December 1991 LSAT Section 2 Question 13

If that insect is a bee, it can only sting once. It only did sting once. So it is a bee.Which one of the following ex...

zacharylouiskane@gmail.com on June 1, 2020

Knock Out A

When I was running through the practice upon closer look at the language setup of answer choice A.... when it says "because when it is spring, I cannot stop sneezing; and I just sneezed. My main takeaway as two why I personally crossed it out was because the author of this answer is saying he can't stop sneezing which is plural and he technically only "sneezed" is this a valid inference?

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zacharylouiskane@gmail.com on June 1, 2020

Ok I actually got it wrong. Why is that? What did I miss? I picked C.

Victoria on September 17, 2020

Hi @zacharylouiskane@gmail.com

Happy to help!

"If that insect is a bee, it can only sting once."

B --> SO
Not SO --> Not B

There are two flaws committed by the author of this stimulus.

The first flaw is that the author takes the presence of the necessary condition to conclude the sufficient condition.

P: B --> SO
P: SO

C: B

The second flaw is that the author takes the premise that the insect only stung once to conclude that it can only sting once. Maybe it can sting multiple times and it just hasn't gotten around to doing so yet. So, what is the flaw? The author draws a conclusion about the frequency of something based on it occurring only once.

Both of these flaws are mirrored in answer choice (A).

"When it is spring, I cannot stop sneezing."

S --> Not SS
SS --> Not S

The author takes the presence of the necessary condition to conclude the sufficient condition.

P: S --> Not SS
P: Sneeze (Not SS)

C: S

The author also draws a conclusion about the frequency of something (not being able to stop sneezing) based on it only occurring once (I just sneezed).

I'll admit that the use of the plural "can't stop sneezing" threw me off for a second here top. It maybe doesn't match up as perfectly as we'd like it to, but both the flaws made in the argument presented in the stimulus are mirrored in answer choice (A).

Answer choice (C) is incorrect because it doesn't commit either of the flaws committed in the stimulus.

OBP --> MEC
Not MEC --> Not OBP

This is a valid argument drawn using the contrapositive. Additionally, the author does not incorrectly draw a conclusion about the frequency of something based on it occurring only once. We know that OBP are always MEC and this painting is never MEC. Therefore, it is valid to conclude that it is not OBP.

Hope this helps clear things up a bit! Keep up the good work and please let us know if you have any further questions.

pmv231 on April 5, 2021

Technically this should be in the 'flawed parrallel reasoning' section instead then

Kyland on January 30, 2022

@philip i believe it is characterized by the question stem. The stem for this one is closer to parallel reasoning than a flawed parallel. A flawed parallel would be closer to "which one of the following is flawed in the same way as the argument above"

Abigail on February 1, 2022

Hello @pmv231 and @kyland,

Yes, you are right. In the majority of cases, Flaw Parallel Reasoning questions will be indicated by the question stem (mentioning that the argument in flawed). The question stem of this stimulus does not indicate the flaw, so that is why we classified it as Parallel Reasoning, even though it is a flawed argument.

I hope that clarifies things!