#2 - Archaeologist: For 2,000 years the ancient Sumerian

[Administrator]

Complete Question Explanation

Weaken—CE. The correct answer choice is (C)

In this stimulus, the archaeologist argues by analogy and causal reasoning. The stimulus begins
with the archaeologist telling us about the effects of the irrigation methods used by the Sumerians
for 2,000 years. Although the Sumerians were able to feed their civilization for 2,000 years because
of irrigation, ultimately the process caused toxic levels of salts and other impurities to build up
in the soil. These impurities, which are left behind when water evaporates, eventually made the
soil incapable of supporting agriculture. When that occurred with the Sumerians, their civilization
collapsed.

The archaeologist then moves on to talk about modern civilizations, concluding that modern
civilizations that rely heavily on irrigation for agriculture would likely suffer “a similar fate,”
meaning at least that the irrigated land will eventually become unable to support agriculture, and
possibly also that a modern civilization in such circumstances may collapse.
This argument is flawed, because it makes an assumption that is common to causal arguments
involving a long time span. It assumes that the circumstances that existed in Sumeria are sufficiently
similar to modern conditions to support an analogy between the two scenarios and to imply that the
same causal outcome is likely to occur. However, there may be several factors that distinguish the
circumstances in ancient Sumeria from modern circumstances.
This is a Weaken question. Our prephrase is that the correct answer choice will attack the conclusion
by showing some way in which the modern scenario is different than what occurred in Sumeria, such
that it is not the case that the same fate that the Sumerians experienced is likely to happen to modern
civilizations as well.

Answer choice (A): This answer choice explains why most modern civilizations depend on
irrigation, but does not tell us why the modern experience with irrigation will be any different that
what the Sumerians experienced.

Answer choice (B): The fact that soil contamination was not necessary to cause the fall of the
Sumerians does not attack the conclusion that the same thing will happen to modern civilizations.

Answer choice (C): This is the correct answer choice, because it tells us that modern farmers are
different than the Sumerians in a way that makes it less likely that the modern irrigated farmland will
become incapable of supporting agriculture. Rather than irrigation techniques being frozen in time,
many modern farmers do things differently, protecting the soil from the buildup of salts and other
toxic impurities.

Answer choice (D): This answer choice does not attack the conclusion, which does not depend on
numbers, but rather refers to “modern civilizations.”

Answer choice (E): This is an attractive incorrect answer choice because it implies alternate
causation. Perhaps the inherent characteristics of the Sumerian soil, and not the effects of irrigation,
led to Sumeria’s soil issue. However, the stimulus told us as a fact that the inability of Sumerian soil
to support agriculture resulted from irrigation. Even if there already was some level of impurity in
the soil prior to irrigation, that does not necessarily conflict with the stimulus’ assertion of fact that
irrigation caused the Sumerian’s inability to produce agriculture.

[pavalos5777]

Hello,

Can you please provide further explanation as to why answer choice D is not compatible with the pre-phrase?

In terms of the time error, it does show that modern civilizations, as opposed to the ancient Sumerians do not rely on irrigation for agriculture to any significant extent; whereas, the stimulus provides that "the ancient Sumerians depended on irrigation to sustain the agriculture that fed their civilization." This was conducive to the collapse of Sumerian civilization, after its soil became unable to support agriculture; if modern civilizations do not rely on irrigation to this extent, then they could avoid "a similar fate."

I believe this makes D a more attractive answer choice than E. I kept C and D as contenders and ultimately went with D for the reasoning cited above.

Much appreciated,
Pierre

[AthenaDalton]

Hi Pierre,

Thanks for your question!

The conclusion of the stimulus is that modern civilizations that continue to rely heavily on irrigation for agriculture will meet the same fate as ancient Sumeria. You're correct that civilizations which don't rely on irrigation for their agriculture will avoid the catastrophic salt build-up that ruined Sumerian farms. However, the argument accounts for that possibility by limiting its prediction of doom to agricultural systems that rely on irrigation.

