Argument From Ignorance

Argument from ignorance, also known as argumentum ad ignorantiam or "appeal to ignorance" (where "ignorance" stands for: "lack of evidence to the contrary"), is a fallacy in informal logic. It asserts that a proposition is true because it has not yet been proven false, it is "generally accepted" (or vice versa). This represents a type of false dichotomy in that it excludes a third option, which is that there is insufficient investigation and therefore insufficient information to prove the proposition satisfactorily to be either true or false. Nor does it allow the admission that the choices may in fact not be two (true or false), but may be as many as four, (1) true, (2) false, (3) unknown between true or false, and (4) being unknowable (among the first three). In debates, appeals to ignorance are sometimes used to shift the burden of proof.

The fallaciousness of arguments from ignorance does not mean that one can never possess good reasons for thinking that something does not exist, an idea captured by philosopher Bertrand Russell's teapot, a hypothetical china teapot revolving about the sun between Earth and Mars; however this would fall more duly under the arena of pragmatism, wherein a position must be demonstrated or proven in order to be upheld, and therefore the burden of proof is on the argument's proponent. See also Occam's razor (assume simplicity over complexity).