## #26 - Some eloquent speakers impress their audiences with

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Please post below with any questions!
ChicaRosa
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I was stuck with this problem and ended up choosing A instead of E and I would like to know why E is correct? I tried doing the problem in my head with the diagramming techniques but I got even more confused.

Is A wrong because it's comparing a general trait that a culture should have with a particular culture instead of two different cultures from one another?

The diagram of the stimulus would look like this:

ES= Eloquent Speaker
IA= Impress audience
O=Obscenity

Premise 1: ES IA
premise 2: O ES
Conclusion: O IA

So if E was diagrammed it would look like this:

S= Sculptors
M= Musicians
SWA= Significant works of art
Premise 1: S SWA
Premise 2: M S
Conclusion: M SWA

I hope I diagrammed it correctly.

Thanks!
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David Boyle
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ChicaRosa wrote:I was stuck with this problem and ended up choosing A instead of E and I would like to know why E is correct? I tried doing the problem in my head with the diagramming techniques but I got even more confused.

Is A wrong because it's comparing a general trait that a culture should have with a particular culture instead of two different cultures from one another?

The diagram of the stimulus would look like this:

ES= Eloquent Speaker
IA= Impress audience
O=Obscenity

Premise 1: ES IA
premise 2: O ES
Conclusion: O IA

So if E was diagrammed it would look like this:

S= Sculptors
M= Musicians
SWA= Significant works of art
Premise 1: S SWA
Premise 2: M S
Conclusion: M SWA

I hope I diagrammed it correctly.

Thanks!

Hello,

As for "Is A wrong because it's comparing a general trait that a culture should have with a particular culture instead of two different cultures from one another?", no, not especially. Answer A is wrong because it's right, i.e., it's logically valid, being basically a Repeat form. (Slash myth slash fun. moral certainties; slash myth slash fun. moral certainties.)
As for the rest, the diagramming seems o.k., and is something of a Mistaken Negation, or close to it, with some "Formal Logic" thrown in.

David
jw190
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This problem was the only one I missed in this section. The some / all flaw didn't click with me until after looking up the answers. Thanks for the help Chica and David! It helps me to write out an explanation to myself for missed questions, so here's what I came up with. Feel free to critique!

Premise: Some eloquent speakers impress their audiences...

GES<-S->IA

Premise: Speakers who resort to obscenity are not genuinely eloquent...

RO > ~GES
GES > ~RO

Conclusion: none of these speakers (those who resort to obscenity / are not genuinely eloquent) impress their audiences...

RO > ~IA
IA > ~RO

(~GES > ~IA)
(IA > GES)

The premises do not add up to the conclusion. Just because SOME audiences are impressed with an eloquent speaker does NOT mean that if the audience was impressed, the speaker must have been genuinely eloquent.
________________________

A) Incorrect for two reasons. First, the conclusion is about a certain (some) culture, instead of a sweeping conclusion about all cultures. More importantly, the argument isn't even flawed:

Premise:

MC > MYTH
~MYTH > ~MC

Conclusion:

~MYTH > ~MC

Here, the conclusion is the contrapositive of the premise, and therefore not flawed.

B) Here, the conclusion is also about "some" authors, not "all" authors. Plus, this choice is not flawed. We know that SOME authors both write one page per day AND produce one page per year. Serious authors do not write one page per day. It is safe to conclude that SOME authors who write one book per year must not be serious; we know that because some authors do both (one page / day and one book / year) it stands to reason that at least one of that group must not be serious as they're NOT writing one page per day.

C) The formal logic in this choice is very different from the stimulus. The first premise is an "all" statement, and the conclusion is a "some" statement, both unlike the stimulus. This choice is flawed though. We know if a place is a center of commerce, it must be a center of industry. But this is not to say that if a place is a center of industry, it must be a center of commerce! Therefore, it could be that all centers of commerce are large; all of those large centers of commerce would also be large centers of industry. But a place could be a center of industry without being a center of commerce, so the size of that center of industry is completely independent.

D) The conclusion here uses the word "probably." That's very far off from the definite conclusion we're trying to match.

E) This choice does match the "all" conclusion from the stimulus.

Premise: Sculptors sometimes produce significant works of art...

SCUPLT <-S-> SWA

Premise: Musicians are not sculptors...

MUSC > ~SCULPT
SCULPT > ~MUSC

Conclusion: Musicians (not a sculptor) never produce significant works of art...

MUSC > ~SWA
SWA > ~MUSC

(~SCULPT > ~SWA)
(SWA > SCULPT)

Similar to the stimulus, the argument assumes that if you produce a significant work of art, you must be a sculptor (and if you're not a sculptor, you must not have produced a significant work of art). This assumption is incorrectly based off of the some statement from the first premise. Correct.
Last edited by jw190 on Thu Dec 22, 2016 7:40 pm, edited 1 time in total.
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Good analysis, jw! You got it, on nearly all counts I think. Well done! The only quibble I have is with your claim about the stimulus here:

Basically, the argument is taking a "some" statement, and using it to improperly make an "all" conclusion.

That's part of the problem, but not all of it. It's not just that he treats the claim as "All eloquent speakers impress their audience", but that he then also mistakenly reverses it to come out with "anyone who impresses their audience is an eloquent speaker."

Other than that, you are all over it my friend! Keep up the good work!
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jw190
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Adam Tyson wrote:Good analysis, jw! You got it, on nearly all counts I think. Well done! The only quibble I have is with your claim about the stimulus here:

Basically, the argument is taking a "some" statement, and using it to improperly make an "all" conclusion.

That's part of the problem, but not all of it. It's not just that he treats the claim as "All eloquent speakers impress their audience", but that he then also mistakenly reverses it to come out with "anyone who impresses their audience is an eloquent speaker."

Other than that, you are all over it my friend! Keep up the good work!

Thanks for that feedback and your kind words! I'll go ahead and remove that sentence incase anyone else struggled on this question.
deck1134
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Is this one that we should diagram? I got totally lost here. Usually, on parallel you can sort of "feel it out," but I had absolutely no idea what the flaw even was.
gcs4v333
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I don't understand the last step in this diagram.

jw190 wrote:
Premise: Some eloquent speakers impress their audiences...

GES<-S->IA

Premise: Speakers who resort to obscenity are not genuinely eloquent...

RO > ~GES
GES > ~RO

Conclusion: none of these speakers (those who resort to obscenity / are not genuinely eloquent) impress their audiences...

RO > ~IA
IA > ~RO

(~GES > ~IA)
(IA > GES)

If you have:
RO GES
RO IA

How do you then get GES IA? I thought you couldn't combine two conditionals when the common element is in both the sufficient or in both the necessary positions. So if you have A B and A C you couldn't necessarily conclude
B C.

Is the issue that this isn't conditional logic but formal logic? If so, how should I read his diagram so that I see how to come up with that conclusion? Thank you.
Brook Miscoski
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GCS,

The issue is not any difference between conditional reasoning and formal logic. Please take another look at the stimulus and question stem. Since it is a parallel the flaw question, all we are doing is diagramming what the stimulus actually says. Trying to understand the stimulus as a series of correct logical steps will lead to confusion, because the reasoning in the stimulus is, in fact, incorrect.