Logical ReasoningDifficulty: Hard

PT131 S3 Q23 Explanation

To predict that a device

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

TopicsMethod

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Stimulus

To predict that a device will be invented, one must develop a conception of the device that includes some details at least about how it will function and the consequences of its use. But clearly, then, the notion of predicting an invention is self-contradictory, one cannot predict what has already taken place.

What this question is testing

Method

Your task

Describe how the argument proceeds — the technique it uses to reach its conclusion.

Common trap

Answers that describe a method the argument doesn't actually use.

Winning move

Track the role each statement plays, then match that to the choice describing the same moves.

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

The question
23.

Which one of the following most accurately describes the technique of reasoning employed

Answer choices

  1. Out of Scope: "counterexample"2% picked this

    constructing a counterexample to a general hypothesis about

    Counterexamples are specific people/place/things/situations that go against a general rule. There is no general rule in this conversation, nor any specifically named people/place/thing/situation trying to go against that general rule.

  2. Correct60% picked this

    appealing to definitions to infer the impossibility of a kind

    Why this is right

    Is the conclusion an inference about "an impossible kind of occurrence"? Sure, the conclusion is saying that "predicting an invention will never occur (it's self-contradictory)". Is the evidence an appeal to definitions? Sure. The first sentence defines what it means to "predict a device will be invented". The last claim defines what "inventing means".

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

  3. Out of Scope: "hypothesis"24% picked this

    countering a hypothesis by indicating the falsehood of the implications of

    There's no hypothesis anywhere here. A hypothesis is a claim that attempts to explain a given phenomenon. There's no phenomenon that has occurred nor any explanation for why it occurred. Even if we considered the principle / notion / proposition in the first sentence as a hypothesis, that first idea gets countered by showing that it's self-contradictory, which is not the same as showing that it has false implications. "False implications" would be like, "If X were true, then Y would follow. But since Y is false, X must be wrong." Y, in that example, was the false implication. That's not the same as showing that a claim is internally contradictory. To be self-contradictory, you are saying "there's no way both of these things could be simultaneously true", but that's dealing with the claim itself, not an implication of the claim.

  4. Out of Scope: "scientific vs. conceptual"1% picked this

    pointing out how a problem is widely thought to be scientific yet

    Nothing in this paragraph talks about a problem that is widely thought to be scientific.

  5. Opposite13% picked this

    attempting to show that predicting any event implies that it has in fact

    The author is saying the opposite of this in his final claim: you cannot predict something that has already taken place. The author thinks that predicting an event implies that the event has NOT yet taken place.

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