Image via WikipediaArgument from ignorance - encyclopedia article about Argument from ignorance.:
"Argument from ignorance, also known as argumentum ad ignorantiam or appeal to ignorance, is an informal logical fallacy. It asserts that a proposition is necessarily true because it has not been proven false (or vice versa). This represents a type of false dichotomy in that it excludes a third option: there is insufficient data and the proposition has not yet been proven to be either true or false. In debates, appeals to ignorance are sometimes used to shift the burden of proof."