The one instance that would prove the show realistic would be if F and B were disabled. Thus, If F and B are disabled the show is realistic. This is my logic, please explain where I am mistaken.

Shane,

We've got an "only if" statement here, so let's do a little diagramming:

P 1: The Flintstones TV show would be realistic only if Fred and Barney were both be disabled
P 1: F Real → F/B Dis

P 2: Yet in every scene, both Fred and Barney do have feet.
P 2: ~(F/B Dis)

So if we take the CPos of Premise 1, we get: ~(F/B Dis) → ~(F Real).
And if we look at premise 2, you can see we have ~(F/B Dis).
Therefore, by the CPos of Premise 1, we have ~(F Real).

Shane,
I think you've got the right idea, but let's make it clear in case anybody else has questions about this.

Let's say we've got the following statement:
"If we have X, then we must also have Y."

This can be diagrammed: "X → Y"

This means that whenever we have X, we MUST also have Y.
Think of it like this: X will always CAUSE Y to occur.

Now, what if we also have the statement:
"We know for certain we don't have Y."

This can be diagrammed: "~Y"

So what can we conclude given "X → Y" -and- "~Y"?

Well, we can infer that we must NOT have X, because X ALWAYS causes Y, and we know we don't have Y.


What about this scenario: "X → Y" -and- "~X"

What can we infer here? The answer is absolutely nuthin'. It is possible that we have Y, and it is possible that we do NOT have Y. We can't draw any conclusion about Y.

NOTE 1:
You can ALWAYS derive the "contrapositive" relationship from a conditional statement.
So if we have "X → Y", we also know we have "~Y → ~X."

NOTE 2:
You can NEVER simply "flip" a conditional around.
So just because we have "X → Y" does NOT mean we have "Y → X."

NOTE 3:
You can NEVER simply negate the terms of a conditional without reversing the order.
So just because we have "X → Y" does NOT mean we have "~X → ~Y."

I don't understand how "C" would not be correct. It states "the Flinstones would be realistic only if Fred and Barney were both disabled". "c" states "the Flinstones would be realistic if Fred and Barney were both disabled". That's exactly what the question states the only thing that would make the Flinstones realistic, so I fail to see how that answer is wrong.