Q15 - Twenty years ago the Republic

[zl7391e]

I'm not sure whether B is necessary, for the negation of B will not necessarily destroy the argument. I will state my reasons as follow.

Suppose B is false that strains of potatoes most commonly grown in Rosinia could have produced 100m last year (= the yields last year that they once did).

We know in fact the potatoes strains only produced 60m last year instead of 100m, a yield that should have been produced, possibly due to some disasters. For example, a volcanoes has erupted last year, destroying 40m tons of potatoes. Suppose further that this eruption was predicted by some geologists in Rosinia five years ago and those geologists warned agricultural researchers about a potential famine after the eruption and address the need to produce higher-yielding potato strain to reach a yield of, well, 14m per year so that after the eruption the actual yield would drop to 10m to avoid a famine. Under this scenario, agricultural researchers could still be blamed because in anticipation of a disaster, the researchers failed to develop new higher-yielding p strains compared to the p strain twenty years ago, since "they have been concerned only with their own research" (they don't try to develop a better strain and are satisfied in using the strain developed twenty year ago) and "not with the needs of Rosinia".

Before I continue, I want to say that an assumption is necessary for an argument only if the negation of that assumption is logically inconsistent with the original argument( This is my understanding of a necessary assumption. Please correct me if I'm wrong, since this claim plays an essential role in what I'm arguing). Many would think the volcanoes example I cooked up is way too far-fetched, and I agree. But nothing in the stimulus preclude this possibility. So, the volcanoes example is logically consistent with everything said in the stimulus, which suffice for my purpose to show the argument can logically coexist with NOT-B. Therefore, NOT-B will not necessarily destroy the argument. Thus, B is not a necessary assumption.

The example I gave is not important. If you're not happy with it, there are many alternatives. The essence of it is to show that B is not necessary.

[giladedelman]

Thanks for the thoughtful post!

I'm not sure I quite understand your example. But let me give you my understanding of this issue.

First of all, this is absolutely what you need to know: a necessary assumption is an assumption that you need in order to draw the conclusion from the given premise.

What that means is if you negate a necessary assumption, you can no longer draw the conclusion from the given premise. That doesn't mean the conclusion becomes false; it just means it no longer follows from what we know.

So in the case of this argument, we know two things about the researchers: they didn't develop new higher-yielding strains of potatoes, and they have been concerned only with their own research. From this, the argument concludes that they are to blame for the diminished harvest.

So why is (B) a necessary assumption? Because if there actually were strains that could give us the 100 million ton yield we were looking for, then we have no justification for blaming the researchers. All we know is that they didn't develop new strains, so it's necessary to assume that we actually needed new strains. If the old strains were perfectly fine, then someone or something else must be to blame.

(With respect to your example: answer (B) explicitly says these strains couldn't have produced the yields; if we negate it, we're saying they could have produced the yields, so there's no possibility that the yields would have been diminished by disaster or something -- we're saying the yields would be there.)

(A) is out because we don't need to assume these attempts are futile; in fact, the point is that the researchers should have succeeded.

(C) would actually weaken the argument by suggesting that focusing on their own research could actually help the researchers solve the problem.

(D) is incorrect because the point is not whether the change is uncommon, it's whether the researchers are to blame.

(E) is totally out of scope; we don't care about the funding.

Does that clear up this issue for you?

[hoyeon.cho]

thanks for your explanation
but, how about this case?
let say there are three potato strains A,B,C

20 years ago: A=50M, B=25M, C=25M
last year: A=50M, B=5M, C=5M

in this case, the most commonly grown one is A
but it did produce the yield that they once did

is that my misunderstanding?

[WaltGrace1983]

So why is (B) a necessary assumption? Because if there actually were strains that could give us the 100 million ton yield we were looking for, then we have no justification for blaming the researchers. All we know is that they didn't develop new strains, so it's necessary to assume that we actually needed new strains. If the old strains were perfectly fine, then someone or something else must be to blame.

(With respect to your example: answer (B) explicitly says these strains couldn't have produced the yields; if we negate it, we're saying they could have produced the yields, so there's no possibility that the yields would have been diminished by disaster or something -- we're saying the yields would be there.)

(D) is incorrect because the point is not whether the change is uncommon, it's whether the researchers are to blame.

