LSAT 152 | Section 2 | Logical Reasoning: Q22

LR Question 22 Explanation

QUESTION TEXT: Although human economic exchange predates historical…

QUESTION TYPE: Flawed Reasoning

CONCLUSION: Barter was the original system and came before currency.

REASONING: When currency vanished, people returned to the original system, barter.

ANALYSIS: This is a circular argument. They’re very rare on the LSAT, because it’s hard to write a circular argument that doesn’t sound obvious moronic (i.e. “This is the best pen because it is the best!”)

So the question writer did a good job here. I knew the argument was fishy, but couldn’t prephrase it as circular. However, I figured it out once I got to E. I think I failed to prephrase because the flaw is so rare.

I mention this to say not to worry too much about getting a prephrase: I spend maybe 5-10 seconds determining that yes, I understood the argument, but couldn’t spot a prephrase. In such a case, it’s legit to expect an answer may give you an idea. The most important thing is to have a clear understanding of what the question said, even if you don’t see the flaw.

As for the argument itself: the author says economies “revert to the original” barter system, as evidence for the conclusion that barter was original. But that’s exactly what we’re trying to prove! They’ve provided no evidence that barter was original.

It’s possible, for example, that things start as a gift economy, then move to currency. If currency disappears, then maybe people use barter (for the first time) and then move to currency once it’s available. In this case, there’s no “reverting” to original barter. Instead, barter was a new system that people switched to when currency went away.

___________

1. This describes a sufficient/necessary flaw. That’s different.
    
   Example of flaw: To use currency, and economy must leave behind barter. So, if an economy leaves behind barter, they must have started using currency.
2. Contradiction is almost never going to be the correct answer, because an internal contradiction is devastating to an argument and almost too stupid for an LSAT author to do. A contradiction is a “Red is best, green is best, therefore green is best” level of stupidity in an argument.
    
   Example of flaw: Currency is better than barter. But, the barter system has many advantages. These advantages mean that barter is better than currency. Therefore, the best system is clear.
3. This answer describes an argument from tradition, which is different.
    
   Example of flaw: Who needs these newfangled coins. We used to just trade a sheep for wheat in my day, and I say we keep doing that, without money.
4. This is a causation/correlation flaw. That’s different. There is no causal relationship stated in the stimulus. The argument is only about what came first, not what caused what. (The stimulus didn’t say barter was the cause of the shift to currency, there could be some other factor that comes along with barter that causes the shift).
    
   Example of flaw: Barter systems occurred before currency. So barter systems cause currency to develop.
5. CORRECT. See the analysis above. The author is arguing that barter is the original system. But then their evidence is that when currency disappears, people revert to “the original” barter system. They didn’t provide any direct evidence that it was original! They just said it twice. To be original, you’d have to show the barter was before the currency, not after. The only evidence they provide shows barter occurring after currency, and so the only reason we think barter is original is because they called it “original” in both the reasoning and the conclusion.

Recap: The question begins with “Although human economic exchange predates historical”. It is a Flawed Reasoning question. Learn more about LSAT Flaw questions in our guide to LSAT Logical Reasoning question types.