Abstract

SummaryThis paper outlines a three‐part analysis of the traditional informal fallacy of ad ignorantiam. As initially characterized, the fallacy consists in arguing that failure to prove falsity implies the truth of a proposition.First, the fallacy is located within confirmation theory as a confusion between the categories of “lack of confirming evidence” and “presence of disconfirming evidence”. Second, the structure of the fallacy can be seen as an illicit negation shift in Hintikka‐style epistemic logic. Third, the fallacy can be studied as an attempt to unfairly shift the burden of proof in a dialectical game. We suggest that research on ad ignorantiam needs a broadening of the scope of philosophical logic to encompass concepts of correct argument in these three contexts