 Systems of informal logic that adopt a fallacy approach can be summarized as instances of I in which I = {B, L, A, S, T}, where: B = Fallacy Theory, and T = a set of fallacies used to judge instances of argument. An even narrower set of (“Hamblin”) systems can be defined as systems in which B = Hamblin. This is a family of systems which is rooted in the account of fallacies proposed in Hamblin 1970. 