Q12 - Though Earth's human population is

[smiller]

Question Type:
Weaken

Stimulus Breakdown:
Premise:
Humans only use a relatively small fraction of fresh water supply.

Conclusion:
Water shortages will not plague mankind even if the human population continues to grow.

Answer Anticipation:
There are a few significant flaws in this argument:
1. The argument doesn't address how fast the population is growing. We might only be using a small amount of available water now, but the population could be increasing fast enough that our needs will exceed the supply some time in the near future.
2. The supply could be decreasing.
3. Even if a large supply exists, we might not be able to access all of it for some reason.

A correct answer could indicate that one of these situations does in fact exist.

Correct Answer:
(B)

Answer Choice Analysis:
(A) This doesn't have to weaken. It might seem to at first glance: if growth trends are hard to predict, perhaps the population will grow much faster than expected. However, if growth is hard to predict, it's just as likely that the population will not grow as fast as expected, which wouldn't weaken the argument.

(B) This is the correct answer. The premise tells us that the human population as a whole currently uses only a small fraction of the fresh water supply. It doesn't tell us that fresh water is readily available in every place where humans live. There could be severe water shortages in many places, even if as a whole humans continue to only use a small fraction of the fresh water supply. This isn't exactly like the third flaw we predicted above, but it's very similar: even if there is a large supply, everyone might not have access to it.

Choice (B) might seem to be worded rather mildly, making us question how much it weakens. It's important to note that the conclusion of the argument is quite strong and absolute: the claims about water shortages are mistaken! We won't be plagued by shortages! An answer doesn't have to create a huge amount of doubt to weaken such a strong conclusion. If the amount of water available varies "significantly," that creates enough doubt.

Some people might dislike choice (B) because the argument's conclusion is about shortages that "plague humankind," while choice (B) only implies that some regions will experience water shortages while others won't. However, an issue can "plague humankind" without directly affecting every person. If half of the houses on my street were burglarized last week, people might say that my neighborhood is plagued with crime; it might be accurate for them to say this even if my house wasn't robbed, and I don't feel affected in any way by my neighbors' misfortune.

(C) This is too weak of an answer. Nothing in the stimulus indicates that water conservation methods are needed. The premise states that we're only using a small fraction of the available fresh water. Why do we need to conserve? Also, (C) only tells us that some people won't adopt conservation methods. It leaves open the possibility that a large portion of the population will do so.

(D) This is out of scope. The conclusion in the stimulus is about the near future. The sun is eventually going to turn into a red giant star and vaporize the Earth, but that doesn't mean life on Earth will be wiped out "in the near future."

(E) This is an irrelevant comparison. If agricultural water use grows more quickly than industrial use, it doesn't mean that water use as a whole will grow fast enough to cause shortages in the near future.

Takeaway/Pattern: Anticipating answer choices is about understanding the stimulus and predicting what a correct answer might look like. You might not predict the exact correct answer, but anticipating will help you recognize one that is similar, and will help in eliminating incorrect answers.

#officialexplanation

[hyewonkim89]

I was down to (B) and (D) and ended up choosing the wrong answer!

I thought at first that if population keeps increasing, it will outstrip all available resources including fresh water. BUT, then I realized that the stimulus states population growth trends change.
Which probably means population will grow anyway. Also, I figured since (D) says "eventually" rather than "in the near future," it wouldn't be the best answer.

As for (B), I'm still a bit confused on why it's the right answer.

Is it because since different regions need different amount of fresh water, it will be a big problem to certain regions? For example, many African nations lack fresh water and a lot of people go through days without any water whereas people in the US can have fresh water everyday. But since there are water shortages in Africa, the US need to help out with its resources therefore slowly outstripping its own fresh water.

Please help!

[GeneW]

I also have a question as to why B is the answer. How does different region play a role?

Would water shortage not be a problem if it only affects a certain region versus the entire human population?

Thank you in advance.

