 Together the Sophistical Refutations and Locke’s Essay are the dual sources of our inheritance of fallacies. However, for four reasons they make for uneasy bedfellows. First, the ad fallacies seem to have a built-in dialectical character, which, it can be argued, Aristotle’s fallacies do not have (they are not sophistical refutations but are in sophistical refutations). Second, Aristotle’s fallacies are logical mistakes: they have no appropriate employment outside eristic argumentation whereas the ad-fallacies are instances of ad-arguments, often appropriately used in dialogues. Third, the appearance condition is part of the Aristotelian inheritance but it is not intimately connected with the ad-fallacies tradition. A fourth reason that contributes to the tension between the Aristotelian and Lockean traditions in fallacies is that the former grew out of philosophical problems, largely what are logical and metaphysical puzzles (consider the many examples in Sophistical Refutations), whereas the ad-fallacies are more geared to social and political topics of popular concern, the subject matter that most intrigues modern researchers on fallacy theory.