Logical Reasoning

PT126 · S3 · Q7 Scientist: In our study, chemical R

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Scientist: In our study, chemical R did not cause cancer in laboratory rats.

Conclusion

We can’t conclude from this study that R is safe for humans.

Evidence

In the study R didn’t cause cancer in rats, but many substances known to cause cancer in humans don’t cause cancer in rats (probably because a rat’s life span isn’t long enough for the carcinogenic effect to materialize).

Evaluation

Our conclusion is the 2nd sentence. Since we pivot into that conclusion with a “But”, we know that the previous idea was some sort of counterpoint. The first sentence is potentially evidence for the idea that “R is safe for humans”. The author makes an argument to resist making this hasty leap in logic.

Goal

We want something like counterpoint, or a fact that the author says is not grounds for making some other inference.

7.

Which one of the following most precisely describes the role played in the scientist's argument by the statement that chemical R did not cause cancer in laboratory rats?

  1. It is cited as evidence

    Opposite

    This sentence would be evidence for the idea that R is safe for humans.

    2% picked this

  2. It is advanced to support

    Bad Conclusion Match

    The third sentence is advanced to support the contention that test results about rats cannot always / cannot immediately be extrapolated to humans. The first sentence is just a test result. The author brings it up because she knows that it will tempt people into extrapolating to humans.

    14% picked this

  3. It illustrates the claim that

    Trap

    Unmentioned / Out of Scope: “too short to be suitable” There is no claim that rats live too short to be suitable test subjects. We might make that inference upon reading the final claim in the argument, but the argument never makes that claim.

    4% picked this

  4. It is used as evidence

    Opposite

    This claim would be evidence for the idea that R does not cause cancer in humans. Other claims in the argument help us realize that this first claim doesn’t prove R is safe for humans, but this claim isn’t supporting the hypothesis that R causes cancer in humans.

    2% picked this

  5. Correct

    It is cited as being

    Why this is right

    Our author’s conclusion says about this claim that “we cannot conclude from [this claim] that R is safe for humans”. So, yes, this claim was cited as being insufficient to support a conclusion that R is safe for humans. This is the only answer that correctly avoids premise language (it supports / it’s evidence / it illustrates) and gives us counterpoint language (it is cited as insufficient).

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

    78% picked this

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