Q18 - The probability of avoiding heart

[yoohoo081]

Could someone explain this? So confused why a is answer and not c.
thank u!

[LSAT-Chang]

I am having a hard time as to understanding the "flaw" in this problem overall. I thought the flaw was that the premises talk about avoiding heart disease and the conclusion all of a sudden deals with maintaining good health. WHo is to say that avoiding heart disease equals maintaining good health?? It's as if the conclusion is suggesting that avoiding heart disease is all that matters to maintaining good health! So I thought "what if avoiding dairy foods is actually harmful to OVERALL good health?" So I chose (D) because that was the closest I could find to represent the flaw I spotted. I was looking for an answer choice that said something like: "the argument assumes that an increased probability of avoiding heart disease leads to an increase of maintaining one's good health"... Ugh.. this whole section seemed really hard.

[ilona11223344]

Hi,

here is my view as to why the answer is A:

Evidence:

Avoid dairy food --> less likely to eat fat --> better chance of avoiding heart disease

Conclusion:
Avoid dairy food --> will lead to better chance of maintaining good health

My first reaction after reading this was that heart disease is not the same thing as maintaining good health (and this is the argument's assumption) and I think (A) is the one that comes closes to show this -(A) basically says that even though eating dairy food may have potentially negative consequences, the elimination of dairy food may also have negative consequences - we don't know that avoiding dairy food will lead to maintaining good health because we don't know anything negative that may happen if you avoid dairy food - does this make sense?

Here is my take on the other answers:
(B) it's not doing this because it's using subtle language with words like 'likely to' 'probability' - so the author does not assume that this is the only way of decreasing the risk of heart disease
(C) No - this is not the assumption of this argument; the argument is arguing that elimination of factors that cause a decrease of probability of a bad consequence will lead to an additional benefit - maintaining good health
(D) this was extremely tempting to me - but the problem with it is that the argument does uses relevant evidence - it just makes a leap from saying that avoiding dairy food will lead to decreased probably of heart disease to saying that avoiding dairy food will be beneficial to your health - the assumption is the leap; the evidence is nevertheless relevant
(E) The argument is not saying that this will 'necessarily' happen - the author does state that it is probably and not necessary - so this is out

Hope this helps!

[cdjmarmon]

I thought we wouldnt be able to conclude anything off of "Not avoiding dairy" or "eating dairy food"? Wouldnt that be a mistaken negation or mistaken reversal of the logic chain?

Premise:Avoid dairy food --> less likely to eat fat --> better chance of avoiding heart disease

We cant say ~Avoid dairy food (Eat dairy) --> less likely to eat fat --> better chance of avoiding heart disease

[crazinessinabox]

I had similar thoughts as those posted above, particularly that there was something of note in allegedly switching from "avoiding heart disease" in the first sentence to "maintaining good health" in the last sentence.

I think it's a fair assumption that avoiding heart disease increases the probability[i] of maintaining good health (I think noting the language - "probability" - in the last sentence is key). In eliminating (D), my reasoning was that good health could reasonably be an umbrella under which avoiding heart disease could fall. Thus, increasing the probability of avoiding heart disease could indeed increase the probability of maintaining good health. I think the "probability" language allows for this sort of umbrella interpretation and doesn't mean we have to equate good health with heart disease alone.

As for conditional logic, I didn't actually diagram this during my timed PT. I chose the correct a.c., but marked it for further review.

[i]Avoids fat --> increase probability of avoiding heart disease
Avoid dairy --> increase probability of avoiding fat
Thus, Avoid dairy --> increase probability of maintaining good health

Linking it together: Avoid dairy --> increase probability of avoiding fat --> increase probability of avoiding heart disease --> increase probability of maintaining good health

(note that I didn't use "avoid fat" which is why I hesitated with diagramming this in the first place)

But, even if avoiding dairy does increase the probability of avoiding heart disease, what if avoiding it can lead to other problems that decrease the probability of maintaining good health (like, osteoporosis).

To be honest, after all this LSAT studying, sometimes I have to remind myself to go with my gut, with what makes sense to me in the real world, especially when I'm struggling with what appears to be a mechanical point.

[timmydoeslsat]

Good post above. I will say that this argument absolutely has great support for the idea that avoiding dairy foods will increase the probability of avoiding heart disease.

The issue is, as you say, in the conclusion about probability of maintaining good health. Answer choice D is too extreme by talking about relevancy, as our evidence is absolutely relevant to health.

While avoiding dairy will help in terms of health regarding the increased likelihood of avoidance in heart disease, this argument has not shown us what else might arise with avoiding dairy. It could very well be true that there are severe downsides to this.

