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Mistake by LSAC? Pizzerias LR Sufficient Assumption Question.

xuzuqiaoxuzuqiao Core Member

Explanation (2 mins): https://7sage.com/lsat_explanations/lsat-40-section-1-question-21/

Question 21 on PrepTest 40 Section 1:
Pizzerias are the only restaurants that routinely record the names, addresses, and menu selections of their customers. Simply by organizing these data, they can easily identify regular, average, and infrequent customers. Therefore, pizzerias utilize direct-mail marketing more effectively than do other restaurants.

Which one of the following, if assumed, enables the argument's conclusion to be properly inferred?

The answer: Answer choice E
Restaurants that routinely record names, addresses, and menu selections of their customers always utilize direct-mail marketing more effectively than do any other restaurants.

What? How are we able to conclude such a strong statement?
From my understanding, the argument structure is very simple. The second sentence in this question is complete fluff. The first sentence provides the premise and the third sentence is the conclusion.

Let's use variables to diagram the logic:
A = Restaurants that routinely record
B = Pizzerias
C = Utilize direct-mail marketing more effectively

First sentence gives: A -> B (Restaurants that record -> Pizzerias)
Answer choice E provides: A -> C (Restaurants that record -> utilize direct-mail)
Conclusion says: B -> C (Pizzerias -> utilize direct-mail)

But using the premise in the first sentence and the assumption provided by the answer, we only get B some C. We can conclude that SOME pizzerias utilize direct-mail marketing more effectively than other restaurants. The conclusion is a general blanket statement that would include all pizzerias (I think).

What am I misunderstanding here? This question has been giving me a lot of headache, thanks to those who took the time to discuss in advance!

Comments

  • u______uu______u Alum Member
    233 karma

    You're overthinking it. This is a sufficient assumption question. All you need to do is provide an assumption that guarantees that the conclusion works. In many cases, yes, the sufficient assumption can be too strong. But, as long as it bridges the gap it's fine.

  • xuzuqiaoxuzuqiao Core Member
    edited September 2022 91 karma

    The assumption isn't too strong, it's the opposite that's happening here in this question. The conclusion is too strong - the correct answer does not provide a strong enough bridge to reach the conclusion. The assumption in answer E allows us to conclude a very weak conclusion - that SOME pizzerias utilize direct-mail marketing more effectively.

    The conclusion that we need to make valid is ALL pizzerias utilize direct-mail marketing more effectively.

    Does anyone know if this question ended up being tossed out? It seems like an oversight on LSAC's part and that they made a mistake.

  • KevinLuminateLSATKevinLuminateLSAT Alum Member
    edited September 2022 983 karma

    @dzxu88

    Can you go into why you're doing the first sentence as "Restaurants that record -> Pizzeria". This is the underlying issue - there may be an additional meaning contained in this statement that you're overlooking. If you're solely thinking about this in terms of "the only" = sufficient condition, is there another way to view what this sentence is saying?

    Jerry is the only person who comes into work on Mondays.

    Does that mean only the following: Comes into work on Mondays -> Jerry
    Is there anything else that this sentence is conveying?

    The state is the only entity that can take private property from someone without their consent.

    Is that "Can take private property from someone without consent -> The state"?
    Any other meaning that this sentence is conveying?

  • u______uu______u Alum Member
    233 karma

    @KevinLuminateLSAT

    Wow I have no idea how you can read those two statements in any other way. I wonder if I've been so conditioned by "the only" that my biases preclude other interpretations.

    @dzxu88
    Here's my take regarding your point about the conclusion. Not all pizzerias need to utilize direct-mail marketing. If no other restaurants routinely record etc., then having even one pizzeria that routinely records would make it valid to claim that pizzerias utilize direct-mail marketing more effectively than do other restaurants because of what E says. Similarly, if you're comparing a group of runners vs. a group of disabled people who can't walk, then you'd be fine saying that "runners are better at completing marathons than disabled people who can't walk are." Furthermore, we're only given the group, pizzerias, in the stim. The conclusion doesn't specify all pizzerias. There just needs to be some, as you said, pizzerias that do use direct-mail marketing more effectively than other restaurants. Most importantly, let's not forget that some can include a huge range, including all.

