#20 - Pretzels can cause cavities. Interestingly, the longer

[Administrator]

Complete Question Explanation

Flaw in the Reasoning. The correct answer choice is (A)

In this stimulus a comparison is set up between caramels and pretzels, according to one characteristic. They both cause cavities and their likelihood of causing a cavity increases the longer they remain in contact with the teeth. The second premise states that caramels dissolve more quickly than pretzels. Then, the conclusion states that a caramel is less likely to cause a cavity than a pretzel. Read this stimulus and React! Of course, a sugary caramel is more likely to cause a cavity, but where is the reasoning flaw? The conclusion of this argument would only follow if all characteristics of pretzels and caramels were exactly the same (which we know not to be true). Because pretzels and caramels share one characteristic, this author assumes that they share all others as well.

Answer choice (A) This is the correct answer choice. Simply because caramels and pretzels are correlated in one way at the beginning of the stimulus does not mean that this correlation holds true for other categories, such as sugar content.

Answer choice (B) This is a common answer choice given in Flaw questions, and can be correct at times. However, in this stimulus there are no terms used in different or ambiguous ways.

Answer choice (C) This answer may tempt some test takers because the conclusion does seem like a generalization. However, the author is not citing pretzels and caramels as representative of some larger groups (for instance snacks vs. candy). This stimulus is not dealing with "classes" but only with caramels and pretzels. Therefore, this answer choice cannot be the correct answer. (Remember, Flaw questions are in the Must Be True family).

Answer choice (D) The stimulus is not concerned with arguing about cause and effect. Yes, the foods are cited as causes of cavities, but the conclusion is not concerned with causal statements. It is making a comparison between these two causes. The effect does not matter.

Answer choice (E) Do not answer this simply because you know by commonsense that the conclusion is not true and feel like the reasoning is solid. Looking at each premise individually demonstrates that each could possibly be true. The conclusion does not follow because of the flaw mentioned above. There is nothing incorrect in the premises.

[alee]

Hi,

I have a question about Q20. Dec 1994 (Section II). I understood the stimulus as follows:
1. Pretzels can cause cavities + the longer a pretzel remains in contact with teeth, the greater the likelihood of a cavity.
2. What is true of pretzels in this regard is also true of caramels.
3. Caramels dissolve more quickly than pretzels
Conclusion: eating a caramel is less likely to result in a cavity than eating a pretzel is.

My logic was that 'dissolving more quickly' is treated as equivalent (without sufficient justification) to 'remaining in contact for less time than pretzels', and accordingly selected (B), thinking 'remaining in contact' to be the key term used in an ambiguous way.

However, the answer is actually (A): 'treats a correlation that holds within individual categories as thereby holding across categories as well'. I can see how this is a criticism of the argument, but my problem is that this option seems to attack one of the premises of the argument itself, namely (2) (see above.). But a principle from the Logical Reasoning Bible is that we are take the premises as 'given'.

Could you please explain why A is the right answer?

Thanks for all the fantastic help, I'l be appreciating it when I sit the June Lsat!

[Jon Denning]

Hey alee- thanks for the question. I'll discuss A and B here in hopes that that will clear things up. For A, you can certainly have a flawed argument (as we have here) based off of a failure of the premises to prove the conclusion, so describing that failure isn't so much an attack on the premise as it is a description of the argument's weakness. So we can take the information in the premises as true (pretzels cause cavities, etc), but we must question whether that information validly leads to the conclusion given. In this case it doesn't, and that's what A is describing. Be careful not to confuse attacking factual information in a premise with merely outlining why that information doesn't prove the conclusion is true, which is what happens here.

For B, I can see your reasoning behind choosing it, however this Uncertain Use of a Term flaw will tend to be much more explicit when it appears. That is, a key word or idea will generally be used two or more times, but either in very different ways each time or in such a way where it's clear that the meaning of it has changed. In this stimulus there's no ambiguity/uncertainty in the language, so B is incorrect.

I hope that helps!

[adlindsey]

I had this question between A & C and ultimately choose the latter. I don't quite get what the difference is between categories and classes? Also, just curious, how do you all work out these problems when one is presented for the first time? Do you all figure them out independently or consult with the test makers?

[Adam Tyson]

Thanks for the question, adlindsey. I'll take the second one first: no, we do not consult with anyone at LSAC in coming up with our explanations! That would be fun, getting directly into the heads of the folks creating the test. There may be some folks here at PowerScore that have the names and contact info for some of the test authors, but most of us (myself included) do not. Instead, we analyze the questions ourselves and come up with what we feel to be the best explanations for the correct answers. We sometimes disagree about what's the best way to do that, and we sometimes disagree about what type of question we are looking at (is it a Must Be True or is it an Assumption?), but we all agree on what the best answer is and we all do our best to help explain it to you all.

As to the first question, I would say that classes and categories are, in this case, synonymous. The issue between A and C isn't that choice of words, but is the meaning of the answer choices. A describes what happened in the stimulus, as the Admin response explains in the original post here. Something that is true within the category of things like pretzels (longer contact = more cavities) is also true in the category of things like caramels (ditto), and the author then improperly concludes that we can compare things across those categories (pretzel-like things to caramel-like things).

C describes an over-generalization based on unrepresentative samples. That's saying that information about, say, caramels is being used to come to a conclusion about all candies, when caramels may not be representative of candies generally (they may be atypical within that class of things).

I hope that puts this question into the class (or category) of things that now make more sense to you!

[adlindsey]

Got it. You're breakdown of C makes sense. Thank you!

[AspiringLawyer]

Is the type of error in this stimulus considered to be False Analogy?

[Eric Ockert]

Hi Aspiring Lawyer!

No, this wouldn't be a False Analogy. A False Analogy would be comparing two things that are just too dissimilar to really make a proper comparison. An example might be:

"Just as running a race car in the red can be rough on the car's engine, when Jonathan runs in his red Speedo, it's pretty rough on people's eyes."

Here, they properly show that there is a similarity between pretzels and caramels in one regard. The problem is that they then use that similarity to say that they must share a similarity in another regard. That's a bit different than a False Analogy.

Hope that helps!

[jessamynlockard]

Your reasoning for about sugar content makes A make sense, but without that I'm still not getting why A is the correct answer choice. Could "across categories" be referring to the amount of contact with the teeth vs. how quickly it dissolves?

As a previous poster commented, the distinction between amount of contact with the teeth vs. speed of dissolving was what tripped me up as well.

[Adam Tyson]

The categories here, jessamyn, are "things like pretzels" and "things like candies". We can't compare the two based solely on how long they remain in contact with the teeth/how quickly they dissolve (which I interpret as being essentially the same thing) because they may have other qualities that also impact the formation of cavities. So a caramel that stays in contact with your teeth for 5 minutes might do less damage than a caramel that stays in contact with your teeth for 10 minutes, but it could still do more damage than a pretzel that stays in contact with your teeth for 15 minutes. That could be due to sugar content, acids in the foods, the manner in which our bodies process the different food contents, etc. We can compare pretzels to pretzels and caramels to caramels, but we don't have enough info to allow us to compare them to each other. That's because they are not in the same category.

Now I'm hungry!