Professor: Many scientists hypothesize that there is an invisible

Question

Professor: Many scientists hypothesize that there is an invisible "light-absorbing medium" in outer space. In support, they argue that the medium's existence would explain the low visibility of other star systems from Earth. But there is actually no reason to believe that the hypothesis is correct, since the low visibility in question is already completely explained by the general theory of relativity.

Which one of the following is an assumption required by the professor's argument?

(A) The low visibility of other star systems from Earth would not be adequately explained by the existence of an invisible light-absorbing medium in outer space, even if there were such a medium.

(B) The hypothesis of an invisible light-absorbing medium in outer space is correct only if it adequately explains the low visibility of other star systems from Earth.

(C) A hypothesis is likely to be correct if there is some phenomenon that it adequately accounts for and that is not adequately accounted for by an existing theory.

(D) Most scientists who posit the invisible light-absorbing medium accept the general theory of relativity.

(E) The general theory of relativity does not depend upon the hypothesis that there exists an invisible light-absorbing medium in outer space.

SafeRay · Answer

Professor's claim: no reason to believe the light-absorbing medium, because low visibility is already fully explained by relativity.

Key gap: using relativity as a competing explanation only works if relativity does not itself depend on that medium.

Negation check on E:
If relativity DID depend on the medium, then "relativity explains it" would not undermine the medium. Argument collapses.
So E is required.

Quick kills:
A: professor never needs "medium can't explain it"
B: about when the hypothesis is correct, not the professor's leap
C: closer to the scientists' reasoning, not the professor's
D: what scientists believe is irrelevant

Answer: E

guddo · Answer

Professor: Many scientists hypothesize that there is an invisible "light-absorbing medium" in outer space. In support, they argue that the medium's existence would explain the low visibility of other star systems from Earth. But there is actually no reason to believe that the hypothesis is correct, since the low visibility in question is already completely explained by the general theory of relativity.
 
 Which one of the following is an assumption required by the professor's argument?

The professor says the light-absorbing medium is unnecessary because the low visibility of other star systems is already fully explained by general relativity.  The key assumption  is that the relativity explanation does not itself rely on the existence of that  light-absorbing medium .

(A) The low visibility of other star systems from Earth would not be adequately explained by the existence of an invisible light-absorbing medium in outer space, even if there were such a medium.

This is not required. The professor does not need to deny that the medium could explain the low visibility. The point is that another explanation already fully explains it.

(B) The hypothesis of an invisible light-absorbing medium in outer space is correct only if it adequately explains the low visibility of other star systems from Earth.

This is not required. The professor is attacking the support offered for the hypothesis, not saying the hypothesis could be correct only for that one reason.

(C) A hypothesis is likely to be correct if there is some phenomenon that it adequately accounts for and that is not adequately accounted for by an existing theory.

This is not required. This gives a general rule about when a hypothesis may be likely correct, but the professor’s argument depends on the opposite situation: the phenomenon is already explained by an existing theory.

(D) Most scientists who posit the invisible light-absorbing medium accept the general theory of relativity.

This is irrelevant. The scientists’ acceptance of relativity does not determine whether the medium is needed to explain the low visibility.

(E) The general theory of relativity does not depend upon the hypothesis that there exists an invisible light-absorbing medium in outer space.

This is correct. If general relativity’s explanation depended on the existence of the light-absorbing medium, then the relativity explanation would not remove support for the medium. So the professor must assume that relativity explains the low visibility independently of that hypothesis.

Answer: (E)

vasu1104 · Answer

conclusion= there is no reason to believe that the hypothesis is correct.

reason= since low visibility in question is already completely explained by general theory of relativity.

many scientists believed hypothesize that there is an invisible light absorbing medium in outer space.
they argue that medium's existence would explain the low visibility of other star systems from earth.

here the low visibility (X) was explained by general theory (Y)
so no reason to believe that hypothesis (invisible light absorbing medium- Z) is correct

because Y explained X, Z is incorrect. but what if Y is dependent on Z.
so they must be assuming that Y is not dependent on Z.

A if there is no way to explain it adequately even with medium then whats the point of making hypothesis and then making conclusion. this is so wrong, out.
B but thats what passage is trying to tell. so this doesnt bring anything new to table, out.
C this talks about conditional situation in which hypothesis could be correct. so out.
D this is out of context and has no impact at all. out.
E perfect. it says that Y is not dependent on Z at all. but when you negate this, it means Y is indeed dependent on Z. in that case conclusion breaks down. so keep.

choice E

Professor: Many scientists hypothesize that there is an invisible

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards

GMAT Critical Reasoning (CR) Questions

Professor: Many scientists hypothesize that there is an invisible

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards