Q17 - Climatologists believe they know why

[noah]

Preptest 44, October 2004 LSAT answers

The conclusion of this argument is that the cause of ice ages is the earth passing through cosmic dust clouds, which in turn is caused by fluctuations in the Earth's orbit around the sun. (I always thought that!). The climatologists base their argument on the fact that the occurrences of ice ages, starting 800,000 years ago has coincided with fluctuations in the Earth's orbit around the sun. The climatologists note that the clouds would have to be quite dense for this all to be true.

We're looking for an answer that does not strengthen the argument. (D) introduces the fact that cosmic rock periodically enters the earth's atmosphere and kicks up dust. This weakens the argument in that it raises the possibility that there's another reason for the dust that causes the ice ages: it's the cosmic rock dust, not the fluctuations! However, there are problems with this answer as a weakener in that we'd need to do a lot of "work" to make (D) weaken: periodically would have to coincide with the ice-age cycles, the dust that is kicked up would have to be dense, and would have to reach the atmosphere - though, as one poster below suggests, perhaps we should consider anything above the earth's surface to be atmosphere! But, let's not lose sight of what we're looking for - something that does not strengthen, and regardless of whether (D) weakens or is neutral, it doesn't strengthen the argument.

(A) supports the connection between the clouds and the ice ages: of course there were no ice ages before then, we didn't float through any dust clouds!
(B) establishes that there is indeed a dense cloud around the sun, something the climatologists conceded needed to be true -- and answers the nagging question of why the ice ages only began in the year 800,000 b.c.e.
(C) supports the idea that dust causes a lower temperature, strengthening the argument.
(E) provides more evidence that Earth passed through a cosmic cloud around the time of the ice age.

Edit for clarity: thanks to interestedintacos!

[mrudula_2005]

I thought "B" was the correct answer because I thought that the climatologists hypothesized that the fluctuations of the Earth's orbit around the Sun were what were responsible for the clouds of cosmic dust entering the atmosphere (and that, therefore, B's attributing of the dense cosmic dust cloud to 2 large asteroids would not strengthen the argument)...how did you know that that was not necessarily the case?/What am I misreading?

I thought that when the climatologists said "when the fluctuations occur, Earth passes through clouds of cosmic dust that enter the atmosphere", they necessarily mean the 2 are connected - that there is causality (i.e. the fluctuations creating a cloud of cosmic dust) - i mean, why else would there be a repeated connection between the 2 phenomena?

[noah]

I thought "B" was the correct answer because I thought that the climatologists hypothesized that the fluctuations of the Earth's orbit around the Sun were what were responsible for the clouds of cosmic dust entering the atmosphere (and that, therefore, B's attributing of the dense cosmic dust cloud to 2 large asteroids would not strengthen the argument)...how did you know that that was not necessarily the case?/What am I misreading?

Yes, they do hypothesize that (conclude it), but we're asked to strengthen the argument, and thus the conclusion. We never actually hear that the scientists have evidence that these clouds actually exist. (B) tell us the clouds existed, and that they were dense - which is apparently needed for the clouds to have a cooling effect.

I thought that when the climatologists said "when the fluctuations occur, Earth passes through clouds of cosmic dust that enter the atmosphere", they necessarily mean the 2 are connected - that there is causality (i.e. the fluctuations creating a cloud of cosmic dust) - i mean, why else would there be a repeated connection between the 2 phenomena?

All of that is what the scientists think. Even if we knew that the clouds exist, that they're dense, and that earth passes through them, we actually still would not know if it caused the cold. For all we know, the cold attracts the clouds. We can't assume that two things that are correlated have a specific relationship of causation. Perhaps both events are caused by a third thing - like Zeus sneezing

Sounds like you're not yet set on what your job is with strengthen questions - you're reinforcing the argument, usually by making an assumption explicit, and here, giving evidence to show that the supposed cause actually occurred.

Make sense?

