PT 70, Sec 4, Q 12 Forum

[azizbaba]

I'm a little confused why answer choice (B) is the correct answer. It assumes without providing justification that in the near future humankind will not be able to transfer water supply easily from one part of the planet to the other.

Answer choice (E), in my view, is a better answer choice. Agricultural water demand may grow exponentially with respect to the population size.

[Yazzzay]

bump

i put D actually, and read lsat hacks, still don't get it

[Christine (MLSAT)]

I'm a little confused why answer choice (B) is the correct answer. It assumes without providing justification that in the near future humankind will not be able to transfer water supply easily from one part of the planet to the other.

Answer choice (E), in my view, is a better answer choice. Agricultural water demand may grow exponentially with respect to the population size.

But (E) doesn't say that agriculture water demand may grow faster than population does. It says that agricultural water demand may grow faster than industrial water demand does. There's no connection to population at all.

Also, you should strip your process of the idea that if a weakener assumes something, or only applies in certain cases, that it's no longer a valid weakener. Weakeners do not have to disprove the argument, they merely have to damage the connection between premise and conclusion, and by doing so make the conclusion somewhat less likely. If the amount of water available varies widely from region to region, then maybe some regions will not have enough water for their needs, even though we have plenty of water worldwide. It's not a guarantee, but a weakener doesn't have to be.

The relationship between agricultural water demand and industrial water demand doesn't make the water shortages more (or less) likely. It's just not relevant.

As for (D), the fact that population will eventually outstrip the water supply doesn't make it more likely we'll have water shortages in the near future, which is what the conclusion is about specifically.

[nooooo]

I took the conclusion and turned it into a conditional:

If no population growth trend changes (then) water shortages will plague humankind
(Author says this claim is "mistaken")

Words that lead I held onto; "currently", "near future", "small fraction"
----------------
----------------
(A) - Trends could still "not change" and fully agree with author's contentions

(B) - By positing that "humankind" will not be plagued, it leaves the argument open so weakening any facet of "humankind" being plagued will hurt the argument. Here, it could be that a tiny village in Africa is out of water because of recent prayers to their fertility god is getting everybody to pop out babies and now, water is scarce.

(C) - Trends could still "not change" and fully agree with author's contentions

(D) - Compare this answer to the conditional and it's basically a mistaken reversal (at least that's how I took it). And it mentioned "currently" and "near future", so I found the scope too broad in this particular instance; it was this that lead me to pick (B) over (D).

(E) - This answer is comparing percentage of water used between agriculture and industry. Doesn't talk about it in comparison to humankind.

[azizbaba]

But (E) doesn't say that agriculture water demand may grow faster than population does. It says that agricultural water demand may grow faster than industrial water demand does. There's no connection to population at

.

(E) suggests that the water demand curve is not necessarily a linear function.
If for answer choice (B) we are going that far to presume that humankind will not be able to transfer water from one region to another, why shouldn't we presume for answer (E) that the growth of both industrial and agricultural water demands depend on the population growth but one grows faster?

[Christine (MLSAT)]

But (E) doesn't say that agriculture water demand may grow faster than population does. It says that agricultural water demand may grow faster than industrial water demand does. There's no connection to population at

.

(E) suggests that the water demand curve is not necessarily a linear function.
If for answer choice (B) we are going that far to presume that humankind will not be able to transfer water from one region to another, why shouldn't we presume for answer (E) that the growth of both industrial and agricultural water demands depend on the population growth but one grows faster?

The water demand curve is not a linear function of what? If we're going to get into a math view of this, then you're going to have to think about which is the independent and which is the dependent variable of the non-linear function you're talking about. Neither of those variables is population. If you're a math person, and this make sense to you, awesome - but if you're not, then this way of looking at it is just going to make it more confusing.

The mistake you're making is a pretty classic one when it comes to weakeners/strengtheners. Weakeners do not have to successfully kill the argument every time, but they do have to make it less likely to be successful.

Let's say you have a lottery ticket with a 10 digit number. You say that you're going to win. A valid strengthener would be: "the lottery ticket's first digit is a 7, and the winning number's first digit is a 7." That makes it more likely that the lottery ticket will win. It does not guarantee it. To guarantee it you have to make a bunch of assumptions about the remaining numbers.

This is just like (B). If the amount of water available varies widely from region to region, it's a little less likely we'll avoid water shortages. Water shortages aren't guaranteed - we need a host of assumptions for that - but they are a bit more likely now.

Back to the lottery ticket. If I say: "the lottery ticket is blue", that doesn't help strengthen the idea that it will win. I could add in a bunch of assumptions about the numbers, and still win - but my assumptions have done ALL the lifting now. The BLUENESS of the lottery ticket doesn't make winning more likely, at all.

This is just like (E). The relationship of agricultural water demand to industrial water demand doesn't affect the argument about water shortages. You can add in a bunch of assumptions about tying both to population growth rates, but then it's that relationship to population growth rates that affects the argument. The information in the answer choice doesn't do a thing, just like the blueness of the lottery ticket.

The weakener must make the conclusion less likely on its own, but it doesn't have to guarantee the conclusion's failure. If assumptions are required to guarantee that failure, that's fine. But if assumptions are required to even make the conclusion a bit less likely, then the answer choice itself isn't doing anything.

Make sense?

[azizbaba]

The water demand curve is not a linear function of what? If we're going to get into a math view of this, then you're going to have to think about which is the independent and which is the dependent variable of the non-linear function you're talking about. Neither of those variables is population.

why do you assume that none of those variables is population?
In order for answer choice (E) to be a correct answer, it needs the assumption that agricultural and industrial water demands are both function of the population size.

All, I'm saying is why (B) is better than (E) when answer choice (B) does not stand on its own and it needs a series of presumption to be a correct answers?

[Christine (MLSAT)]

The water demand curve is not a linear function of what? If we're going to get into a math view of this, then you're going to have to think about which is the independent and which is the dependent variable of the non-linear function you're talking about. Neither of those variables is population.

why do you assume that none of those variables is population?

I'm not *assuming* that. That's what (E) says. (E) tells us that the relationship between agricultural water demand and industrial water demand is non-linear. If you're trying to say that (E) tell us that 'water demand is a non-linear function', then the variables involved are 1) agricultural water demand and 2) industrial water demand. Neither of those is population.

But I still don't think this is a particularly useful way to look at (E).

All, I'm saying is why (B) is better than (E) when answer choice (B) does not stand on its own and it needs a series of presumption to be a correct answers?

(B) does not need any presumptions to make the conclusion less likely. It would only need presumptions to GUARANTEE the conclusion fails.
(E) requires assumptions to make the conclusion even slightly less likely. On its own it does absolutely nothing.

Did you understand how the lottery ticket example related to this?

[bp shinners]

The water demand curve is not a linear function of what? If we're going to get into a math view of this, then you're going to have to think about which is the independent and which is the dependent variable of the non-linear function you're talking about. Neither of those variables is population.

why do you assume that none of those variables is population?
In order for answer choice (E) to be a correct answer, it needs the assumption that agricultural and industrial water demands are both function of the population size.

All, I'm saying is why (B) is better than (E) when answer choice (B) does not stand on its own and it needs a series of presumption to be a correct answers?

Thing is, (B) doesn't need a presumption to be correct. You're saying it assumes that water will be hard to move from region to region. Even if it's easy, though, it's still a hurdle that would need to be cleared. Introducing a hurdle to accomplishing something will necessarily make it less likely that that thing will be accomplished. In short, it's not an assumption to say that moving water will be harder to do than not moving water.

[azizbaba]

If you're trying to say that (E) tell us that 'water demand is a non-linear function', then the variables involved are 1) agricultural water demand and 2) industrial water demand. Neither of those is population.

agricultural and industrial water demands vary based on the population size. the answer choice (e) does not explicitly say that, same as answer choice (b) that does not explicitly say that the regions are not connected.

