The Official June 2015 Study Group Forum

[calmike]

Oh man, Am i getting nervous about the LSAT or what

[Big Red]

Lol I forgot how absurd this test is

[appind]

Yes!! That's it exactly! A most statement that gives me info on the pool of unskilled workers would be irrelevant. A most statement that gives me info on the pool of entry-level workers would be relevant (and that's what choice (B) does).

In exactly the same way, on q8(A), a most statement that gives me info on the pool of glacier-moved boulders is irrelevant (and that's what choice (A) does). A most statement that gave me info on the pool of >100-miles boulders would be more useful.

For both of these, it works this way because we know that Garon was an entry-level worker, and we know the boulder is >100-miles - relevant data is about the pool that we know they ARE in.

This is the thing that I'd really take away from this question - how the LSAT plays on our expectations with 'most' statements. If q8.(A) had said "Most boulders that have been moved >100-miles from their birthplace have not been moved by glaciers." I would absolutely choose that as a weakener, without hesitation.

They love to take 'most' and 'some' statements that would work, then twist them into something that doesn't work by inverting and/or negating them. If you can recognize quickly that the elements of the statement are in the wrong place to be useful, then you can save yourself a lot of parsing of the language. I'm far more likely to be able to catch the backwards-ness of the most statement quickly than I am the more subtle language issue you've picked up on below, and on a Q8, I'm aiming to be moving pretty fast.

Great observation! You're right that the argument doesn't actually conclude that it was moved the entire 100+ miles by a glacier, just that it was "probably deposited here....by a glacier". The does leave open the possibility that aliens moved it the vast majority of the distance, and then a glacier moved it the last little bit. We need a glacier to move it for the conclusion to make sense, but not necessary the whole 100 miles.

good stuff.

in the Fluffy cat example you mention the role of 'some' in weakening, can some also str? would it str if q8 had been a str question and 8.A said "some/several boulders that have been moved 100+ miles from their birthplace have been moved by southward moving glaciers" or "most boulders that have been moved any distance from their birthplace have been moved by southward moving glaciers." since the latter is discussing a bigger group of boulders ("any distance"), assume that stim concludes that entire 100+ miles is moved by glacier because not assuming it would make latter very straightforward.
ps: noticed that since the stim is only concerned southward-moving glaciers, "most boulders that have been moved 100+ miles from their birthplace have been moved by glaciers" would not str as the argument is not interested in the whole set of glaciers but only a subset that is southward moving.

[Jeffort]

i think i see your reasoning; had q3.B said "most of the unskilled workers acme hires are in non entry level positions," then the 3.B will have similar structure as 8.A, and then this modified 3.B wouldn't have weakened at all. for completeness, the actual q3 looks like this.
q3:
assumption: Garon is B (B=unskilled, A=workers)
choice B: some A are not B
valid weakner inference: Garon is likely not B

Yes!! That's it exactly! A most statement that gives me info on the pool of unskilled workers would be irrelevant. A most statement that gives me info on the pool of entry-level workers would be relevant (and that's what choice (B) does).

In exactly the same way, on q8(A), a most statement that gives me info on the pool of glacier-moved boulders is irrelevant (and that's what choice (A) does). A most statement that gave me info on the pool of >100-miles boulders would be more useful.

For both of these, it works this way because we know that Garon was an entry-level worker, and we know the boulder is >100-miles - relevant data is about the pool that we know they ARE in.

This is the thing that I'd really take away from this question - how the LSAT plays on our expectations with 'most' statements. If q8.(A) had said "Most boulders that have been moved >100-miles from their birthplace have not been moved by glaciers." I would absolutely choose that as a weakener, without hesitation.

They love to take 'most' and 'some' statements that would work, then twist them into something that doesn't work by inverting and/or negating them. If you can recognize quickly that the elements of the statement are in the wrong place to be useful, then you can save yourself a lot of parsing of the language. I'm far more likely to be able to catch the backwards-ness of the most statement quickly than I am the more subtle language issue you've picked up on below, and on a Q8, I'm aiming to be moving pretty fast.

noticed that 8.A may be wrong even without this. the argument doesn't say that boulder is moved >100 miles only by glacier, it only says that it's >100 miles from its birthplace. so it's actually not a premise at all in the stim that glacier has to move the boulder more than 100 miles.
http://www.top-law-schools.com/forums/v ... r#p2509207

Great observation! You're right that the argument doesn't actually conclude that it was moved the entire 100+ miles by a glacier, just that it was "probably deposited here....by a glacier". The does leave open the possibility that aliens moved it the vast majority of the distance, and then a glacier moved it the last little bit. We need a glacier to move it for the conclusion to make sense, but not necessary the whole 100 miles.

