PrepTest 114, Section 4, Question 18
Anders: The physical structure of the brain plays(97 more words not shown)
The statement "thinking machines closely(19 more words not shown)
- Athe main conclusion(3 more words not shown)
- Ba subsidiary conclusion(7 more words not shown)
- Ca principle of(7 more words not shown)
- Da particular example(4 more words not shown)
- Ebackground information providing(5 more words not shown)
Reading the argument
Why must a thinking machine be built like a brain? The brain's structure matters to the way a brain thinks, but perhaps another structure could produce thinking too. That makes me question Anders's recommendation to copy the structure closely.
Yang raises that distinction and brings in aircraft. According to the passage, workable planes differ structurally from birds, while machines closely modeled on birds haven't worked. That supports considering another route. I'm less convinced by Yang's next step: why does the aircraft example make a machine modeled on the brain likely to fail? A different route being possible doesn't establish that this route probably won't work.
Keep that question in mind, but now locate the statement's role. Yang first uses the aircraft comparison to support the prediction that brain-modeled machines are likely to fail. Yang then uses that prediction to support the recommendation to focus on function and ignore physical structure.
What we’re looking for
So the statement we're asked about does two jobs. It is a conclusion drawn from the analogy, and it becomes a reason for the final recommendation. We can identify both jobs without agreeing that the analogy establishes the prediction.
Working the answers
- A
The argument goes one step further than the targeted prediction. Its final conclusion recommends how researchers should proceed: focus on function and ignore the brain's physical structure. The likely-failure claim is offered as a reason for that recommendation, so it isn't the main conclusion.
- BCorrect
A subsidiary conclusion is a claim supported within the argument that then supports the main point. The aircraft example is supposed to make us believe that machines copying the brain will probably fail. That prediction is then supposed to make us accept Yang's recommended research approach.
The support runs into the targeted statement from the aircraft comparison, then out of it toward the recommendation. That is exactly the two-part role B describes.
- C
A principle of research would be a more general rule guiding how to investigate or design something. The targeted statement is a specific prediction about thinking machines modeled on brains. Yang argues for that prediction using the aircraft example; it isn't introduced as a research rule from which the argument begins.
- D
The aircraft case supplies the example. The statement about thinking machines is what Yang tries to establish from that example. D exchanges the example with the claim it is being used to support.
- E
This isn't merely context setting the scene. Yang gives a reason to believe the targeted claim, and the final recommendation depends on it. Those relationships make it an active step in the reasoning rather than background information.
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