#19 - Anders: The physical structure of the brain plays an important role in

[Administrator]

Complete Question Explanation

Evaluate the Argument. The correct answer choice is (A)

Yang’s argument is as follows:

          Premise: Important does not mean essential.

          Premise: No flying machine closely modeled on birds has worked; workable aircraft are
          structurally very different from birds.

          Premise/ So thinking machines closely modeled on the brain are also likely to fail.
          Subconclusion:
          Conclusion: In developing a workable thinking machine, researchers would therefore
          increase their chances of success if they focus on the brain’s function and
          simply ignore its physical structure.

Yang’s conclusion is very strong: “simply ignore the physical structure of the brain” when
developing a thinking machine. As you might expect, this extreme conclusion and the relatively
weak supporting evidence plays a role in the correct answer. Also note that the question stem uses
the word “whether” to turn each answer choice into a question.

Answer choice (A): This is the correct answer. The Variance Test proves the answer:

          If the answer is “Yes, they did provide crucial information” then developers should not ignore
          the physical structure of the brain because the reasoning used to make that judgment (via the
          flying machine analogy) is faulty.

          If the answer is “No, they did not provide crucial information” then the argument is
          strengthened because the analogy suggests it would be acceptable to ignore the physical
          structure of the brain.

Because the varied responses produce different evaluations of the argument, this answer is correct.

Answer choice (B): The conclusion is about ignoring the physical structure of the brain, and
information about what constitutes thinking will not help evaluate the argument. Apply the Variance
Test to disprove this answer by using opposite answers of “Yes” and “No.”

Answer choice (C): The relative amount of time spent on each project is not an issue in the stimulus.
Apply the Variance Test to disprove this answer, using opposite answers of “Yes, as much time was
spent” and “No, not as much time was spent.”

Answer choice (D): The argument does not involve the background of the researchers and the
projects they work on, only what they should focus on when trying to succeed. Hence, this answer
is incorrect. Apply the Variance Test, using opposite answers of “Yes, they are among those trying
to develop thinking machines” and “No, they are not among those trying to develop thinking
machines.”

Answer choice (E): The analogy in the argument is about flying machines that were modeled on
birds. The possibility that some flying machines that were not modeled on birds failed has no place
in the argument. Apply the Variance Test, using opposite answers of “Yes, some failed” and “No,
none failed.”

[lemonade42]

Hi Powerscore!

Just to confirm: (A) is correct because it's suggesting that if we figure out whether or not the physical structure of birds were used in the development process of the workable aircraft, we can use that to attack the analogy that Yang used which only looked at the end product of the workable aircraft. Thus, showing his error in reasoning was that looking at the end product doesn't necessarily show that modeling closely would fail and that he wrongfully concluded physical structure should be ignored.

My other question is for (E). I originally chose (E) because I thought that if we could show "Yes, they failed" then that means not closely modeling is bad so we shouldn't ignore physical structure (weakening Yang's conclusion). And if we could show "No, they did not fail" then that means not modeling based on physical structure is good so we should ignore physical structure (strengthening Yang's conclusion).

For (C), my thought process was that if "Yes, they take the same time", then that means no excess time was needed to build based on physical structure and if "No", then there is excess time needed to build based on physical structure". And those weaken and strengthen Yang's conclusion to ignore physical feature.
And similarly to (D), "Yes" and "No" answers would mean that researchers thinking structure is important or not (because they specialize in it) would impact the validity of Yang's conclusion to ignore physical structure when building the workable thinking machine.

Can you help point out the flaws in my thinking?
Thank you!

[Chandler H]

Hi Powerscore!

Just to confirm: (A) is correct because it's suggesting that if we figure out whether or not the physical structure of birds were used in the development process of the workable aircraft, we can use that to attack the analogy that Yang used which only looked at the end product of the workable aircraft. Thus, showing his error in reasoning was that looking at the end product doesn't necessarily show that modeling closely would fail and that he wrongfully concluded physical structure should be ignored.

My other question is for (E). I originally chose (E) because I thought that if we could show "Yes, they failed" then that means not closely modeling is bad so we shouldn't ignore physical structure (weakening Yang's conclusion). And if we could show "No, they did not fail" then that means not modeling based on physical structure is good so we should ignore physical structure (strengthening Yang's conclusion).

For (C), my thought process was that if "Yes, they take the same time", then that means no excess time was needed to build based on physical structure and if "No", then there is excess time needed to build based on physical structure". And those weaken and strengthen Yang's conclusion to ignore physical feature.
And similarly to (D), "Yes" and "No" answers would mean that researchers thinking structure is important or not (because they specialize in it) would impact the validity of Yang's conclusion to ignore physical structure when building the workable thinking machine.

Can you help point out the flaws in my thinking?
Thank you!

Hi Lemonade42,

Yes, your explanation of answer choice (A) is right on! You must, however, keep in mind that the question is asking which is most helpful. (A) is very consequential because if studies of the physical structure of birds DID provide crucial information, then Yang's argument (increase chances of success if ignore physical structure) is pretty much destroyed.

As for answer choice (E)—you're right to say that it does weaken Yang's argument very, very slightly. However, it is more irrelevant than anything else. If these other flying machines did fail to work, that doesn't prove anything about whether or not modeling on birds was good. If they didn't fail to work, then that just proves what we already know: working airplanes aren't modeled on birds.

As for (C) and (D), they are also pretty much irrelevant. Yang's answer doesn't talk at all about how much time it should take to develop a workable thinking machine, so (C) does not really help us evaluate the argument. (D) is also irrelevant—just because researchers who study structure of the brain are "among those" working on the problem doesn't mean that it's consequential for Yang's argument.

[TonyJo]

Hello, PowerScore!

I was able to select the correct answer, but I had a question with respect to the explanation for answer choice (E). The explanation would seem to suggest that when using the Variance Test, the polar opposite of "some failed" would be "none failed. " While I am aware that "none" is the logical opposite of "some," I had come across another PowerScore discussion forum where it is explained that "some doesn't really have a polar opposite because it doesn't sit at the extreme end of a continuum." I tend to agree with that statement, but I am confused as to whether the Variance Test would require you to use a logical opposite when a polar opposite is not available (as the explanation for answer choice (E) seems to suggest).

Thank you very much for your help!

[Jeff Wren]

Hi Tony,

You're right that the polar opposite of "none" would be "all" rather than "some," so "some" and "none" are logical opposites rather than polar opposites. In this case though, the best way to use the Variance test would be to use the logical opposites.

If Answer E were the correct answer, then knowing whether "some" failed versus "none" failed would be the key piece of missing information that we'd want to know to evaluate the argument. Here, of course, it is not.

What you definitely wouldn't want to use as the opposite of "some have failed" would be "some have succeeded" because these are not opposites at all and are completely consistent with each other. This type of middle of the road test would not necessarily produce definitive results either way and would not help to test the answer.