A person who does not have

Answer choices

1. A

   Different Flaw7% picked this

   Without having either an excellent ear for music or exceptional manual dexterity, a person cannot play the piano well. Since Paul plays piano extremely

   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%
2. B

   Correct78% picked this

   It is not possible to be an effective foreign language teacher without being fluent in at least two languages. Since Professor Yessios is fluent

   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.

   78%
3. C

   Valid Logic4% picked this

   A person cannot be a licensed plumbing contractor without having completed an apprenticeship. Since Martin is a licensed plumber,

   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%
4. D

   Different Flaw10% picked this

   No one can be an effective mayor of a major industrial seaport without a thorough knowledge of both national and international affairs. The fact

   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.

   10%
5. E

   Valid Logic2% picked this

   The only way to make a delicious vegetable soup is to use fresh vegetables. Since this vegetable soup is delicious, it must

   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).

   2%