Q17 - Warm air tends to be humid

[dan]

17. (A)
Question type: Application
The main flaw in the original argument is one of conditional logic. We can diagram the argument as follows:

warm air => humid
more humid => more rainfall
therefore, more rainfall => warm air

Just because warm air could eventually lead to more rainfall does not mean that, if there is more rainfall, it must have been because of warm air. This is faulty reverse logic.

Answer choice (A) exhibits the same faulty reverse logic:

fresh => nutritious
more nutritious => healthier
therefore, healthier => more fresh

(B) does not have faulty reverse logic.
(C) does not have faulty reverse logic.
(D) is flawed, but not in the same way as the original argument.
(E) does not have the same components as the original argument, nor does it have an easily apparent flaw.

[mrudula_2005]

I have always been told from seemingly everywhere to first always compare the conclusions in PR and eliminate wrong answer choices quickly just based on the structure of the conclusions alone so I quickly eliminated A since it stated "likely" - an uncertainty not found in the conclusion of the stimulus. Do you have advice on a more consistent approach to these parallel flaw/parallel reasoning questions? Because I spent a TON of time on this one since I crossed them all out and had to relook at everything again and again...thanks a lot!

[chike_eze]

Please help me classify the flaw in D.

Prompt - reversed logic flaw
A - same reversed logic flaw
B - Circular reasoning
C - Valid
D - ??
E - Seems Valid (please dissuade me of this notion)

My Thought Process for (D):
"more people overweight, and fewer people exercise" does not necessarily mean that exercise and fitness did not play a role in making people healthy, generally. It could be that the overweight and non-exercising folks represent but a small sample of the general public. Therefore, the conclusion would not necessarily follow?

Also, don't we have to assume that Overweight people do not live healthier and longer lives? Or is this implied?

Lastly, I noticed gaps between terms, e.g. "Overweight" and "Lean", "fewer people exercise" and "Physically fit". How significant is this?

Thoughts??

[noah]

My Thought Process for (D):
"more people overweight, and fewer people exercise" does not necessarily mean that exercise and fitness did not play a role in making people healthy, generally. It could be that the overweight and non-exercising folks represent but a small sample of the general public. Therefore, the conclusion would not necessarily follow?

I agree! That sample might have increased from 5% to 10% - that's a dramatic increase, but still a small part of the population.

Also, don't we have to assume that Overweight people do not live healthier and longer lives? Or is this implied?

I don't think we have to assume this - in fact, the argument is hoping that we don't. It wants us to think, for example, that 70% of the population are heavy and lazy (to paraphrase), but that we're living longer, including those folks. But, as you pointed out, that doesn't have to be the way the numbers play out.

Lastly, I noticed gaps between terms, e.g. "Overweight" and "Lean", "fewer people exercise" and "Physically fit". How significant is this?

I think the first one is OK (I think it's tough to say that someone that is lean is overweight - but maybe I'm missing something), but not the second one. You can exercise but not be physically fit. In fact, that completely describes me - I went hiking today, but I'm far from physically fit, as evidenced by the way I feel after that hike!

Nice work!

[farhadshekib]

I have always been told from seemingly everywhere to first always compare the conclusions in PR and eliminate wrong answer choices quickly just based on the structure of the conclusions alone so I quickly eliminated A since it stated "likely" - an uncertainty not found in the conclusion of the stimulus. Do you have advice on a more consistent approach to these parallel flaw/parallel reasoning questions? Because I spent a TON of time on this one since I crossed them all out and had to relook at everything again and again...thanks a lot!

When I first started my LSAT prep, I was in the exact same situation.

But I realized very quickly that Parallel Flaw is very different from Valid Parallel Reasoning questions.

For the latter, matching the conclusion works pretty well and, at times, it can actually eliminate all 4 incorrect answer choices.

The former, however, is much more abstract. It becomes really important to identify the flaw, first, before moving on to the answer choices.

For instance, if the flaw is an error of division/composition, the stimulus may read something like this:

"The United States is the wealthiest country in the world. Therefore, every American, who lives in the United States, is wealthy".

The correct answer to the parallel flaw may read something like this:

(D) "The Toronto Raptors are the worst team in the NBA. Therefore, Andrea Bargnani, who plays for the Raptors, is most likely one of the worst players in the NBA".

While the conclusions may use different degrees of likelihood (i.e. "is vs. most likely"), the flaw is the same.

Both arguments assume that what is true of the whole (i.e. US as wealthiest country in the world, and Raptors as worst team in the NBA) is also true of its parts (i.e. every American = wealthy and Bargnani, a Raptor, = crappy).

This is my understanding... If an instructor from MSLAT wants to confirm or refute my explanation, please do so.

[timmydoeslsat]

Please help me classify the flaw in D.

Prompt - reversed logic flaw
A - same reversed logic flaw
B - Circular reasoning
C - Valid
D - ??
E - Seems Valid (please dissuade me of this notion)

I would like to go over these that you have listed.

I would list the answer choices like this:

A) Flawed in same respect as stimulus

B) I would say this is invalid because it goes from "generally are" to "must"

C) Not valid because we do not know that they tend to use automobiles. Maybe they walk or use private jets.

D) Invalid because it could be discussing two separate groups. The fit and lean group could be lumped in with the group that is involved with longer and healthier lives.

E) Invalid because of a term switch going from "enjoy and appreciate" to satisfy.

My Aunt Sally may give me a small piece of cake that I enjoy and appreciate, but it does not satisfy me.

[noah]

I have always been told from seemingly everywhere to first always compare the conclusions in PR and eliminate wrong answer choices quickly just based on the structure of the conclusions alone so I quickly eliminated A since it stated "likely" - an uncertainty not found in the conclusion of the stimulus. Do you have advice on a more consistent approach to these parallel flaw/parallel reasoning questions? Because I spent a TON of time on this one since I crossed them all out and had to relook at everything again and again...thanks a lot!

When I first started my LSAT prep, I was in the exact same situation.

But I realized very quickly that Parallel Flaw is very different from Valid Parallel Reasoning questions.

For the latter, matching the conclusion works pretty well and, at times, it can actually eliminate all 4 incorrect answer choices.

The former, however, is much more abstract. It becomes really important to identify the flaw, first, before moving on to the answer choices.

For instance, if the flaw is an error of division/composition, the stimulus may read something like this:

"The United States is the wealthiest country in the world. Therefore, every American, who lives in the United States, is wealthy".

The correct answer to the parallel flaw may read something like this:

(D) "The Toronto Raptors are the worst team in the NBA. Therefore, Andrea Bargnani, who plays for the Raptors, is most likely one of the worst players in the NBA".

While the conclusions may use different degrees of likelihood (i.e. "is vs. most likely"), the flaw is the same.

Both arguments assume that what is true of the whole (i.e. US as wealthiest country in the world, and Raptors as worst team in the NBA) is also true of its parts (i.e. every American = wealthy and Bargnani, a Raptor, = crappy).

This is my understanding... If an instructor from MSLAT wants to confirm or refute my explanation, please do so.

Nice explanation, Chikeze.

The LSAT uses both modifier flaws and reasoning flaws to create wrong answers, so unfortunately/fortunately the answer is that you want to keep all those tools sharp and ready to use.

It's hard to imagine the LSAT fudging the modifier in a correct answer, but not in a wrong one, so if you end up seeing "likely" when you want something stronger, eliminate away. Since we want the best answer, there may be times that you end up eliminating all the answers - as you describe - and then have to use a less fine tool. In general, that doesn't occur, so keep on looking for those conclusion mismatches at first.

Overall, I think that this happened is a good sign that your process is going in the right direction.