40.3.17 (small question about the wrong answer choices)

Accounts Playable

I got this question correct, but I marked it for BR because I like analyzing parallel questions for practice. During BR, I am having a ton of trouble eliminating B.

Specifically, the flaw in the argument is your typical invalid argument form: A-->B. B. Therefore A. The argument invalidly uses the converse of the premise as the conclusion.

Answer choice A clearly does that, and this is the correct answer. However, doesn't answer choice B technically do this as well?

Here is my breakdown of B:
Discover something new-->Examined all possible solutions. Fran -Discover something new. Therefore, -Examine all possible solutions. This answer choice invalidly uses the inverse of the premise. Nevertheless, if you take the contrapositive of the conclusion, Examine all possible solutions-->Discover something new, isn't this logically identical to the flaw in the passage? In other words, am I misreading something in this answer choice, or is the "form" better than the "substance?"

Thanks.

c.janson35

It's a very similar flaw, but the one in the stimulus is an incorrect reversal (mixing up suff and nec) while the one in answer choice B is an incorrect negation (taking the absence of the suff as proof of the absence of the nec).

Your template for the stim is perfect, so compare it to how B is diagrammed:

DSN-->EAS
/DSN
------------------------
/EAS

This is a different logical flaw than:
A-->B
B
--------------
A

NewEnglandBound

I'll take a crack (warning: I'm using "!" to mean "not"):

As you says this flaw is:
A -> B
B
___________
A

What's the flaw in B?
If you have discovered something new (DSN), then you have examined all possibilities (EAP).
DSN->EAP
Fran has NEVER discovered something new (!DSN). Therefore Fran has never explored all possibilities (!EAP).

So the flaw here is:
A->B
!A
__________
!B

I think your issue may be with the "therefore" in answer B. As it's not saying !DSN->!EAP, it's saying:
!DSN
_______
!EAP

Does this follow for you? I admit that I'm possibly wrong, but that's the way I see it.

Accounts Playable

Thanks, guys. I see it. I think I drank a little too much coffee this morning, and I overthought this during BR haha