So (B) is a necessary assumption because if we say that "strains of potatoes most commonly grown in Rosinia COULD have produced the yields last year that they once did" then the scientists needed not to find new strains in the first place. The whole argument is saying "well, the agricultural researchers should have been developing new strains of potatoes and therefore they are to blame!" but (B) is saying "well hold on! the strains were fine! It wasn't the researchers fault because those strains had the full capability of producing what they needed to produce and therefore it was some outside source that really caused the famine" because, after all, if these strains COULD HAVE produced what they needed to and DIDN'T then there must be a reason."

Ok I think I got that.

I originally picked D because it had the language of what I was looking for. My initial thoughts were ok so maybe there was no reason for everyone to get so worked up about a 40 million potato deficit because it happens all the time!. If it was usual then maybe it wasn't anyone's fault and it is just "how things go" so to speak. However, I also see that not only is D wrong but it is the OPPOSITE of what we are looking for here.

"Wide fluctuations in the size of the potato crop over a 20 year period ARE unusual." We don't necessarily have to assume the negation (to thereby strengthen the argument) but the negation certainly strengthens the argument. It does this because it says that this is common and if it is common perhaps it is not anyone's fault. Sometimes crops just don't work out the way you want them to.

[lsatzen]

Hi MLSAT Staff,

I just wanted to re-hash the discussion that went on about why answer choice B was in fact necessary, in MLSAT concepts and terminology. So if I am mis-applying anything please feel free to correct me!

This is a necessary assumption question so we know that the correct answer choice will usually either 1) support the argument by providing a missing link between premise and conclusion or 2) defend the argument by denying alternative possibilities. Keeping these in mind, after jumping into the stimulus we find out that:

1) Agri researchers didn't develop new higher-yielding strains of potatoes, 2) they have only been concerned with their own research. From this they conclude that the Agri researchers are to blame for the deficiency of last years harvest.

By noting that the author of the argument is concluding that the researchers, and the researchers alone, are to blame for this deficiency in the potato harvest, would it be safe to assume at this point that the correct answer choice will exploit this typical case of LSAT arrogance (arrogance here meaning that the author of the argument is confident that there is indeed only one cause / person to blame) by assisting the author by denying alternative possibilities for him?

That meta-issue aside, we also know that B is a necessary assumption because it denies an alternative possibility that would destroy the argument. The negation of B gives us the statement "strains of potatoes most commonly grown in Rosinia COULD have produced the yields last year they once did". If it is true that the crops COULD have produced the results (100millon tons), it would lessen our justification (or in other words, destroy the link between premise and conclusion) in asserting that the researchers are to blame. Because then the scientists would not NEED to be held responsible for finding new higher-yielding strains to begin with; namely, because it seems that the argument is assuming that harvest yields that are deficient, require additional help in order to achieve its non-deficient yield of 100 million tons (i.e. the involvement of the Agricultural researchers).

If we deny this possibility of the fully capable strains, then we are essentially saying that the plants could NOT have produced the the same yields as last year and therefore need additional help from the researchers in the form of the development of new higher-yielding strains.

I really hope this makes sense. I would also love some feedback on how to condense my approach and make it more efficient / less convoluted.

[maryadkins]

It does make sense. But you can stop as soon as you know that negating (B) destroys the argument. You don't need to get into this, in other words:

If we deny this possibility of the fully capable strains, then we are essentially saying that the plants could NOT have produced the the same yields as last year and therefore need additional help from the researchers in the form of the development of new higher-yielding strains.

Negate and if doing so destroys the argument just as you said, be done with it!

But no, I don't think there's a faster approach apart from stopping where you can fee free to stop. You are thinking correctly.

[seychelles1718]

I was thrown off by "strains of potatoes most commonly grown" in B. I thought we don't need to assume anything about "most commonly grown" strains of potatoes because the total potatoe yield could still DECREASE even if the most commonly grown strains of potatoes COULD have produced yields last year that they once did, if OTHER, LESS commonly grown strains of potatoes FAIL to produce as much as they once did.
so I thought the author does NOT need to make such specific assumption.

Can anyone please correct my reasoning?

Another thing is, if A is changed to "any attempts by agricultural researchers so far to develop higher-yielding potato strains are futile," could this be the correct answer? because we can no longer draw the conclusion from the premise that those researchers have been concerned only with their own research and not with the needs of Rosina.