The bolded part above and Christine's explanations of the logical concepts behind why trap answer (A) on Q8 is irrelevant yet sounds like an attractive answer deserves emphasis because it's a commonly repeated form of attractive trap answer the test writers love to offer in weaken and strengthen questions as well as in other question types.

The test writers frequently offer trap answers that are basically the reversal and/or negated (think mistaken reversal and mistaken negation conditional reasoning flaws) form of a premise that would logically work to answer the question. Just like with normal conditional premises (All A's are B's, If A then B, etc.), the reversal or negation of a 'most' conditional premise is a logically flawed inference to draw from the premise.

AC (A) in the glacier question is actually even more devious than just offering a reversed or negated version of a conditional premise that would logically work. To make it sound even more attractive and harder to understand why it doesn't work, AC (A) is the reversed and negated form of a 'most' premise that would weaken the argument.

(A) states the contrapositive form of the 'most' premise that would work, making it sound good since we know that the contrapositive (reverse and negate the conditions from both sides) of standard conditionals are logically valid implicitly true premises from a given standard (rather than formal logic 'most' or 'some') conditional premise. That logical structure makes it sound and intuitively feel logically valid since the reversed and negated contrapositive of normal conditionals is valid logic. However, the contrapostive form of a 'most' or 'some' conditional premise is not a logically valid inference/implicit premise you can draw from the stated premise. The contrapositive form is only logically valid from a standard all/none/If...then absolute quantifier conditional premise but is logically invalid with 'some' and 'most' conditional premises.

It's not really emphasized or addressed much in prep books or classes, but it's important to remember that the contrapostive is only a valid method of reasoning tool with absolute/universal quantifier standard conditional premises and does not apply to 'formal logic' conditional premises with non absolute quantifiers such as few, some, many, or most.

Q#8 glacier question sucker choice:

(A) BMG --most--> ~M100+

(BMG = boulder moved by glacier, M100+ = moved more than 100 miles)

contrapositive form by simply reversing and negating like we can only logically do with standard conditionals:

M100+ --most--> ~BMG

If the contrapositive of 'most' conditionals was a logically valid implicit premise/inference, we'd have something that weakens since we know the boulder was moved more than 100 miles and would thus have a premise telling us that it's not probable the boulder was moved by a glacier. The contrapositive form of a non absolute conditional premise (quantifiers few, some, many, most) is not a logically valid premise/implicit/inherent inference from the stated premise because those 'formal logic' conditional premises do not establish an absolute/universal relationship that is guaranteed true of every member of the sufficient condition group/set of things. It's a really well structured inviting attractive sucker choice, which is why the test writers repeat variations of it over and over to nail people.


For further illustration of the concepts Christine explained, take a look at this high difficulty level describe the flaw LR question. It contains an argument that commits the same flaw/makes the same type of invalid inference from the same type of premise Christine described that people frequently make in their head from these types of tempting 'most' premise trap answers on wkn and str questions: PT 30 LR1 Q#17

The correct answer directly states exactly what Christine discussed and explained about 'most' statements concerning which element(s) they allow you to make an inference about. It should help further illustrate why it's imperative and also efficient to prioritize identifying which elements are which (sufficient vs. necessary) in given AC's and/or premises to help you quickly identify what you can and cannot infer, and help recognize and toss out attractive traps quickly that are wrong because they simply have the elements reversed and/or negated from what would otherwise work to answer the question and/or give you a valid inference.

Simple way to think about it is that the sufficient condition element is the subject of the premise and is what the premise gives you information about/is something you can infer something else about. Whereas the premise doesn't give you any information about the necessary condition element(s) set, so you cannot draw any valid inferences about what other things are true about the necessary condition element(s) set from the given premise. This conceptual aspect of conditional reasoning is why in some logic books the necessary condition is referred to as the consequent, meaning it's the thing you can infer is consequentially true about the subject of the premise/the sufficient condition element(s) set.

