Fallacies of Logical Structure:
Appeal to Ignorance (Argumentum ad Ignorantiam)

The fallacy of appeal to ignorance applies to the argument that a proposition is true because it hasn't been proven false. To put it differently, it is the argument that a proposition is true because the opposing proposition hasn't been proven true.

The fallacy has the structure:

Not-p has not been proven true. Therefore, p is true.

This is a fallacy because a lack of evidence for not-p does not imply that there is evidence for p. All it means is that we do not know that not-p is true.

I can't prove that a storm is not brewing in the atmosphere of Jupiter, but that would hardly count as evidence that a storm is brewing.


Begging the question | Equivocation |
Appeal to ignorance | Diversion

Fallacies of Logical Structure

© Copyright 1998, W.W. Norton & Co.