Logical Reasoning

PT114 · S4 · Q18 Anders: The physical structure of

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Anders: The physical structure of the brain plays an important role in thinking.

Main Conclusion (therefore)

Researchers would increase their chance of successfully developing a workable thinking machine if they focus on the brain's function and ignore its physical structure.

Intermediate Conclusion (So)

Thinking machines closely modeled on the brain are likely to fail.

Evidence / Intermediate Conclusion

The fact that the physical structure of the brain plays an "Important role" does not mean it plays "an essential role".

Evidence (after all)

No flying machine that's closely modeled on birds has worked. Meanwhile, workable aircraft does not share physical structure with birds.

Evaluate

We're being asked about Yang's 3rd claim, which is prefaced by So. The word "so" always means you are drawing a conclusion based (at least in part) on the previous claim, or that you are announcing the causal effect of the previous claim.

Here it's a reasoning conclusion (not a report on the causal effect: i.e. )

But we know that it's not the main conclusion, because the final sentence uses a Therefore. The word "therefore", just like "so", always means that you are deriving a conclusion based at least in part on the previous claim, or that you're saying the causal effect of the previous claim (much more rare).

Since this last claim is a prescriptive recommendation (that's redundant, yes), it's not the effect-half of some cause-effect pair. So we know this final claim is a conclusion that is built upon the 3rd sentence. And we know the 3rd sentence is a conclusion built upon the 2nd sentence.

The 1st sentence is supported (after all) by the 2nd sentence. The first two sentences team up to support the 3rd sentence, and the 3rd sentence supports the 4th sentence.

(2nd ⇢ 1st) → 3rd ⇢ 4th

Oh, the magic of keywords.

Goal

Let's look for an answer that reflects this hierarchy of who is supporting what. And we'll probably hear this claim described as an Intermediate Conclusion, which both provides support (for the 4th) and receives support (from the 2nd and 1st).

(2nd ⇢ 1st) → 3rd ⇢ 4th

18.

The statement "thinking machines closely modeled on the brain are also likely to fail" serves which one of the following roles in Yang's argument?

  1. the main conclusion of the

    Wrong Role

    The Main Conclusion is the final sentence.

    22% picked this

  2. Correct

    a subsidiary conclusion used in

    Why this is right

    We know it's a conclusion, because it's prefaced by "So". Does it help to support some other conclusion? Yes, it supports the final sentence, which uses the word "therefore" to indicate that its pulling its support from the 3rd sentence. Based on the fact that successful planes weren't modeled on the physical structure of birds (the ones that were failed), the author draws an intermediate conclusion that if we modeled thinking machines on the physical structure of the brain, they would probably also fail. Because thinking machines modeled on the brain's structure would probably fail, the author draws her final conclusion that we'd have better luck modeling these thinking machines on the function of the brain.

    Skill tested: Role · how this choice captures the argument's function is the move to repeat next time.

    73% picked this

  3. a principle of research invoked

    Not a Principle

    This is an opinionated prediction being drawn on the basis of premises about the success rate of aircraft made to look or not look like birds. It's not a "principle of research".

    1% picked this

  4. a particular example illustrating a

    Not General Conclusion / Not Example

    This is an opinionated prediction being drawn on the basis of premises about the success rate of aircraft that did / didn't resemble birds. It's not an example of anything. And the claim it supports (the final sentence) is not really a general claim. It's a specific recommendation regarding developing successful thinking machines.

    3% picked this

  5. background information providing a context

    Not Background

    We know this is a conclusion because it's prefaced by "So". This conclusion is an opinionated prediction being drawn on the basis of premises about whether aircraft that was / wasn't modeled on birds was successful.

    1% picked this

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