Q22 - The folktale that claims that

[talamaar]

I missed two problems on this exam that I didn't understand why. I missed others, but that's because I don't know how to read apparently.

This question deals with rattlesnakes and the assumption that is required in order for the conclusion to be properly drawn.

After reading the answer (E) and thinking about it, I still don't understand why that's the answer. The question doesn't deal with food at all, but age determined by the the tail of the rattlesnake. Unless this book is mistaken (I doubt it), can someone please enlighten me?

[noah]

Interesting how so many people find they apparently can't read when they start studying for the LSAT!

With P22, start by identifying the conclusion: if the tails were not brittle, we could tell how old the snakes are from the number of sections in their tails.

Why? (i.e. what's the proof/premise?): because these snakes grow a new section each time it molts.

Most people get trapped by (A), forgetting that once a month would be just as useful a rhythm for detecting age (just divide the number by 12!). (E) is correct because the molting rhythm needs to be regular. If snake X molts once a year, and snake Y molts 3 times a year, how will we know how to relate the number of molts and the snake's age? (E) outlines and dismisses a possible reason that the molting would not by regular, in effect pointing out a hole in the argument and filling it in at the same time.

The sign of a necessary assumption is that if you negate it, the argument falls apart. If rattlesnakes molt differently depending on their diet, will we be able to tell the age of the snakes from the segments (assuming they weren't so darn brittle)?

An analogous argument might be: We could tell how old an LSAT tree is if we were allowed to chop it down. Let's assume that we were worried that LSAT trees make new rings only in years when there are 100 days of sun or more. That would be a problem -- counting rings would not work on its own anymore. So, something that would strengthen this hypothetical argument might be "LSAT trees make rings as often when there is 100 days of sun as they do when there is not"

Does that clear it up or have I just added to the confusion?

#officialexplanation

[talamaar]

Very much. Thank you. I see that now.

[backupbecool]

I was wondeirng why the answer is not D. Humor me, please, I selected it, but realized it may the exact opposite of what I thought it had been.

[noah]

(D) is tricky. However, if you peel back a few layers, what it's really suggesting is that the argument requires that there isn't a different way to find a rattlesnake's age (by the brittleness of the tail). However, if that method of determining a snake's age were possible - i.e. the negation of (D) - the argument would still make sense. Thus, it's not necessary.

Does that make sense?

[pathosj]

Can someone explain to me the negation technique that noah uses? I've seen it often in the responses, but I don't know how to use it properly.

With the LSAT one week away, it may not be wise to adopt a new technique, but I would like to know how to make sense of responses when explanations use this technique.

Thank you.

[patrice.antoine]

Bump.

Can (D) not also be eliminated on the basis of "length of the rattlesnakes life" ? I don't consider this the same as "age". I do wonder though, if it read as is but included "not correlated with age", if that would have been a necessary assumption to the argument...

[hyewonkim89]

(D) is tricky. However, if you peel back a few layers, what it's really suggesting is that the argument requires that there isn't a different way to find a rattlesnake's age (by the brittleness of the tail). However, if that method of determining a snake's age were possible - i.e. the negation of (D) - the argument would still make sense. Thus, it's not necessary.

Does that make sense?

Hello Noah,

I'm still having a hard time eliminating D.

When I negate it, wouldn't it be "the brittleness of a rattlesnake's rattle is correlated with the length of the rattlesnake's life?"

If so, wouldn't it destroy the argument by giving us another way to know the snake's age?

Sorry I just don't see how it still makes sense.

Thanks for your help in advance!

[noah]

When I negate it, wouldn't it be "the brittleness of a rattlesnake's rattle is correlated with the length of the rattlesnake's life?"

If so, wouldn't it destroy the argument by giving us another way to know the snake's age?

Sorry I just don't see how it still makes sense.

How does that destroy the argument that we could tell the age of a snake another way?

For example, take this argument: Because lady bugs get a new spot every year we can tell their age by counting up the spots.

Is it a problem if we could tell the age of a ladybug by measuring its weight? Why can't there be two ways to tell the age of a ladybug?

[hyewonkim89]

OHH, I see your point now.

