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Many people are X, and Many people are Y

Posted: Wed Mar 30, 2011 8:05 pm
by jcdjgd
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Re: Many people are X, and Many people are Y

Posted: Wed Mar 30, 2011 8:08 pm
by paulinaporizkova
jcdjgd wrote:I was under the impression that the word "many" is equal to "some", so if an example such as this one is given, I would NOT be able to infer the statement: Some X are Y, right?...the reason I am asking is because I was given an Q explanation that says that the statement provided is able to yield an inference.

so, ok. many people are x, many people are y. therefore, some x are y.

is this the question? otherwise i'm lost.

also, many = some = one

Re: Many people are X, and Many people are Y

Posted: Wed Mar 30, 2011 8:13 pm
by ThomasMN
Having taken Aristotilian logic, you cannot say that some x are y from the statement that many people are X, many people are Y. All I can infer is that some X are people and some Y are people. Due to what the poster said above, many = some = 1.

However, you might be translating the question correctly. It would be much easier if you posted the question/phrase.

Re: Many people are X, and Many people are Y

Posted: Wed Mar 30, 2011 8:17 pm
by jcdjgd
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Re: Many people are X, and Many people are Y

Posted: Wed Mar 30, 2011 8:19 pm
by dr123
If many are x and many are y. the inference is that there is an overlap and some are both x and y

Re: Many people are X, and Many people are Y

Posted: Wed Mar 30, 2011 8:21 pm
by kehoema2
jcdjgd wrote:Thanks for the replies guys!....just to elaborate...here is the question, which is from the LR Manhattan LSAT book (part of a "Drill" section):

Many cats weigh more than 15 pounds, and many cats are difficult to train.

The inference they claimed to be taken from this is:

Some cats that are difficult to train weigh more than 15 pounds.
I don't see how that is correct. THERE COULD be some cats that are both, but obviously their "inference" does not read that.

If they think many=most, then it would be true. That may be the problem (however, still always read many as some).

Re: Many people are X, and Many people are Y

Posted: Wed Mar 30, 2011 8:22 pm
by paulinaporizkova
dr123 wrote:If many are x and many are y. the inference is that there is an overlap and some are both x and y
it's been almost 2 years since i took the LSAT. can someone remind me in what way an assumption is different than an inference?

Re: Many people are X, and Many people are Y

Posted: Wed Mar 30, 2011 8:23 pm
by RPK34
dr123 wrote:If many are x and many are y. the inference is that there is an overlap and some are both x and y
Nope. I most people are X and most people are Y, then some X are Y. If it just says many, then it doesn't mean there is an overlap.

Re: Many people are X, and Many people are Y

Posted: Wed Mar 30, 2011 8:23 pm
by paulinaporizkova
dr123 wrote:If many are x and many are y. the inference is that there is an overlap and some are both x and y
but all that is saying is that one cat is X and one cat is Y out of an unknown # of cats. therefore, it is very possible that there would be no overlap, unless there is only 1 cat

Re: Many people are X, and Many people are Y

Posted: Wed Mar 30, 2011 8:24 pm
by bball1996
I'm pretty sure it's most z are x and most z are y, then some z are x and y. It doesn't work with many.

Re: Many people are X, and Many people are Y

Posted: Wed Mar 30, 2011 8:25 pm
by Eugenie Danglars
It seems to me that OP's right, and there's an error. (But it's been a while since I've done this.)

If it's most and most, then yes, but many and many doesn't lead to an inference because "many" doesn't have a set number.

Imagine 100 cats. If MOST cats are fat, there have to be at least 51 fat cats. If MOST cats are hard to train, there must be at least 51 rebels. Thus, there's some overlap.

In contrast, if I say many=35, I could have 35 fat ones and 35 rebels with zero overlap.

Am I totally making stuff up here?

Re: Many people are X, and Many people are Y

Posted: Wed Mar 30, 2011 8:26 pm
by jcdjgd
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Re: Many people are X, and Many people are Y

Posted: Wed Mar 30, 2011 8:26 pm
by dr123
An inference can be drawn from info in the stimulus. such as many are x many are y so there must be an overlap and some (at least 1) must be x and y

an assumption is more of an unstated premise

Re: Many people are X, and Many people are Y

Posted: Wed Mar 30, 2011 8:28 pm
by paulinaporizkova
dr123 wrote:An inference can be drawn from info in the stimulus. such as many are x many are y so there must be an overlap and some (at least 1) must be x and y

an assumption is more of an unstated premise
soo an inference is just something that COULD be possible from the stim? because a conclusion like "therefore" makes it sound very dubious

Re: Many people are X, and Many people are Y

Posted: Wed Mar 30, 2011 8:31 pm
by Eugenie Danglars
dr123 wrote:An inference can be drawn from info in the stimulus. such as many are x many are y so there must be an overlap and some (at least 1) must be x and y

an assumption is more of an unstated premise
Pretty sure you're off base here. Many could be 10 or 50 or 2 depending on the situation and who's describing it. It doesn't have a mathematical definition. See cat example above.

