All the evidence so far

Answer choices

1. A

   Bad Conclusion Match17% picked this

   David and Jane both think they know how to distinguish beech trees from elms, but when they look at trees together they often disagree.

   Without even reading the whole answer, we can peek at the conclusion and see it's a poor match for the original. The original conclusion is, "One will be right, and one will be wrong", which is why we have our objection of, "Wait ... couldn't they both be wrong?" But we couldn't make that objection to this conclusion, because saying "at least one of them is wrong" is allowing for the possibility that they're both wrong.

   17%
2. B

   Bad Conclusion Match5% picked this

   Although David thinks the tree they saw was a beech, Jane thinks it was an elm. Jane’s description of the tree’s features is consistent

   Without reading the whole answer, we can peek at the conclusion and see it's a poor match for the original. The original conclusion is, "One will be right, and one will be wrong", which is why we have our objection of, "Wait ... couldn't they both be wrong?" This conclusion isn't saying anything about right / wrong, or correct / incorrect. It's just concluding, "so, this prediction is incompatible with that prediction". That's a match for our premise, not for the conclusion.

   5%
3. C

   Bad Conclusion Match10% picked this

   David and Jane have been equally good at identifying trees so far. But David says this one is an elm, whereas Jane is unsure.

   This conclusion is a conditional claim, "If elm, then David is more right". The original conclusion is, "One will be right, and one will be wrong". It wasn't conditional, and it didn't favor either of the two parties.

   10%
4. D

   Weak Conclusion Match12% picked this

   David thinks that there are more beeches than elms in this forest. Jane thinks he is wrong. The section of forest we examined was

   This conclusion is saying, "We'll find out whether this one person was right or wrong." The original conclusion is, "One person will be right, and the other person will be wrong", which is why we have our objection of, "Wait ... couldn't they both be wrong?" But we couldn't make that objection to this conclusion, because saying "couldn't David be both right and wrong?" is a silly objection. Given that Jane's position is "David is wrong", it is fair to say that finding out David is right or wrong does simultaneously tell us whether Jane was right or wrong (her correctness is inverse to his). But again, the objection of "couldn't they both be wrong" does not apply, because there are binary options. David is right, and thus Jane was wrong. or David is wrong, and thus Jane was right. It's impossible for David to be wrong and thus Jane to also be wrong.

   12%
5. E

   Correct55% picked this

   David thinks this tree is a beech. Jane thinks it is an elm. Maria, unlike David or Jane, is expert at tree identification, so

   Why this is right

   This conclusion, like the original, is saying that an upcoming measurement / test / evaluation will show that one person was right and one was wrong. David and Jenn have incompatible predictions, just as Dr. Grippen and Professor Heissmann had. Those predictions will be put to the test by an upcoming thing (either Maria's expert analysis or the results of a planned experiment). The argument is fallaciously concluding that one person will be vindicated and the other person shot down, but in both cases we can make the objection, "Couldn't it turn out that both parties are wrong?" Maybe Maria is going to tell us that this tree was neither beech, nor elm. Maybe the results of the planned experiment will not match Dr. Grippen's or Professor Heissmann's predictions.

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

   55%