LSAT Discussion Forum

Complete Question Explanation

Main Point-SN. The correct answer choice is (C)

Since this is a fact-set stimulus with a strong conditional reasoning component, a typical Must Be True question will probably require us to use the conditional relationships between the facts and draw an additive inference from them. One simple way to do this would be to diagram these relationships in the following manner:

SNP = study of natural resources

L = leisure

PR = plentiful resources

• Premise #1: SNP → L (study of natural processes requires leisure)
  
  Premise #2: L → PR (leisure requires plentiful resources)
  
  Premise #3: SNPES (the early societies studied natural processes)

Given that the early societies studied natural processes and such study required leisure, it is reasonable to conclude that the early societies had plentiful resources:

SNPES → LES → PRES

Answer choice (C) is therefore correct.

Answer choice (A): This is a Mistaken Reversal of the additive inference from the first two premises (SNP → PR). Even though the study of natural processes requires plentiful resources, the availability of such resources is no guarantee that such studies would ever take place. Plentiful resources represent a necessary, but insufficient condition for the study of natural processes. This answer choice is incorrect.

Answer choice (B): The stimulus provides no evidence for the conclusion that having theoretical knowledge of the principles of plant generation and growth is a necessary condition for the cultivation of plants. This answer choice is incorrect.

Answer choice (C): This is the correct answer. See discussion above.

Answer choice (D): Since the author never compares agricultural and nonagricultural societies, the stimulus provides no evidence for this conclusion.

Answer choice (E): Given that the last sentence of the stimulus states that "these complex discoveries were the result of the active study of natural processes," it is unlikely that early societies could have discovered cultivation by accident. If this were true, the author's argument would be undermined. This answer choice is incorrect.

Hello,

Could please explain to me question 21, must be true review, lesson 3, virtual LSAt course.

there is a premise: people have leisure when resources are pleantiful. "when" introduces sufficient condition, but on your website (online student centre)it is said that leisure requires plentiful resources, which means that plentiful resources is necessary condition. Could you please explain why in this example "when" does not introduce sufficient condition.

thank you,

Mila

Hey Mila - that's an interesting one, and a great example of how careful you have to be when dealing with language and the ways in which the test makers can manipulate it to confuse you. The reason that we can say that leisure requires plentiful resources is really the result of the second part of that sentence: people do not have leisure "when resources are scarce" (i.e. No Plentiful Resources --> No Leisure, and the contrapositive Leisure --> Plentiful Resources). And that's what leads to the chain connection by which we find C to be the correct answer: Study Natural Processes --> Leisure --> Resources.

Thank you! I got it

Lesson Three HW, LR Must Be True Review, #21 states "...and people have leisure when resources are plentiful". In this case, 'when' precedes the necessary condition, but in Lesson 2 'when' is listed as a sufficient condition indicator. Is there an efficient way to catch this exception besides paying extra attention to statements that include the word 'when'?

Thanks a lot

Thanks for your question. That one can be tricky, because two conditional statements are introduced in one sentence. "When" introduces the sufficient condition: "People have leisure when resources are plentiful" could be rephrased as "When resources are plentiful, people have leisure":

resources plentiful --> leisure

Based on the remainder of the sentence, "..not when resources are scarce," we also know that when resources are scarce, people do not have leisure:

resources NOT plentiful --> NOT leisure

Let me know whether that clears this one up--thanks!

~Steve

Thanks Steve, that cleared it up. It seems like the take-away for this problem is to avoid using conditional indicators to identify sufficient or necessary condition solely based on their location in the sentence.

Thanks a lot!

Dear Powerscore,

I have a question on how to diagram the first statement,

Premise 2: Resources Plentiful--->People Have Leisure

However, in the explanations premise 2 said:

L--->RP

Please explain why?


Thanks

Ellen

Hi Ellen,

Thanks for your question. The author provides that people "have leisure when resources are plentiful, not whey they are scarce." The second part of that sentence provides that when resources are not plentiful (or scarce), people don't have leisure. So, if someone has leisure, resources must be plentiful.

I hope that's helpful--please let me know--thanks!

~Steve

But when introduces sufficient condition:


when resources plentiful--->have leisure

not have leisure --->not plentiful resources.


I am still confused, thanks.