An example of answer choice (E) implication would be:

agricultural water demand= x^10 + m
industrial water demand=12x + n
total water demand= x^ 10 + 12X + K
(x is the population size)

[bp shinners]

If you're trying to say that (E) tell us that 'water demand is a non-linear function', then the variables involved are 1) agricultural water demand and 2) industrial water demand. Neither of those is population.

agricultural and industrial water demands vary based on the population size. the answer choice (e) does not explicitly say that, same as answer choice (b) that does not explicitly say that the regions are not connected.

An example of answer choice (E) implication would be:

agricultural water demand= x^10 + m
industrial water demand=12x + n
total water demand= x^ 10 + 12X + K
(x is the population size)

How do you know that population size plays into agricultural and industrial water demands? Maybe they're using processes that are cheaper, yet require more water, despite serving the same population size.

(B) doesn't need to say the regions aren't connected - they're explicitly different regions. They can be connected and (B) is still the answer.

[azizbaba]

Thing is, (B) doesn't need a presumption to be correct. You're saying it assumes that water will be hard to move from region to region. Even if it's easy, though, it's still a hurdle that would need to be cleared. Introducing a hurdle to accomplishing something will necessarily make it less likely that that thing will be accomplished. In short, it's not an assumption to say that moving water will be harder to do than not moving water.

Answer choice (B) relays on a big presumptions that regions are not connected. Let's compare it with this example:

Smith family will not face financial hardship in the near future to meet their needs because they currently use only a small fraction of their family income:
which of the following, if true, most seriously weakens the argument above?

B) Ms. Smith and Mr. Smith incomes vary significantly
E) The amount of money Smith family requires for their food grows much faster than the amount of money they need for leisure activities.

[bp shinners]

Thing is, (B) doesn't need a presumption to be correct. You're saying it assumes that water will be hard to move from region to region. Even if it's easy, though, it's still a hurdle that would need to be cleared. Introducing a hurdle to accomplishing something will necessarily make it less likely that that thing will be accomplished. In short, it's not an assumption to say that moving water will be harder to do than not moving water.

Answer choice (B) relays on a big presumptions that regions are not connected. Let's compare it with this example:

Not at all. Even if they're connected, that doesn't mean we can magically whisk water between them. They could be neighbors, and it would still take effort to move water.

[Christine (MLSAT)]

If you're trying to say that (E) tell us that 'water demand is a non-linear function', then the variables involved are 1) agricultural water demand and 2) industrial water demand. Neither of those is population.

agricultural and industrial water demands vary based on the population size. the answer choice (e) does not explicitly say that, same as answer choice (b) that does not explicitly say that the regions are not connected.

An example of answer choice (E) implication would be:

agricultural water demand= x^10 + m
industrial water demand=12x + n
total water demand= x^ 10 + 12X + K
(x is the population size)

That's one possible implication.

Or maybe it's this:

agricultural water demand = X
industrial water demand = x/2
(Where X is population)

Or maybe it's this:

agricultural water demand = Y
industrial water demand = Y/2
(Where Y = the age of my niece)


Some of those situations have agricultural water demand possibly becoming a problem, and some don't - but how the industrial water demand fits in is irrelevant. We could strike out that line entirely on all the examples and have the same issues.

How the industrial water demand and the agricultural water demand relate to each other doesn't give us any interesting information about how they relate to population.

[azizbaba]

Some of those situations have agricultural water demand possibly becoming a problem, and some don't - but how the industrial water demand fits in is irrelevant. We could strike out that line entirely on all the examples and have the same issues.

How the industrial water demand and the agricultural water demand relate to each other doesn't give us any interesting information about how they relate to population

some of the scenarios how water supply network works among earth regions may lead to difficulties, some may not. one possible scenario that the current unequal regional distribution is the best way for humankind to reserve the water supply may actually strength the argument.

[Christine (MLSAT)]

Some of those situations have agricultural water demand possibly becoming a problem, and some don't - but how the industrial water demand fits in is irrelevant. We could strike out that line entirely on all the examples and have the same issues.

How the industrial water demand and the agricultural water demand relate to each other doesn't give us any interesting information about how they relate to population

some of the scenarios how water supply network works among earth regions may lead to difficulties, some may not .

