Logical Reasoning

PT151 · S2 · Q23 A gram of the artificial sweetener

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A gram of the artificial sweetener aspartame is much sweeter than a gram of sugar.

Evidence

1g of aspartame > 1g of sugar Sweeter

Soda w/ sugar = sweet.

Intermediate Conclusion

soda w/ aspartame > soda w/ sugar Sweeter

Conclusion

Drinking sodas w/ aspartame will cause you to have an extreme preference for sweet things.

Evaluation

Because the author draws an Intermediate Conclusion with "so" and then her ultimate conclusion with "Thus", we need to think through both moves here.

If each gram of aspartame is sweeter than each gram of sugar, does that mean sodas with aspartame are sweeter than sodas with sugar?

Not necessarily — who said that we're using an equal number of grams? Maybe sodas with aspartame use 3g of aspartame, but sodas with sugar use 20g of sugar.

What about the next move -- if we accepted that aspartame sodas are sweeter, do we have to accept that someone who drinks them will develop a preference for extremely sweetened things?

Not necessarily — maybe they only like their sodas sweet. maybe the sweetness of their aspartame sodas actually turns them off from other sweetened stuff. maybe they don't even like the sweetness of the aspartame soda but they tolerate it because they have different reasons for wanting to drink that soda.

Goal

Premise Ingredient 1 has more of property A, per unit, than does Ingredient 2.

Intermediate Conclusion Something with ingredient 1 has more of property A than something with ingredient 2.

Main Conclusion If you have something with ingredient 1, you'll develop a preference for lots of property A.

23.

Which one of the following arguments exhibits flawed reasoning that is most similar to flawed reasoning in the argument above?

  1. People sometimes develop a preference

    Bad Premise Match

    There aren't any details in the premise about "ingredient 1 has more of property A, per unit, then ingredient 2", so I'd move on.

    5% picked this

  2. Most people own more books

    Weak Logic Match

    We could say that "Books have more Property A than TV Shows", if we thought of Property A as "time-consuming". To mimic the author's move to Intermediate Conclusion, though, we'd need to say "Something containing books is more time-consuming than something containing TV shows". If we had said, "Thus it would take someone longer to read all the books in their study than to watch all the shows in their Netflix queue", it would be replicating the flaw of, "Wait a sec --- how many books are in the study vs. how many shows are in the Netflix queue?" Instead, this is about how many books people own vs. how many televisions they own.

    20% picked this

  3. Correct

    Joe’s piggy bank has only

    Why this is right

    This is a tough correct answer because it only deals with the author's flaw in drawing her subsidiary conclusion. It never gets into the final conclusion. Nickels have more of property A (monetary value) than pennies do. Thus, something with nickels (Maria's bank) has more property A than something with pennies (Joe's bank). This is vulnerable to the same objection we had with the original argument: how many grams of aspartame are in an aspartame soda vs. how many grams of sugar are in a sugary soda? = how many nickels are in Maria's bank vs. how many pennies are in Joe's bank?

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

    53% picked this

  4. Stephanie likes hot summer weather

    Inverts Premise And Conclusion

    The original argument went from a Premise about exposure to sweetness to a Conclusion about developing a preference for sweetness. This argument reverses that and goes from a Premise about preference to a Conclusion about exposure.

    17% picked this

  5. Guillermo has a much shorter

    Bad Conclusion Match

    The conclusion is about making an estimate; it's hard to see how that would match either of the two conclusions. We could say that Guillermo's commute has less of property X (drive time) than Abdul's commute does. But then we would need a move that is saying "something with Guillermo's commute in it has more property X than something with Abdul's commute in it". For example, "Thus, Guillermo spends more time commuting each week than Abdul does", to which we might object, "Wait a sec — how many days a week does Guillermo vs. Abdul go to work?"

    5% picked this

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