P: A–some–CP: ?C: not Z–some–A

acexviii December 19 at 04:22PM

Confusion

I put Not Z —> C because I saw A-some-C, so C-some-A Not Z —> some- A Not Z —> C —> some A Where is my flaw in logic and how can i fix it?

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Austin1 August 14 at 10:03PM

I have this same question after reaching the same conclusion. In the Q: P1=A-some-C [C-some-A]; P2=?; and, C=not Z-some-A. I the qualifier rule is that qualifiers do not have contrapositives in the way that S->N statements do, and, as a result, P1 reverses in the way I diagram above, then why not Z->C incorrect, but C->not Z is correct? The explanation shows the chain as A-some-C->not Z. In order to reach the conclusion in the question, are you supposed to just read it backwards? If so, why is that allowed here with this chain when is explicitly not something allowed in S->N statements? Moreover, if all you do with quantifiers is reverse them, wouldn't NotZ->C-some-A also be a correct arrangement? If not, why? And if that reversal is correct, then why isn't it correct?

Following the rules that the courses teach, I genuinely do not understand why it is ok here to go backwards through an "->" when it isn't something you can do normally.

Also, there is still a typo in the answer explanation per @Raechel-Brodsky on May 29, 2020. The answer explanation says: "C=NotZ-some-A [notA-some-notZ]" that is the same typo Raechel identified five years ago...

Austin1 August 14 at 10:06PM

It won't let me post a screenshot of the answer expanation I see, but check the Android version of the app. That is where I see the typo I mention in my not (and I can provide a screenshot if someone needs it).