Logical reasoning PrepTest 152 · Section 2 · Question 22

Incorrect. The argument doesn't discuss causality, nor does it establish any type of conditional relationship/necessity.

Incorrect. In order to contradict each other, the premises would have to establish both that monetary systems were first and barter systems were first, which it doesn't do. In fact, the problem is that the argument repeats itself, not that it contradicts itself.

Incorrect. The author doesn't make a recommendation or use language like "should" or "ought to," so this answer doesn't reflect the argument.

Incorrect. There's no causality in the stimulus, so this answer is incorrect.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Errors in Reasoning

Stimulus Summary:
History has examples where money disappears and economies reverted to a barter system, so the first economies must have been based on a barter system instead of money.

Answer Anticipation:
Why does the author conclude that the first economies were based on barter? Because when money disappeared in certain economies, they "revert[ed]" to a barter system. But in order to know that when money disappears an economy "reverts" to barter instead of moving to a barter system, it must be assumed that the economy started as a barter system. The premises provide equal support that this economy started as a money system and moved to barter when the money disappeared. So the argument is assuming that economies start as barter systems in order to prove that they started as barter systems. That's a circular argument! Rare, but it happens.

Answer Explanation:
The argument relies on a premise stating that a shift from money to bartering is a reversion instead of a development, to prove a conclusion that bartering predated money. There's no actual evidence that bartering came first, just an assumption/premise stating it, so this answer is correct.

Key Takeaway:
Circular reasoning is rare on the LSAT! Well, at least, it is as a correct answer, as it's one of the most frequent incorrect answers. If the conclusion isn't based on anything other than an assertion that it's true, then the argument is circular.