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Thanks for posting Sgt. Brody! This question is pretty tricky!

First, you're right that there is some generalizing going on here, and that's problematic. But remember that arguments can (and often do) have more than one flaw. (C) incorrectly characterizes the generalization that's being made here. Let's break out the core before we go any further.

• PREMISE:
  Anthros say IF humans had not evolved ability to cope --> humans would not have survived.
  Austra-species evolved an ability to cope, but did not survive.
  CONCLUSION:
  Anthros are wrong.

Screwing up the Conditional
Notice that the anthropologists claim is a conditional claim. IF humans had not evolved the ability to cope with diverse natural environments, then we would not have survived prehistoric times. Conditional language always brings in the possibility of dealing with necessity/sufficiency. Ignoring for the moment the potential flaw with shifting from humans to other species, we have a rule and its contrapositive:

• If NO ability to cope --> NO survive
  If survive --> ability to cope
  

The author brings up a case of a species that HAD the ability to cope and did NOT survive, and claims that this breaks the above rule. But it doesn't! The rule only tells us what should happen when there is NOT an ability to cope, or when there IS survival. The only way for the author to think this broke the rule would be if the author screwed up the direction of the if/then statement.

If the author had thought the rule was "if ability to cope --> survive", then the Austra-species would break the rule! But alas, that's not the rule - that's an illegal reversal of the conditional. 'Screwing up the direction of a conditional statement' is also known as 'mixing up sufficient and necessary'. The if-clause of a conditional is a sufficient clause, as it is the thing that guarantees the result; similarly, the then-clause is the necessary clause, as it is required to be true once the if-trigger is met. Exchanging the if-clause for the then-clause can therefore be described as confusing the necessary for the sufficient (or vice versa).

This is why (A) is a flaw of the argument. Even if you fixed the odd generalization leap that's being made, this would still be extremely problematic. The part that should have been a red flag to you was the fact that anthropologists' claim was a conditional statement, and conditionals are often described in terms of their necessary and sufficient elements.

Generalizations
Now, I said before that there is absolutely a generalization from humans to other species going on in the argument, and that's a flaw as well - so why isn't (C) right? (C) describes the generalization that's going on in the argument incorrectly. If the author believed that all related species with the same characteristic (ability to cope) must have survived, that doesn't support a conclusion that the anthropologists are wrong about the rule about humans. If the author assumed this, though, his assumption would directly contradict the premise-fact that the Austra-species had the characteristic and did not survive. Also, notice that the generalization described here does not stem from the anthropologists if/then statement (which is what the conclusion is all about), but rather stems from the mere fact that humans had the ability to cope and survived. Also note that (C) requires that the author to assume those other species must have survived exactly the same conditions as we did. That's incredibly specific, and we don't need to author to assume that for the argument to work.

If (C) had said "generalizes, from the fact that one species required a certain characteristic in order to survive, that a related species must have had that same characteristic in order to survive", that would have more accurately represented the one part of the generalization. If it had said "generalizes, from the fact that one species required a certain characteristic to survive, that a related species that had that characteristic would have therefore survived", then that could have encompassed both the generalization flaw as well as the necessary/sufficient flaw.

Remember, it's not enough for an answer choice to just use the word "generalization" - it must then describe the existing generalization correctly. Also, anytime conditionals are in play, there's a possibility of messing us the direction of the conditional, and thereby committing a necessary vs sufficient error.

Thoughts?









All of you are welcome to leave questions here, as I check this thread regularly. Feel free to ask questions about the LSAT in general, work out specific LSAT questions, ask for study advice, or ask questions about our books. Or anything else LSAT!

Christine (MLSAT) wrote:Thanks for posting Sgt. Brody! This question is pretty tricky!

First, you're right that there is some generalizing going on here, and that's problematic. But remember that arguments can (and often do) have more than one flaw. (C) incorrectly characterizes the generalization that's being made here. Let's break out the core before we go any further.

• PREMISE:
  Anthros say IF humans had not evolved ability to cope --> humans would not have survived.
  Austra-species evolved an ability to cope, but did not survive.
  CONCLUSION:
  Anthros are wrong.

Screwing up the Conditional
Notice that the anthropologists claim is a conditional claim. IF humans had not evolved the ability to cope with diverse natural environments, then we would not have survived prehistoric times. Conditional language always brings in the possibility of dealing with necessity/sufficiency. Ignoring for the moment the potential flaw with shifting from humans to other species, we have a rule and its contrapositive:

• If NO ability to cope --> NO survive
  If survive --> ability to cope
  

The author brings up a case of a species that HAD the ability to cope and did NOT survive, and claims that this breaks the above rule. But it doesn't! The rule only tells us what should happen when there is NOT an ability to cope, or when there IS survival. The only way for the author to think this broke the rule would be if the author screwed up the direction of the if/then statement.

If the author had thought the rule was "if ability to cope --> survive", then the Austra-species would break the rule! But alas, that's not the rule - that's an illegal reversal of the conditional. 'Screwing up the direction of a conditional statement' is also known as 'mixing up sufficient and necessary'. The if-clause of a conditional is a sufficient clause, as it is the thing that guarantees the result; similarly, the then-clause is the necessary clause, as it is required to be true once the if-trigger is met. Exchanging the if-clause for the then-clause can therefore be described as confusing the necessary for the sufficient (or vice versa).

This is why (A) is a flaw of the argument. Even if you fixed the odd generalization leap that's being made, this would still be extremely problematic. The part that should have been a red flag to you was the fact that anthropologists' claim was a conditional statement, and conditionals are often described in terms of their necessary and sufficient elements.

Generalizations
Now, I said before that there is absolutely a generalization from humans to other species going on in the argument, and that's a flaw as well - so why isn't (C) right? (C) describes the generalization that's going on in the argument incorrectly. If the author believed that all related species with the same characteristic (ability to cope) must have survived, that doesn't support a conclusion that the anthropologists are wrong about the rule about humans. If the author assumed this, though, his assumption would directly contradict the premise-fact that the Austra-species had the characteristic and did not survive. Also, notice that the generalization described here does not stem from the anthropologists if/then statement (which is what the conclusion is all about), but rather stems from the mere fact that humans had the ability to cope and survived. Also note that (C) requires that the author to assume those other species must have survived exactly the same conditions as we did. That's incredibly specific, and we don't need to author to assume that for the argument to work.

If (C) had said "generalizes, from the fact that one species required a certain characteristic in order to survive, that a related species must have had that same characteristic in order to survive", that would have more accurately represented the one part of the generalization. If it had said "generalizes, from the fact that one species required a certain characteristic to survive, that a related species that had that characteristic would have therefore survived", then that could have encompassed both the generalization flaw as well as the necessary/sufficient flaw.

Remember, it's not enough for an answer choice to just use the word "generalization" - it must then describe the existing generalization correctly. Also, anytime conditionals are in play, there's a possibility of messing us the direction of the conditional, and thereby committing a necessary vs sufficient error.

Thoughts?









All of you are welcome to leave questions here, as I check this thread regularly. Feel free to ask questions about the LSAT in general, work out specific LSAT questions, ask for study advice, or ask questions about our books. Or anything else LSAT!

Thank you so much Christine for such a detailed response!, I learnt a new thing today!, I never knew that conditional statements usually brings out necessary/sufficient element. So, when we run into a conditonal statment used in a identify the flaw q, would u reccomend keeping an eye out for the sufficient/neccessary factor in the answer choices? and just to follow up, is answer choice B also ruled out for the reason as answer choice C, because it used "MUST have had the same characteristic", and can you also hep me why A is chosen over E, as on the surface E also seems to have the necessary/sufficient element.

