PrepTest 157, Section 3, Question 23
Superstring theory is a controversial new theory in(65 more words not shown)
Which one of the following(8 more words not shown)
- ASuperstring theory would(22 more words not shown)
- BPhysical theories that(16 more words not shown)
- CSome physical theory(26 more words not shown)
- DA physical theory(19 more words not shown)
- EA theory that(20 more words not shown)
Reading the argument
Offering an explanation doesn't establish that it's right. Someone could say gravity exists because of fairies; that would be a proposed story, not evidence for it.
So superstring theory's promise to explain gravity raises two questions here. Can we test it? And how much does it actually explain? The passage describes an enormous obstacle to testing: a particle accelerator 100 trillion kilometers long. It also says the theory hasn't adequately explained why gravity has the strength it does.
What we’re looking for
Neither point proves the theory false. Difficulty checking an idea concerns our ability to establish whether it's right. Leaving part of a phenomenon unexplained concerns how complete the explanation is. For the question about what is most strongly supported, keep those limits in view: there are problems with testing and explanatory completeness, but no demonstrated disproof.
Working the answers
- A
The passage says the theory hasn't succeeded in adequately explaining gravity's strength. That doesn't tell us the theorists haven't attempted it. They may already have tried extensively. And attempting an explanation doesn't guarantee a better result. This proposed improvement isn't established by identifying the problem.
- B
Being more established doesn't automatically mean a theory explains every physical phenomenon better. The passage mentions established theories to contrast their aims with superstring theory's proposed explanation of gravity. It doesn't rank their overall explanatory quality. B reaches well beyond the information supplied.
- C
A failure by superstring theory doesn't establish a success by some other theory. Maybe a more established theory can explain gravity's precise strength, or maybe none can. We weren't told. The mention of other theories isn't evidence that one of them has solved this problem.
- D
Whether a theory is true is different from whether we can practically test it. An enormous testing requirement might prevent us from checking a correct explanation. The passage calls that requirement a problem; it doesn't say reality must conform only to theories we can conveniently test.
- ECorrect
The final sentence explicitly treats failure to account for gravity's strength as a problem for a theory claiming to explain gravity's nature. “Deficient” captures that shortcoming. If the explanation leaves the force's actual strength unexplained, it has missed part of what an adequate account should address. That doesn't require declaring the whole theory false.
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