation to the actual premise and conclusion presented, all of which are limited to ozone here. If (A) flies, then I can also say that the biggest contributor to health costs is heart diseases, not ozone, so we should talk about heart diseases if we really want to reduce health costs.
Correct Answer Choice (B) says the argument presumes, without providing evidence, that ozone-related health costs in the city vary roughly in proportion to ozone levels. This means if you reduce ozone levels by 20%, health costs would also go down by 20%. At a minimum, you should recognize that that is an accurate description of the assumption made. The argument is in fact presuming this, so (B) passes step one of the two-step test.
Now ask yourself if it is in fact reasonable to assume this. It turns out it is not. Ozone levels could generate health costs once the level of ozone passes a certain threshold. So it could be that ozone pollution is negligible until after a critical mass of the pollution has been accumulated, after which it becomes very damaging. If that were the case, then the 20% reduction might bring ozone levels under the threshold, which would result in health benefits of $5 billion. The opposite could also be true. Ozone levels could still be above the threshold even after the reduction, in which case we might not reduce health costs at all.
I am not saying this is how ozone levels actually work, but the point is that because we do not know how they work, we cannot make the naive assumption that the relationship between ozone levels and health care costs is proportional. There are so many other non-proportional relationships. And finally, in reality, the economic concept of diminishing marginal returns cuts against the assumption of proportionality.
Answer Choice (C) says the argument provides no explicit reason for believing that the proposed air pollution measures will in fact be adopted. Like (B), (C) is descriptively accurate. We do not know if the measures will be adopted or not. However, this is not the flaw. The premise says, “if the proposed air pollution measures were to be implemented,” so it is contemplating a hypothetical world. If we adopt it, what would happen?
Answer Choice (D) says the argument attempts to support the conclusion by making an appeal to emotions. The conclusion is supported by an appeal to math, not emotions. We think we would reduce health costs by 20% because the ozone levels will go down by 20%. An argument that did appeal to emotions would say something like “we should adopt the new ozone control measures because Timmy lost his mother to ozone pollution.”
Answer Choice (E) says the argument discusses air pollution to draw attention away from more significant sources of health-related costs. An argument actually guilty of this vulnerability would establish that a more significant source of health cost was, for example, heart disease. And the author would say, have you guys considered air pollution? There is ozone, nitrogen, volatile organic compounds, etc. That is trying to draw attention away from heart disease, which does not happen here.
This is a Necessary Assumption question.
The stimulus says recently discovered clay tablets from southern Egypt date to between 3,300 and 3,200 B.C. Though most of the tablets translated thus far are tax records, one of them appears to contain literary writing. All of this is premise supporting the conclusion.
And the conclusion is that these tablets challenge the widely held belief among historians that the Sumerian civilization in Mesopotamia was the first to create literature. So we used to think that the Sumerians were the first, and somehow these tablets challenge that, meaning the Egyptians predate the Sumerians. If you already spotted this assumption, you can just go hunting for the correct answer. But we’ll use process of elimination here.
Answer Choice (A) says most of the recently discovered tablets that have not yet been translated contain literary writing. So in the entire set of recently discovered tablets, there is a subset that has not yet been translated. And in that subset, most contain literary writing.
We do not need this to be true. We already have one of the tablets that contain literary writing and that is enough. Sure, having more would strengthen this argument, but we are just trying to find the necessary assumption. Running the negation test also helps. Say not most but rather just a few of the tablets contain literary writing. The argument does not fall apart.
Answer Choice (B) says every civilization that has kept tax records has also kept other written records. This is also not necessary. We are only talking about two civilizations, the Egyptian and the Sumerian. Why do we care if some other civilization like the Aztecs kept other written records? What does that have to do with this argument? Egypt still predates, or does not predate, the Sumerians in creating literature.
Correct Answer Choice (C) says historians generally believe that Sumerians did not create literature earlier than 3,300 B.C. This has to be true. Imagine if historians generally believed that the Sumerians did create literature earlier than 3,300 B.C., say 4,000 B.C. That is 6,000 years ago. And now we have this Egyptian tablet from 3,300 B.C., only 5,300 years old at best. How is this supposed to challenge the belief that Sumerians were the first to create literature? The Sumerians still predate the Egyptians by 700 years. That is why (C) is absolutely necessary.
Note that this question could have been way harder. Imagine if one of the other answer choices said historians generally believe that Sumerians first created literature between 2,800 B.C. and 2,700 B.C. This would be a super attractive answer choice. However, while this would certainly help the argument by definitively showing that Egyptian literature is older by about 600 years, it is not necessary. And you can see this is not necessary by changing the dates a bit, say 2,500 and 2,400 B.C. That would also help the argument. So it is not necessary that historians have to believe in the 2,800 to 2,700 B.C. date range.
Answer Choice (D) says some historians are skeptical about the authenticity of recently discovered tablets. This is not necessary. If anything, the skepticism only hurts the credibility of the argument. Necessary Assumption is part of the superset that we call Strengthening.
Answer Choice (E) says the Sumerian civilization arose sometime between 3,300 B.C. and 3,200 B.C. This is also not necessary. What if it instead arose between 2,800 and 2,700 B.C.? Falsifying, or negating, (E) does not ruin the argument. If anything, this version of falsification actually helps the argument. Egypt would clearly predate the Sumerians in this scenario because the Egyptian clay tablet would be dated to be 500 years older than the Sumerian civilization itself.
A
Some scientists have found evidence that the waters off the Pacific coast of North America have grown significantly warmer over the past 15 years.
B
The warming of the waters off the Pacific coast of North America is not a symptom of a more general, global warming caused by human-generated air pollution.
C
The conclusion that the warming of the waters off the Pacific coast of North America is a symptom of a more general, global warming caused by human-generated air pollution is far from justified.
D
The warming of the waters off the Pacific coast of North America may be the result of a natural cycle of ocean temperature changes.
E
If the warming of the waters off the Pacific coast of North America is due to a natural cycle of ocean temperature changes, then it is not a symptom of a more general, global warming caused by human-generated air pollution.
Kendall: But what artifacts a people make is determined largely by the materials available to them.
A
the distinction that Robin makes between two kinds of cultures is illicit
B
it is reasonable to assume that a culture whose artifacts were not durable was nomadic
C
any evidence other than the intended durability of a culture’s artifacts can establish conclusively which of the two kinds of cultures a particular culture was
D
the distinction that Robin makes between the different kinds of cultures is as important as many archaeologists have thought
E
studying a culture’s artifacts can reveal a great deal about the culture
A
The volume of freight shipped by rail can be expected to increase.
B
Increasing reliance on automation means that fewer railroad workers are needed.
C
No reduction in operating costs is predicted for the trucking industry.
D
Operating costs for railroads have been reduced as a result of increased reliance on automation.
E
The chief competitor of railway shipping is shipping by truck.
This is a Most Strongly Supported question.
The stimulus says that in the past, infants who were not breast-fed were fed cow's milk. Then doctors began advising that cow's milk fed to infants should be boiled, as the boiling would sterilize the milk and prevent gastrointestinal infections potentially fatal to infants. And once this advice was widely implemented, there was an alarming increase among infants in the incidence of scurvy, which is caused by vitamin C deficiency. Breast-fed infants, however, did not contract scurvy.
While this is not an ideal experiment, it's what's known as a natural experiment. There are two groups, the "intervention" and "control" groups. The intervention group (boiling cow's milk) exhibited more incidences of scurvy than the control group (breast-fed milk). We suspect that the explanation is that boiling cow's milk was the cause. But how? Why would boiling cow's milk cause the infants to contract scurvy? The stimulus contains another fact: scurvy is caused by vitamin C deficiency. That's a clue about the causal mechanism. Together, the facts (the phenomena) strongly support the hypothesis that boiling cow's milk destroyed vitamin C, which in turn caused scurvy.
Correct Answer Choice (A) says boiled cow's milk makes less vitamin C available to the infant than does the same amount of mother's milk. This is a version of the hypothesis above. That's why it's the right answer. (A) is by no means a “must be true,” but the standard of proof is lower for MSS. You never really reach 100% validity in scientific reasoning anyway. That only happens in formal reasoning.