  • KevinLuminateLSATKevinLuminateLSAT Alum Member
    edited September 2022 983 karma

    @dzxu88 @u______u

    @"J.Y. Ping"(tagged for his thoughts on the issue)

    Interpreting the conclusion as a statement about "some" pizzerias would solve the OP's issue. But I actually think there's another resolution that's better and addresses multiple points of confusion.

    But to get there, I think we have to address 2 issues:

    (1) What does a plural subject mean - all, some, or perhaps something else?
    (2) Can the statement "the only" ever mean a bi-conditional?

    (1) What does a plural subject mean - all, some, or perhaps something else?

    As a general matter, we often treat plural subjects as referring to all of the group - that's why OP was interpreting the conclusion as applying to all pizzerias.

    Clearly, however, there are cases in which a plural subject may not make sense to interpret as referring to all of the group. If I say, "High school students are better at sports than first graders," is your first reaction really to think that I'm saying every single high school student is better at sports (all sports?) than every single first grader? Probably not. It also doesn't seem to mean only that some high school students are better at sports than some first graders. You'd probably interpret the statement as asserting something a bit stronger - generally, high school students are better at sports than first graders. Of course, it's entirely possible that there are very unathletic or otherwise physically incapable high school students who aren't better, and it's possible that there are supremely talented first graders who could beat most high school students - this wouldn't contradict the initial statement, right? I'm not asking for a certain and definite answer here - just suggesting that there may be a range of interpretations when you have a plural subject. (Notice how this type of plural subject + comparative statement is similar to the statements at issue in the pizzeria problem.)

    How about this one? "Humans are cruel."

    Is this asserting that every single human being is cruel? That every human, including a newborn baby, is cruel? Maybe. But it might be fair to interpret this as some, many, or most humans are cruel. Perhaps it's not even meant to be a some/most/all type of statement, but a statement about humans as a species. Is it possible that this statement is saying that, collectively, humans in their sense as a species are cruel, but the statement is not committed to saying anything about humans in their individual capacity?

    Could it depend on context? What if you saw this:

    "Humans are cruel. Thus, Paxton is cruel."

    The structure of the logic suggests that the missing piece is that Paxton is a human, and that I'm supposed to interpret the first statement as a conditional claim about all humans.

    But what about this:

    "Unlike other animals, humans are cruel."

    Would you interpret that as saying every single human being, including your grandmother, is cruel?

    I suspect you wouldn't - we're talking about humans in their species/group capacity, not as individuals.

    And so I suggest that in the pizzeria problem, a similar interpretation is justified. The initial statement about pizzerias is designed to contrast that kind of restaurant with other kinds of restaurants. We're not talking about pizzerias in the sense of "every single pizzeria in the world, including the millions of Dominos, Pizza Huts, Roundtable Pizzas, X-treme Pizzas, etc.". We're talking about pizzerias as opposed to burger joints and sushi bars and steakhouses and korean BBQs, and spicy crawfish shacks and so on. So it makes sense to interpret "pizzerias" in both the first sentence and the conclusion as referring to the kind of restaurant that makes pizzas. The use of "pizzerias" is not meant to refer to every single pizzeria in the world.

    I also don't think the "pizzeria" in the conclusion is meant only to mean "some" pizzerias - we're still talking about pizzerias as a contrast to other kinds of restaurants. I do think that a statement about pizzerias as a kind of restaurant probably implies something about at least some pizzerias in their individual capacity, but my point is that the conclusion is not just saying that there's at least 1 pizzeria that uses direct mail marketing more effectively than other restaurants. So this is why I find it to be unsatisfying to resolve OP's question by saying "Just interpret the conclusion as 'some pizzerias'".

