#14 - Investigators have not proved that the forest fire was

[Dave Killoran]

Hi Amy,

Whenever you encounter a situation like this, you can rely on the test makers not to lie to you in the question stem. When they say it's flawed, then it will be. That can help as a starting point since you then know there is an error present. There will be times you won't see the error on your first read-through, but then a question stem like this lets you know you stop and go back to find it.

The error here is that because two individual causes have not yet been separately proved, the author then concludes that the entire exercise hasn't been limited down to just those two causes. While those sound like similar things, they actually aren't.

To help see this error, let's put it in terms that are perhaps more relatable:

• Imagine that Oregon and Iowa State are playing a football game. We know that one will win.
  
  Let's then say that I haven't proven that Oregon won, and I haven't proven that Iowa State won. Does that mean that I haven't proven that Oregon or Iowa State won? No, primarily because in this case there will be a winner from one of those two. What's happened is I just haven't yet established which exact team won, but I do know that one of the two will win.

It's very tricky, but they move from individual explanations to collective, and that's the error. There's no contradicting of facts along the way, either.

Another way of thinking about it is: perhaps the investigators narrowed it down to one of these two causes, but they don't know which one it is yet. Does that somehow mean they didn't narrow it down? No.

Thanks!

[amys45]

Hi Dave,

That makes a lot of sense. Thank you for the clarification!

[lemonade42]

Hello,

I have a question about quickly eliminating answers. In general, if the stimulus doesn't include terms like "some" and "most", does that mean our answer choices should also not include "some" and "most". Therefore, if we were to scan through the answers, we can eliminate (C) and (D) immediately.

Also, can you check my understanding of (E). (E) is kind of saying (possible + possible = both are possible) while the stimulus is saying (not possible + not possible = both are not possible). But the presence of "not" term is not really the issue, because we shouldn't eliminate an answer just because of a negative term. Instead, the flaw is more about how the author in the stimulus ignored the possibility that one of the causes had to be the cause. And mistakenly concluded that none of them were the cause. But (E) is not ignoring the possibility that one of the causes had to be the cause. He is just mistakenly thinking both are in effect.

[Chandler H]

Hello,

I have a question about quickly eliminating answers. In general, if the stimulus doesn't include terms like "some" and "most", does that mean our answer choices should also not include "some" and "most". Therefore, if we were to scan through the answers, we can eliminate (C) and (D) immediately.

Also, can you check my understanding of (E). (E) is kind of saying (possible + possible = both are possible) while the stimulus is saying (not possible + not possible = both are not possible). But the presence of "not" term is not really the issue, because we shouldn't eliminate an answer just because of a negative term. Instead, the flaw is more about how the author in the stimulus ignored the possibility that one of the causes had to be the cause. And mistakenly concluded that none of them were the cause. But (E) is not ignoring the possibility that one of the causes had to be the cause. He is just mistakenly thinking both are in effect.

Hi, lemonade42,

Be careful! "Some" and "most" are certainly words to be aware of, but it's not always correct to immediately cross out any answer that doesn't match the stimulus. The test-makers are aware of tricks like that, and will try to subvert them. Those words can be cause for suspicion, but especially with Method of Reasoning questions, it's best to read each answer choice through.

As for answer choice (E)—your understanding of it is mostly correct. However, with MoR questions, it's also good to be suspicious of answers that invert the positive/negative terms from the stimulus, even though it's not a reason to throw out an answer choice immediately.