And notice how similar this is to Resolve Reconcile Explain. (A) would still be correct if this was an RRE question since it would explain the phenomenon in the stimulus. This reveals that the question stem is more or less superficial, and that there is an underlying unity to Logical Reasoning. And here the logic is scientific reasoning. You are presented with a natural experiment that resembles the ideal experiment and asked to come up with a reasonable hypothesis.
What's a natural experiment and why do I put quotations around "control group"? Because natural experiments are less reliable than ideal experiments. That doesn't mean they're not reliable at all. Far from it. Natural experiments can sometimes provide very strong evidence. But they are not ideal because the "control group" didn't control for everything.
Imagine you had an alternative hypothesis, say, the citrus shortage hypothesis. Under that hypothesis, there was a shortage in citrus fruits that just happened to coincide with the intervention (boiling cow's milk). Perhaps it's actually the citrus shortage that caused the increase in scurvy.
Okay, but we can preclude this hypothesis with an ideal experiment. We can run a control group. Hold everything else equal (including access to citrus) and feed the control group breast milk. If they don't develop scurvy, then it can't be the citrus shortage that caused the scurvy. That's kind of like what happened in the natural experiment of the stimulus. The difference is that we have no assurances that the breast-fed babies' exposure to citrus was the same as the intervention babies' exposure. It's possible that breast-fed infants somehow had priority access to oranges. It's just very unlikely. That distance is there, though, in the natural experiment, whereas in the ideal experiment, we have assurances that the control group did in fact control for everything. That's why natural experiments are weaker than ideal ones. How much weaker? That depends in turn on which hypotheses you're trying to eliminate. For the citrus shortage hypothesis, it's highly unlikely that the breast-fed group would have had priority access and, therefore, the natural experiment is not that much weaker than the ideal experiment.
Answer Choice (B) says infants who consume cow's milk that has not been boiled frequently contract potentially fatal gastrointestinal infections. (B) could have been correct if it had said sometimes, potentially, or even in danger of contracting. Doctors recommended the intervention precisely to prevent gastrointestinal infections, so it is a reasonable assumption that they thought of unboiled cow’s milk as an actual risk. But “frequently” is too strong to be supported.
Answer Choice (C) says mother's milk can cause gastrointestinal infections in infants. This is just a mishmash. We do know that unboiled cow's milk potentially can cause gastrointestinal infections, but can mother's milk cause it? Nothing in the stimulus suggests the answer is one way or another.
Answer Choice (D) is really attractive. If you picked (D), you probably read some alternate version of (D) that resembles the following: when doctors advised that cow's milk fed to infants be boiled, they did not know that this intervention would lead to vitamin C deficiency, which then would lead to scurvy.
Then (D) would be pretty well supported. It seems clear that when doctors began advising to boil the milk, they did not anticipate that scurvy would be a consequence. I am guessing they also did not know that infants depended on milk for their vitamin C, because if they had some other source, for example, like orange juice, who cares about the vitamin C in the milk? Just drink your orange juice.
But that is not what (D) says. (D) just says that when doctors advised cow's milk to be boiled, the cause of scurvy was a mystery. This I am not so sure about. It is totally possible that doctors knew the cause of scurvy. Lots of sailors knew vitamin C deficiency was the cause of scurvy for hundreds of years. They just did not think this intervention (boiling cow's milk) would result in vitamin C deficiency and hence scurvy.
Answer Choice (E) says that when doctors advised that cow's milk fed to infants be boiled, most mothers did not breast-feed their infants. We know that when this intervention happened, there were some infants who were drinking cow's milk and some who were breast-fed. But nothing in the stimulus says which set is larger, so (E) is totally unsupported.
This is an RRE question.
The stimulus contains phenomena that seem to be at odds. We are told that the only effective check on grass and brush fires is rain. If the level of rainfall is below normal for an extended period of time, then there are many more such fires.
While the statement above is a conditional claim (below normal rainfall -> more grass and brush fires), it is also an implied comparative claim. The implicit comparison takes place in the phrase “many more” in the necessary condition. Many more than what? Or more accurately, many more than when (because the sufficient condition is about timing)? Answering that question will flesh out the comparison. There are many more such fires when the level of rainfall is below normal for an extended period of time than otherwise. That means compared to when the level of rainfall is normal or above normal. Okay, so less rain, more fire, and more rain, less fire.