[alandman]

As far as answer choice C is concerned, I think it is wrong because the argument doesn't say that dairy OUGHT or MUST be eliminated. The argument just tells us that IF it is eliminated, then the probability of good health is increased.

[ohthatpatrick]

Nice discussion everyone. I was about to make the same clarification about (C) as the last poster did, so I'm just useless here.

Let me know if anyone has lingering questions.

=== in regards to the diagramming question, I'm not sure where you got ~Avoid dairy (i.e. "eats dairy). In both the premise and conclusion, the author says "if you Avoid Dairy". ====

[Dkrajewski30]

I chose D. for this one. Upon review, I clearly see why A. is right, as A. concretely addresses the term mismatch between 'avoiding heart disease' and 'maintaining good health'. When going through this question (during a strictly timed PT), I quickly eliminated A., not seeing its relevance, and then I eliminated every other answer aside from D., as I couldn't think of any firm reason to eliminate it. D. seemed to point out a flaw in the argument - perhaps the most general flaw of all - that the drawing of the conclusion wasn't warranted given the premises of the argument - at least that's how I interpreted D. So in that case, I was thinking, this must be the correct answer choice.

But this had to be a faulty interpretation. It seems I'm conflating the failure to show that the evidence has relevance to the conclusion with the failure to show that one is warranted to make the conclusion given the evidence provided. But as I'm further reviewing this question, this just isn't the case. Evidence may be relevant to an argument, but that doesn't mean it has enough logical force to trigger a certain conclusion. I'll try to provide another example for myself in order to get this more firmly, and maybe it'll help others who made a similarly faulty interpretation.

I can use evidence about evolution and the fossil record in order to conclude that the Earth is older than what creationism says it is. There isn't much reason to doubt this. I can also use such evidence to conclude that a chimp will soon give birth to a human being, or vice-versa, given our evolutionary past. Now, this evidence is no doubt relevant to my conclusion. Referencing our evolutionary connection to primates makes the case stronger, even if only marginally, that a cross-species birth will take place. But it's still an absurd conclusion to make. So yeah, I'm right to use the evidence I used, but my conclusion isn't warranted.

[rickytucker]

I keep getting these type of flaw questions wrong and it's annoying, so I'm going to do a write-up of this one to try to solidify the reasoning in my head. Apologies in advance for being that guy that says, "this is the classic [insert common LSAT reasoning structure]...". I just want to say to that guy: thank you for reminding me of my incompetence and for reinforcing that I am average at best, actually I have the LSAT to thank more so.

With that, this is the CLASSIC flaw with a conditional statement. Whenever you're asked to identify the flaw in a conditional statement the correct answer will probably be in form of "fails to consider some are not". For example if all As are Bs (A --> B), the argument fails to consider some As are not Bs (A <-s-> ~B) or some Bs are not As (~A <-s-> B).

Plugging in the facts of question 18 we have a conclusion that asserts that all instances in which one avoids dairy foods, there will be an increased probability of maintaining good health (Avoid Dairy --> Increased Probability MGH). So with the "fails to consider some are not" scenario stated above we have: fails to consider that in some instances in which one avoids dairy, there will NOT be an increased probability of MGH (AD <-s-> ~Increased Probability MGH).

This is what answer choice (A) states: "... ignores the possibility that even though a practice (consuming dairy) may have potentially negative consequences, its elimination (avoiding dairy) may also have negative consequences (~Increased Probability MGH), i.e. AD <-s-> ~Increased Probability MGH).

(B) seems like it follows the above formula in its some Bs are not As construction, in context: ~AD <-s-> Increased Probability MGH. But I think it's wrong because of "decreasing the risk of a certain type of occurrence", which seems to be in reference to the premise: "increased probability of avoiding heart disease", while the conclusion is about "increased probability of maintaining good health". I would equate "decreasing risk" with "avoiding heart disease" more than I would equate it with "maintaining good health", so this is not a flaw committed in moving from the premises to conclusion.

(C) Stimulus doesn't presume "ought to", only says "if you avoid dairy...".

(D) Evidence: more likely avoid heart disease; conclusion: thus more likely to maintain good health. Less heart disease seems relevant to a better health.

(E) Would be correct if the stimulus said that something that is probable will necessarily occur. The stimulus is riddled with language of likeliness and probability but never asserts necessity, thus it doesn't commit the flaw of "some things that are probable are not necessary".

[ericha3535]

Can someone go in depth about answer choice d?

