#26 - Researcher: The vast majority of a person’s dreams

[mcdonom4]

Hi Jon!

Thank you so much for your response! This definitely clears it up a bunch. I guess I couldn't find a specific "test" in the LR Bible because, at least in the 2017 version, it isn't presented that way, but I just went through and reread the entire chapter and the methods you described are definitely in there (pg. 515-519 for anyone wondering).

Parallel Reasoning and Parallel Flaw questions are definitely one of my weak spots for LRs, so this really helps! Thank you!

[nonowing]

Hi,

I am struggling to see why answer choice D (the credited response) is not a flawed argument. D states that it is unreasonable to conclude that aspirin is dangerous (based on evidence that a number of people prematurely die) because most people don't die. Most means more than half, and does not necessarily mean all or almost all. So, let's pretend that 49% of people died prematurely from aspirin -- does that give us evidence that it is not dangerous? I don't think so. The cutoff for "Dangerous medicine" is certainly not a 50% death rate.

On a parallel non-flawed reasoning question, can the right answer be flawed and correct? Or am I supposed to assume that "most" in this context means all/almost all? I understand from scientific studies and personal experience that aspirin as a drug is not dangerous -- but isn't that information outside knowledge?

[Jeff Wren]

Hi nonowing,

First, it is entirely possible that Parallel Reasoning questions can contain flawed logic in the stimulus even if the question stem does not mention that the logic is flawed, in which case the correct answer will also contain the exact same flawed logic. There are definitely examples of Parallel questions with clearly flawed logic even though the flawed reasoning is not mentioned in the question. Basically, if the question stem tells you it's flawed, then it is flawed, but if the question doesn't mention whether it's flawed, then you need to analyze the reasoning for yourself to determine whether or not it is flawed.

In that way, Parallel questions are similar to Method of Reasoning questions, which can also be flawed even though this isn't mentioned the question stem.

As far as Answer D, it's important to be very clear on what the conclusion is (and isn't) saying. The statement that "it is unreasonable to conclude that aspirin is dangerous" is not the same as definitively saying "aspirin is not dangerous."

What this conclusion is getting at is that based on the information given (a number of people who die prematurely take aspirin, which could be complete coincidence, but most people who take aspirin do not die prematurely), then there is no reason to conclude that aspirin is dangerous based on those facts. However, it is still possible that aspirin is in fact dangerous, but these facts don't prove it.

Here's a similar argument for illustration.

A number of people who die prematurely drink milk, but most people who drink milk do not die prematurely, so there is no reason to conclude that milk is dangerous based on those facts.

[nonowing]

Hi,

Thanks for your response.

I see how the conclusion is "it is unreasonable to conclude" that the drug is dangerous. But how is it unreasonable to conclude that aspirin is dangerous if it were true that 49% of people died from the drug? (In that case, it would be true that most people did not die from it, but it would still be rational to conclude that the drug is dangerous). To me, just because most people do not die from it does not make unreasonable a conclusion that the drug is dangerous.

No drug would ever be approved with a >50% death rate. So learning that the death rate is less than 50% doesn't really tell us anything about whether it is reasonable to conclude that it is dangerous.

[Rachael Wilkenfeld]

Hi nonowing,

You don't have those numbers here though. You just have that "a number" of people have died prematurely. We don't know if it's 1% or 49% of aspirin takers. So the information we have (consistent with both percentages) is not enough to let us know that aspirin is dangerous. It's possible that aspirin is dangerous---it's just that the information in the premise isn't enough to prove that it is.

It's important to remember that just because we don't have evidence to show something, doesn't mean it's not true. For example it would be unreasonable for you to conclude that it's sunny where I am right now. It's actually true that it is---but until I told you that, it would have been unreasonable for you to draw that conclusion.

Hope that helps!