At this point we might expect that normal rainfall is better since we want fewer fires. However, we are then told that grass and brush fires cause less financial damage overall during long periods of severe drought than during periods of relatively normal rainfall. (Note that “below-normal rainfall” is a spectrum, and that the stimulus is connecting the very extreme end of this spectrum, drought, to the idea of less financial damage.)
That’s the puzzling phenomena. Why would more fires result in less financial damage? Maybe you are a subject matter expert and can anticipate the answer. But I find that I am generally not familiar enough with the subject to start conjecturing in RRE questions. I usually just go to the answers and use the process of elimination.
Answer Choice (D) is essentially categorizing how fires start and stating that the subset of grass and brush fires that are not caused by human negligence or arson tends to be started by lightning.
We have to make many assumptions in order for this claim to be helpful. First, we have to assume that fires started by lightning are more or less financially damaging than the ones started by arson or negligence, because the distinction above only matters if it can explain the difference in how much financial damage each fire type causes.
But even if there was an empirical answer to which fire is more damaging (maybe studies have shown definitively that fires started by human negligence and arson are the more damaging subtypes), that is still not good enough. Because we then need to additionally assume there is a correlation between the way fires start and periods of rainfall; for example, that people tend to start fires during periods of normal rainfall and lightning tends to strike during droughts. These multiple layers of unreasonable assumptions make (D) very weak.
Answer Choice (A) and (E) are similar cookie-cutter wrong answers in that for RRE questions, we tend to get choices that do not explain the paradox but rather only deepen it. To illustrate this, I am going to intentionally read both of them wrong, or flipped, so that they state the opposite idea.
Answer Choice (A) states that fire departments tend to receive less funding during periods of severe drought than during periods of normal rainfall. Let’s flip this to more funding for now. This then helps us explain why there is less financial damage during droughts—we have more fires, but the fire department has doubled its staff or bought five new fire trucks and is equipped to deal with more fires.
Compare this to periods of normal rainfall, where we have fewer fires, but we also cut funding. We disband the firefighters, sell off all the fire trucks, and Optimus Prime is receiving unemployment benefits. This would explain why there is more financial damage.
As we can see, if we flip (A) from less funding to more funding, it actually does provide an explanation, which is why the way it stands now only deepens the problem. It blocks a potential explanation and exacerbates the apparent paradox.
Answer Choice (E) is similar. (E) states that when vegetation is destroyed in a grass or brush fire, it tends to be replaced naturally by vegetation that is equally if not more flammable. Let’s flip this again and read it as less flammable, the opposite of equally if not more flammable.
Consider a scenario where we have below-normal rainfall and therefore more fires than we would have under normal rainfall. (E) is saying that after the iteration cycles from one fire to the next, vegetation is destroyed, but it comes back as more resilient.
If this is the case, there would be less financial damage since evolution selects against the flammable plants and for the fire-resistant plants. So with each iteration of fires, plants become more fire immune. This would also explain the phenomena. Why is there less damage when there are more fires? It’s because the plants themselves don’t burn well so the fires don’t burn out of control.
Just like (A), however, the way (E) stands right now is saying that vegetation is just as, if not more, flammable. If it is just as flammable, each iteration of fire does not change anything. If it is more flammable, it would make (E) even more problematic, because we would then have a vicious cycle where fires just get bigger and bigger.
Answer Choice (B) is probably the most attractive wrong answer choice. It states that areas subject to grass and brush fires tend to be less densely populated than areas where there are few such fires. We might think that areas with below-normal rainfall have more fires, so this is the area with less people. Areas with normal rainfall have fewer fires, so this is the area with more people. Since less people means less residences, less businesses, etc., we have less financial damage. Similarly, more people would mean more financial damage.
But (B) is not correct. One objection might be that there is a difference between being densely populated and having more people overall. While this is a valid objection, I do not think it is the strongest objection. The much stronger objection is that the analysis we just did above does not make sense.