    In any case, if you're with me so far that "pizzerias" is just about the kind of restaurant, then you could interpret the first sentence as follows: "The kind of restaurant that makes pizzas is the only kind of restaurant that routinely records..." And the conclusion would be "The kind of restaurant that makes pizzas uses direct mail marketing more effectively than any other kind of restaurant." See? The argument doesn't have to be about "all" or "some" or even "most" - it's just about comparing kinds of restaurants to each other.

    Now, we still have to deal with the issue of "the only".

    (2) Can the statement "the only" ever mean a bi-conditional?

    Generally, we're taught to treat "the only" as introducing the sufficient condition (or, that what it's referring to is the necessary condition). For example, "The only people who practice law passed the bar exam." This would be "Practice law -> passed bar." And it'd be wrong to think that this is saying that everyone who passed the bar is practicing law.

    Even if you change the order of the sentence, it doesn't change the meaning: "People who passed the bar are the only people who practice law." That means "Practice law -> passed bar." And it's not saying that everyone who passed the bar is practicing law.

    But a bit of ambiguity creeps in when we start coming up with examples that are about singular things as opposed to a plural subjects like "people who practice law". For example:

    "Vatican City, San Marino, and Lesotho are the only countries that are completely enclosed within another country."

    This does entail the following "Completely enclosed -> Must be one of those 3 countries". But surely you would agree that it's also saying that these three countries are in fact completely enclosed within another country, right? In other words, it's also saying

    VC -> Completely enclosed,
    SM -> Completely enclosed,
    L -> Completely enclosed.

    Let's come up with other examples:

    "Steak is the only food I plan to eat tomorrow."

    This does entail "Food I plan to eat tomorrow -> Steak". But are you really going to deny that this also means that I plan to eat steak tomorrow? If it didn't mean that, then the use of "is" just doesn't make sense in that sentence. You can actually just break this sentence in two:

    "Steak is a food I plan to eat tomorrow."

    And,

    "There is no food that I plan to eat tomorrow besides steak."

    The first one would be "Steak -> Food I plan to eat tomorrow"
    The second statement would be "Food I plan to eat tomorrow -> Steak"

    So technically speaking, it's not the phrase "the only" that's creating a bi-conditional here. Rather, the use of "is" is creating one part of the bi-conditional, and the phrase "the only" is creating the other part.

    At this point it's clear that a statement that uses "the only" can involve a bi-conditional. But I do want to address something that might be confusing: How is it that we can see the examples above as biconditionals, but there other uses of "the only", including in connection with singular entities and not plural subjects, where it does not seem to involve a biconditional?

    Take this example:

    "Hard work is the only way to be successful."

    Many of you will say that this clearly means "Successful -> Hard work" and clearly does NOT mean that hard work guarantees success. That's true, it doesn't mean that.

    But have you considered that this IS saying "Hard work -> way to be successful". So in that sense, we still have a biconditional. If it is a way to be successful, it must be hard work. And, if it's hard work, it is a way to be successful. The biconditionality does NOT apply when we speak about "being successful", but that's only because something that's a way to be successful does not guarantee success. If you speak about a "way to be successful" however, the meaning of the sentence is clear.

    In fact, if you really wanted to be as precise as possible (not that this is recommended), we shouldn't think of the statement as "Successful -> hard work". Instead, it should be this:

    "Way to be successful <--bi-conditional-> Hard work."

    Then, if someone happens to actually be successful, that would trigger the conditional, because if someone is successful, they must have had a way of being successful, which in turn implies hard work. This is how you get "Successful -> Hard work". Normally our minds just jump to that relationship of "Successful -> Hard work", but that's actually more like an inference based on the statement "Hard work is the only way to be successful" rather than a direct translation of the statement itself. Similarly, we recognize that this sentence does not mean "Hard work -> Must be successful". But many of us would explain the wrongness of that claim as related to a misinterpretation of "the only", when it's actually just an error related to the jump from "way to be successful" to actually being successful. If you said "Hard work -> Way to be successful", then that would be true.

