Logical ReasoningDifficulty: Hard

PT129 S1 Q12 Explanation

One can never tell whether another person

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

TopicsPrinciple-Strengthen

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Stimulus

One can never tell whether another person is acting from an ulterior motive; therefore, it is impossible to tell whether someone's action is moral, and so one should action rather than its morality.

What this question is testing

Principle-Strengthen

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
12.

Which one of the following principles, if valid, most helps to justify

Answer choices

  1. Correct49% picked this

    The intention of an action is indispensable for an evaluation of

    Why this is right

    Intention = motive. Indispensable = required. If we express A in conditional logic, it’s saying “If you don’t have intention, you don’t have evaluation of morality”. That mimics the move from Premise to Subsidiary Conclusion: “if you don’t know true motive, it’s impossible to judge morality of an action.”

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

  2. Out of Scope: ‘praise’ / ‘blame’ / ‘value’.2% picked this

    The assigning of praise and blame is what is most important in the assessment of the

    The conversation is about whether we should evaluate morality or consequences. You can evaluate the morality of an action without going on to praise or blame someone. And an action can have value, apart from whether it has moral value. If we applied this answer's language structure correctly to the argument it would sound like “The knowability of motive is what is most important in assessing morality”.

  3. Trap1% picked this

    One can sometimes know one's own motives for a

    Too Weak / Out of Scope: "knowing your own motives". Beyond being far too weak to be correct on Principle-Justify, this answer pulls in an out of scope idea about “knowing your own motives”, rather than “knowing whether another person’s motive was ulterior”.

  4. Trap11% picked this

    There can be good actions that are not performed by a

    Too Weak / Out of Scope: "good person" Beyond being far too weak to be correct on Principle-Justify, this answer pulls in an out of scope idea about “a good person”, rather than “a good action”.

  5. Bad Premise Match36% picked this

    One cannot know whether someone acted morally in a particular situation unless one knows what consequences

    Bad Premise Match: Don't know consequences → don't know morality The author said “If you don’t know the motive of an action, don’t know morality”. This doesn’t match either of the moves the author made.

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