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Zorluk: ZorWeakening Arguments

A regional agricultural authority plans to subsidize the replacement of traditional flood irrigation with subsurface drip irrigation across farms in a drought-prone river basin. Because subsurface drip irrigation reduces per-acre water loss to evaporation by 35 percent, the authority concludes that implementing this technology region-wide will substantially increase the total volume of water remaining in the basin's underground aquifer each year. Which of the following, if true, most seriously weakens the agricultural authority's argument?

  1. A
    Subsurface drip irrigation systems require specialized filtration equipment that significantly increases annual energy consumption for participating farms.
  2. A substantial portion of the unevaporated water applied during traditional flood irrigation percolates down through the soil and recharges the aquifer, whereas drip irrigation delivers water directly to roots with virtually no deep soil percolation.Cevap
  3. C
    Subsurface drip systems have been successfully adopted by commercial farms in adjacent agricultural districts that share similar soil compositions.
  4. D
    Projected changes in international trade policy over the next decade may prompt regional farmers to shift production toward crops that require more total water.
  5. E
    Farms utilizing subsurface drip irrigation report an average 15 percent increase in crop yields compared to farms using traditional flood irrigation.

Cevap

The argument is most seriously weakened by the statement that unevaporated flood irrigation water previously percolated down to recharge the aquifer, whereas drip irrigation eliminates this percolation.
The correct answer weakens the argument by demonstrating that traditional flood irrigation served a vital function in replenishing the aquifer through deep soil percolation. By replacing flood irrigation with drip irrigation—which supplies only enough water for plant absorption—the basin loses its primary mechanism for aquifer recharge. Thus, even though evaporation is reduced, the net input of water into the underground aquifer decreases, directly undermining the authority's conclusion.

Adım Adım Çözüm

1
Deconstruct the argument core
Premise: Subsurface drip irrigation reduces per-acre water loss from evaporation by 35%. Conclusion: Region-wide adoption will substantially increase the total volume of water remaining in the underground aquifer.
Identifying the explicit premise and conclusion isolates the author's underlying assumption.
2
Identify the unstated assumption
The argument assumes that water lost to evaporation is the only factor determining how much water reaches or stays in the aquifer, and that water not lost to evaporation was not already returning to the aquifer under flood irrigation.
Weakening questions require finding new information that shatters the link between the premise and conclusion.
3
Evaluate the impact of the correct answer choice
If unevaporated water under flood irrigation regularly seeped down to recharge the aquifer, then flood irrigation was actually replenishing the underground water storage. Drip irrigation eliminates this recharge mechanism, meaning less total water reaches the aquifer despite reduced evaporation.
This directly refutes the conclusion that aquifer levels will increase.

Anahtar Kavram

Weakening Causal and Plan-to-Goal Arguments via Countervailing Factors
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Konular

Weakening Arguments

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