[ohthatpatrick]

PREM:
we currently only use a small fraction of the Earth's supply of fresh water

thus,
CONC:
people are wrong to say that if the population keeps growing, there will be terrible water shortages


When I tackle most Assumption Family questions, I find it helpful to immediately say the "Anti-Conclusion", to wear the hat of someone who disagrees with the conclusion.

Here, the Anti-Conclusion is "There WILL be terrible water shortages".

Me: People are RIGHT to say that if the population keeps growing, there will be terrible water shortages.

Author: Nuh-uh, we currently only use a small fraction of the fresh water supply.

Me: _____ ????

How can I respond to that?

I read the answer choices waiting for an answer that can give me a way to respond.

(A) This doesn't help me respond. I need to give a reason why we will still have water shortages. This is about how accurate you can or can't predict population growth.

(B) This could work.

Author: Nuh-uh, we currently only use a small fraction of the fresh water supply.

Me: That's true, our total consumption is only a small fraction of the global supply. But some regions have disproportionately LARGE water supply and other regions have disproportionately SMALL water supply. Those regions with a very stretched, limited water supply will have trouble meeting water demands if the population continues growing.

(C) This says that some people will NOT adopt water conservation methods. That would only strengthen the idea that there will be water shortages.

(D) This is super close, but "it will eventually outstrip" does not clearly relate to "water shortages in the near future". I mean, (D) is technically just saying a boring mathematical truth: if the population grows infinitely, it will eventually overtake a finite supply.

But, as the author would quickly remind us, we currently only use a small fraction of the finite water supply, so we're not gonna have to worry about water shortages in the near future.

(E) This answer is bringing up a useless distinction between water used for agriculture and water used for industry. Both uses are still just uses of water. They all get lumped together in our big calculation of water use vs. water supply. So who cares about how the water use gets divvied up?

The one weird aspect with (B) is that it helps us to argue that there will be regional water shortages. It's a little frustrating that the claim we're disputing in the conclusion uses the phrase "water shortages will plague humankind".

It seems like the conclusion is focused on a wider, more dramatic problem than the objection we derive from (B).

But 2 things:

1 - answers don't have to be perfect. Weaken answers don't have to prove the author was wrong. They just have to introduce doubt.

2 - 'plague humankind' doesn't mean 'all of humankind has a water shortage'. When I learn of water shortages in other parts of the world, it distresses me. If those became even more dramatic, it could certainly 'plague me', even though I'm not directly involved. It's fair to say that "cancer currently plagues humankind" even though less than half of us currently have cancer.

Hope this helps.

[GeneW]

Thank you for the explanations.

[asmaa737]

I thought (C) was wrong b/c it mentioned that "not all" will adopt water conservation methods. This could mean that 99% of the world's population will adopt water conservation methods, which if anything, strengthens the conclusion that there won't be a water shortage with or without population changes.

Is my reasoning correct?

[sumukh09]

The one weird aspect with (B) is that it helps us to argue that there will be regional water shortages. It's a little frustrating that the claim we're disputing in the conclusion uses the phrase "water shortages will plague humankind"

This is precisely why I chose to overlook B as the correct answer to this question. The stimulus seems to be taking on a "bigger picture" perspective about the relationship between the water supply and the increase in population size. When I read "plague humankind" I was certainly not inclined to think that the correct answer choice would address "regional" issues about the shortage of water supply - rather, I'm immediately looking for an answer choice that conforms to a more absolute or broad perspective; hence why I chose D), and I was fairly confident with it as well. Also, another issue I had with B was that the claims made in the stimulus already accounted for the regional differences; after all, we're talking about the "earth's population" and surely that includes all the regions that encompass the earth.

I'll concede that a minor issue with D is that it doesn't address the temporal aspect that the stimulus introduces ie) addressing problems of water shortages in the near future, however, I thought that the other components of the answer choice far outweighed this minor issue. In particular, the answer choice makes me question the claims in the stimulus about not worrying about a population increase and it creating a problem for the water supply ie) by providing the logical consequence that all resources will be outstripped if the population increases.

