LSAT 90 - Section 4 - Question 12

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.