#1 - Mayor: There has been a long debate in city council

[Administrator]

Complete Question Explanation

Flaw in the Reasoning. The correct answer choice is (E)

Here, the mayor discusses city council’s options for dealing with the increased traffic congestion
projected for the future. According to the mayor, the council must choose between building a new
expressway (as the mayor would prefer), and doing nothing at all. By all accounts, doing nothing
would lead to gridlock within a decade, ruling out that option. Therefore, the mayor concludes, the
council should build the new expressway.

The argument can be broken down as follows:

• Premise: The council must either decide on the mayor’s plan or do nothing.
  
  Premise: Because of predicted gridlock within ten years, doing nothing is not an option.
  
  Conclusion: The council must therefore decide to adopt the mayor’s plan.

The problem with this argument is found in the first premise—with no justification, the mayor says
that the decision must be between his plan and...nothing. This type of flawed argument is known as
a “false dilemma.” Since the mayor provides no support for the assertion that his plan is the only
remaining viable option, this argument is flawed.

The stimulus is followed by a Flaw in the Reasoning question, so the correct answer choice will relay
the fact that the mayor, without justification, asserts that there are only two possible reactions to the
city council debate.

Answer choice (A): The issue here is not with the number of estimates considered; even the most
conservative estimates show that some solution is necessary within the next decade. That means that
a wider range of estimates would probably show an even greater need—but would not explain why
the only available action is the mayor’s expressway plan.

Answer choice (B): This choice might have caught people who were reading too quickly—the
mayor takes for granted that the two options presented are the only ones available, not that they are
mutually exclusive. Incidentally, this would not be a flaw, because the two choices presented are in
fact mutually exclusive: there is no way that the council can choose to do nothing and also choose to
do something.

Answer choice (C): The mayor is dealing with a situation that will no longer be viable within ten
years, so something must be done before then. The argument does not require considering the
possibility that traffic will eventually diminish, so this choice does not describe the flaw from the
mayor’s argument.

Answer choice (D): The problem needs to be resolved, because the city cannot deal with the traffic
gridlock; the mayor does not need to specify what the exact costs would be.

Answer choice (E): This is the correct answer choice. In an obvious effort to push the expressway
plan, the mayor claims that only two options are available—the expressway, or nothing—without any
support for the notion that only two options exist.

[blade21cn]

I take the first sentence "There has been a long debate in city council about how to accommodate projected increases in automobile traffic" as background information and not an element of the argument. Accordingly, the second sentence functions as a premise, as it's receiving no support from anywhere else in the stimulus, though it may appear like an intermediate conclusion: "Today, our choice is clear: either we adopt my plan to build a new expressway, or we do nothing." The credited response calls into question such a claim based upon false dilemma. So my question is: Is this question one of the rare occasions where an argument can be weakened by attacking the premise alone or doubted solely for the truthfulness of its premise? Thanks!

[Adam Tyson]

I'll say yes to that, blade21, but only sort of. The correct answer does indeed attack that premise, but it still also attacks the relationship between the premise and the conclusion. Imagine that the first premise was removed from the argument and you'll see that the argument is still an invalid false dilemma: "We cannot do nothing, so we must adopt my plan."