Logical Reasoning

PT11 · S2 · Q25 The fact that tobacco smoke

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The fact that tobacco smoke inhaled by smokers harms the smokers does not prove that the much smaller amount of tobacco smoke inhaled by nonsmokers who share living space with smokers harms the nonsmokers to some degree.

Conclusion

The fact that tobacco smoke harms smokers does not prove that a much smaller amount of tobacco smoke harms nonsmokers to some degree.

Evidence

Many substances (e.g., vitamin A) are toxic in large quantities but beneficial in small quantities — so "harmful in large amounts" doesn't entail "harmful in small amounts." It might even reverse to "beneficial."

Pattern

Large quantity of X → bad. But it doesn't follow that small quantity of X → bad. Supporting example: another substance where large amounts are bad and small amounts are beneficial (a reversal).

Goal

Find an answer where: (1) large amount = bad, (2) we can't conclude small amount = bad, (3) supported by an example where small amounts are actually beneficial.

25.

In which one of the following is the pattern of reasoning most similar to that in the argument above?

  1. The fact that a large

    Bad Match

    This argument lacks the key reversal. The supporting example says a small amount of bleach has effects "too slight to change the color of the fabric" — i.e., a smaller version of the same effect, not a beneficial reversal. The original used vitamin A as a substance where small amounts flip from harm to benefit. Without the flip, this is a different pattern.

    16% picked this

  2. Although a healthful diet should

    Bad Match

    This argues that more isn't always better — a different shape. The original concluded that less doesn't necessarily preserve the same effect. This goes the other way: questioning whether more is healthier rather than whether less is harmful. Wrong direction.

    7% picked this

  3. The fact that large amounts

    Bad Match

    This concludes that fertilizers aren't generally harmful — a sweeping defense of the substance. The original concludes only that small amounts might not be harmful (without claiming the substance is generally fine). The conclusions are at different strengths.

    6% picked this

  4. From the fact that five

    Bad Match

    This argues from some people's positive reaction that not everyone will react the same way — a generalization-from-sample issue. The original is about dose-response (large vs. small amounts), not about variation among people. Different pattern.

    7% picked this

  5. Correct

    Although watching television for half

    Why this is right

    This matches all three pieces. (1) Large amount of TV (half the day) = bad (a waste). (2) That doesn't prove a small amount of TV is even a small waste. (3) Supporting example: sleep — half the day of sleeping is a waste, but some sleep is positively necessary (a beneficial reversal). The same dose-response flip as vitamin A. Identical structure to the original.

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

    65% picked this

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