Logical Reasoning

PT155 · S1 · Q8 A person who does not have

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A person who does not have both a high school diploma and a demonstrated competence in the techniques of cardiopulmonary resuscitation will not be licensed as an emergency medical technician.

Conclusion

Marie will be licensed as an emergency medical technician.

Evidence (since)

Marie has a high school diploma and a demonstrated competence in CPR.

A person who doesn't have a high school diploma and doesn't have demonstrated competence in CPR will not be licensed as an emergency medical technician.

Evaluate

Whenever we do Parallel Flaw, we listen a little extra hard for the top 6 famous flaws (Nec vs. Suff, Part vs. Whole, Unproven vs. Proven False, Sampling, Ad Hominem, Causal).

This argument is committing a Necessary vs. Sufficient flaw, meaning the argument provides a conditional logic premise and then the author interprets it in an illegal reversed or negated fashion. Since the flaw here is related to conditional logic, it makes sense to try to get an abstract recipe for the argument.

Conditional Premise No Diploma Not be or → Licensed ~A or ~B → ~C No Comp in CPR as EMT

Factual Premise Mary = Diploma, Comp in CPR X is A and B.

Factual Conclusion Mary = Licensed as EMT X is C.

Goal

With conditionals, we're never allowed to just "flip the lightswitch" on the ideas. We can say . That doesn't mean we're saying .

We're looking for this structure Prem 1: ~A or ~B → ~C Prem 2: X is A and B. Conc: X is C.

But we could settle for an Illegal Negation, even if it didn't match that exact structure.

We just need a conditional, and then a Premise to Conclusion move that works by illegally negating that conditional.

8.

Which one of the following contains flawed reasoning that most closely parallels the flawed reasoning in the argument above?

  1. Without having either an excellent

    Different Flaw

    This argument is flawed, but not because it did an illegal negation. It argues via the contrapositive, which is legal. It just messes up by saying AND in the conclusion, rather than OR. ~Excellent ear Can't play and → piano well ~Exceptional dexterity The contrapositive here is Can play well → Excellent Ear or Excellent Dexterity So when we learn Paul plays well, we can infer he has a good ear, good dexterity, or both. The actual conclusion is overconfidently thinking he has both, but that's not the same as an illegal negation.

    7% picked this

  2. Correct

    It is not possible to

    Why this is right

    We have a conditional premise, Not fluent in at least → Can't be an effective two languages foreign language teacher The author then reasons via an illegal negation, thinking "If the opposite of the trigger is true, then the opposite of the outcome is true". Professor Y is fluent in at least two languages. Thus, she will be an effective foreign language teacher. This was structurally different in the sense that the original argument used a conditional with an "and" in the trigger, and this one doesn't have a compound trigger. But it's still the same flaw; the author is assuming that when you have a rule like "X → Y" that if the trigger is not happening then the outcome is not happening. Had there been an answer that replicated the Illegal Negation and replicated the structural feature of a conditional with an "and" in the trigger, then we would definitely prefer that one. But replicating the flaw is the most important part of Parallel Flaw.

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

    79% picked this

  3. A person cannot be a

    Valid Logic

    This provides a conditional: Licensed plumbing → Completed contractor apprenticeship Then it says Martin meets the trigger and correctly concludes that Martin meets the outcome.

    4% picked this

  4. No one can be an

    Different Flaw

    This provides a conditional: Effective mayor → Thorough knowledge of major ind. seaport of nat'l / int'l affiars The factual premise mostly matches the trigger and the conclusion matches the outcome. The only glitch in this argument is that we aren't sure if Mayor Leroux is mayor of a major industrial seaport. So the trigger was not fully established. That's a different flaw from the original, in which the premise was establishing the Trigger isn't true and then concluding the Outcome isn't true.

    9% picked this

  5. The only way to make

    Valid Logic

    This provides a conditional: Delicious veggie soup → Fresh veggies Then it factually establishes the trigger is happening (this veggie soup is delish) and then correctly concludes the outcome (this soup was made with fresh veggies).

    1% picked this

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