Thomas: The club president had no right to disallow Jeffrey's vote. Club rules say that only members in good standing...

Naz May 26, 2015

The rule is that "only members in good standing may vote."

Meaning: if they can vote, then they are members in good standing

P1: V ==> MGS
not MGS ==> not V

"All members whose dues are fully paid are members in good standing."

P2: DFP ==> MGS
not MGS ==> not DFP

"Jeffrey has always paid his dues on time."

P3: DFP

So, we know since Jeffrey has always paid his dues on time, that--according to P2--he is a member in good standing. However, you can see from P1 that being a MGS does not mean you can necessarily vote. "MGS" is the necessary condition of P1. And, we know that we cannot infer anything else from a necessary condition.

Answer choice (A) is correct because the issue here is not that he is forbidden to vote by the rule, i.e. that he is prohibited, but he may still not be allowed to vote for some other unstated reason. There is a difference between not being prohibited to vote and being authorized to vote. Not being prohibited means that one is not formally forbidden by a rule, being authorized means having approval.

So, think about it this way: since he is in good standing, he is not prohibited from voting. But, just because he is in good standing does not mean he is authorized to vote. There could be some tertiary reason as to why he has been disallowed to vote. If you look at the necessary conditions of P1 and its contrapositive, we see that Jeffrey can be in good standing but also not be allowed to vote.

Hope that clears things up! Please let us know if you have any other questions.

Richmond June 7, 2018

C seems like a very similar answer. Can you explain why it is incorrect?

Christopher June 8, 2018

(C) doesn't strike at the heart of the logic in the question. Thomas claims that Jeffrey's vote should have counted because he is a member who is in good standing and "only members in good standing can vote." In doing so, he's missing that "only members can vote" does not mean "all members can vote."

The answer above gives you the explanation for why (A) is right, but (C) is wrong because it doesn't deal with the flaw. The truth of a statement is not at issue, so the assumption listed in (C) doesn't impact the argument at all.

Does that help?

Anthony-Resendes October 21, 2020

See when I finished reading the stimulus I did have the answer in my head. The answer being, although he was in good standing by paying his dues, there may be some other reason why he cannot vote. A is a very abstract answer choice, I'm still trying to understand how A says, "he may have paid his dues but that does not mean there isn't some other reason he may not be allowed to vote. Please help!

Victoria November 13, 2020

HI @Anthony-Resendes,

Happy to help! I agree that this wording is a bit confusing!

We know that the club rules say that "only members in good standing may vote." We know that "only" introduces a necessary condition. Therefore, if you can vote, you must be in good standing.

V --> GS
Not GS --> Not V

We also know that "all members whose dues are fully paid are in good standing."

MDFP --> GS
Not GS --> Not MDFP

So, based on the fact that Jeffrey is in good standing as a result of having paid his dues on time, we know that he is not prohibited from voting. However, this does not necessarily mean that he is authorized to vote. Just because Jeffrey is not prohibited from voting because he is in good standing does not mean that, overall, he is authorized to vote.

Therefore, Thomas fails to account for this distinction.

Hope this helps! Please let us know if you have any further questions.