    Now I really don't want to scare anyone or further confuse anyone - you shouldn't normally question the general handling of "the only" as presented by 7Sage and other LSAT curricula. I bring up the points above mainly because the pizzeria question the OP identified happens to be one (and perhaps the only one) for which a deeper understanding of "the only" might be necessary to avoid the confusion that OP felt.

    CONCLUSION

    So far I've established that "pizzerias" is meant in its "kind of restaurant" sense and that "the only" can involve a biconditional when the statement is about a singular entity. These points together can resolve the issue in the original post.

    "The kind of restaurant that makes pizza is the only kind of restaurant that routinely records...
    Thus, the kind of restaurant that makes pizza utilizes direct mail marketing more effectively than do other kinds of restaurants."

    The first statement can be seen as a biconditional:

    Kind of restaurant that makes pizza <-----> Routinely records

    The second statement would be:

    Kind of restaurant that makes pizza -----> Uses direct mail marketing better than other kinds

    Answer choice (E) gives us "Routinely records --> Uses direct mail marketing better than other kinds". If added to the argument, that would prove the conclusion.

    EPILOGUE

    I'm not saying that everything I wrote above is absolutely the one correct way to view things, although I do stand behind my reasoning and I hope it was both persuasive and enlightening. And, this kind of hyper-analysis is not at all recommended in the heat of doing an actual LSAT and struggling with what appears to be a confusing problem. In fact, with reasonable training, you can and should be able to get to (E) as your selection on this pizza problem confidently even if you think it's not perfect. But I think OP's confusion is a good example of what can arise when we're approaching things too mechanically. We shouldn't forget that there are ranges of meaning or ways to frame a particular relationship that can depend on context.

    In fact, even what you might call a basic, obvious conditional can be validly interpreted in multiple ways.

    In order to enter Taiwan, COVID vaccination is required.

    Everyone would say this means "Enter Taiwan -> Must have COVID vaccination", right?

    It does. But you can also focus on a different aspect of the statement, depending on context.

    "In order to enter Taiwan, COVID vaccination is required.
    Anything that is required to enter Taiwan should be prioritized as we plan for our upcoming vacation."

    Now the first sentence is better seen as "COVID vaccination -> Required for entering Taiwan" (or, in plain english, COVID vaccination is something that's required to enter Taiwan), which allows us to connect it to the next sentence to reach the conclusion that the COVID vaccination should be prioritized as we plan for our upcoming vacation.

    Someone approaching things mechanically might say "How could COVID vaccination be a sufficient condition? We were told it was necessary! I don't see how you can put it on the left side of the arrow." How would you answer that question?

  • xuzuqiaoxuzuqiao Core Member
    91 karma

    Wow! I just finished my daily study session and came back to check if there have been additional responses to my post, and voilà, a long, juicy explanation courtesy of @KevinLuminateLSAT is waiting for me.

    I will need to take some time tomorrow to fully digest the details and implications of the subjects discussed in your post. In particular, I can clearly see that my singular focus on translating Sufficient Assumption arguments into simple sets of conditional statements overlooks the nuance of grammar and wording.

    And here I was thinking the LSAC had made a mistake, rather than questioning whether my logic translations were overly reductive.

    Thank you for this (your post yesterday on weakening arguments by showing inconsistency was illuminating as well!). After going through the first half, you've helped me realize some critical nuances in simple statements - I had never before considered that "the only" could mean a bi-conditional depending on whether it points to singular or plural subjects. I had hoped to develop a rather ruthless, wholly mechanical approach to SA questions to cut down on time, but ignoring context has also led to many frustrating hours for me (like for this Q!). Your post has been quite enlightening.

