1. Takeshi Suzuki, Department of English, Tsuda College ; Frans H. van Eemeren, Faculty of Humanities—Speech Communication, Argumentation Theory and Rhetoric, University of Amsterdam . An earlier version of this paper was presented at the Wake Forest/International Society for the Study of Argumentation conference, Venice, Italy, June, 2004. The authors are grateful to the other participants for their useful comments. They also thank Steven Combs for his helpful suggestions.