PrepTest 107, Section 1, Question 23
Linda says that, as a scientist, she knows(22 more words not shown)
Which one of the following(11 more words not shown)
- ARalph says that,(33 more words not shown)
- BFranz says that,(40 more words not shown)
- CYuri says that,(48 more words not shown)
- DXi says that,(41 more words not shown)
- EBetty says that,(34 more words not shown)
Reading the argument
Being a scientist doesn't make Linda the spokesperson for every scientist. She might dislike poetry, but how does her own membership in the group establish what everyone else appreciates?
There is another problem even if we accept her claim about scientists. Most scientists are logical, and no scientists appreciate poetry. What does that tell us about whether poetry lovers are logical? Nothing. Maybe every poetry lover is logical too. Both groups could be logical even though only one appreciates poetry.
What we’re looking for
For a parallel flaw, keep both moves in view. First, someone uses membership in a group to speak for that whole group. Second, the argument describes most members of that group one way, then gives some people outside it the opposite description. Here we move from logical scientists to illogical poetry lovers without evidence about those poetry lovers. A choice needs to match that change, not just start with a person claiming expertise.
Working the answers
- A
Ralph is a biology expert making a claim about marsupials. He isn't using his own membership among biology experts to declare what every biology expert likes or thinks. The later reasoning also differs: if most marsupials are native to Australia and none lays eggs, some Australian animals are marsupials that do not lay eggs. That conclusion follows from the stated premises. It doesn't jump to an unsupported description of the opposite group.
- BCorrect
Franz speaks for all fathers because he is a father, just as Linda speaks for all scientists because she is a scientist. Not wanting children to eat candy at bedtime matches not appreciating poetry. Being an adult matches being logical.
Now watch the conclusion: some people who do want children to eat candy at bedtime are children. That gives members of the other preference group the opposite description—children rather than adults, just as Linda gives poetry lovers the description illogical rather than logical. But those candy supporters might all be adults. Facts about fathers don't establish the conclusion about them. Both moves line up.
- C
Yuri makes a claim about wine quality, not about the beliefs of every wine connoisseur. To match Linda's opening move, he'd need to use being a connoisseur as his basis for speaking for that entire group. The rest of C compares categories of wine and their quality; it doesn't conclude that people with the opposite preference have the opposite personal characteristic.
- D
Xi's photography experience supports a claim about film rather than a claim about what all photographers appreciate. The later conclusion identifies some instant film that is color film and therefore less sharp than the best black-and-white film. It stays with the overlap the premises supply, rather than assigning an opposite characteristic to a new group.
- E
This is the closest competitor. Betty does speak for all corporate executives because she is one. And E moves from executives who dislike paying taxes to people who like paying taxes.
But the description stays honest. Linda moves from logical scientists to illogical poetry lovers. To make the same move, E would need to conclude that some people who like paying taxes are dishonest. E's conclusion is unsupported too, but it makes a different jump. We need the same mistake, not merely another bad argument.
More Parallel Flaw questions
Learn the LSAT our way
Our platform drills Parallel Flaw questions at your level and adjusts as you improve.