I saw the core as:

we currently use a small fraction of the water supply even though the population is increasing ----> we don't need to worry about the increase in population causing problems for the water supply


So I thought I had to look for an answer choice that connected the idea that an increase in population WOULD have detrimental effects on the water supply -- and I thought D hit the nail on the head with this.

Any further clarification would be appreciated! Thanks

[ohthatpatrick]

In regards to (C), my previous comment made a mistake. I mistakenly said that (C) would strengthen, but if anything (C) would slightly weaken.

But I do want to caution people against thinking that when we hear a statement like
"Not all my friends are Democrats"
we can assume that a high % of friends ARE Democrats, but some leftover portion is not.

Even though that’s how we think about that type of statement in the real world, it is not logically true.

For instance, it is a true statement to say that "Not all NFL players are female".

(If you disagree that that is a true statement, then you think that "all NFL players are female")

You can see how the same thinking here would get us into trouble:
"Not all NFL players are female"
does not tell us that a high % of NFL players ARE female, but some leftover portion is not.

Instead, any "˜Not all A are B’ statement simply tells us that "At least some A are ~B".

So whenever you see a "˜Not all’ statement, you should translate it into the "at least some" form.

Hence, all that (C) actually tells us is "at least some of Earth’s population will NOT adopt conservation methods". Learning that some people will NOT conserve water slightly pushes back against the conclusion "water shortages will not plague humankind".

In reality, it doesn’t push back against the author’s reasoning, since he thinks we have an ample supply of fresh water (we’re only using a small fraction of it), thus "˜water conservation’ was never something he was arguing we needed.

On to (B) -
Ultimately, we’re going to pick (B) because nothing else helps at all. So even if (B) only suggests that water shortages will plague "˜regional patches’ of humankind, it still does more than any other answer.

However, I would argue that you can say that something "˜plagues humankind’ without meaning that all humankind is directly affected by it.

If I say "I’m plagued by indecision", it doesn’t mean that every single choice I have to make paralyzes me. Instead, it just means "I am often indecisive and it is a problem." So for water shortages to "˜plague humankind’ they just need to be a frequent problem, not an omnipresent one.

During WWII, we might have called the Nazis "˜a plague on humankind’, even though people in South America were presumably not directly plagued by them.

Similarly, regional water shortages could presumably cause tensions within the international community as those without water strive to get help from those with it (not to mention the wars that might develop as a result). Regions with AMPLE water might still suffer from the plague of water shortages purely by sympathetically mourning the sad state of affairs in regions without enough water.

So we can definitely pick (B) because it does more than anything else, or we can tell ourselves that if many regions of humankind are suffering, then the common cause of that suffering plagues humankind.

[icebreaker]

Hence, all that (C) actually tells us is "at least some of Earth’s population will NOT adopt conservation methods". Learning that some people will NOT conserve water slightly pushes back against the conclusion "water shortages will not plague humankind".

In reality, it doesn’t push back against the author’s reasoning, since he thinks we have an ample supply of fresh water (we’re only using a small fraction of it), thus "˜water conservation’ was never something he was arguing we needed.

Hi Patrick,

I'm still confused about (C). Would you be able to help?

The conclusion, by negating the unless statement is:
Water shortages will NOT plague human kind in the near future EVEN IF population growth trends DOES NOT change.

Like you explained, (C) says that at least some of Earth's population will not adopt water conservation methods in the near future.

If it is the case that some groups of people will NOT conserve water, does this not weaken the conclusion that water shortages will be a problem? It's really vague because we're not sure about the size of the population not conserving water, but I can still see how it weakens slightly.

Please let me know what you think. Thanks!

[judaydaday]

Hence, all that (C) actually tells us is "at least some of Earth’s population will NOT adopt conservation methods". Learning that some people will NOT conserve water slightly pushes back against the conclusion "water shortages will not plague humankind".

In reality, it doesn’t push back against the author’s reasoning, since he thinks we have an ample supply of fresh water (we’re only using a small fraction of it), thus "˜water conservation’ was never something he was arguing we needed.