Christine, I am noticing a few things that bother me as I drill more necessary assumption questions - this is most likely signaling a lack of understanding and I would like to know what you think about it. I'll bring up a few examples: PT16-S3-Q12 (the retina scanner), PT15-S3-Q3 (the stationary enveloped question), and PT25-S4-Q9 (Federici Art Museum). I'll start with the retina scanner question...

PT16-S3-Q12

No two eyes have identical patterns of blood vessels in the retina
→
A retina scanner can therefore be used to successfully determine for any person whether it has scanned that retina before

"Any person" is clearly a big hint here, and this is what would lead to (A) as the correct answer. (A) talks about how diseases of the eye don't alter the blood vessels so much so that it makes the pattern unrecognizable. That seems necessary because, after all, if this wasn't the case then we could argue that the retina scanner could't be used successfully on people with eye diseases! That makes sense. The problem though is that don't we additionally have to assume that there is at least one person with an eye disease for (A) to work correctly? If there is nobody with an eye disease (a stretch, I know, but still possible) then (A) could still be negated while having the argument stand strong. Because no information is given on people with eye diseases in the stimulus, couldn't we just as easily assume that there is no one with an eye disease as we can that there are some people with an eye disease?

PT15-S3-Q3

Similarly, in the envelope question we get something like this:

When the envelopes have windows, these windows are also made from recycled material
→
The envelopes are completely recyclable

Now the gap here is obvious. Who is to say that being made of "recycled material" means it is "recyclable." However, let's look at the negation of (C): "The envelope windows are not recyclable." The stimulus just says "when the envelopes have windows," failing to guarantee that the envelopes actually have windows. Thus, couldn't the argument stand strong even with (C) negated? After all, we could just as easily assume that the envelopes don't have windows as the envelopes do have windows.

PT25-S4-Q9

Here is another, somewhat different problem.

The curator has long maintained that some paintings are of an inferior quality and add nothing to overall quality of the museum's collection
→
The board's action of selling some works will not detract from the quality of the museum's collection

We get the correct answer (B) here quite easily: "All of the paintings that the board sells will be among those that the curator recommends selling." Yet this "all" is really troubling. The curator recommends selling "several unsuccessful immature works by Renoir and Cezanne." These works "add nothing." Okay. But it doesn't have to be true that only these works "add nothing." What if other works, say works done by an immature Picasso when he was 12, also "add nothing." These Picassos were not recommended by the curator to sell but, since they also "add nothing," couldn't we sell them without "detracting from the quality of the museum's collection?" It seems that we could. Thus, I don't know if I fully believe that the negation of (B) would do that much to the argument.


As you can see, there is something I am missing here. I think it is either a shoddy understanding of the negation test or perhaps a lack of understanding in outside inferences/assumptions. Any thoughts?

Sgt Brody. wrote: Thank you so much Christine for such a detailed response!, I learnt a new thing today!, I never knew that conditional statements usually brings out necessary/sufficient element. So, when we run into a conditonal statment used in a identify the flaw q, would u reccomend keeping an eye out for the sufficient/neccessary factor in the answer choices? and just to follow up, is answer choice B also ruled out for the reason as answer choice C, because it used "MUST have had the same characteristic", and can you also hep me why A is chosen over E, as on the surface E also seems to have the necessary/sufficient element.

I'm generally wary of having blanket rules to things, but you should always *notice* conditional language when it appears. The fact that screwing up the conditional is easy to do should just be a danger light in your mind. If the *author* screws up the conditional, then their flaw might be described in necessary/sufficient terms. But it might also be described in other ways too! It's important to remember why conditionals can be described in this way.

• If I do dancing, then I will sleep late.

The dancing is sufficient to guarantee sleeping late. The sleeping late must necessarily follow dancing!

(E) has a few problems. You're right, it looks at a glance as if it focuses on necessary/sufficient, but a major problem is that it introduces the notion of causation. Causation is a whole different can of worms. That alone is a giant red flag. But let's parse the initial part of the sentence "even if a condition caused a result to occur in one case" - is that what our premise is talking about? What condition "caused" what result? The only way to match that up would be to say that "evolving an ability to cope" caused humans to survive. But the premise does not actually say that. The premise says that if we had not had the ability to cope, we would not have survived. In other words, the premise only gives us a conditional relationship, and doesn't tell us that there is a causal relationship. We cannot assume causal relationships from conditional relationships! This is the most important and obvious reason why (E) is wrong.

But, even if you mistakenly thought this phrase matched up to the premise, we still have a problem: now that we've shoehorned our premise into the answer choice, the answer choice basically says the argument fails to consider the possibility that "even if evolving an ability to cope caused humans to survive, evolving an ability to cope was not necessary for the survival of Autra-species." But the author isn't claiming that the ability to cope was NECESSARY for the Austra-species. He was mistakenly assuming the ability to cope ought to have been sufficient to ensure survival.

So, (E) introduces a causation element that is not present in the argument, and it also undermines the idea that the ability to cope would be necessary to survival, while the author is assumption that the ability to cope should be *sufficient*.

(B) is actually wrong for a slightly different reason than (C). The assumption in (B) is really just a premise booster. Fitting in the specifics of the argument, it says that the argument assumes that if humans had the ability to cope, and that that happened to allow us to survive, that there must be at least one related species (Austra-species) that has the same characteristic (ability to cope). But we already know from the premises that the Austra-species did have the ability to cope! So this assumption is just giving us a premise we already know - it doesn't point out a flaw!

Does that help?

WaltGrace83 wrote:Christine, I am noticing a few things that bother me as I drill more necessary assumption questions - this is most likely signaling a lack of understanding and I would like to know what you think about it. I'll bring up a few examples: PT16-S3-Q12 (the retina scanner), PT15-S3-Q3 (the stationary enveloped question), and PT25-S4-Q9 (Federici Art Museum). I'll start with the retina scanner question...

You know I love to see you grappling this deeply with all of these ideas! Let's dig in:

WaltGrace83 wrote: PT16-S3-Q12
No two eyes have identical patterns of blood vessels in the retina
→
A retina scanner can therefore be used to successfully determine for any person whether it has scanned that retina before

"Any person" is clearly a big hint here, and this is what would lead to (A) as the correct answer. (A) talks about how diseases of the eye don't alter the blood vessels so much so that it makes the pattern unrecognizable. That seems necessary because, after all, if this wasn't the case then we could argue that the retina scanner could't be used successfully on people with eye diseases! That makes sense. The problem though is that don't we additionally have to assume that there is at least one person with an eye disease for (A) to work correctly? If there is nobody with an eye disease (a stretch, I know, but still possible) then (A) could still be negated while having the argument stand strong. Because no information is given on people with eye diseases in the stimulus, couldn't we just as easily assume that there is no one with an eye disease as we can that there are some people with an eye disease?

Interesting question! So, when you negate (A), you get a statement that "diseases of the eye do alter the pattern of blood vessels..." I would argue that that statement is telling you that alternation is happening somewhere, with someone. If it said "diseases of the eye, if they ever occur, would alter the pattern of blood vessels..." then that gives you what abstract notions of eye disease theoretically would do if they ever came to pass. But "do alter" indicates that it is occurring.

Here's another way to think about it: The big, blanket assumption the argument is making is that nothing changes the blood vessel patterns enough to make them unrecognizable. That includes diseases of the eye - we have to assume diseases of the eye aren't doing that (what (A) says), but that could be either because they *never* do that when people have them, or because they don't exist. Either one would work. If no diseases of the eye occur, then they certainly cannot alter the pattern of blood vessels!

