Logical Reasoning

PT11 · S2 · Q17 Of the two proposals for solving

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Of the two proposals for solving the traffic problems on Main Street, Chen’s plan is better for the city as a whole, as is clear from the fact that the principal supporter of Ripley’s plan is Smith Stores.

Conclusion

Chen's plan is better for the city as a whole than Ripley's.

Evidence (as is clear from the fact)

The principal supporter of Ripley's plan is Smith Stores, which knows where its own interest lies and has, in the past, pursued its own interests even when doing so harmed the city as a whole.

Evaluate

The author is trying to evaluate which plan is better for solving traffic problems, but her evidence doesn't involve any analysis on how each plan would attempt to solve traffic problems.

Instead, her evidence is irrelevantly about who SUPPORTS one of the plans. We're supposed to be evaluating the merits of these two plans, not talking about who their proponents are.

When an author discusses the source of an idea rather than the idea itself, they're committing the famous Ad Hominem flaw.

This usually feels like an author saying,

Here, the author is citing both! We can dismiss Ripley's plan because someone who supports Ripley's plan (Smith Stores) is acting out of self-interest and has in the past acted in ways that were bad for the city.

Goal

Find an answer committing the Ad Hominem flaw. The answer would get extra similarity points if it were comparing two plans and if it were rejecting one of them because a proponent has self-interested motives and conflicting past behavior.

But the essence of the flaw is that the author is rejecting an idea because of its source/backers rather than engaging with the idea itself.

17.

The faulty reasoning in which one of the following is most parallel to that in the argument above?

  1. Surely Centreville should oppose adoption

    Bad Match

    This argument says Centreville should oppose the plan because the plan is not in Centreville's interest. There's no claim about who is supporting or opposing the plan, and no inference from the bad motives of a sponsor. The original argument's flaw is "the principal supporter is self-interested, so the plan is bad" — this answer doesn't do that.

    2% picked this

  2. The school board should support

    Bad Match

    This is almost an Ad Hominem in reverse, saying we should PICK a plan because the source/supporter is good. This argument supports a plan because the source is well-qualified (there's nothing wrong with that). It's definitely flawed to think, "if we spent a bunch of money on this advice, we should take the advice", but that's nothing like the flaw in the original argument.

    3% picked this

  3. Of the two budget proposals,

    Bad Match

    This argument compares the two budget proposals on their content: the mayor's "addresses the needs of the city as a whole," whereas the city council is "protecting special interests." It evaluates what each proposal actually does, not the motives of its supporters. The original argument never describes what Chen's or Ripley's plan actually proposes; it argues entirely from the backer's motives.

    33% picked this

  4. Nomura is clearly a better

    Bad Match

    This argument endorses Nomura based on pretty respectable reasons. The three people who best know the demands of the job and who are most affected by whoever gets this job all support the same candidate.

    6% picked this

  5. Correct

    The planned light-rail system will

    Why this is right

    This re-creates the Ad Hominem flaw. Rather than addressing the merits of the planned light-rail system, the author favors the "let's have it" view over the "let's not have it" view, because the main supporter of the latter view is an entity acting out of self-interest and having troublesome past behavior.

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

    56% picked this

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