Weakening Questions

monica123

I read the following (I think on one of the Manhattan prep forums) about weakening questions.

On weakening questions, when the argument posits a causal relationship, we seek an answer choice that does one of the following three things.

1. Provides an alternative cause
2. Provides an example of the presumed cause without the presumed effect
3. Provides an example of the presumed effect without the presumed cause.

I don't understand why/how 3 would weaken the argument, unless we are also assuming that if A causes B, then A is the ONLY thing that would cause B (i.e. A is necessary for

Can someone elaborate on this?

Also, on "most seriously weaken" questions, is it correct to think there will really be only one answer choice that weakens the argument? I am asking because of questions 21, section 1, on PT 79. Both answer choice A and E weaken the argumnet (According to the above), but E is clearly better.

Sami

Hey,

So I have not done PT 79. But I can explain why #3 would be considered a weakening answer in a causal relationship stimulus. And this is not because A is the only thing that causes B but because if B is occurring without A, it makes it a little more likely that A is not the cause of B.

For weakening questions we are not trying to weaken a stimulus 100%. Even if we weaken a stimulus by 1%, its still a weakening the stimulus technically. So if B occurs without A, it makes it slightly more likely that A does not cause B, not by much as you pointed out because there could be other causes for B, but it still makes it a little bit less likely so our stimulus is not as strong as before.

monica123

@"Sam Harris" thanks, that does make sense! I understand the concept of B occurring without A weakening the argument just "a little", but what confuses me is when there is a better answer choice available.

I know you haven't done PT 79 yet, but amongst the answer choices were 2 options
1. effect w/o cause
2. (In my opinion better) A does not cause B, but rather B causes A

Is it possible to have 2 answer choices that could conceivably weaken the argument? I was under the assumption this whole time that there would only be one.

Sami

@monica123 as far as I know there is usually only one correct answer choices. Sometime an answer choice will have a word that makes it close but disqualifies it.

I am going to tag someone here who I know has done PT 79. @bjphillips5 Can you help out with this one?

Or @"Cant Get Right"

monica123

@Sami thanks for your help

@"Cant Get Right" or @bjphillips5 if you could that a look, that would be really helpful! This question is driving me crazy haha.

monica123

@"Dillon A. Wright" if you could get someone to take a look a this question for me that would be really helpful.

Cant Get Right

Well it looks like you definitely got the right answer. Answer choice E does exactly what you say and it's actually pretty devastating to the argument. I don't see anything else that affects the argument though. Which answer choice are you calling effect without cause? A? If you're looking at A, this doesn't weaken because the argument is only concerned with the subset of patients who show high levels of whatever-it's-called. It's fine if there are other subsets of patients, we're just only concerned with this particular one.