Q22 - Although human economic exchange predates

[ohthatpatrick]

Question Type:
Flaw

Stimulus Breakdown:
Conclusion: First economies based on barter; money came later.
Evidence: There are numerous examples where in isolated places, the currency disappears and barter typically returns (whereas they go back to currency once currency is available again).

Answer Anticipation:
We might notice that our author is concluding something about all of humankind (by speaking about "the very first economies") and using as evidence a potentially atypical sample of isolated places.

It's also not really clear how talking about isolated places switching to a barter system when currency is unavailable is any evidence that "barter came first". Where did the author get the language of "revert to the ORIGINAL barter system"? Is that just assuming that barter came first?

Correct Answer:
E

Answer Choice Analysis:
(A) Conditional Logic Flaw (nec vs. suff). There was no conditional logic in the evidence, so move on.

(B) Self-Contradiction. This is normally wrong, but there WAS something weird about the fact that the author is selling us on the idea that "barter came first, then money". In the cited example, currency is there, then barter, then currency again. But that would be more like the premise undermines the conclusion. There are no contradictory premises.

(C) The author isn't arguing anything normative, so there are no presumptions about what SHOULD be done.

(D) The conclusion is not a causal idea, so we can't say the author infers a causal relation.

(E) YES! This describes Circular Reasoning, which is usually wrong, but we can justify it here by thinking: 1. This evidence seems kinda worthless. How does it prove anything about the very first economies? And 2. The author is only making it seem relevant by saying that they "REVERT to the ORIGINAL barter system". How do we know that they were ORIGINALLY a barter system? The author seems to just be presuming that, based on what he's hoping to prove in his conclusion.

Takeaway/Pattern: The mythical unicorn of Circular Reasoning! LSAT knows that we test prep companies are out here warning people, "NEVER pick Circular Reasoning or Self-Contradiction … they're never right!" (naturally, responsible teachers/companies aren't saying NEVER ... we're just saying the vast majority of the time). On one of the last couple tests, there was a correct Self-Contradiction answer, and now here we have a correct Circular Reasoning.

To justify actually picking a Circular Reasoning answer, you should be able to find something in the evidence that feels like a restatement of the conclusion, or you should be able to think "that evidence would only count as evidence if you already believed the conclusion".

#officialexplanation

[Ellesat]

Patrick, do you happen to recall which recent problem it was that involved premises contradicting one another?

[ohthatpatrick]

It's this one:
https://www.manhattanprep.com/lsat/forums/-t17464.html

[YudeS218]

Hey Patrick,

I don't understand this question.

In my opinion, Circular Reasoning means that the conclusion is merely the restatement of the evidence. For example, She is clever, because she is really clever.

It is not a formal logical fallacy but a pragmatic defect in the argument because the argument fails to be persuasive.

However, in this case, the evidence is just completely irrelevant. There is no way for us to infer the conclusion from the evidence provided.

Of course, as you said, "that evidence would only count as evidence if you already believed the conclusion". But what if there is an argument like: "Evidence: I am clever. She is my classmate. Conclusion: She is clever."

It might be ridiculous to contend that it is a Circular Reasoning because it is nothing more than completely non-sense.