Issuepedia:Arguing/challenge/undefended


 * Rule: If a challenged assertion remains undefended, then it is assumed to be false.

Justification
The only alternatives would be:
 * Assume that the assertion is true.
 * Assume that the assertion might be true.

Either of these alternatives would give honest participants an unfair disadvantage, since false assertions are inexpensive to invent and often expensive to refute.