PrepTest 107, Section 3, Question 11
Astronomer: Astronomical observatories in many areas have become(67 more words not shown)
The astronomer's argument proceeds(1 more words not shown)
- Aappealing to a(8 more words not shown)
- Bquestioning the accuracy(9 more words not shown)
- Cproposing an alternative(6 more words not shown)
- Dmaking a distinction(2 more words not shown)
- Eoffering a counterexample(4 more words not shown)
Reading the argument
Do well-lighted streets have to mean a sky in which we can't see the stars? The people described here think so: streetlights are necessary for safety, and the interference is supposedly unavoidable.
The astronomer responds with Sandsville. The city limits unnecessary lighting and directs its streetlights downward, while the observatory retains a relatively clear view. That is meant to show a way to keep lighting on the streets without sending so much of it into the sky.
I would still want to know whether those special lamps actually light the streets well. Dark skies alone wouldn't establish both parts of the conclusion. And I might wonder whether the arrangement would work in a much larger city. But the conclusion only says the combination is possible, not that the same design will succeed everywhere. A successful example in one city could establish that limited claim.
What we’re looking for
We're asked to describe the method. The astronomer offers Sandsville as an example against the general claim that serious interference is inevitable. We can recognize what the example is intended to show even while asking whether the evidence fully establishes its success.
Working the answers
- A
The speaker is an astronomer, but the reasoning doesn't ask us to accept a claim because a scientific authority says so. The support is the reported situation in Sandsville. Identifying the speaker's occupation is different from citing expertise as the reason to believe the conclusion.
- B
The astronomer does not dispute the reports of observatories harmed by city lights or deny the need for safe streets. The response says that Sandsville avoids the supposed unavoidable tradeoff. It challenges what is claimed to be inevitable by presenting a different case, rather than showing the opposing side's evidence is inaccurate.
- C
We aren't offered a different explanation of a natural phenomenon. The astronomer doesn't propose some new cause of the obscured stars. The argument concerns whether cities can manage their artificial lighting so that the interference is reduced.
- D
The argument does not distinguish two definitions or clarify how one term differs from another. It contrasts a general prediction about street lighting with a city offered as an exception. The presence of different kinds of lighting does not turn the argument into a discussion of word meanings.
- ECorrect
The general claim is that the need for streetlights makes interference with observing the stars inevitable. Sandsville is the proposed counterexample: it is presented as keeping its streets lighted and its observatory's view relatively clear.
That example is supposed to defeat the claim of inevitability. It need not show that every city has solved the problem or that Sandsville has eliminated every bit of stray light. The conclusion allows relatively dark skies.
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