Q26 - All oceangoing ships...

[ohthatpatrick]

Question Type:
Necessary Assumption

Stimulus Breakdown:
Conclusion: A viable way to address problem is to empty and refill tanks in midocean.
Evidence: Emptying and refilling tanks at the docks leads to the ecologically dangerous practice of sucking up sea animals from one habitat and depositing them in a different one. The midocean sea creatures that would get sucked up with this new plan usually can't survive in the coastal habitat.

Answer Anticipation:
The author is definitely assuming that the midocean creatures that get sucked up would usually not cause ecological havoc when dumped (just because they "usually wouldn't survive" in the coastal habitat doesn't mean they couldn't cause ecological havoc before dying). Also, maybe sucking up midocean creatures (which we haven't been doing before) would cause ecological havoc in the midocean ecosystem. Mostly, though, because this author's conclusion is a plan/recommendation, I'd be looking for some other factor that would cause his plan to NOT be a viable solution.

Correct Answer:
E

Answer Choice Analysis:
(A) Extreme: "ensure".

(B) Extreme: "only in".

(C) Extreme: "rarely" / "unless". This is still the most tempting trap answer. But it's talking about the frequency of sea creatures messing up a new habitat. Do we need to know that MOST of the time that a sea creature has wrecked a new habitat, it has / hasn't been because they were deposited in a new habitat by a ship and able to survive there? The "rarely" makes it softer than saying "the only", but saying "the only" makes it easier to understand why this harsh, limiting idea is unnecessary. Does the author need to think that "the ONLY time sea creatures mess up a new habitat is when they've been dumped there by an oceangoing ship?" Of course not. The author doesn't really need to assume anything about what HAS been the case. She needs to assume stuff about what WOULD be in the case IF we started dumping midocean sea creatures in coastal habitats.

(D) Extreme: "only when". Who cares whether it happens at other times as well? When it happens at the dock, we get the problem the author is trying to fix.

(E) Yes! Safe language: "at least some". If we negate this, it says that "There are NO oceangoing ships who could stay adequately stable while attempting this maneuver the author is proposing". That's a death blow to the argument.

Takeaway/Pattern: Knowing that strong language is a red flag and weak language is more useful on Necessary Assumption questions would surely help funnel us more quickly towards E. And using the Negation Test makes it easy to see why (E) would blow up the conclusion.

#officialexplanation

[aharonw1]

I don't understand why C isn't a viable answer.

I took C to be negating a possible problem, of, "Maybe sea creatures can wreak havoc even if they don't survive being offloaded! Maybe their corpses could add pollutants to that area of the sea?"

I saw that E was a necessary assumption as well, but wanted to know why C wasn't considered necessary for the conclusion?

[renata.gomez]

HI,

I'm having a similar dilemma. I see why E is necessary, because if they weren't able to be loaded in mid-ocean then the "viable solution" wouldn't be viable.

The problem with C, I believe, is that it is a little too strong. If this was asking for a sufficient assumption then this would be answer. But it's not "necessary".

Can someone explain why D would be wrong? Would it be because even if it was being emptied and refilled at other times, besides when unloading and loading cargo, they could till comply with the solution given in the conclusion ? For whatever reason, they would have to refill the tank in midocean.

Thank you!

[karishma913]

I'm having a similar dilemma with answer choice C. I get why E makes sense, but not why C doesn't as well.

If C is logically saying: If sea creatures don't survive -> then there's no ecological damage done.
Its negation would be: Sea creatures don't survive but there is still ecological damage done. I'm confused how this answer choice doesn't fail the negation test

[Didius Falco]

This one was very close for me, and I am no Manhattan Expert, so I can only offer the reasoning that got me to E over C on the Test. I hope it is helpful, and that an expert might chime in with their opinion soon.

I was initially tied between E and C, but suspicious about C because of its historical claims. Sea animals "have rarely, if ever, wrecked ecological havoc in a new habitat, unless they have been able to survive in that habitat after having been deposited there by oceangoing ships" just seemed fishy (no pun intended) for a necessary assumption. Then I began to consider some historical possibilities.

What if this assumption is not true. How?

For instance, what if, at some point in the past long before the creation of large ocean-going vessels, fishermen in small wooden boats without ballasts traveled between costal waters and other ecologically fragile costal areas? I imagined it was possible a delicate fish might latch onto the boat at some point, and be carried to another costal region. Upon arrival, the fish might have reproduced in its new habitat and devastated the natural ecology. Maybe this was a pervasive event in ancient times?

So what Falco?

Well, what if that fish is capable of hitchhiking on wooden costal boats, but far to fragile to survive in oceangoing ships? In that case, we have a clear scenario in which a "sea creature" did indeed regularly cause "ecological havoc" in new environments despite his never having been "deposited there by oceangoing ships".

Now, as this is a necessary assumption question, we need to consider if this scenario being true destroys the argument. Would the fact that our fragile-costal-fish has done damage in this manner throughout history undermine the idea that we can address the problem of fish-invaders hitchhiking in ocean ballast tanks by dumping the tanks in the ocean?

