Scientist: A controversy in paleontology centers on the question of wh

Question

Scientist: A controversy in paleontology centers on the question of whether prehistoric human ancestors began to develop sophisticated tools before or after they came to stand upright. I argue that they stood upright first, simply because advanced toolmaking requires free use of the hands, and standing upright makes this possible.

Which one of the following statements, if true, most weakens the scientist’s argument?

(A) Many animals that do not stand upright have learned to make basic tools.
(B) Advanced hunting weapons have been discovered among the artifacts belonging to prehistoric human ancestors who did not stand upright.
(C) Many prehistoric human ancestors who stood upright had no sophisticated tools.
(D) Those prehistoric human ancestors who first came to stand upright had no more dexterity with their hands than did those who did not stand upright.
(E) Many of the earliest sophisticated tools did not require their users to be able to stand upright.

Bunuel · Accepted Answer

EXPLANATION FROM Fox LSAT

The scientist says free use of the hands is necessary to make advanced tools, therefore prehistoric humans must have stood upright before they were able to make advanced tools. The problem with this argument is that “free use of the hands” and “standing upright” are not the exact same thing. Aren’t there other ways to get free use of the hands? What about sitting? What about hanging from your tail or your feet? What about lying on your back? All of these seem to be other ways that one might get free use of the hands, so this is my main problem with the scientist’s logic.

We’re asked to weaken the scientist’s logic, and I’m pretty happy with the attack we’ve already started above.

A) This is an attractive trap, but it’s conclusively wrong because it’s about  basic  tools whereas the argument was about  advanced  tools. For that reason, this answer is irrelevant.

B) “Advanced hunting weapons” sounds pretty damn close to “advanced toolmaking.” If there was a prehistoric human with advanced hunting weapons before standing upright, it seriously calls the scientist’s argument into question. This looks like a good weakener.

C) Just because some prehistoric humans stood upright before having advanced tools doesn’t mean that standing upright wasn’t a precursor to having advanced tools. In fact, it actually helps that idea. This is a strengthener, if anything, and we’re looking for a weakener.

D) Dexterity in the hands is only vaguely related to the argument in question here. And again, this answer could actually be used to suggest the idea that standing upright was first, then dexterity was gained, then advanced toolmaking came next. We’re looking for a weakener, and this could be read as a strengthener. Out.

E) My Roomba is an “advanced tool,” and it most definitely does not require me to stand upright while using it. Quite the opposite. But free use of the hands were required to make the Roomba in the first place. This doesn’t attack the conclusion of the argument, so it’s not a good weakener.

Our answer is B.

Nidzo · Answer

(A) Irrelevant as the scientist speaks of advanced tools, while this choice mentions basic tools.  Irrelevant

(B) This weakens the argument as it shows that there were sophisticated tools being used by human ancestors who did not walk upright.  Correct

(C) Does not weaken the argument.  Irrelevant

(D) Irrelevant. The argument does not center around dexterity, rather whether advanced toolmaking required free hands.  Irrelevant

(E) Does not speak of the making of the tools, rather their use which is irrelevant.  Irrelevant

Answer B

agrasan · Answer

Hi experts  GMATNinja   KarishmaB   MartyMurray   GMATNinja Two

(D) Those prehistoric human ancestors who first came to stand upright had no more dexterity with their hands than did those who did not stand upright.

Can you please help why option D is not correct?
My reasoning is if pre-historic humans who stood upright first don't have better hand skills than those pre-historic humans who didn't stand upright then it weakens my confidence in the author's conclusion that pre-historic humans stood first to make advanced tools.

Am I wrong in my thinking above because they might have stood upright first because of other reasons x, y, z, etc.? I mean "use of hands" can't be the only reason to stand upright first.

Could you please let me know where is the flaw in my original reasoning? 
Did I go in the right direction later after I knew D is incorrect?

GMATNinja · Answer

You'll want to pay close attention to the nuances of language in this one. Here's the conclusion again:

They don't need greater hand dexterity to use tools. They need to be able to USE their hands. It doesn't matter how skilled your hands are if you can't use them!

That's why (D) is wrong. It doesn't address the fact that these pre-historic humans would have free hands to hold tools once they stand.  This  is the core of the argument.

I hope that clears things up!

VerbalBot · Answer

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Scientist: A controversy in paleontology centers on the question of wh

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Scientist: A controversy in paleontology centers on the question of wh

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