Logical reasoning PrepTest 140 · Section 3 · Question 15

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Flawed Parallel Reasoning

Stimulus Summary:
Amoebas: Withdraw from physical damage
Humans: Withdraw from physical damage because it causes pain
Conclusion: All microscopic orgs can feel pain

Answer Anticipation:
This argument is heavily reliant on comparisons between humans and amoebas, and amoebas and all other microscopic organisms. And those comparisons are directly involved in the flaws here.

First, the argument assumes that, since humans and amoebas are similar in one way (they both withdraw from physical damage), they're similar in another (feeling pain—specifically, that pain motivates the similar behavior). Second, the argument assumes that if amoebas can feel pain, then so can all microscopic organisms. Those two jumps will be matched by the correct answer.

Answer Explanation:
This answer choice sets up a comparison between poets and people under hypnosis. It assumes that, since they're similar in one way (odd language use), they're similar in another (lowered inhibitions, which motivates the odd language use). It then jumps from this being true of poets to all artists, similar to the jump from amoebas to all microscopic organisms. Since this argument features the same two jumps as the stimulus, it's correct.

Key Takeaway:
Comparisons are a common reasoning type on the LSAT, so you should always note them when they show up. Seeing the two jumps here—comparing amoebas and humans, and treating amoebas as representative of all microorganisms—makes it a lot easier to find the answer that makes two similar jumps.

Incorrect. The conclusion here talks about "most corporations," as opposed to the conclusion of the stimulus about "all microscopic organisms." Additionally, both the premise and conclusion is about corporations, so there's no similar jump to the one from amoebas to all microorganisms.

Incorrect. This answer choice starts with a premise about athletes generally, and then it explores two specific examples of athletes, applying it to one in the conclusion. That doesn't feature the same jumps as in the stimulus since the premise is general (about all athletes), whereas the conclusion of the stimulus was general (about all microorganisms).

Incorrect. The conclusion here states something is "probably" true of a specific subset of predatory birds/animals, so it's different enough from the stimulus in relevant ways to mean it can't commit the same flaws. Remember, the stimulus was flawed because it jumped from one microorganism to all microorganisms—the correct answer needs the same jump, which it can't do in a conclusion about one type of predatory bird.

Incorrect. This answer compares New Mexico and British Columbia, but it never jumps to a broader generalization in the conclusion, so it doesn't have the same flaw.