Take a look at this argument:

• PREMISE:The train left the station on time.
  CONCLUSION:The train will arrive at its destination on time.

We're assuming that nothing gets in the way, and a lot of things fall into that umbrella. One thing we're assuming is that aliens don't abduct the trains. Whether or not aliens exist is not relevant - either they don't exist, in which case they clearly aren't abducting trains, or they do exist but don't abduct trains. In either case, we are assuming that aliens don't abduct trains.

WaltGrace83 wrote: PT15-S3-Q3

Similarly, in the envelope question we get something like this:

When the envelopes have windows, these windows are also made from recycled material
→
The envelopes are completely recyclable

Now the gap here is obvious. Who is to say that being made of "recycled material" means it is "recyclable." However, let's look at the negation of (C): "The envelope windows are not recyclable." The stimulus just says "when the envelopes have windows," failing to guarantee that the envelopes actually have windows. Thus, couldn't the argument stand strong even with (C) negated? After all, we could just as easily assume that the envelopes don't have windows as the envelopes do have windows.

Yes, this is a similar issue. This is getting into very fine tuned use of language at this point. I want to stress to you that the distinction in both the retina question and this one are much too nuanced to be likely to be tested explicitly. It's good you are grappling with this, to deepen you own understanding of these things, but you should also be aware that many people get through these questions without understanding these distinctions.

Very similar to the issue above, if the stimulus had said "If the envelopes were to have windows, those windows would have to be made from recycled material", that would very clearly introduce an abstract rule that may or may not ever be triggered in reality. However, the phrase "when X occurs" does imply that X sometimes occurs, even if we don't know exactly when. Furthermore, the result of the conditional is not "these windows would have to be made" but rather "these windows are made", which also implies it occurs. "When I go to the gym, I take my yoga mat" definitely communicates that there are times when I go to the gym! We just don't know when they are/were.

This difference might be thought of as the difference between statements of habitual fact and hypotheticals/future conditionals - all are written in conditional language, but one exists in the now and the other only might exist, if it is triggered. Once again, I have to stress that I think it's extraordinarily unlikely they would ever have a distinction between two answers hinge on such a nuanced issue. However, it's a useful thing to understand about the English language, verb tenses, and essential reading comprehension.

WaltGrace83 wrote: PT25-S4-Q9

Here is another, somewhat different problem.

The curator has long maintained that some paintings are of an inferior quality and add nothing to overall quality of the museum's collection
→
The board's action of selling some works will not detract from the quality of the museum's collection

We get the correct answer (B) here quite easily: "All of the paintings that the board sells will be among those that the curator recommends selling." Yet this "all" is really troubling. The curator recommends selling "several unsuccessful immature works by Renoir and Cezanne." These works "add nothing." Okay. But it doesn't have to be true that only these works "add nothing." What if other works, say works done by an immature Picasso when he was 12, also "add nothing." These Picassos were not recommended by the curator to sell but, since they also "add nothing," couldn't we sell them without "detracting from the quality of the museum's collection?" It seems that we could. Thus, I don't know if I fully believe that the negation of (B) would do that much to the argument.

Ah, now THIS is an issue that students struggle with frequently. So, when you negate the necessary assumption, it does not have to make the conclusion false. Here's something else I posted recently on the subject

Christine (MLSAT) wrote:The negation test is unfortunately very often misunderstood. To "destroy an argument", the negation of a necessary assumption does not have to make the conclusion categorically false, it merely has to make it unsupported. In other words, the 'destruction' is not so much the conclusion as it is the link between the premise and the conclusion.

Take a crazy simple example:
PREMISE: All boys like sports.
CONCLUSION: Andy likes sports.

This argument is clearly assuming that Andy is a boy. That's necessary to the argument. If we negate it, we get "Andy is not a boy". Now, if Andy is a girl, it is still possible that she likes sports, right? If Andy is a girl, we have NO IDEA about her sports preference, and there would be zero connection between the premise and the conclusion. The conclusion would not be definitively false, but it would be wholly unsupported.

While it is possible to negate the assumption and still make the conclusion true, the premise no longer provides support for the conclusion in this universe. It's not about destroying the conclusion categorically, it's about destroying the link between the premise and the conclusion. That's what "destroying the argument" is really all about.

So, perhaps we can sell other useless pieces of art and still not harm the collection, but the curator's recommendations are not supporting that conclusion anymore!

WaltGrace83 wrote:
As you can see, there is something I am missing here. I think it is either a shoddy understanding of the negation test or perhaps a lack of understanding in outside inferences/assumptions. Any thoughts?

So, two things are happening here: in the first two questions you are grappling with the very fine details of language use (that will likely never be explicitly tested), and in the third question you are coming face to face with the true meaning and nature of the negation test!

Does that help? Please let me know if you have additional thoughts or questions about any of this!

Christine (MLSAT) wrote:
So, two things are happening here: in the first two questions you are grappling with the very fine details of language use (that will likely never be explicitly tested), and in the third question you are coming face to face with the true meaning and nature of the negation test!

Does that help? Please let me know if you have additional thoughts or questions about any of this!

Thanks a lot! It is indeed the case that I did not understand the negation test fully until you made that post about it a few weeks ago. Since then, I have been trying to implement it, write about it, and more deeply understand it. I guess there are just some instances that I am still learning about and I think part of my apprehension on an answer choice like this (this also happened on 36.3.14, the "machine question") is the wording..."all," "most," etc. always makes me super tense on an NA question - like I am missing something if I feel like it is the correct answer.

WaltGrace83 wrote:

Christine (MLSAT) wrote:
So, two things are happening here: in the first two questions you are grappling with the very fine details of language use (that will likely never be explicitly tested), and in the third question you are coming face to face with the true meaning and nature of the negation test!

Does that help? Please let me know if you have additional thoughts or questions about any of this!

Thanks a lot! It is indeed the case that I did not understand the negation test fully until you made that post about it a few weeks ago. Since then, I have been trying to implement it, write about it, and more deeply understand it. I guess there are just some instances that I am still learning about and I think part of my apprehension on an answer choice like this (this also happened on 36.3.14, the "machine question") is the wording..."all," "most," etc. always makes me super tense on an NA question - like I am missing something if I feel like it is the correct answer.

Skepticism about strong language in Necessary Assumption answer choices is a good instinct. However, as you're finding, it's not a guaranteed elimination tactic! But it should always be a red flag to double check that you really *require* that strength of language.

The best place to start on that double checking is in the conclusion's strength of language. For instance, if the conclusion makes a statement with 'all', 'every', 'never', etc, then it may well be that you need similarly strong language in the assumption to back it up. In PT36-S3-Q14, the conclusion uses language of "in general" and "no better than", and the "most" language of the correct answer is required to support the "in general".

In the art question, the strength is a little more hidden. The conclusion doesn't use obvious language strength indicators, but it is making a conclusion about a number of paintings (the ones to sell). The issue here is that to make the conclusion about the *group* of paintings, we have to connect those paintings to the support provided in the premise - and we have to connect every single one of the paintings. So, the strength of language required in the assumption is not driven directly by strength of language in the conclusion, but rather by the fact that author is concluding something about ALL the members of a group of things.

So, don't kill your skepticism on strong language! Just allow that skepticism to trigger a judicious assessment of whether strong language is, in fact, required.









All of you are welcome to leave questions here, as I check this thread regularly. Feel free to ask questions about the LSAT in general, work out specific LSAT questions, ask for study advice, or ask questions about our books. Or anything else LSAT!

