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 KelseyWoods
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#71951
Hi Hanna!

The conclusion is that "long-term friends are probably of the same approximate age" so the characteristic that the author is inferring is present is "being the same approximate age" not "feeling comfortable approaching if the same age." Also the author does not infer that a characteristic is definitely present based on a premise that it's usually present--which is the flaw that answer choice (B) is describing. Instead, the conclusion says that the characteristic (being the same approximate age) is "probably" present. So our argument does not fit the flaw described by answer choice (B).

Hope this helps!

Best,
Kelsey
 hrhyoo
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#71978
Hi Kelsey,

Isn't "most" same as "probable"? B doesn't say definitely, it says "most."

Also, I have another question regarding formal logic:

This question is mistaken reversal because the stimulus states

A -> B
C -> B
THEREFORE C -> A

What if the argument was like the following:

A -> B
C -> B
Therefore A -> C

What kind of flaw is this?

Thank you always!


Hanna
 James Finch
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#71988
Hi Hanna,

To answer your questions, yes, "probable" in this case is the same as "most", as it means "more likely than not". As for your second scenario, when we have a chain issue where the stimulus gives us two conditional statements that share the same necessary condition but have different sufficient conditions, and tries to conclude one of the sufficient conditions is actually a necessary condition of the other sufficient condition, this is a form of mistaken reversal. It doesn't matter which of the two is chosen; for your scenario, it could be either either C or A, and it would still be the same logical fallacy committed, as both are essentially logically equal as sufficient conditions for the necessary condition B. Diagramming them together might clarify this:

Premises: C or A :most: B

Conclusion: C :most: A or A :most: C both share the same problem of trying to connect sufficient conditions in an invalid manner

Hope this clears things up!
 hrhyoo
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#72009
Thank you James! Could you also explain why B is incorrect?

H
 Zach Foreman
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#72039
hryoo,
Most fundamentally, it is incorrect because it doesn't fit our prephrase, "just because you are comfortable approaching same-aged strangers doesn't mean you must be UNCOMFORTABLE approaching different-aged strangers."
B can be paraphrased as "most things of this type have quality X therefore this thing has quality X". If that were applied here it would be something like "Most long term friendships are of similar age to one another. Therefore John's long term friend must be of similar age to him." But that is clearly not what is happening in this stimulus. Hope that helps.

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