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Zorluk: OrtaRuling Out Alternate Explanations (Defender)

Maritime Analyst: Three years ago, several major shipping companies voluntarily installed novel hull-lubrication systems on a portion of their cargo fleets. A recent analysis shows that over the past two years, the vessels equipped with these systems consumed, on average, 12 percent less fuel per voyage than comparable vessels in the same fleets that were not equipped with the systems. This clearly demonstrates that the hull-lubrication systems are highly effective at reducing fuel consumption.

Which one of the following is an assumption required by the maritime analyst's argument?

  1. A
    The hull-lubrication systems are the only technological modifications capable of producing at least a 12 percent reduction in a cargo vessel's fuel consumption.
  2. The vessels equipped with the hull-lubrication systems were not operated at significantly lower average speeds than the unequipped vessels during the two-year period.Cevap
  3. C
    The total volume of fuel consumed by the equipped vessels over the two-year period was exactly 12 percent less than the total volume of fuel consumed by the unequipped vessels.
  4. D
    The financial savings resulting from the reduction in fuel consumption exceeded the initial cost of installing the hull-lubrication systems.
  5. E
    The recent analysis included data from every shipping company that has ever installed a novel hull-lubrication system on its vessels.

Cevap

The assumption that the equipped vessels were not operated at significantly lower average speeds than the unequipped vessels.
The argument concludes that hull-lubrication systems cause a reduction in fuel consumption based on the observation that vessels with the systems used less fuel. However, this relies on the assumption that no other factor—such as sailing speed—caused the reduction. If the equipped vessels were driven much slower, the speed reduction would explain the fuel savings, entirely undermining the analyst's conclusion. Therefore, the argument must assume that this alternative cause is not present.

Adım Adım Çözüm

1
Identify the conclusion of the argument.
The conclusion is that the novel hull-lubrication systems are highly effective at reducing fuel consumption.
This is the analyst's main claim, signaled by the phrase 'This clearly demonstrates that...'
2
Identify the primary evidence (premise) supporting the conclusion.
The evidence is a correlation: vessels equipped with the systems consumed an average of 12 percent less fuel per voyage than comparable unequipped vessels.
The analyst uses this observed data to establish a causal relationship between the systems and the fuel savings.
3
Evaluate the logical gap between the evidence and the conclusion.
The argument assumes that the hull-lubrication system is the actual cause of the fuel savings, failing to consider other potential differences in how the two groups of vessels were operated.
In causal arguments based on observation, there is always a risk that a third variable or alternate cause is responsible for the effect.
4
Apply the Negation Technique to the correct answer choice.
If we negate the correct choice (assuming they WERE operated at significantly lower speeds), the lower speeds would provide an alternative explanation for the fuel savings, destroying the conclusion that the systems were responsible.
A necessary assumption is one that, if proven false, causes the argument to collapse. Ruling out an alternate explanation is a classic 'defender' assumption.

Anahtar Kavram

Necessary Assumption - Defender (Ruling out alternate explanations for an observed effect)
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Konular

Ruling Out Alternate Explanations (Defender)

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