Logical Reasoning

PT119 · S4 · Q6 Skeletal remains of early humans

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Skeletal remains of early humans indicate clearly that our ancestors had fewer dental problems than we have.

Conclusion (So)

The diet of early humans was most likely very different from ours.

Evidence

Skeletal remains of early humans indicate that our ancestors had fewer dental problems than we have.

Evaluate

This evidence presents an Asymmetric Comparison (aka a "Curious Fact"):

early humans had fewer dental problems than we have

The conclusion assumes a Causal Explanation for that fact:

the reason we modern humans have more dental problems is because of what food is in our diet; the reason early humans had fewer dental problems is because of what food was in their diet.

Whenever we have this Explain Curious Fact type argument, there are two pressure points:

1. Alternate Explanations for the Curious Fact (what else could be the reason that early humans had fewer dental problems than we have?)

2. the Plausibility of the Author's Explanation (is there any evidence that the diet of early humans was different from ours? any evidence that their diet was better for teeth?)

Goal

Since we're strengthening, we either want an answer to rule out an alternate way to explain why early humans had fewer dental problems, or we want to increase the plausibility of the theory that they had fewer dental problems because of having a different diet.

6.

Which one of the following, if true, most strengthens the argument?

  1. A healthy diet leads to

    Unclear Impact

    It's hard to know whether this strengthens or weakens the plausibility of the author's explanation, because we don't know whether early humans had a healthier diet than modern humans do. The author is only saying it's "different", not that it's necessarily better or healthier.

    8% picked this

  2. Skeletal remains indicate that some

    No Impact

    On the face of this, it feels more like a weakener because it's talking about early humans having dental problems. In reality, it doesn't weaken because the evidence was just saying "on average" early humans had fewer dental problems. It's not saying that early humans never had cavities. But either way, this definitely doesn't strengthen.

    0% picked this

  3. The diet of early humans

    Mixed Impact

    This answer could potentially weaken because it's making the diet of early humans seem more comparable to that of modern humans: "their diet was at least as varied as ours" If we knew that their diet was WAY more varied than ours, then that would strengthen the idea that their diet was different from ours. But this just says it was "at least as varied" as ours, so they could be tied with ours, and thus comparable, which would go against the conclusion.

    4% picked this

  4. Early humans had a shorter

    Weakens

    This weakens by suggesting an Alternate Explanation for why early humans had fewer dental problems: they didn't live long enough to develop dental problems, which typically show up late in life.

    4% picked this

  5. Correct

    Diet is by far the

    Why this is right

    This strengthens the plausibility of the author's explanation that since there was a difference in dental problems between early humans and modern humans, there must be a different in diet. After all, the #1 most significant factor that affects whether you have dental problems is diet.

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

    83% picked this

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