Opportunistic Processing in Arguments

Abstract

In two previous papers, we have proposed a part of a computational theory of argumentation, including representations for argument structure and rules for using those representations in understanding and in rebutting (Birnbaum et ai (1980) and Flowers et al (1981); related work includes Cohen (1980)). One property of the model which we emphasized is the way in which argument mechanisms and inferential memory can each help to direct the processing of the other. In particular, we presented examples in which inferential memory can uncover good rebuttals to an input as a side-effect of the processing that naturally goes on in trying to understand that input. When such opportunities for rebuttal are noticed during understanding, they render unnecessary the use of argument rules to find a response, since one has already been discovered. For example, consider the following exchange in a mock argument between an Arab and an Israeli over Middle East affairs: [ l]Arab: Israel is trying to take over the Middle East. [2] Israeli: If that were our goal, we wouldn't have given back Sinai to the Egyptians. The Israeli's understanding of the Arab's claim [1] involves instantiating a knowledge structure representing imperialism, with Israel as the actor and the Middle East as the target, and recognizing that this is intended as an accusation. This knowledge structure (let's call it TAKEOVER) has several component substructures, roughly as shown in figure 1. We propose that in trying to understand input [1]. the Israeli must relate this entire structure to his long-term memory. In so doing, he will discover, among other things.