  • u______uu______u Alum Member
    edited September 2022 233 karma

    Thank you for the detailed response @KevinLuminateLSAT. If you could further spare some time to answer a couple more questions, I'd be very grateful.

    1) Unless directly specified, shouldn't we always assume that a particular claim about a group doesn't apply to every single member in it? I'm fairly certain that that's a flaw seen on the test. For example, in the example you've provided, "Humans are cruel. Thus, Paxton is cruel," wouldn't it be incorrect to conclude that unless we were explicitly told that cruelty is a trait of every human? Therefore, whenever we see an unspecified plural subject, shouldn't we treat it as meaning the group "in general?"

    2) I'm not sure I quite follow what you're saying about the bi-conditionals. If we apply what you said to the stimulus, I believe we'd get "pizzerias-->routinely record etc." So, if we link everything up, it would be:

    Pizzeria-->Routinely record-->Utilize direct-mail marketing more effectively

    Pizzerias utilize direct-mail marketing more effectively
    And it's because everything links up cleaner this way that you suggest that this would clear OP's confusion right?

    3) Regarding your example about Taiwan, I assume that it's because the vaccination itself is a requirement to enter Taiwan. Therefore, you can transform the first sentence to be COVID vaccination-->Requirement to enter Taiwan because the vaccination functions both as a sufficient item to conclude requirement for entry and also as a necessary for entry in Taiwan. Due to your earlier comments about bi-conditionals concerning "is," I think we're looking at specifically the "COVID vaccination is required" of the first sentence, which should work out to COVID vaccination <--> Requirement for entry. However, what I'm not understanding is, that given how it's currently written, don't the sentences already flow to mean "the COVID vaccination should be prioritized?" The umbrella of "anything that is required to enter Taiwan" would include the "COVID vaccination" since we already know that the vaccination is necessary for entry. Therefore, just adding in the vaccination for "anything that's required" would allow you to draw that conclusion.

  • KevinLuminateLSATKevinLuminateLSAT Alum Member
    983 karma

    @u______u said:

    Thank you for the detailed response @KevinLuminateLSAT. If you could further spare some time to answer a couple more questions, I'd be very grateful.

    1) Unless directly specified, shouldn't we always assume that a particular claim about a group doesn't apply to every single member in it? I'm fairly certain that that's a flaw seen on the test. For example, in the example you've provided, "Humans are cruel. Thus, Paxton is cruel," wouldn't it be incorrect to conclude that unless we were explicitly told that cruelty is a trait of every human? Therefore, whenever we see an unspecified plural subject, shouldn't we treat it as meaning the group "in general?"

    Is this a rule? I'm not saying you're wrong, but we can come up with some examples that seem to also refer to every single member.

    "Spelling bee winners are excellent at memorization." Is this saying every spelling bee winner is good at memorization? Or is it just referring to the group of spelling bee winners generally and allows for some exceptions?

    "Green vegetables have lots of fiber." Is this saying that every green vegetable has a lot of fiber, or just generally they have lots of fiber but there could be exceptions?

    "Humans need water to survive." This means every human needs water to survive right? Is this because the word "need" would only make sense if applied to every single human rather than human generally but allowing for exceptions?

    "Bullies should be avoided." Is this saying every bully should be avoided or is it referring just generally to bullies and that some may not be ones that are to be avoided?

    My honest answer is that I think this depends on the concepts involved as well as the context provided by the other statements. That may be wrong, but I hesitate about using a rule. In practice I think I find myself adding an implicit "all" to many plural subjects on the LSAT, but not always.

    2) I'm not sure I quite follow what you're saying about the bi-conditionals. If we apply what you said to the stimulus, I believe we'd get "pizzerias-->routinely record etc." So, if we link everything up, it would be:

    Pizzeria-->Routinely record-->Utilize direct-mail marketing more effectively

    Pizzerias utilize direct-mail marketing more effectively
    And it's because everything links up cleaner this way that you suggest that this would clear OP's confusion right?