[christine.defenbaugh]

Some really great thought breakdowns going on here! I'd like to try to tie everything together into one chunk, and knock out some lingering questions. Here's the simplified breakdown:

PREMISE
avoiding dairy --> eating fat less likely
avoiding fat --> avoiding heart disease more likely
CONCLUSION
avoiding dairy --> good health more likely

Notice a few things:

1) The statements involve comparisons, not absolute conditionals
These are not strict/absolute conditionals. It's not "if no dairy --> no fat". It's a comparative statement. If you avoid dairy, the that makes it less likely you'll eat fat. Less likely than what? Less likely than if you were eating dairy.

As a result, the idea that "eating dairy makes you more likely to eat fat" is completely supported. This is not an illegal negation, since the original statement gave us a comparison of "less likely".

If I said "Eating chocolate makes me happier" - what does that mean? Eating chocolate makes me happier than not eating chocolate does. So, eating chocolate makes me happier, and not eating chocolate makes me sadder. The original statement tells me both things.

2) The statements are applied in general, not as absolute rules
These are not strict/absolute conditionals. It's not "if no dairy --> no fat". The idea that 'avoiding dairy makes eating fat less likely' does not mean that every time you avoid dairy, you will ALWAYS be unlikely to eat fat. It means simply that, generally speaking, avoiding dairy makes eating fat less likely.

As a result, the conclusion cannot be taken down by a mere single instance of avoiding dairy not resulting in a higher probability of good health.

3) We can support the idea that eating dairy makes heart disease less likely
We can combine the two premises. If avoiding dairy makes eating fat less likely, and avoiding fat makes getting heart disease less likely, then it seems reasonable to say that, in general: avoiding dairy makes heart disease less likely.

The problem, as a number of posters have pointed out, is that the conclusion makes the further leap to good health being more likely. Where did that come from!? Avoiding dairy might make heart disease less likely, but still make good health less likely in general - maybe a lack of milk gives you vicious toe fungus.

Darned if you do, darned if you don't. If you eat more dairy, you'll increase your chances of heart disease. But if you eat less dairy, you'll increase your risk of vicious toe fungus. Suddenly, the idea that avoiding dairy makes good health more likely is not so clear.

(A) Captures this possibility perfectly. The practice (eating dairy) may have potentially negative consequences (increased risk of heart disease), but the elimination (avoiding dairy) may also have negative consequences (increased risk of vicious toe fungus). And if that's true, the conclusion is no longer supportable.

Not the Problem
(B) This would be the flaw if the conclusion were "if you decrease your risk of heart disease, you must be avoiding dairy". The argument never claimed or assumed there was only a single way of decreasing risk.

(C) There's no recommendation language (ought, should, etc) anywhere in the stimulus.

(D) Relevance

The evidence is surely relevant. It's not sufficient to guarantee the conclusion, but that doesn't mean it's wholly irrelevant.

If I said "I have plenty of pasta, therefore I have all the stuff I need to make lasagna", that evidence about the pasta isn't irrelevant! It's good to know! But it's not sufficient to support the conclusion that I have *everything* I need for making lasagna.

Now, if I said "I bought a pair of earrings today, therefore I have all the stuff i need to make lasagna", then you could accuse me of bringing irrelevant evidence to the table.

Information about increasing or decreasing the likelihood of heart disease is entirely relevant to the question of the likelihood of good health. It's just not the whole picture.

(E) All the statements, including the conclusion, are in probabilistic language - nothing shoots for a definite!




I hope this helps clear up a few things on this very sticky flaw question!

[kyuya]

I wanted to make a comment about (A) that may make something clearer. Christine already explained everything else perfectly.

I think that it is indeed important that the question ultimately ends with saying chances of "good health" (I am not claiming anyone said this was not important - just want to make the connection more explicit from this to the flaw) -- a term switch I was immediately aware of for this question, however, got it wrong.

I ended up picking (D), because I interpreted "relevant" as "sufficient to prove" , in my attempt to make the conclusion that these premises do not necessarily lead to GOOD HEALTH. Good health may be very complex, and thus need more information.

So - -we do not actually know what constitutes good health. This could actually require dairy. We don't really know. Taking this into account, (A) may be a bit more clear in how it relates to the flaw in the stimulus.

"even though a practice may have potentially negative consequences" -- in reference to dairy ..

"it elimination (dairy's elimination) may also have negative consequences (on good health)"

I think when we see a term switch in the end like that, we must ask ourselves in the evidence actually supports this new conclusion, since a new term in the conclusion may be quite different.

[tommywallach]

Thanks so much for all the great posts, Kyuya!