Okay, let me bring back the lottery ticket from above. You know the winning ticket starts with a 7.

Some tickets that start with a 7 win, and some don't.
Some tickets that are blue win, and some don't.

Which of these would strengthen the idea that your lottery ticket is likely to win?
1) Your ticket starts with a 7.
2) Your ticket is blue.



*** Edited to add***
The turning point between these is not whether there are still scenarios that may or may not work. It's whether the given information actually affects the chances. The blueness of the lottery ticket doesn't affect anything at all. The fact that it starts with a 7 though, seriously increases your likelihood of winning.

The same thing is going on here. The relationship between agricultural water demand and industrial water demand just doesn't have anything to do with the potential for water shortages based on population. However, if some regions have a lot less water than other regions, that affects the chances - it makes it just a bit more likely we'll hit some population-based water shortages in those regions. It's not a guarantee - maybe we'll develop instant water teleportation that's free and simple.

Imagine you're looking at two worlds - one has perfectly equal water access in all regions. The other has some deserts and some rain forest, etc. Which world is more likely to have have some local water shortages? All other things being equal, I'd put my money on the desert/rain forest world being a bit more likely than the other world to have local water shortages in some places. Again, not a guarantee.

Now, imagine you're looking at two worlds - one where the agricultural water demand grows faster than industrial water demand, and one where they grow at the same rate. Which one is more likely to have water shortages? I have no idea. That relationship just doesn't tell me anything at all.

[azizbaba]

Some of those situations have agricultural water demand possibly becoming a problem, and some don't - but how the industrial water demand fits in is irrelevant. We could strike out that line entirely on all the examples and have the same issues.

How the industrial water demand and the agricultural water demand relate to each other doesn't give us any interesting information about how they relate to population

some of the scenarios how water supply network works among earth regions may lead to difficulties, some may not .

Okay, let me bring back the lottery ticket from above. You know the winning ticket starts with a 7.

Some tickets that start with a 7 win, and some don't.
Some tickets that are blue win, and some don't.

Which of these would strengthen the idea that your lottery ticket is likely to win?
1) Your ticket starts with a 7.
2) Your ticket is blue.

Answer choice (B) is more like saying that the your ticket starts with 7 without saying the winning ticket starts with 7.

One possible implication of answer choice (B) may actually strength the argument, the implication that the current unequal regional distribution is the best way for humankind to reserve the water supply.

I'd put my money on the desert/rain forest world being a bit more likely than the other world to have local water shortages in some places. Again, not a guarantee.

This is your bet and assumption. Nothing about answer choice (B) without a set presumptions would weaken or strengthen the argument.

The turning point between these is not whether there are still scenarios that may or may not work. It's whether the given information actually affects the chances.

The correct answer choice for a weakening question should not just affect the chances, rather it should affect the chances negatively.

[Christine (MLSAT)]

Answer choice (B) is more like saying that the your ticket starts with 7 without saying the winning ticket starts with 7.

One possible implication of answer choice (B) may actually strength the argument, the implication that the current unequal regional distribution is the best way for humankind to reserve the water supply.

Okay, consider how the original argument is constructed. Remember that the weakener doesn't just make the conclusion less likely in a vacuum, it damages the connection between the premise and the conclusion.

• 
  Premises:
  Population is increasing
  current population only uses a tiny fraction of total Earth water
  Conclusion:
  No way we're going to have water shortages in the near future

The author is relying on the idea that the total population only uses a tiny part of the total water supply to support the idea that there won't be any water shortages. How could we live in a world where it's true that in total we only use a small fraction, but we still get water shortages soon? The total Earth water supply doesn't help a village in the middle of an area experiencing a localized drought.

(B) is zeroing in on the idea that it would be dangerous to make blanket predictions about water shortages based only on total numbers.

Arguments always assume their premises are enough to guarantee the conclusion. So this argument assumes that the adequacy of the total water supply (premise) is enough to guarantee that we'll have no water shortages. In other words, the argument assumes that the total water supply adequacy is reflective of that same adequacy in each region. What if it isn't? Then the conclusion is in doubt.

