In chapter 8 of the Sophistical Refutations, Aristotle claims that his theory of fallacy is complete in the sense that there cannot be more fallacies than the ones he lists. In this article I try to explain how Aristotle could have justified this completeness claim by analysing how he conceptualizes fallacies (dialectical mistakes which do not appear so) and what conceptual ingredients play a role in his discussion of fallacies. If we take the format of dialectical discussions into account, we (...) will see that there are only so many mistakes one can make which still do not appear to be mistakes. Aristotle’s actual list is almost identical to these apparent mistakes. (shrink)