Logical ReasoningDifficulty: Medium

PT2 S4 Q21 Explanation

Efficiency and redundancy are contradictory

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

TopicsMust be True

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Stimulus

Efficiency and redundancy are contradictory characteristics of linguistic systems; however, they can be used together to achieve usefulness and reliability in communication. If a spoken language is completely efficient, then every possible permutation of its basic language sounds can be an understandable word. However, if the human auditory system is an imperfect of a spoken language’s basic language sounds can be an understandable word.

What this question is testing

Must be True

Your task

Break the argument into its conclusion and evidence, then do exactly what the question stem asks with that structure.

Common trap

Answers that sound relevant to the topic but don't connect to the argument's actual reasoning.

Winning move

Predict what a right answer must do, then test each choice against the conclusion-evidence 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
21.

If all of the statements above are true, which one of the following must

Answer choices

  1. Trap3% picked this

    Efficiency causes a spoken language to be useful and redundancy causes it

  2. Trap3% picked this

    Neither efficiency nor redundancy can be completely achieved in

  3. Trap5% picked this

    If a spoken language were completely redundant, then it could not

  4. Trap12% picked this

    If the human auditory system were a perfect receptor of sounds, then every permutation of language sounds would

  5. Correct78% picked this

    If the human auditory system is an imperfect receptor of sounds, then a spoken language

    Why this is right

    Answer E is correct.

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

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