[mrudula_2005]

All of that is what the scientists think. Even if we knew that the clouds exist, that they're dense, and that earth passes through them, we actually still would not know if it caused the cold. For all we know, the cold attracts the clouds. We can't assume that two things that are correlated have a specific relationship of causation. Perhaps both events are caused by a third thing - like Zeus sneezing

Hmm, I do understand that part, but that's not really my issue. What I am hung up on is that for me I thought part of the conclusion was that the fluctuations cause and create the clouds of cosmic dust - so for that reason I thought that B, which attributes the cosmic dust to 2 large asteroids (rather than to fluctuations in the earth's orbit around the sun), would necessarily weaken the argument (since I believed the argument to be saying or at least implying that the fluctuations produce and are responsible for the clouds of cosmic dust). I'm not sure if my issue is coming out clear...

[noah]

Ahh, interesting. The issue here is that (B) does not suggest it wasn't because of the fluctuations, but just confirms that the dust is actually there. And, it confirms that the cloud began around 800,000 years ago - which is when the ice age began. This settles this particular potential weakness: If the dust had been there forever (or, starting say 1,000,000 years ago) then why would the ice ages not have started only in the year 800,000 years ago?

Did that answer your question?

[interestedintacos]

B is wrong because the idea that the fluctuations cause the cosmic dust clouds is based on a distorted reading of the text. The text never says that. The climatologists say that when the fluctuations occur the Earth passes through the clouds of dust. They don't say the fluctuations cause the clouds of dust. What seems more likely is that the dust is there for another reason, for instance the possibility in choice B (the asteroids colliding), and the fluctuations merely lead to a situation where the Earth passes through them. Think about it--the Earth goes off its normal path of orbit around the Sun and then runs into pesky cosmic dust in that particular area around the Sun.

B is a strengthener not just because it says the clouds exist, because that's already stated in the argument ("comsic dust clouds are common") but specifically links particularly dense cosmic dust clouds to the area in question (the Sun's orbit, thus potentially being the clouds we're looking for). We were told the issue of particularly dense clouds existing is uncertain, and this choice shores that up.

I want to point out that D is the correct answer for a different reason than what's stated. D is not just neutral. It's a weakener. The weakness mentioned in the stimulus, again, is that there may not be the "particularly dense" cosmic clouds needed to have such a great effect of creating an ice age. D presents an alternative possibility: that the basic idea may be correct, that dust in Earth's atmosphere dims the sun and causes an ice age, but that this dust actually comes from the Earth's surface (as a result of periodic cosmic rocks) and not from the cosmic dust clouds cited by the Climatologists.

So this choice directly takes advantage of the weakness cited in the stimulus--there might not be cosmic dust clouds dense enough to do the job--well, how about Earth dust then?

I don't think the dust that comes from the Earth's surface counts as the "clouds of cosmic dust" in question. I think this is testing another precise point of reading--seeing whether people will fall for the distortion. The test taker is looking for "cosmic dust" and the test maker gives the test taker cosmic rock and Earth dust. So it's a clever trick.

Other weaknesses could be in play at the same time but I think this hits the main one. I don't think it's too much of a stretch to think, for instance, that "large amounts of dust" from the Earth's surface thereby enter the Earth's atmosphere. Isn't anything in the air technically in the atmosphere? The point is that it's Earth dust, not the cosmic dust the Climatologists expect.

[noah]

Great points! I went back and edited my original explanation to include some of your ideas. Thanks.

I especially enjoy your point about (D) mentioning earth dust instead of cosmic dust, though perhaps earth dust becomes cosmic dust once it starts to hover over the ground!

[interestedintacos]

That's exactly the "benefit of the doubt" I gave that answer choice while taking this test--that was my problem. I think we are persuaded into thinking that especially by the reference to "cosmic rock."

But judging from the methods of the test makers in the past I think they wanted us to make that distinction. Otherwise this could be a more complicated/interesting case where the correct answer could even be seen as matching a premise in the stimulus, while nevertheless not being a "strengthener" because it didn't add anything we weren't already told. Have you seen that before? Would repeating a stated premise count as a strengthener?

