by civnetn Sun Jul 03, 2016 4:59 pm
I know this thread is like 3 years old but I'm drilling Necessary Assumption questions because they give me such a hard time.
I don't think I agree with all this discussion on variations in wording. In my humble opinion, it completely misses the mark.
It's interesting to me, because this is one instance where the negation technique doesn't work perfectly. Upon first inspection C) and D) are both correct. But when you delve further into the logical structure of the answer choices, this just isn't the case.
In order for the conclusion to be valid, it must be assumed that C) the number of airline crashes will decrease if pilot training programs focus on increasing actual flying time. Because if we negate this statement, the argument falls apart.
And here's where the negation test can fail you. Because, while C) is true, and in fact must be true for the argument to be valid, the only way for C) to be true is if increasing actual flying time will decrease pilot error (which contributes to 2/3rd's of commercial crashes). If increasing actually flying time doesn't decrease pilot error, than it can't possible stop planes from falling out of the sky. In other words, C) is ASSUMING D).
And that's when it dawned on me. I'm looking for a conditional. To be specific, a necessary condition. Conditions don't have assumptions. What does? Well, arguments have assumptions! BINGO.
Let's take a look at the logical structure of C) "the number of airline crashes will decrease IF pilot training programs focus on increasing actual flying time."
So you see our deceptive answer choice C) is actually a simple conditional chain. Not a mere condition. And conditional chains make assumptions all the time. Just like this one did. A correct assumption, but an assumption none-the-less.
Hence, D) "Lack of actual flying time is an important contributor to pilot error in commercial plane crashes," is correct.
While I HATE questions like these, because this took me much longer than I want to admit to figure out, I also LOVE them, because they teach you so much!
Look at what we can learn from this one question:
1.) Conditions can't have assumptions in them. Conditional chains, of course, can.
2.) The Negation Test can be misleading sometimes. In order to correct apply the technique, you MUST be certain of the logical structure you are applying the technique to. You can produce a false positive by negating a conditional chain!
3.) Pay close attention to sufficient indicators like IF. There's a tendency to read the question stem, realize you're dealing with a necessary assumption question and then pay no attention to sufficient modifiers. This is what the test makers were counting on!