Appeal to Ignorance
The claim that a statement is true because it has not been proven false, or that a statement is false because it has not been proven to be true. Famously refuted by Carl Sagan with the statement, "Absence of Evidence is not evidence of absence." Based on shifting the burden of proof onto whichever side of the argument you want to lose. If something can not be proven either way, just act like the opinion opposite of yours is inherently sillier, and you can assert that your position must be assumed correct until someone from the other side can prove you wrong. Usually involves an appeal to one's own authority and/or Burden of Proof Fallacy, and is essentially a claim of personal omnipotence; if the arguer cannot imagine a way for something to have happened, it is clearly impossible.
- Argument from Ignorance
- Argument from Lack of Imagination
- Argument from Personal Incredulity
- The popular argument "you cannot prove X does not exist, so it does" (or vice-versa) is the typical case. X can be God, aliens, a huge government conspiracy, unicorns, whatever. It's more common with arguments that are harder to prove, one way or the other.
Live Action Television
- The 'Devil's Proof' is a favorite of the witches in Umineko no Naku Koro ni.
- Every fan argument on a message board about anything that had a poster defending their pet Fanon with "Well, you can't prove that it didn't happen that way offstage!" or "For all we know..."