Questions: Understanding and Evaluating Burden of Proof

Question 1

Someone says, 'I believe there is life on other planets. Prove me wrong.' What is wrong with this rhetorical move?

Model answer: This is an illegitimate burden-shift. The person making the positive claim (life on other planets exists) bears the burden of providing supporting evidence. Demanding that others disprove the claim before it can be rejected inverts the proper epistemic relationship: the claimant must first establish a prima facie case before the respondent is obligated to rebut it. Until evidence is offered, simple non-acceptance is a rational default.

This is sometimes called 'shifting the burden' or invoking 'Russell's teapot' territory. Bertrand Russell illustrated this with the claim that a teapot orbits the sun between Earth and Mars — the fact that no one can disprove it does not oblige us to accept it. The burden lies with whoever makes the positive existential assertion.

Question 2

Extraordinary claims require stronger evidence than ordinary claims before rational acceptance.

• T. True
• F. False

Answer: True

This is the asymmetry principle in burden-of-proof reasoning. An ordinary claim ('I had coffee this morning') aligns with routine background knowledge and requires minimal support. An extraordinary claim ('I communicated with the dead') conflicts with well-established background knowledge, so the evidence required before rational agents should update significantly is correspondingly high. The threshold shifts with how far the claim departs from what we already have reason to believe.