LSAT Discussion Forum

Complete Question Explanation

Parallel Flaw. The correct answer choice is (A)

The flawed argument here is basically this:

Premise: Studies show that eating fruits and vegetables is healthy, and there were a few vegetables here and there that were not organic.

Conclusion: This proves that organic and inorganic are equally healthy.

This represents a fairly unique type of flaw. The author has referenced instances of benefit from a mix of two things, and then concludes that the two are equivalent.

Answer choice (A): This is the correct answer choice. As with the stimulus, the author in this case discusses an instance of benefit from power plants, nuclear and non-nuclear, and then concludes the two types to be equivalent in safety.

Answer choice (B): The flaw here is that there is no way to assess or compare the effectiveness of dietary restriction based on the information provided. This is not the same type as found in the stimulus, so this answer choice is incorrect.

Answer choice (C): The problem with the reasoning in this stimulus is that the author makes an apples-to-oranges comparison—between motorcyclists with a year of training, and car drivers with almost no training. Although this author's conclusion is not valid, this does not represent the same type of flaw as that in the stimulus author's argument.

Answer choice (D): This argument draws an overly broad conclusion—that there is no difference in risk of using wood vs. plastic—without any information about the various microbes that may attack the different types of cutting boards. This is flawed, but different from what we're looking for, so this answer choice is incorrect.

Answer choice (E): This argument does not parallel the reasoning found in the stimulus. This argument is as follows:

Premise: Health-wise, vitamins are equivalent to a small increase in fruits and vegetables.

Conclusion: Thus, there is no health risk in not taking vitamins as long as one is getting enough fruits and vegetables. Since this conclusion is valid, this answer choice cannot be correct.

I have no idea how the HW explanation for Question 25 (below) determines the conclusion has to do with organic versus inorganic. I did not get the point that the flaw has to do with the organic/inorganic. So, I need a better explanation of this question, or, at least I need someone to explain to me two things: why is the conclusion not about the zero increase in health risk associated with eating fruits and vegetables containing pesticide residues, and what exactly is the flaw in this question. I have attached the HW explanation that accompanies the Homework lesson to show that I am somehow not getting a piece of crucial information.

Homework Explanation:
"The flawed argument here is basically this:
Premise: Studies show that eating fruits and vegetables is healthy, and there were a few vegetables here and there that were not organic.
Conclusion: This proves that organic and inorganic are equally healthy.
This represents a fairly unique type of flaw. The author has referenced instances of benefit from a mix of two things, and then concludes that the two are equivalent."

Hi rdixon!

You are correct that the conclusion is that last sentence, that there is not any increased risk with eating fruits and vegetables with pesticide residue. The conclusion in the explanation is just another way of stating that. Fruits and vegetables that have pesticide residues are nonorganic. So the conclusion is that there is no increased risk from eating fruits and vegetables with pesticide residue (nonorganic) as opposed to eating fruits and vegetables without pesticide residue (organic). If there is not an increased health risk with nonorganic fruits and vegetables, then the organic and nonorganic fruits and vegetables are equally healthy.

As the explanation states, this is a unique flaw that is not one of the common flaws listed in the lesson. Essentially, the author says that since studies showing that eating more fruits and veggies may help decrease the incidence of cancer do not distinguish between organic and nonorganic, that we can therefore conclude that there is no health difference between organic and nonorganic. But this may not be the case. Maybe the incidence of cancer would have been even lower for people who ate only organic produce vs. people who ate only nonorganic produce. Just because the studies didn't distinguish between the two types of produce, doesn't mean we can assume that the two types are basically the same.

Hope this clears things up!

Best,
Kelsey

Thanks Kelsey! That clears everything up for me. Have a good weekend.

Kristin asked:

""Studies showing the increased consumption of fruits and vegetables.."
Are we assuming the non-organic foods as the one containing the pesticide? And I saw this argument online and for some reason it makes more sense to me, but I do not know if it is valid, could someone confirm?

The author takes

Consume produce in general-->decrease incidence of some cancer

to mean

consume non-organic produce (pesticide residue)--> no increase in overall health risk.

and this parallels answer choice A, since it can be diagrammed as:

Modem power plant-->decrease incidence of certain major illnesses

to mean

nuclear power plant--> no increase in overall health risk.

Is this a correct abstraction therefore: Just because two kinds of things can have identical beneficial aspects (reduction of cancer) does not mean that one of the two comes without any health risks whatsoever (i.e. the non-organic foods w/ the pesticide)

I think your analysis here is very, very close, but I would clarify one point: the author does not provide evidence that the benefits from two things (organic vs non-organic, nuclear vs. non-nuclear) are identical. Rather, he looks at the cumulative effect of both, failing to distinguish one from the other, and then concludes that both are equal (and as you correctly pointed out, he leaps from "some" benefit all the way to "no harm" without justification). This strikes me as an error of division - just because the whole (fruits and veggies in the stimulus, modern power in the correct answer) has a certain characteristic, the author presumes that the parts also have that same characteristic.

Imagine a similar argument: "The combined movies of Disney and my cousin Fred's home movies have the highest overall grosses for the past 10 years, therefore my cousin Fred's movies had high grosses." Not so great, right?

I'm really just nit-picking here - as I said, I think you had a really good grasp on it to begin with, and I just wanted to clarify that it's the cumulative benefit being compared to the individual benefit that is the problem.

Nice work! Keep it up!

Wonderful response thank you!

Could you explain a bit more why E is valid? I'm unsure how to diagram it.

You stated that you had trouble diagramming E and understanding why E is valid.

(E) Research shows that there is no greater long-term health benefit associated with taking vitamin supplements than with a moderate increase in the intake of fruits and vegetables. Clearly, then, there is no long-term health risk associated with the failure to take vitamin supplements, so long as enough fruits and vegetables are consumed.

So the first sentence sets up that the benefits of vitamin supplements and the benefits of fruits or vegetables are the same.
The conclusion, in the second sentence, is that to replace one with the other poses no risk. Since we know from the premise that the health benefits of both options are the same, it is valid to conclude that replacing one with the other does not carry greater risk.

I hope that is helpful. Good luck in your studies!
Dan

Since this is a unique type of flaw, I want to make sure I fully understand it. Could someone please give another similar example of this type of flaw or point me in the direction of other similar questions?