Question

Difficulty: MediumConfusing Necessary and Sufficient Conditions

To qualify for the Municipal Green Architecture Grant, a building renovation project must reduce its annual energy consumption by at least 40 percent. The recent renovation of the historic Sterling Theater successfully reduced its annual energy consumption by 45 percent. Therefore, the Sterling Theater project will definitely receive the Municipal Green Architecture Grant.

Which of the following best describes the flaw in the reasoning above?

  1. A
    It assumes that receiving the municipal grant is what caused the Sterling Theater to achieve its energy reduction.
  2. B
    It bases a broad judgment about all municipal building projects on the outcome of a single theater renovation.
  3. It treats a requirement necessary for obtaining the grant as if it were a sufficient condition to guarantee receiving the grant.Answer
  4. D
    It assumes without evidence that other historic theaters in the city are unable to meet the energy reduction threshold.
  5. E
    It infers that achieving a 45 percent energy reduction will negatively impact the overall operating budget of the theater.

Answer

The argument's flaw is that it treats a necessary prerequisite (reducing energy consumption by at least 40 percent) as though it were a sufficient condition that guarantees receiving the grant.
The passage establishes that achieving a 40 percent energy reduction is a necessary condition ('must') to qualify for the grant. The author observes that the Sterling Theater achieved a 45 percent reduction and concludes that it will definitely receive the grant. This reasoning is flawed because satisfying a necessary condition makes a project eligible, but does not guarantee that the grant will be awarded; there may be other criteria, budget limitations, or competitive evaluations involved. Thus, the argument incorrectly treats a necessary condition as a sufficient one.

Step-by-Step Solution

1
Analyze the premises and conditional statement
The text states that reducing energy consumption by at least 40 percent is a mandatory requirement ('must') to qualify for the grant. This establishes energy reduction as a necessary condition.
Identifying indicator words like 'must' helps distinguish necessary conditions from sufficient conditions.
2
Analyze the evidence and conclusion
The Sterling Theater achieved a 45 percent reduction (satisfying the necessary condition), and the author concludes that the project will 'definitely receive' the grant.
The author concludes that satisfying the entry requirement guarantees the final outcome.
3
Identify the logical vulnerability
Satisfying a necessary requirement makes an applicant eligible to be considered, but does not guarantee selection (there could be limited funds, additional criteria, or competing applicants).
Mistaking eligibility (necessary) for a guarantee of success (sufficient) is a classic formal logic flaw.

Key Concept

Confusing Necessary and Sufficient Conditions
Estimated Time:1m 30s
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