Essentially, (B) is a comparative claim that compares areas that are prone to fires to areas where there are few such fires. Let’s assume we are looking at the former. We still need to explain why in this given area—with its fixed, less dense population—we have more financial damage when there is normal rainfall and less when there is a drought and therefore more fires.
The same applies for areas that are less prone to fire (i.e., areas where there are few such fires). Since people prefer to live in areas not prone to fires, it is expected that such an area would be more densely populated. But again, even such areas are still subject to variations in rainfall. And we have not explained why there is more financial damage under normal rain conditions and less financial damage under droughts.
(B) baits us to confuse geographically defining an area based on how susceptible it is to fire with how much rainfall a given area receives. It makes no sense to assume that more fire-prone areas always receive below-normal rainfall. Furthermore, if an area is always receiving below-normal rainfall, then that is its normal level of rainfall—it is a desert.
Answer Choice (C) is correct. (C) makes a couple of assumptions, but we have to remember that assumptions live on a spectrum of reasonableness. Both obviously reasonable assumptions and obviously unreasonable assumptions exist, but there is also a vast space between the extremes where an assumption is “kind of reasonable,” more reasonable than the assumptions the other answer choices might require.
(C) states that unusually large, hard-to-control grass and brush fires typically occur only when there is a large amount of vegetation for them to consume. For (C) to be correct, at least two assumptions are required.
One is assuming that there is a causal connection between rainfall and the amount of available vegetation. This assumption is pretty reasonable. You are certainly not going to say vegetable growth is independent of whether there is rain or drought.
The second assumption is that the unusually large and hard-to-control fires are the ones that cause more financial damage. This also sounds fairly reasonable.
With these two assumptions, (C) explains our stimulus. The first assumption distinguishes between the amount of plant material available to burn. Although there are more fires in drought conditions, there is also less vegetation to burn so the result is more but smaller fires, whereas under normal rainfall conditions, although there are fewer fires, there is also more to burn so the result is larger fires. Now the second assumption comes in. Large, hard-to-control fires cause more financial damage.
You might still be unhappy with (C). If you are, it’s probably because in the easier RRE questions, the correct answers do not ask you to make additional assumptions. But in harder RRE questions (or harder Weakening and Strengthening questions), the correct answers do require reasonable assumptions, ones more reasonable than whatever assumption we needed to make for the other answer choices. Remembering this will help you get more of these questions right.
This is a Parallel Method of Reasoning question.
The stimulus says the railway authority inspector who recently thoroughly checked the tracks testified that they were in good condition. The next claim says, “Thus, since” which means we’re about to get a premise followed by a conclusion. Since the inspector has no bias in the matter (premise), we should thus be suspicious of the newspaper reporter's claims that the tracks are in poor condition (conclusion).
Two people disagree about the condition of the railroad tracks. The argument is that we should believe the inspector, not the reporter. Why? Because the inspector has no bias and said the tracks were in good condition after having thoroughly checked them. The reasoning here is an appeal to authority. Let's now look at the answers and try to match the reasoning above.
Answer Choice (A) says my pottery instructor says that making pottery will not cause repetitive-motion injuries if it is done properly. So far, there seems to be a parallel between the pottery instructor and the inspector. Now we have to find somebody who disagrees and then conclude that we should believe the pottery instructor. But then (A) instead says, “I will probably not get such injuries, for whenever I do pottery, I use the proper techniques that my instructor taught me.” While this argument is fine, it is not analogous to the argument in the stimulus.
Answer Choice (B) says Gardner, a noted paleontologist who has no vested interest in the case, assures us that the alleged dinosaur bones are not old enough to be dinosaurs. Gardner, a relevant expert, is analogous to the inspector. Gardner also has no vested interest in the case, so he has no bias.
(B) goes on to say that we should be skeptical of Penwick's claims to have found dinosaur bones, for Gardner inspected the bones carefully. Gardner’s careful inspection is analogous to the inspector’s thorough check, and Penwick is analogous to the newspaper reporter. And the conclusion is that we should be skeptical of Penwick, which is similar to how we should be suspicious of the reporter. (B) matches the stimulus extremely well. The reasoning here is also one of an appeal to authority.