For some reason, I kept thinking there had to be only one way of telling the snake's age.

Thank you!

[gplaya123]

This is claimed to be one of the difficult questions on LSAT according to online forums...
but this is way more simpler than it looks like.
First, you have to acknowledge the fact that it's hypothetical situation.
IF the rattle isn't brittle...
this is the PREMISE that you must accept first before doing anything.
Now, we are working in the context and the world where rattle isn't brittle but rather strong as a steel (extreme but just accept it).

Now, the conclusion is that counting each section would RELIABLY tell the age.
Why?
Because each time the snake molts, it creates a new section.
Sounds good.
Now, what's the assumption?
It's all about alternatives: is there any other process that could affect the frequency of molting?

People are caught up with A a lot but they shouldn't be.
How many times a snake molt is irrelevant.
Because if they molt like 30000 times a year, then they would have 30000 sections that year.
If 30, then 30 sections so forth.
But... we have to again think about what can alter the rate of molting, which brings E the answer: if diet affect the "rate," it CANNOT RELIABLY tell the age.

twin rattle snakes were taken to two different areas, one in desert and one in forest, to be raised. The one that lived in former area had no access to water or food. The latter did.
Imagine, according to E, the desert snake does not molt as much as the forest snake even though they were born on the same day (they are twins right?) And what do we know about not molting? it means less sections formed. What does that mean? 3 years later, perhaps the first one has 3 sections whereas the other one has 100. Now, can we conclude that one is 3 years old and the other one is 100 years old?
nope...

that's why we need E to defend this argument.

B and C are irrelevant. They do not talk about the rate at all.

D is trying to say that oh, the older snake is, the more brittle it is. But who cares about how brittle it is right?
Brittleness is taken care of by the stimulus. (again we are talking about hypo world)
hope this helps

[rickytucker]

It's also worthy to note that the crux of the argument relies on a constant rate of change. In (E), this is indicated by: "as often" which shows that the rate in which a snake molts is constant. The comparison involving food that comes after "as often" is not so important because one could just as easily say, "rattlesnakes molt as often when a republican is in office as they do when a democrat is in office", and the answer would still be correct. The core relies on the assumption that the rate of molt doesn't change.

I'd also like to emphasize how the test makers are trying to play mind games in this question. They try to lure you in with an attractive incorrect "bait" answer from the onset so that you choose it with confidence without spending time to review the other choices. It's also not a coincidence that they place the actual correct answer dead last to make you work for it.

One final note about (A): It's tricky because the test makers try to exploit our preconceived notions that age can only be measured in increments of 365 day cycles, which need not necessarily be the case. We should always be attentive to the fact that we all have preconceived notions.

[WaltGrace1983]

I have a question about (D) that really applies to the LSAT as a whole. When a conclusion is a hypothetical (if-then statement), we would never have to explain or question the sufficient condition, correct? It seems we are just supposed to take it as truth - just like we would any premise in an argument.

As I understand it, a correct answer to a necessary assumption wouldn't simply provide more reasons to believe the premise or give reasons why the premise is the way it is, etc. The correct answer is obviously going to attack the gap between the premise and conclusion.

So would I be right by eliminating (D) by simply saying, "Yea but who cares? We are discussing what would happen IF the rattles were not so brittle!" This is something I have been wondering since I revisited 28.1.21 ("Some astrologers claim...Toronto...New York...personality tests..."). It seems that something like (B) could never be right because it merely EXPLAINS the personality tests. But we don't care about that! We are talking about the implications of those tests. This seems similar to what is going on here. We don't care about the brittleness! We want to talk about other stuff!

Any insight is appreciated!

[ohthatpatrick]

That's exactly right.

When the conclusion is a conditional, we should always think of the IF part of it as a given (something we're not trying to fight). A lot of trap answers try to call into question whether the sufficient idea would ever come true.

The author is NOT assuming the sufficient idea is likely or even necessarily possible.

Our job is disputing these authors is to find a way that EVEN IF the left side were true, the right side could still be false.

So I would try to generate an objection to this argument by thinking, "even if all a rattlesnake's rattle retained all its sections, you STILL could not reliably determine its age from its number of sections".

