LSAT and Law School Admissions Forum

Get expert LSAT preparation and law school admissions advice from PowerScore Test Preparation.

 Administrator
PowerScore Staff
  • PowerScore Staff
  • Posts: 8950
  • Joined: Feb 02, 2011
|
#1936
Complete Question Explanation

Flaw in the Reasoning, CE. The correct answer choice is (C)

Premise: Many symptoms of mental illnesses are affected by organic factors such as a deficiency in a compound in the brain.
PT62 - LR2 #13 diagram 1.png
Premise: The symptoms of mental illness vary among different countries.

Conclusion: The organic factors that affect symptoms of mental illnesses are not distributed evenly around the globe.

The relationship between the second premise and the conclusion is also causal, which can be diagrammed as:
PT62 - LR2 #13 diagram 2.png
The conclusion, which is easy to spot due to the conclusion indicator “this variation establishes that,” is based on the finding that the incidence of symptoms in people with mental illness varies among different countries. Because organic factors can affect the symptoms of mental illness, the author attributes the variation in symptoms to an uneven distribution (i.e. variation) of organic factors around the globe. Literally, the author believes that different symptoms in different places are the result of what organic factors are present, and the variation in those symptoms shows that the organic factors are not distributed evenly.

Arguments that draw causal conclusions are inherently flawed because there may be another explanation for the stated causal relationship. Take depression, for instance. If doctors treat depression differently in the U.S. than in Japan, then it is quite possible that depression would manifest itself differently in the U.S. than it would in Japan, because some treatments may be better able to control certain symptoms better than others. Cultural factors may also play a role in how the symptoms of depression are being reported. Because the author author assumes that there is only one cause for the variation in the incidence of symptoms in people with mental illness, you should attack the answers looking for a description of this error.

Remember—the key to determining the error of reasoning is to focus on the connection between the premises and the conclusion, not on whether the premises are factually true. In this instance, it would have been counterproductive to doubt whether organic factors can indeed affect the symptoms of mental illness, since the causal relationship between the two functions as a premise and should not be questioned. Instead, focus on how the premises were used to support the conclusion.

Answer choice (A): Although the author does not specify exactly how many different mental illnesses are being discussed, this is not a flaw. An author is not required to specify every single fact or statement within in an argument. The conclusion would be equally strong regardless of how many mental illnesses are being discussed.

Answer choice (B): This is an attractive answer at first glance because some students see the nutritional element as an alternative explanation for the variation in symptoms. Even if nutrition contributed to deficiencies in compounds in the brain and nutritional factors varied from culture to culture, this would most likely be an effect of the uneven distribution of organic factors (foods eaten vary from culture to culture, and are often largely based on what is available locally or regionally). As this answer describes another effect of the cause, this answer does not describe a flaw in the argument. Note that, even if you dispute that this is an effect of the cause, this answer would still not describe an error in the argument or show that organic factors are not responsible for the variation in symptoms.

Answer choice (C): This is the correct answer choice. If cultural factors significantly affect how mental illnesses manifest themselves in symptoms, this would provide an alternate cause for the observed variation among different countries in the incidence of symptoms in people with mental illness. The possibility that an alternate cause can explain the given effect challenges the implicit assumption that there is only one cause for that effect, thereby making the reasoning vulnerable to criticism.

Note that the idea in answer choice (C) could have been phrased in many different ways:
  • “takes for granted that cultural factors do not significantly affect how mental illnesses manifest themselves in symptoms”

    “presumes, without justification, that no other factors can significantly affect the manifestation of mental illnesses”

    “ignores the possibility that some other factor can affect the incidence of symptoms in people with mental illnesses”

    “fails to exclude an alternative explanation for the observed effect”
As always, it is important to identify the logical flaw in causal reasoning, but do not assume that there is only one way to describe that flaw. Be flexible with your prephrase.

Answer choice (D): At first, this may seem like an attractive answer choice, since it describes a possible unwarranted assumption. However, the author never implied that any change in brain chemistry would manifest itself as a change in mental condition. If she made that assumption, its logical opposite would have to weaken the conclusion. It does not. Even if some changes in brain chemistry did not manifest themselves as changes in mental condition, this would be consistent with both the premise and the conclusion of the argument. After all, the premise stated that many symptoms of mental illnesses are affected by deficiencies in a compound in the brain, not general changes in brain chemistry.