With that said I think the difference comes out from reading that "Earth passes through clouds of cosmic dust that enter the atmosphere." That means the dust at that point is cosmic dust and not in the Earth's atmosphere--the dust enters the atmosphere as a cosmic dust cloud. To make D match with this we'd have to insert the extra piece that the dust that comes from Earth's surface then leaves Earth's atmosphere and becomes cosmic dust clouds that then enter the Earth's atmosphere during fluctuations in Earth's orbit around the sun. What justification do we have for saying the dust would ever leave Earth's atmosphere? Thus I don't think D could be considered as matching or restating a premise even.

To make the point simpler: dust already in the Earth's atmosphere can't count as cosmic dust that starts out in the cosmos and then enters Earth's atmosphere.

[noah]

Right, it may not actually weaken, but it's definitely not strengthening.

As for whether restating a premise can strengthen, no. We're almost always asked to strengthen the argument, meaning the connection between the premise(s) and conclusion, i.e. validate an assumption.

[interestedintacos]

Have you seen a case before where an incorrect answer in a strengthen question was a choice that merely restated a premise? I don't think I can remember seeing that really. Usually they are either weakeners or just irrelevant to the argument.

You mention that "we're almost always" asked to strengthen the connection between the premises and conclusion. Yeah, the cases that don't fit into that in my mind would be the questions where we merely get a claim (no argument) and are asked to distinguish between the 4 choices that would work as premises for the claim and the one choice that wouldn't.

I can imagine some interesting potential cases for strengtheners. For instance, there have been a few stimuli that contained a conflict between premises. One time the arguer accepted two premises, noted that they conflicted and then arbitrarily chose one over the other (it was a flaw question I think). In that case a valid strengthener could be a sort of restatement of the premise the arguer chose--it could be confirming the truth of that premise. This would of course perfectly be in line with everything you're saying about strengtheners--the arguer would be making an assumption that one premise is correct over another, and the strengthener answer choice would back up that assumption.

[noah]

Restating a premise would not qualify as strengthening the argument, and the form of this that you'll usually see is something that explains the premise, but doesn't connect it to the conclusion.

In this question, we're asked to eliminate any any answers that support the hypothesis, which invites answers that provide more evidence. This is a bit more open than "here's a premise, from this we conclude X" and you're asked to strengthen that connection.

As for that strange question, it looks like you figured out how the strengthener is an assumption. I'll have to think about whether there's a typical form of the rare strengthener question for which the answer is another premise. You might be right there.

BTW, for anyone else reading this, while I love to geek out about strange things the LSAT throws at us, I want to emphasize that the key is to focus mostly on the major tendencies of the LSAT, not the infrequent twists.

[interestedintacos]

I did a little more analysis. These pop up everywhere--WeakenX, StrengthenX, etc.X

A strengthener can be the following:

a. additional premise that supports the conclusion/hypothesis from a different angle (while nevertheless consistent with the angle taken in the stimulus)

b. information validating/strengthening a premise (not a restatement of a premise, but certainly info that shows a premise is valid)--for instance, if the argument includes survey data, a strengthener could show that the survey was based on an accurate representation.

c. info that strengthens the connection between a premise and the conclusion

It can be very tricky--one can easily mess up and choose a choice that would, for instance, strengthen the connection between another answer choice and the conclusion of the argument, in which case it would be incorrect. I've been caught by this trick a couple times.

An example to illustrate :

Scientists hypothesize that the decline in the native salmon population of Alaska is due to an increase in ethanoliantacob-VD4, a synthetic chemical byproduct of processing plants located north of the continental US. They base their hypothesis on data collected by the US government that show higher concentrations of chemicals in native salmon habitats throughout Alaska.

All of the following strengthen the scientists' claim EXCEPT:

(A) Ethanoltaco-AC4, similar in composition to ethanoliantacob-VD4, is known to be toxic to fish

(B) The agency that collected the data on chemical concentrations utilized standard procedures that have produced accurate results in the past

(C) The data collected by the US government shows that Ethanoltaco-AC4 is not one of the chemicals found in higher concentrations throughout Alaskan waters
(D) Some processing plants that produce ethanoliantacob-VD4 are located adjacent to native salmon habitats in Alaska

(E) Samples of tissue from dead native salmon in Alaska reveal high concentrations of ethanoliantacob-VD4

[kdeclark]

I'm going to change the subject a bit--going back to something Noah said in his original explanation. He said:

The conclusion of this argument is that the cause of ice ages is the earth passing through cosmic dust clouds, which in turn is caused by fluctuations in the Earth's orbit around the sun. (I always thought that!). The climatologists base their argument on the fact that the occurrences of ice ages, starting 800,000 years ago has coincided with fluctuations in the Earth's orbit around the sun. The climatologists note that the clouds would have to be quite dense for this all to be true.

