#18 - If there are any inspired musical performances in the

[Administrator]

Complete Question Explanation

Must Be True—SN. The correct answer choice is (A)

This stimulus is comprised of three conditional statements:

Statement 1: If there are any inspired performances, it will be a good show:

• Inspired performances good show

Statement 2: There will not be a good show unless there are sophisticated listeners:

The term modified by “unless” (in this case, sophisticated listeners) becomes the necessary condition. The remaining term is negated and becomes the sufficient condition:

• Good show sophisticated listeners

Statement 3: To be a sophisticated listener, one must understand one’s musical roots:

• Sophisticated listener understand ones musical roots

By linking the above statements together we can form the following chain relationship:

• Inspired performances good show sophisticated listeners understand their roots

We can also draw the following chain contrapositive:

• Don’t understand roots not sophisticated listeners not good show no inspired performance

Correct answer choice (A) draws a valid inference from the chain contrapositive above:
If there are no sophisticated listeners, there won’t be a good show, and if it’s not a good show, there will be no inspired performances.

Answer choice (B) provides this Mistaken Negation of the above chain relationship:

• Not good show not sophisticated audience not understand their roots

Answer choice (C) provides this Mistaken Reversal of the chain relationship above:

• understand their roots inspired performance

Answer choice (D): This incorrect answer choice would be diagrammed as follows:

• not good show people don’t understand their roots.

This answer choice is a Mistaken Negation a valid inference from the chain relationship discussed above.

Answer choice (E): This answer choice reflects a Mistaken Reversal of an inference from the chain discussed above. This incorrect answer choice would be diagrammed as follows:


sophisticated listeners inspired performances

[lsat2014]

***The content of this question has been removed due to LSAC licensing restrictions***

The correct answer is A.

I understand why the correct answer is A, but I don't understand how B and D should be diagrammed and why they are incorrect.

The full diagram should look like this:

Inspired Musical Performances (IMP) Good Show (GS) Sophisticated Listeners (SL) Roots (R)

Option B and D should be diagrammed as
GS R
If there is not a good show, there should be no one who understands their roots. Why is this incorrect?

Thanks!

[Nikki Siclunov]

Hi lsat2014,

Thanks for your question! Your initial diagram of the stimulus is 100% correct. You are also correct in diagramming answer choices (B) and (D). Each of them is incorrect because it represents a Mistaken Negation. According to the original diagram, having a good show requires having listeners who understand their musical roots:

GS R

Meanwhile, answer choices (B) and (D) suggest that if you don't have a good show, you won't have such listeners:

NO GS NO R

This is not necessarily true. We can have listeners who understand their musical roots even if we don't have a good show, because having a good show is not a requirement for the presence of such listeners. By negating both sides of the conditional relationship without reversing the conditions, (B) and (D) are Mistaken Reversals of the original. Answer choice (A), by contrast, is given in the contrapositive form, which is a logically valid inference.

Hope this helps! Let me know.

[lsat2014]

Great, thank you for the explanation!

[Vexans]

Hello, I have a question regarding problem #6 in page 2-15. During the lesson 2 video the presenter did an excellent job explaining this problem and demonstrating how to create the logical sequence. My question however is one regarding test taking strategy when encountering a problem like this one. The presenter started by mapping out the logical string of the stimulus, and then went on to map out each of the answers. It turns out that in this case the first choice, answer "A" was correct. So my question is: Should we also map out each answer choice after finding that an earlier choice is correct? Or would you suggest that in the interest of conserving time we should mark answer "A" and continue to the next question?

Thanks!

[Luke Haqq]

Hi Vexans!

I'd definitely recommend the latter approach you mentioned--in the interest of time, mark (A) and go on to the next one.

This is especially true if you feel confident with an answer choice, and you have diagrammed conditional reasoning that proves why it's the correct answer choice. In the many instances where you don't encounter something that immediately appears correct in the first answer choice, getting into the habit of diagraming the answer choice out is a good habit/practice to get into, because doing so can help you determine much more quickly and accurately whether or not a given answer choice is correct. Thus it's also useful to diagram out an answer if you like it/dislike it but aren't sure--diagramming out the conditional reasoning is a quick way to figure out whether to keep or reject the answer choice.

[bigboyroeroe123]

Hi Powerscore,

I understand why A is correct and got it right. However, I have some problems regarding answer choice C.
I read the Formal Logic Chapter of the Bible, and it said from A-->B (All A are B) we can get inherent inference: B-s->A (Some B are A). I think C represents this logic relationship, so why is C wrong?
Is it because in order to get the inherent inference, it has to be "All, most, some" scenarios, "if...then..." scenario cannot get the inherent inference.

Thank you!

[Adam Tyson]

That's exactly right, bigboyroeroe123! A conditional statement based on uncertain terms like "if" cannot be used to infer a certain statement like "some" (meaning "at least one.") That's because "if" does not guarantee that the sufficient condition ever occurs!

"If I win the lottery, then I will retire and move to Spain" does NOT mean that some people who move to Spain won the lottery. Me winning the lottery never actually has to happen!

If I had said instead "All the people who have won the lottery so far have moved to Spain," that "all" means there have been at least some winners, and I could then say that some people who moved to Spain are lottery winners. In that conditional relationship, with a certain term indicating the sufficient condition, it would be okay to do that "some" reversal.

The stimulus is uncertain - "if" - so we cannot know that there have been or will be any such inspired performances, and cannot get to a "some" claim that goes in reverse.

Good work!

[bigboyroeroe123]

Thank you so much for your explanation! It's very clear!

[Laurenw3692!]

Hi!

I’m having trouble understanding why D is wrong. I understand why A is right, but couldn’t D be correct as well? I think i diagramed it correctly like this:
ip —> gs —> sl —> umr
or separately like this:
ip —> gs
gs —> sl
sl —> umr
(ip = inspired performance, gs = good show, sl = sophisticated listeners, and umr = understand musical roots)
prior to this the chapter stated “unless” makes something the necessary, and D states “the audience will be treated to a good show, unless there are people in the audience who do not understand their musical roots”
I understood this to make UMR the necessary (which it already is) and if you do not understand your musical roots, you’re not a sophisticated listener. then i thought it would follow that because you’re not a sophisticated listener, there won’t be a good show. Therefore, like D states: if there aren’t any people who understand their musical roots there won’t be a good show, because they’re not sophisticated listeners. I don’t know or see how this could be a mistake reversal or negation because if it was diagrammed like I had it:

ip —> gs —> sl —> umr

If you cross out UMR (because D says they don’t understand musical roots) don’t you have to cross out SL since UMR was the necessary, which means you would have to cross out GS since SL was the necessary for GS meaning if you don’t understand musical roots there won’t be a good show?
Am I missing something? i’m sorry if that is confusing. I also see trouble in the future with problems similar to this, is there any way to distinguish this in every question similar to this?

Thank you!!! )