Thanks a lot! If you have some time, I have been trying to figure this question out, PT14 S4 Q9 "Since anyone who supports the new tax plan..." Any thoughts? I am trying to pinpoint how this is different from a sufficient assumption as I think that this distinction is the root of my confusion. After reading the argument and realizing this is heavily conditional, here is my thought process. Everything in purple are my SA-related thoughts and everything in italics is my real-time thought process.

EDIT: so we are clear, I do know this is technically a flaw question.

Step #1: Write out the conditionals.

Supports → ~Elected
Understands Economics → ~Support
======
Elected → Understands Economics

Step #2: Match up the conditionals

Elected → ~Support
Understands Economics → ~Support
======
Elected → Understands Economics

• I took the contrapositive of Premise 1 so that I would have a matching sufficient condition between Premise 1 and the conclusion.

• • Now correct me if I am wrong, but isn't it incredibly rare that a sufficient assumption question has two premises with the same exact necessary condition? This definitely tripped me up when I saw it.

• After this, I have to find out how to link up the premises to make it look like the conclusion - aka, I have to figure out what assumption is being made by the conclusion. Because the two premises are so weird, having the same necessary conditional and all, the only way to do this would be like the following...

Elected → ~Support → Understands Economics
======
Elected → Understands Economics

• The argument is assuming that anyone who (~Support) must (Understand Economics). We understand this to be so because there is no other way to link the two premises up to match the conclusion.

Step #3: Answer the Question.

• Now this one trips me up because it is asking what is being ignored, not assumed. Because it is asking about ignorance, we take the assumption and say that it could be the case that it isn't true. In other words, it could be the case that you can (~Support) but still (~Understand Economics). We know this because this is the goal of all flaw questions - we say that, while the premises are true, they don't necessarily lead to the conclusion. With this in mind, (D) is the correct answer.

However, if this were a sufficient assumption question, we would actually state in some way the opposite! In other words, we would say that "the author is assuming that (~Support → ~Understand Economics)

For the purposes of review, let's look at the wrong answers.

Elected → ~Support
Understands Economics → ~Support
======
Elected → Understands Economics

• (A) (Understand Economics → ~Support) This is actually stated by Premise 2. This is merely a premise booster.
  
  (B) (Elected → ~Understands Economics) This reverses the conclusion's necessary condition.
  
  (C) (Elected → Support) This would be a bad reversal of Premise 1's necessary condition. This is no good.
  
  (E) (~Elected → ~Understand Economics) This is a mistaken reversal of the conclusion.

Yet as I look at these reasons for elimination, they seem awfully similar to sufficient assumption eliminations. This also confuses me. What am I missing here? Also, is this an uncommon question stem because I personally haven't seen it that I can remember.

WaltGrace1983, you continue to make really interesting analyses! There's a lot going on here that's worth discussing!

First, there's a fun thing to realize about flaw questions. Flaw questions can be phrased in two, somewhat opposite ways:

The argument is flawed because it assumes things.
The argument is flawed because it ignores the possibility of things.

The first one is fairly straightforward, in that the bracketed part is a necessary assumption of the argument. The second one is completely different - it wants the thing ignored, that which, if it were true would royally screw up the argument. The idea of royally screwing up the argument should sound an awful lot like what happens when we negate a necessary assumption! And that's exactly what's happening: the bracketed part of the second phrasing of a flaw should give you a negated necessary assumption.

Take the super simple argument:

• PREMISE: All boys like sports
  CONCLUSION: Andy likes sports

The argument is flawed because it assumes that Andy is a boy.
The argument is flawed because it ignores the possibility that Andy is NOT a boy.

So, flaws and assumptions are inherently related, regardless of which syntax the flaw is in. However, the assumption that is related in this way is a necessary assumption, not necessarily a sufficient assumption. As a result, all the analysis on Sufficient Assumption is in the ballpark, but a little dangerous in its general usability.

So, you're totally right that it would be really unusual for a Sufficient Assumption question to give you two premise conditionals that had the same necessary condition. In fact, that's exactly what wrong with the argument. The thing you were tripped up by is the very thing that actually makes the argument flawed in the end, though we wouldn't know that for certain at first glance. I think the fact that you were approaching this as a sufficient assumption question was what got you a little turned around here. That weirdness should be a red flag that the argument is funky - which makes sense, because its flawed!!

Once you rewrite the conditionals in this way:

Elected → ~Support
Understands Economics → ~Support
======
Elected → Understands Economics

You might notice that if someone had illegally reversed the second conditional, the conclusion would make sense.

Elected → ~Support
~Support → Understands Economics
======
Elected → Understands Economics

That's essentially what you came up with in your next step, but it's critical to see that one would merely have to illegally flip the second conditional to make that mistake.

So, a totally valid answer to a plain old 'what's the flaw' question would be: The argument is flawed because it assumes that a condition necessary for a certain characteristic must also be sufficient for that characteristic. We could also say that the argument is flawed because it assumes that if one does not support the tax plan, they must understand economics.

But this question stem uses the alternate flaw syntax of "ignores the possibility". So, we want the answer to contain the negated assumption we've just identified. And this contains another level of stickiness: negating conditionals is weird. If we want to negate a rule "If X --> Y", I just need to show that it's possible to have the trigger X without having the result Y. Imagine if I said "All apples are red" - to call me a liar, you just need to show that it's possible for an apple to be not-red.

So, to negate the conditional "if ~support --> understand economics", then I need to show that it's possible for someone to not support the plan and also NOT understand economics! That possibility would break the conditional, showing the conditional to be not-a-rule.

So, (D) gives us the possibility that kills the conditional that the argument must be assuming to get to its conclusion!

Eliminations here are fairly confusing, but what you need to keep forefront in your mind is whether the existence of a person who meets the pair of criteria would do any damage to the necessary assumptions of the argument.

Thoughts?

Hi Christine,

I am having trouble with PT13, S4, Q16. I understand why C is the correct answer, but I could not see why D is incorrect. Could you please help? D seems to match the fallacy to me and I couldn't confidently eliminate it even though I ultimately chose C.

Thanks in advance for your help!

iiibbystar wrote:Hi Christine,

I am having trouble with PT13, S4, Q16. I understand why C is the correct answer, but I could not see why D is incorrect. Could you please help? D seems to match the fallacy to me and I couldn't confidently eliminate it even though I ultimately chose C.

Thanks in advance for your help!

Great question!

As you can probably see, what's going on here is a part-whole fallacy, but the difference between (C) and (D) highlights an aspect of part-whole that's often not well understood.

Part-whole fallacies come in a few essential flavors (with endless slight variations):
1) part = all parts
2) part = whole

For some examples, there's no useful difference between these two ideas. For instance, if every tile in the floor is red, then the entire tile floor is red. However, consider the ingredients in a dish: every ingredient being individually tasty does not necessarily mean that the dish as a whole entity will be tasty. As a result, the following are two fundamentally different types of flaws:

• 1) the cheese the chef uses in the lasagna is delicious, therefore every ingredient the chef uses in the lasagna must be delicious
  2) the cheese the chef uses in the lasagna is delicious, therefore the chef's lasagna must be delicious

In fact, a third common part-whole flaw flavor is a direct connection of those things:
3) all parts = whole

• every ingredient the chef uses in the lasagna is delicious, therefore the chef's lasagna must be delicious

In this question, the stimulus itself tells us directly that we are dealing with the fallacy of "each part = all parts (simultaneously)". The examples given in the stimulus and the correct answer are of people entering a tournament (each person individually could win, but they can't all win simultaneously) and people up for appointment to an opening on a committee (each person could be appointed, but they can't all be appointed simultaneously).

