Logical ReasoningDifficulty: Hard

PT132 S4 Q13 Explanation

Many symptoms of mental illnesses

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

TopicsFlaw

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Stimulus

Many symptoms of mental illnesses are affected by organic factors such as a deficiency in a compound in the brain. What is surprising, however, is the tremendous variation among different countries in the incidence of these symptoms in people with mental illnesses. This variation establishes mental illnesses are not distributed evenly around the globe.

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
13.

The reasoning above is most vulnerable to criticism on the grounds

Answer choices

  1. Not a Flaw2% picked this

    does not say how many different mental illnesses are

    We never need to be that precise with definitions or measurements to judge someone's reasoning. Does it make any difference to this argument whether there are 5 or 15 or 30 illnesses?

  2. Opposite18% picked this

    neglects the possibility that nutritional factors that contribute to deficiencies in compounds in the brain vary

    This seems to reinforce the idea that organic factors (such as organic compound deficiencies) are spread unevenly around the globe.

  3. Correct70% picked this

    fails to consider the possibility that cultural factors significantly affect how mental illnesses manifest

    Why this is right

    This allows us to say that organic factors are evenly distributed, but there's a different causal factor that's unevenly distributed, hence the global variation in symptoms of mental illness.

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

  4. Too Strong: any5% picked this

    presumes, without providing justification, that any change in brain chemistry manifests itself as a change

    The author doesn't have to make the very extreme assumption that every single change in brain chemistry noticeably changes your mental condition.

  5. Too Strong: any5% picked this

    presumes, without providing justification, that mental phenomena are only manifestations of

    The author doesn't have to believe that mental phenomena are 100% caused by physical factors, just because she believes that many mental illness symptoms are affected by physical factors.

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