Logical Reasoning

PT137 · S2 · Q9 To use the pool at City Gym

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To use the pool at City Gym, one must have a membership there.

Conclusion

Sarah must use the pool at City Gym at least sometimes.

Evidence

To use that pool you have to have a membership to City Gym, and Sarah has a membership to City Gym.

Evaluate

Those of us who have been members of fitness clubs probably know that just because you pay for a membership doesn't mean you use all the stuff at the fitness club.

Maybe Sarah just goes for free weights and yoga and never uses the pool.

So conversationally, our objection might sound like,

But since we have conditional logic (to do X, you must Y) and this is Flaw, we should consider whether this is the famous Necessary vs. Sufficient flaw, in which an author presents a conditional relationship and then applies it using illegal backwards or opposite logic.

The author presents a conditional: Use Pool at CG → Membership

Then he illicitly argues, Since Sarah has Membership, Sarah Use Pool

That's applying the conditional rule in an illegal backwards fashion, in other words, confusing the Sufficient and Necessary conditions.

Goal

Look for a Necessary vs. Sufficient answer or one pointing out that Sarah might a membership but not use the pool.

9.

The reasoning in the argument is flawed in that the argument

  1. mistakes a policy that is

    Bad Match

    Do we have a policy that is strictly enforced? Hmm, not really. We have a policy -- "to use pool, you must have a membership", but we don't know how strictly it's enforced. We might be able to confidently walk in, and the only I.D. we need to flash is our pearly white grin. We certainly never talked about people making exceptions to this policy and letting non-membership holders swim there.

    1% picked this

  2. Correct

    treats a statement whose truth

    Why this is right

    This is a statement: Sarah has a membership The conclusion is Sarah uses the pool. For Sarah uses the pool to be true Sarah has a membership is required. However, our author it treating this statement, Sarah has a membership as though it ensures that Sarah uses the pool. Everything matches. If we knew to look for the Necessary vs. Sufficient flaw, then we would see the synonyms here and think, "Required vs. Ensures" is the same as Necessary vs. Sufficient.

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

    81% picked this

  3. presumes that one or the

    Wrong Flaw

    This answer describes the semi-famous flaw False Choice, in which the author lays out some options and acts like they're the only options without ever establishing that. This argument isn't laying out two alternatives. We could pretend that these are two alternatives: "Sarah never uses the pool" vs. "Sarah at least sometimes uses the pool" But in that case, we wouldn't complain that the author was failing to consider that a 3rd alternative may exist. There's no 3rd alternative, if the first two are binary: She uses the pool / she doesn't use the pool False Choice doesn't mean "you made an arbitrary choice between True and False." It means, "you acted like X and Y were our only options, but there might be more options."

    5% picked this

  4. concludes that a person has

    Bad Premise Match

    Does the conclusion say a person has a certain attribute? Sure, we could say "Sarah" has the attribute of "sometimes swims at City Gym". Is there a premise that says Sarah is part of a group, most of whom sometimes swim at City Gym? No, the premises are Sarah has a membership, and you need a membership to swim.

    12% picked this

  5. draws a conclusion that merely

    Wrong Flaw

    This describes the famous Circular Reasoning flaw, in which the Evidence assumes or restates the Conclusion. This answer is almost always wrong, and if you see more than one unique premise, it's definitely wrong. The premises are "Sarah has membership" and "pool requires membership". The conclusion is "Sarah uses pool". No claims were restated. All three were distinct.

    1% picked this

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