#3 - A study of the dietary habits of a group of people who

[Adam Tyson]

Answer A is certainly the most attractive wrong answer here, Mariam, as can by seen by how many students in this thread continue to ask about it! While that answer does open up the possibility of some alternate cause, it does so in a very weak way, because it doesn't actually point to any particular alternate cause, and because it doesn't do much (if anything) to address the correlation between low levels of the enzyme and the incidence of cancer.

Here's another way to think about it: even if the diets of the people in the study were not all identical in every way, would that harm the argument? Would our author say "oops, wow, I failed to consider that, my bad, never mind my conclusion now"? Or would the author say "sure, diets vary from person to person, both within each group and across the two groups, but when we compared yogurt intake and galactose levels with enzyme levels we saw a very clear correlation between those who had low enzyme levels and those who developed cancer, so we stand by our conclusion." The correct answer to a Flaw question has to do more than just be a true statement. It also has to be something that is a real problem for the argument, one where the author might just hang their head in shame for having made such a grievous error.

Bear in mind that the answer does not say that the diet of one group had differences when compared to the other group. If the cancer group had consumed a lot more Peanut butter than the non-cancer group, for example, that might be an alternate cause. But this answer isn't showing us a difference between groups, but between individuals in those groups.

[lemonade42]

Hello,

I have a question about why (C) is wrong.
The book says that the central assumption of basic causal conclusions is that the "speaker assumes that the stated cause is the only possible cause of the effect and will always cause the effect". So doesn't that mean we should assume the author thinks that galactose is the only cause of cancer because the conclusion is a causal conclusion. But, a previous response to this question, said we shouldn't assume that. Wouldn't that be going against what the book said?

My original thought when reading the stimulus was that the author doesn't specifically suggest they think that galactose is the only cause. But then I remembered the book saying the central assumption IS to think they assume it's the only cause. So now I'm confused on how to determine why C is wrong.

[Chandler H]

Hello,

I have a question about why (C) is wrong.
The book says that the central assumption of basic causal conclusions is that the "speaker assumes that the stated cause is the only possible cause of the effect and will always cause the effect". So doesn't that mean we should assume the author thinks that galactose is the only cause of cancer because the conclusion is a causal conclusion. But, a previous response to this question, said we shouldn't assume that. Wouldn't that be going against what the book said?

My original thought when reading the stimulus was that the author doesn't specifically suggest they think that galactose is the only cause. But then I remembered the book saying the central assumption IS to think they assume it's the only cause. So now I'm confused on how to determine why C is wrong.

Hi lemonade42,

Good question! The quote from the book is referring to causal conclusions that are as straightforward as "Therefore, X causes Y." This sentence is very different from the sentence "Therefore, X is a cause of Y." The first sentence implies that Y is always preceded by X; the second just tells us it's possible that Y is preceded by X.

In this stimulus, the author argues that galactose is "carcinogenic," which simply means that it is a possible cause of cancer. Therefore, the argument is simply over whether or not galactose could possibly cause cancer, not over whether or not it's the ONLY thing that causes cancer.

[sean.reilly]

I have a question on answer choice D. This was one of my final two contenders but I eliminated it because I thought the time-sequence established in the stimulus precluded the possibility that cancer caused the galactose deficiency.

Specifically, the stimulus states that the study focused on "a group of people who has RECENTLY developed cancer" - I took this to mean that the cancer appeared recently relative to the present moment ie over the course of the five-year study. Thus, the low levels of galactose enzyme identified over the course of the study must have PRECEDED the development of cancer. For this reason, I eliminated D.

Did the stimulus actually mean that the cancer appeared shortly before those individuals were selected for the study, ie they had cancer from the beginning of the five-year period? In which case I agree, D becomes the most attractive answer choice.

[Luke Haqq]

Hi sean.reilly!

In short, as I understand the stimulus, the answer to your question is yes. The cancer appeared before the people were selected for the study. Indeed, the study seemed to select one group with cancer and one group without it. There's nothing in the stimulus that requires the word "recently" to mean sometime during the five-year study.