(D), however, discusses the probability that a coin will be heads on a flip (1/2), and then concludes that the probability of 5 heads occurring simultaneously is also 1/2. The improper leap is to a characteristic (1/2 probability) of the group as a whole. rather than a characteristic of each individual component occurring simultaneously. To match the example, this answer would have to say something like:

• Each coin has a 1/2 probability of flipping heads, but if you flip 5 coins they can't *each* have a 1/2 probability of flipping heads.

Which is not correct anyway - when you flip 5 coins, they each have a 1/2 probability of flipping heads, and those probabilities for each coin exists simultaneously!

Does that help a bit?

Christine (MLSAT) wrote:

iiibbystar wrote:Hi Christine,

I am having trouble with PT13, S4, Q16. I understand why C is the correct answer, but I could not see why D is incorrect. Could you please help? D seems to match the fallacy to me and I couldn't confidently eliminate it even though I ultimately chose C.

Thanks in advance for your help!

Great question!

As you can probably see, what's going on here is a part-whole fallacy, but the difference between (C) and (D) highlights an aspect of part-whole that's often not well understood.

Part-whole fallacies come in a few essential flavors (with endless slight variations):
1) part = all parts
2) part = whole

For some examples, there's no useful difference between these two ideas. For instance, if every tile in the floor is red, then the entire tile floor is red. However, consider the ingredients in a dish: every ingredient being individually tasty does not necessarily mean that the dish as a whole entity will be tasty. As a result, the following are two fundamentally different types of flaws:

• 1) the cheese the chef uses in the lasagna is delicious, therefore every ingredient the chef uses in the lasagna must be delicious
  2) the cheese the chef uses in the lasagna is delicious, therefore the chef's lasagna must be delicious

In fact, a third common part-whole flaw flavor is a direct connection of those things:
3) all parts = whole

• every ingredient the chef uses in the lasagna is delicious, therefore the chef's lasagna must be delicious

In this question, the stimulus itself tells us directly that we are dealing with the fallacy of "each part = all parts (simultaneously)". The examples given in the stimulus and the correct answer are of people entering a tournament (each person individually could win, but they can't all win simultaneously) and people up for appointment to an opening on a committee (each person could be appointed, but they can't all be appointed simultaneously).

(D), however, discusses the probability that a coin will be heads on a flip (1/2), and then concludes that the probability of 5 heads occurring simultaneously is also 1/2. The improper leap is to a characteristic (1/2 probability) of the group as a whole. rather than a characteristic of each individual component occurring simultaneously. To match the example, this answer would have to say something like:

• Each coin has a 1/2 probability of flipping heads, but if you flip 5 coins they can't *each* have a 1/2 probability of flipping heads.

Which is not correct anyway - when you flip 5 coins, they each have a 1/2 probability of flipping heads, and those probabilities for each coin exists simultaneously!

Does that help a bit?

Thank you, Christine! I think I got it now. The example you gave with the coins really help.

I don't know if I am overanalyzing 38.4.16 (the trust others/distrust/confidence problem) but can you shed some insight on this? I feel like this problem is very unlike most sufficient assumption questions and perhaps that is why I am having difficulty with it. Yet I don't know why I feel this way and maybe there is something about this problem that I am missing.

~Believe others distrust them → Confident
Conclusion: Tend to trust others → "Challenge"
Confident → "Challenge

This is put into formal logic in the exact order it is given in the stimulus. Perhaps it is a confusing problem because the premise is both the first sentence and the last sentence. Either way, the argument can be interpreted much more easily like the following...

~Believe others distrust them → Confident → "Challenge"
Conclusion: Tend to trust others → "Challenge"

Okay. So from here we see that both the premises and the conclusion share the same necessary condition. Perhaps here is where I am getting confused. When faced with this situation, should I always attach the sufficient condition of the conclusion to the sufficient condition of the first premise, thus getting Tend to trust others → ~Believe others distrust them? This would make sense considering it is the right answer however I guess the problem itself doesn't scare me but the theory behind the problem is what I want to learn.

Here is my takeaway and I would love some insight if I am wrong/right...

When the premise and the conclusion share a necessary condition, link the sufficient condition of the conclusion to the end of the sufficient condition of the premise. Another example of this would be PT32 S4 Q4 (the "visceral emotion" example).

V → H, therefore A → H
The correct answer is simply (A → V)

However, when the premise and the conclusion share one element or no elements in common, link the chain together in one big conditional chain!

SIDE NOTE: I think this was something that I alluded to a little while ago. It would rare, perhaps really rare (?) on the LSAT, for a chain of logic to be a big mess with a bunch of extraneous information rather than a simple A→B→C→D type chain. What I mean by that is, on a sufficient assumption question, it is very unlikely for the test writers to include information that isn't a part of the logic chain for a sufficient assumption question. I don't know if this will make sense when you read it but I hope you understand what I mean!




Anyway, if all my intuitions are correct, I am continually proven that the LSAT is something that can be done successfully even without the fullest knowledge of theory behind logic. I may get a lot of questions right in my studies so far but I swear I am finding new tidbits of the tiniest nuggets of information and understanding that I think will make me a much better LSAT taker. Sometimes I need to stop and think about just the basic elements of logic, such as what is outlined in my thinking in this post, in order to really GRASP all the techniques.

As always, thanks for any insight you may have!

WaltGrace83 wrote: Anyway, if all my intuitions are correct, I am continually proven that the LSAT is something that can be done successfully even without the fullest knowledge of theory behind logic. I may get a lot of questions right in my studies so far but I swear I am finding new tidbits of the tiniest nuggets of information and understanding that I think will make me a much better LSAT taker. Sometimes I need to stop and think about just the basic elements of logic, such as what is outlined in my thinking in this post, in order to really GRASP all the techniques.

First, I want to address this bolded comment: this is absolutely true. When we first begin to build our understanding, there comes a point where we start getting *attracted* to the correct patterns and modes without necessarily understanding every.tiny.element. At the beginning of your journey, most people have to throw their gut instincts out the window - they are dangerous, unreliable, and based on preconceptions about language we've held for years. But as you continue working on process and deepening your understand of logical patterns/structures, your instincts get shifted to a better and better orientation.

Look, when I took my LSAT I didn't miss a single question on it. And yet, in the years since then I have learned AN EPIC AMOUNT about both logic and the LSAT itself. Honestly, still to this day I am still learning from the LSAT, and fully believe that I will never stop. Yes, I am a shameless LSAT fangirl.

This information should do two things for you:

• 1) give you comfort that you can do quite well on the LSAT even if there are some things you are not yet a Jedi Master of

but

• 2) you (will always) still have a long way to go, young padawan - there is much you do not know.

To be clear: the WRONG LESSON to get out of the above, for anyone reading, would be that a deeper understanding of logic is useless to doing better on the LSAT. Absolutely perfect logical understanding and articulation is not strictly required for a good score, but the better your understanding/articulation is the more likely your are to do well (and do well consistently).



NOW - on to the meat and potatoes of your post:

WaltGrace83 wrote:I don't know if I am overanalyzing 38.4.16 (the trust others/distrust/confidence problem) but can you shed some insight on this? I feel like this problem is very unlike most sufficient assumption questions and perhaps that is why I am having difficulty with it. Yet I don't know why I feel this way and maybe there is something about this problem that I am missing.

It's actually not unique, but it's in a sub-category of SA questions.

If your standard SA question looks like this:

• PREMISE: Fact thing
  CONCLUSION: Prediction about the future

Then there's a high likelihood the sufficient assumption will follow the pattern of "If [premise], then [conclusion]", in this case "If fact thing occurs, then future prediction thing will always occur later."

