Analyzing the Roles of Challenge and Defense in Argumentation

Abstract

The present paper introduces a model of the roles of challenge and defense in everyday, informal arguments. The model represents six basic types of challenge (acceptability, relevance, sufficiency, consistency, consecution, and completeness) and distinguishes between direct and indirect defenses. It also includes both procedural and commitment rules as well as an account of how different types of argument structure have their origins in defensive moves to challenges. Predictions from the model were tested by analyzing argumentative fragments of discussion threads from Internet newsgroups. Results indicate that justifications accompanying challenges and defensive responses to challenges are important sources of new assertions in an argument. In addition, acceptability challenges are defended through the construction of subordinately-linked arguments while relevance challenges are defended through the construction of coordinately-linked arguments. The results also suggest that commitment rules in arguments tend to be conservative for the incurring of commitments but liberal for the discharging of commitments. Findings are discussed in terms of previous research on argumentation.