Attractive trap answers that are basically just the reversed or negated form of a conditional premise that would otherwise qualify as a CR for the question (tempting your brain to engage in mistaken reversal or mistaken negation flawed conditional reasoning in your head to rationalize picking the sucker choice) appear all over the place in LR questions of various types beyond just weaken and strengthen. AC's with the correct elements but that has them reversed and/or negated from a conditional form that would otherwise work are offered as tempting sucker choices frequently in almost all LR question types.

I hope this helps bring more clarity about the concepts rather than being confusing.

[Rigo]

Only been driving an hour and I'm already over it.

[biggestlawman]

Only been driving an hour and I'm already over it.

The road toperdition is long and lonely!

[The Abyss]

Only been driving an hour and I'm already over it.

I'll be driving from Laramie, Wyoming to Atlanta, Georgia by myself starting Friday. Two days of driving. Roughly 14 or 15 hours each day of driving. It's a pretty boring drive too.

That said, I usually enjoy road trips and driving long distances. Crank up the music, get a big cup of coffee, set the cruise control and enjoy.

[Big Red]

Only been driving an hour and I'm already over it.

I'll be driving from Laramie, Wyoming to Atlanta, Georgia by myself starting Friday. Two days of driving. Roughly 14 or 15 hours each day of driving. It's a pretty boring drive too.

Dude that's A LOT to do in a day, 12 is where I just about max out

[The Abyss]

Only been driving an hour and I'm already over it.

I'll be driving from Laramie, Wyoming to Atlanta, Georgia by myself starting Friday. Two days of driving. Roughly 14 or 15 hours each day of driving. It's a pretty boring drive too.

Dude that's A LOT to do in a day, 12 is where I just about max out

It's really about 12 hours of driving, 14 or 15 hours including stops for gas, stretching, eating, etc.

I've done this drive a few times without incident or scares, and I'll stop if I get super drowsy.

[Rigo]

Only been driving an hour and I'm already over it.

I'll be driving from Laramie, Wyoming to Atlanta, Georgia by myself starting Friday. Two days of driving. Roughly 14 or 15 hours each day of driving. It's a pretty boring drive too.

That said, I usually enjoy road trips and driving long distances. Crank up the music, get a big cup of coffee, set the cruise control and enjoy.

Yeah I'm getting in the groove. I used to drive Illinois to New York and vice versa in a day so I can definitely pull long distances. I'm in the groove now. Want to make it to at least Wisconsin.

Annoyed that Starbucks are few and far between at rest stops though. I'm not doing Dunkin or McDobalds.

[RZ5646]

http://arstechnica.com/cars/2015/05/fre ... ing-truck/

[gamerish]

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[Rigo]

Messed up the grading on my PT. 163 -> 164 and 177 -> 175.

Uhh good I guess?

[gamerish]

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[Rigo]

Yay I finally got my Starbucks in Erie, PA.
ZACBORO WHERE ARE YOU?

[Rigo]

Shalom Ohio. Please curb your enthusiasm, thread.

[Big Red]

Shalom Ohio. Please curb your enthusiasm, thread.

Tell Ohio I said hello

This thread is pretty dead considering how close the test is. Must be that people are actually focused up, wouldn't know too much about that. Anyway, been drilling pretty hard and it's funny how quick LG comes back and how LR is a different language. I think I might die -4/5 on RC

[pta]

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[Rigo]

I listened to both Blackout and Greatest Hits by Britney so far this trip. She really gets me amped up to drive.

[pta]

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[The Abyss]

Shalom Ohio. Please curb your enthusiasm, thread.

Ughhh. Worst state in the Union.

[Rigo]

JFC Cleveland is bleak.

[TheWalkingDebt]

JFC Cleveland is bleak.

Somehow Akron is worse.

[Rigo]

JFC Cleveland is bleak.

Somehow Akron is worse.

The only Ohio city I've ever heard good things about is Columbus.

[TheProdigal]

JFC Cleveland is bleak.

Somehow Akron is worse.

The only Ohio city I've ever heard good things about is Columbus.

There are good things to be said about many Ohio cities.

At least it isn't Akron.
At least it isn't Cleveland.
At least it isn't Dayton? (If their LS e-mails me one more time...)
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...

Yeah, that's about it.