When you have a conditional conclusion, this pattern is not very helpful. So, if your argument looked something like this:


Your conclusion is A-->E, and you want to make it work (Sufficient Assumption), so you have to figure out a way to get all the way from A to E. Imagine they are two islands, and you want to drive from one to the other - so you have to find bridges that get you there. There's not a direct bridge from Island A to Island E, so we have to work with smaller bridges. Fortunately, we have a lot of smaller bridges in play. Any bridge that starts at A and goes somewhere might be useful, and any bridge that ends up at E could be useful too.


You can see that the missing link here is C-->D. If we had that, we could drive all way from A to E, no problem! The end of your post is essentially describing doing exactly this.


What I'd like you to realize though is that the other situation, where there are two different sufficient clauses for the same necessary clause, is actually the exact same exercise. So, let's exchange A-->B for C-->D in the premises:

We still want to build that bridge from A to E, and any bridge that does part of the job will help:


Now, we're still looking for the missing link! The missing link just happens to be the very first link.


That missing link might also have ended up being the very last link! No real difference in our process! So, while everything you said about what you're doing is essentially correct, I think it's more useful to realize that all Sufficient Assumption questions with conditional conclusions can be broken down the same essential way regardless of where the missing link is.

WaltGrace83 wrote: SIDE NOTE: I think this was something that I alluded to a little while ago. It would rare, perhaps really rare (?) on the LSAT, for a chain of logic to be a big mess with a bunch of extraneous information rather than a simple A→B→C→D type chain. What I mean by that is, on a sufficient assumption question, it is very unlikely for the test writers to include information that isn't a part of the logic chain for a sufficient assumption question. I don't know if this will make sense when you read it but I hope you understand what I mean!

And finally this: it's certainly not common, but it does happen. There may be other examples of it, but the one that comes to mind is PT58-S1-Q25. It's a particularly brutal example of this kind of SA question, and it does have a piece of extraneous information - and that adds to the challenge. If you aren't saving PT58 for a full length PT, go ahead and check it out.

Because this is possible, it's best to focus on working forwards from the conclusion's sufficient, and backwards from the conclusion's necessary - that will keep you tracking for things that matter, and any extraneous information simply won't get picked up.

Let me know if this helps!

Sorry if I missed this but what "sub-category" of SA is this question in? What exactly did you mean by that?

Also, thanks a lot for the images too! They helped, definitely.

WaltGrace83 wrote:Sorry if I missed this but what "sub-category" of SA is this question in? What exactly did you mean by that?

Also, thanks a lot for the images too! They helped, definitely.

Oh, nothing formal - I really just meant "the subcategory of SA questions that have conditional conclusions". :p

Glad this helped!

Christine (MLSAT) wrote:

WaltGrace83 wrote:Sorry if I missed this but what "sub-category" of SA is this question in? What exactly did you mean by that?

Also, thanks a lot for the images too! They helped, definitely.

Oh, nothing formal - I really just meant "the subcategory of SA questions that have conditional conclusions". :p

Glad this helped!

Ah gotcha. Well I don't know what it is about this question that gave me a bit of trouble but thanks for the response!

I ordered the new RC strategy guide! It will be here by the end of the week and I am super excited. Do all the Manhattan geeks have something to do with its conception? Just wondering...

Anyway, I have a question for you in regards to strengthen/weaken questions. I'll use 28-3-9 as an example, the Market Research/Observational Research question. In my limited amount of time with strengtheners and weakeners, I have seen conclusions that look like this...

"Observational research yields information about consumer behavior that surveys alone cannot provide."

In other words, we are getting a comparison between two things. Now in order to strengthen or weaken this comparison, the answer choices would have to be comparative in nature, correct? When doing this question, I thought to myself, "well maybe way more people are willing to do observational research or maybe people lie on surveys..." These objections would be slightly off though, right? That is because I need to be thinking more along the lines of, "well maybe way more people are willing to do observational research than take surveys or maybe people lie on surveys yet cannot "lie" on observational research...". AKA, I should I be thinking in terms of a comparison in order to strengthen (or weaken) an argument about a comparison?

I feel like my hunch is correct as an answer choice like (B) would be pretty good otherwise. (B) speaks to a possible assumption that I thought of initially - the assumption that people tend to partake in observational research very often. However, I am also doubtful because this doesn't necessarily mean that market researchers are getting more information out of these participants. On the other hand though, we have no idea about how often people partake in surveys or even how often market researchers are able to pay the "consumer by the hour." I am thinking about these possible objections but I was hoping you would have some insight.

On another note, what is the deal with these strengtheners that ask to strengthen the "conclusion" or the "claim" or the "hypothesis." It seems like I should be attacking these a bit differently and the strategy guides gave a little bit of information on this but I would like a little more validation. When it talks about merely strengthening the conclusion, rather than the argument or reasoning etc., should I just work strengthening that conclusion alone and not exactly how it relates to any possible premises?

I feel like when a strengthen the argument or reasoning the question feels more like a necessary assumption. I typically try to see the disconnection between the premises and the conclusion and look for an answer that braces that disconnection.

Thanks as always. I think Manhattan ought to give you a bonus for all your work on TLS....or at least a muffin basket

WaltGrace83 wrote: Thanks as always. I think Manhattan ought to give you a bonus for all your work on TLS....or at least a muffin basket

Oooooh, maybe a cheese plate! I'll have to submit a request.

WaltGrace83 wrote: Anyway, I have a question for you in regards to strengthen/weaken questions. I'll use 28-3-9 as an example, the Market Research/Observational Research question. In my limited amount of time with strengtheners and weakeners, I have seen conclusions that look like this...

"Observational research yields information about consumer behavior that surveys alone cannot provide."

In other words, we are getting a comparison between two things. Now in order to strengthen or weaken this comparison, the answer choices would have to be comparative in nature, correct? When doing this question, I thought to myself, "well maybe way more people are willing to do observational research or maybe people lie on surveys..." These objections would be slightly off though, right? That is because I need to be thinking more along the lines of, "well maybe way more people are willing to do observational research than take surveys or maybe people lie on surveys yet cannot "lie" on observational research...". AKA, I should I be thinking in terms of a comparison in order to strengthen (or weaken) an argument about a comparison?

I feel like my hunch is correct as an answer choice like (B) would be pretty good otherwise. (B) speaks to a possible assumption that I thought of initially - the assumption that people tend to partake in observational research very often. However, I am also doubtful because this doesn't necessarily mean that market researchers are getting more information out of these participants. On the other hand though, we have no idea about how often people partake in surveys or even how often market researchers are able to pay the "consumer by the hour." I am thinking about these possible objections but I was hoping you would have some insight.

You are super spot on. If the conclusion were simply saying "Observational research is awesome and gives us tons of information!" then anything that bolstered observational research's awesomeness would help support such a claim. But the claim is more specific than that - it's saying that observational research gives information we can't get from surveys alone. It's absolutely comparative (or relational), and so yes, the answer really must deal with both observational research AND surveys!

Now, it's worth pointing out that the comparison is specific - it's not saying observational research is *better* than surveys - after all, it's still possible that surveys also provide information that observational research can't.

Your thoughts about (B) are similarly on target: people's willingness to participate in observational research doesn't really matter unless they are more willing to participate in it than they are in surveys. And even if they were more willing to, does that mean there's actually information that comes out of that? Plus, this only even applies when people are paid by the hour - how often is that? Does it happen for surveys too? How often? All these things we don't know show how little this answer choice actually tells us. It doesn't give us a real relationship between observational research and surveys that we can use, and it certainly doesn't give us one that produces specific information differences.

