Logical ReasoningDifficulty: Easy

PT106 S3 Q18 Explanation

The human brain and its associated

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

TopicsPrinciple-Strengthen

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Stimulus

The human brain and its associated mental capacities evolved to assist self-preservation. Thus, the capacity to make aesthetic judgments is an adaptation to past environments in which humans lived. So an individual’s aesthetic judgments must be evaluated they promote the survival of that individual.

What this question is testing

Principle-Strengthen

Conclusion

The author wants to say: aesthetic judgments — like which painting is beautiful — should be evaluated by whether they help you survive.

Evidence

Why? Because the brain evolved for self-preservation, and aesthetic judgments are part of brain function. So aesthetic judgment is, ultimately, an adaptation for survival.

Evaluate

The hidden move is the principle: That's not obviously true — you could evolve a capacity for survival and still evaluate it by other criteria (pleasure, aesthetics, social value). The argument needs the principle to make the leap from "evolved for survival" to "must be judged by survival."

Goal

Find the answer that supplies that principle.

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

The question
18.

Which one of the following is a principle that would, if valid, provide the strongest justification for

Answer choices

  1. Too Strong10% picked this

    All human adaptations to past environments were based on the human brain and its

    This says all human adaptations were based on the brain. The argument doesn't need that universal claim. It only needs aesthetic judgment, specifically, to be evaluable by its survival function. Whether other adaptations also went through the brain is irrelevant.

  2. Bad Match4% picked this

    Human capacities that do not contribute to the biological success of the human species

    This is a principle about which capacities can be evaluated at all. The argument doesn't question whether aesthetic judgments can be evaluated; it claims they should be evaluated by survival contribution. This principle answers a different question — and would in fact rule out evaluating non-survival capacities at all, which doesn't match the argument's positive claim.

  3. Correct83% picked this

    If something develops to serve a given function, the standard by which it must be judged is how

    Why this is right

    This is the principle the argument needs. If something develops to serve function Y, then it must be judged by how well it serves Y. Apply: aesthetic judgment developed to serve survival; therefore, it must be judged by how well it serves survival. That's exactly the conclusion. The principle bridges "evolved for X" to "judged by X."

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

  4. Bad Match1% picked this

    Judgments that depend on individual preference or taste cannot be evaluated as

    This says judgments based on taste can't be evaluated as true or false. The argument is concerned with how to evaluate aesthetic judgments by a different standard (survival contribution), not whether they have truth values. The principle doesn't bridge the argument's evidence to its conclusion.

  5. Bad Match2% picked this

    Anything that enhances the proliferation of a species is to be

    This says species-proliferation is what should be valued highly. The argument is about evaluating individual aesthetic judgments by individual survival. Species-level proliferation is a different (and broader) concept than individual survival, and "value highly" doesn't map onto "evaluate by." Doesn't bridge the argument.

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