I don't think so. Whether or not costal-hitchhiking has happened in history is essentially irrelevant to whether or not our solution to the ballast tank problem will work.

So, in other words, we do not need to assume that there has -rarely been ecological damage from fish except by fish surviving in an environment after being deposited there by oceangoing ships- in order for our argument to work. This is not a necessary assumption.

[renata.gomez]

Hi, I posted a thought process back in August and would really appreciate feedback from MLSAT expert.

Thank you!

[zhuozhuo.li.law]

Hello everyone!

I had a similar situation when I did the question 26 today, but I found that the saying in the stimulus that "one viable way of addressing this problem" did not required that this way must eliminate the problem or must solve most parts of this problem in the stimulus. So C is too extreme because it says "rare". We could accept the scenario that this method just reduces or decreases the extent of this pollution. Therefore C is not necessary by the negation test. So I chose E instead of C.

I am not an language expert and I hope some one can offer a better explanation!

[LukeM22]

So, like the above posters, I was stuck between C and E, and i'm still at a 50-50 split for the following reasons:

1) The same logic that the above posters are using to eliminate C could be used to eliminate E. People are ruling out C because the fact that there is no precedent for something doesn't preclude its eventual possibility (i.e. just because sea creatures haven't historically been able to wreck havoc in unfamiliar environments doesn't mean that they can do so in the future). Fair enough. And just because there are no boats at present that can maintain stability while refilling tanks does not preclude their existence in the future (which could include the time this proposal is actually implemented-- the near future).

2) It is not stated anywhere that perfect stability is actually necessary. It is also unstated whether stability is necessary for the operation underlined. The negation of E could mean that boats simply rock more; the negation of C severely weakens the strength of the argument, because we now have significantly less reason to believe that the purpose of this endeavor-- to wreck less ecological havoc-- would be achieved. It renders the only premise that we have to gauge the worthiness of the endeavor near-irrelevant. Given that the overall goal of this is to reduce the havoc and not to increase stability, I just don't see why the stability should be given higher priority.

Now, if E was the equivalent of "there are boats that can do this", then it would be a clear no-brainer. But I do not feel the stability-feasibility link was ever discussed, much less established.

[ohthatpatrick]

(C) is saying, "Historically, the MOST COMMON way that sea creatures have wreaked ecological havoc in a new habitat was when they were deposited there by oceangoing ships and then survived."

Why would this author need to assume that "being deposited by oceangoing ships" is the most common way that sea creatures have wreaked havoc on a new habitat?

If we negate this and say that "it's very common for sea creatures to have messed up a new habitat, even though they weren't transported there by an oceangoing ship", would that hurt the argument at all?

Of course not. The author isn't saying that this ballast-leads-to-havoc problem is the most common way that sea creatures have wreaked havoc in new habitats. He's just saying it's ONE way in which that can happen, and he thinks he has a viable solution for fixing it.

People who are liking (C) are wanting it to be saying:
Sea creatures have rarely, if ever, wreaked ecological havoc in a new habitat after having been deposited there by oceangoing ships, unless they have been able to survive in the new habitat.

That's saying, "If they don't survive, they rarely, if ever wreak havoc in the new habitat". Sure, that works.

This says, "If they didn't get dumped there by oceangoing ships and live to tell the tale, then they rarely, if ever wreak havoc in a new habitat". That doesn't work, because it now involves all other possible ways that a sea creature would get transported to a new habitat and wreak havoc.

In terms of your problem with (E), if we say "NO ships could ADEQUATELY maintain stability while attempting this move", you don't think that weakens the idea that "This move is a viable solution"?

The whole reason we have this ballast routine in the first place is "to maintain PROPER stability".
By saying "to maintain proper stability, water MUST BE pumped in/out of these ballast tanks" and saying "all oceangoing ships carry these ballast tanks", it sure sounds like we care about proper stability.

If stability weren't a concern, we wouldn't even have these ballast tanks. If they were causing a problem with ecological havoc, we'd just get rid of them, if stability weren't a big enough concern to merit us keeping them.

I think it's fairly strongly conveyed that we're aiming for maintaining proper stability on an oceangoing ship.

[JinZ551]

I want to give my two cents here.

The reason I eliminated C here is based on the term "new habitat".

I noticed that one of the difference (or "term shift"?) between the language in stimulus and answer choice C, is the phrase "new habitat".

While in the stimulus it is indicated that midocean sea creatures cannot survive in coastal area, and coastal sea creature cannot survive in midocean area, what answer choice C gives us is sea creatures cannot survive in "new habitat" unless XYZ... whether or not coastal creatures from coastal area A to survive in new habitat in coastal area B seems irrelevant to the stimulus argument.

The range defined by "new habitat" is way broader than what we need, which is shifts between midocean and coastal area, right?

thoughts?