#18 - Medical researcher: A survey of more than 1 million

[Adam Tyson]

Right, Laurie! It's not about taking evidence of a causal relationship and assuming it is the only cause (answer B), but taking a correlation and assuming it is causal in a specific way (instead of perhaps an alternate or reversed causal relationship) (answer A). Nicely done!

[dandelionsroar]

Hi, I understand why A works but I still don't understand why D couldn't. While I can see now how it reverses the premise and conclusion in the stimulus, in this instance wouldn't that be ok? While the researcher doesn't say it, wouldn't answer D be an implicit assumption to his conclusion?

My understanding is that he takes for granted a causation between two phenomena if there is a correlation between the two. Or is it a mistaken reversal? Maybe the wording is confusing me.

Thanks for any help!

[Jeremy Press]

Hi dandelionsroar,

You're absolutely right that the author's assumption is this: "If there's a correlation between two phenomena, then there is a causal relationship between those phenomena," which, incidentally, is the classic "mistaking correlation for causation" flaw! We diagram it as such: Correlation Causation

And you're also correct that the way answer choice D is written is a mistaken reversal of that assumption: "If there's causation, then there's correlation." Causation Correlation (the mistaken reversal!).

Since an author is never required to assume the mistaken reversal of a conditional relationship that's part of his or her argument, answer choice D is inaccurate (the author is not necessarily taking that mistaken reversal relationship "for granted").

I hope this helps!

Jeremy

[caitlin3296]

I'm still confused as to why E is not the correct answer. I think I may be misunderstanding either the argument or the task of the question.

I thought the author's argument was "mild sleep deprivation is not unhealthy and, in fact, probably bolsters the body's defenses against illness." I specifically paid attention to the author saying that "mild sleep deprivation is not unhealthy." With this in mind, E looked like the correct answer because the author assumes that sleep deprivation is not unhealthy based on the findings of the study and fails to consider that the phenomenon may have other negative consequences and be unhealthy after all.

Can someone show me where I went wrong?

Thank you!

[Frank Peter]

HI Caitlin,

I would say that if a counter-argument here focused on "other negative consequences", that wouldn't be a counter-argument that seeks to prove that sleep deprivation actually is unhealthy. "Health" as a concept shows up pretty frequently on the LSAT, and by its nature it is a pretty broad concept. So if we are talking about "other negative consequences" it would have to be something outside of health - maybe perhaps there are financial consequences or interpersonal consequences. But since we are trying to show how the argument is most vulnerable to criticism, we should focus on attacking the argument on its own terms. (A) points to the biggest problem with this argument: the possibility that maybe it's not that sleeping more causes illness, but that illness is causing some to sleep longer.

[jmulder615]

I am happy to be proven wrong, but this seems like a question that has two possible correct answers. I obviously do understand why A is correct: this is a cut-and-dry causal flaw. However, I don't think E is necessarily incorrect. At the end of the day, this argument deals with what is "unhealthy." It would be a mistake to deduce that health is a binary question of illness vs. non-illness. For example, there could be a myriad of physical or mental consequences that could be unhealthy from sleep deprivation that would not constitute illness. This is, objectively, a part-to-whole flaw, in which the author takes one component of health at large, notices that it is not associated with something, and deduces that health generally has been secured. Of course, within that conclusion itself is a causal flaw, but the presence of a causal flaw doesn't eliminate the possibility that there are multiple flaws present. I have visited explanations for three different LSAT platforms, and none of them have given a super good explanation of why this is wrong. All explanations have limited health to the binary scale I discussed which just doesn't seem super appropriate or indicative of what health really means

[Jonathan Evans]

Hi, jmulder!

Good analysis!

You're right that health and illness are not necessarily a binary spectrum. However, answer choice (E) is not correct for several reasons.

The conclusion has two claims: (1) mild sleep deprivation is not unhealthy, i.e. mild sleep deprivation is either health neutral or healthy, and (2) mild sleep deprivation probably protects against illness.

We do this on the basis of an observed correlation.

This is a straight correlation to causation fallacy, which makes answer choice (A) the answer that describes why the argument is most vulnerable to criticism.

However, beyond the objectively more accurate answer choice (A), let's take a closer look at answer choice (E). The first part of answer choice (E) again describes this correlation or lack thereof between illness and mild sleep deprivation. This is fine. The breakdown occurs when you try to connect the second part of answer choice (E) to the conclusion.

With respect to the first part of the conclusion ((1) mild sleep deprivation is not unhealthy, i.e. mild sleep deprivation is either health neutral or healthy), even if mild sleep deprivation had other negative consequences, we cannot assume that these negative consequences are health related. For instance, the other negative consequences could be that you doze off at your job all day. We introduce our own unwarranted assumptions to try to connect answer choice (E) to the conclusion.

With respect to the second part of the conclusion ((2) mild sleep deprivation probably protects against illness), the inadequacy of answer choice (E) becomes even more apparent. The claim in the conclusion is about a causal relationship between mild sleep deprivation and incidence of illness. The second part of answer choice (E) is in no way a "shell game;" we are talking about illness in the premises, and in the second part of answer choice (E) we are still making a conclusion about illness. Any other "negative consequences" are not germane and do not describe this fallacy.

At best answer choice (E) could only be relevant to describing a flaw in the first part of the conclusion, and even there we have to introduce our own assumptions to make it work.

Therefore, answer choice (A) is the best answer.

I hope this helps!