Logical ReasoningDifficulty: Easy

PT119 S3 Q4 Explanation

Detective: Bill has been accused

A free, expert breakdown of this official LSAT Logical Reasoning question.

TopicsFlaw

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Full official LSAT questions are available through LawHub. This page provides LSAT Lab's explanation, strategy, and review tools without republishing the full official question.

Stimulus

Detective: Bill has been accused of committing the burglary at the warehouse last night. But no one saw Bill in the vicinity of the warehouse. So did not commit the burglary.

What this question is testing

Flaw

Your task

Describe the reasoning error the argument actually commits.

Common trap

Answers that name a real logical flaw the argument doesn't actually make.

Winning move

Articulate the gap in the reasoning yourself, then match it to the choice that describes that gap.

Reading along? Open the full official question in LawHub — we show a fragment here and keep the reasoning in our own words.

The question
4.

The reasoning in the detective’s argument is most vulnerable to criticism on the grounds

Answer choices

  1. No Evidence1% picked this

    treats evidence that is irrelevant to the burglar’s identity as if

    There is no evidence presented. The author's evidence is that "there is no evidence". To the extent that the author is talking about whether anyone saw Bill at the scene of the crime, his physical appearance (that nobody saw) is definitely relevant to his identity.

  2. Not Ad Hominem0% picked this

    merely attacks the character of Bill’s

    The evidence doesn't say anything bad about the accusers. This answer choice refers to the famous flaw Ad Hominem.

  3. Opposite3% picked this

    fails to provide independent evidence for the theory that Bill committed

    This author is concluding that Bill is innocent. This answer would be correct if it said that the author "fails to provide (his own) independent evidence that Bill did not commit the burglary".

  4. Correct95% picked this

    treats a lack of evidence against Bill as if it

    Why this is right

    The premise is about a lack of evidence, "nobody saw him in the vicinity". And the conclusion is an exoneration, "Bill did not commit the burglary". This describes the move from Unproven to Proven False.

    Skill tested: Flaw · how this choice captures the argument's function is the move to repeat next time.

  5. Not a Flaw0% picked this

    fails to establish the true identity of

    You don't have to solve the crime in order to prove that someone's innocent. The author is only trying to prove that Bill didn't commit the crime. If he has a rock solid alibi, we can know that it wasn't Bill, even if we never learn who did commit the burglary.

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