[ying_yingjj]

I just feel I have to write something about this question.

No wonder the top 10 law school graduates can not find a lawyer job these days if what they were tested on was this kind of nonsense rattle snake crap.

To all LSAT students, very quickly, getting into law school is not the only way to become a lawyer, you can go to online law schools as long as they are accredited by ABA.

LSAT tells us not to use personal knowledge to do the questions. I was raised in the city, I have no idea how many times rattle snakes molt, and I thought it was once a year. So I chose A.

There is no any indication in the stimulus telling us rattle snake may molt several times a year, I don't live with them and observe them, so I thought if they molt once a year (maybe there is certain kind of rattle snake really molt once a year), then that's the necessary assumption for the conclusion to draw.

This is a typical example telling me that LSAC's is double standard on their questions.

[Harmmanb]

I just feel I have to write something about this question.

No wonder the top 10 law school graduates can not find a lawyer job these days if what they were tested on was this kind of nonsense rattle snake crap.

To all LSAT students, very quickly, getting into law school is not the only way to become a lawyer, you can go to online law schools as long as they are accredited by ABA.

LSAT tells us not to use personal knowledge to do the questions. I was raised in the city, I have no idea how many times rattle snakes molt, and I thought it was once a year. So I chose A.

There is no any indication in the stimulus telling us rattle snake may molt several times a year, I don't live with them and observe them, so I thought if they molt once a year (maybe there is certain kind of rattle snake really molt once a year), then that's the necessary assumption for the conclusion to draw.

This is a typical example telling me that LSAC's is double standard on their questions.

LSAC defiantly does not have a double standard, they actually changed the test to control for socioeconomic factors and took diversity into account, they also test each question to make sure it is not biased unfairly to any one specific group. Your post indicates that perhaps you do not understand some of the basics concerning logic. I would start by studying the differences are between MBT/inference questions and assumption questions, they are not the same thing. Inference questions for example use deductive logic, where as the majority of the other question types use inductive reasoning. Think of assumptions as being necessary components of the argument that must be believed by the author before the conclusion is derived from the premises in a conditional way and think of inference as conclusions that you derive deductively from the fact set in the stimuli, which you can think of as premises that support that conclusion. If you have trouble with English, then try to get some help with that before hand. I think it would be very difficult for LSAC to make the test not biased towards English speakers since they are assuming you want to go to a law schools in the US, where law is taught primarily in English.

[tommywallach]

Yep. The question is entirely fair, and has nothing to do with preexisting knowledge about rattlesnakes.

-t

[hwangbo.edu]

I just feel I have to write something about this question.

No wonder the top 10 law school graduates can not find a lawyer job these days if what they were tested on was this kind of nonsense rattle snake crap.

To all LSAT students, very quickly, getting into law school is not the only way to become a lawyer, you can go to online law schools as long as they are accredited by ABA.

LSAT tells us not to use personal knowledge to do the questions. I was raised in the city, I have no idea how many times rattle snakes molt, and I thought it was once a year. So I chose A.

There is no any indication in the stimulus telling us rattle snake may molt several times a year, I don't live with them and observe them, so I thought if they molt once a year (maybe there is certain kind of rattle snake really molt once a year), then that's the necessary assumption for the conclusion to draw.

This is a typical example telling me that LSAC's is double standard on their questions.

It's true not everyone should pursue law - especially those counseling contradictory advice based on personal frustration. How does one claim "top 10" law school graduates cannot find lawyer jobs, and then advises "all LSAT students" to pursue law online instead? Instead of crying foul and blaming others, perhaps a better approach is to learn from this elegant question the difference between a Sufficient (e.g., Answer A) and Necessary Assumption (credited response). Thankfully, the LSAT is very learnable for those willing and able to put forth the effort.

[tommywallach]

Well said, hwangbo!

[gultekincan92]

The stem says that we are looking for an assumption the argument "requires" in order for its conclusion to be "properly drawn". So does this mean that we are looking for an assumption which is necessary and sufficient?

We have another example of this type of stem at PT 33, S1, 10.