#17 - Meteorologist: Heavy downpours are likely to become

[Administrator]

Complete Question Explanation

Method of Reasoning—AP, CE. The correct answer choice is (D)

The argument is structured as follows:

• Premise (1): A warm atmosphere heats the oceans, leading to faster evaporation, which forms rain clouds more quickly.
  
  Premise (2): Warmer atmosphere also holds more moisture, resulting in larger clouds.
  
  Premise (3): As water vapor in larger clouds condenses, heavier downpours are more likely to occur.
  
  Conclusion: Heavy downpours are likely to become more frequent if Earth’s atmosphere becomes significantly warmer.

Premise (1) introduces the following causal relationship:

• Cause Effect/Cause Effect/Cause Effect
  
  Warm air Oceans warm up Faster evaporation Rain clouds form more quickly
  
  Premises (2) and (3) present an analogous causal relationship, where an identical cause (warm air) produces a similar effect (more rain) in a different way:
  
  Cause Effect/Cause Effect
  
  Warm air Larger clouds Heavier downpours

Both causal chains support the prediction that heavy downpours are likely to become more frequent if Earth’s atmosphere becomes significantly warmer. This prediction, therefore, is the main conclusion of the argument. Like many arguments in Method—AP questions, the conclusion is in the first sentence. Because most test-takers expect the conclusion to appear there, test-makers will probably not ask you to identify it—that would be a relatively simple task. The statement referenced in the question stem (“as water vapor in larger clouds condenses, heavier downpours are more likely to result”) is clearly a premise used to support the main conclusion. This prephrase agrees with answer choice (D).

Because the argument structure in Method—AP questions tends to be more complex than usual, it is critical to identify each argument part correctly and understand how they relate to each other before attacking the answer choices. You must learn to do this without necessarily relying on premise or conclusion indicators to give you a clue, as such indicators will not always be provided.

Answer choice (A): This answer can be immediately eliminated, because the argument’s main conclusion is in the first sentence of the stimulus.

Answer choice (B): This answer choice can also be eliminated, because the argument’s main conclusion is in the first sentence of the stimulus.

Answer choice (C): This answer choice is incorrect, because it describes the function of an “intermediate” conclusion. No such conclusion is present in the stimulus. Since each of the two causal chains supports the conclusion independently, the statement in question is only a premise: its function is to support the conclusion, but no other statement is intended to support it.

Answer choice (D): This is the correct answer choice. The statement in question is used to support the only conclusion of the argument, because it provides a causal explanation for the phenomenon described in the conclusion.

Answer choice (E): This answer choice contains a self-contradiction. The first part of it is exactly on point, but the second part contradicts the first. If the statement in question provides a causal explanation of the phenomenon described in the conclusion, then that statement must also be intended to provide support for that conclusion.

[avengingangel]

The explanation here says "Both causal chains support the prediction that heavy downpours are likely to become more frequent if Earth’s atmosphere becomes significantly warmer." -- how is that so? The second causal chain only supports that heavier downpours will more likely result, not that heavy downpours will happen more frequently (the main conclusion). That's why I chose E (first) and then C. The argument does (partly) support the statement referenced, but isn't really too relevant to the overall conclusion.

[Emily Haney-Caron]

Hi avengingangel,

Take a look at the post above yours for why C and E are wrong, and let us know if you have questions.

I think the problem with your understanding of D is that you're misinterpreting "more likely to result" in the last sentence. That doesn't just mean that the rains that happen will be more likely to be heavy, which seems to be how you're reading it. Instead, it actually means that heavy rains will be more likely (i.e., will happen more often). If I said, "rains will be more likely to result," you would understand that to mean that it will rain more frequently. Adding "heavier" doesn't alter that logic.

I hope that helps!

[avengingangel]

Thanks, that does help, and that is how I was interpreting it. however, still, to *me*, adding "heavier" actually does alter the meaning, though. thanks for explaining.

[JD180]

If you look at the last two sentences:

"A warmer atmosphere also holds more moisture, resulting in larger clouds. In general, as water vapor in larger clouds condenses, heavier downpours are more likely to occur."

Why say "in general"? This is not a common way to connect cause and effect, and I believe this unconventional wording was deliberately used to goad test takers into thinking that that last sentence is a subconclusion. But in being deceptive, isn't it so that the LSAT makers actually have shed light upon something interesting: this really could be a subconclusion:

• Premise: A warmer atmosphere also holds more moisture, resulting in larger clouds.
  
  Subconclusion: In general, as water vapor in larger clouds condenses, heavier downpours are more likely to occur.

This subconclusion then supports the overall conclusion.

This would make answer C correct.