Answer Choice (C) says the engineer hired by the company that maintains the bridge has examined the bridge and declared it safe. The engineer is a relevant expert who has examined the bridge and declared it safe. While we should be wary of subject matter similarity since LSAT writers like to use that as a trap, so far, (C) is analogous to the stimulus.
But (C) then says that the engineer is the only one to have checked the bridge. This idea is not present in the stimulus. In addition, the disagreement component is missing in (C) too. There is no analogue to the newspaper reporter.
Answer Choice (D) says the reporter who recently interviewed the prime minister said that the prime minister appeared to be in poor health. The paper has opposition leanings, so that is a bias. (D) is already diverging from the stimulus.
If we were to keep the subject matter of (D) but apply the reasoning in the stimulus, we would have to say that the reporter did a careful, thorough check (ideally, we’d change the reporter to a doctor to create the appeal to authority). And since the reporter is from an unbiased newspaper, we should be suspicious of, for example, the prime minister's press secretary, who claims that the prime minister is in good health. The edits above would make (D) better, but (D) does not resemble the stimulus in its current form.
Answer Choice (E) says the snowblower salesperson claims that there will be above-average snowfall this winter, but because the salesperson is biased, we can discount the claim. Since the salesperson is biased, (E) is already ruled out.
If we were to keep the subject matter of (E) but apply the reasoning in the stimulus as we did for (D), we would have to say that the snowblower salesperson recently and thoroughly inspected my snowblower and said that it was in good condition. The salesperson is not biased. Therefore, I should be suspicious of my neighbor's claim that my snowblower is in poor condition. You wouldn’t have the snowblower salesperson offer his opinion on the weather since that’s not within his domain of expertise.
This is a Weakening question.
In Weakening questions, we take away the support that the premise provides to the conclusion. We usually do this by identifying an assumption in the argument and stating the opposite of that assumption.
The stimulus says that the government’s tax collection agency (i.e., IRS) has not followed through on its plan, announced a year ago, to crack down on violations of corporate income tax law. This is the conclusion. And the premise for this conclusion is that audits are the primary tool for detecting such violations, and over the past year, not a single audit of corporate income tax returns has been completed.
So far, it sounds like the IRS is doing a pretty bad job following through on its plan. But wait, we’re not supposed to like this argument. We’re supposed to identify where this argument is weak.
If you feel this way at the end of a stimulus, that’s okay. Just remind yourself to be skeptical and then look at the answer choices. Perhaps one of them will clue you in on where the argument is weak.
Answer Choice (A) says the plan to crack down on violations of corporate income tax law is part of a broader campaign against corporate misconduct. So who cares if some other agencies like the SEC or the FTC also announced their plans? We are discussing whether the IRS followed through on its plan, so (A) is entirely irrelevant.
Answer Choice (B) says the number of personal income tax returns audited over the past year is greater than in previous years. There is a big difference between corporate income tax and personal income tax, which makes (B) irrelevant. While (B) might become more relevant if you misread personal as corporate, (B) is useless as it currently stands.
Answer Choice (C) says most audits of corporate income tax returns do not reveal any significant violations. All (C) tells us is that, of the set of all audits of corporate income tax returns, only a minority revealed significant violations. How does this information even fit into the stimulus? It still stands that zero audits were completed last year.
Answer Choice (D) says it generally takes longer than one year to complete an audit of a corporate income tax return. This reveals the naive assumption the argument made. For example, if it only takes three months to complete an audit and the IRS had completed zero audits, we can say it did not follow through on its plan. However, if it takes more than a year to complete an audit, the IRS could have followed through on its plan by having initiated many audits in the past year even though none were completed.
While the information in (D) does not challenge the truth of the premise, it changes its significance. The fact that the IRS had completed zero audits now has no power to show that it did not follow through on its plan. This a quintessential correct answer choice in a Weakening question. (D) does not challenge the truth of the premise or the conclusion, but it does weaken the support that the premise gives to the conclusion.
Answer Choice (E) says that over the last five years, fewer audits of corporate income tax returns have been completed than in the preceding five years. (E) might relate to the argument by revealing the reason why the IRS said they were going to crack down on tax violations. They might have realized that they are auditing less than they used to and decided to pick up the pace. But even so, this does not weaken the argument.