Diagramming question

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sdwarrior403

Posts: 114
Joined: Fri Aug 10, 2012 8:13 pm

Diagramming question

It is typically on assumption type questions where this problem comes up for me.

For example, pretend that the conclusion of the argument is that A is the same as B.

Should I present this as...

A = B

A ----->B

A<----->B

TripTrip

Posts: 2762
Joined: Fri Sep 07, 2012 9:52 am

Re: Diagramming question

Don't use A -> B, because it implies that there could be some B that is not A. Either of the other two work. Personally I'd use = because it is easier to understand quickly.

Also, make sure you denote that it is the conclusion. Something like "Thus" or, if you're into formal propositional symbolism, "|-". I'm not sure if you do or don't based on the above, but it always helps me.

Zensack

Posts: 125
Joined: Tue Sep 04, 2012 10:05 pm

Re: Diagramming question

I would use "A = B" personally. I only use arrows for if/then type statements.

bp shinners

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Joined: Wed Mar 16, 2011 7:05 pm

Re: Diagramming question

Zensack wrote:I would use "A = B" personally. I only use arrows for if/then type statements.

I use the equals sign too. I also expect that the question will rely on me substituting those two terms at some point (though that's less likely when the equality is posited in the conclusion than in a premise).

05062014

Posts: 432
Joined: Fri Jul 06, 2012 11:05 pm

Re: Diagramming question

bp shinners wrote:
Zensack wrote:I would use "A = B" personally. I only use arrows for if/then type statements.

I use the equals sign too. I also expect that the question will rely on me substituting those two terms at some point (though that's less likely when the equality is posited in the conclusion than in a premise).

Are you referring to that damn beauty is truth question on pt 49? Is part of LR knowing when to substitute terms on both Suff and Nec conditions?

Zensack

Posts: 125
Joined: Tue Sep 04, 2012 10:05 pm

Re: Diagramming question

abdistotle wrote:
Are you referring to that damn beauty is truth question on pt 49? Is part of LR knowing when to substitute terms on both Suff and Nec conditions?

I'm not sure I understand your terminology, but my kneejerk reaction is no. LR is about spotting assumptions, making points/counter points, and identifying trains of logic. Parallel reasoning questions are the only LR questions I would use notation to work.

bp shinners

Posts: 3086
Joined: Wed Mar 16, 2011 7:05 pm

Re: Diagramming question

Zensack wrote:
abdistotle wrote:
Are you referring to that damn beauty is truth question on pt 49? Is part of LR knowing when to substitute terms on both Suff and Nec conditions?

I'm not sure I understand your terminology, but my kneejerk reaction is no. LR is about spotting assumptions, making points/counter points, and identifying trains of logic. Parallel reasoning questions are the only LR questions I would use notation to work.

It's also about avoiding equivocation. However, when the argument itself defines two terms as being equivalent, you can usually bet on the answer using the equivalent idea that isn't in the conclusion to try to throw you off. This usually happens in the philosophy of life questions (truth/beauty/happiness/trust/etc...). So I don't know if the specific beauty passage in question uses this trick, but I can think of at least one beauty passage that does.