Thanks!!!

[maryadkins]

If the most common strains could have produced much more than they did, I don't see how the researchers are the ones to blame for not coming up with a better strain. That means that the strains weren't the problem.

As for your rewrite of (A), I still don't see how that would be necessary. We're told the researchers failed to produce higher-yielding strains; that's a given. The conclusion of the argument is that they should have done it, and that the new strains would have been better for Rosinia. If it would be pointless for them for them to do it, as (A) says, how would this be in line with the argument? (A), if anything, is saying the opposite of what we would want.

[LolaC289]

I found it makes this question so much easier if we see the conclusion as two parts.

The conclusion actually claims two things: first, the agricultural researchers are blameworthy. Second, they are blameworthy because they failed to develop new potatoes.

The correct answer thus can be address both ends: from the premise to the first/second claim of the conclusion.

As to the first gap: Just because the harvest went from 100m tons to 60m tons, does that mean the researchers are blameworthy? The answer is no. In fact, it is highly possible that this reduction is perfectly normal and Nature is the one to blame (and not the researchers).

Answer choice (D) wants to address it. But it's a shame that it has it wrong. If we are to make this answer choice right, we should assume the wide fluctuation of the potato harvest are unusual, instead of "not unusual ". Because if the wide fluctuation is not unusual, i.e. usual, then negate it, we get: wide fluctuation is unusual, the author's argument would thus be strengthened, not destroyed! Have you figure it out? And the LSAT writers love to get it backwards so we will be trapped by it.

(B) addressed the second gap. Negate (B) we get: the old potatoes could produce 100m tons of last year(it's just out of some weird condition that they didn't achieve that), then the old potatoes are perfectly fine and we can't blame these researchers for not developing new ones.

Hope this helps. (from someone who tripped on (D) for two times)

[obobob]

I found it makes this question so much easier if we see the conclusion as two parts.

The conclusion actually claims two things: first, the agricultural researchers are blameworthy. Second, they are blameworthy because they failed to develop new potatoes.

Hi Lola, isn't the argument arguing that the agricultural researchers are blameworthy for the reason that they have been concerned only with their own research? I was thinking the part that says the researchers have failed to develop new higher-yielding strains of potatoes as another background information or premise instead of the reason for the conclusion.

I think I can get to the correct answer with either way of interpretation, but I decided to ask since I got to the point where I started to get confused with distinguishing with some premises, backround info (context), and conclusions in certain stimulus. So I thought I'd better ask.

Thanks!

[ohthatpatrick]

Modifying clauses in a conclusion are not part of the truth value that's up for grabs.

For example:
Those apples are too high up for Alex to reach. Thus, Megan, who is very athletic, can reach them.

We wouldn't be debating whether Megan is very athletic. That modifying clause is providing us with more information on the subject noun of the conclusion.

Similarly, on Q15 the conclusion is:
CONC: Agricult. researchers are to blame for the 100 -> 60 decrease over the past twenty years.

EVIDENCE:
they haven't developed new higher-yielding strains of potatoes
they have been concerned only with their own research and not with Rosinia's needs.

[EmilyL849]

Hi, all

I have one question regarding (B).

I understand that by blaming the decrease of potato yield on failing to develop new higher-yielding strains, the author is assuming old stains, collectively, could not have produced 100 mil.
However, (B) it says strains of potatoes most commonly grown could not have produced the yields last year that they once did. The thing is we are not told how much most commonly grown strains used to produce. They could have produced 30 mils twenty years ago. (Yes, they could have produced 100 mil, but we just cannot assume the amount. "Most commonly grown" could range from 1% to 99% of output for all we know. )

Without that information, even if existing most commonly grown COULD have produced last year that they once did, it is still possible that total output waned to 60 mil. Maybe the other strains are not performing really badly and researchers should have developed a new higher-yielding strain.

I wonder what could be going wrong in my reasoning

THank ou!

[JianqiaoH853]

I got the answer right, but still, have a question about (A).
If we negate (A), then it follows that "there is at least one attempt to develop higher-yielding potato is not futile", which means researchers have already successfully achieved that, then the researchers actually shouldn't be blamed.