-t

[alexcyt1995]

I'm not sure why E is wrong.

It's true that the stimulus does not address much certainty, but the conclusion "the probability is increased by avoiding dairy foods" sounds pretty certain to me. Here is my analysis

Premise 1: If one avoids fat, then probability of avoiding heart attack increases.
This is a conditional statement, so it guarantees that the probability will increase if one avoids fat. Although the premise contains probability, still it is certain that the probability will increase, not that it's likely to increase

Premise 2: If one avoids dairy foods, one is less likely to eat fat
This is also a conditional statement, but this one contains less likely. It guarantees people will be less likely to eat fat, or more likely to avoid fat.

Conclusion: If one avoids diary foods, the probability of avoiding heart attack will increase.

GAP: That's not true. If one avoids diary foods, the probability of avoiding heart attack could increase, but not necessarily.

I think the conclusion implies that the probability will necessarily increase. . So it seems to me that E is correct.

Could anyone help me with this? Thanks!

[LukeM22]

I just wanted to bump this thread as I had the exact same analysis of answer E as the above poster-- that "the probability of maintaining good health IS increased by avoiding dairy foods" sounds like a definite, conclusive statement on what will necessarily happen. What else is wrong with that answer?

[ohthatpatrick]

Yes, the author's conclusion is certain that probability will increase.

But the flaw is just that the author is saying "Probability of maintaining good health" vs. "Probability of avoiding heart disease".

There's nothing wrong here with the author saying that a probability is certain to change. Had the author concluded "Thus, the probability of avoiding heart disease is increased by avoiding dairy foods", then he's got a reasonable argument.

The author's two premises link together definitive rules:
If avoid dairy, then certain to lower probability of eating fat.
if avoid fat, then certain to lower probability of heart disease.

When you read a flaw answer choice that says
"The argument fails to consider that what is _____ will not necessarily be ____", then it will only be a correct answer if the first blank is describing what we know from the premise, and the second blank is describing what the author is assuming or claiming in the conclusion.

Was there a premise about something that was PROBABLE?

There was not. Probable = a probability greater than 50%.

The evidence is saying that you are CERTAIN to increase or decrease your likelihood of certain things, but at no point are we saying that something is "likely" / "probable".

Because the conclusion is saying you will NECESSARILY increase your probability of maintaining good health, (E) would demand that we had evidence that established that we were PROBABLY going to increase our probability of maintaining good health.

The evidence doesn't even talk about 'maintaining good health', so that there's no way to match (E) up.

[ZarkaS555]

I was tempted by D because all of the other answer choices seem to talk about the "elimination" of dairy. To me, that seemed like an unnecessary leap from the stimulus, in that the stimulus asks you to "avoid" dairy, not eliminate it. You can avoid something without eliminating it and I chose D because that seemed like the only choice that skirted that issue. Not sure how I could have "avoided" this misunderstanding?

[ohthatpatrick]

I think if the 2nd premise mentions "avoiding eating dairy foods" and then the Conclusion is about "avoiding dairy foods", then it's weird for us to criticize the author for failing to show that the evidence is relevant to the conclusion.

RELEVANCE is a pretty low bar to clear.

Also, the 1st premise was about "avoiding [a type of] disease" and the conclusion is about "maintaining good health".

So it seems like both of the concepts in the conclusion are directly relevant to the concepts being mentioned in the evidence.

"Avoiding [a type of] disease" is relevant to "maintaining good health".
"avoiding eating dairy foods" is relevant to "Avoiding dairy foods".

Also, I think we can live with "avoiding something" as a synonym for "don't expose yourself to it at all".

If I say, "Avoid Lucy as much as possible", I'm saying "sure maybe you'll see her a little, but definitely don't see her a lot".

If I say, "Avoid Lucy", I'm saying "don't see Lucy. Eliminate her as a presence in your life."

[mswang7]

Premise: Prob of avoid heart disease increases by avoiding fat
Prob of eating fat decreases by avoiding dairy
Concl: Prob of main good health is increased by avoiding dairy
Prephrase: Term shift that assumes avoiding heart disease implies good health

A. Is saying there may be negative consequences of avoiding dairy that reduce overall health. I'm weary since this doesn't solve our term shift issue keep for now.
B. Argument did not say dairy is the only route to good health
C. I would argue that the second premise justifies the elimination of dairy
D. Despite initially choosing this, after reading some other posts, I now understand avoiding dairy/ fat/ heart disease is relevant to good health
E. Argument is not trying to argue what will or won't occur - out of scope

By process of elimination A in the answer