Anders: The physical structure of the brain plays an important role in thinking.
Main Conclusion (therefore)
Researchers would increase their chances of successfully developing a workable thinking machine if they focus on the brain's function and simply ignore its physical structure.
Intermediate Conclusion (So)
Thinking machines closely modeled on the brain's structure are likely to fail.
Intermediate Conclusion
The fact that the brain plays an important role in our thinking doesn't mean it plays an essential role.
Evidence (after all)
No flying machine based on the structure of birds has worked.
Evaluate
On Evaluate questions, we basically want to use the same mindset as on Weaken questions, so we can ask ourselves how we would fight this conclusion: how could ignoring the physical structure of the brain and focusing on the brain's function fail to help us successfully develop thinking machines?
Maybe there's something crucial we can learn from looking at the brain's structure, even if we decide not to copy that structure in the thinking machine we're building. Maybe we can't understand how the brain functions unless we pay attention to its physical structure.
Finally, maybe the analogy to birds / aircraft isn't strong support. Maybe there's some crucial difference when it comes to modeling aircraft after the structure of birds vs. modeling thinking after the structure of the brain, in which the former is a bad idea but the latter is a good one.
Goal
Look for an answer that gives us some idea we could use to object to Yang's argument, to either argue that the analogy between bird/aircraft and brain/thinking is a weak one, or to argue that researchers shouldn't ignore the physical structure of the brain, because there something important to gain from studying it.