Since the statement described in answer choice (D) is not necessary for the conclusion of the argument to be logically valid, it is not an assumption.

Answer choice (E): The author never discussed whether the causes of mental phenomena are only physical phenomena; the scope of the argument was limited to the causal relationship between organic factors and symptoms of mental illnesses. Furthermore, it would be relatively easy to check if the author made this assumption by examining whether its logical opposite weakens the conclusion. It does not. Even if mental phenomena were not simply manifestations of physical phenomena, this would be consistent with the conclusion that the variation of symptoms of mental illness is due to a variation in the organic factors that affect them.
You do not have the required permissions to view the files attached to this post.
 emilysnoddon
  • Posts: 64
  • Joined: Apr 22, 2016
|
#25650
I read the above explanation and while it was very helpful in understanding why C is correct I am still a bit confused about B. Since nutritional factors are contributing to deficiencies in compounds in the brain does this mean that this is still an organic factor and therefore doesn't weaken?
 Nikki Siclunov
PowerScore Staff
  • PowerScore Staff
  • Posts: 1362
  • Joined: Aug 02, 2011
|
#25841
Hi Emily,

I wasn't able to understand your question about answer choice (B), but I'm confident that the explanation provided is thorough enough:
Answer choice (B): This is an attractive answer at first glance because some students see the nutritional element as an alternative explanation for the variation in symptoms. Even if nutrition contributed to deficiencies in compounds in the brain and nutritional factors varied from culture to culture, this would most likely be an effect of the uneven distribution of organic factors (foods eaten vary from culture to culture, and are often largely based on what is available locally or regionally). As this answer describes another effect of the cause, this answer does not describe a flaw in the argument. Note that, even if you dispute that this is an effect of the cause, this answer would still not describe an error in the argument or show that organic factors are not responsible for the variation in symptoms.
If any specific element of this explanation is still confusing, or can persuasively argue that answer choice (B) should still be correct, by all means - fire away :-)

Thanks,
 zookeeper
  • Posts: 1
  • Joined: Sep 07, 2017
|
#39344
I'm very confused as to how E is incorrect. How aren't organic factors as physical compounds within the brain viewed as physical phenomena? Especially when opposed to non physical, such as culture. C struck me as too narrow in scope relative to E which mentioned all other possibilities as a whole relative to one exact overlooked possibility that is C. Additionally, when E is negated with the notion that physical phenomena are indeed organic factors, it does negatively impact the argument, preventing premise to conclusion.
 nicholaspavic
PowerScore Staff
  • PowerScore Staff
  • Posts: 271
  • Joined: Jun 12, 2017
|
#39393
Hi zookeeper,

Great question! I think that the negation discussed in the explanation above may be where the problem is occurring for you in the question. Note that proper negation would not be the complete polar negation which you propose. It is that mental phenomena are not only manifestations of physical phenomena or as referenced in the explanation above, "even if mental phenomena were not simply manifestations of physical phenomena." Therefore, checking if this assumption contained in Answer Option (E) negates the conclusion that organic factors that affect symptoms of mental illnesses are not distributed evenly around the globe, it in fact, does not.

Also, one word of caution for people who are reading this exchange. Many students after learning the Assumption Negation technique for Assumption type questions mistakenly think that they can start using this technique for many other types of questions for which it is not effective. Answer Option (E) here, is certainly phrased as an assumption, and so it's negation will provide the test taker an effective means for eliminating it in this specific instance, but that isn't the case for all Flaw questions or for example, Justify questions where students will often try to unsuccessfully apply it.

Thanks again for the great question.
 kcho10
  • Posts: 68
  • Joined: Nov 02, 2015
|
#42764
Hi,

I have another question about (B). If the nutritional factors did not vary from culture to culture, and answer choice B instead said 'neglects the possibility that nutritional factors contribute to deficiencies in compounds in the brain' would it still be incorrect? I am thinking this would still be incorrect because it is only explaining what caused the deficiencies in compounds, which wouldn't weaken the idea that compounds affect the symptoms of mental illness. In other words, I'm asking whether explaining the cause of B weakens the idea that B caused C

Thank you!
 Adam Tyson
PowerScore Staff
  • PowerScore Staff
  • Posts: 5377
  • Joined: Apr 14, 2011
|
#42801
kcho, I'm with you all the way there! Even that proposed change to answer B would still leave it as a weaker choice than answer C because it wouldn't address the issue of varying levels of organic factors (whatever they are, they could still be evenly distributed). Part of the problem is addressed by our explanation at the top of the thread, and that is that "nutritional factors" may, in fact, BE "organic" factors. What we really need, and what we should prephrase, is variation in some clearly NON-organic factors, and that's where answer C takes the prize. Cultural factors are non organic factors - they are artificial constructs - and so they truly represent an alternate cause for the variation.