Re: Many people are X, and Many people are Y

Posted: Wed Mar 30, 2011 8:32 pm
by dr123
paulinaporizkova wrote:
dr123 wrote:An inference can be drawn from info in the stimulus. such as many are x many are y so there must be an overlap and some (at least 1) must be x and y

an assumption is more of an unstated premise
soo an inference is just something that COULD be possible from the stim? because a conclusion like "therefore" makes it sound very dubious
an inference must be true according to the stimulus, like a --> b / b ---> c the inference would be a --> c. I'm thinking OP might have misread/misinterpreted the question as many when the meant most, cuz if it was many, than I would be wrong

Re: Many people are X, and Many people are Y

Posted: Wed Mar 30, 2011 8:40 pm
by Eugenie Danglars
so basically we all agree that

many x are a, many y are b, therefore some y are a is NOT valid

but

most x are a, most y are b, therefore some y are a IS valid.

right?

Re: Many people are X, and Many people are Y

Posted: Wed Mar 30, 2011 8:42 pm
by Kurst
As others have noted, dr123 is incorrect: no inference can be drawn from two "many" statements. The Manhattan LR book to which jcdjgd refers made an invalid inference.
Eugenie Danglars wrote:most x are a, most y are b, therefore some y are a IS valid.

right?
No. You have four variables that do not necessarily overlap. The statement you were going for is:

Most a are x, most a are y, therefore some x are y.

Re: Many people are X, and Many people are Y

Posted: Wed Mar 30, 2011 8:49 pm
by sundance95
Kurst wrote:As others have noted, dr123 is incorrect: no inference can be drawn from two "many" statements. The Manhattan LR book to which jcdjgd refers made an invalid inference.
Eugenie Danglars wrote:most x are a, most y are b, therefore some y are a IS valid.

right?
No. You have four variables that do not necessarily overlap. The statement you were going for is:

Most x are a, most y are a, therefore some x are y.
This is correct.

Re: Many people are X, and Many people are Y

Posted: Wed Mar 30, 2011 8:50 pm
by Mike@ManhattanLSAT
Hi all - wanted to chime in because I caused this mess -- that is a mistake in the Manhattan LSAT book -- you cannot make that inference and the correct answer is (C) None of the above.

I'm terribly sorry for the mistake, and I hope it hasn't caused you too much confusion. Of course it will be fixed for the next printing.

BTW, here is our complete errata list --

http://www.manhattanlsat.com/forums/err ... 5e2efbe754

I hope you are enjoying the book otherwise, and finding it to be useful!

Mike Kim

Re: Many people are X, and Many people are Y

Posted: Wed Mar 30, 2011 11:48 pm
by suspicious android
God I love threads like these.

Re: Many people are X, and Many people are Y

Posted: Wed Mar 30, 2011 11:58 pm
by well-hello-there
Mike@ManhattanLSAT wrote:Hi all - wanted to chime in because I caused this mess -- that is a mistake in the Manhattan LSAT book -- you cannot make that inference and the correct answer is (C) None of the above.

I'm terribly sorry for the mistake, and I hope it hasn't caused you too much confusion. Of course it will be fixed for the next printing. Mike Kim
Was the mistake made because at the time, you thought that many=more than 50% ? Or was it just a typo? fess up now :wink:

Re: Many people are X, and Many people are Y

Posted: Thu Mar 31, 2011 12:11 am
by Eugenie Danglars
Kurst wrote:As others have noted, dr123 is incorrect: no inference can be drawn from two "many" statements. The Manhattan LR book to which jcdjgd refers made an invalid inference.
Eugenie Danglars wrote:most x are a, most y are b, therefore some y are a IS valid.

right?
No. You have four variables that do not necessarily overlap. The statement you were going for is:

Most a are x, most a are y, therefore some x are y.
Whoops, my bad. That's what I get for doing logic before I finish my coffee.

Re: Many people are X, and Many people are Y

Posted: Thu Mar 31, 2011 12:16 am
by Jack Smirks
I think Mike@Manhattan owes someone some money back.

Re: Many people are X, and Many people are Y

Posted: Thu Mar 31, 2011 1:25 am
by BrianOz1
Many = > 50%. there has to be overlap. I don't understand the debate.