How to diagram the phrase "the only"

secretad
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How to diagram the phrase "the only"

Postby secretad » Thu Mar 31, 2011 5:20 am

I think the phrase "the only" ALWAYS implies an if and only if scenario.

For example.....The only fruits are apples.

f ---> a
a ---> f

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Kabuo
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Re: How to diagram the phrase "the only"

Postby Kabuo » Thu Mar 31, 2011 5:53 am

How about the only people who eat tofu are vegetarians. This is just t -> v. v -> t would be a mistaken reversal.

Kurst
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Re: How to diagram the phrase "the only"

Postby Kurst » Thu Mar 31, 2011 11:45 am

The only Republicans are Fox News correspondents.

It does not follow that every Fox News correspondent is a Republican.

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homestyle28
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Re: How to diagram the phrase "the only"

Postby homestyle28 » Thu Mar 31, 2011 11:49 am

secretad wrote:I think the phrase "the only" ALWAYS implies an if and only if scenario.

For example.....The only fruits are apples.

f ---> a
a ---> f


The only A are B, means that if you have an A, you have a B. Not the other way 'round.

bp shinners
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Re: How to diagram the phrase "the only"

Postby bp shinners » Fri Apr 01, 2011 1:31 am

I think you're making a primary mistake on the LSAT, which is taking outside knowledge into it. You're saying that a-->f because you know that to be true; however, it's doesn't logically follow from the statement you present.

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YaSvoboden
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Re: How to diagram the phrase "the only"

Postby YaSvoboden » Fri Apr 01, 2011 3:55 am

Kabuo wrote:How about the only people who eat tofu are vegetarians. This is just t -> v. v -> t would be a mistaken reversal.


Maybe I am misunderstanding diagrams, or just have some flawed thinking, but aren't "the only people who eat tofu are vegetarians" and "only vegetarians eat tofu" the same thing? Sure, vegetarians can eat other things, would v->t be saying that vegetarians only eat tofu?

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Kabuo
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Re: How to diagram the phrase "the only"

Postby Kabuo » Fri Apr 01, 2011 4:40 am

YaSvoboden wrote:
Kabuo wrote:How about the only people who eat tofu are vegetarians. This is just t -> v. v -> t would be a mistaken reversal.


Maybe I am misunderstanding diagrams, or just have some flawed thinking, but aren't "the only people who eat tofu are vegetarians" and "only vegetarians eat tofu" the same thing? Sure, vegetarians can eat other things, would v->t be saying that vegetarians only eat tofu?


Your rephrase is just that: a rephrase. It's tautological, and thus, correct. But "only vegetarians eat tofu" is diagrammed the same way as "the only people who eat tofu are vegetarian." They are both "if you eat tofu, you are necessarily vegetarian." v->t is still a logical jump. You're just changing the location of the word "only" and confusing which side of the conditional statement it applies to in the process.

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EarlCat
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Re: How to diagram the phrase "the only"

Postby EarlCat » Sun Apr 03, 2011 12:42 pm

secretad wrote:I think the phrase "the only" ALWAYS implies an if and only if scenario.

For example.....The only fruits are apples.

f ---> a
a ---> f


Are you sure?

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