Logical Reasoning

PT12 · S4 · Q8 A history book written hundreds

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A history book written hundreds of years ago contains several inconsistencies.

Conclusion (must have)

The author must have gotten information from more than one source.

Evidence (because)

The book contains several inconsistencies.

Evaluate

In terms of predicting a missing link, this argument is so short and sweet that we can just say, "If Premise, then Conclusion":

If a book has inconsistencies. then the author used more than one source.

The contrapositive of that assumption would be: If an author uses only one source, there won't be inconsistencies.

But we might also react to this argument as an Explain Curious Fact style argument. People are trying to solve the mystery of, "Why does this book have inconsistencies?"

The hypothesis we're getting is, . We could weaken the argument with alternate explanations for why there are inconsistencies. Maybe there were multiple authors with different ideas.

Goal

Let's look for an answer linking the premise language to the conclusion idea, or an answer ruling out an alternate hypothesis for why the book has inconsistencies.

8.

The conclusion cited does not follow unless

  1. authors generally try to reconcile

    Opposite (if anything)

    This argument is only about this one book, so our author doesn't need to assume anything about what authors generally do. But even if we got past that, this goes against our author's thinking. She is saying this book used multiple sources and ended up with inconsistencies as a result, so this author seemingly did NOT reconcile the different sources.

    12% picked this

  2. the inconsistencies would be apparent

    Out of Scope: average reader

    The author isn't making any assumptions about "the average reader". It doesn't matter whether these inconsistencies are obvious only to scholars or whether most of us average readers would notice them. We only care about what caused them.

    4% picked this

  3. Correct

    the history book’s author used

    Why this is right

    Since this has the lovable "ruling-out" language (no / not) that we associate with correct Defender-style answers on Necessary Assumption, it's worth slowing down, negating this, and seeing whether it weakens. The negation would be saying that the book's author DID use a source that contained inconsistencies repeated in the author's book. This would weaken by presenting an alternate explanation for why the book has inconsistencies: it's not that the book's writer used multiple sources; rather, it's because the book's writer used one source, which itself had multiple inconsistencies.

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

    61% picked this

  4. the author of the history

    Out of Scope (author's awareness)

    The author's awareness of the Effect (inconsistencies) has nothing to do with whether that Effect is attributable to "multiple sources" or some other reason. We don't have to think the author was aware of these inconsistencies in order to believe the hypothesis that the inconsistencies arose from using multiple sources.

    12% picked this

  5. the author of the history

    Too Strong: all

    This hypothesis certainly doesn't need to think that the author was familiar with 100% of available source material. If we negated this and said the author was only familiar with 99% of the available source material, that wouldn't hurt the hypothesis at all.

    11% picked this

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