The archaeologist's warning applies only to agricultural systems that continue to rely heavily on irrigation for agriculture. Therefore, answer choice (D) isn't on-point since it's talking about farms that don't use irrigation.

I hope that helps clarify things. Good luck studying!

Athena Dalton

[pavalos5777]

Thanks Athena, that helps!

[cindymoon14]

Hi,

Does the answer to this Weaken question have to attack the Archaeologist's conclusion as the passage says? I chose (B) as the answer because I believed it would weaken the basis for the cause of the Archeologist's argument, therefore weakening the entire argument. Or does (B) not weaken the argument because it renders the argument itself irrelevant rather than weakening the causal relationship?

I would appreciate further in-depth explanation of why (B) is wrong. Thank you in advance!

Best,
Cindy

[Shannon Parker]

Hi there cindymoon,

Yes, in a weaken question you are always looking for the answer choice that attacks or weakens the author's argument. In this case, B is an incorrect answer choice because it does not attack the author's argument. The author of the stimulus argues that 1. Ancient Sumerians depended on irrigation for their agriculture. 2. The irrigation caused toxic levels of salts and other impurities to build up in the soil. 3. When the soil became unable to support agriculture, the society collapsed. 4. Modern civilizations that rely on irrigation for agriculture will likely collapse. The first three statements are the premises upon which the conclusion relies and the fourth statement is the conclusion.

In a weaken question you can easily test a wrong answer choice by plugging it into the argument and judging the effect that it will have on the conclusion. Here if we plug answer choice B in as a premise, "Factors unrelated to the use of irrigation would probably have caused Sumerian civilization to collapse sooner or later" it has no effect on the conclusion. Whether some other factor would have caused the same outcome does not negate the causal relationship.

On the other hand, we can see that plugging answer choice C "Many modern farmers use irrigation techniques that avoid the buildup of salts and other toxic impurities in the soil" into the causal chain destroys the argument. If the cause of the collapse was because the soil could no longer support agriculture, due to the toxic level of salts and impurities, farming in a way that avoids the build up of those salts and impurities will allow the soil to continue supporting agriculture, thus avoiding the collapse of civilization.

Hope this clears it up.

[Sammiewhammie]

Hi,

Would AC E also be incorrect because it does not connect back to the conclusion about modern civilization?

Thanks,
Sammie

[atierney]

Hello,

Yes, I think that's one way of looking at it, and in the exam situation, any feature of an incorrect AC is a valid means for eliminating it. Just so long as it's truly incorrect!

Here, though the main issue is it's failure to attack the central causal nexus proposed in the answer choice. Let me know if you are unable to see why that part AC E makes it incorrect. Otherwise, yes, there is indeed more than one way to skin a cat!

[quan-tang@hotmail.com]

I find C a very unattractive answer because it says about farmer, not about civilization, which is different subject than the stem.
besides, many famer, but not all farmer. even if only a small proportion of farmer keep contributing to the toxic salt, it would eventually build up enough, just as what happened for sumarian. C does not weaken either.

[Luke Haqq]

Hi quan-tang!

You mention that answer choice (C) is "about farmers, not about civilization, which is different subject than the stem." The conclusion of the stimulus, however, as well as other parts of the stimulus, seems to encompass both farmers and civilization. The conclusion is: "A similar fate is thus likely to befall modern civilizations that continue to rely heavily on irrigation for agriculture." This refers to the agricultural practices of civilizations. In addition, the conclusion is specifically about agricultural practices of "modern" civilizations, and (C) is specifically about modern farmers.

To your point about the language of "many" modern farmers, it's true that it would weaken the conclusion even more if that language had instead been "most modern farmers." But the first usage still weakens the conclusion. It shows that modern agricultural practices have come to encompass at least some tools that mitigate the mentioned problem of a build up in the soil of toxic levels of salts and other impurities, and in addition, many farmers use these tools successfully.