Q22 - On Saturday Melvin suggested

[magnusgan]

Could someone please explain why (C) is not valid?

Is it because whether the vacation was scheduled of not is not the issue, rather the reasoning that Melvin uses to discredit Jerome's excuses?

Melvin's reasoning:
When someone repeatedly gives the same excuse --> must be lying

Since the stimulus does not give us any evidence to verify whether or not Jerome is lying or not, we can't jump to Melvin's conclusion which is "must be lying."

[ohthatpatrick]

I think you nailed the argument core, although it's not Melvin's reasoning, it's just the author's.

PREM -------------------------------> CONC
Makes the same excuse every time --> cost isn't the real reason

To fight this argument or show why it's flawed, we can temporarily adopt the OPPOSITE of the conclusion. Let's try to argue that cost IS the real reason.

If so, then why does Jerome make the same excuse every time?

I might say, maybe Jerome is always on a tight budget and all the trips Melvin proposes go beyond Jerome's budget.

Those are objections.

Assumptions would sound like the opposite of that
- Jerome ISN'T always on a tight budget
- Melvin DOESN'T always propose trips that go beyond Jerome's budget

To me, (C) sounds more like something that would strengthen the argument.

If Jerome really likes scheduled vacations more than unscheduled ones, then THAT'S the reason he keeps turning Melvin down.

That means the conclusion was correct: Cost is NOT the real reason.

But when Flaw answer choices start out with "fails to consider"/"overlooks the possibility", etc., the answer choice will only be correct if the idea that follows weakens.

Since (C) strengthens, we have to eliminate it.

=== other answers ===
(A) There is no attack on Melvin to forestall.

(B) Would it Weaken this argument if it were true that Melvin can't afford to take this vacation either? No. Melvin's budget is out of scope. We're only trying to evaluate whether Jerome is consistently turning down vacations because his budget is too tight or whether there is some other reason.

(D) This answer gives us Necessary Assumption language. Does the argument have to assume that "X is not the only excuse someone gives --> X is not a real excuse"?

Close, but no.

The argument assumes
"X is the only excuse someone gives (over and over) --> X is not a real excuse".

(E) "Does not examine the possibility" is Weaken language, so we ask ourselves, if it's true that "Jerome's behavior is adequately explained by the reason he gives for it", does that Weaken the argument?

Sure! This is just saying, "the author fails to consider that Jerome is actually telling the truth, he's really broke, and so he can never afford to take one of these vacations."

Let me know if you're unclear about any of this.