Help with this logical reasoning problem

Sjawilton
Posts: 6
Joined: Thu Jul 26, 2012 6:46 am

Help with this logical reasoning problem

Postby Sjawilton » Tue Sep 18, 2012 9:54 am

I got this problem correct, but it took me a (valuable) minute or two longer than it should have.
Any suggestions for quick diagramming?

"My father likes turnips, but not potatoes, which he says are tasteless. So it is not true that whoever likes potatoes likes turnips.

The flawed reasoning in the argument above most closely resembles that in which one of the following?

*Correct answer: Although this recently published work of fiction has more than 75 pages, it is not a novel. Thus, it is not the case that all novels have more than 75 pages."

It is quite intuitive after looking at it again, but a suggestion for a quick diagram would be great.

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CardozoLaw09
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Joined: Sat Aug 28, 2010 1:58 pm

Re: Help with this logical reasoning problem

Postby CardozoLaw09 » Tue Sep 18, 2012 12:07 pm

.
Last edited by CardozoLaw09 on Tue Jan 27, 2015 1:06 am, edited 1 time in total.

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TripTrip
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Joined: Fri Sep 07, 2012 9:52 am

Re: Help with this logical reasoning problem

Postby TripTrip » Wed Sep 19, 2012 10:48 pm

Cardozo - you have the idea right, but I think you could be a little more consistent with your variable definitions:

T: Liking Turnips
P: Liking Potatoes
Ex: Existential/Example/One Instance of

Ex(T & -P) thus -(P -> T)
When it is meant to be -(T -> P)
"It is not true that whoever likes turnips like potatoes."

_____________

N: Being a novel
P: Having 75 pages
Ex: Existential/Example/One Instance of

Ex(P & -N) thus -(N -> P)
When it is meant to be -(P -> N)
"It is not the case that everything over 75 pages is a novel."




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