Burden of Proof in a Modified Hamblin Dialogue System
Douglas Walton · 2011
Abstract: In his book on fallacies, Hamblin built a very simple system for argumentation in dialogue he called the Why-Because System with Questions. In his discussion of this system, he replaced the concept of burden of proof with a simpler concept of initiative, which could be described as something like getting the upper hand as the argumentation moves back and forth in the dialogue between the one party and the other. No doubt he realized that the con-cept of burden of proof was too complex a matter to be dealt with in the limited scope of his chapter on formal dialogue systems. In this pa-per is shown how an extended ver-sion of Hamblin’s dialogue system provides a nice way of modeling the phenomenon of shifting of burden of proof in a dialogue, yielding a pre-cise way of distinguishing between different kinds of burden of proof, and dealing with fallacies like the argumentum ad ignorantiam (argu-ment from negative evidence).