LSAT (Law School Admission Test)Logical ReasoningHard

Biologist: The recent increase in the population of deer in suburban areas is primarily due to increased deforestation, which forces deer into human-dominated habitats. However, a local wildlife expert points out that the deer population has also increased in areas where deforestation rates have remained stable. Therefore, the biologist's claim is incorrect.

  1. AIt ignores the possibility that the local wildlife expert is biased.
  2. BIt does not provide data on the absolute numbers of deer in the affected areas.
  3. CIt assumes that stable deforestation rates imply a stable availability of natural habitats for deer.
  4. DIt fails to consider that deforestation might be a contributing factor even if not the sole cause.
Show answer & explanation

Correct answer: D. It fails to consider that deforestation might be a contributing factor even if not the sole cause.

The biologist claims deforestation is the *primary* cause. The wildlife expert's counter-argument shows that deer populations increased even without increased deforestation, suggesting deforestation isn't the *sole* cause. However, a factor being the 'primary' cause does not mean it is the *only* cause. Other factors can exist, and deforestation could still be the most significant one overall. The counter-argument only shows it's not the *exclusive* cause, which doesn't fully refute the 'primary' claim.

Why the other options are wrong

  • A. Attacking the source (wildlife expert) is an ad hominem and not a flaw in the reasoning of the expert's *statement* as presented in the argument.
  • B. Absolute numbers would be useful, but the logical flaw lies in the interpretation of the *relative* change and its impact on the 'primary cause' claim.
  • C. The argument's flaw isn't in what 'stable deforestation' implies, but in the jump from that to refuting the 'primary cause' claim.

Overstated Refutation (Failing to Distinguish 'Primary' from 'Sole')

A flaw in reasoning where an argument attempts to refute a claim about a 'primary' or 'major' cause by presenting evidence that merely shows it is not the 'sole' or 'exclusive' cause.

  • Confuses 'most important' with 'only'.
  • Evidence against exclusivity does not negate primacy.
  • Requires careful attention to the degree of causation claimed.

Memory trick: Primary is not sole; don't let one part control the whole!

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