WaltGrace83 wrote: On another note, what is the deal with these strengtheners that ask to strengthen the "conclusion" or the "claim" or the "hypothesis." It seems like I should be attacking these a bit differently and the strategy guides gave a little bit of information on this but I would like a little more validation. When it talks about merely strengthening the conclusion, rather than the argument or reasoning etc., should I just work strengthening that conclusion alone and not exactly how it relates to any possible premises?

I feel like when a strengthen the argument or reasoning the question feels more like a necessary assumption. I typically try to see the disconnection between the premises and the conclusion and look for an answer that braces that disconnection.

The first thing I'll say is not to focus on the syntax of strengthening 'the conclusion' or 'the claim'. Those can absolutely be typical strengthen questions, where you should be focused on premise -----> conclusion and the gap. That being said, there are questions that literally have no premises. (This is covered, briefly, on p. 237 of the 3rd Ed. LR book, or p.258 of the 4th Ed. LR book)

This one I actually would not put in that category, though. So, I might break the core down as something like this:

• PREMISE: Observational research = watching consumers shopping; surveys = asking consumers questions
  CONCLUSION: Observational research gives info we can't get from surveys alone

Looking at it this way, we might already be zeroing in on the assumption that: watching people shop gives us more info than asking them questions That leads directly to (A), which targets not just a comparison, but an informational difference between the two data pools.

Does that make sense?

But you are continuing to improve and fine-tune your reasoning process. It's exciting to watch!

WaltGrace83 wrote:I ordered the new RC strategy guide! It will be here by the end of the week and I am super excited. Do all the Manhattan geeks have something to do with its conception? Just wondering...

Yay! I'm so glad you got it! I personally think it's a SUPER AWESOME step forward in thinking about RC. I'd love to know what you think of it as you work through it!

A *lot* of teachers have helped with the process of building the book - not everyone, and not everyone to the same degree, but it's definitely been an extremely collaborative process amongst a lot of super smart geeks here!

It's been a long week since I've picked your brain but I have a question for you. I'm looking at 23-2-14 (Kim: in northern Europe / Lee: Your explanation seems unlikely). I would like to make sure my understanding of this argument (and the way to attack arguments like this) is correct.

Kim:

• 18th century N.Europe had less solemn death rites and a more optimistic view of human condition posed by philosophers
  →
  This change is a result of dramatic increase in life expectancy

Lee:

• Your explanation is not correct unless people were aware of life expectancy increase
  →
  Your explanation is unlikely

We are supposed to defend Kim's explanation. In other words, we are supposed to say either that (1) Lee is wrong or (2) Lee is right but it still doesn't lead to the conclusion. As an LSAT taker, I am wondering if option (1) can even be valid! This is because Lee gives us a premise - that IF people were not aware of the increase in life expectancy THEN it could not have actually been that increase that led to the change in attitude. Since we know we aren't allowed to question a premise, am I right to think that we can never just blindly assume that Lee is wrong to say that (~Awareness → ~Change)? With this in mind, I would assume that we have to proceed with option (2), that Lee is in fact right but his interpretation doesn't affect Kim's argument the way that he wants it to.

So I guess we could show that the people were actually aware of the life expectancy but that seems to easy. We could also show that an increase in life expectancy brought about other consequences. When people live longer, this tends to mean that they are happier or healthier. Maybe this is why the change in attitude happened.
=====

• (A) seems to address this gap. It says that (life expectancy increase → economic changes → influence attitudes). This makes sense! However, I do have a question about this answer. If (A) were the case, would we not be also saying that the people were in fact aware of the life expectancy increase? After all, Lee says that (Change in Attitude → Awareness of Life Expectancy). If we add this to the causal chain that (A) gives, we get the following:
  
  • Life expectancy increase → economic changes → influence attitudes → Awareness of Life Expectancy
    
    So if I have all of these thoughts correct, then is it true that Kim is just agreeing with Lee (saying that they DID in fact have awareness) but doing it in such a way that helps her argument? It seems to be so.
    
    (B) The problem with this is that we don't know if people actually had information about their life expectancy. From Lee's statement, we DO know what happens if people are not aware of their increase in life expectancy - their attitudes could not have changed in response to this increase. By the same token, we DO know what happens if Kim's conclusion is correct - people were aware of their increase in life expectancy. However, this fails to satisfy any sufficient condition and it just seems off base. However, (B) looks really good if we flip it around, saying that "Present-day psychologists have noted that people's attitudes toward life can change in response to an increase in life expectancy." This is because it shows that life expectancy increases (even without information) can change people's attitudes. This is basically what (A) is saying.
    
    (C) This is just ridiculous. Who cares about those conjectures.
    
    (D) This one I think is a bit interesting. However, we are not interested in talking about the concept of life expectancy as we are about the actual happening of an increase in life expectancy. Something can happen without us being totally familiar with what it is. If the concept was not developed yet, it doesn't really mean anything.
    
    (E) If anything, this weakens just a bit. It is saying that life expectancy increases couldn't determine attitudes as well as religious teaching could. However, we know nothing about religious teaching so we could probably dismiss this answer as being out of scope anyway.

=====
I hope that makes sense and my thoughts are organized sufficiently. In addition to these wonderings though, I do have one more thought. We couldn't just merely go along with our typical plan of attack for strengthening causal arguments could we? What I mean is that, when we strengthen causal arguments, we either...

• (1) Show the cause with the effect in a similar situation;
  (2) Show the absence of the cause with the absence of the effect;
  (3) show that B didn't cause A rather than A causing B; or
  (4) rule out alternative explanations.

We couldn't do this because we are trying to defend against Lee's criticism. We aren't just merely strengthening Kim's claim - we are strengthening it in a specific way. Thus, we have to shield it against an objection specifically, the objection being that people had to have been aware of this increase.

A similar situation occurs in 21-3-9 ("Smart highway" argument between Eva and Luis). Luis says "but radio already does what you think the smart highway will do" and Eva is like "no it doesn't! The current reports are too short!" We addressed this argument by showing that Eva, while right in her thoughts, could not dismiss Luis's objection. Luis could just say "well we'll make them LONGER!" I hope you see what I mean. My point is that when defending an argument between two people you have to specifically address the counter-argument, right? For example, we couldn't just give an objection against smart highway systems. We would have to tie it into the length of the radio's reports.

If all my thoughts are correct, I think I just stumbled upon another intricacy of the LSAT that will aid my studies further.

WaltGrace83, as always, you have such interesting analyses!

I think, though, that this is going to be one of the increasingly rare times that I have to disagree with you on some fundamentals!

Let's take a hard look at the question stem, which is an admittedly unusual one: "strongest defense ...against...criticism". So, we need to defend Kim's argument from something that Lee says - but we're never told what! So this statement of yours:

In other words, we are supposed to say either that (1) Lee is wrong or (2) Lee is right but it still doesn't lead to the conclusion.

is spot on!

Now, we talk a lot about never questioning premises, but that actually only applies when we are being asked to analyze someone's argument. In other words, when you are being asked what an argument assumes, to strengthen an argument, to weaken an argument, why an argument is flawed, what principle justifies the argument, etc, you must accept a premise as true so that we can assess the logic. But we aren't being asked to do any of those things in regards to Lee's argument. We're only being asked to protect Kim's argument from whatever Lee says.