Good thinking, keep that up!
 ieric01
  • Posts: 34
  • Joined: Dec 09, 2019
|
#72492
It was challenging to see what was wrong with the argument.

Anyway, here's my take on it.

I'd love if anyone can tell me if this was the right way or wrong way to think about it.

=====

The author is establishing a causal relationship between symptoms and organic factors. Since symptoms vary around the world, then organic factors must also vary. Can we guarantee this to be true? Can we say that if a mentally ill person is not displaying symptoms or in the way they should, then they are not affected by an organic factor? No.

Here’s an example:

Let’s say a group of people from country A were all deficient in dopamine (our organic factor) which causes sadness (our symptom). If they didn’t display sadness, can we absolutely be sure they are not deficient in dopamine? No. There are a number of reasons why they might not show sadness. Perhaps their culture teaches them to always put a smile on no matter what you’re going through. Perhaps their culture associates being sad with weakness, so they put their ‘tough’ face on even in times of despair. If that’s the case, then their culture influences how mental illnesses manifest themselves in symptoms. The symptoms could vary but the organic factors may not.
 Claire Horan
PowerScore Staff
  • PowerScore Staff
  • Posts: 408
  • Joined: Apr 18, 2016
|
#72499
Hi ieric01,

Yes, your post does a good job of illustrating the Administrator's explanation for why answer choice C is correct: an argument that assumes there is only one cause for a given effect can be weakened by showing that alternate causes have not been considered.

Nice job thinking through the flaw in the reasoning!
 ieric01
  • Posts: 34
  • Joined: Dec 09, 2019
|
#72539
Thank you, Claire, for your feedback!

Anyhow, I hope this helps someone! Below is why I thought the other choices were wrong. Feel free to correct me if something was wrong in my reasoning or if you have any questions.

=====================

A) does not say how many different mental illnesses are being discussed

The author doesn't have to specify how many different illnesses he was talking about. He could be talking about 100 different mental illnesses and the argument would still stand. Just because he didn’t specify something doesn’t make his argument flawed.

B) neglects the possibility that nutritional factors that contribute to deficiencies in compounds in the brain vary from culture to culture

Yes, nutritional factors can vary from culture to culture. But how does that weaken the argument? You might say “If people are not getting the same nutrition in every culture, that could be why their symptoms are different.”

My response:

You’re right. The difference in nutrition could explain why the symptoms are different. But we know this already. The author says “organic factors like deficiencies in a compound in the brain affect symptoms of mental illness.” These nutritional differences is another example of organic factors. In fact, it strengthens the premise that organic factors cause these symptoms. But it doesn’t give a competing explanation of how a variation in symptoms could be caused by something else. If there’s another plausible cause, then we can’t definitively assume that any variation in symptoms will cause a variation in organic factors. One could change, the other may not.

(C) fails to consider the possibility that cultural factors significantly affect how mental illnesses manifest themselves in symptoms

This choice offers an alternative explanation of why symptoms may vary. What is it? Culture. It can have a big influence on a person. Let’s assume a group of people from Country A are deficient in dopamine (our organic factor) which causes sadness (our symptom).

Now, let’s talk about their culture or way of life. Let’s say one of their beliefs is to “Always keep a smile on and march forward.” If that’s what they believe, then depression can manifest itself differently than what is usual. However, they can still be deficient in dopamine. Simply because they don’t show symptoms or in the way they should, it doesn’t guarantee they’re not deficient in dopamine. The symptoms could vary but the organic factors may not.

D) presumes, without providing justification, that any change in brain chemistry manifest itself as a change in mental condition

The author never assumes this. He’s only concerned with changes that have occurred in the brain and have caused a change in their mental condition not just any change in brain chemistry.


E) presumes, without providing justification, that mental phenomena are only manifestations of physical phenomena

I had trouble with this one. As far as I know, the author never mentions anything about physical phenomena. And what does that even mean?

Get the most out of your LSAT Prep Plus subscription.

Analyze and track your performance with our Testing and Analytics Package.