Fallacy A topic of fallacies that exists at the intersection of rhetoric with other disciplines, here logic. It might be argued that the notion of fallacy plays a foundational role in logic, or at least in informal logic. Here one notices a disparity, to illustrate which one need only observe that while most rhetoricians would seem to agree that there are topoi, yet many logicians and others argue whether there are fallacies, and whether they are always fallacious. In other words, foundational disputes about the very topic of fallacy-how it is to be understood and whether there are any-characterize inquiry to this day.