Formal Logic

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stray
Posts: 213
Joined: Thu Dec 23, 2010 12:18 pm

Formal Logic

Postby stray » Sat Jun 22, 2013 9:55 pm

A some B <-/-> C --> D

That is a double not arrow. Can someone explain to me why an inference cant be A some D?
I know A some C is one by why not the other?

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TheMostDangerousLG
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Joined: Thu Nov 22, 2012 4:25 am

Re: Formal Logic

Postby TheMostDangerousLG » Sat Jun 22, 2013 9:58 pm

ColumbiaBigLaw wrote:A some B <-/-> C --> D

That is a double not arrow. Can someone explain to me why an inference cant be A some D?
I know A some C is one by why not the other?


I don't exactly understand what you're asking..

If "some A are B", and "no B are Cs", then you can't infer "some As are Cs", you can only infer "some As are not Cs". You can't say anything about the relationship between A and D.

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stray
Posts: 213
Joined: Thu Dec 23, 2010 12:18 pm

Re: Formal Logic

Postby stray » Sat Jun 22, 2013 10:09 pm

TheMostDangerousLG wrote:
ColumbiaBigLaw wrote:A some B <-/-> C --> D

That is a double not arrow. Can someone explain to me why an inference cant be A some D?
I know A some C is one by why not the other?


I don't exactly understand what you're asking..

If "some A are B", and "no B are Cs", then you can't infer "some As are Cs", you can only infer "some As are not Cs". You can't say anything about the relationship between A and D.


Whoops, sorry man. I meant Some A's are not C's as an inference. And about A and D I was under the impression that you could for some reason. But nvm, It actually doesnt even make sense for there to be a relationship between A and D when I actually say it out.




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