PrepTest 106

[lcid:3521] Prep Test 106 LSAT — Logical Reasoning — S2 Logical reasoning

Question prompt

Wirth: All efforts to Remaining source text redacted.
Why the credited answer is right

Credited answer: A

The notes below walk through why it fits the stem and how to eliminate the rest.

Argument or Facts

Argument/Argument

Valid or Flawed

Flawed/Valid

Question Type

Point at Issue Questions

Stimulus Summary

W: All efforts have failed to ID a manic depression gene, and experts agree it doesn’t exist, so no one is genetically predisposed to manic depression. C: Your premises? Right. Your conclusion? Wrong. Many experts agree it’s a mix of genes that predispose people to manic depression.

Answer Anticipation

Whenever a Methods of Reasoning question features a second speaker, we should start with a couple considerations: Does the second speaker agree or disagree with the first speaker’s conclusion? If she disagrees, does she think it’s wrong or unsupported? Does the second speaker agree or disagree with the first speaker’s premises? Logic/assumptions? Does she bring up a new consideration? Here, Chang tells us how he feels about both of these things! He agrees with Wirth’s premises while disagreeing with her conclusion. That must mean that he either points out a flaw in her argument, or he presents new information/considerations. And in talking about multiple genes leading to manic depression, he doesn’t question her logic but rather brings in new information. Let’s find an answer reflecting that.

Answer choices

  1. A
    It presupposes only one Remaining source text redacted.
    Why choice A matches the stem
    Ah, these answers are phrased a little differently than we expected! It’s about how Chang expresses his view, not how we would characterize it. That’s fine - we can still use our anticipation here. Does this answer hint at new information? It does - it speaks to more than one possibility existing. Wirth assumes that there’s only one possible way genes could lead to manic depression - a single manic depression gene. Chang points out that this isn’t the only possibility - it could be several genes that predispose someone to manic depression. This answer therefore accurately characterizes Chang’s criticism of Wirth’s argument, so it’s the correct answer.
  2. B
    It depends on separate Remaining source text redacted.
    Why choice B is not credited
    Does Chang say that Wirth’s argument depends on contradictory information? No! In fact, he agrees with her premises, and he wouldn’t if they contradicted each other. Note that this is about contradictory evidence/premises, not a premise that contradicts the conclusion.
  3. C
    It relies on the Remaining source text redacted.
    Why choice C is not credited
    Chang relies on many of the same experts as Wirth, so he wouldn’t point out that her experts are the wrong experts to ask.
  4. D
    It disallows in principle Remaining source text redacted.
    Why choice D is not credited
    This is a variation on the Circular Reasoning flaw - the argument assumes that any evidence against the conclusion must be false. But Chang brings in new information - she doesn’t point out a flaw in Wirth’s.
  5. E
    It treats something that Remaining source text redacted.
    Why choice E is not credited
    Chang doesn’t point out a shift in strength between Wirth’s premises and conclusion. And Wirth doesn’t even treat a genetic basis for manic depression as impossible - just impossible if the experts are right!

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