PrepTest 153, Section 3, Question 3
Columnist: Although it is our civic duty to(40 more words not shown)
The conclusion of the columnist's(13 more words not shown)
- APublic health would(8 more words not shown)
- BProponents of expensive(11 more words not shown)
- CScientific evidence exists(12 more words not shown)
- DNo investigation of(13 more words not shown)
- ERerouting high-tension power(19 more words not shown)
Reading the argument
We have a duty to protect public health, but we shouldn't move these power lines away from crowded areas? I want to know why. Are the lines dangerous in the first place? If they are, what reason would justify leaving them where they are?
My first thought is a tradeoff. If a change left people without reliable electricity, that could create problems of its own. Perhaps the benefit of keeping the power supply would outweigh a suspected health risk from the lines. That could be an argument someone makes. But rerouting a line doesn't necessarily mean losing electricity, and we haven't been given either the risk or that tradeoff.
Then the columnist gives a different reason: limited resources should protect people only against well-substantiated threats. In plain terms, there needs to be solid support for the claim that something is dangerous before we spend these resources on protection from it.
What we’re looking for
All right—what do we know about the evidence against these power lines? Nothing yet. If their danger were well established, the columnist's rule wouldn't explain why we should leave them alone. To make this conclusion follow, we need to put the lines outside the category the rule allows us to spend on: their threat has not been established. That is the missing fact I'd look for, rather than the electricity-versus-health tradeoff I initially imagined.
Working the answers
- A
Losing electricity could harm public health, but the proposed change is rerouting power lines, not eliminating electric power. We have no reason to assume that one causes the other. And this doesn't complete the columnist's stated reasoning about which threats have enough evidence behind them. It resembles our initial guess about a different argument.
- B
Calling proponents unrealistic doesn't tell us whether the health threat is well substantiated. They could misunderstand some economic issue and still be right that the lines are dangerous. We need the status of this particular threat under the columnist's rule, not a general criticism of the people recommending precautions.
- C
Evidence of dangers from various modern practices could be relevant to deciding which problems deserve resources. But which practices? This doesn't tell us whether high-tension power lines are among the established threats. That is the particular case the conclusion concerns.
- DCorrect
No investigation has established a health threat from these lines. Now the pieces connect: the columnist permits spending protective resources only on well-substantiated threats, and this supposed threat has not been substantiated. Under that rule, rerouting the lines to address the suspected danger is not an allowed use of those resources.
This does not prove the lines harmless. Failing to establish a danger and establishing that there is no danger are different results. The argument uses the former as its reason not to act.
- E
Making future study harder gives us a different consideration about rerouting. It doesn't show whether a threat has already been established, and it doesn't tell us that preserving opportunities for study should take priority. The columnist's actual rule concerns the evidence for a health threat.
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