Q5 - Byrne: One of our club's bylaws specifies

[demetri.blaisdell]

Thanks for your question. This is a great problem to test the difference between sufficient and necessary conditions. If we cut through the clutter, the argument core is:

Being late for quarterly meeting or missing 2 monthly meetings gets you suspended + T didn't miss any meetings -----> T must have been late for quarterly meeting

Maybe an analogy will help show why this is flawed:

Rule: if you cheat on your exam or help anyone cheat, you will receive an F.

T didn't cheat but he got an F ----> T must have helped someone cheat

But couldn't T have never turned in homework and failed the midterm?

So the flaw here is confusing a sufficient condition (two different ways to get suspended) with a sufficient and necessary condition (the only two ways to get suspended).

(B) tells us that. The argument assumes that a sufficient condition is the only sufficient condition.

The wrong answers:

(A) is out of scope. Arriving late for the monthly meetings doesn't have consequences, as far as we know from the stimulus.

(C) is backwards. The argument is not confusing the necessary for the sufficient. That would look like this:

Before you receive an F, you must have a meeting with the dean. T had a meeting with the dean. Therefore, T must have received an F.

The problem in my example is confusing a necessary condition (the meeting) with a sufficient condition (something that guarantees an F). But the stimulus is confusing what is sufficient for what is necessary.

(D) is obviously out of scope. The logic doesn't require a precise definition of late.

(E) is even further out of scope. There's no reason why the length of his tenure would be relevant.

I hope this explanation helps. Let me know if you have any more questions.

Demetri


#officialexplanation

[jardinsouslapluie5]

Why is (C) wrong?

[joseph.m.kirby]

This problem boils down to:

FAQM: fails to appear for quarterly meeting
M2GM: misses 2 monthly general meetings
S: Suspended
Tbx: Thibodeaux

FAQM | M2GM --> S
S
~M2GM
-----------
FAQM


So, we know that Tbx was suspended and he did not miss any general meetings. From this, the conclusion is that Tbx failed to appear for quarterly meetings. This argument assumes that NO OTHER CONDITION is sufficient to result in suspension (the argument assumes only two conditions are sufficient). The flaw is noted in (B).

If the argument was limited to only including FAQM and S variables and the argument put forward:

FAQM --> S
S
-----
FAQM

Then (C) would be correct. The argument takes for granted that an assumption required to establish the argument's conclusion (S --> FAQM) is sufficient to establish this conclusion. Notice it's an assumption because it's not stated. It's sufficient because it would lead to the logical drawing of the conclusion (FAQM). It's a flaw, however, in that it's a mistaken reversal of one of the premises.

[hnadgauda]

I didn't understand the explanations written above. To me it seems like the flaw in the argument is illegal reversal.

Our stimulus tells us:

~on time or miss 2 meetings --> suspended
suspended + ~miss meetings
---
~on time

The above would be satisfied if the illegal reversal was true:

suspended --> ~on time or miss 2 meetings

I don't really understand what B is saying. What kind of flaw is B describing?
I thought C was describing an illegal reversal and that is why I chose it. Can you please explain what kinds of flaws B and C are describing and if my analysis of the stimulus is correct?

[Jayh507]

Taking a stab at question analysis-

Q#5 Argument Flaw: Find the Flaw

Conclusion: T must have failed to appear on time to meeting
Premise: Fail to appear on time for mtg OR misses 2 monthly meeting -> suspended
Premise 2: T was recently suspended
Premise 3: T has not missed a mtg
Gap: Assumes there is no other reason that someone could be suspended. Suspension is a necessary condition, not a sufficient.

A.) Incorrect- confuses the “misses 2 monthly meetings” but more importantly doesn’t address the gap
B.) Correct- if certain events (being late or missing meetings) produce a result (suspension), then no other event is sufficient to produce that result. Translation: assumes nothing else can lead to suspension. Great answer but then you read C and become tempted….
C.) This is tempting because is seems to hint at the necessary/sufficient confusion going on but if you dissect it, it’s not happening in the argument. The assumption required to establish the argument’s conclusion is that only those two factors lead to a suspension, if we assume those 2 factors are sufficient to establish the conclusion, it’s just saying what we already know. The issue is suspension is being treating like a sufficient condition of the 2 factors.
D.) Completely irrelevant
E.) Not relevant

[SJK493]

(C) is backwards. The argument is not confusing the necessary for the sufficient. That would look like this:

Before you receive an F, you must have a meeting with the dean. T had a meeting with the dean. Therefore, T must have received an F.

The problem in my example is confusing a necessary condition (the meeting) with a sufficient condition (something that guarantees an F). But the stimulus is confusing what is sufficient for what is necessary.


#officialexplanation

I would like to clarify why answer (C) is incorrect. The argument does in fact confuse a necessary condition (suspension) with a sufficient condition because it states that because the officer was recently suspended and never missed a monthly meeting, he was late to the quarterly meeting. It reverses the conditional statements around.

Can anyone give an extended explanation for this?

[obobob]

Hi, I also need additional help with understanding the answer choice (C) and what kind of case could have made (C) the correct answer.

[ohthatpatrick]

I don't think what this answer describes ever has happened or ever will happen.

It's not a Necessary vs. Sufficient answer in the normal sense, which would say "the author confuses something necessary with something sufficient".

This adds a weird layer of "Assuming an assumption".
Takes for granted = assumes

(C) Assumes that an assumption req'd for conclusion is suff for conc

So to make an argument that matches, you'd need an explicit nec assumption, and the author would have to act like that idea would prove the conclusion.

EXAMPLE:
No one knows where Jake is. Some people think he took a one-person kayak out to the island, but for that to be true, he would have to know how to use a one-person kayak. Therefore, if Jake does know how to use a one-person kayak, then he clearly took a one-person kayak out to the island.