## LR Help: Flaw in the Reasoning

Prepare for the LSAT or discuss it with others in this forum.
vamos

Posts: 47
Joined: Sat Jan 15, 2011 2:50 am

### LR Help: Flaw in the Reasoning

I'm not having trouble with all Flaw questions, only the ones with question stems which end with something along the lines of "fails to take into account the possibility that...". Any advice of tackling these questions? More specifically, PT50,S4,Q19. I've been stuck on this question for long time.

dr123

Posts: 3497
Joined: Tue Jan 04, 2011 2:38 am

### Re: LR Help: Flaw in the Reasoning

correlation =/= causation

benito

Posts: 321
Joined: Wed Oct 27, 2010 10:09 pm

### Re: LR Help: Flaw in the Reasoning

Actually the question clearly states that its NOT asserting causation between caffeinated beverages and heart disease, so the correlation=causation fallacy is not relevant to this question. The problem here is that the argument is assuming a correlation between two things ( caffeinated beverages and heart disease) based on the fact that they each have a correlation with a separate independent third thing (smoking). It would be like saying young people are more likely than others to go to law school, and young people are more likely than others to shoot up heroin. Therefore, there is a positive correlation between going to law school and shooting up heroin. Answer choice A exposes this flaw by pointing out the distinct possibility that caffeinated beverages have absolutely no connection to heart disease, because if smokers who drink them are less likely to develop heart disease than those who do not then heart disease might be positively correlated with smoking but certainly not with caffeinated beverages. Just as (I'd like to think at least) youth and heroin use may be positively correlated but law school and heroin use are not.

Since you don't have problems with other types of flaw questions I'd bet you were able to determine what the problem was with the argument. That's really the hard part, after that its just parsing the language in the answer choices and making sure you pick the one that accurately describes or exposes the flaw. When I did this PT the first time I didn't see it in answer choice A until I was able to discount the other choices and then take a closer look at A to grasp what it was really saying if I would have interpreted it right the first time I would have saved like two minutes. So don't let yourself get thrown off by the wording in the stimulus or question stem, just figure out what the flaw is and determine which answer choice, or "possibility" for this type of question, accurately exposes that flaw.

vamos

Posts: 47
Joined: Sat Jan 15, 2011 2:50 am

### Re: LR Help: Flaw in the Reasoning

benito wrote:Since you don't have problems with other types of flaw questions I'd bet you were able to determine what the problem was with the argument.

Even though I think I have a good understanding of all the major fallacies, in this particular question, what exactly is the fallacy being comitted? Here is my interpretation:

Smoking --- correlated --- Heart Disease
Smoking --- correlated --- Drinking Caffeineated Beverages
So, Heart Disease --- correlated --- Drinking Caffeineated Beverages

It looks to me like the author suggests that correlation implies correlation, but I wasn't aware that this was a fallacy.

Thanks.

benito

Posts: 321
Joined: Wed Oct 27, 2010 10:09 pm

### Re: LR Help: Flaw in the Reasoning

You have the structure of the bad argument down exactly right, but the flaw is just that when one thing is correlated with two different

things, in this case smoking is correlated with beverages and correlated with heart disease, it does not mean those two things are correlated

with each other. In fact it tells you absolutely nothing about the relationship between those two things at all. Just like incorrectly assuming

there is a relationship between going to law school and using heroin on the basis of their mutual correlation with youth. Clearly doesn't

follow logically right? I need a new example maybe.....

vamos

Posts: 47
Joined: Sat Jan 15, 2011 2:50 am

### Re: LR Help: Flaw in the Reasoning

Your example was a little exaggerated, but that's what made it a good example! I definately understand it now, these "flaw-possibility" questions are probably just throwing me off because they're not simply asking for which fallacy was committed. Thanks again.