Hi Patrick,

I'm still confused about (C). Would you be able to help?

The conclusion, by negating the unless statement is:
Water shortages will NOT plague human kind in the near future EVEN IF population growth trends DOES NOT change.

Like you explained, (C) says that at least some of Earth's population will not adopt water conservation methods in the near future.

If it is the case that some groups of people will NOT conserve water, does this not weaken the conclusion that water shortages will be a problem? It's really vague because we're not sure about the size of the population not conserving water, but I can still see how it weakens slightly.

Please let me know what you think. Thanks!

I had a hard time with this question. All the answer choices seemed so irrelevant...

(C) is tricky because it seems to attack the conclusion very well. But I think (C) is incorrect because the premise states that the human population is using only a relatively small fraction of the water supply. So if this IS true, then water conservation is not necessary?

On another note, is (B) pointing out a whole to part flaw? Just given that fact that the ENTIRE human population is currently using only a small fraction of the TOTAL supply of fresh water, you cannot say that this is true about each individual REGION (or part) of the Earth.

[rinagoldfield]

Thanks Judayday. You are EXACTLY right that (B) points out a part-whole issue. Great eye!

(C), if anything, strengthens the argument, since it suggests that some of the Earth’s population will NOT be conserving water. This hurts the idea that there won’t be water shortages!

[aryehkln94]

Hey mlsat!

I do not understand how B weakens, it's very nice that the amount of water varies from region to region but u can say that means that one region has enough water for 500 years and one for 1000 years even if population increase, this answer choice kinda swings both ways!?

Thx!

[contropositive]

Hey mlsat!

I do not understand how B weakens, it's very nice that the amount of water varies from region to region but u can say that means that one region has enough water for 500 years and one for 1000 years even if population increase, this answer choice kinda swings both ways!?

Thx!

Every time I've done this question, I struggled with it but after thinking about it and reading the above posts I think I have a better understanding of it and can help you.

The core is:
right now the Earth is using a small fraction of the water. Therefore, we will not have water shortage in the near future even if the population continues to increase.

Two red flags: 1. fraction (when LSAT tries to do math, I know their going to mess up bad) 2. temporal flaw (what happens now doesn't tell us much about the future)

Even if the Earth is using a small fraction of water right now this fraction may not be enough for people in other regions if that region's population increases. For example, Los Angeles and Arizona may currently be using a small fraction of water and it's enough. But if Arizona's population increases that small fraction is no longer enough whereas it continues to be enough to feed Los Angeles people even if their population increases. Essentially this is what B is telling us...that various regions will be impacted differently.

I was stuck with D but I read somewhere that the problem with D is that "eventually" is too vague and does not equate to "near future"

This is how I understood it. I'm not sure if I am 100% correct. Hopefully someone can give us more clarification.

[pewals13]

contropositive...

I like to think of (D) as stating something that both is irrelevant to the conclusion and information you pretty much already know.

Point 1: What eventually will happen is not really relevant to the conclusion that:

"Water shortages will NOT plague mankind in the near future --> (Requires) A change in population growth trends"

How does answer tell me anything about what avoiding water shortages in the near future will or will not require?

Point 2: You already know that if Earth's population increases continually it will at some point outstrip what are (presumably) finite resources

[ganbayou]

I thought B is wrong because they might be able to get water from other countries if they run out their water...
In real world people help each other a lot and even if they may not get those water for free, they can buy them.
Why we are not allowed to think in this way in this question?

[ohthatpatrick]

You ARE allowed to think that way, but thinking that way won't help you answer the question.

People are annoyed with (B) because it doesn't come close to crushing the conclusion, nor does it even seem like a particularly stinging BURN against the author.

There are a lot of Weaken questions out there like this, in which the correct answer barely weakens, but it does more than everything else.

A Weaken answer just has to create some doubt surrounding an author's assumption or conclusion, or it can diminish the trustworthiness / relevance of the evidence to the conclusion.

You can think about (B) as simply exposing the faulty move from "humans use only a small fraction of total water supply ---to---> humans won't have water shortages in the near future."

