LSAT (Law School Admission Test)Logical ReasoningHard

Philosopher: 'Since it is impossible to definitively prove the existence of extraterrestrial life, it is therefore impossible to definitively claim that extraterrestrial life does not exist.'

  1. AThe philosopher assumes that the burden of proof for non-existence is the same as for existence.
  2. BThe existence of extraterrestrial life is a matter of scientific inquiry, not philosophical debate.
  3. CIt is not impossible to definitively prove the existence of extraterrestrial life; we just haven't yet.
  4. DThe absence of evidence is not necessarily evidence of absence.
Show answer & explanation

Correct answer: A. The philosopher assumes that the burden of proof for non-existence is the same as for existence.

The philosopher argues that because you can't prove X, you also can't prove not-X. This relies on the unspoken assumption that the same standards or burdens of proof apply equally to proving existence and proving non-existence. However, proving non-existence often requires an exhaustive search, which is a different kind of burden than proving existence, which might only require one instance. Option B directly points out this underlying assumption.

Why the other options are wrong

  • B. This dismisses the context but doesn't analyze the logical structure of the argument presented.
  • C. This challenges a premise, but the flaw is in the *reasoning* from the premise, not the premise itself.
  • D. While true, this statement is more a general principle related to the topic than an identification of the specific flaw in the philosopher's reasoning, which hinges on the *burden* of proof.

Assumption of Equal Burden of Proof

A logical fallacy where an argument assumes that the difficulty or requirements for proving a negative claim are equivalent to proving a positive claim.

  • Often related to arguments from ignorance.
  • It's generally harder to prove a negative (absence) than a positive (presence).
  • The burden of proof typically lies with the one making the positive claim.

Memory trick: Don't just listen to words, hear the silent chords!

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