 Siegel and Biro (1992, 1995) hold an epistemic account of fallacies, contrasting their view with dialectical/rhetorical approaches, because matters extraneous to arguments, such as being a practice that leads to false beliefs or not being persuasive, are not in their view a sufficient condition to make an argument a fallacy. They take the position that “it is a conceptual truth about arguments that their central … purpose is to provide a bridge from known truths or justified beliefs to as yet unknown … truths or as yet unjustified beliefs” (1992, 92). Only arguments that are “epistemically serious” can accomplish this; that is, only arguments that satisfy the extra-formal requirement that premises are knowable independently of their conclusions, and are more acceptable epistemically than their conclusions, can fulfill this function. A purely logical approach to argument will not capture this requirement because arguments of the same valid form, but with different contents, may or may not be epistemically serious, depending on whether the premises are epistemically acceptable relative to the conclusion.