Q25 - The police department

[ohthatpatrick]

Question Type:
Match the Flaw

Stimulus Breakdown:
Conclusion: F must be the burglar.
Evidence: Two suspects for the burglary: S and F, and S has an ironclad alibi (it wasn't S).

Answer Anticipation:
It's a valid argument to say
X is either A or B. X is not A.
Thus, X is B.

So we have to figure out how this burglary argument is different because we know it's a flawed argument. In the example I just wrote, the conclusion "X is B" would translate into "the burglar is Foster".

Does saying "S has an ironclad alibi" give us "S is not the burglar"? Seemingly. So the premise "X is not A", or "the burglar is not Schaeffer" seems to be valid.

The problem appears to be with the initial premise: "X is either A or B."
Does the argument actually say "The burglar must be Schaeffer or Forster"

No. We're told that S and F are both suspects, but we're not told they're the ONLY two options for burglars.

So the flaw is really "How do we know that S and F are the only two options?"

Correct Answer:
D

Answer Choice Analysis:
(A) "2 possible options. One of them probably will happen. Thus, the other won't.

That's a different argument / flaw. It would look like this
A and B are two options for X
A is probably happening
Thus B is not happening.

This is a flaw of assuming that two things are mutually exclusive, when we were never told that.

(B) This conditional format immediately throws me off the scent. Keep looking.

(C) Again, conditionals?

(D) YES! 2 possible options. One of them isn't happening. Thus the other one is. Looks great!

(E) "THE ONLY" two options. Wrong. In order to replicate the flaw, I need to hear about two things that might NOT be the only two options.

Takeaway/Pattern: In the original argument, we would have said
"Sure, Schaeffer isn't the burglar, but how can you be sure it's Forster? Maybe there are OTHER possible suspects you haven't found/discussed."

In (D) we would say
"Sure, Baxim isn't moving to Evansville, but how can you be sure they'll go to Rivertown? Maybe there are OTHER possible locations for moving headquarters that they haven't found/discussed."

#officialexplanation

[contropositive]

I looked at the degree of the conclusion, "must be", and eliminated B,C, E because it did not contain certainty language.
The flaw is the lack of evidence as to why F would be a burglar. I noticed it was talking about suspects then jumped to conclusion about burglar

What is the difference between A and D?
A is saying there is two possibilities. One will happen therefore the other is not happening. Is the problem "might" in the premise?

[DavidH327]

I think the difference between A and D is:
A's building a new primate house and refurbishing isn't necessarily an either..or relationship; rather it could be both.
Whereas, answer choice (D)'s moving headquarters to Evansville and moving to Rivertown implies either..or.. but not both.
Because you can't really have two headquarters in two different cities.

I also came down to A and D and this was my understanding to eliminate A.
Please correct me if I missed something!