PrepTest 158, Section 4, Question 26
Every Labrador retriever in my neighborhood is a(33 more words not shown)
The flawed reasoning in which(16 more words not shown)
- AAll the students(36 more words not shown)
- BWhenever it snows(37 more words not shown)
- CEvery musician I(32 more words not shown)
- DAll of the(30 more words not shown)
- EAll of the(49 more words not shown)
Reading the argument
Why can't training and genetics both matter?
These Labradors are well behaved, and the passage tells us that no pet would behave well without training. So the dogs must have been trained. But needing training doesn't mean training explains everything. Imagine, purely as a way of thinking about it, that training contributed 10 percent and the dogs' inherited traits contributed 90 percent. Training could still be essential even if another factor contributed more. We aren't given actual percentages; the example shows why “required” doesn't mean “the whole explanation.”
What we’re looking for
For the parallel-flaw question, look for an argument that identifies a required factor, then uses that requirement to dismiss another possible contributor. Here, training is required for the good behavior, and the author wrongly treats that as a reason to exclude the breed's genetics. We need those roles, not just an answer mentioning two possible causes.
Working the answers
- A
The opening is close. Successful students correspond to the well-behaved dogs, and good teachers correspond to the training required for that success. But the conclusion recommends hiring good teachers. It doesn't say that teachers explain the success while some other contributor, such as the students' home circumstances, does not. A leaves out the exclusion that makes the original flawed.
- BCorrect
Snowy conditions are associated with more crashes, just as these Labradors are associated with good behavior. The argument then says carelessness is required for crashes, paralleling the claim that training is required for good behavior.
The conclusion makes the same mistake: because carelessness is required, icy roads supposedly aren't a cause. Why couldn't both matter? A careless driver's mistake might become a crash because the road is icy. Carelessness being necessary wouldn't make the ice irrelevant.
The reference to icy roads fits the snow already mentioned, just as the original's reference to genetic makeup fits the Labrador breed already mentioned. We don't need a completely new topic in the conclusion; we need the same unsupported exclusion of a possible contributor.
- C
This compares good dancers who are musicians with bad dancers who are mathematicians. It doesn't state that a particular factor is required for good dancing and then wrongly treat that requirement as ruling out another cause. Its contrast between two groups is a different route to its conclusion.
- D
The premise already describes good cooks as using butter, and the conclusion tells a prospective good cook to use butter. Whatever concerns we might have about extending the country's pattern, there is no move from a required factor to a claim that it alone explains the outcome. The original's central mistake is missing.
- E
These students get A's despite lacking a skill needed for an adequate understanding of algebra. The conclusion uses that lack to question whether good work explains their grades. The original doesn't establish that the Labradors lack a required ability. It establishes that they have the required training, then wrongly excludes genetics. Those are different structures.
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