    Yes, that's right. That strikes me as what the LSAT intended, rather than merely reading the conclusion as about "some pizzerias".

    3) Regarding your example about Taiwan, I assume that it's because the vaccination itself is a requirement to enter Taiwan. Therefore, you can transform the first sentence to be COVID vaccination-->Requirement to enter Taiwan because the vaccination functions both as a sufficient item to conclude requirement for entry and also as a necessary for entry in Taiwan. Due to your earlier comments about bi-conditionals concerning "is," I think we're looking at specifically the "COVID vaccination is required" of the first sentence, which should work out to COVID vaccination <--> Requirement for entry. However, what I'm not understanding is, that given how it's currently written, don't the sentences already flow to mean "the COVID vaccination should be prioritized?" The umbrella of "anything that is required to enter Taiwan" would include the "COVID vaccination" since we already know that the vaccination is necessary for entry. Therefore, just adding in the vaccination for "anything that's required" would allow you to draw that conclusion.

    I don't think there would be biconditional created by this statement - I did not mean to suggest that this example was similar to the pizza examples above.

    The statement would mean If enter taiwan -> Covid vaccination.

    And, if we're talking about the quality of being required for entry into Taiwan, then you could also say If COVID vaccination -> Is something that is required for entry into Taiwan.

    But COVID vaccination <---> Requirement for entry into Taiwan would not be inferrable, because there could be other requirements for entry besides COVID vaccination.

    This example was to show that the most basic conditional statement can be framed in another way that's also true, not that it creates a biconditional.

    Also, when you say "don't the sentences already flow to mean..." - that's because you're reading the sentences accurately without necessarily resorting to a diagram-type approach. I was trying to show that one who did use a mechanical approach might be confused by the very thing that you're grasping naturally from the flow of the sentences themselves.

  • u______uu______u Alum Member
    233 karma

    @KevinLuminateLSAT thank you again for your help. It seems I am still lacking in many aspects. This has been very edifying.

  • edited September 2022 175 karma

    @dzxu88 @u______u @KevinLuminateLSAT

    Great diagnosis by Kevin and great discussion thread. I have a marking in my notes on this exact question that reads "Interesting question re logical indicators...employing the sufficiency indicator blindly here actually runs you into confusion".

    The way I mapped the first statement of the stim was also as a biconditional. Test this by simply omitting the words "the only". You are left with "Pizzerias are restaurants that routinely record the names, addresses, and menu selections of their customers". We can safely map P ---> RR from that. So we have to ask ourselves just exactly what function "the only" is serving here. The answer it seems is that it's playing an exclusionary role. It's saying that no other type of restaurant routinely records names, addresses and menu selections. So putting them together you get P <---> RR which allows for E to work perfectly.

    Consider a more stock standard biconditional. "I walk my dog if and only if it's sunny". You can omit the "if" and map it as WD ---> S, but you lose some of the meaning of that statement if that's all you take away from it. That's definitely not to say that "the only" always indicates an biconditional relationship, merely that in specific contexts it can. "The only day I walk my dog is on Wednesday", for instance, is not a biconditional unless you actually focus on a slightly different aspect of the statement as Kevin points out. Something like Wednesday <---> Day that I can walk my dog. Just writing now, I believe this omission test may act as somewhat of a rule. If you drop "the only" from the statement in question and the conditionality doesn't change then it's probably not a biconditional. E.g. dropping "the only" in "Hard work is the only way to be successful" doesn't suddenly mean hard work is sufficient for success. Interested to hear your guys' thoughts on this.

    I think this question also plays into a forgotten or ignored aspect of another type of conditional statement. Consider "Only A are B" type of conditionals. E.g. "Only humans are capable of happiness". By mapping it constantly as "Capable of Happiness ---> Human", one may develop the tendency to ignore the contrapositive and brush over the fact that we are simultaneously told that no other thing can be capable of happiness.

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