I see why A would be a strengthener if the argument said what you say. But what it actually says is "...the Earth has undergone a regular sequence of ice ages beginning around 800,000 years ago." I keep reading it out loud and "beginning around" seems to be picking out the "regular series," not the ice ages.

Ex: Baseball leagues have undergone a regular sequence of draft trades beginning around 1900.

That doesn't mean there weren't draft trades before that--just that they weren't regularized.

But if this is the right reading (and maybe you reject my reading), then A wouldn't seem to lend support to the climatologists' hypothesis. No?

[noah]

That's an awesomely close read, kdeclark!

I agree - the argument does not suggest that there were no ice ages before 800,000 years.

But it also doesn't preclude it! Even with the idea that the argument is about a regular sequence beginning, isn't it still possible that there were no ice ages before that sequence began? The stimulus never tells us which way to interpret it. So, let's look at (A) through both lenses:

With the reading that assumes there were no ice ages before, if the supposed reason for the beginning of the series never occurred previously--during that period when there were no ice ages--it would support the idea that this supposed reason is the actual reason.

If we switch to the reading you're suggesting then the clouds are the supposed reason for the series starting--and there's a chance there were irregularly-timed ice ages before then--how does (A) fit in? Well, I think it's the same situation: the cycles started because, it's hypothesized, of these clouds, and as support we see that we didn't have any of these cycles beforehand.

What do you think?

[eunjung.shin]

Does dust from volcanic eruption count as cosmic dust?

I understand why D is right but why is C wrong?

[austindyoung]

Does dust from volcanic eruption count as cosmic dust?

I understand why D is right but why is C wrong?

I had the exact same question. I chose (A) for this one--same reason as another poster did. I now see why (D) is the correct answer.


My main issue with (D) is that it states "cosmic dust," not simply "dust" entering the atmosphere. It seems we would have to list volcano spew as cosmic dust.
So, ya, per the discussion above- the reason to eliminate (C) [because it mentions Earth, not cosmic dust] seems to be an equally valid reason to eliminate (D)-- which we can't.

But...

This may be a stretch- however, since cloud density was an issue here, the volcano dust could actually contribute to the density of the already preexisting cosmic dust clouds.

EDIT: had my (C) and (D) variables mixed up

[Djjustin818]

Could you please explain why E is not the answer? I chose E because I thought it neither strengthened nor weakened the conclusion. It doesn't talk about dense dust clouds, only "rare trace elements known to be prevalent in cosmic debris"

[ManhattanPrepLSAT1]

Answer choice (E) strengthens the argument by strengthening the correlation between the cosmic dust clouds and the ice ages. The rare trace elements (probably talking about something called iridium, which is a common tracer of asteroids and cosmic debris) found in the cosmic debris are found in layers of sediment that correlate with the Earth's ice ages.

While answer choice (E) doesn't say cosmic dust, it does say cosmic debris. In all likelihood, that cosmic dust is cosmic debris (i.e., stuff).
On a Strengthen question, that's good enough to make the conclusion a bit more likely to be true.

[pkraft1]

Just to comment on the debate between C and D, C says there is a causal relationship between dust and cold, which is an assumption of the stimulus. It is part of the hypothesis that "cosmic dust thereby dims the sun, resulting in an ice age," meaning it is not a premise for the hypothesis. C strengthens this causal gap in the argument.

D does not have this causal element to strengthen the argument like C does. There's also the term mismatch of cosmic dust versus earth dust caused by cosmic rock.

[asafezrati]

C also presents an alternative cause. Why doesn't it weaken? Is it because the effect (temperature drop) is weak?

Another question - Does D weaken?