The Greeks invented the philosophical discipline known as ‘logic’, whose core is the study and classification of valid forms of inference. Since its inception Greek logical inquiry was motivated by the need to establish the standards of correctness for philosophical reasoning and argument. Throughout antiquity this inquiry also focused on the identification, diagnosis, and classification of forms of argument that are invalid, unsound, or otherwise problematic. Within these, special attention was devoted to those forms of argument that, despite their deficiency, somehow appear to be valid, and thus can easily induce us in error, or can be exploited ‘sophistically’ to mislead others. To be able to defend oneself, by detecting the fallacies in someone else’s reasoning, was a valuable skill in a context in which philosophical discourse developed in a dialectical setting, and one’s opponents could use, whether consciously or inadvertently, fallacious arguments to (apparently) refute one’s side of the argument and to win the debate. In addition, the study of fallacies was deemed important to avoid errors in one’s own reasoning, which was construed by Plato as a sort of inner, silent dialogue which one entertains with oneself.1