(B) hurts the argument by pointing out that judging water supply based on TOTAL supply of fresh water is possibly a bad idea, given that the total supply is distributed in a very lumpy way.

The first regions that run out of water MAY get help from other regions, or the other regions may exploit them with high water prices, leading to water-wars, etc.

As long as we've achieved doubt, we've weakened the argument at least somewhat.

(C) does nothing to weaken because there's no reason (yet) to think we need any water conservation methods. Plus, it's really weak. It literally says "at least one member of Earth's population will not adopt water conservation in the near future".

(D) does nothing to weaken because we're not debating whether there will be water shortages EVENTUALLY. We care about the near future.

So (B) is the stinker of a winner that creates SOME possibility that we'll have water shortages in the near future. Even though the Earth's total supply of fresh water is much more than what we're using, the local/accessible supply might be very close to or below what we're using in those regions.

For another stinker of a correct Weaken answer, try this one:
https://www.manhattanprep.com/lsat/foru ... -t705.html

[ganbayou]

You ARE allowed to think that way, but thinking that way won't help you answer the question.

People are annoyed with (B) because it doesn't come close to crushing the conclusion, nor does it even seem like a particularly stinging BURN against the author.

There are a lot of Weaken questions out there like this, in which the correct answer barely weakens, but it does more than everything else.

A Weaken answer just has to create some doubt surrounding an author's assumption or conclusion, or it can diminish the trustworthiness / relevance of the evidence to the conclusion.

You can think about (B) as simply exposing the faulty move from "humans use only a small fraction of total water supply ---to---> humans won't have water shortages in the near future."

(B) hurts the argument by pointing out that judging water supply based on TOTAL supply of fresh water is possibly a bad idea, given that the total supply is distributed in a very lumpy way.

The first regions that run out of water MAY get help from other regions, or the other regions may exploit them with high water prices, leading to water-wars, etc.

As long as we've achieved doubt, we've weakened the argument at least somewhat.

(C) does nothing to weaken because there's no reason (yet) to think we need any water conservation methods. Plus, it's really weak. It literally says "at least one member of Earth's population will not adopt water conservation in the near future".

(D) does nothing to weaken because we're not debating whether there will be water shortages EVENTUALLY. We care about the near future.

So (B) is the stinker of a winner that creates SOME possibility that we'll have water shortages in the near future. Even though the Earth's total supply of fresh water is much more than what we're using, the local/accessible supply might be very close to or below what we're using in those regions.

For another stinker of a correct Weaken answer, try this one:
https://www.manhattanprep.com/lsat/foru ... -t705.html

Thank you for ur reply!
May I ask a question?
I was not sure between C and B and for C as you says "(yet)" but it also MAY happen right?
That's why I was not sure because I thought both of them create doubt.
I understand "not all" is weak, but at least it means "at least one" does that. B is more vague, what you said may happen but may not!
...so I chose C.
Could you elaborate the explanation a bit? I had such a hard time to eliminate C

[rachel.miklaszewski]

PREM:

(E) This answer is bringing up a useless distinction between water used for agriculture and water used for industry. Both uses are still just uses of water. They all get lumped together in our big calculation of water use vs. water supply. So who cares about how the water use gets divvied up?

The one weird aspect with (B) is that it helps us to argue that there will be regional water shortages. It's a little frustrating that the claim we're disputing in the conclusion uses the phrase "water shortages will plague humankind".

It seems like the conclusion is focused on a wider, more dramatic problem than the objection we derive from (B).

Hi Patrick - appreciate your feedback on this question. But I think that Answer E does the exact same thing as B, which is why I was struggling with this answer. Answer choice B discusses regional differences in water - helping us make the case that maybe if some regions are using large amounts of water, water shortages could plague humankind.

But E does that in a better way because it assures us that agriculture will be increasing more quickly than industry - not only is water use different between agricultural and industrial regions, but agriculture is increasing more quickly - leading to a water shortage that will plague humankind.

Why isn't this reasoning correct?