Logical ReasoningDifficulty: Hard

PT127 S1 Q20 Explanation

A recent study suggests that

A free, expert breakdown of this official LSAT Logical Reasoning question.

TopicsFlaw

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Stimulus

A recent study suggests that consuming three glasses of wine daily substantially decreases the risk of stroke. Critics of the study, defending earlier research recommending one glass of wine daily, claim that binge drinkers (who drink once a week or less, but drink three or more drinks when they do drink) are with that level of consumption is negated by its associated increased risk of sudden heart attack.

What this question is testing

Flaw

Your task

Describe the reasoning error the argument actually commits.

Common trap

Answers that name a real logical flaw the argument doesn't actually make.

Winning move

Articulate the gap in the reasoning yourself, then match it to the choice that describes that gap.

Reading along? Open the full official question in LawHub — we show a fragment here and keep the reasoning in our own words.

The question
20.

The critics’ argument is most vulnerable to criticism on the grounds

Answer choices

  1. Correct70% picked this

    inappropriately attributes the consequences of binge drinking to persons whose regular consumption of wine is

    Why this is right

    The critics' premise is saying, "Sure, 3 glasses of wine a day would help decrease your risk of stroke. But it wouldn't benefit your health overall because you'd be more likely to die from sudden heart attacks." Where did it ever say that 3 glasses of wine increases your risk of sudden heart attacks? It didn't. It just said that binge drinkers have a higher risk of sudden heart attack (but not because they drink 3 glasses of wine daily). If the author is acting like "that level of consumption (3 wine / day) is associated with an increased risk of sudden heart attack", then he is attributing a consequence of binge drinking (higher risk of heart attack) to this separate plan of drinking 3 glasses of wine per day. They don't have anything to do with each other. Someone could drink 3 glasses of wine per day, and not binge drink, and they would presumably get the decreased risk of stroke without getting any increased risk of sudden heart attack. (Technically, the argument never said that the increased risk of heart attack was a consequence of binge drinking, so this answer is not perfect, but it's the best available and sounds the most like our complaint.)

    Skill tested: Flaw · how this choice captures the argument's function is the move to repeat next time.

  2. Doesn't Confuse Risks6% picked this

    confuses the risk of sudden alcohol-induced heart attacks with other

    The author isn't confusing one risk with another. He is comparing a decreased health risk (less chance of stroke) with an increased health risk (higher chance of sudden heart attack). He is definitely assuming that for someone who has both the decreased risk of stroke and the increased risk of heart attack, that the positive is completely offset by the negative, but he isn't confusing one type of risk with another.

  3. Too Strong: no difference7% picked this

    presumes, without providing justification, that there is no significant difference between wine and other alcoholic beverages in terms

    Since this answer begins with presumes / takes for granted / fails to establish, we can ask ourselves whether this answer truly is a Necessary Assumption. The critics don't need to assume that wine is not significantly different from other alcoholic beverages. They are fine with believing that wine is significantly different. In fact, their argument seems to acknowledge that wine does have special benefits (consuming 3 glasses a day can decrease the risk of stroke). The critics are merely saying that the benefit that wine drinking would provide would be negated by an increased risk of heart attack, and so there isn't any net gain to health overall.

  4. Not a Reasoning Objection16% picked this

    fails to address specifically the reduction in risk of stroke conferred by the level of consumption

    We're fine with hearing that 3 glasses a day would confer a substantial decrease in risk. We don't need to know whether it's specifically 37% or 42%, in order to assess the logic of this argument. Answers that are complaining that we didn't get a specific measurement, a specific statistic, or the specific names of people who may have been alluded to in the argument are almost always wrong. It's practically never the case that a missing number / name / definition is what creates a reasoning flaw.

  5. Irrelevant Distinction1% picked this

    overlooks the difference between strokes that result in death and less

    Yes, the author does fail to discuss distinctions between those two types of strokes, but that distinction doesn't make any difference to the argument. The argument is about whether 3 glasses of wine per day would benefit health. The reason some think it would benefit health is that such a routine would substantially decrease the risk of stroke. Which kinds of stroke? The fatal kind, the non-fatal kind, or both? Presumably both kinds, but it doesn't really matter. Decreasing your risk of any kind of stroke still qualifies as a health benefit, and that's all that matters to the logic of this argument.

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