Logical ReasoningDifficulty: Easy

PT126 S4 Q26 Explanation

Astronomer: I have asserted that

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

TopicsFlaw

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Stimulus

Astronomer: I have asserted that our solar system does not contain enough meteoroids and other cosmic debris to have caused the extensive cratering on the far side of the moon. My opponents have repeatedly failed to demonstrate the falsity of this they should admit that my thesis is correct.

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
26.

The reasoning in the astronomer’s argument is flawed because

Answer choices

  1. Bad Evidence Match2% picked this

    criticizes the astronomer’s opponents rather than

    The author never criticizes the opponents. He says that "their arguments have failed, proving that I'm correct." This answer refers to the famous flaw Ad Hominem.

  2. Correct91% picked this

    infers the truth of the astronomer’s thesis from the mere claim that it has not

    Why this is right

    Is the author's conclusion saying her thesis is true? Yes, "they should admit my thesis is correct". Is the only piece of evidence saying, "my thesis hasn't been proven false"? Yes.

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

  3. Opposite5% picked this

    ignores the possibility that alternative explanations may exist for

    The author's thesis is actually agreeing that there must be some alternative explanation for the cratering, because there isn't enough debris in our solar system for THAT to be the explanation.

  4. Bad Evidence Match1% picked this

    presumes that the astronomer’s thesis should not be subject to rational

    There's nothing in the argument that suggests that our author thinks her thesis should never be rationally discussed or critiqued. She's just saying, the people who HAVE rationally discussed my thesis or ATTEMPTED to critique it haven't been able to disprove it. She's not saying they never should have tried in the first place.

  5. Not a Flaw0% picked this

    fails to precisely define the key

    A precise definition of meteoroid has nothing to do with the reasoning problem in this argument. If we switched the argument to this, it would be the same flaw: My thesis is that the cratering on the Moon could not have been caused by cheeseballs. My opponents have not been able to prove my thesis is wrong; thus they must admit it is correct. We don't need LSAT authors to name their sources or provide precise definitions or measurements.

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