Logical reasoning PrepTest 140 · Section 1 · Question 14

Incorrect. This answer does introduce a hypothesis that's rebutted, but the rebuttal points out that evidence suggests an implication of it is highly unlikely, not absurd.

Incorrect. The premise here is that some theories are mutually exclusive with others ("cannot all be true at the same time"), not that there's an absurd conclusion reached that's based on an infinite regress. Since the premise doesn't match, this answer is wrong. Note that it does use similar language ("infinite number") in order to try to get you to ignore the logic and focus on the language.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Parallel Reasoning

Stimulus Summary:
Some philosophers propose an explanation for vision, but it must be wrong, because it would require an absurd infinite regress.

Answer Anticipation:
The argument points out that a hypothesis must be wrong because it leads to an absurd situation—an infinite regress. Lucky for us, that's a common method of reasoning—a reductio ad absurdum, or an argument that attacks another by pointing out that the logic behind it leads to a ridiculous or undesirable conclusion. The correct answer, therefore, should similarly rebut an argument by pointing out that it's logic results in absurdity.

Answer Explanation:
This argument presents a theory that is rebutted because it leads to an impossible situation (another infinite regress). That's the same method of reasoning as the stimulus, so this is the correct answer.

Key Takeaway:
When Parallel Reasoning questions feature a common method of reasoning, use that to your advantage to find the correct answer!

Incorrect. This answer tries to get you to select it by using the language "absurd," but it's a definition and not an argument that is being called absurd. There's also no infinite regress (no support under support under support etc . . . ), so this answer isn't parallel.

Incorrect. This answer doesn't conclude that another theory is absurd or wrong, instead coming to a definitive conclusion about the Library of Alexandria. Since the conclusions don't match, we can rule this answer out.