PrepTest 119, Section 3, Question 19
Tanya would refrain from littering if everyone else(15 more words not shown)
Which one of the following(13 more words not shown)
- AAll residents of(31 more words not shown)
- BIf a talented(42 more words not shown)
- CHerbert will stop(31 more words not shown)
- DIf all whales(23 more words not shown)
- EIf all of(29 more words not shown)
Reading the argument
Tanya's friends aren't everyone. We know what she would do if everyone else stopped littering. We haven't been told that the whole world has stopped just because her friends have.
Tanya might refrain anyway. Maybe she simply doesn't like littering. The problem isn't that the conclusion must be false; it's that this rule doesn't establish it from the facts given. The author substitutes a smaller group for the whole group named in the condition and then claims the promised result.
What we’re looking for
For the parallel flaw, keep both pieces in view: a rule about an entire group, followed by evidence about a limited part of that group. The conclusion should still claim the result the original rule promised. Some choices also switch from a large group to a small one but make an additional, different move between the rule's starting point and its result.
Working the answers
- A
Having some shared goals doesn't establish that the specific park goal is shared beyond the group requesting improvements. The residents could agree about something else. That is a mismatch between unspecified common goals and a particular goal, not applying a rule requiring everyone to do something after hearing only about a subset.
- B
The rule says what friends should do when an artist is talented and willing to starve. The conclusion instead tries to establish the artist's talent from willingness to starve and the friends' respect. Their respect might have some other basis. Unlike the original, the conclusion isn't the result promised by the rule; it works back toward one of the starting requirements.
- C
Herbert's rule leads to stopping sales. But C's conclusion only concerns whether some customers will complain. It never uses the smaller group's silence to conclude that Herbert will stop selling office supplies. That latter conclusion would get closer to Tanya's mistake. As written, C doesn't make the required move to the rule's promised result.
- D
The rule runs from whales needing air to whales being easy to observe. The conclusion runs back from easy observation to needing air. There is a shift to blue whales too, but matching that group shift alone isn't enough. Tanya's argument claims the rule's original result; D uses the result to try to establish what would produce it.
- ECorrect
All the restaurant's customers liking its food corresponds to everyone else refraining from littering. Only the people Sherryl consulted liking it corresponds to only Tanya's friends refraining. An exceptional restaurant is the promised result, just as Tanya not littering is the original promised result.
Sherryl may not have consulted every customer. Evidence from those particular people therefore doesn't establish the all-customers condition. E keeps the same kind of result while substituting a limited group for the whole group needed to trigger the rule. That's the full pattern, not just a shared word like all.
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