(B) doesn't guarantee that some regions are inadequate, it just raises the possibility, and makes it more likely. That's all it has to do.

[azizbaba]

doesn't guarantee that some regions are inadequate, it just raises the possibility, and makes it more likely. That's all it has to do.

The fact that how water supply is distributed is not discussed in the argument. So, in order to make it relevant and interpret from answer choice (B) that the current unequal regional distribution is increasing the likelihood of water shortage require you to bring your own presumptions from outside of the argument. You are assuming that the winning ticket starts with 7.

One possible interpretation of the answer choice (B) with a different set of presumptions than yours would be that the current unequal regional water distribution is ideal for the near future demand. We do not have any relevant information from inside of the argument to judge which interpretation is better.

[Christine (MLSAT)]

doesn't guarantee that some regions are inadequate, it just raises the possibility, and makes it more likely. That's all it has to do.

The fact that how water supply is distributed is not discussed in the argument. So, in order to make it relevant and interpret from answer choice (B) that the current unequal regional distribution is increasing the likelihood of water shortage require you to bring your own presumptions from outside of the argument. You are assuming that the winning ticket starts with 7.

One possible interpretation of the answer choice (B) with a different set of presumptions than yours would be that the current unequal regional water distribution is ideal for the near future demand. We do not have any relevant information from inside of the argument to judge which interpretation is better.

The argument assumes that global water supply adequacy is enough to guarantee no water shortages. If some regions are not reflective of that global water supply adequacy, the connection between the premise and the conclusion is damaged. If that's true, the fact that the global water supply is more than adequate becomes particularly flimsy evidence on which to base the conclusion. That's all a weakener has to do.

The reality is the (E) has absolutely nothing to do with the argument at all.

[azizbaba]

If some regions are not reflective of that global water supply adequacy,

That's a big IF, answer choice (B) doesn't say anything about adequacy.

The reality is the (E) has absolutely nothing to do with the argument at all.

Answer choice (E) is equally worse/good as answer choice (B) because some interpretations of it can weaken the argument.

[Jeffort]

(B) attacks the assumption of the argument and therefore weakens, (E) doesn't address the assumption, end of story.

azizbaba, you are failing to understand how weaken questions work. The argument is always flawed because it makes an unwarranted assumption and the correct answer choice undermines that assumption, thereby breaking the connection between the given premises and conclusion.

Here the argument jumps from the premise of plentiful supply to concluding that even with continued population growth, there won't be shortages of water available to people, hence assuming that there will be water available to people WHEREVER on the planet population grows/expands. What if one of the current population growth trends is an increase of people in the Sahara desert? Even though there is plenty of water supply overall on the planet, that doesn't mean it is easily available in all parts of the planet. (B) attacks the assumption that because plenty of supply, it will be easily available anywhere the population grows.

[Otunga]

because some interpretations of it can weaken the argument.

If only some can weaken it, then that's how you know it's wrong. Correct answers on these questions weaken for sure. Wrong answers, at best, only weaken given unjustifiably liberal interpretations.

[azizbaba]

(B) attacks the assumption of the argument and therefore weakens, (E) doesn't address the assumption, end of story.

answer choice (B) attacks which assumption?

the argument does not assume that the water is distributed equally among regions.

answer choice (E) attacks the argument assumption that the water demand is not going to grow exponentially by suggesting that some elements that constitute the total water demand (agricultural water demand and industrial water demand) grow at different rates.

[azizbaba]

What if one of the current population growth trends is an increase of people in the Sahara desert? Even though there is plenty of water supply overall on the planet, that doesn't mean it is easily available in all parts of the planet.

the argument has mentioned explicitly that it's only valid if the current population growth trends will not change.

what if the current unequal regional distribution will enhance humankind in the near future to meet water demand?

The correct weakening answer choice should reduce the likelihood of the event discussed in the argument. Answer choice (B) can increase the likelihood of the event with a different phenomenological approach.