Logical ReasoningDifficulty: Hard

PT14 S2 Q10 Explanation

The government of Penglai, an

A free, expert breakdown of this official LSAT Logical Reasoning question.

TopicsFlaw

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Stimulus

The government of Penglai, an isolated island, proposed eliminating outdoor advertising except for small signs of standard shape that identify places of business. Some island merchants protested that the law would reduce the overall volume of business in Penglai, pointing to a report done by the government indicating that in had a larger market share than those that did not.

What this question is testing

Flaw

Your task

Describe the reasoning error the argument actually commits.

Common trap

Answers that name a real logical flaw the argument doesn't actually make.

Winning move

Articulate the gap in the reasoning yourself, then match it to the choice that describes that gap.

Reading along? Open the full official question in LawHub — we show a fragment here and keep the reasoning in our own words.

The question
10.

Which one of the following describes an error of reasoning in the

Answer choices

  1. Too Strong: no good reasons4% picked this

    presupposing that there are no good reasons for restricting the use of outdoor

    Presupposing = takes for granted = assumes, like in Necessary Assumption. Did the merchants have to assume that there are zero good reasons to restrict outdoor advertising? Not at all. They could easily accept that there is at least one good reason to restrict outdoor advertising, while still lamenting that doing so would reduce the overall volume of business in Penglai.

  2. Correct53% picked this

    assuming without giving justification that the outdoor advertising increased market share by some means other than by diverting

    Why this is right

    This is also presenting a supposed Necessary Assumption. Do the merchants need to assume that outdoor advertising increases market share by some means other than by diverting trade from competing businesses? That's a mouthful. Let's see if negating this answer would weaken: Outdoor advertising only increases market share by diverting trade from competing businesses That does weaken, but it's not likely to 'click' for most people, unless they picked up on a weirdness to the argument (unrelated to the Famous correlation = causation flaw). Penglai, we are told, is an isolated island. Some people live there and probably don't leave much, since it's expensive to go back and forth to an isolated island. Some people may travel there for vacation. The merchants' conclusion is worried about the "overall volume of business" that gets done in Penglai. Maybe in 2020, $2 billion worth of transactions occurred. How would eliminating outdoor advertising change that? If you live on the island, you're still spending the same amount of your income on necessities and luxuries, whether businesses have an outdoor ad or not. If you're a tourist visiting, you're still spending the same amount of your vacation budget there. You showed up ready to blow $1000 during your week in Penglai. That's the volume of business you're creating. If there are outdoor ads for certain places, you might be more likely to spend your money at that restaurant rather than at some other restaurant that doesn't have an outdoor ad, but if we take away these outdoor ads, you're still going out to dinner at some restaurant. The idea is that outdoor ads are more likely to affect where you spend your money than they are to affect whether you spend your money. The merchants are acting like if there aren't outdoor ads, then people just won't take out their wallet as much. When we negate the assumption in this answer choice, we are objecting, "What are you talking about? Sure, outdoor ads can help a business gain bigger market share. But that's not be cause outdoor ads create sales that wouldn't otherwise exist. The same volume of money is going to be spent either way. Outdoor ads just funnel money more towards the advertised businesses than towards non-advertised businesses."

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

  3. Not an Objection2% picked this

    ignoring the question of whether the government’s survey of the island

    Yes, the author fails to address whether the survey of the island could really be objective. But is that really our complaint with the merchants' logic? That sounds more like we're just attacking the validity of their premise. Moreover, we have no reason to think that this survey might be subjective, biased, or skewed. The survey is collecting very objective, quantifiable data: - do you / don't you use outdoor ads - what is your market share

  4. Too Strong: precisely proportionate40% picked this

    failing to establish whether the market-share advantage enjoyed by businesses employing outdoor advertising was precisely proportionate to

    Fails to establish = takes for granted = presumes = Necessary Assumption answers. Did the merchant need to assume that the market-share advantage by businesses that do outdoor advertising was precisely proportional to the amount of advertising? i.e. did they need to assume that if business X does 17% more outdoor advertising than business Y, then business X will have precisely 17% more market share? Of course not. That's a completely unrealistic expectation. The merchants just think that the outdoor ads have some causal impact on market share. They don't need to think that it's precisely 1:1.

  5. Not an Objection0% picked this

    disregarding the possibility that the government’s proposed restrictions

    When we see fails to consider / ignores the possibility, then we ask ourselves whether the idea that follows would be a Weakening objection. Can we hurt the merchants' argument by saying, "Yo -- the proposed restrictions are unconstitutional"? No. That has no effect on the claim that "the proposed restrictions will reduce overall volume of business". Whether or not something is constitutional is a totally separate issue from whether or not that something would have an effect on overall volume of business.

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