If we were going to defend Kim by undermining Lee's logic, the only way we can do that would be to show that it's likely that people were aware of the change in life expectancy. You nailed his core:

• PREMISE: IF not aware (life expectancy change) → explanation not correct
  CONCLUSION: Explanation not likely

Lee is assuming that it's unlikely that people were aware of the change in life expectancy. That's the only real assumption he's making, so that's the only way we could criticize his argument.

And frankly, (A) doesn't do that. I think you may have made a critical error in attempting to apply Lee's premise - Lee's premise is not "(~Awareness → ~Change)" or "(Change in Attitude → Awareness of Life Expectancy)"but rather that ~Awareness → ~correct explanation. Note that the explanation here that wouldn't be correct is WHY the attitudes changed, not whether they did. In fact, Kim's premise is that attitudes changed. When you express the conditional in Lee's premise this way, it can't hook onto the chain in (A)! So, (A) isn't undermining Lee's logic, because it can't establish that people likely weren't aware - and that's the only way we could attack his logic.

So, if (A) isn't defending Kim by undermining Lee's logic, what is it doing? It's attacking the conditional that is his premise! And that's perfectly legit, because we were only told to defend Kim - we weren't told to do that by analyzing Lee's logic. We could just call him an idiot, and be done! Of course, that wouldn't be very interesting. What makes this far more interesting is that the premise is a conditional, which is always a fun exercise, and that's the whole point of this question. How do you call a conditional a liar? You show that the sufficient-trigger does not necessarily always force the necessary-result. In this instance, since Lee's conditional can be thought of as:

• ~awareness → ~correct explanation, or
  correct explanation → awareness

Undermining this conditional would require us to show that it's possible to have Kim's explanation be correct even without awareness of life expectancy. (A) does exactly that! As you point out, it essentially says that the causal chain is often true that (life expectancy increase → economic changes → influence attitudes). If that were the case, then a life expectancy increase could absolutely be the cause for a change in attitude (i.e., the explanation is correct) with or without any awareness of that change. Thus, (A) breaks the conditional Lee relies upon!

Another way to look at this entire argument is that Lee attempts to point out what he perceives as an assumption that Kim is making:

• 1) Kim makes her argument
  2) Lee says "You're assuming that people were aware of the life expectancy change"
  3) Answer choice (A) is Kim responding: "no, I'm actually not assuming that - I don't need people to be aware for my argument to work just fine"

Let me know your thoughts on all this!

WaltGrace83 wrote: I hope that makes sense and my thoughts are organized sufficiently. In addition to these wonderings though, I do have one more thought. We couldn't just merely go along with our typical plan of attack for strengthening causal arguments could we? What I mean is that, when we strengthen causal arguments, we either...

• (1) Show the cause with the effect in a similar situation;
  (2) Show the absence of the cause with the absence of the effect;
  (3) show that B didn't cause A rather than A causing B; or
  (4) rule out alternative explanations.

We couldn't do this because we are trying to defend against Lee's criticism. We aren't just merely strengthening Kim's claim - we are strengthening it in a specific way. Thus, we have to shield it against an objection specifically, the objection being that people had to have been aware of this increase.

Absolutely - in this particular case, I think (A) would be a perfectly legitimate Strengthener, but not all regular ol' strengtheners would necessarily defend against Lee's particular criticism.

WaltGrace83 wrote: A similar situation occurs in 21-3-9 ("Smart highway" argument between Eva and Luis). Luis says "but radio already does what you think the smart highway will do" and Eva is like "no it doesn't! The current reports are too short!" We addressed this argument by showing that Eva, while right in her thoughts, could not dismiss Luis's objection. Luis could just say "well we'll make them LONGER!" I hope you see what I mean. My point is that when defending an argument between two people you have to specifically address the counter-argument, right? For example, we couldn't just give an objection against smart highway systems. We would have to tie it into the length of the radio's reports.

Right on! If Luis responded with 'But traffic monitoring will cause typhoid!', that would certainly strengthen a general case against the smart highway, but it doesn't do much to strengthen his original challenge, which was that the radio can do all the things the fancy newfangled 'smart highway' is supposed to do.

Now, if his objection had simply been "radios are way better than smart highways", and Eva had responded "Nuh uh, radios have COOTIES", then Luis could strengthen his original objection by saying something like "Whatever! Radios spread rainbows and happiness wherever they are" that would be legit. That's because Eva's response breaks down into a core:

• PREMISE: Radios have cooties
  CONCLUSION: Smart highways are obviously better

For Luis to respond, and defend his original argument that radios are better, he could either attack Eva's premise (by saying that radios don't have cooties) or by attacking her conclusion (that smart highways are obviously better).

But this still all falls in line with the general idea that the responder will need to deal with what the other party raised - they just may sidestep a premise and only deal with the conclusion of that other party, or vice versa, so be vigilant.

Keep up the awesome work!!









All of you are welcome to leave questions here, as I check this thread regularly. Feel free to ask questions about the LSAT in general, work out specific LSAT questions, ask for study advice, or ask questions about our books. Or anything else LSAT!

Thanks for the response! It's great! I gave it a quick read but I am going to really think about some of the things you are saying later today when I have the time to do so.

Christine (MLSAT) wrote: So this statement of yours:" In other words, we are supposed to say either that (1) Lee is wrong or (2) Lee is right but it still doesn't lead to the conclusion." is spot on!

Okay so just to clarify. (1) is actually a perfectly legitimate way to defend Kim's argument from Lee's? A correct answer could more or less say something like "Lee assumes something that is not true." Now I know that wouldn't be the best (or perhaps even a very good) answer because all it does is just negate Lee's argument to thereby provide no counter-argument to defend against, but you understand my point? The point is that Lee's argument - and I suppose all counter-arguments set up in this form - do NOT need to be taken as true?

I really appreciate the insight, once again. Now I know more about the LSAT: we should defend against the points raised! Thanks a lot.

WaltGrace83 wrote:

Christine (MLSAT) wrote: So this statement of yours:" In other words, we are supposed to say either that (1) Lee is wrong or (2) Lee is right but it still doesn't lead to the conclusion." is spot on!

Okay so just to clarify. (1) is actually a perfectly legitimate way to defend Kim's argument from Lee's? A correct answer could more or less say something like "Lee assumes something that is not true." Now I know that wouldn't be the best (or perhaps even a very good) answer because all it does is just negate Lee's argument to thereby provide no counter-argument to defend against, but you understand my point? The point is that Lee's argument - and I suppose all counter-arguments set up in this form - do NOT need to be taken as true?

I really appreciate the insight, once again. Now I know more about the LSAT: we should defend against the points raised! Thanks a lot.

It really depends on the question stem itself. We are allowed to just say that Lee is wrong here only because the question stem specifically invited us to defend Kim's argument - i.e., from everything!

If we had been asked instead to weaken Lee's argument (as a way of defending Kim's argument), then we'd be limited once again to the 'respect the premises, attack the logic' pattern we now know and love!

As a strategic note, the fact that we were asked here essentially to just negate a premise of Lee's is unusual. The only thing that makes it an interesting exercise is that the premise is a conditional statement, and negating conditional statements is confusing. If Lee's premise had been a straightforward statement of fact "Purple roses are the best, therefore...", then negating that would be decidedly *uninteresting*. "Nuh uh, no they AREN'T!".

And just to be super nit-picky on your language, if we attacked Lee by saying "something Lee assumes is not true", that's actually attacking his logic. It's an oddness of his particular argument that attacking his logic would actually be simple ("Well, people WERE aware, so there!"), while attacking his premise is a bit more complex. That's not usually the case, and it's probably the only reason the correct answer attacked the premise - and might be the primary reason the question stem is written the way that it is...