I get the cause and effect angle, but what's wrong with this one? Without biasing myself, they both look equally valid.

[Dave Killoran]

So we have the classic case where there are attractive elements in an answer known to be wrong. My response here is: what do you think LSAC is thinking in saying (D) is correct and (C) is incorrect? What would they say in defense of (D) and in response to your criticism?

By the way, I'm not so certain the "in general" was used to deceive, but because without it the statement is so specific as to be possibly false in a factual sense (outside of this stimulus, I mean). In stimuli that deal with "real world" topics (and not made up ones in countries like Valitania, etc), they do like to use premises that are factually true in the real world. I see that "in general" as attempting to conform to that ideal.

Thanks!

[JD180]

So we have the classic case where there are attractive elements in an answer known to be wrong. My response here is: what do you think LSAC is thinking in saying (D) is correct and (C) is incorrect? What would they say in defense of (D) and in response to your criticism?

By the way, I'm not so certain the "in general" was used to deceive, but because without it the statement is so specific as to be possibly false in a factual sense (outside of this stimulus, I mean). In stimuli that deal with "real world" topics (and not made up ones in countries like Valitania, etc), they do like to use premises that are factually true in the real world. I see that "in general" as attempting to conform to that ideal.

Thanks!

I've thought carefully about it, and I honestly don't know how they would defend against my analysis aside from liking theirs better. I was hoping I was missing something that makes my assessment incorrect.

[Rosepose24]

I am also struggling with making a distinction between C and D. I chose C in my blind review too because I felt that the first two premises do support the statement in question. The first premise under the conclusion explains how you get water vapour in clouds more rapidly. Then the second premise explains how a warm atmosphere leads to LARGER clouds. The statement in question tells me that as you condense the vapour in the large clouds there's a heavier downpour. I believe this because the two lines before it just explained the mechanism by which water is building up MORE QUICKLY in LARGER clouds in a warm atmosphere... that's going to reasonably be more water for a heavier downpour.

So with that understanding, when I read answer choice C I immediately felt it was true that the stimulus was intended to support the line. If I had to choose a purpose it would be so that the line in question itself could be effective in supporting the main conclusion (first line).

D was also a contender for this reason. It is used to support the only conclusion. I felt D was less encompassing as a role description. However in retrospect I see that, if I chose C it might make D true too... and that's an indicator of an incorrect answer. I suppose one reason I should have chosen D then is because its the "minimum correctness" required.
I don't know if this is the correct way to differentiate C and D. It doesn't feel like enough. Also, I can't guarantee that I believe my own explanation enough that I would't just make the same mistake again.

Could you help me understand the differentiating factor that I should have used in timed conditions.

[Robert Carroll]

Rose,

There are always two ways to interpret whether one statement is evidence for another:

1. Does it make sense that one statement be evidence for another?

2. Does the author intend one statement to be evidence for another?

Ultimately, if we're describing the role of something in an argument (Method of Reasoning - Argument Part), describing how an argument was supposed to work (Method of Reasoning), or describing how an argument went wrong (Flaw in the Reasoning), the second question is of primary importance. It doesn't matter what we think could have been done - it matters what the author thinks happened.

With that in mind, we have to ask - does the author intend the second and third sentences to be evidence for the last sentence?

I don't think the author did. When the author says "as water vapor in larger clouds condenses", the statement about condensation comes out of nowhere, so to speak. Nothing in the second and third sentences talks about condensation. Nor do I think the author erroneously thought that he had talked about condensation. Instead, the information in that last sentence seems entirely new, not even intended to be based on the sentences before it. So it's not a conclusion of any kind.

I think a factor that may be confusing here is the distinction between the progression of an argument and the progression of the physical phenomena being described. The last sentence is describing a phenomenon that happens, in part, because of the causal factors in the previous two sentences. But the last sentence isn't true because of that. There's an ambiguity in the word "because". "Because" can be a premise indicator or a causation indicator. I think it's fair to say that the physical process in the last sentence happens because of physical processes in the second and third sentences. But the author is not trying to claim that the proposition expressed by the last sentence is true because of the sentences before, the way a conclusion is true because of its premises.

The distinction has come up before! The following thread discusses a very similar issue: viewtopic.php?f=530&t=2208 I suggest reading all of it!

I want to note that this is not a situation where answer choice (C) makes answer choice (D) true, or vice versa, so this is not a situation where you can eliminate an answer because it makes another answer also correct. Answer choice (C)'s truth would entail that the argument has at least one subconclusion, whereas answer choice (D) would entail that it has only a main conclusion. So answer choice (C) does not make answer choice (D) correct. Instead, you have to look independently at each answer.

Robert Carroll